101
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Bohnsack KE, Bohnsack MT. Uncovering the assembly pathway of human ribosomes and its emerging links to disease. EMBO J 2019; 38:e100278. [PMID: 31268599 PMCID: PMC6600647 DOI: 10.15252/embj.2018100278] [Citation(s) in RCA: 133] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 02/18/2019] [Accepted: 04/26/2019] [Indexed: 12/12/2022] Open
Abstract
The essential cellular process of ribosome biogenesis is at the nexus of various signalling pathways that coordinate protein synthesis with cellular growth and proliferation. The fact that numerous diseases are caused by defects in ribosome assembly underscores the importance of obtaining a detailed understanding of this pathway. Studies in yeast have provided a wealth of information about the fundamental principles of ribosome assembly, and although many features are conserved throughout eukaryotes, the larger size of human (pre-)ribosomes, as well as the evolution of additional regulatory networks that can modulate ribosome assembly and function, have resulted in a more complex assembly pathway in humans. Notably, many ribosome biogenesis factors conserved from yeast appear to have subtly different or additional functions in humans. In addition, recent genome-wide, RNAi-based screens have identified a plethora of novel factors required for human ribosome biogenesis. In this review, we discuss key aspects of human ribosome production, highlighting differences to yeast, links to disease, as well as emerging concepts such as extra-ribosomal functions of ribosomal proteins and ribosome heterogeneity.
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Affiliation(s)
- Katherine E Bohnsack
- Department of Molecular BiologyUniversity Medical Center GöttingenGöttingenGermany
| | - Markus T Bohnsack
- Department of Molecular BiologyUniversity Medical Center GöttingenGöttingenGermany
- Göttingen Center for Molecular BiosciencesGeorg‐August UniversityGöttingenGermany
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102
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Proud CG. Phosphorylation and Signal Transduction Pathways in Translational Control. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a033050. [PMID: 29959191 DOI: 10.1101/cshperspect.a033050] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Protein synthesis, including the translation of specific messenger RNAs (mRNAs), is regulated by extracellular stimuli such as hormones and by the levels of certain nutrients within cells. This control involves several well-understood signaling pathways and protein kinases, which regulate the phosphorylation of proteins that control the translational machinery. These pathways include the mechanistic target of rapamycin complex 1 (mTORC1), its downstream effectors, and the mitogen-activated protein (MAP) kinase (extracellular ligand-regulated kinase [ERK]) signaling pathway. This review describes the regulatory mechanisms that control translation initiation and elongation factors, in particular the effects of phosphorylation on their interactions or activities. It also discusses current knowledge concerning the impact of these control systems on the translation of specific mRNAs or subsets of mRNAs, both in physiological processes and in diseases such as cancer.
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Affiliation(s)
- Christopher G Proud
- Nutrition & Metabolism, South Australian Health & Medical Research Institute, North Terrace, Adelaide SA5000, Australia; and School of Biological Sciences, University of Adelaide, Adelaide SA5000, Australia
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103
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mTOR and Aging: An Old Fashioned Dress. Int J Mol Sci 2019; 20:ijms20112774. [PMID: 31174250 PMCID: PMC6600378 DOI: 10.3390/ijms20112774] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/03/2019] [Accepted: 06/04/2019] [Indexed: 12/12/2022] Open
Abstract
Aging is a physiologic/pathologic process characterized by a progressive impairment of cellular functions, supported by the alterations of several molecular pathways, leading to an increased cell susceptibility to injury. This deterioration is the primary risk factor for several major human pathologies. Numerous cellular processes, including genomic instability, telomere erosion, epigenetic alterations, loss of proteostasis, deregulated nutrient-sensing, mitochondrial dysfunction, stem cell exhaustion, and altered intercellular signal transduction represent common denominators of aging in different organisms. Mammalian target of rapamycin (mTOR) is an evolutionarily conserved nutrient sensing protein kinase that regulates growth and metabolism in all eukaryotic cells. Studies in flies, worms, yeast, and mice support the hypothesis that the mTOR signalling network plays a pivotal role in modulating aging. mTOR is emerging as the most robust mediator of the protective effects of various forms of dietary restriction, which has been shown to extend lifespan and slow the onset of age-related diseases across species. Herein we discuss the role of mTor signalling network in the development of classic age-related diseases, focused on cardiovascular system, immune response, and cancer.
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104
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Sakai M, Fukumoto M, Ikai K, Ono Minagi H, Inagaki S, Kogo M, Sakai T. Role of the mTOR signalling pathway in salivary gland development. FEBS J 2019; 286:3701-3717. [DOI: 10.1111/febs.14937] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 03/06/2019] [Accepted: 05/21/2019] [Indexed: 02/01/2023]
Affiliation(s)
- Manabu Sakai
- Department of Clinical Laboratory Osaka University Dental Hospital Suita Japan
| | - Moe Fukumoto
- Department of Cell Biology National Cerebral and Cardiovascular Center Research Institute Suita Japan
| | - Kazuki Ikai
- Department of Oral‐facial Disorders Osaka University Graduate School of Dentistry Suita Japan
| | - Hitomi Ono Minagi
- Department of Oral‐facial Disorders Osaka University Graduate School of Dentistry Suita Japan
| | - Shinobu Inagaki
- Department of Child Development & Molecular Brain Science Osaka University United Graduate School of Child Development Suita Japan
| | - Mikihiko Kogo
- First Department of Oral and Maxillofacial Surgery Osaka University Graduate School of Dentistry Suita Japan
| | - Takayoshi Sakai
- Department of Oral‐facial Disorders Osaka University Graduate School of Dentistry Suita Japan
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105
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Meneguello L, Barbosa NM, Pereira KD, Proença ARG, Tamborlin L, Simabuco FM, Iwai LK, Zanelli CF, Valentini SR, Luchessi AD. The polyproline-motif of S6K2: eIF5A translational dependence and importance for protein-protein interactions. J Cell Biochem 2019; 120:6015-6025. [PMID: 30320934 DOI: 10.1002/jcb.27888] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 09/20/2018] [Indexed: 12/18/2022]
Abstract
Ribosomal S6 kinase 1 (S6K1) and S6K2 proteins are effectors of the mammalian target of rapamycin complex 1 pathway, which control the process of protein synthesis in eukaryotes. S6K2 is associated with tumor progression and has a conserved C-terminus polyproline rich motif predicted to be important for S6K2 interactions. It is noteworthy that the translation of proteins containing sequential prolines has been proposed to be dependent of eukaryotic translation initiation factor 5A (eIF5A) translation factor. Therefore, we investigated the importance of polyproline-rich region of the S6K2 for its intrinsic phosphorylation activity, protein-protein interaction and eIF5A role in S6K2 translation. In HeLa cell line, replacing S6K2 polyproline by the homologous S6K1-sequence did not affect its kinase activity and the S6K2 endogenous content was maintained after eIF5A gene silencing, even after near complete depletion of eIF5A protein. Moreover, no changes in S6K2 transcript content was observed, ruling out the possibility of compensatory regulation by increasing the mRNA content. However, in the budding yeast model, we observed that S6K2 production was impaired when compared with S6K2∆Pro, after reduction of eIF5A protein content. These results suggest that although the polyproline region of S6K2 is capable of generating ribosomal stalling, the depletion of eIF5A in HeLa cells seems to be insufficient to cause an expressive decrease in the content of endogenous S6K2. Finally, coimmunoprecipitation assays revealed that the replacement of the polyproline motif of S6K2 alters its interactome and impairs its interaction with RPS6, a key modulator of ribosome activity. These results evidence the importance of S6K2 polyproline motif in the context of S6Ks function.
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Affiliation(s)
- Leticia Meneguello
- Laboratory of Biotechnology, School of Applied Sciences, University of Campinas (UNICAMP), Limeira, Brazil
- Institute of Biosciences, Department of Biology, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Natália M Barbosa
- Department of Biological Sciences, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, Brazil
| | - Karina D Pereira
- Laboratory of Biotechnology, School of Applied Sciences, University of Campinas (UNICAMP), Limeira, Brazil
- Institute of Biosciences, Department of Biology, São Paulo State University (UNESP), Rio Claro, Brazil
| | - André R G Proença
- Laboratory of Biotechnology, School of Applied Sciences, University of Campinas (UNICAMP), Limeira, Brazil
| | - Leticia Tamborlin
- Laboratory of Biotechnology, School of Applied Sciences, University of Campinas (UNICAMP), Limeira, Brazil
- Institute of Biosciences, Department of Biology, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Fernando M Simabuco
- Laboratory of Functional Properties in Foods, School of Applied Sciences, University of Campinas (UNICAMP), Limeira, Brazil
| | - Leo K Iwai
- Special Laboratory of Applied Toxinology, Center of Toxins, Immune-Response and Cell Signaling, LETA/ CeTICS, Butantan Institute, Butanta, Brazil
| | - Cleslei F Zanelli
- Department of Biological Sciences, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, Brazil
| | - Sandro R Valentini
- Department of Biological Sciences, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, Brazil
| | - Augusto D Luchessi
- Laboratory of Biotechnology, School of Applied Sciences, University of Campinas (UNICAMP), Limeira, Brazil
- Institute of Biosciences, Department of Biology, São Paulo State University (UNESP), Rio Claro, Brazil
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106
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Li L, Zhu T, Song Y, Luo X, Feng L, Zhuo F, Li F, Ren M. Functional Characterization of Target of Rapamycin Signaling in Verticillium dahliae. Front Microbiol 2019; 10:501. [PMID: 30918504 PMCID: PMC6424901 DOI: 10.3389/fmicb.2019.00501] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 02/27/2019] [Indexed: 12/11/2022] Open
Abstract
More than 200 plants have been suffering from Verticillium wilt caused by Verticillium dahliae (V. dahliae) across the world. The target of rapamycin (TOR) is a lethal gene and controls cell growth and development in various eukaryotes, but little is known about TOR signaling in V. dahliae. Here, we found that V. dahliae strain is hypersensitive to rapamycin in the presence of rapamycin binding protein VdFKBP12 while the deletion mutant aaavdfkbp12 is insensitive to rapamycin. Heterologous expressing VdFKBP12 in Arabidopsis conferred rapamycin sensitivity, indicating that VdFKBP12 can bridge the interaction between rapamycin and TOR across species. The key across species of TOR complex 1 (TORC1) and TORC2 have been identified in V. dahliae, suggesting that TOR signaling pathway is evolutionarily conserved in eukaryotic species. Furthermore, the RNA-seq analysis showed that ribosomal biogenesis, RNA polymerase II transcription factors and many metabolic processes were significantly suppressed in rapamycin treated cells of V. dahliae. Importantly, transcript levels of genes associated with cell wall degrading enzymes (CWEDs) were dramatically down-regulated in TOR-inhibited cells. Further infection assay showed that the pathogenicity of V. dahliae and occurrence of Verticillium wilt can be blocked in the presence of rapamycin. These observations suggested that VdTOR is a key target of V. dahliae for controlling and preventing Verticillium wilt in plants.
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Affiliation(s)
- Linxuan Li
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Tingting Zhu
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Yun Song
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, China.,National Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Xiumei Luo
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Li Feng
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Fengping Zhuo
- School of Life Sciences, Chongqing University, Chongqing, China.,School of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing, China
| | - Fuguang Li
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, China.,National Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Maozhi Ren
- School of Life Sciences, Chongqing University, Chongqing, China
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107
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Tian Z, Ma X, Deng D, Cui Y, Chen W. Influence of Nitrogen Levels on Nutrient Transporters and Regulators of Protein Synthesis in Small Intestinal Enterocytes of Piglets. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:2782-2793. [PMID: 30785738 DOI: 10.1021/acs.jafc.8b06712] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
To investigate effects of dietary nitrogen level on nutrient absorption and utilization in small intestinal enterocyte of piglets, weaned piglets were fed for 10 days with diets containing 20%, 17%, or 14% crude protein (CP) with supplementation to meet requirements for essential amino acids in vivo, and IPEC-1 cells were cultured with different nitrogen levels (NL) in a culture medium (70%, 85%, and 100%) in vitro by monocultured and cocultured intestinal porcine epithelial cells (IPEC-1) and human gastric epithelial cells (GES-1). The results showed the following: (1) In animal trial, decreased dietary CP reduced transcript abundance of nutrient transporters like CAT1, PepT1, GLUT2, and SGLT-1 in jejunal mucosa (0.09 ± 0.03, P < 0.0001; 0.40 ± 0.04, P = 0.0087; 0.20 ± 0.07, P = 0.0003; 0.35 ± 0.02, P = 0.0001), but 17% CP diet did not affect jejunal protein synthesis. (2) The transcript abundance of nutrient transporters displayed similarly effective tendency in jejunal mucosa and cocultured IPEC-1 rather than that in monocultured IPEC-1. (3) Decreased nitrogen levels reduced expressive abundance of PI3K, Class 3 PI3K, TSC2, and 4E-BP1 in monocultured IPEC-1, but 85% nitrogen level did not affect expressive abundance of PI3K, TSC2, mTORC1, 4E-BP1, and S6K1 in cocultured IPEC-1. In general, decreased 3% CP or 15% nitrogen level reduced relative transcript expression of nutrient transporters, but did not affect protein synthesis in jejunal mucosa and cocultured IPEC-1. Therefore, decreased 3% dietary CP increased utilized and synthetic efficiency of nitrogen resource in small intestine and was beneficial in saving the dietary nitrogen resource.
