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Lambies G, Lee SW, Duong-Polk K, Aza-Blanc P, Maganti S, Dawson DW, Commisso C. Cell polarity proteins promote macropinocytosis in response to metabolic stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.16.575943. [PMID: 38293142 PMCID: PMC10827152 DOI: 10.1101/2024.01.16.575943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Macropinocytosis has emerged as a nutrient-scavenging pathway that cancer cells exploit to survive the nutrient-deprived conditions of the tumor microenvironment. Cancer cells are especially reliant on glutamine for their survival, and in pancreatic ductal adenocarcinoma (PDAC) cells, glutamine deficiency can enhance the stimulation of macropinocytosis, allowing the cells to escape metabolic stress through the production of extracellular-protein-derived amino acids. Here, we identify the atypical protein kinase C (aPKC) enzymes, PKCζ and PKCι as novel regulators of macropinocytosis. In normal epithelial cells, aPKCs are known to regulate cell polarity in association with the scaffold proteins Par3 and Par6, controlling the function of several targets, including the Par1 kinases. In PDAC cells, we identify that each of these cell polarity proteins are required for glutamine stress-induced macropinocytosis. Mechanistically, we find that the aPKCs are regulated by EGFR signaling or by the transcription factor CREM to promote the relocation of Par3 to microtubules, facilitating macropinocytosis in a dynein-dependent manner. Importantly, we determine that cell fitness impairment caused by aPKC depletion is rescued by the restoration of macropinocytosis and that aPKCs support PDAC growth in vivo. These results identify a previously unappreciated role for cell polarity proteins in the regulation of macropinocytosis and provide a better understanding of the mechanistic underpinnings that control macropinocytic uptake in the context of metabolic stress.
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2
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Ragupathi A, Kim C, Jacinto E. The mTORC2 signaling network: targets and cross-talks. Biochem J 2024; 481:45-91. [PMID: 38270460 PMCID: PMC10903481 DOI: 10.1042/bcj20220325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/29/2023] [Accepted: 12/18/2023] [Indexed: 01/26/2024]
Abstract
The mechanistic target of rapamycin, mTOR, controls cell metabolism in response to growth signals and stress stimuli. The cellular functions of mTOR are mediated by two distinct protein complexes, mTOR complex 1 (mTORC1) and mTORC2. Rapamycin and its analogs are currently used in the clinic to treat a variety of diseases and have been instrumental in delineating the functions of its direct target, mTORC1. Despite the lack of a specific mTORC2 inhibitor, genetic studies that disrupt mTORC2 expression unravel the functions of this more elusive mTOR complex. Like mTORC1 which responds to growth signals, mTORC2 is also activated by anabolic signals but is additionally triggered by stress. mTORC2 mediates signals from growth factor receptors and G-protein coupled receptors. How stress conditions such as nutrient limitation modulate mTORC2 activation to allow metabolic reprogramming and ensure cell survival remains poorly understood. A variety of downstream effectors of mTORC2 have been identified but the most well-characterized mTORC2 substrates include Akt, PKC, and SGK, which are members of the AGC protein kinase family. Here, we review how mTORC2 is regulated by cellular stimuli including how compartmentalization and modulation of complex components affect mTORC2 signaling. We elaborate on how phosphorylation of its substrates, particularly the AGC kinases, mediates its diverse functions in growth, proliferation, survival, and differentiation. We discuss other signaling and metabolic components that cross-talk with mTORC2 and the cellular output of these signals. Lastly, we consider how to more effectively target the mTORC2 pathway to treat diseases that have deregulated mTOR signaling.
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Affiliation(s)
- Aparna Ragupathi
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, U.S.A
| | - Christian Kim
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, U.S.A
| | - Estela Jacinto
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, U.S.A
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3
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Khalil MI, Ali MM, Holail J, Houssein M. Growth or death? Control of cell destiny by mTOR and autophagy pathways. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 185:39-55. [PMID: 37944568 DOI: 10.1016/j.pbiomolbio.2023.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/08/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023]
Abstract
One of the central regulators of cell growth, proliferation, and metabolism is the mammalian target of rapamycin, mTOR, which exists in two structurally and functionally different complexes: mTORC1 and mTORC2; unlike m TORC2, mTORC1 is activated in response to the sufficiency of nutrients and is inhibited by rapamycin. mTOR complexes have critical roles not only in protein synthesis, gene transcription regulation, proliferation, tumor metabolism, but also in the regulation of the programmed cell death mechanisms such as autophagy and apoptosis. Autophagy is a conserved catabolic mechanism in which damaged molecules are recycled in response to nutrient starvation. Emerging evidence indicates that the mTOR signaling pathway is frequently activated in tumors. In addition, dysregulation of autophagy was associated with the development of a variety of human diseases, such as cancer and aging. Since mTOR can inhibit the induction of the autophagic process from the early stages of autophagosome formation to the late stage of lysosome degradation, the use of mTOR inhibitors to regulate autophagy could be considered a potential therapeutic option. The present review sheds light on the mTOR and autophagy signaling pathways and the mechanisms of regulation of mTOR-autophagy.
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Affiliation(s)
- Mahmoud I Khalil
- Department of Biological Sciences, Faculty of Science, Beirut Arab University, Beirut, 11072809, Lebanon; Molecular Biology Unit, Department of Zoology, Faculty of Science, Alexandria University, Alexandria, 21511, Egypt.
| | - Mohamad M Ali
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, SE-751 23, Uppsala, Sweden.
| | - Jasmine Holail
- Department of Biochemistry and Molecular Medicine, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia; Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom.
| | - Marwa Houssein
- Department of Biological Sciences, Faculty of Science, Beirut Arab University, Beirut, 11072809, Lebanon.
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4
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Frappaolo A, Giansanti MG. Using Drosophila melanogaster to Dissect the Roles of the mTOR Signaling Pathway in Cell Growth. Cells 2023; 12:2622. [PMID: 37998357 PMCID: PMC10670727 DOI: 10.3390/cells12222622] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/10/2023] [Accepted: 11/11/2023] [Indexed: 11/25/2023] Open
Abstract
The evolutionarily conserved target of rapamycin (TOR) serine/threonine kinase controls eukaryotic cell growth, metabolism and survival by integrating signals from the nutritional status and growth factors. TOR is the catalytic subunit of two distinct functional multiprotein complexes termed mTORC1 (mechanistic target of rapamycin complex 1) and mTORC2, which phosphorylate a different set of substrates and display different physiological functions. Dysregulation of TOR signaling has been involved in the development and progression of several disease states including cancer and diabetes. Here, we highlight how genetic and biochemical studies in the model system Drosophila melanogaster have been crucial to identify the mTORC1 and mTORC2 signaling components and to dissect their function in cellular growth, in strict coordination with insulin signaling. In addition, we review new findings that involve Drosophila Golgi phosphoprotein 3 in regulating organ growth via Rheb-mediated activation of mTORC1 in line with an emerging role for the Golgi as a major hub for mTORC1 signaling.
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Affiliation(s)
- Anna Frappaolo
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, 00185 Roma, Italy
| | - Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, 00185 Roma, Italy
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5
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Prosseda PP, Dannewitz Prosseda S, Tran M, Liton PB, Sun Y. Crosstalk between the mTOR pathway and primary cilia in human diseases. Curr Top Dev Biol 2023; 155:1-37. [PMID: 38043949 PMCID: PMC11227733 DOI: 10.1016/bs.ctdb.2023.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Autophagy is a fundamental catabolic process whereby excessive or damaged cytoplasmic components are degraded through lysosomes to maintain cellular homeostasis. Studies of mTOR signaling have revealed that mTOR controls biomass generation and metabolism by modulating key cellular processes, including protein synthesis and autophagy. Primary cilia, the assembly of which depends on kinesin molecular motors, serve as sensory organelles and signaling platforms. Given these pathways' central role in maintaining cellular and physiological homeostasis, a connection between mTOR and primary cilia signaling is starting to emerge in a variety of diseases. In this review, we highlight recent advances in our understanding of the complex crosstalk between the mTOR pathway and cilia and discuss its function in the context of related diseases.
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Affiliation(s)
- Philipp P Prosseda
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
| | | | - Matthew Tran
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
| | - Paloma B Liton
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, United States
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States; Palo Alto Veterans Administration Medical Center, Palo Alto, CA, United States.
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6
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Hu W, Zhang Y, Ning J, Li M, Tang Y, Li L, Cheng F, Yu W. Anti-tumor effect of AZD8055 against bladder cancer and bladder cancer-associated macrophages. Heliyon 2023; 9:e14272. [PMID: 36938467 PMCID: PMC10020012 DOI: 10.1016/j.heliyon.2023.e14272] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 02/22/2023] [Accepted: 02/28/2023] [Indexed: 03/08/2023] Open
Abstract
The increased activity of the mTOR pathway in bladder cancer has been extensively studied, but no satisfactory mTOR inhibitor has been found in bladder cancer. The role of AZD8055, a second-generation mTOR inhibitor, has not been reported in bladder cancer. Herein, we investigated the effects of AZD8055 on bladder cells and their interaction with macrophages in vivo and in vitro. In four bladder cancer cell lines, the phosphorylation of mTOR, AKT and S6K1 was suppressed by AZD8055. AZD8055 inhibited proliferation and induced G1 cell-cycle arrest and apoptosis of bladder cancer cells in a concentration-dependent manner. AZD8055 also inhibits the migration and invasion of bladder cancer cells by blocking EMT and MMP9. In addition, AZD8055 inhibited chemotaxis and M2 phenotype of macrophage after co-culture with bladder cancer cells. These anti-tumor effects of AZD8055 were verified in vivo. Our findings collectively demonstrated that low-dose AZD8055 induces cytotoxicity and apoptosis, and inhibits the Akt/mTOR activation, invasion and migration of bladder cancer. These findings also demonstrate that AZD8055 partially blocked the interactions of bladder cancer cells and macrophages. In conclusion, AZD8055 is a promising mTOR inhibitor for bladder cancer.