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Affiliation(s)
- Zhimei Tian
- Institute of Animal Science , Guangdong Academy of Agricultural Sciences , Guangzhou 510640 , China
- The Key Laboratory of Animal Nutrition and Feed Science (South China) of Ministry of Agriculture, Institute of Animal Science , Guangdong Academy of Agricultural Sciences , Guangzhou 510640 , China
- State Key Laboratory of Livestock and Poultry Breeding, Guangzhou 510640 , China
- Guangdong Engineering Technology Research Center of Animal Meat Quality and Safety Control and Evaluation, Institute of Animal Science , Guangdong Academy of Agricultural Sciences , Guangzhou 510640 , China
| | - Xianyong Ma
- Institute of Animal Science , Guangdong Academy of Agricultural Sciences , Guangzhou 510640 , China
- The Key Laboratory of Animal Nutrition and Feed Science (South China) of Ministry of Agriculture, Institute of Animal Science , Guangdong Academy of Agricultural Sciences , Guangzhou 510640 , China
- State Key Laboratory of Livestock and Poultry Breeding, Guangzhou 510640 , China
- Guangdong Engineering Technology Research Center of Animal Meat Quality and Safety Control and Evaluation, Institute of Animal Science , Guangdong Academy of Agricultural Sciences , Guangzhou 510640 , China
| | - Dun Deng
- Institute of Animal Science , Guangdong Academy of Agricultural Sciences , Guangzhou 510640 , China
- The Key Laboratory of Animal Nutrition and Feed Science (South China) of Ministry of Agriculture, Institute of Animal Science , Guangdong Academy of Agricultural Sciences , Guangzhou 510640 , China
- State Key Laboratory of Livestock and Poultry Breeding, Guangzhou 510640 , China
- Guangdong Engineering Technology Research Center of Animal Meat Quality and Safety Control and Evaluation, Institute of Animal Science , Guangdong Academy of Agricultural Sciences , Guangzhou 510640 , China
| | - Yiyan Cui
- Institute of Animal Science , Guangdong Academy of Agricultural Sciences , Guangzhou 510640 , China
- The Key Laboratory of Animal Nutrition and Feed Science (South China) of Ministry of Agriculture, Institute of Animal Science , Guangdong Academy of Agricultural Sciences , Guangzhou 510640 , China
- State Key Laboratory of Livestock and Poultry Breeding, Guangzhou 510640 , China
- Guangdong Engineering Technology Research Center of Animal Meat Quality and Safety Control and Evaluation, Institute of Animal Science , Guangdong Academy of Agricultural Sciences , Guangzhou 510640 , China
| | - Weidong Chen
- Institute of Animal Science , Guangdong Academy of Agricultural Sciences , Guangzhou 510640 , China
- The Key Laboratory of Animal Nutrition and Feed Science (South China) of Ministry of Agriculture, Institute of Animal Science , Guangdong Academy of Agricultural Sciences , Guangzhou 510640 , China
- State Key Laboratory of Livestock and Poultry Breeding, Guangzhou 510640 , China
- Guangdong Engineering Technology Research Center of Animal Meat Quality and Safety Control and Evaluation, Institute of Animal Science , Guangdong Academy of Agricultural Sciences , Guangzhou 510640 , China
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108
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Svatek RS, Ji N, de Leon E, Mukherjee NZ, Kabra A, Hurez V, Nicolas M, Michalek JE, Javors M, Wheeler K, Sharp ZD, Livi CB, Shu ZJ, Henkes D, Curiel TJ. Rapamycin Prevents Surgery-Induced Immune Dysfunction in Patients with Bladder Cancer. Cancer Immunol Res 2019; 7:466-475. [PMID: 30563829 PMCID: PMC6926429 DOI: 10.1158/2326-6066.cir-18-0336] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 09/18/2018] [Accepted: 12/10/2018] [Indexed: 11/16/2022]
Abstract
The mechanistic target of rapamycin (mTOR) integrates environmental inputs to regulate cellular growth and metabolism in tumors. However, mTOR also regulates T-cell differentiation and activation, rendering applications of mTOR inhibitors toward treating cancer complex. Preclinical data support distinct biphasic effects of rapamycin, with higher doses directly suppressing tumor cell growth and lower doses enhancing T-cell immunity. To address the translational relevance of these findings, the effects of the mTOR complex 1 (mTORC1) inhibitor, rapamycin, on tumor and T cells were monitored in patients undergoing cystectomy for bladder cancer. MB49 syngeneic murine bladder cancer models were tested to gain mechanistic insights. Surgery-induced T-cell exhaustion in humans and mice and was associated with increased pulmonary metastasis and decreased PD-L1 antibody efficacy in mouse bladder cancer. At 3 mg orally daily, rapamycin concentrations were 2-fold higher in bladder tissues than in blood. Rapamycin significantly inhibited tumor mTORC1, shown by decreased rpS6 phosphorylation in treated versus control patients (P = 0.008). Rapamycin reduced surgery-induced T-cell exhaustion in patients, evidenced by a significant decrease in the prevalence of dysfunctional programmed death-1 (PD-1)-expressing T cells. Grade 3 to 4 adverse event rates were similar between groups, but rapamycin-treated patients had a higher rate of wound complications versus controls. In conclusion, surgery promoted bladder cancer metastasis and decreased the efficacy of postoperative bladder cancer immunotherapy. Low-dose (3 mg daily) oral rapamycin has favorable pharmacodynamic and immune modulating activity in surgical patients and has the potential to decrease surgery-induced immune dysfunction.
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Affiliation(s)
- Robert S Svatek
- Experimental Developmental Therapeutics (EDT) Program, UT Health MD Anderson, San Antonio, Texas.
- Department of Urology, UT Health San Antonio, San Antonio, Texas
| | - Niannian Ji
- Experimental Developmental Therapeutics (EDT) Program, UT Health MD Anderson, San Antonio, Texas
- Department of Urology, UT Health San Antonio, San Antonio, Texas
| | - Essel de Leon
- Department of Pathology, UT Health San Antonio, San Antonio, Texas
| | - Neelam Z Mukherjee
- Experimental Developmental Therapeutics (EDT) Program, UT Health MD Anderson, San Antonio, Texas
- Department of Urology, UT Health San Antonio, San Antonio, Texas
| | - Aashish Kabra
- Department of Urology, UT Health San Antonio, San Antonio, Texas
| | - Vincent Hurez
- Experimental Developmental Therapeutics (EDT) Program, UT Health MD Anderson, San Antonio, Texas
| | - Marlo Nicolas
- Department of Pathology, UT Health San Antonio, San Antonio, Texas
| | - Joel E Michalek
- Department of Epidemiology and Biostatistics, UT Health San Antonio, San Antonio, Texas
| | - Martin Javors
- Department of Psychiatry, UT Health San Antonio, San Antonio, Texas
| | - Karen Wheeler
- Experimental Developmental Therapeutics (EDT) Program, UT Health MD Anderson, San Antonio, Texas
- Department of Urology, UT Health San Antonio, San Antonio, Texas
| | - Z Dave Sharp
- The Population Science and Prevention (PSP) Program, Mays Cancer Center at UT Health MD Anderson, San Antonio, Texas
- Barshop Institute for Longevity and Aging Studies, UT Health San Antonio, San Antonio
| | - Carolina B Livi
- Department of Molecular Medicine, UT Health San Antonio, San Antonio, Texas
- Agilent Technologies, Santa Clara, California
| | - Zhen-Ju Shu
- Experimental Developmental Therapeutics (EDT) Program, UT Health MD Anderson, San Antonio, Texas
- Department of Urology, UT Health San Antonio, San Antonio, Texas
| | - David Henkes
- Department of Pathology, CHRISTUS Santa Rosa Medical Center, San Antonio, Texas
| | - Tyler J Curiel
- Experimental Developmental Therapeutics (EDT) Program, UT Health MD Anderson, San Antonio, Texas.
- Division of Hematology/Medical Oncology at the UT Health San Antonio, San Antonio, Texas
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109
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Uchenunu O, Pollak M, Topisirovic I, Hulea L. Oncogenic kinases and perturbations in protein synthesis machinery and energetics in neoplasia. J Mol Endocrinol 2019; 62:R83-R103. [PMID: 30072418 PMCID: PMC6347283 DOI: 10.1530/jme-18-0058] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 08/01/2018] [Indexed: 12/17/2022]
Abstract
Notwithstanding that metabolic perturbations and dysregulated protein synthesis are salient features of cancer, the mechanism underlying coordination of cellular energy balance with mRNA translation (which is the most energy consuming process in the cell) is poorly understood. In this review, we focus on recently emerging insights in the molecular underpinnings of the cross-talk between oncogenic kinases, translational apparatus and cellular energy metabolism. In particular, we focus on the central signaling nodes that regulate these processes (e.g. the mechanistic/mammalian target of rapamycin MTOR) and the potential implications of these findings on improving the anti-neoplastic efficacy of oncogenic kinase inhibitors.
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Affiliation(s)
- Oro Uchenunu
- Lady Davis Institute, SMBD JGH, McGill University, Montreal, Quebec, Canada
- Department of Experimental Medicine, Montreal, Quebec, Canada
| | - Michael Pollak
- Lady Davis Institute, SMBD JGH, McGill University, Montreal, Quebec, Canada
- Department of Experimental Medicine, Montreal, Quebec, Canada
- Gerald Bronfman Department of Oncology, Montreal, Quebec, Canada
| | - Ivan Topisirovic
- Lady Davis Institute, SMBD JGH, McGill University, Montreal, Quebec, Canada
- Department of Experimental Medicine, Montreal, Quebec, Canada
- Gerald Bronfman Department of Oncology, Montreal, Quebec, Canada
- Biochemistry Department, McGill University, Montreal, Quebec, Canada
| | - Laura Hulea
- Lady Davis Institute, SMBD JGH, McGill University, Montreal, Quebec, Canada
- Gerald Bronfman Department of Oncology, Montreal, Quebec, Canada
- Correspondence should be addressed to L Hulea:
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110
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Goodman CA. Role of mTORC1 in mechanically induced increases in translation and skeletal muscle mass. J Appl Physiol (1985) 2019; 127:581-590. [PMID: 30676865 DOI: 10.1152/japplphysiol.01011.2018] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Skeletal muscle mass is, in part, regulated by the rate of mRNA translation (i.e., protein synthesis). The conserved serine/threonine kinase, mTOR (the mammalian/mechanistic target of rapamycin), found in the multiprotein complex, mTOR complex 1 (mTORC1), is a major positive regulator of protein synthesis. The purpose of this review is to describe some of the critical steps in translation initiation, mTORC1 and its potential direct and indirect roles in regulating translation, and evidence that mTORC1 regulates protein synthesis and muscle mass, with a particular focus on basal conditions and the response to mechanical stimuli. Current evidence suggests that for acute contraction models of mechanical stimuli, there is an emerging pattern suggesting that there is an early increase in protein synthesis governed by a rapamycin-sensitive mTORC1-dependent mechanism, while at later poststimulation time points, the mechanism may change to a rapamycin-insensitive mTORC1-dependent or even an mTORC1-independent mechanism. Furthermore, evidence suggests that mTORC1 appears to be absolutely necessary for muscle fiber hypertrophy induced by chronic mechanical loading but may only play a partial role in the hypertrophy induced by more intermittent types of acute resistance exercise, with the possibility of mTORC1-independent mechanisms also playing a role. Despite the progress that has been made, many questions about the activation of mTORC1, and its downstream targets, remain to be answered. Further research will hopefully provide novel insights into the regulation of skeletal muscle mTORC1 that may eventually be translated into novel exercise programing and/or targeted pharmacological therapies aimed at preventing muscle wasting and/or increasing muscle mass.
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Affiliation(s)
- Craig A Goodman
- Institute of Health and Sport; Victoria University, Melbourne, Australia.,Australian Institute for Musculoskeletal Science (AIMSS), Victoria University, St. Albans, Victoria, Australia
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111
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Figueiredo VC, McCarthy JJ. Regulation of Ribosome Biogenesis in Skeletal Muscle Hypertrophy. Physiology (Bethesda) 2019; 34:30-42. [PMID: 30540235 PMCID: PMC6383632 DOI: 10.1152/physiol.00034.2018] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/11/2018] [Accepted: 09/13/2018] [Indexed: 01/22/2023] Open
Abstract
The ribosome is the enzymatic macromolecular machine responsible for protein synthesis. The rates of protein synthesis are primarily dependent on translational efficiency and capacity. Ribosome biogenesis has emerged as an important regulator of skeletal muscle growth and maintenance by altering the translational capacity of the cell. Here, we provide evidence to support a central role for ribosome biogenesis in skeletal muscle growth during postnatal development and in response to resistance exercise training. Furthermore, we discuss the cellular signaling pathways regulating ribosome biogenesis, discuss how myonuclear accretion affects translational capacity, and explore future areas of investigation within the field.