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Sun Y, Wang H, Qu T, Luo J, An P, Ren F, Luo Y, Li Y. mTORC2: a multifaceted regulator of autophagy. Cell Commun Signal 2023; 21:4. [PMID: 36604720 PMCID: PMC9814435 DOI: 10.1186/s12964-022-00859-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/06/2022] [Indexed: 01/06/2023] Open
Abstract
Autophagy is a multi-step catabolic process that delivers cellular components to lysosomes for degradation and recycling. The dysregulation of this precisely controlled process disrupts cellular homeostasis and leads to many pathophysiological conditions. The mechanistic target of rapamycin (mTOR) is a central nutrient sensor that integrates growth signals with anabolism to fulfil biosynthetic and bioenergetic requirements. mTOR nucleates two distinct evolutionarily conserved complexes (mTORC1 and mTORC2). However, only mTORC1 is acutely inhibited by rapamycin. Consequently, mTORC1 is a well characterized regulator of autophagy. While less is known about mTORC2, the availability of acute small molecule inhibitors and multiple genetic models has led to increased understanding about the role of mTORC2 in autophagy. Emerging evidence suggests that the regulation of mTORC2 in autophagy is mainly through its downstream effector proteins, and is variable under different conditions and cellular contexts. Here, we review recent advances that describe a role for mTORC2 in this catabolic process, and propose that mTORC2 could be a potential clinical target for the treatment of autophagy-related diseases. Video abstract.
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Affiliation(s)
- Yanan Sun
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083 China
| | - Huihui Wang
- grid.411734.40000 0004 1798 5176College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, 730070 China
| | - Taiqi Qu
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083 China
| | - Junjie Luo
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083 China
| | - Peng An
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083 China
| | - Fazheng Ren
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083 China
| | - Yongting Luo
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083 China
| | - Yixuan Li
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083 China
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8
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Scalia P, Williams SJ, Fujita-Yamaguchi Y, Giordano A. Cell cycle control by the insulin-like growth factor signal: at the crossroad between cell growth and mitotic regulation. Cell Cycle 2023; 22:1-37. [PMID: 36005738 PMCID: PMC9769454 DOI: 10.1080/15384101.2022.2108117] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
In proliferating cells and tissues a number of checkpoints (G1/S and G2/M) preceding cell division (M-phase) require the signal provided by growth factors present in serum. IGFs (I and II) have been demonstrated to constitute key intrinsic components of the peptidic active fraction of mammalian serum. In vivo genetic ablation studies have shown that the cellular signal triggered by the IGFs through their cellular receptors represents a non-replaceable requirement for cell growth and cell cycle progression. Retroactive and current evaluation of published literature sheds light on the intracellular circuitry activated by these factors providing us with a better picture of the pleiotropic mechanistic actions by which IGFs regulate both cell size and mitogenesis under developmental growth as well as in malignant proliferation. The present work aims to summarize the cumulative knowledge learned from the IGF ligands/receptors and their intracellular signaling transducers towards control of cell size and cell-cycle with particular focus to their actionable circuits in human cancer. Furthermore, we bring novel perspectives on key functional discriminants of the IGF growth-mitogenic pathway allowing re-evaluation on some of its signal components based upon established evidences.
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Affiliation(s)
- Pierluigi Scalia
- ISOPROG-Somatolink EPFP Research Network, Philadelphia, PA, USA, Caltanissetta, Italy,CST, Biology, Sbarro Institute for Cancer Research and Molecular Medicine, Temple University, Philadelphia, PA, United states,CONTACT Pierluigi Scalia ISOPROG-Somatolink EPFP Research Network, Philadelphia, PA9102, USA
| | - Stephen J Williams
- ISOPROG-Somatolink EPFP Research Network, Philadelphia, PA, USA, Caltanissetta, Italy,CST, Biology, Sbarro Institute for Cancer Research and Molecular Medicine, Temple University, Philadelphia, PA, United states
| | - Yoko Fujita-Yamaguchi
- Arthur Riggs Diabetes & Metabolism Research Institute, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Antonio Giordano
- ISOPROG-Somatolink EPFP Research Network, Philadelphia, PA, USA, Caltanissetta, Italy,School of Medical Biotechnology, University of Siena, Italy
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9
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Baskaran P, Mihaylov SR, Vinsland E, Shah K, Granat L, Ultanir SK, Tee AR, Murn J, Bateman JM. Phosphorylation of the novel mTOR substrate Unkempt regulates cellular morphogenesis. J Biol Chem 2023; 299:102788. [PMID: 36509146 PMCID: PMC9852543 DOI: 10.1016/j.jbc.2022.102788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 11/24/2022] [Accepted: 11/25/2022] [Indexed: 12/13/2022] Open
Abstract
Mechanistic target of rapamycin (mTOR) is a protein kinase that integrates multiple inputs to regulate anabolic cellular processes. For example, mTOR complex 1 (mTORC1) has key functions in growth control, autophagy, and metabolism. However, much less is known about the signaling components that act downstream of mTORC1 to regulate cellular morphogenesis. Here, we show that the RNA-binding protein Unkempt, a key regulator of cellular morphogenesis, is a novel substrate of mTORC1. We show that Unkempt phosphorylation is regulated by nutrient levels and growth factors via mTORC1. To analyze Unkempt phosphorylation, we immunoprecipitated Unkempt from cells in the presence or the absence of the mTORC1 inhibitor rapamycin and used mass spectrometry to identify mTORC1-dependent phosphorylated residues. This analysis showed that mTORC1-dependent phosphorylation is concentrated in a serine-rich intrinsically disordered region in the C-terminal half of Unkempt. We also found that Unkempt physically interacts with and is directly phosphorylated by mTORC1 through binding to the regulatory-associated protein of mTOR, Raptor. Furthermore, analysis in the developing brain of mice lacking TSC1 expression showed that phosphorylation of Unkempt is mTORC1 dependent in vivo. Finally, mutation analysis of key serine/threonine residues in the serine-rich region indicates that phosphorylation inhibits the ability of Unkempt to induce a bipolar morphology. Phosphorylation within this serine-rich region thus profoundly affects the ability of Unkempt to regulate cellular morphogenesis. Taken together, our findings reveal a novel molecular link between mTORC1 signaling and cellular morphogenesis.
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Affiliation(s)
- Pranetha Baskaran
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London, UK
| | - Simeon R Mihaylov
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London, UK; Kinases and Brain Development Lab, The Francis Crick Institute, London, UK
| | - Elin Vinsland
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London, UK; Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Kriti Shah
- Department of Biochemistry, University of California, Riverside, California, USA
| | - Lucy Granat
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London, UK
| | - Sila K Ultanir
- Kinases and Brain Development Lab, The Francis Crick Institute, London, UK
| | - Andrew R Tee
- Cancer and Genetics Building, Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park Way, Cardiff, UK
| | - Jernej Murn
- Department of Biochemistry, University of California, Riverside, California, USA.
| | - Joseph M Bateman
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London, UK.
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10
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Huang J, Chen L, Wu J, Ai D, Zhang JQ, Chen TG, Wang L. Targeting the PI3K/AKT/mTOR Signaling Pathway in the Treatment of Human Diseases: Current Status, Trends, and Solutions. J Med Chem 2022; 65:16033-16061. [PMID: 36503229 DOI: 10.1021/acs.jmedchem.2c01070] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is one of the most important intracellular pathways involved in cell proliferation, growth, differentiation, and survival. Therefore, this route is a prospective biological target for treating various human diseases, such as tumors, neurodegenerative diseases, pulmonary fibrosis, and diabetes. An increasing number of clinical studies emphasize the necessity of developing novel molecules targeting the PI3K/AKT/mTOR pathway. This review focuses on recent advances in ATP-competitive inhibitors, allosteric inhibitors, covalent inhibitors, and proteolysis-targeting chimeras against the PI3K/AKT/mTOR pathway, and highlights possible solutions for overcoming the toxicities and acquired drug resistance of currently available drugs. We also provide recommendations for the future design and development of promising drugs targeting this pathway.
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Affiliation(s)
- Jindi Huang
- Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, Joint International Research Laboratory of Synthetic Biology and Medicine, Guangdong Provincial Engineering and Technology Research Center of Biopharmaceuticals, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Liye Chen
- Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, Joint International Research Laboratory of Synthetic Biology and Medicine, Guangdong Provincial Engineering and Technology Research Center of Biopharmaceuticals, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Jiangxia Wu
- Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, Joint International Research Laboratory of Synthetic Biology and Medicine, Guangdong Provincial Engineering and Technology Research Center of Biopharmaceuticals, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Daiqiao Ai
- Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, Joint International Research Laboratory of Synthetic Biology and Medicine, Guangdong Provincial Engineering and Technology Research Center of Biopharmaceuticals, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Ji-Quan Zhang
- College of Pharmacy, Guizhou Medical University, Guiyang 550004, China
| | - Tie-Gen Chen
- Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Room 109, Building C, SSIP Healthcare and Medicine Demonstration Zone, Zhongshan Tsuihang New District, Zhongshan, Guangdong 528400, China
| | - Ling Wang
- Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, Joint International Research Laboratory of Synthetic Biology and Medicine, Guangdong Provincial Engineering and Technology Research Center of Biopharmaceuticals, School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
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11
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Yu Z, Chen J, Takagi E, Wang F, Saha B, Liu X, Joubert LM, Gleason CE, Jin M, Li C, Nowotny C, Agard D, Cheng Y, Pearce D. Interactions between mTORC2 core subunits Rictor and mSin1 dictate selective and context-dependent phosphorylation of substrate kinases SGK1 and Akt. J Biol Chem 2022; 298:102288. [PMID: 35926713 PMCID: PMC9440446 DOI: 10.1016/j.jbc.2022.102288] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 12/02/2022] Open
Abstract
Mechanistic target of rapamycin complex 2 (mTORC2) is a multi-subunit kinase complex, central to multiple essential signaling pathways. Two core subunits, Rictor and mSin1, distinguish it from the related mTORC1 and support context-dependent phosphorylation of its substrates. mTORC2 structures have been determined previously; however, important questions remain, particularly regarding the structural determinants mediating substrate specificity and context-dependent activity. Here, we used cryo-EM to obtain high-resolution structures of the human mTORC2 apo-complex in the presence of substrates Akt and SGK1. Using functional assays, we then tested predictions suggested by substrate-induced structural changes in mTORC2. For the first time, we visualized in the apo-state the side chain interactions between Rictor and mTOR that sterically occlude recruitment of mTORC1 substrates and confer resistance to the mTORC1 inhibitor rapamycin. Also in the apo-state, we observed that mSin1 formed extensive contacts with Rictor via a pair of short α-helices nestled between two Rictor helical repeat clusters, as well as by an extended strand that makes multiple weak contacts with Rictor helical cluster 1. In co-complex structures, we found that SGK1, but not Akt, markedly altered the conformation of the mSin1 N-terminal extended strand, disrupting multiple weak interactions while inducing a large rotation of mSin1 residue Arg-83, which then interacts with a patch of negatively charged residues within Rictor. Finally, we demonstrate mutation of Arg-83 to Ala selectively disrupts mTORC2-dependent phosphorylation of SGK1, but not of Akt, supporting context-dependent substrate selection. These findings provide new structural and functional insights into mTORC2 specificity and context-dependent activity.