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Affiliation(s)
- Vandré Casagrande Figueiredo
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky , Lexington, Kentucky
- Department of Rehabilitation Sciences, College of Medicine, University of Kentucky , Lexington, Kentucky
| | - John J McCarthy
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky , Lexington, Kentucky
- Department of Physiology, University of Kentucky , Lexington, Kentucky
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112
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Single-cell analyses demonstrate that a heme-GATA1 feedback loop regulates red cell differentiation. Blood 2018; 133:457-469. [PMID: 30530752 DOI: 10.1182/blood-2018-05-850412] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 12/01/2018] [Indexed: 01/07/2023] Open
Abstract
Erythropoiesis is the complex, dynamic, and tightly regulated process that generates all mature red blood cells. To understand this process, we mapped the developmental trajectories of progenitors from wild-type, erythropoietin-treated, and Flvcr1-deleted mice at single-cell resolution. Importantly, we linked the quantity of each cell's surface proteins to its total transcriptome, which is a novel method. Deletion of Flvcr1 results in high levels of intracellular heme, allowing us to identify heme-regulated circuitry. Our studies demonstrate that in early erythroid cells (CD71+Ter119neg-lo), heme increases ribosomal protein transcripts, suggesting that heme, in addition to upregulating globin transcription and translation, guarantees ample ribosomes for globin synthesis. In later erythroid cells (CD71+Ter119lo-hi), heme decreases GATA1, GATA1-target gene, and mitotic spindle gene expression. These changes occur quickly. For example, in confirmatory studies using human marrow erythroid cells, ribosomal protein transcripts and proteins increase, and GATA1 transcript and protein decrease, within 15 to 30 minutes of amplifying endogenous heme synthesis with aminolevulinic acid. Because GATA1 initiates heme synthesis, GATA1 and heme together direct red cell maturation, and heme stops GATA1 synthesis, our observations reveal a GATA1-heme autoregulatory loop and implicate GATA1 and heme as the comaster regulators of the normal erythroid differentiation program. In addition, as excessive heme could amplify ribosomal protein imbalance, prematurely lower GATA1, and impede mitosis, these data may help explain the ineffective (early termination of) erythropoiesis in Diamond Blackfan anemia and del(5q) myelodysplasia, disorders with excessive heme in colony-forming unit-erythroid/proerythroblasts, explain why these anemias are macrocytic, and show why children with GATA1 mutations have DBA-like clinical phenotypes.
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113
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Madak JT, Bankhead A, Cuthbertson CR, Showalter HD, Neamati N. Revisiting the role of dihydroorotate dehydrogenase as a therapeutic target for cancer. Pharmacol Ther 2018; 195:111-131. [PMID: 30347213 DOI: 10.1016/j.pharmthera.2018.10.012] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Identified as a hallmark of cancer, metabolic reprogramming allows cancer cells to rapidly proliferate, resist chemotherapies, invade, metastasize, and survive a nutrient-deprived microenvironment. Rapidly growing cells depend on sufficient concentrations of nucleotides to sustain proliferation. One enzyme essential for the de novo biosynthesis of pyrimidine-based nucleotides is dihydroorotate dehydrogenase (DHODH), a known therapeutic target for multiple diseases. Brequinar, leflunomide, and teriflunomide, all of which are potent DHODH inhibitors, have been clinically evaluated but failed to receive FDA approval for the treatment of cancer. Inhibition of DHODH depletes intracellular pyrimidine nucleotide pools and results in cell cycle arrest in S-phase, sensitization to current chemotherapies, and differentiation in neural crest cells and acute myeloid leukemia (AML). Furthermore, DHODH is a synthetic lethal susceptibility in several oncogenic backgrounds. Therefore, DHODH-targeted therapy has potential value as part of a combination therapy for the treatment of cancer. In this review, we focus on the de novo pyrimidine biosynthesis pathway as a target for cancer therapy, and in particular, DHODH. In the first part, we provide a comprehensive overview of this pathway and its regulation in cancer. We further describe the relevance of DHODH as a target for cancer therapy using bioinformatic analyses. We then explore the preclinical and clinical results of pharmacological strategies to target the de novo pyrimidine biosynthesis pathway, with an emphasis on DHODH. Finally, we discuss potential strategies to harness DHODH as a target for the treatment of cancer.
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Affiliation(s)
- Joseph T Madak
- Department of Medicinal Chemistry, University of Michigan College of Pharmacy, Rogel Cancer Center, Ann Arbor, MI 48109, USA
| | - Armand Bankhead
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, MI 48109, USA; Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Christine R Cuthbertson
- Department of Medicinal Chemistry, University of Michigan College of Pharmacy, Rogel Cancer Center, Ann Arbor, MI 48109, USA
| | - Hollis D Showalter
- Department of Medicinal Chemistry, University of Michigan College of Pharmacy, Rogel Cancer Center, Ann Arbor, MI 48109, USA.
| | - Nouri Neamati
- Department of Medicinal Chemistry, University of Michigan College of Pharmacy, Rogel Cancer Center, Ann Arbor, MI 48109, USA.
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114
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Roy D, Kahler DJ, Yun C, Hubbard EJA. Functional Interactions Between rsks-1/S6K, glp-1/Notch, and Regulators of Caenorhabditis elegans Fertility and Germline Stem Cell Maintenance. G3 (BETHESDA, MD.) 2018; 8:3293-3309. [PMID: 30126834 PMCID: PMC6169383 DOI: 10.1534/g3.118.200511] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/06/2018] [Indexed: 12/17/2022]
Abstract
The proper accumulation and maintenance of stem cells is critical for organ development and homeostasis. The Notch signaling pathway maintains stem cells in diverse organisms and organ systems. In Caenorhabditis elegans, GLP-1/Notch activity prevents germline stem cell (GSC) differentiation. Other signaling mechanisms also influence the maintenance of GSCs, including the highly-conserved TOR substrate ribosomal protein S6 kinase (S6K). Although C. elegans bearing either a null mutation in rsks-1/S6K or a reduction-of-function (rf) mutation in glp-1/Notch produce half the normal number of adult germline progenitors, virtually all these single mutant animals are fertile. However, glp-1(rf) rsks-1(null) double mutant animals are all sterile, and in about half of their gonads, all GSCs differentiate, a distinctive phenotype associated with a significant reduction or loss of GLP-1 signaling. How rsks-1/S6K promotes GSC fate is unknown. Here, we determine that rsks-1/S6K acts germline-autonomously to maintain GSCs, and that it does not act through Cyclin-E or MAP kinase in this role. We found that interfering with translation also enhances glp-1(rf), but that regulation through rsks-1 cannot fully account for this effect. In a genome-scale RNAi screen for genes that act similarly to rsks-1/S6K, we identified 56 RNAi enhancers of glp-1(rf) sterility, many of which were previously not known to interact functionally with Notch. Further investigation revealed at least six candidates that, by genetic criteria, act linearly with rsks-1/S6K. These include genes encoding translation-related proteins, cacn-1/Cactin, an RNA exosome component, and a Hedgehog-related ligand. We found that additional Hedgehog-related ligands may share functional relationships with glp-1/Notch and rsks-1/S6K in maintaining germline progenitors.
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Affiliation(s)
- Debasmita Roy
- Skirball Institute of Biomolecular Medicine, Departments of Cell Biology and Pathology, New York University School of Medicine, New York, NY 10016
| | - David J Kahler
- NYU High Throughput Biology Laboratory, NYU Langone Health, New York, NY 10016
| | - Chi Yun
- NYU High Throughput Biology Laboratory, NYU Langone Health, New York, NY 10016
| | - E Jane Albert Hubbard
- Skirball Institute of Biomolecular Medicine, Departments of Cell Biology and Pathology, New York University School of Medicine, New York, NY 10016
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115
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Mészáros G, Pasquier A, Vivot K, Goginashvili A, Ricci R. Lysosomes in nutrient signalling: A focus on pancreatic β-cells. Diabetes Obes Metab 2018; 20 Suppl 2:104-115. [PMID: 30230186 DOI: 10.1111/dom.13389] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/24/2018] [Accepted: 05/28/2018] [Indexed: 01/12/2023]
Abstract
Regulated insulin secretion from pancreatic β-cells is a major process maintaining glucose homeostasis in mammals. Enhancing insulin release in response to chronic nutrient overload and obesity-related insulin resistance (pre-diabetes) requires several adaptive cellular mechanisms maintaining β-cell health under such stresses. Once these mechanisms are overwhelmed, β-cell failure occurs leading to full-blown Type 2 Diabetes (T2D). Nutrient-dependent macroautophagy represents one such adaptive mechanism in β-cells. While macroautophagy levels are high and protective in β-cells in pre-diabetes, they decrease at later stages contributing to β-cell failure. However, mechanisms compromising macroautophagy in β-cells remain poorly understood. In this review, we discuss how recently discovered signalling cascades that emanate from the limiting membrane of lysosomes contribute to changes in macroautophagy flux in physiology and disease. In particular, these mechanisms are put into context with β-cell function highlighting most recently described links between nutrient-dependent lysosomal signalling pathways and insulin secretion. Understanding these mechanisms in response to metabolic stress might pave the way for development of more tailored treatment strategies aimed at preserving β-cell health.
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Affiliation(s)
- Gergő Mészáros
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
- Laboratoire de Biochimie et de Biologie Moléculaire, Nouvel Hôpital Civil, Strasbourg, France
| | - Adrien Pasquier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
| | - Kevin Vivot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
| | - Alexander Goginashvili
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California
| | - Romeo Ricci
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
- Laboratoire de Biochimie et de Biologie Moléculaire, Nouvel Hôpital Civil, Strasbourg, France
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116
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SAHA and cisplatin sensitize gastric cancer cells to doxorubicin by induction of DNA damage, apoptosis and perturbation of AMPK-mTOR signalling. Exp Cell Res 2018; 370:283-291. [PMID: 29959912 DOI: 10.1016/j.yexcr.2018.06.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 06/21/2018] [Accepted: 06/26/2018] [Indexed: 12/23/2022]
Abstract
Chemotherapy remains the most prescribed anti-cancer therapy, despite patients suffering severe side effects and frequently developing chemoresistance. These complications can be partially overcome by combining different chemotherapeutic agents that target multiple biological pathways. However, selecting efficacious drug combinations remains challenging. We previously used fission yeast Schizosaccharomycespombe as a surrogate model to predict drug combinations, and showed that suberoylanilide hydroxamic acid (SAHA) and cisplatin can sensitise gastric adenocarcinoma cells toward the cytotoxic effects of doxorubicin. Yet, how this combination undermines cell viability is unknown. Here, we show that SAHA and doxorubicin markedly enhance the cleavage of two apoptosis markers, caspase 3 and poly-ADP ribose polymerase (PARP-1), and increase the phosphorylation of γH2AX, a marker of DNA damage. Further, we found a prominent reduction in Ser485 phosphorylation of AMP-dependent protein kinase (AMPK), and reductions in its target mTOR and downstream ribosomal protein S6 phosphorylation. We show that SAHA contributes most of the effect, as confirmed using another histone deacetylase inhibitor, trichostatin A. Overall, our results show that the combination of SAHA and doxorubicin can induce apoptosis in gastric adenocarcinoma in a synthetically lethal manner, and that fission yeast offers an efficient tool for identifying potent drug combinations against human cancer cells.
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117
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mTOR inhibitors for treatment of low-risk prostate cancer. Med Hypotheses 2018; 117:63-68. [PMID: 30077200 DOI: 10.1016/j.mehy.2018.06.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/04/2018] [Accepted: 06/04/2018] [Indexed: 12/14/2022]
Abstract
Prostate cancer incidence increases with age; along with many other cancers, it could be considered a disease of aging. Prostate cancer screening has led to a significant proportion of men diagnosed with low-grade, low-stage prostate cancer who are now more likely to choose an active surveillance strategy rather than definitive treatments. Definitive treatment, such as surgery and radiation therapy, is useful for high-grade disease; however, because of the low long-term risk of progression of a low-grade disease and side effects of surgery and radiation, these treatments are less commonly used for low-grade disease. While five alpha reductase inhibitors have been shown to reduce the risk of cancer detection on subsequent biopsies for men on active surveillance, no medications have been proven to prevent progression to high-grade disease. mTOR pathways have long been known to influence prostate cancer and are targets in various prostate cancer patient populations. Low-dose mTOR inhibition with rapamycin has shown promise in pre-clinical models of prostate cancer and appear to affect cellular senescence and immunomodulation in the aging population. We hypothesize that low-dose mTOR inhibition could reduce progression of low-grade prostate cancer patients, allowing them to remain on active surveillance.
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118
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Abstract
Translation is a key step in the regulation of gene expression and one of the most energy-consuming processes in the cell. In response to various stimuli, multiple signaling pathways converge on the translational machinery to regulate its function. To date, the roles of phosphoinositide 3-kinase (PI3K)/AKT and the mitogen-activated protein kinase (MAPK) pathways in the regulation of translation are among the best understood. Both pathways engage the mechanistic target of rapamycin (mTOR) to regulate a variety of components of the translational machinery. While these pathways regulate protein synthesis in homeostasis, their dysregulation results in aberrant translation leading to human diseases, including diabetes, neurological disorders, and cancer. Here we review the roles of the PI3K/AKT and MAPK pathways in the regulation of mRNA translation. We also highlight additional signaling mechanisms that have recently emerged as regulators of the translational apparatus.
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119
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mTOR Signaling and Neural Stem Cells: The Tuberous Sclerosis Complex Model. Int J Mol Sci 2018; 19:ijms19051474. [PMID: 29772672 PMCID: PMC5983755 DOI: 10.3390/ijms19051474] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/04/2018] [Accepted: 05/11/2018] [Indexed: 12/24/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR), a serine-threonine kinase, plays a pivotal role in regulating cell growth and proliferation. Notably, a great deal of evidence indicates that mTOR signaling is also crucial in controlling proliferation and differentiation of several stem cell compartments. Consequently, dysregulation of the mTOR pathway is often associated with a variety of disease, such as cancer and metabolic and genetic disorders. For instance, hyperactivation of mTORC1 in neural stem cells (NSCs) is associated with the insurgence of neurological manifestation characterizing tuberous sclerosis complex (TSC). In this review, we survey the recent contributions of TSC physiopathology studies to understand the role of mTOR signaling in both neurogenesis and tumorigenesis and discuss how these new insights can contribute to developing new therapeutic strategies for neurological diseases and cancer.