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Affiliation(s)
- Zanlin Yu
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Junliang Chen
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA
| | - Enzo Takagi
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA
| | - Feng Wang
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Bidisha Saha
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA
| | - Xi Liu
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - Lydia-Marie Joubert
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California, USA
| | - Catherine E Gleason
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA
| | - Mingliang Jin
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Chengmin Li
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Carlos Nowotny
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - David Agard
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Yifan Cheng
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA; Howard Hughes Medical Institute, University of California San Francisco, San Francisco, California, USA
| | - David Pearce
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA.
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12
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Cai X, Li H, Wang M, Chu E, Wei N, Lin J, Hu Y, Dai J, Chen A, Zheng H, Zhang Q, Zhong Y, Chang R, Wu S, Xiao Y, Liu C. mTOR Participates in the Formation, Maintenance, and Function of Memory CD8 +T Cells Regulated by Glycometabolism. Biochem Pharmacol 2022; 204:115197. [PMID: 35926651 DOI: 10.1016/j.bcp.2022.115197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/21/2022] [Accepted: 07/27/2022] [Indexed: 11/02/2022]
Abstract
Memory CD8+T cells participate in the fight against infection and tumorigenesis as well as in autoimmune disease progression because of their efficient and rapid immune response, long-term survival, and continuous differentiation. At each stage of their formation, maintenance, and function, the cell metabolism must be adjusted to match the functional requirements of the specific stage. Notably, enhanced glycolytic metabolism can generate sufficient levels of adenosine triphosphate (ATP) to form memory CD8+T cells, countering the view that glycolysis prevents the formation of memory CD8+T cells. This review focuses on how glycometabolism regulates memory CD8+T cells and highlights the key mechanisms through which the mammalian target of rapamycin (mTOR) signaling pathway affects memory CD8+T cell formation, maintenance, and function by regulating glycometabolism. In addition, different subpopulations of memory CD8+T cells exhibit different metabolic flexibility during their formation, survival, and functional stages, during which the energy metabolism may be critical. These findings which may explain why enhanced glycolytic metabolism can give rise to memory CD8+T cells. Modulating the metabolism of memory CD8+T cells to influence specific cell fates may be useful for disease treatment.
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Affiliation(s)
- Xuepei Cai
- Department of Orthodontics, Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Haokun Li
- Department of Immunology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Manyi Wang
- Department of Orthodontics, Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Edward Chu
- Department of Oncology and Cancer Therapeutics Program, Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Ning Wei
- Department of Oncology and Cancer Therapeutics Program, Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Jiayu Lin
- Department of Orthodontics, Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Yun Hu
- Department of Orthodontics, Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Jingtao Dai
- Department of Orthodontics, Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Aijie Chen
- Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Hua Zheng
- Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Qianbing Zhang
- Cancer Research Institute, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Yuxia Zhong
- Microbiome Medicine Center, Department of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Ruoshui Chang
- Department of Immunology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Sha Wu
- Department of Immunology, School of Basic Medical Sciences, Microbiome Medicine Center, Department of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China; Key Laboratory of Functional Proteomics of Guangdong Province, Guangzhou, China; National Demonstration Center for Experimental Education of Basic Medical Sciences of China, Guangzhou, China.
| | - Yaomu Xiao
- Department of Orthodontics, Stomatological Hospital, Southern Medical University, Guangzhou, China.
| | - Chufeng Liu
- Department of Orthodontics, Stomatological Hospital, Southern Medical University, Guangzhou, China.
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13
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Yue S, Li G, He S, Li T. The central role of mTORC1 in amino acid sensing. Cancer Res 2022; 82:2964-2974. [PMID: 35749594 DOI: 10.1158/0008-5472.can-21-4403] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 04/28/2022] [Accepted: 06/17/2022] [Indexed: 11/16/2022]
Abstract
The mechanistic target of rapamycin (mTOR) is a master regulator of cell growth that controls cell homeostasis in response to nutrients, growth factors, and other environmental cues. Recent studies have emphasized the importance of lysosomes as a hub for nutrient sensing, especially amino acid sensing by mTORC1. This review highlights recent advances in understanding the amino acid-mTORC1 signaling axis and the role of mTORC1 in cancer.
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14
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Abstract
The mechanistic target of the rapamycin (mTOR) signaling pathway is the central regulator of cell growth and proliferation by integrating growth factor and nutrient availability. Under healthy physiological conditions, this process is tightly coordinated and essential to maintain whole-body homeostasis. Not surprisingly, dysregulated mTOR signaling underpins several diseases with increasing incidence worldwide, including obesity, diabetes, and cancer. Consequently, there is significant clinical interest in developing therapeutic strategies that effectively target this pathway. The transition of mTOR inhibitors from the bench to bedside, however, has largely been marked with challenges and shortcomings, such as the development of therapy resistance and adverse side effects in patients. In this review, we discuss the current status of first-, second-, and third-generation mTOR inhibitors as a cancer therapy in both preclinical and clinical settings, with a particular emphasis on the mechanisms of drug resistance. We focus especially on the emerging role of diet as an important environmental determinant of therapy response, and posit a conceptual framework that links nutrient availability and whole-body metabolic states such as obesity with many of the previously defined processes that drive resistance to mTOR-targeted therapies. Given the role of mTOR as a central integrator of cell metabolism and function, we propose that modulating nutrient inputs through dietary interventions may influence the signaling dynamics of this pathway and compensatory nodes. In doing so, new opportunities for exploiting diet/drug synergies are highlighted that may unlock the therapeutic potential of mTOR inhibitors as a cancer treatment.
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Affiliation(s)
- Nikos Koundouros
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021,USA
- Department of Pharmacology, Weill Cornell Medicine, New York, NY 10021, USA
- Correspondence: Nikos Koundouros, Meyer Cancer Center, Weill Cornell Medicine, 413 East 69th Street, New York, NY, 10021 USA.
| | - John Blenis
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021,USA
- Department of Pharmacology, Weill Cornell Medicine, New York, NY 10021, USA
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10021, USA
- Correspondence: John Blenis, Meyer Cancer Center, Weill Cornell Medicine, 413 East 69th Street, New York, NY, 10021 USA.
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15
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mTOR substrate phosphorylation in growth control. Cell 2022; 185:1814-1836. [PMID: 35580586 DOI: 10.1016/j.cell.2022.04.013] [Citation(s) in RCA: 145] [Impact Index Per Article: 72.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/05/2022] [Accepted: 04/07/2022] [Indexed: 12/20/2022]
Abstract
The target of rapamycin (TOR), discovered 30 years ago, is a highly conserved serine/threonine protein kinase that plays a central role in regulating cell growth and metabolism. It is activated by nutrients, growth factors, and cellular energy. TOR forms two structurally and functionally distinct complexes, TORC1 and TORC2. TOR signaling activates cell growth, defined as an increase in biomass, by stimulating anabolic metabolism while inhibiting catabolic processes. With emphasis on mammalian TOR (mTOR), we comprehensively reviewed the literature and identified all reported direct substrates. In the context of recent structural information, we discuss how mTORC1 and mTORC2, despite having a common catalytic subunit, phosphorylate distinct substrates. We conclude that the two complexes recruit different substrates to phosphorylate a common, minimal motif.
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16
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Protrudin regulates FAK activation, endothelial cell migration and angiogenesis. Cell Mol Life Sci 2022; 79:220. [PMID: 35368213 PMCID: PMC8977271 DOI: 10.1007/s00018-022-04251-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 02/23/2022] [Accepted: 03/15/2022] [Indexed: 12/13/2022]
Abstract
During angiogenesis, endothelial cells form protrusive sprouts and migrate towards the angiogenic stimulus. In this study, we investigate the role of the endoplasmic reticulum (ER)-anchored protein, Protrudin, in endothelial cell protrusion, migration and angiogenesis. Our results demonstrate that Protrudin regulates angiogenic tube formation in primary endothelial cells, Human umbilical vein endothelial cells (HUVECs). Analysis of RNA sequencing data and its experimental validation revealed cell migration as a prominent cellular function affected in HUVECs subjected to Protrudin knockdown. Further, our results demonstrate that knockdown of Protrudin inhibits focal adhesion kinase (FAK) activation in HUVECs and human aortic endothelial cells (HAECs). This is associated with a loss of polarized phospho-FAK distribution upon Protrudin knockdown as compared to Protrudin expressing HUVECs. Reduction of Protrudin also results in a perinuclear accumulation of mTOR and a decrease in VEGF-mediated S6K activation. However, further experiments suggest that the observed inhibition of angiogenesis in Protrudin knockdown cells is not affected by mTOR disturbance. Therefore, our findings suggest that defects in FAK activation and its abnormal subcellular distribution upon Protrudin knockdown are associated with a detrimental effect on endothelial cell migration and angiogenesis. Furthermore, mice with global Protrudin deletion demonstrate reduced retinal vascular progression. To conclude, our results provide evidence for a novel key role of Protrudin in endothelial cell migration and angiogenesis.
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17
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Huan J, Grivas P, Birch J, Hansel DE. Emerging Roles for Mammalian Target of Rapamycin (mTOR) Complexes in Bladder Cancer Progression and Therapy. Cancers (Basel) 2022; 14:1555. [PMID: 35326708 PMCID: PMC8946148 DOI: 10.3390/cancers14061555] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/03/2022] [Accepted: 03/15/2022] [Indexed: 12/15/2022] Open
Abstract
The mammalian target of rapamycin (mTOR) pathway regulates important cellular functions. Aberrant activation of this pathway, either through upstream activation by growth factors, loss of inhibitory controls, or molecular alterations, can enhance cancer growth and progression. Bladder cancer shows high levels of mTOR activity in approximately 70% of urothelial carcinomas, suggesting a key role for this pathway in this cancer. mTOR signaling initiates through upstream activation of phosphatidylinositol 3 kinase (PI3K) and protein kinase B (AKT) and results in activation of either mTOR complex 1 (mTORC1) or mTOR complex 2 (mTORC2). While these complexes share several key protein components, unique differences in their complex composition dramatically alter the function and downstream cellular targets of mTOR activity. While significant work has gone into analysis of molecular alterations of the mTOR pathway in bladder cancer, this has not yielded significant benefit in mTOR-targeted therapy approaches in urothelial carcinoma to date. New discoveries regarding signaling convergence onto mTOR complexes in bladder cancer could yield unique insights the biology and targeting of this aggressive disease. In this review, we highlight the functional significance of mTOR signaling in urothelial carcinoma and its potential impact on future therapy implications.
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Affiliation(s)
- Jianya Huan
- Department of Pathology & Laboratory Medicine, Oregon Health & Science University, Portland, OR 97239, USA; (J.H.); (J.B.)
| | - Petros Grivas
- Division of Medical Oncology, Department of Medicine, University of Washington School of Medicine, Fred Hutchinson Cancer Research Center, Seattle Cancer Care Alliance, Seattle, WA 98195, USA;
| | - Jasmine Birch
- Department of Pathology & Laboratory Medicine, Oregon Health & Science University, Portland, OR 97239, USA; (J.H.); (J.B.)
| | - Donna E. Hansel
- Department of Pathology & Laboratory Medicine, Oregon Health & Science University, Portland, OR 97239, USA; (J.H.); (J.B.)
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18
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Barzegar Behrooz A, Talaie Z, Jusheghani F, Łos MJ, Klonisch T, Ghavami S. Wnt and PI3K/Akt/mTOR Survival Pathways as Therapeutic Targets in Glioblastoma. Int J Mol Sci 2022; 23:ijms23031353. [PMID: 35163279 PMCID: PMC8836096 DOI: 10.3390/ijms23031353] [Citation(s) in RCA: 77] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 02/06/2023] Open
Abstract
Glioblastoma (GBM) is a devastating type of brain tumor, and current therapeutic treatments, including surgery, chemotherapy, and radiation, are palliative at best. The design of effective and targeted chemotherapeutic strategies for the treatment of GBM require a thorough analysis of specific signaling pathways to identify those serving as drivers of GBM progression and invasion. The Wnt/β-catenin and PI3K/Akt/mTOR (PAM) signaling pathways are key regulators of important biological functions that include cell proliferation, epithelial–mesenchymal transition (EMT), metabolism, and angiogenesis. Targeting specific regulatory components of the Wnt/β-catenin and PAM pathways has the potential to disrupt critical brain tumor cell functions to achieve critical advancements in alternative GBM treatment strategies to enhance the survival rate of GBM patients. In this review, we emphasize the importance of the Wnt/β-catenin and PAM pathways for GBM invasion into brain tissue and explore their potential as therapeutic targets.
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Affiliation(s)
- Amir Barzegar Behrooz
- Brain Cancer Department, Asu vanda Gene Industrial Research Company, Tehran 1533666398, Iran; (A.B.B.); (Z.T.)
| | - Zahra Talaie
- Brain Cancer Department, Asu vanda Gene Industrial Research Company, Tehran 1533666398, Iran; (A.B.B.); (Z.T.)
| | - Fatemeh Jusheghani
- Department of Biotechnology, Asu vanda Gene Industrial Research Company, Tehran 1533666398, Iran;
| | - Marek J. Łos
- Biotechnology Center, Silesian University of Technology, 44-100 Gliwice, Poland;
| | - Thomas Klonisch
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3E 0V9, Canada;
- Department of Pathology, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3E 0V9, Canada
- Department of Surgery, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3E 0V9, Canada
- Department of Medical Microbiology and Infectious Diseases, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3E 0V9, Canada
- Research Institute of Oncology and Hematology, Cancer Care Manitoba, Winnipeg, MB R3E 0V9, Canada
| | - Saeid Ghavami
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3E 0V9, Canada;
- Research Institute of Oncology and Hematology, Cancer Care Manitoba, Winnipeg, MB R3E 0V9, Canada
- Biology of Breathing Theme, Children Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB R3E 0V9, Canada
- Faculty of Medicine, Katowice School of Technology, 40-555 Katowice, Poland
- Correspondence:
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19
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Huynh H, Levitz R, Huang R, Kahn JS. mTOR kinase is a therapeutic target for respiratory syncytial virus and coronaviruses. Sci Rep 2021; 11:24442. [PMID: 34952911 PMCID: PMC8709853 DOI: 10.1038/s41598-021-03814-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 11/25/2021] [Indexed: 01/02/2023] Open
Abstract
Therapeutic interventions targeting viral infections remain a significant challenge for both the medical and scientific communities. While specific antiviral agents have shown success as therapeutics, viral resistance inevitably develops, making many of these approaches ineffective. This inescapable obstacle warrants alternative approaches, such as the targeting of host cellular factors. Respiratory syncytial virus (RSV), the major respiratory pathogen of infants and children worldwide, causes respiratory tract infection ranging from mild upper respiratory tract symptoms to severe life-threatening lower respiratory tract disease. Despite the fact that the molecular biology of the virus, which was originally discovered in 1956, is well described, there is no vaccine or effective antiviral treatment against RSV infection. Here, we demonstrate that targeting host factors, specifically, mTOR signaling, reduces RSV protein production and generation of infectious progeny virus. Further, we show that this approach can be generalizable as inhibition of mTOR kinases reduces coronavirus gene expression, mRNA transcription and protein production. Overall, defining virus replication-dependent host functions may be an effective means to combat viral infections, particularly in the absence of antiviral drugs.
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Affiliation(s)
- HoangDinh Huynh
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Ruth Levitz
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Rong Huang
- Department of Research Administration Children's Medical Center, Dallas, TX, 75235, USA
| | - Jeffrey S Kahn
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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20
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Sahu D, Huan J, Wang H, Sahoo D, Casteel DE, Klemke RL, Boss GR, Hansel DE. Bladder Cancer Invasion Is Mediated by Mammalian Target of Rapamycin Complex 2-Driven Regulation of Nitric Oxide and Invadopodia Formation. THE AMERICAN JOURNAL OF PATHOLOGY 2021; 191:2203-2218. [PMID: 34428425 DOI: 10.1016/j.ajpath.2021.08.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 07/14/2021] [Accepted: 08/06/2021] [Indexed: 01/05/2023]
Abstract
Bladder cancer invasion depends on mammalian target of rapamycin complex 2 (mTORC2) activity, although the downstream mTORC2 effectors that mediate this effect have not been fully defined. One potential downstream effector is the arginine derivative nitric oxide (NO). We identified a stage-associated increase in the expression of the NO-generating enzymes endothelial NO synthase (NOS) and inducible NOS (iNOS) in human bladder cancer. Reduction of NOS activity by pharmacologic inhibition or silencing of NOS enzymes reduced cancer cell invasion, with similar effects observed using the NO scavenger cobinamide. By contrast, enhanced invasion was seen with the NO donor Deta-NONOate and an analog of the downstream NO second messenger cGMP. We next evaluated NOS expression in invadopodia, which are cellular protrusions that form the invasive tips of cancer cells. Invadopodia were enriched in both iNOS protein and mTORC2 activity, and invadopodia formation was increased by Deta-NONOate and decreased by cobinamide and ablation of mTORC2 activity. mTORC2 additionally increased expression of iNOS. Using a zebrafish model, injection of iNOS- or rictor-silenced cells reduced the frequency of bladder cancer cell metastasis in zebrafish. These results indicate that mTORC2 can mediate bladder cancer cell invasion through increased iNOS expression, resulting in increased NO and cGMP production in invadopodia and further propagation of invadopodia formation.
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Affiliation(s)
- Divya Sahu
- Department of Pathology & Laboratory Medicine, University of California at San Diego, La Jolla, California
| | - Jianya Huan
- Department of Pathology & Laboratory Medicine, Oregon Health & Science University, Portland, Oregon
| | - Huawei Wang
- Department of Pathology & Laboratory Medicine, University of California at San Diego, La Jolla, California
| | - Debashis Sahoo
- Department of Pathology & Laboratory Medicine, University of California at San Diego, La Jolla, California
| | - Darren E Casteel
- Department of Medicine, University of California at San Diego, La Jolla, California
| | - Richard L Klemke
- Department of Pathology & Laboratory Medicine, University of California at San Diego, La Jolla, California
| | - Gerry R Boss
- Department of Medicine, University of California at San Diego, La Jolla, California
| | - Donna E Hansel
- Department of Pathology & Laboratory Medicine, Oregon Health & Science University, Portland, Oregon.
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21
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Current Perspective on the Natural Compounds and Drug Delivery Techniques in Glioblastoma Multiforme. Cancers (Basel) 2021; 13:cancers13112765. [PMID: 34199460 PMCID: PMC8199612 DOI: 10.3390/cancers13112765] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/30/2021] [Accepted: 05/31/2021] [Indexed: 12/20/2022] Open
Abstract
Simple Summary Glioblastoma multiforme (GBM) is one of the belligerent neoplasia that metastasize to other brain regions and invade nearby healthy tissues. However, the treatments available are associated with some limitations, such as high variations in solid tumors and deregulation of multiple cellular pathways. The heterogeneity of the GBM tumor and its aggressive infiltration into the nearby tissues makes it difficult to treat. Hence, the development of multimodality therapy that can be more effective, novel, with fewer side effects, improving the prognosis for GBM is highly desired. This review evaluated the use of natural phytoconstituents as an alternative for the development of a new therapeutic strategy. The key aspects of GBM and the potential of drug delivery techniques were also assessed, for tumor site delivery with limited side-effects. These efforts will help to provide better therapeutic options to combat GBM in future. Abstract Glioblastoma multiforme (GBM) is one of the debilitating brain tumors, being associated with extremely poor prognosis and short median patient survival. GBM is associated with complex pathogenesis with alterations in various cellular signaling events, that participate in cell proliferation and survival. The impairment in cellular redox pathways leads to tumorigenesis. The current standard pharmacological regimen available for glioblastomas, such as radiotherapy and surgical resection following treatment with chemotherapeutic drug temozolomide, remains fatal, due to drug resistance, metastasis and tumor recurrence. Thus, the demand for an effective therapeutic strategy for GBM remains elusive. Hopefully, novel products from natural compounds are suggested as possible solutions. They protect glial cells by reducing oxidative stress and neuroinflammation, inhibiting proliferation, inducing apoptosis, inhibiting pro-oncogene events and intensifying the potent anti-tumor therapies. Targeting aberrant cellular pathways in the amelioration of GBM could promote the development of new therapeutic options that improve patient quality of life and extend survival. Consequently, our review emphasizes several natural compounds in GBM treatment. We also assessed the potential of drug delivery techniques such as nanoparticles, Gliadel wafers and drug delivery using cellular carriers which could lead to a novel path for the obliteration of GBM.