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120
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Anders PM, Montgomery ND, Montgomery SA, Bhatt AP, Dittmer DP, Damania B. Human herpesvirus-encoded kinase induces B cell lymphomas in vivo. J Clin Invest 2018; 128:2519-2534. [PMID: 29733294 DOI: 10.1172/jci97053] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 03/16/2018] [Indexed: 12/31/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is a gammaherpesvirus that is the etiological agent of the endothelial cell cancer Kaposi's sarcoma (KS) and 2 B cell lymphoproliferative disorders, primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD). KSHV ORF36, also known as viral protein kinase (vPK), is a viral serine/threonine kinase. We previously reported that KSHV vPK enhances cell proliferation and mimics cellular S6 kinase to phosphorylate ribosomal protein S6, a protein involved in protein synthesis. We created a mouse model to analyze the function of vPK in vivo. We believe this is the first mouse tumor model of a viral kinase encoded by a pathogenic human virus. We observed increased B cell activation in the vPK transgenic mice compared with normal mice. We also found that, over time, vPK transgenic mice developed a B cell hyperproliferative disorder and/or a high-grade B cell non-Hodgkin lymphoma at a greatly increased incidence compared with littermate controls. This mouse model shows that a viral protein kinase is capable of promoting B cell activation and proliferation as well as augmenting lymphomagenesis in vivo and may therefore contribute to the development of viral cancers.
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Affiliation(s)
- Penny M Anders
- Lineberger Comprehensive Cancer Center.,Department of Microbiology and Immunology, and
| | - Nathan D Montgomery
- Department of Pathology and Laboratory Medicine, the University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Stephanie A Montgomery
- Lineberger Comprehensive Cancer Center.,Department of Pathology and Laboratory Medicine, the University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Aadra P Bhatt
- Lineberger Comprehensive Cancer Center.,Department of Microbiology and Immunology, and
| | - Dirk P Dittmer
- Lineberger Comprehensive Cancer Center.,Department of Microbiology and Immunology, and
| | - Blossom Damania
- Lineberger Comprehensive Cancer Center.,Department of Microbiology and Immunology, and
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121
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Wang C, Chu J, Fu L, Wang Y, Zhao F, Zhou D. iTRAQ-based quantitative proteomics reveals the biochemical mechanism of cold stress adaption of razor clam during controlled freezing-point storage. Food Chem 2018; 247:73-80. [DOI: 10.1016/j.foodchem.2017.12.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 11/21/2017] [Accepted: 12/04/2017] [Indexed: 12/23/2022]
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122
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Wu J, Jiang X, Li Y, Zhu T, Zhang J, Zhang Z, Zhang L, Zhang Y, Wang Y, Zou X, Liang B. PHA-4/FoxA senses nucleolar stress to regulate lipid accumulation in Caenorhabditis elegans. Nat Commun 2018; 9:1195. [PMID: 29567958 PMCID: PMC5864837 DOI: 10.1038/s41467-018-03531-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 02/16/2018] [Indexed: 12/20/2022] Open
Abstract
The primary function of the nucleolus is ribosome biogenesis, which is an extremely energetically expensive process. Failures in ribosome biogenesis cause nucleolar stress with an altered energy status. However, little is known about the underlying mechanism linking nucleolar stress to energy metabolism. Here we show that nucleolar stress is triggered by inactivation of RSKS-1 (ribosomal protein S6 kinase), RRP-8 (ribosomal RNA processing 8), and PRO-2/3 (proximal proliferation), all of which are involved in ribosomal RNA processing or inhibition of rDNA transcription by actinomycin D (AD), leading to excessive lipid accumulation in Caenorhabditis elegans. The transcription factor PHA-4/FoxA acts as a sensor of nucleolar stress to bind to and transactivate the expression of the lipogenic genes pod-2 (acetyl-CoA carboxylase), fasn-1 (fatty acid synthase), and dgat-2 (diacylglycerol O-acyltransferase 2), consequently promoting lipid accumulation. Importantly, inactivation of pha-4 or dgat-2 is sufficient to abolish nucleolar stress-induced lipid accumulation and prolonged starvation survival. The results revealed a distinct PHA-4-mediated lipogenesis pathway that senses nucleolar stress and shifts excessive energy for storage as fat.
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Affiliation(s)
- Jieyu Wu
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Center for Excellence in Animal Evolution and Genetics, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, 650204, China
| | - Xue Jiang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Center for Excellence in Animal Evolution and Genetics, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, 650204, China
| | - Yamei Li
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Center for Excellence in Animal Evolution and Genetics, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
- School of Life Science, University of Science and Technology of China, Hefei, 230027, China
| | - Tingting Zhu
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Center for Excellence in Animal Evolution and Genetics, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, 650204, China
| | - Jingjing Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Center for Excellence in Animal Evolution and Genetics, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
- Department of Hepatobiliary Surgery, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001, China
| | - Zhiguo Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Center for Excellence in Animal Evolution and Genetics, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, 650204, China
| | - Linqiang Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Center for Excellence in Animal Evolution and Genetics, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
| | - Yuru Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Center for Excellence in Animal Evolution and Genetics, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
| | - Yanli Wang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Center for Excellence in Animal Evolution and Genetics, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
| | - Xiaoju Zou
- Key Laboratory of Special Biological Resource Development and Utilization of University in Yunnan Province, Department of Life Science and Biotechnology, Kunming University, Kunming, 650214, China.
| | - Bin Liang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Center for Excellence in Animal Evolution and Genetics, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China.
- Department of Hepatobiliary Surgery, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001, China.
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123
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Tee AR. The Target of Rapamycin and Mechanisms of Cell Growth. Int J Mol Sci 2018; 19:ijms19030880. [PMID: 29547541 PMCID: PMC5877741 DOI: 10.3390/ijms19030880] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 03/12/2018] [Accepted: 03/13/2018] [Indexed: 01/09/2023] Open
Abstract
Mammalian target of rapamycin (mTOR, now referred to as mechanistic target of rapamycin) is considered as the master regulator of cell growth. A definition of cell growth is a build-up of cellular mass through the biosynthesis of macromolecules. mTOR regulation of cell growth and cell size is complex, involving tight regulation of both anabolic and catabolic processes. Upon a growth signal input, mTOR enhances a range of anabolic processes that coordinate the biosynthesis of macromolecules to build cellular biomass, while restricting catabolic processes such as autophagy. mTOR is highly dependent on the supply of nutrients and energy to promote cell growth, where the network of signalling pathways that influence mTOR activity ensures that energy and nutrient homeostasis are retained within the cell as they grow. As well as maintaining cell size, mTOR is fundamental in the regulation of organismal growth. This review examines the complexities of how mTOR complex 1 (mTORC1) enhances the cell’s capacity to synthesis de novo proteins required for cell growth. It also describes the discovery of mTORC1, the complexities of cell growth signalling involving nutrients and energy supply, as well as the multifaceted regulation of mTORC1 to orchestrate ribosomal biogenesis and protein translation.
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Affiliation(s)
- Andrew R Tee
- Division of Cancer and Genetics, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.
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124
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Abstract
Stress granules are cytoplasmic mRNA-protein complexes that form upon the inhibition of translation initiation and promote cell survival in response to environmental insults. However, they are often associated with pathologies, including neurodegeneration and cancer, and changes in their dynamics are implicated in ageing. Here we show that the mTOR effector kinases S6 kinase 1 (S6K1) and S6 kinase 2 (S6K2) localise to stress granules in human cells and are required for their assembly and maintenance after mild oxidative stress. The roles of S6K1 and S6K2 are distinct, with S6K1 having a more significant role in the formation of stress granules via the regulation of eIF2α phosphorylation, while S6K2 is important for their persistence. In C. elegans, the S6 kinase orthologue RSKS-1 promotes the assembly of stress granules and its loss of function sensitises the nematodes to stress-induced death. This study identifies S6 kinases as regulators of stress granule dynamics and provides a novel link between mTOR signalling, translation inhibition and survival.
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125
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Kang J, Kusnadi EP, Ogden AJ, Hicks RJ, Bammert L, Kutay U, Hung S, Sanij E, Hannan RD, Hannan KM, Pearson RB. Amino acid-dependent signaling via S6K1 and MYC is essential for regulation of rDNA transcription. Oncotarget 2018; 7:48887-48904. [PMID: 27385002 PMCID: PMC5226478 DOI: 10.18632/oncotarget.10346] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 06/15/2016] [Indexed: 12/25/2022] Open
Abstract
Dysregulation of RNA polymerase I (Pol I)-dependent ribosomal DNA (rDNA) transcription is a consistent feature of malignant transformation that can be targeted to treat cancer. Understanding how rDNA transcription is coupled to the availability of growth factors and nutrients will provide insight into how ribosome biogenesis is maintained in a tumour environment characterised by limiting nutrients. We demonstrate that modulation of rDNA transcription initiation, elongation and rRNA processing is an immediate, co-regulated response to altered amino acid abundance, dependent on both mTORC1 activation of S6K1 and MYC activity. Growth factors regulate rDNA transcription initiation while amino acids modulate growth factor-dependent rDNA transcription by primarily regulating S6K1-dependent rDNA transcription elongation and processing. Thus, we show for the first time amino acids regulate rRNA synthesis by a distinct, post-initiation mechanism, providing a novel model for integrated control of ribosome biogenesis that has implications for understanding how this process is dysregulated in cancer.
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Affiliation(s)
- Jian Kang
- Oncogenic Signaling and Growth Control Program, Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, Victoria, Australia
| | - Eric P Kusnadi
- Oncogenic Signaling and Growth Control Program, Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, Victoria, Australia
| | - Allison J Ogden
- Oncogenic Signaling and Growth Control Program, Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, Victoria, Australia
| | - Rodney J Hicks
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia.,Molecular Imaging and Targeted Therapeutics Laboratory, Cancer Therapeutics Program, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Lukas Bammert
- Institute of Biochemistry, Department of Biology, Swiss Federal Institute of Technology Zurich, Zurich, Switzerland
| | - Ulrike Kutay
- Institute of Biochemistry, Department of Biology, Swiss Federal Institute of Technology Zurich, Zurich, Switzerland
| | - Sandy Hung
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital & Department of Ophthalmology, University of Melbourne, East Melbourne, Victoria, Australia
| | - Elaine Sanij
- Oncogenic Signaling and Growth Control Program, Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, Victoria, Australia
| | - Ross D Hannan
- Oncogenic Signaling and Growth Control Program, Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, Victoria, Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia.,Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.,School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia.,Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, The Australian National University, Canberaa, ACT, Australia
| | - Katherine M Hannan
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia.,Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, The Australian National University, Canberaa, ACT, Australia
| | - Richard B Pearson
- Oncogenic Signaling and Growth Control Program, Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, Victoria, Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia.,Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
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126
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Yeung J, Mermet J, Jouffe C, Marquis J, Charpagne A, Gachon F, Naef F. Transcription factor activity rhythms and tissue-specific chromatin interactions explain circadian gene expression across organs. Genome Res 2018; 28:182-191. [PMID: 29254942 PMCID: PMC5793782 DOI: 10.1101/gr.222430.117] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 12/11/2017] [Indexed: 11/28/2022]
Abstract
Temporal control of physiology requires the interplay between gene networks involved in daily timekeeping and tissue function across different organs. How the circadian clock interweaves with tissue-specific transcriptional programs is poorly understood. Here, we dissected temporal and tissue-specific regulation at multiple gene regulatory layers by examining mouse tissues with an intact or disrupted clock over time. Integrated analysis uncovered two distinct regulatory modes underlying tissue-specific rhythms: tissue-specific oscillations in transcription factor (TF) activity, which were linked to feeding-fasting cycles in liver and sodium homeostasis in kidney; and colocalized binding of clock and tissue-specific transcription factors at distal enhancers. Chromosome conformation capture (4C-seq) in liver and kidney identified liver-specific chromatin loops that recruited clock-bound enhancers to promoters to regulate liver-specific transcriptional rhythms. Furthermore, this looping was remarkably promoter-specific on the scale of less than 10 kilobases (kb). Enhancers can contact a rhythmic promoter while looping out nearby nonrhythmic alternative promoters, confining rhythmic enhancer activity to specific promoters. These findings suggest that chromatin folding enables the clock to regulate rhythmic transcription of specific promoters to output temporal transcriptional programs tailored to different tissues.
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Affiliation(s)
- Jake Yeung
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland
| | - Jérôme Mermet
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland
| | - Céline Jouffe
- Department of Diabetes and Circadian Rhythms, Nestlé Institute of Health Sciences, CH-1015 Lausanne, Switzerland
| | - Julien Marquis
- Functional Genomics, Nestlé Institute of Health Sciences, CH-1015 Lausanne, Switzerland
| | - Aline Charpagne
- Functional Genomics, Nestlé Institute of Health Sciences, CH-1015 Lausanne, Switzerland
| | - Frédéric Gachon
- Department of Diabetes and Circadian Rhythms, Nestlé Institute of Health Sciences, CH-1015 Lausanne, Switzerland
- Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Felix Naef
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland
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127
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Rad E, Murray JT, Tee AR. Oncogenic Signalling through Mechanistic Target of Rapamycin (mTOR): A Driver of Metabolic Transformation and Cancer Progression. Cancers (Basel) 2018; 10:cancers10010005. [PMID: 29301334 PMCID: PMC5789355 DOI: 10.3390/cancers10010005] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 12/27/2017] [Accepted: 12/28/2017] [Indexed: 12/29/2022] Open
Abstract
Throughout the years, research into signalling pathways involved in cancer progression has led to many discoveries of which mechanistic target of rapamycin (mTOR) is a key player. mTOR is a master regulator of cell growth control. mTOR is historically known to promote cell growth by enhancing the efficiency of protein translation. Research in the last decade has revealed that mTOR’s role in promoting cell growth is much more multifaceted. While mTOR is necessary for normal human physiology, cancer cells take advantage of mTOR signalling to drive their neoplastic growth and progression. Oncogenic signal transduction through mTOR is a common occurrence in cancer, leading to metabolic transformation, enhanced proliferative drive and increased metastatic potential through neovascularisation. This review focuses on the downstream mTOR-regulated processes that are implicated in the “hallmarks” of cancer with focus on mTOR’s involvement in proliferative signalling, metabolic reprogramming, angiogenesis and metastasis.
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Affiliation(s)
- Ellie Rad
- Division of Cancer and Genetics, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.
| | - James T Murray
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.
| | - Andrew R Tee
- Division of Cancer and Genetics, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.
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128
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Abstract
The ribosome is a complex molecular machine composed of numerous distinct proteins and nucleic acids and is responsible for protein synthesis in every living cell. Ribosome biogenesis is one of the most multifaceted and energy- demanding processes in biology, involving a large number of assembly and maturation factors, the functions of which are orchestrated by multiple cellular inputs, including mitogenic signals and nutrient availability. Although causal associations between inherited mutations affecting ribosome biogenesis and elevated cancer risk have been established over the past decade, mechanistic data have emerged suggesting a broader role for dysregulated ribosome biogenesis in the development and progression of most spontaneous cancers. In this Opinion article, we highlight the most recent findings that provide new insights into the molecular basis of ribosome biogenesis in cancer and offer our perspective on how these observations present opportunities for the design of new targeted cancer treatments.
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Affiliation(s)
- Joffrey Pelletier
- Laboratory of Cancer Metabolism, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Duran i Reynals, 08908 L'Hospitalet de Llobregat, Barcelona, Catalonia, Spain
| | - George Thomas
- Laboratory of Cancer Metabolism, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Duran i Reynals, 08908 L'Hospitalet de Llobregat, Barcelona, Catalonia, Spain; at the Division of Hematology and Oncology, Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, Ohio 45267, USA; and at the Unit of Biochemistry, Department of Physiological Sciences II, Faculty of Medicine, Campus Universitari de Bellvitge, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), University of Barcelona, 08908 L'Hospitalet de Llobregat, Barcelona, Catalonia, Spain
| | - Siniša Volarević
- Department of Molecular Medicine and Biotechnology, School of Medicine, University of Rijeka, Brace Branchetta 20, 51000 Rijeka, Croatia; and at the Scientific Center of Excellence for Reproductive and Regenerative Medicine, University of Rijeka, Brace Branchetta 20, 51000 Rijeka, Croatia
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129
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Puighermanal E, Biever A, Pascoli V, Melser S, Pratlong M, Cutando L, Rialle S, Severac D, Boubaker-Vitre J, Meyuhas O, Marsicano G, Lüscher C, Valjent E. Ribosomal Protein S6 Phosphorylation Is Involved in Novelty-Induced Locomotion, Synaptic Plasticity and mRNA Translation. Front Mol Neurosci 2017; 10:419. [PMID: 29311811 PMCID: PMC5742586 DOI: 10.3389/fnmol.2017.00419] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 12/01/2017] [Indexed: 11/29/2022] Open
Abstract
The phosphorylation of the ribosomal protein S6 (rpS6) is widely used to track neuronal activity. Although it is generally assumed that rpS6 phosphorylation has a stimulatory effect on global protein synthesis in neurons, its exact biological function remains unknown. By using a phospho-deficient rpS6 knockin mouse model, we directly tested the role of phospho-rpS6 in mRNA translation, plasticity and behavior. The analysis of multiple brain areas shows for the first time that, in neurons, phospho-rpS6 is dispensable for overall protein synthesis. Instead, we found that phospho-rpS6 controls the translation of a subset of mRNAs in a specific brain region, the nucleus accumbens (Acb), but not in the dorsal striatum. We further show that rpS6 phospho-mutant mice display altered long-term potentiation (LTP) in the Acb and enhanced novelty-induced locomotion. Collectively, our findings suggest a previously unappreciated role of phospho-rpS6 in the physiology of the Acb, through the translation of a selective subclass of mRNAs, rather than the regulation of general protein synthesis.
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Affiliation(s)
| | - Anne Biever
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Vincent Pascoli
- Department of Basic Neurosciences, Medical Faculty, University of Geneva, Geneva, Switzerland
| | - Su Melser
- INSERM U1215, Université de Bordeaux, NeuroCentre Magendie, Bordeaux, France
| | - Marine Pratlong
- Montpellier GenomiX, BioCampus Montpellier, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Laura Cutando
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Stephanie Rialle
- Montpellier GenomiX, BioCampus Montpellier, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Dany Severac
- Montpellier GenomiX, BioCampus Montpellier, CNRS, INSERM, University of Montpellier, Montpellier, France
| | | | - Oded Meyuhas
- Department of Biochemistry and Molecular Biology, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Giovanni Marsicano
- INSERM U1215, Université de Bordeaux, NeuroCentre Magendie, Bordeaux, France
| | - Christian Lüscher
- Department of Basic Neurosciences, Medical Faculty, University of Geneva, Geneva, Switzerland.,Clinic of Neurology, Department of Clinical Neurosciences, Geneva University Hospital, Geneva, Switzerland
| | - Emmanuel Valjent
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France
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130
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Marabita M, Baraldo M, Solagna F, Ceelen JJM, Sartori R, Nolte H, Nemazanyy I, Pyronnet S, Kruger M, Pende M, Blaauw B. S6K1 Is Required for Increasing Skeletal Muscle Force during Hypertrophy. Cell Rep 2017; 17:501-513. [PMID: 27705797 DOI: 10.1016/j.celrep.2016.09.020] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 07/19/2016] [Accepted: 09/06/2016] [Indexed: 01/06/2023] Open
Abstract
Loss of skeletal muscle mass and force aggravates age-related sarcopenia and numerous pathologies, such as cancer and diabetes. The AKT-mTORC1 pathway plays a major role in stimulating adult muscle growth; however, the functional role of its downstream mediators in vivo is unknown. Here, we show that simultaneous inhibition of mTOR signaling to both S6K1 and 4E-BP1 is sufficient to reduce AKT-induced muscle growth and render it insensitive to the mTORC1-inhibitor rapamycin. Surprisingly, lack of mTOR signaling to 4E-BP1 only, or deletion of S6K1 alone, is not sufficient to reduce muscle hypertrophy or alter its sensitivity to rapamycin. However, we report that, while not required for muscle growth, S6K1 is essential for maintaining muscle structure and force production. Hypertrophy in the absence of S6K1 is characterized by compromised ribosome biogenesis and the formation of p62-positive protein aggregates. These findings identify S6K1 as a crucial player for maintaining muscle function during hypertrophy.
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Affiliation(s)
- Manuela Marabita
- Venetian Institute of Molecular Medicine (VIMM), Via Orus 2, 35129 Padova, Italy
| | - Martina Baraldo
- Venetian Institute of Molecular Medicine (VIMM), Via Orus 2, 35129 Padova, Italy
| | - Francesca Solagna
- Venetian Institute of Molecular Medicine (VIMM), Via Orus 2, 35129 Padova, Italy
| | | | - Roberta Sartori
- Venetian Institute of Molecular Medicine (VIMM), Via Orus 2, 35129 Padova, Italy
| | - Hendrik Nolte
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Ivan Nemazanyy
- Institut Necker-Enfants Malades, Inserm, Université Paris Descartes, CS 61431 Paris, France
| | - Stéphane Pyronnet
- Université de Toulouse, Institut National de la Recherche Médicale (INSERM-UMR-1037), Centre de Recherches en Cancérologie de Toulouse (CRCT), Equipe Labellisée Ligue Contre le Cancer, 31432 Toulouse, France
| | - Marcus Kruger
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Mario Pende
- Institut Necker-Enfants Malades, Inserm, Université Paris Descartes, CS 61431 Paris, France
| | - Bert Blaauw
- Venetian Institute of Molecular Medicine (VIMM), Via Orus 2, 35129 Padova, Italy; Department of Biomedical Sciences, University of Padova, 35137 Padova, Italy.
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131
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Hilton BJ, Bradke F. Can injured adult CNS axons regenerate by recapitulating development? Development 2017; 144:3417-3429. [PMID: 28974639 DOI: 10.1242/dev.148312] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In the adult mammalian central nervous system (CNS), neurons typically fail to regenerate their axons after injury. During development, by contrast, neurons extend axons effectively. A variety of intracellular mechanisms mediate this difference, including changes in gene expression, the ability to form a growth cone, differences in mitochondrial function/axonal transport and the efficacy of synaptic transmission. In turn, these intracellular processes are linked to extracellular differences between the developing and adult CNS. During development, the extracellular environment directs axon growth and circuit formation. In adulthood, by contrast, extracellular factors, such as myelin and the extracellular matrix, restrict axon growth. Here, we discuss whether the reactivation of developmental processes can elicit axon regeneration in the injured CNS.
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Affiliation(s)
- Brett J Hilton
- Laboratory for Axon Growth and Regeneration, German Centre for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Frank Bradke
- Laboratory for Axon Growth and Regeneration, German Centre for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
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132
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Liu Y, Wei M, Guo H, Shao C, Meng L, Xu W, Wang N, Wang L, Power DM, Hou J, Mahboob S, Cui Z, Yang Y, Li Y, Zhao F, Chen S. Locus Mapping, Molecular Cloning, and Expression Analysis of rps6kb2, a Novel Metamorphosis-Related Gene in Chinese Tongue Sole (Cynoglossus semilaevis). MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2017; 19:497-516. [PMID: 28779262 DOI: 10.1007/s10126-017-9769-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 06/26/2017] [Indexed: 06/07/2023]
Abstract
Flatfish metamorphosis denotes the extraordinary transformation of a symmetric pelagic larva into an asymmetric benthic juvenile. This unique process involves eye migration, a 90° rotation in posture, and asymmetrical pigmentation for adaptation to a benthic lifestyle. In the present study, we used genetics to map a metamorphosis-related locus (q-10M) in the male linkage group (LG10M), a small interval of 0.9 cM corresponding to a 1.8 M-bp physical area in chromosome 9 in the Chinese tongue sole (Cynoglossus semilaevis). Combined with single-marker analysis, ribosomal protein S6 kinase 2 (rps6kb2) a member of the family of AGC kinases was identified as a novel metamorphosis-related candidate gene. Its expression pattern during metamorphosis was determined by quantitative RT-PCR and whole-mount in situ hybridization analysis. rps6kb2 gene was significantly expressed in metamorphic climax stage larvae and distributed in all the tissues transforming during metamorphosis, including tail, jaw, eye and skin of larvae. The results suggest that rps6kb2 has a general role in tissue transformations during flatfish metamorphosis including tail changes, skull remodeling, eye migration, and asymmetrical pigmentation.
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Affiliation(s)
- Yang Liu
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences (CAFS), Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
| | - Min Wei
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences (CAFS), Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
| | - Hua Guo
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences (CAFS), Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
- College of Fisheries and Life Science, Shanghai Ocean University, Ministry of Education, Shanghai, 201306, China
| | - Changwei Shao
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences (CAFS), Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
| | - Liang Meng
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences (CAFS), Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
| | - Wenteng Xu
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences (CAFS), Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
| | - Na Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences (CAFS), Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
| | - Lei Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences (CAFS), Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
| | - Deborah M Power
- College of Fisheries and Life Science, Shanghai Ocean University, Ministry of Education, Shanghai, 201306, China
| | - Jilun Hou
- Beidaihe Central Experiment Station, Chinese Academy of Fishery Sciences, Qinhuangdao, 066100, China
| | - Shahid Mahboob
- Department of Zoology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
- Department of Zoology, GC University, Faisalabad, 38000, Pakistan
| | - Zhongkai Cui
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences (CAFS), Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
- College of Fisheries and Life Science, Shanghai Ocean University, Ministry of Education, Shanghai, 201306, China
| | - Yingming Yang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences (CAFS), Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
| | - Yangzhen Li
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences (CAFS), Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
| | - Fazhen Zhao
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences (CAFS), Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
| | - Songlin Chen
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China.
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences (CAFS), Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, 266071, China.
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China.