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22
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Chow RY, Levee TM, Kaur G, Cedeno DP, Doan LT, Atwood SX. MTOR promotes basal cell carcinoma growth through atypical PKC. Exp Dermatol 2021; 30:358-366. [PMID: 33617094 PMCID: PMC9924159 DOI: 10.1111/exd.14255] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 10/27/2020] [Accepted: 11/30/2020] [Indexed: 12/14/2022]
Abstract
Advanced basal cell carcinomas (BCCs) are driven by the Hedgehog (HH) pathway and often possess inherent resistance to SMO inhibitors. Identifying and targeting pathways that bypass SMO could provide alternative treatments for patients with advanced or metastatic BCC. Here, we use a combination of RNA-sequencing analysis of advanced human BCC tumor-normal pairs and immunostaining of human and mouse BCC samples to identify an MTOR expression signature in BCC. Pharmacological inhibition of MTOR activity in BCC cells significantly reduces cell proliferation without affecting HH signalling. Similarly, treatment of the Ptch1 fl/fl ; Gli1-CreERT2 mouse BCC tumor model with everolimus reduces tumor growth. aPKC, a downstream target of MTOR, shows reduced activity, suggesting that MTOR promotes tumor growth by activating aPKC and demonstrating that suppressing MTOR could be a promising target for BCC patients.
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Affiliation(s)
- Rachel Y. Chow
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA
| | - Taylor M. Levee
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA
| | - Gurleen Kaur
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA
| | - Daniel P. Cedeno
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA
| | - Linda T. Doan
- Department of Dermatology, University of California, Irvine, CA, USA
| | - Scott X. Atwood
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA,Department of Dermatology, University of California, Irvine, CA, USA,Chao Family Comprehensive Cancer Center, University of California, Irvine, CA, USA
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23
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Akbari Dilmaghani N, Safaroghli-Azar A, Pourbagheri-Sigaroodi A, Bashash D. The PI3K/Akt/mTORC signaling axis in head and neck squamous cell carcinoma: Possibilities for therapeutic interventions either as single agents or in combination with conventional therapies. IUBMB Life 2021; 73:618-642. [PMID: 33476088 DOI: 10.1002/iub.2446] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 12/24/2020] [Indexed: 01/08/2023]
Abstract
The latest advances in the sequencing methods in head and neck squamous cell carcinoma (HNSCC) tissues have revolutionized our understanding of the disease by taking off the veil from the most frequent genetic alterations in the components of the oncogenic pathways. Among all the identified alterations, aberrancies in the genes attributed to the phosphoinositide 3-kinases (PI3K) axis have attracted special attention as they were altered in more than 90% of the tissues isolated from HNSCC patients. In fact, the association between these aberrancies and the increased risk of cancer metastasis suggested this axis as an "Achilles Heel" of HNSCC, which may be therapeutically targeted. The results of the clinical trials investigating the therapeutic potential of the inhibitors targeting the components of the PI3K axis in the treatment of HNSCC patients, either alone or in a combined-modal strategy, opened a new chapter in the treatment strategy of this malignancy. The present study aimed to review the importance of the PI3K axis in the pathogenesis of HNSCC and also provide a piece of information about the breakthroughs and challenges of PI3K inhibitors in the therapeutic strategies of the disease.
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Affiliation(s)
- Nader Akbari Dilmaghani
- Hearing Disorders Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Otolaryngology, Head and Neck Surgery, Loghman Hakim Educational Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ava Safaroghli-Azar
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Atieh Pourbagheri-Sigaroodi
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Davood Bashash
- Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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24
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Velnati S, Centonze S, Girivetto F, Capello D, Biondi RM, Bertoni A, Cantello R, Ragnoli B, Malerba M, Graziani A, Baldanzi G. Identification of Key Phospholipids That Bind and Activate Atypical PKCs. Biomedicines 2021; 9:biomedicines9010045. [PMID: 33419210 PMCID: PMC7825596 DOI: 10.3390/biomedicines9010045] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/30/2020] [Accepted: 01/01/2021] [Indexed: 12/02/2022] Open
Abstract
PKCζ and PKCι/λ form the atypical protein kinase C subgroup, characterised by a lack of regulation by calcium and the neutral lipid diacylglycerol. To better understand the regulation of these kinases, we systematically explored their interactions with various purified phospholipids using the lipid overlay assays, followed by kinase activity assays to evaluate the lipid effects on their enzymatic activity. We observed that both PKCζ and PKCι interact with phosphatidic acid and phosphatidylserine. Conversely, PKCι is unique in binding also to phosphatidylinositol-monophosphates (e.g., phosphatidylinositol 3-phosphate, 4-phosphate, and 5-phosphate). Moreover, we observed that phosphatidylinositol 4-phosphate specifically activates PKCι, while both isoforms are responsive to phosphatidic acid and phosphatidylserine. Overall, our results suggest that atypical Protein kinase C (PKC) localisation and activity are regulated by membrane lipids distinct from those involved in conventional PKCs and unveil a specific regulation of PKCι by phosphatidylinositol-monophosphates.
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Affiliation(s)
- Suresh Velnati
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
- Center for Translational Research on Allergic and Autoimmune Diseases (CAAD), University of Piemonte Orientale, 28100 Novara, Italy
- Correspondence:
| | - Sara Centonze
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
- Center for Translational Research on Allergic and Autoimmune Diseases (CAAD), University of Piemonte Orientale, 28100 Novara, Italy
| | - Federico Girivetto
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
- Center for Translational Research on Allergic and Autoimmune Diseases (CAAD), University of Piemonte Orientale, 28100 Novara, Italy
| | - Daniela Capello
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
- UPO Biobank, University of Piemonte Orientale, 28100 Novara, Italy
| | - Ricardo M. Biondi
- Department of Internal Medicine 1, Goethe University Hospital Frankfurt, 60590 Frankfurt, Germany;
- Biomedicine Research Institute of Buenos Aires—CONICET—Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina
| | - Alessandra Bertoni
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
| | - Roberto Cantello
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
| | | | - Mario Malerba
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
- Respiratory Unit, Sant’Andrea Hospital, 13100 Vercelli, Italy;
| | - Andrea Graziani
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, 10126 Turin, Italy;
- Division of Oncology, Università Vita-Salute San Raffaele, 20132 Milan, Italy
| | - Gianluca Baldanzi
- Department of Translational Medicine, University of Piemonte Orientale, 28100 Novara, Italy; (S.C.); (F.G.); (D.C.); (A.B.); (R.C.); (M.M.); (G.B.)
- Center for Translational Research on Allergic and Autoimmune Diseases (CAAD), University of Piemonte Orientale, 28100 Novara, Italy
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Yang C, Malarkannan S. Transcriptional Regulation of NK Cell Development by mTOR Complexes. Front Cell Dev Biol 2020; 8:566090. [PMID: 33240877 PMCID: PMC7683515 DOI: 10.3389/fcell.2020.566090] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 10/16/2020] [Indexed: 11/13/2022] Open
Abstract
The mechanistic target of Rapamycin (mTOR) is essential for multiple cellular processes. The unique roles of mTOR complex 1 (mTORC1) or mTOR2 in regulating immune functions are emerging. NK cells are the major lymphocyte subset of innate immunity, and their development and effector functions require metabolic reprogramming. Recent studies demonstrate that in NK cells, conditionally disrupting the formation of mTORC1 or mTOR complex 2 (mTORC2) alters their development significantly. Transcriptomic profiling of NK cells at the single-cell level demonstrates that mTORC1 was critical for the early developmental progression, while mTORC2 regulated the terminal maturation. In this review, we summarize the essential roles of mTOR complexes in NK development and functions.
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Affiliation(s)
- Chao Yang
- Laboratory of Molecular Immunology and Immunotherapy, Versiti Blood Research Institute, Milwaukee, WI, United States.,Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Subramaniam Malarkannan
- Laboratory of Molecular Immunology and Immunotherapy, Versiti Blood Research Institute, Milwaukee, WI, United States.,Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, United States
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26
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Ucha M, Roura-Martínez D, Ambrosio E, Higuera-Matas A. The role of the mTOR pathway in models of drug-induced reward and the behavioural constituents of addiction. J Psychopharmacol 2020; 34:1176-1199. [PMID: 32854585 DOI: 10.1177/0269881120944159] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Exposure to drugs of abuse induces neuroadaptations in critical nodes of the so-called reward systems that are thought to mediate the transition from controlled drug use to the compulsive drug-seeking that characterizes addictive disorders. These neural adaptations are likely to require protein synthesis, which is regulated, among others, by the mechanistic target of the rapamycin kinase (mTOR) signalling cascade. METHODS We have performed a narrative review of the literature available in PubMed about the involvement of the mTOR pathway in drug-reward and addiction-related phenomena. AIMS The aim of this study was to review the underlying architecture of this complex intracellular network and to discuss the alterations of its components that are evident after exposure to drugs of abuse. The aim was also to delineate the effects that manipulations of the mTOR network have on models of drug reward and on paradigms that recapitulate some of the psychological components of addiction. RESULTS There is evidence for the involvement of the mTOR pathway in the acute and rewarding effects of drugs of abuse, especially psychostimulants. However, the data regarding opiates are scarce. There is a need to use sophisticated animal models of addiction to ascertain the real role of the mTOR pathway in this pathology and not just in drug-mediated reward. The involvement of this pathway in behavioural addictions and impulsivity should also be studied in detail in the future. CONCLUSIONS Although there is a plethora of data about the modulation of mTOR by drugs of abuse, the involvement of this signalling pathway in addictive disorders requires further research.
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Affiliation(s)
- Marcos Ucha
- Department of Psychobiology, National University for Distance Learning (UNED), Madrid, Spain
| | - David Roura-Martínez
- Department of Psychobiology, National University for Distance Learning (UNED), Madrid, Spain
| | - Emilio Ambrosio
- Department of Psychobiology, National University for Distance Learning (UNED), Madrid, Spain
| | - Alejandro Higuera-Matas
- Department of Psychobiology, National University for Distance Learning (UNED), Madrid, Spain
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27
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Song X, Hu Y, Li Y, Shao R, Liu F, Liu Y. Overview of current targeted therapy in gallbladder cancer. Signal Transduct Target Ther 2020; 5:230. [PMID: 33028805 PMCID: PMC7542154 DOI: 10.1038/s41392-020-00324-2] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 08/08/2020] [Accepted: 09/10/2020] [Indexed: 02/08/2023] Open
Abstract
Gallbladder cancer (GBC) is rare, but is the most malignant type of biliary tract tumor. Unfortunately, only a small population of cancer patients is acceptable for the surgical resection, the current effective regimen; thus, the high mortality rate has been static for decades. To substantially circumvent the stagnant scenario, a number of therapeutic approaches owing to the creation of advanced technologic measures (e.g., next-generation sequencing, transcriptomics, proteomics) have been intensively innovated, which include targeted therapy, immunotherapy, and nanoparticle-based delivery systems. In the current review, we primarily focus on the targeted therapy capable of specifically inhibiting individual key molecules that govern aberrant signaling cascades in GBC. Global clinical trials of targeted therapy in GBC are updated and may offer great value for novel pathologic and therapeutic insights of this deadly disease, ultimately improving the efficacy of treatment.
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Affiliation(s)
- Xiaoling Song
- Department of General Surgery and Laboratory of General Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 1665 Kongjiang Road, 200092, Shanghai, China
- Shanghai Key Laboratory of Biliary Tract Disease Research, 1665 Kongjiang Road, 200092, Shanghai, China
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, School of Medicine, Shanghai Jiao Tong University, 200127, Shanghai, China
| | - Yunping Hu
- Department of General Surgery and Laboratory of General Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 1665 Kongjiang Road, 200092, Shanghai, China
- Shanghai Key Laboratory of Biliary Tract Disease Research, 1665 Kongjiang Road, 200092, Shanghai, China
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, School of Medicine, Shanghai Jiao Tong University, 200127, Shanghai, China
| | - Yongsheng Li
- Shanghai Key Laboratory of Biliary Tract Disease Research, 1665 Kongjiang Road, 200092, Shanghai, China
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, School of Medicine, Shanghai Jiao Tong University, 200127, Shanghai, China
- Department of Biliary-Pancreatic Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 200127, Shanghai, China
| | - Rong Shao
- Shanghai Key Laboratory of Biliary Tract Disease Research, 1665 Kongjiang Road, 200092, Shanghai, China.
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, School of Medicine, Shanghai Jiao Tong University, 200127, Shanghai, China.
- Department of Pharmacology, Shanghai Jiao Tong University School of Medicine, 200025, Shanghai, China.
| | - Fatao Liu
- Department of General Surgery and Laboratory of General Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 1665 Kongjiang Road, 200092, Shanghai, China.
- Shanghai Key Laboratory of Biliary Tract Disease Research, 1665 Kongjiang Road, 200092, Shanghai, China.
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, School of Medicine, Shanghai Jiao Tong University, 200127, Shanghai, China.
| | - Yingbin Liu
- Shanghai Key Laboratory of Biliary Tract Disease Research, 1665 Kongjiang Road, 200092, Shanghai, China.
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, School of Medicine, Shanghai Jiao Tong University, 200127, Shanghai, China.
- Department of Biliary-Pancreatic Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 200127, Shanghai, China.
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28
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Chen Y, Zhou X. Research progress of mTOR inhibitors. Eur J Med Chem 2020; 208:112820. [PMID: 32966896 DOI: 10.1016/j.ejmech.2020.112820] [Citation(s) in RCA: 110] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/16/2020] [Accepted: 09/03/2020] [Indexed: 12/25/2022]
Abstract
Mammalian target of rapamycin (mTOR) is a highly conserved Serine/Threonine (Ser/Thr) protein kinase, which belongs to phosphatidylinositol-3-kinase-related kinase (PIKK) protein family. mTOR exists as two types of protein complex: mTORC1 and mTORC2, which act as central controller regulating processes of cell metabolism, growth, proliferation, survival and autophagy. The mTOR inhibitors block mTOR signaling pathway, producing anti-inflammatory, anti-proliferative, autophagy and apoptosis induction effects, thus mTOR inhibitors are mainly used in cancer therapy. At present, mTOR inhibitors are divided into four categories: Antibiotic allosteric mTOR inhibitors (first generation), ATP-competitive mTOR inhibitors (second generation), mTOR/PI3K dual inhibitors (second generation) and other new mTOR inhibitors (third generation). In this article, these four categories of mTOR inhibitors and their structures, properties and some clinical researches will be introduced. Among them, we focus on the structure of mTOR inhibitors and try to analyze the structure-activity relationship. mTOR inhibitors are classified according to their chemical structure and their contents are introduced systematically. Moreover, some natural products that have direct or indirect mTOR inhibitory activities are introduced together. In this article, we analyzed the target, binding mode and structure-activity relationship of each generation of mTOR inhibitors and proposed two hypothetic scaffolds (the inverted-Y-shape scaffold and the C-shape scaffold) for the second generation of mTOR inhibitors. These findings may provide some help or reference for drug designing, drug modification or the future development of mTOR inhibitor.
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Affiliation(s)
- Yifan Chen
- School of Pharmaceutical Sciences, Jilin University, Changchun, 130021, China
| | - Xiaoping Zhou
- School of Pharmaceutical Sciences, Jilin University, Changchun, 130021, China.
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Fu W, Hall MN. Regulation of mTORC2 Signaling. Genes (Basel) 2020; 11:E1045. [PMID: 32899613 PMCID: PMC7564249 DOI: 10.3390/genes11091045] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 08/31/2020] [Accepted: 09/02/2020] [Indexed: 12/12/2022] Open
Abstract
Mammalian target of rapamycin (mTOR), a serine/threonine protein kinase and a master regulator of cell growth and metabolism, forms two structurally and functionally distinct complexes, mTOR complex 1 (mTORC1) and mTORC2. While mTORC1 signaling is well characterized, mTORC2 is relatively poorly understood. mTORC2 appears to exist in functionally distinct pools, but few mTORC2 effectors/substrates have been identified. Here, we review recent advances in our understanding of mTORC2 signaling, with particular emphasis on factors that control mTORC2 activity.
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Affiliation(s)
- Wenxiang Fu
- Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming 650500, China
- Biozentrum, University of Basel, CH4056 Basel, Switzerland;
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30
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Melick CH, Jewell JL. Regulation of mTORC1 by Upstream Stimuli. Genes (Basel) 2020; 11:genes11090989. [PMID: 32854217 PMCID: PMC7565831 DOI: 10.3390/genes11090989] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/22/2020] [Accepted: 08/23/2020] [Indexed: 01/08/2023] Open
Abstract
The mammalian target of rapamycin (mTOR) is an evolutionary conserved Ser/Thr protein kinase that senses multiple upstream stimuli to control cell growth, metabolism, and autophagy. mTOR is the catalytic subunit of mTOR complex 1 (mTORC1). A significant amount of research has uncovered the signaling pathways regulated by mTORC1, and the involvement of these signaling cascades in human diseases like cancer, diabetes, and ageing. Here, we review advances in mTORC1 regulation by upstream stimuli. We specifically focus on how growth factors, amino acids, G-protein coupled receptors (GPCRs), phosphorylation, and small GTPases regulate mTORC1 activity and signaling.
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Affiliation(s)
- Chase H. Melick
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA;
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jenna L. Jewell
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA;
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Correspondence:
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31
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Chou PC, Rajput S, Zhao X, Patel C, Albaciete D, Oh WJ, Daguplo HQ, Patel N, Su B, Werlen G, Jacinto E. mTORC2 Is Involved in the Induction of RSK Phosphorylation by Serum or Nutrient Starvation. Cells 2020; 9:E1567. [PMID: 32605013 PMCID: PMC7408474 DOI: 10.3390/cells9071567] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 06/17/2020] [Accepted: 06/23/2020] [Indexed: 12/26/2022] Open
Abstract
Cells adjust to nutrient fluctuations to restore metabolic homeostasis. The mechanistic target of rapamycin (mTOR) complex 2 responds to nutrient levels and growth signals to phosphorylate protein kinases belonging to the AGC (Protein Kinases A,G,C) family such as Akt and PKC. Phosphorylation of these AGC kinases at their conserved hydrophobic motif (HM) site by mTORC2 enhances their activation and mediates the functions of mTORC2 in cell growth and metabolism. Another AGC kinase family member that is known to undergo increased phosphorylation at the homologous HM site (Ser380) is the p90 ribosomal S6 kinase (RSK). Phosphorylation at Ser380 is facilitated by the activation of the mitogen-activated protein kinase/extracellular signal regulated kinase (MAPK/ERK) in response to growth factor stimulation. Here, we demonstrate that optimal phosphorylation of RSK at this site requires an intact mTORC2. We also found that RSK is robustly phosphorylated at Ser380 upon nutrient withdrawal or inhibition of glycolysis, conditions that increase mTORC2 activation. However, pharmacological inhibition of mTOR did not abolish RSK phosphorylation at Ser380, indicating that mTOR catalytic activity is not required for this phosphorylation. Since RSK and SIN1β colocalize at the membrane during serum restimulation and acute glutamine withdrawal, mTORC2 could act as a scaffold to enhance RSK HM site phosphorylation. Among the known RSK substrates, the CCTβ subunit of the chaperonin containing TCP-1 (CCT) complex had defective phosphorylation in the absence of mTORC2. Our findings indicate that the mTORC2-mediated phosphorylation of the RSK HM site could confer RSK substrate specificity and reveal that RSK responds to nutrient fluctuations.
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Affiliation(s)
- Po-Chien Chou
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Swati Rajput
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Xiaoyun Zhao
- Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China; (X.Z.); (B.S.)
| | - Chadni Patel
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Danielle Albaciete
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Won Jun Oh
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Heineken Queen Daguplo
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Nikhil Patel
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Bing Su
- Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China; (X.Z.); (B.S.)
| | - Guy Werlen
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Estela Jacinto
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
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32
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Koundouros N, Karali E, Tripp A, Valle A, Inglese P, Perry NJS, Magee DJ, Anjomani Virmouni S, Elder GA, Tyson AL, Dória ML, van Weverwijk A, Soares RF, Isacke CM, Nicholson JK, Glen RC, Takats Z, Poulogiannis G. Metabolic Fingerprinting Links Oncogenic PIK3CA with Enhanced Arachidonic Acid-Derived Eicosanoids. Cell 2020; 181:1596-1611.e27. [PMID: 32559461 PMCID: PMC7339148 DOI: 10.1016/j.cell.2020.05.053] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 03/07/2020] [Accepted: 05/28/2020] [Indexed: 01/02/2023]
Abstract
Oncogenic transformation is associated with profound changes in cellular metabolism, but whether tracking these can improve disease stratification or influence therapy decision-making is largely unknown. Using the iKnife to sample the aerosol of cauterized specimens, we demonstrate a new mode of real-time diagnosis, coupling metabolic phenotype to mutant PIK3CA genotype. Oncogenic PIK3CA results in an increase in arachidonic acid and a concomitant overproduction of eicosanoids, acting to promote cell proliferation beyond a cell-autonomous manner. Mechanistically, mutant PIK3CA drives a multimodal signaling network involving mTORC2-PKCζ-mediated activation of the calcium-dependent phospholipase A2 (cPLA2). Notably, inhibiting cPLA2 synergizes with fatty acid-free diet to restore immunogenicity and selectively reduce mutant PIK3CA-induced tumorigenicity. Besides highlighting the potential for metabolic phenotyping in stratified medicine, this study reveals an important role for activated PI3K signaling in regulating arachidonic acid metabolism, uncovering a targetable metabolic vulnerability that largely depends on dietary fat restriction. VIDEO ABSTRACT.