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133
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Esnault S, Shen ZJ, Malter JS. Protein Translation and Signaling in Human Eosinophils. Front Med (Lausanne) 2017; 4:150. [PMID: 28971096 PMCID: PMC5609579 DOI: 10.3389/fmed.2017.00150] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 09/01/2017] [Indexed: 01/01/2023] Open
Abstract
We have recently reported that, unlike IL-5 and GM-CSF, IL-3 induces increased translation of a subset of mRNAs. In addition, we have demonstrated that Pin1 controls the activity of mRNA binding proteins, leading to enhanced mRNA stability, GM-CSF protein production and prolonged eosinophil (EOS) survival. In this review, discussion will include an overview of cap-dependent protein translation and its regulation by intracellular signaling pathways. We will address the more general process of mRNA post-transcriptional regulation, especially regarding mRNA binding proteins, which are critical effectors of protein translation. Furthermore, we will focus on (1) the roles of IL-3-driven sustained signaling on enhanced protein translation in EOS, (2) the mechanisms regulating mRNA binding proteins activity in EOS, and (3) the potential targeting of IL-3 signaling and the signaling leading to mRNA binding activity changes to identify therapeutic targets to treat EOS-associated diseases.
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Affiliation(s)
- Stephane Esnault
- Department of Medicine, Allergy, Pulmonary, and Critical Care Medicine Division, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, United States
| | - Zhong-Jian Shen
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - James S Malter
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX, United States
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134
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Translation is actively regulated during the differentiation of CD8 + effector T cells. Nat Immunol 2017; 18:1046-1057. [PMID: 28714979 PMCID: PMC5937989 DOI: 10.1038/ni.3795] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/16/2017] [Indexed: 12/15/2022]
Abstract
Translation is a critical process in protein synthesis, but translational regulation in antigen-specific T cells in vivo has not been well defined. Here we have characterized the translatome of virus-specific effector CD8+ T cells during acute LCMV infection of mice. Antigen-specific T cells exerted dynamic translational control of gene expression that correlated with cell proliferation and T cell antigen receptor (TCR) stimulation. Translation of mRNAs that encode translation machinery including ribosomal protein mRNAs was upregulated during the T cell expansion phase, followed by translational inhibition of these transcripts when the effector CD8+ T cells stopped dividing just prior to the contraction phase. This translational suppression was more pronounced in terminal effector cells compared to memory precursor cells, and was regulated by antigenic stimulation and mTOR signals. Our studies show that translational activity of transcripts encoding ribosomal proteins is regulated during effector CD8+ T cell differentiation and may play a role in fate decisions involved in the formation of memory cells.
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135
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Madala SK, Sontake V, Edukulla R, Davidson CR, Schmidt S, Hardie WD. Unique and Redundant Functions of p70 Ribosomal S6 Kinase Isoforms Regulate Mesenchymal Cell Proliferation and Migration in Pulmonary Fibrosis. Am J Respir Cell Mol Biol 2017; 55:792-803. [PMID: 27438654 DOI: 10.1165/rcmb.2016-0090oc] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The p70 ribosomal S6 kinase (p70S6K) is a downstream substrate that is phosphorylated and activated by the mammalian target of rapamycin complex and regulates multiple cellular processes associated with pulmonary fibrogenesis. Two isoforms of the p70S6K have been identified (S6K1 and S6K2), but their relative contributions in mediating pulmonary fibrosis are unknown. To interrogate the roles of the p70S6K isoforms, we overexpressed transforming growth factor (TGF)-α in mice deficient for the S6K1 or S6K2 genes and measured changes in lung histology, morphometry, total lung collagen, lung function, and proliferation between wild-type and isoform-deficient mice. Deficiency of S6K1, but not S6K2, had a significant effect on reducing proliferation in subpleural fibrotic lesions during TGF-α-induced fibrosis. Migration was significantly decreased in mesenchymal cells isolated from the lungs of S6K1 knockout mice compared with wild-type or S6K2 knockout mice. Conversely, increases in subpleural thickening were significantly decreased in S6K2-deficient mice compared with wild type. Deficiency of S6K2 significantly reduced phosphorylation of the downstream S6 ribosomal protein in lung homogenates and isolated mesenchymal cells after TGF-α expression. However, deficiency of neither isoform alone significantly altered TGF-α-induced collagen accumulation or lung function decline in vivo. Furthermore, deficiency in neither isoform prevented changes in collagen accumulation or lung compliance decline after administration of intradermal bleomycin. Together, these findings demonstrate that the p70S6K isoforms have unique and redundant functions in mediating fibrogenic processes, including proliferation, migration, and S6 phosphorylation, signifying that both isoforms must be targeted to modulate p70S6K-mediated pulmonary fibrosis.
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Affiliation(s)
- Satish K Madala
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Vishwaraj Sontake
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Ramakrishna Edukulla
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Cynthia R Davidson
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Stephanie Schmidt
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - William D Hardie
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
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136
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Khalil A, Parker M, Mpanga R, Cevik SE, Thorburn C, Suvorov A. Developmental Exposure to 2,2',4,4'-Tetrabromodiphenyl Ether Induces Long-Lasting Changes in Liver Metabolism in Male Mice. J Endocr Soc 2017; 1:323-344. [PMID: 29264491 PMCID: PMC5686773 DOI: 10.1210/js.2016-1011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 03/09/2017] [Indexed: 12/11/2022] Open
Abstract
Polybrominated diphenyl ethers (PBDEs) were used as flame-retardant additives in a wide range of polymers. The generations born when environmental concentrations of PBDEs reached their maximum account in the United States for one-fifth of the total population. We hypothesized that exposure to PBDEs during sensitive developmental windows might result in long-lasting changes in liver metabolism. The present study was based on experiments with CD-1 mice and human hepatocellular carcinoma cells (human hepatoma cell line, HepG2). Pregnant mice were exposed to 0.2 mg/kg 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) from gestation day 8 until postnatal day 21. The metabolic health-related outcomes were analyzed on postnatal day 21 and postnatal week 20 in male offspring. Several groups of metabolic genes, including ribosomal and mitochondrial genes, were significantly upregulated in the liver at both points. Genes regulated via mechanistic target of rapamycin (mTOR) pathway, the gatekeeper of metabolic homeostasis, were whether up- or downregulated at both measurement points. On postnatal day 21, but not week 20, both mTOR complexes in the liver were activated, as measured by phosphorylation of their targets. mTOR complexes were also activated by BDE-47 in HepG2 cells in vitro. The following changes were observed at week 20: a decreased number of polyploid hepatocytes, suppressed cytoplasmic S6K1, twofold greater blood insulin-like growth factor-1 and triglycerides, and 2.5-fold lower expression of fatty acid uptake membrane receptor CD36 in liver tissue. Thus, perinatal exposure to environmentally relevant doses of BDE-47 in laboratory mice results in long-lasting changes in liver physiology. Our evidence suggests involvement of the mTOR pathway in the observed metabolic programming of the liver.
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Affiliation(s)
- Ahmed Khalil
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, Massachusetts 01003
- Medical Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications, Alexandria 21934, Egypt
| | - Mikhail Parker
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Richard Mpanga
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Sebnem E. Cevik
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Cassandra Thorburn
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Alexander Suvorov
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, Massachusetts 01003
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Ruf S, Heberle AM, Langelaar-Makkinje M, Gelino S, Wilkinson D, Gerbeth C, Schwarz JJ, Holzwarth B, Warscheid B, Meisinger C, van Vugt MATM, Baumeister R, Hansen M, Thedieck K. PLK1 (polo like kinase 1) inhibits MTOR complex 1 and promotes autophagy. Autophagy 2017; 13:486-505. [PMID: 28102733 PMCID: PMC5361591 DOI: 10.1080/15548627.2016.1263781] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 11/09/2016] [Accepted: 11/16/2016] [Indexed: 02/08/2023] Open
Abstract
Mechanistic target of rapamycin complex 1 (MTORC1) and polo like kinase 1 (PLK1) are major drivers of cancer cell growth and proliferation, and inhibitors of both protein kinases are currently being investigated in clinical studies. To date, MTORC1's and PLK1's functions are mostly studied separately, and reports on their mutual crosstalk are scarce. Here, we identify PLK1 as a physical MTORC1 interactor in human cancer cells. PLK1 inhibition enhances MTORC1 activity under nutrient sufficiency and in starved cells, and PLK1 directly phosphorylates the MTORC1 component RPTOR/RAPTOR in vitro. PLK1 and MTORC1 reside together at lysosomes, the subcellular site where MTORC1 is active. Consistent with an inhibitory role of PLK1 toward MTORC1, PLK1 overexpression inhibits lysosomal association of the PLK1-MTORC1 complex, whereas PLK1 inhibition promotes lysosomal localization of MTOR. PLK1-MTORC1 binding is enhanced by amino acid starvation, a condition known to increase autophagy. MTORC1 inhibition is an important step in autophagy activation. Consistently, PLK1 inhibition mitigates autophagy in cancer cells both under nutrient starvation and sufficiency, and a role of PLK1 in autophagy is also observed in the invertebrate model organism Caenorhabditis elegans. In summary, PLK1 inhibits MTORC1 and thereby positively contributes to autophagy. Since autophagy is increasingly recognized to contribute to tumor cell survival and growth, we propose that cautious monitoring of MTORC1 and autophagy readouts in clinical trials with PLK1 inhibitors is needed to develop strategies for optimized (combinatorial) cancer therapies targeting MTORC1, PLK1, and autophagy.
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Affiliation(s)
- Stefanie Ruf
- Department of Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Department of Pediatrics, Center for Liver, Digestive and Metabolic Diseases, University of Groningen, University Medical Center Groningen, AV Groningen, The Netherlands
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- Research Training Group (RTG) 1104, University of Freiburg, Freiburg, Germany
| | - Alexander Martin Heberle
- Department of Pediatrics, Center for Liver, Digestive and Metabolic Diseases, University of Groningen, University Medical Center Groningen, AV Groningen, The Netherlands
| | - Miriam Langelaar-Makkinje
- Department of Pediatrics, Center for Liver, Digestive and Metabolic Diseases, University of Groningen, University Medical Center Groningen, AV Groningen, The Netherlands
| | - Sara Gelino
- Program of Development, Aging and Regeneration, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
- Graduate School of Biomedical Sciences, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Deepti Wilkinson
- Program of Development, Aging and Regeneration, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Carolin Gerbeth
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- ZBMZ Centre for Biochemistry and Molecular Cell Research (Faculty of Medicine), University of Freiburg, Freiburg, Germany
- Institute of Biochemistry and Molecular Biology (Faculty of Medicine), University of Freiburg, Freiburg, Germany
| | - Jennifer Jasmin Schwarz
- Department of Biochemistry and Functional Proteomics, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Birgit Holzwarth
- Department of Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Bettina Warscheid
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- Department of Biochemistry and Functional Proteomics, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Chris Meisinger
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- ZBMZ Centre for Biochemistry and Molecular Cell Research (Faculty of Medicine), University of Freiburg, Freiburg, Germany
- Institute of Biochemistry and Molecular Biology (Faculty of Medicine), University of Freiburg, Freiburg, Germany
| | - Marcel A. T. M. van Vugt
- Department of Medical Oncology, Cancer Research Center Groningen, University of Groningen, University Medical Center Groningen, GZ Groningen, The Netherlands
| | - Ralf Baumeister
- Department of Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- Research Training Group (RTG) 1104, University of Freiburg, Freiburg, Germany
- ZBMZ Centre for Biochemistry and Molecular Cell Research (Faculty of Medicine), University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Malene Hansen
- Program of Development, Aging and Regeneration, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Kathrin Thedieck
- Department of Pediatrics, Center for Liver, Digestive and Metabolic Diseases, University of Groningen, University Medical Center Groningen, AV Groningen, The Netherlands
- Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
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138
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Wang Y, Mei H, Shao Q, Wang J, Lin Z. Association of ribosomal protein S6 kinase 1 with cellular radiosensitivity of non-small lung cancer. Int J Radiat Biol 2017; 93:581-589. [PMID: 28276898 DOI: 10.1080/09553002.2017.1294273] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Ye Wang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hong Mei
- Department of Pediatric Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qiang Shao
- Critical Care Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Jian Wang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhenyu Lin
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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139
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Enganti R, Cho SK, Toperzer JD, Urquidi-Camacho RA, Cakir OS, Ray AP, Abraham PE, Hettich RL, von Arnim AG. Phosphorylation of Ribosomal Protein RPS6 Integrates Light Signals and Circadian Clock Signals. FRONTIERS IN PLANT SCIENCE 2017; 8:2210. [PMID: 29403507 PMCID: PMC5780430 DOI: 10.3389/fpls.2017.02210] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 12/15/2017] [Indexed: 05/20/2023]
Abstract
The translation of mRNA into protein is tightly regulated by the light environment as well as by the circadian clock. Although changes in translational efficiency have been well documented at the level of mRNA-ribosome loading, the underlying mechanisms are unclear. The reversible phosphorylation of RIBOSOMAL PROTEIN OF THE SMALL SUBUNIT 6 (RPS6) has been known for 40 years, but the biochemical significance of this event remains unclear to this day. Here, we confirm using a clock-deficient strain of Arabidopsis thaliana that RPS6 phosphorylation (RPS6-P) is controlled by the diel light-dark cycle with a peak during the day. Strikingly, when wild-type, clock-enabled, seedlings that have been entrained to a light-dark cycle are placed under free-running conditions, the circadian clock drives a cycle of RPS6-P with an opposite phase, peaking during the subjective night. We show that in wild-type seedlings under a light-dark cycle, the incoherent light and clock signals are integrated by the plant to cause an oscillation in RPS6-P with a reduced amplitude with a peak during the day. Sucrose can stimulate RPS6-P, as seen when sucrose in the medium masks the light response of etiolated seedlings. However, the diel cycles of RPS6-P are observed in the presence of 1% sucrose and in its absence. Sucrose at a high concentration of 3% appears to interfere with the robust integration of light and clock signals at the level of RPS6-P. Finally, we addressed whether RPS6-P occurs uniformly in polysomes, non-polysomal ribosomes and their subunits, and non-ribosomal protein. It is the polysomal RPS6 whose phosphorylation is most highly stimulated by light and repressed by darkness. These data exemplify a striking case of contrasting biochemical regulation between clock signals and light signals. Although the physiological significance of RPS6-P remains unknown, our data provide a mechanistic basis for the future understanding of this enigmatic event.