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Affiliation(s)
- Nikos Koundouros
- Signalling and Cancer Metabolism Team, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK; Division of Systems Medicine, Department of Metabolism Digestion and Reproduction, Imperial College London, London SW7 2AZ, UK
| | - Evdoxia Karali
- Signalling and Cancer Metabolism Team, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - Aurelien Tripp
- Signalling and Cancer Metabolism Team, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - Adamo Valle
- Signalling and Cancer Metabolism Team, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK; Energy Metabolism and Nutrition, Research Institute of Health Sciences (IUNICS), University of Balearic Islands, 07122 Palma de Mallorca, Spain; Health Research Institute of the Balearic Islands (IdISBa), University of Balearic Islands, 07120 Palma de Mallorca, Spain; Biomedical Research Networking Center for Physiopathology of Obesity and Nutrition (CIBERobn CB06/03/0043), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Paolo Inglese
- Division of Systems Medicine, Department of Metabolism Digestion and Reproduction, Imperial College London, London SW7 2AZ, UK
| | - Nicholas J S Perry
- Signalling and Cancer Metabolism Team, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - David J Magee
- Signalling and Cancer Metabolism Team, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK; Pain Medicine Department, The Royal Marsden Hospital, London, UK
| | - Sara Anjomani Virmouni
- Signalling and Cancer Metabolism Team, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK; Department of Life Sciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK
| | - George A Elder
- Signalling and Cancer Metabolism Team, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK; School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Adam L Tyson
- Flow Cytometry and Light Microscopy Core Facility, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK; Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London, 25 Howland Street, London W1T 4JG, UK
| | - Maria Luisa Dória
- Division of Systems Medicine, Department of Metabolism Digestion and Reproduction, Imperial College London, London SW7 2AZ, UK
| | - Antoinette van Weverwijk
- Breast Cancer Now Research Centre, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK; Division of Tumor Biology and Immunology, the Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Renata F Soares
- Division of Systems Medicine, Department of Metabolism Digestion and Reproduction, Imperial College London, London SW7 2AZ, UK
| | - Clare M Isacke
- Breast Cancer Now Research Centre, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - Jeremy K Nicholson
- Division of Systems Medicine, Department of Metabolism Digestion and Reproduction, Imperial College London, London SW7 2AZ, UK; The Australian National Phenome Centre, Health Futures Institute, Murdoch University, Perth WA6150, WA, Australia
| | - Robert C Glen
- Division of Systems Medicine, Department of Metabolism Digestion and Reproduction, Imperial College London, London SW7 2AZ, UK; Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Zoltan Takats
- Division of Systems Medicine, Department of Metabolism Digestion and Reproduction, Imperial College London, London SW7 2AZ, UK.
| | - George Poulogiannis
- Signalling and Cancer Metabolism Team, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK; Division of Systems Medicine, Department of Metabolism Digestion and Reproduction, Imperial College London, London SW7 2AZ, UK.
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Small molecule H89 renders the phosphorylation of S6K1 and AKT resistant to mTOR inhibitors. Biochem J 2020; 477:1847-1863. [PMID: 32347294 PMCID: PMC7261416 DOI: 10.1042/bcj20190958] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/27/2020] [Accepted: 04/28/2020] [Indexed: 11/30/2022]
Abstract
The mammalian target of rapamycin (mTOR) is an evolutionarily conserved Ser/Thr kinase that comprises two complexes, termed mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). mTORC1 phosphorylates S6K1 at Thr 389, whereas mTORC2 phosphorylates AKT at Ser 473 to promote cell growth. As the mTOR name implies it is the target of natural product called rapamycin, a clinically approved drug used to treat human disease. Short-term rapamycin treatment inhibits the kinase activity of mTORC1 but not mTORC2. However, the ATP-competitive catalytic mTOR inhibitor Torin1 was identified to inhibit the kinase activity of both mTORC1 and mTORC2. Here, we report that H89 (N-(2-(4-bromocinnamylamino) ethyl)-5-isoquinolinesulfonamide), a well-characterized ATP-mimetic kinase inhibitor, renders the phosphorylation of S6K1 and AKT resistant to mTOR inhibitors across multiple cell lines. Moreover, H89 prevented the dephosphorylation of AKT and S6K1 under nutrient depleted conditions. PKA and other known H89-targeted kinases do not alter the phosphorylation status of S6K1 and AKT. Pharmacological inhibition of some phosphatases also enhanced S6K1 and AKT phosphorylation. These findings suggest a new target for H89 by which it sustains the phosphorylation status of S6K1 and AKT, resulting in mTOR signaling.
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Huang H, Long L, Zhou P, Chapman NM, Chi H. mTOR signaling at the crossroads of environmental signals and T-cell fate decisions. Immunol Rev 2020; 295:15-38. [PMID: 32212344 PMCID: PMC8101438 DOI: 10.1111/imr.12845] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 02/19/2020] [Indexed: 12/28/2022]
Abstract
The evolutionarily conserved serine/threonine kinase mTOR (mechanistic target of rapamycin) forms the distinct protein complexes mTORC1 and mTORC2 and integrates signals from the environment to coordinate downstream signaling events and various cellular processes. T cells rely on mTOR activity for their development and to establish their homeostasis and functional fitness. Here, we review recent progress in our understanding of the upstream signaling and downstream targets of mTOR. We also provide an updated overview of the roles of mTOR in T-cell development, homeostasis, activation, and effector-cell fate decisions, as well as its important impacts on the suppressive activity of regulatory T cells. Moreover, we summarize the emerging roles of mTOR in T-cell exhaustion and transdifferentiation. A better understanding of the contribution of mTOR to T-cell fate decisions will ultimately aid in the therapeutic targeting of mTOR in human disease.
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Affiliation(s)
- Hongling Huang
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Lingyun Long
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
- Equal contribution
| | - Peipei Zhou
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
- Equal contribution
| | - Nicole M. Chapman
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Hongbo Chi
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
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Liu GY, Sabatini DM. mTOR at the nexus of nutrition, growth, ageing and disease. Nat Rev Mol Cell Biol 2020; 21:183-203. [PMID: 31937935 PMCID: PMC7102936 DOI: 10.1038/s41580-019-0199-y] [Citation(s) in RCA: 1386] [Impact Index Per Article: 346.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/26/2019] [Indexed: 12/21/2022]
Abstract
The mTOR pathway integrates a diverse set of environmental cues, such as growth factor signals and nutritional status, to direct eukaryotic cell growth. Over the past two and a half decades, mapping of the mTOR signalling landscape has revealed that mTOR controls biomass accumulation and metabolism by modulating key cellular processes, including protein synthesis and autophagy. Given the pathway's central role in maintaining cellular and physiological homeostasis, dysregulation of mTOR signalling has been implicated in metabolic disorders, neurodegeneration, cancer and ageing. In this Review, we highlight recent advances in our understanding of the complex regulation of the mTOR pathway and discuss its function in the context of physiology, human disease and pharmacological intervention.
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Affiliation(s)
- Grace Y Liu
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
- Broad Institute, Cambridge, MA, USA
- The David H. Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.
- Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Broad Institute, Cambridge, MA, USA.
- The David H. Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA.
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36
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Yang T, Yang WX. The dynamics and regulation of microfilament during spermatogenesis. Gene 2020; 744:144635. [PMID: 32244053 DOI: 10.1016/j.gene.2020.144635] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 02/28/2020] [Accepted: 03/30/2020] [Indexed: 12/22/2022]
Abstract
Spermatogenesis is a highly complex physiological process which contains spermatogonia proliferation, spermatocyte meiosis and spermatid morphogenesis. In the past decade, actin binding proteins and signaling pathways which are critical for regulating the actin cytoskeleton in testis had been found. In this review, we summarized 5 actin-binding proteins that have been proven to play important roles in the seminiferous epithelium. Lack of them perturbs spermatids polarity and the transport of spermatids. The loss of Arp2/3 complex, Formin1, Eps8, Palladin and Plastin3 cause sperm release failure suggesting their irreplaceable role in spermatogenesis. Actin regulation relies on multiple signal pathways. The PI3K/Akt signaling pathway positively regulate the mTOR pathway to promote actin reorganization in seminiferous epithelium. Conversely, TSC1/TSC2 complex, the upstream of mTOR, is activated by the LKB1/AMPK pathway to inhibit cell proliferation, differentiation and migration. The increasing researches focus on the function of actin binding proteins (ABPs), however, their collaborative regulation of actin patterns and potential regulatory signaling networks remains unclear. We reviewed ABPs that play important roles in mammalian spermatogenesis and signal pathways involved in the regulation of microfilaments. We suggest that more relevant studies should be performed in the future.
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Affiliation(s)
- Tong Yang
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Wan-Xi Yang
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
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37
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Zhao D, Jiang M, Zhang X, Hou H. The role of RICTOR amplification in targeted therapy and drug resistance. Mol Med 2020; 26:20. [PMID: 32041519 PMCID: PMC7011243 DOI: 10.1186/s10020-020-0146-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 01/30/2020] [Indexed: 12/11/2022] Open
Abstract
The emergence of tyrosine kinase inhibitors (TKIs) has changed the current treatment paradigm and achieved good results in recent decades. However, an increasing number of studies have indicated that the complex network of receptor tyrosine kinase (RTK) co-activation could influence the characteristic phenotypes of cancer and the tumor response to targeted treatments. One of strategies to blocking RTK co-activation is targeting the downstream factors of RTK, such as PI3K-AKT-mTOR pathway. RICTOR, a core component of mTORC2, acts as a key effector molecule of the PI3K-AKT pathway; its amplification is often associated with poor clinical outcomes and resistance to TKIs. Here, we discuss the biology of RICTOR in tumor and the prospects of targeting RICTOR as a complementary therapy to inhibit RTK co-activation.