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Affiliation(s)
- Ramya Enganti
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, United States
| | - Sung Ki Cho
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, United States
| | - Jody D. Toperzer
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, United States
| | - Ricardo A. Urquidi-Camacho
- Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, TN, United States
| | - Ozkan S. Cakir
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, United States
| | - Alexandria P. Ray
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, United States
| | - Paul E. Abraham
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Robert L. Hettich
- Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, TN, United States
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Albrecht G. von Arnim
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, United States
- Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, TN, United States
- *Correspondence: Albrecht G. von Arnim,
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140
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A systems study reveals concurrent activation of AMPK and mTOR by amino acids. Nat Commun 2016; 7:13254. [PMID: 27869123 PMCID: PMC5121333 DOI: 10.1038/ncomms13254] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 09/13/2016] [Indexed: 12/17/2022] Open
Abstract
Amino acids (aa) are not only building blocks for proteins, but also signalling molecules, with the mammalian target of rapamycin complex 1 (mTORC1) acting as a key mediator. However, little is known about whether aa, independently of mTORC1, activate other kinases of the mTOR signalling network. To delineate aa-stimulated mTOR network dynamics, we here combine a computational–experimental approach with text mining-enhanced quantitative proteomics. We report that AMP-activated protein kinase (AMPK), phosphatidylinositide 3-kinase (PI3K) and mTOR complex 2 (mTORC2) are acutely activated by aa-readdition in an mTORC1-independent manner. AMPK activation by aa is mediated by Ca2+/calmodulin-dependent protein kinase kinase β (CaMKKβ). In response, AMPK impinges on the autophagy regulators Unc-51-like kinase-1 (ULK1) and c-Jun. AMPK is widely recognized as an mTORC1 antagonist that is activated by starvation. We find that aa acutely activate AMPK concurrently with mTOR. We show that AMPK under aa sufficiency acts to sustain autophagy. This may be required to maintain protein homoeostasis and deliver metabolite intermediates for biosynthetic processes. mTORC1 is known to mediate the signalling activity of amino acids. Here, the authors combine modelling with experiments and find that amino acids acutely stimulate mTORC2, IRS/PI3K and AMPK, independently of mTORC1. AMPK activation through CaMKKβ sustains autophagy under non-starvation conditions.
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141
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Hansji H, Leung EY, Baguley BC, Finlay GJ, Cameron-Smith D, Figueiredo VC, Askarian-Amiri ME. ZFAS1: a long noncoding RNA associated with ribosomes in breast cancer cells. Biol Direct 2016; 11:62. [PMID: 27871336 PMCID: PMC5117590 DOI: 10.1186/s13062-016-0165-y] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 11/11/2016] [Indexed: 12/20/2022] Open
Abstract
Background Most of the eukaryotic genome is transcribed, yielding a complex network of transcripts including thousands of lncRNAs that generally lack protein coding potential. However, only a small percentage of these molecules has been functionally characterised, and discoveries of specific functions demonstrate layers of complexity. A large percentage of lncRNAs is located in the cytoplasm, associated with ribosomes but the function of the majority of these transcripts is unclear. The current study analyses putative mechanisms of action of the lncRNA species member ZFAS1 that was initially discovered by microarray analysis of murine tissues undergoing mammary gland development. As developmental genes are often deregulated in cancer, here we have studied its function in breast cancer cell lines. Results Using human breast cancer cell lines, ZFAS1 was found to be expressed in all cell lines tested, albeit at different levels of abundance. Following subcellular fractionation, human ZFAS1 was found in both nucleus and cytoplasm (as is the mouse orthologue) in an isoform-independent manner. Sucrose gradients based on velocity sedimentation were utilised to separate the different components of total cell lysate, and surprisingly ZFAS1 was primarily co-localised with light polysomes. Further investigation into ribosome association through subunit dissociation studies showed that ZFAS1 was predominantly associated with the 40S small ribosomal subunit. The expression levels of ZFAS1 and of mRNAs encoding several ribosomal proteins that have roles in ribosome assembly, production and maturation were tightly correlated. ZFAS1 knockdown significantly reduced RPS6 phosphorylation. Conclusion A large number of lncRNAs associate with ribosomes but the function of the majority of these lncRNAs has not been elucidated. The association of the lncRNA ZFAS1 with a subpopulation of ribosomes and the correlation with expression of mRNAs for ribosomal proteins suggest a ribosome-interacting mechanism pertaining to their assembly or biosynthetic activity. ZFAS1 may represent a new class of lncRNAs which associates with ribosomes to regulate their function. Reviewers This article was reviewed by Christine Vande Velde, Nicola Aceto and Haruhiko Siomi. Electronic supplementary material The online version of this article (doi:10.1186/s13062-016-0165-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Herah Hansji
- Auckland Cancer Society Research Centre, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand.,Department of Molecular Medicine and Pathology, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand
| | - Euphemia Y Leung
- Auckland Cancer Society Research Centre, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand.,Department of Molecular Medicine and Pathology, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand
| | - Bruce C Baguley
- Auckland Cancer Society Research Centre, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand
| | - Graeme J Finlay
- Auckland Cancer Society Research Centre, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand.,Department of Molecular Medicine and Pathology, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand
| | - David Cameron-Smith
- The Liggins Institute, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand
| | - Vandre C Figueiredo
- The Liggins Institute, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand
| | - Marjan E Askarian-Amiri
- Auckland Cancer Society Research Centre, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand. .,Department of Molecular Medicine and Pathology, University of Auckland, 85 Park Rd, Grafton, Auckland, 1023, New Zealand.
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142
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Gordeev SA, Bykova TV, Zubova SG, Bystrova OA, Martynova MG, Pospelov VA, Pospelova TV. mTOR kinase inhibitor pp242 causes mitophagy terminated by apoptotic cell death in E1A-Ras transformed cells. Oncotarget 2016; 6:44905-26. [PMID: 26636543 PMCID: PMC4792600 DOI: 10.18632/oncotarget.6457] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 11/28/2015] [Indexed: 01/07/2023] Open
Abstract
mTOR is a critical target for controlling cell cycle progression, senescence and cell death in mammalian cancer cells. Here we studied the role of mTOR-dependent autophagy in implementating the antiprolifrative effect of mTORC1-specific inhibitor rapamycin and ATP-competitive mTOR kinase inhibitor pp242. We carried out a comprehensive analysis of pp242- and rapamycin-induced autophagy in ERas tumor cells. Rapamycin exerts cytostatic effect on ERas tumor cells, thus causing a temporary and reversible cell cycle arrest, activation of non-selective autophagy not accompanied by cell death. The rapamycin-treated cells are able to continue proliferation after drug removal. The ATP-competitive mTORC1/mTORC2 kinase inhibitor pp242 is highly cytotoxic by suppressing the function of mTORC1-4EBP1 axis and mTORC1-dependent phosphorylation of mTORC1 target--ULK1-Ser757 (Atg1). In contrast to rapamycin, pp242 activates the selective autophagy targeting mitochondria (mitophagy). The pp242-induced mitophagy is accompanied by accumulation of LC3 and conversion of LC3-I form to LC3-II. However reduced degradation of p62/SQSTM indicates abnormal flux of autophagic process. According to transmission electron microscopy data, short-term pp242-treated ERas cells exhibit numerous heavily damaged mitochondria, which are included in single membrane-bound autophagic/autolysophagic vacuoles (mitophagy). Despite the lack of typical for apoptosis features, ERas-treated cells with induced mitophagy revealed the activation of caspase 3, 9 and nucleosomal DNA fragmentation. Thus, pp242 activates autophagy with suppressed later stages, leading to impaired recycling and accumulation of dysfunctional mitochondria and cell death. Better understanding of how autophagy determines the fate of a cell--survival or cell death, can help to development of new strategy for cancer therapy.
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Affiliation(s)
- Serguei A Gordeev
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia.,Saint Petersburg State University, St. Petersburg, Russia
| | - Tatiana V Bykova
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia.,Saint Petersburg State University, St. Petersburg, Russia
| | - Svetlana G Zubova
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia
| | - Olga A Bystrova
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia
| | - Marina G Martynova
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia
| | - Valery A Pospelov
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia
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Lu YJ, Swamy KBS, Leu JY. Experimental Evolution Reveals Interplay between Sch9 and Polyploid Stability in Yeast. PLoS Genet 2016; 12:e1006409. [PMID: 27812096 PMCID: PMC5094715 DOI: 10.1371/journal.pgen.1006409] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 10/06/2016] [Indexed: 12/20/2022] Open
Abstract
Polyploidization has crucial impacts on the evolution of different eukaryotic lineages including fungi, plants and animals. Recent genome data suggest that, for many polyploidization events, all duplicated chromosomes are maintained and genome reorganizations occur much later during evolution. However, newly-formed polyploid genomes are intrinsically unstable and often quickly degenerate into aneuploidy or diploidy. The transition between these two states remains enigmatic. In this study, laboratory evolution experiments were conducted to investigate this phenomenon. We show that robust tetraploidy is achieved in evolved yeast cells by increasing the abundance of Sch9—a protein kinase activated by the TORC1 (Target of Rapamycin Complex 1) and other signaling pathways. Overexpressing SCH9, but not TOR1, allows newly-formed tetraploids to exhibit evolved phenotypes and knocking out SCH9 diminishes the evolved phenotypes. Furthermore, when cells were challenged with conditions causing ancestral cells to evolve aneuploidy, tetraploidy was maintained in the evolved lines. Our results reveal a determinant role for Sch9 during the early stage of polyploid evolution. Polyploidy is frequently observed in eukaryotes, including in human liver cells and cancer. Evolutionary studies also suggest that polyploidy has contributed to species diversification and novel adaptation in fungi, plants and animals. However, artificially-constructed polyploids often display chromosome instability and quickly convert to aneuploids. This phenomenon conflicts with observations that many species derived from ancient genome duplications have maintained the extra number of chromosomes following polyploidization. What happened during the early stages of these polyploidy events that stabilized the duplicated genomes? We used laboratory evolution experiments to investigate this process. After being propagated in a rich medium at 23°C for 1000 generations, newly-constructed tetraploid yeast cells had evolved stable genomes. In addition, evolved cells acquired resistance to stresses specific to tetraploids and exhibited a more diploid-like transcriptome profile. Further analyses indicated that Sch9—the functional ortholog of mammalian S6 kinase involved in protein homeostasis, G1 progression, stress response and nutrient signaling—contributed to the evolved phenotypes. Evolved cells increased the protein abundance and stability of Sch9. Reconstitution experiments showed that overexpression of SCH9 enabled ancestral cells to display the evolved phenotypes and eliminating SCH9 diminished the evolved phenotypes. Finally, we show that evolved cells were able to maintain their genomes even under a condition that causes newly-formed tetraploids to evolve aneuploidy. Our results reveal that at the early stages after genome duplication, stable polyploidy can be achieved by fine-tuning a conserved key regulator coordinating multiple cellular processes.
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Affiliation(s)
- Yi-Jin Lu
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | | | - Jun-Yi Leu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- * E-mail:
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144
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mTORC1 signalling and eIF4E/4E-BP1 translation initiation factor stoichiometry influence recombinant protein productivity from GS-CHOK1 cells. Biochem J 2016; 473:4651-4664. [PMID: 27760840 PMCID: PMC5147049 DOI: 10.1042/bcj20160845] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 10/17/2016] [Accepted: 10/19/2016] [Indexed: 12/14/2022]
Abstract
Many protein-based biotherapeutics are produced in cultured Chinese hamster ovary (CHO) cell lines. Recent reports have demonstrated that translation of recombinant mRNAs and global control of the translation machinery via mammalian target of rapamycin (mTOR) signalling are important determinants of the amount and quality of recombinant protein such cells can produce. mTOR complex 1 (mTORC1) is a master regulator of cell growth/division, ribosome biogenesis and protein synthesis, but the relationship between mTORC1 signalling, cell growth and proliferation and recombinant protein yields from mammalian cells, and whether this master regulating signalling pathway can be manipulated to enhance cell biomass and recombinant protein production (rPP) are not well explored. We have investigated mTORC1 signalling and activity throughout batch culture of a panel of sister recombinant glutamine synthetase-CHO cell lines expressing different amounts of a model monoclonal IgG4, to evaluate the links between mTORC1 signalling and cell proliferation, autophagy, recombinant protein expression, global protein synthesis and mRNA translation initiation. We find that the expression of the mTORC1 substrate 4E-binding protein 1 (4E-BP1) fluctuates throughout the course of cell culture and, as expected, that the 4E-BP1 phosphorylation profiles change across the culture. Importantly, we find that the eIF4E/4E-BP1 stoichiometry positively correlates with cell productivity. Furthermore, eIF4E amounts appear to be co-regulated with 4E-BP1 amounts. This may reflect a sensing of either change at the mRNA level as opposed to the protein level or the fact that the phosphorylation status, as well as the amount of 4E-BP1 present, is important in the co-regulation of eIF4E and 4E-BP1.
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145
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McGlory C, Devries MC, Phillips SM. Skeletal muscle and resistance exercise training; the role of protein synthesis in recovery and remodeling. J Appl Physiol (1985) 2016; 122:541-548. [PMID: 27742803 DOI: 10.1152/japplphysiol.00613.2016] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 10/04/2016] [Accepted: 10/05/2016] [Indexed: 12/22/2022] Open
Abstract
Exercise results in the rapid remodeling of skeletal muscle. This process is underpinned by acute and chronic changes in both gene and protein synthesis. In this short review we provide a brief summary of our current understanding regarding how exercise influences these processes as well as the subsequent impact on muscle protein turnover and resultant shift in muscle phenotype. We explore concepts of ribosomal biogenesis and the potential role of increased translational capacity vs. translational efficiency in contributing to muscular hypertrophy. We also examine whether high-intensity sprinting-type exercise promotes changes in protein turnover that lead to hypertrophy or merely a change in mitochondrial content. Finally, we propose novel areas for future study that will fill existing knowledge gaps in the fields of translational research and exercise science.
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Affiliation(s)
- Chris McGlory
- Department of Kinesiology, McMaster University, Ontario, Canada
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Zhang X, Fu LJ, Liu XQ, Hu ZY, Jiang Y, Gao RF, Feng Q, Lan X, Geng YQ, Chen XM, He JL, Wang YX, Ding YB. nm23 regulates decidualization through the PI3K-Akt-mTOR signaling pathways in mice and humans. Hum Reprod 2016; 31:2339-51. [PMID: 27604954 DOI: 10.1093/humrep/dew191] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 07/08/2016] [Indexed: 12/22/2022] Open
Abstract
STUDY QUESTION Does nm23 have functional significance in decidualization in mice and humans? SUMMARY ANSWER nm23 affects decidualization via the phosphoinositide 3 kinase/mammalian target of rapamycin (PI3K-Akt-mTOR) signaling pathways in mouse endometrial stromal cells (ESCs; mESCs) and human ESCs. WHAT IS KNOWN ALREADY The function of nm23 in suppressing metastasis has been demonstrated in a variety of cancer types. nm23 also participates in the control of DNA replication and cell proliferation and differentiation. STUDY DESIGN, SIZE AND DURATION We first analyzed the expression profile of nm23 in mice during early pregnancy (n = 6/group), pseudopregnancy (n = 6/group) and artificial decidualization (n = 6/group) and in humans during the menstrual cycle phases and the first trimester. We then used primary cultured mESCs and a human ESC line, T-HESC, to explore the hormonal regulation of nm23 and the roles of nm23 in in vitro decidualization, and as a possible mediator of downstream PI3K-Akt-mTOR signaling pathways. PARTICIPANTS/MATERIALS, SETTINGS AND METHODS We evaluated the dynamic expression of nm23 in mice and humans using immunohistochemistry, western blot and real-time quantitative RT-PCR (RT-qPCR). Regulation of nm23 by steroid hormones was investigated in isolated primary mESCs and T-HESCs by western blot. The effect of nm23 knockdown (using siRNA) on ESC proliferation was analyzed by 5-ethynyl-2'-deoxyuridine staining (EdU) and proliferating cell nuclear antigen protein (PCNA) expression. The influence of nm23 expression on the differentiation of ESCs was determined by RT-qPCR using the mouse differentiation markers decidual/trophoblast PRL-related protein (dtprp, also named prl8a2) and prolactin family 3 subfamily c member 1 (prl3c1) and the human differentiation markers insulin-like growth factor binding protein 1 (IGFBP1) and prolactin (PRL). The effects of nm23 siRNA (si-nm23) and the PI3K inhibitor LY294002 on the downstream effects of nm23 on the PI3K-Akt-mTOR signaling pathway were estimated by western blot. MAIN RESULTS AND THE ROLE OF CHANCE NM23-M1 was specifically expressed in the decidual zone during early pregnancy and in artificially induced deciduoma, and NM23-H1 was strongly expressed in human first trimester decidua. The expression of nm23 was upregulated by oestradiol and progesterone (P < 0.05 versus control) in vitro in mESCs and T-HESC, and this was inhibited by their respective receptor antagonists, ICI 182,780 and RU486. Mouse and human nm23 knockdown decreased ESC proliferation and differentiation (P < 0.05 versus control). The PI3K-Akt-mTOR signaling pathways were downstream mediators of nm23 in mESCs and T-HESCs decidualization. LIMITATIONS AND REASONS FOR CAUTION Whether the nm23 regulates decidualization via the activation of AMPK, RAS, PKA, STAT3 or other signaling molecules remains to be determined. The role of nm23 in decidualization was tested in vitro only. WIDER IMPLICATIONS OF THE FINDINGS Results demonstrate that nm23 plays a vital role in decidualization in mice and humans and that nm23 gene expression is hormonally regulated. The downregulation of nm23 in decidua during the first trimester may be associated with infertility in women. STUDY FUNDING/COMPETING INTERESTS This study was supported by the National Natural Science Foundation of China (grant nos. 81370731, 31571551 and 31571190), the Science and Technology Project of Chongqing Education Committee (KJ130309), open funding by the Chongqing Institute for Family Planning (1201) and the Excellent Young Scholars of Chongqing Medical University (CQYQ201302). The authors have no conflicts of interest to declare.
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Affiliation(s)
- Xue Zhang
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, P. R. China
| | - Li-Juan Fu
- School of Traditional Chinese Medicine, Chongqing Medical University, Chongqing 400016, P. R. China
| | - Xue-Qing Liu
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, P. R. China
| | - Zhuo-Ying Hu
- Department of Obstetrics and Gynecology, the First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, P. R. China
| | - Yu Jiang
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh 15261, PA, USA
| | - Ru-Fei Gao
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, P. R. China
| | - Qian Feng
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, P. R. China
| | - Xi Lan
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, P. R. China
| | - Yan-Qing Geng
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, P. R. China
| | - Xue-Mei Chen
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, P. R. China
| | - Jun-Lin He
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, P. R. China
| | - Ying-Xiong Wang
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, P. R. China
| | - Yu-Bin Ding
- Laboratory of Reproductive Biology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, P. R. China
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Camera DM, Smiles WJ, Hawley JA. Exercise-induced skeletal muscle signaling pathways and human athletic performance. Free Radic Biol Med 2016; 98:131-143. [PMID: 26876650 DOI: 10.1016/j.freeradbiomed.2016.02.007] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 01/28/2016] [Accepted: 02/03/2016] [Indexed: 12/18/2022]
Abstract
Skeletal muscle is a highly malleable tissue capable of altering its phenotype in response to external stimuli including exercise. This response is determined by the mode, (endurance- versus resistance-based), volume, intensity and frequency of exercise performed with the magnitude of this response-adaptation the basis for enhanced physical work capacity. However, training-induced adaptations in skeletal muscle are variable and unpredictable between individuals. With the recent application of molecular techniques to exercise biology, there has been a greater understanding of the multiplicity and complexity of cellular networks involved in exercise responses. This review summarizes the molecular and cellular events mediating adaptation processes in skeletal muscle in response to exercise. We discuss established and novel cell signaling proteins mediating key physiological responses associated with enhanced exercise performance and the capacity for reactive oxygen and nitrogen species to modulate training adaptation responses. We also examine the molecular bases underpinning heterogeneous responses to resistance and endurance exercise and the dissociation between molecular 'markers' of training adaptation and subsequent exercise performance.
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Affiliation(s)
- Donny M Camera
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Vic. 3065, Australia
| | - William J Smiles
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Vic. 3065, Australia
| | - John A Hawley
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Vic. 3065, Australia; Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool L3 3AF, United Kingdom.
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148
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Uusküla-Reimand L, Hou H, Samavarchi-Tehrani P, Rudan MV, Liang M, Medina-Rivera A, Mohammed H, Schmidt D, Schwalie P, Young EJ, Reimand J, Hadjur S, Gingras AC, Wilson MD. Topoisomerase II beta interacts with cohesin and CTCF at topological domain borders. Genome Biol 2016; 17:182. [PMID: 27582050 PMCID: PMC5006368 DOI: 10.1186/s13059-016-1043-8] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 08/10/2016] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Type II DNA topoisomerases (TOP2) regulate DNA topology by generating transient double stranded breaks during replication and transcription. Topoisomerase II beta (TOP2B) facilitates rapid gene expression and functions at the later stages of development and differentiation. To gain new insight into the genome biology of TOP2B, we used proteomics (BioID), chromatin immunoprecipitation, and high-throughput chromosome conformation capture (Hi-C) to identify novel proximal TOP2B protein interactions and characterize the genomic landscape of TOP2B binding at base pair resolution. RESULTS Our human TOP2B proximal protein interaction network included members of the cohesin complex and nucleolar proteins associated with rDNA biology. TOP2B associates with DNase I hypersensitivity sites, allele-specific transcription factor (TF) binding, and evolutionarily conserved TF binding sites on the mouse genome. Approximately half of all CTCF/cohesion-bound regions coincided with TOP2B binding. Base pair resolution ChIP-exo mapping of TOP2B, CTCF, and cohesin sites revealed a striking structural ordering of these proteins along the genome relative to the CTCF motif. These ordered TOP2B-CTCF-cohesin sites flank the boundaries of topologically associating domains (TADs) with TOP2B positioned externally and cohesin internally to the domain loop. CONCLUSIONS TOP2B is positioned to solve topological problems at diverse cis-regulatory elements and its occupancy is a highly ordered and prevalent feature of CTCF/cohesin binding sites that flank TADs.
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Affiliation(s)
- Liis Uusküla-Reimand
- Genetics and Genome Biology Program, SickKids Research Institute, Toronto, ON Canada
- Department of Gene Technology, Tallinn University of Technology, Tallinn, Estonia
| | - Huayun Hou
- Genetics and Genome Biology Program, SickKids Research Institute, Toronto, ON Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON Canada
| | | | - Matteo Vietri Rudan
- Research Department of Cancer Biology, Cancer Institute, University College London, London, UK
| | - Minggao Liang
- Genetics and Genome Biology Program, SickKids Research Institute, Toronto, ON Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON Canada
| | - Alejandra Medina-Rivera
- Genetics and Genome Biology Program, SickKids Research Institute, Toronto, ON Canada
- Present address: International Laboratory for Research in Human Genomics, Universidad Nacional Autónoma de México, Juriquilla, Querétaro Mexico
| | - Hisham Mohammed
- Cancer Research UK, Cambridge Institute, University of Cambridge, Cambridge, UK
- Present address: The Babraham Institute, Cambridge, UK
| | - Dominic Schmidt
- Cancer Research UK, Cambridge Institute, University of Cambridge, Cambridge, UK
- Present address: Syncona Partners LLP, London, UK
| | - Petra Schwalie
- European Molecular Biology Laboratory, European Bioinformatics Institute, Cambridge, UK
- Present address: Laboratory of Systems Biology and Genetics, Lausanne, Switzerland
| | - Edwin J. Young
- Genetics and Genome Biology Program, SickKids Research Institute, Toronto, ON Canada
| | - Jüri Reimand
- Ontario Institute for Cancer Research, Toronto, ON Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON Canada
| | - Suzana Hadjur
- Research Department of Cancer Biology, Cancer Institute, University College London, London, UK
| | - Anne-Claude Gingras
- Department of Molecular Genetics, University of Toronto, Toronto, ON Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON Canada
| | - Michael D. Wilson
- Genetics and Genome Biology Program, SickKids Research Institute, Toronto, ON Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON Canada
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Abstract
The mammalian target of rapamycin, mTOR, plays key roles in cell growth and proliferation, acting at the catalytic subunit of two protein kinase complexes: mTOR complexes 1 and 2 (mTORC1/2). mTORC1 signaling is switched on by several oncogenic signaling pathways and is accordingly hyperactive in the majority of cancers. Inhibiting mTORC1 signaling has therefore attracted great attention as an anti-cancer therapy. However, progress in using inhibitors of mTOR signaling as therapeutic agents in oncology has been limited by a number of factors, including the fact that the classic mTOR inhibitor, rapamycin, inhibits only some of the effects of mTOR; the existence of several feedback loops; and the crucial importance of mTOR in normal physiology.
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Affiliation(s)
- Jianling Xie
- Nutrition and Metabolism, South Australian Health and Medical research Institute, Adelaide, SA, Australia
| | - Xuemin Wang
- Nutrition and Metabolism, South Australian Health and Medical research Institute, Adelaide, SA, Australia; School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Christopher G Proud
- Nutrition and Metabolism, South Australian Health and Medical research Institute, Adelaide, SA, Australia; School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
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150
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Mazelin L, Panthu B, Nicot AS, Belotti E, Tintignac L, Teixeira G, Zhang Q, Risson V, Baas D, Delaune E, Derumeaux G, Taillandier D, Ohlmann T, Ovize M, Gangloff YG, Schaeffer L. mTOR inactivation in myocardium from infant mice rapidly leads to dilated cardiomyopathy due to translation defects and p53/JNK-mediated apoptosis. J Mol Cell Cardiol 2016; 97:213-25. [DOI: 10.1016/j.yjmcc.2016.04.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 04/05/2016] [Accepted: 04/12/2016] [Indexed: 10/21/2022]
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