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Affiliation(s)
- Deze Zhao
- Department of Medical Oncology, The Affiliated Hospital of Qingdao University, Qingdao University, 16 Jiangsu Road, Qingdao, 266005, China
| | - Man Jiang
- Department of Medical Oncology, The Affiliated Hospital of Qingdao University, Qingdao University, 16 Jiangsu Road, Qingdao, 266005, China
| | - Xiaochun Zhang
- Department of Medical Oncology, The Affiliated Hospital of Qingdao University, Qingdao University, 16 Jiangsu Road, Qingdao, 266005, China
| | - Helei Hou
- Department of Medical Oncology, The Affiliated Hospital of Qingdao University, Qingdao University, 16 Jiangsu Road, Qingdao, 266005, China.
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38
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Knudsen JR, Fritzen AM, James DE, Jensen TE, Kleinert M, Richter EA. Growth Factor-Dependent and -Independent Activation of mTORC2. Trends Endocrinol Metab 2020; 31:13-24. [PMID: 31699566 DOI: 10.1016/j.tem.2019.09.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 08/19/2019] [Accepted: 09/12/2019] [Indexed: 01/03/2023]
Abstract
The target of rapamycin complex 2 (TORC2) was discovered in 2002 in budding yeast. Its mammalian counterpart, mTORC2, was first described in 2004. Soon thereafter it was demonstrated that mTORC2 directly phosphorylates Akt on Ser473, ending a long search for the elusive 'second' insulin-responsive Akt kinase. In this review we discuss key evidence pertaining to the subcellular localization of mTORC2, highlighting a spatial heterogeneity that relates to mTORC2 activation. We summarize current models for how growth factors (GFs), such as insulin, trigger mTORC2 activation, and we provide a comprehensive discussion focusing on a new exciting frontier, the molecular mechanisms underpinning GF-independent activation of mTORC2.
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Affiliation(s)
- Jonas R Knudsen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Andreas M Fritzen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - David E James
- School of Life and Environmental Sciences and Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia; Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Thomas E Jensen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Maximilian Kleinert
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark; Institute for Diabetes and Obesity, Helmholtz Diabetes Center (HDC), Helmholtz Zentrum Muenchen & German Center for Diabetes Research (DZD), Neuherberg, Germany.
| | - Erik A Richter
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.
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39
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Koundouros N, Poulogiannis G. Reprogramming of fatty acid metabolism in cancer. Br J Cancer 2020; 122:4-22. [PMID: 31819192 PMCID: PMC6964678 DOI: 10.1038/s41416-019-0650-z] [Citation(s) in RCA: 777] [Impact Index Per Article: 194.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/21/2019] [Accepted: 11/01/2019] [Indexed: 02/08/2023] Open
Abstract
A common feature of cancer cells is their ability to rewire their metabolism to sustain the production of ATP and macromolecules needed for cell growth, division and survival. In particular, the importance of altered fatty acid metabolism in cancer has received renewed interest as, aside their principal role as structural components of the membrane matrix, they are important secondary messengers, and can also serve as fuel sources for energy production. In this review, we will examine the mechanisms through which cancer cells rewire their fatty acid metabolism with a focus on four main areas of research. (1) The role of de novo synthesis and exogenous uptake in the cellular pool of fatty acids. (2) The mechanisms through which molecular heterogeneity and oncogenic signal transduction pathways, such as PI3K-AKT-mTOR signalling, regulate fatty acid metabolism. (3) The role of fatty acids as essential mediators of cancer progression and metastasis, through remodelling of the tumour microenvironment. (4) Therapeutic strategies and considerations for successfully targeting fatty acid metabolism in cancer. Further research focusing on the complex interplay between oncogenic signalling and dysregulated fatty acid metabolism holds great promise to uncover novel metabolic vulnerabilities and improve the efficacy of targeted therapies.
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Affiliation(s)
- Nikos Koundouros
- Signalling and Cancer Metabolism Team, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
| | - George Poulogiannis
- Signalling and Cancer Metabolism Team, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK.
- Division of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, London, SW7 2AZ, UK.
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40
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Wang H, Liu Y, Wang D, Xu Y, Dong R, Yang Y, Lv Q, Chen X, Zhang Z. The Upstream Pathway of mTOR-Mediated Autophagy in Liver Diseases. Cells 2019; 8:E1597. [PMID: 31835352 PMCID: PMC6953127 DOI: 10.3390/cells8121597] [Citation(s) in RCA: 161] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/29/2019] [Accepted: 12/03/2019] [Indexed: 12/11/2022] Open
Abstract
Autophagy, originally found in liver experiments, is a cellular process that degrades damaged organelle or protein aggregation. This process frees cells from various stress states is a cell survival mechanism under stress stimulation. It is now known that dysregulation of autophagy can cause many liver diseases. Therefore, how to properly regulate autophagy is the key to the treatment of liver injury. mechanistic target of rapamycin (mTOR)is the core hub regulating autophagy, which is subject to different upstream signaling pathways to regulate autophagy. This review summarizes three upstream pathways of mTOR: the phosphoinositide 3-kinase (PI3K)/protein kinase (AKT) signaling pathway, the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway, and the rat sarcoma (Ras)/rapidly accelerated fibrosarcoma (Raf)/mitogen-extracellular activated protein kinase kinase (MEK)/ extracellular-signal-regulated kinase (ERK) signaling pathway, specifically explored their role in liver fibrosis, hepatitis B, non-alcoholic fatty liver, liver cancer, hepatic ischemia reperfusion and other liver diseases through the regulation of mTOR-mediated autophagy. Moreover, we also analyzed the crosstalk between these three pathways, aiming to find new targets for the treatment of human liver disease based on autophagy.
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Affiliation(s)
- Haojie Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
| | - Yumei Liu
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
| | - Dongmei Wang
- College of Medical, Henan University of Science and Technology, Luoyang 471000, China;
| | - Yaolu Xu
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
| | - Ruiqi Dong
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
| | - Yuxiang Yang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
| | - Qiongxia Lv
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
| | - Xiaoguang Chen
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
| | - Ziqiang Zhang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
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41
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mTOR signaling in Brown and Beige adipocytes: implications for thermogenesis and obesity. Nutr Metab (Lond) 2019; 16:74. [PMID: 31708995 PMCID: PMC6836431 DOI: 10.1186/s12986-019-0404-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 10/22/2019] [Indexed: 12/18/2022] Open
Abstract
Brown and beige adipocytes are mainly responsible for nonshivering thermogenesis or heat production, despite the fact that they have distinguished features in distribution, developmental origin, and functional activation. As a nutrient sensor and critical regulator of energy metabolism, mechanistic target of rapamycin (mTOR) also plays an important role in the development and functional maintenance of adipocytes. While the recent studies support the notion that mTOR (mTORC1 and mTORC2) related signaling pathways are of great significance for thermogenesis and the development of brown and beige adipocytes, the exact roles of mTOR in heat production are controversial. The similarities and disparities in terms of thermogenesis might be ascribed to the use of different animal models and experimental systems, distinct features of brown and beige adipocytes, and the complexity of regulatory networks of mTORC1 and mTORC2 in energy metabolism.
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42
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Wei X, Luo L, Chen J. Roles of mTOR Signaling in Tissue Regeneration. Cells 2019; 8:cells8091075. [PMID: 31547370 PMCID: PMC6769890 DOI: 10.3390/cells8091075] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/06/2019] [Accepted: 09/07/2019] [Indexed: 12/11/2022] Open
Abstract
The mammalian target of rapamycin (mTOR), is a serine/threonine protein kinase and belongs to the phosphatidylinositol 3-kinase (PI3K)-related kinase (PIKK) family. mTOR interacts with other subunits to form two distinct complexes, mTORC1 and mTORC2. mTORC1 coordinates cell growth and metabolism in response to environmental input, including growth factors, amino acid, energy and stress. mTORC2 mainly controls cell survival and migration through phosphorylating glucocorticoid-regulated kinase (SGK), protein kinase B (Akt), and protein kinase C (PKC) kinase families. The dysregulation of mTOR is involved in human diseases including cancer, cardiovascular diseases, neurodegenerative diseases, and epilepsy. Tissue damage caused by trauma, diseases or aging disrupt the tissue functions. Tissue regeneration after injuries is of significance for recovering the tissue homeostasis and functions. Mammals have very limited regenerative capacity in multiple tissues and organs, such as the heart and central nervous system (CNS). Thereby, understanding the mechanisms underlying tissue regeneration is crucial for tissue repair and regenerative medicine. mTOR is activated in multiple tissue injuries. In this review, we summarize the roles of mTOR signaling in tissue regeneration such as neurons, muscles, the liver and the intestine.
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Affiliation(s)
- Xiangyong Wei
- Laboratory of Molecular Developmental Biology, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China.
| | - Lingfei Luo
- Laboratory of Molecular Developmental Biology, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China.
| | - Jinzi Chen
- Laboratory of Molecular Developmental Biology, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China.
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43
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Chia LY, Evans BA, Mukaida S, Bengtsson T, Hutchinson DS, Sato M. Adrenoceptor regulation of the mechanistic target of rapamycin in muscle and adipose tissue. Br J Pharmacol 2019; 176:2433-2448. [PMID: 30740664 PMCID: PMC6592864 DOI: 10.1111/bph.14616] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/08/2019] [Accepted: 01/21/2019] [Indexed: 12/16/2022] Open
Abstract
A vital role of adrenoceptors in metabolism and energy balance has been well documented in the heart, skeletal muscle, and adipose tissue. It has been only recently demonstrated, however, that activation of the mechanistic target of rapamycin (mTOR) makes a significant contribution to various metabolic and physiological responses to adrenoceptor agonists. mTOR exists as two distinct complexes named mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2) and has been shown to play a critical role in protein synthesis, cell proliferation, hypertrophy, mitochondrial function, and glucose uptake. This review will describe the physiological significance of mTORC1 and 2 as a novel paradigm of adrenoceptor signalling in the heart, skeletal muscle, and adipose tissue. Understanding the detailed signalling cascades of adrenoceptors and how they regulate physiological responses is important for identifying new therapeutic targets and identifying novel therapeutic interventions. LINKED ARTICLES: This article is part of a themed section on Adrenoceptors-New Roles for Old Players. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.14/issuetoc.
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Affiliation(s)
- Ling Yeong Chia
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Bronwyn A. Evans
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Saori Mukaida
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Tore Bengtsson
- Department of Molecular Biosciences, The Wenner‐Gren InstituteStockholm UniversityStockholmSweden
| | - Dana S. Hutchinson
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Masaaki Sato
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
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44
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Magre I, Fandade V, Damle I, Banerjee P, Yadav SK, Sonawane M, Joseph J. Nup358 regulates microridge length by controlling SUMOylation-dependent activity of aPKC in zebrafish epidermis. J Cell Sci 2019; 132:jcs.224501. [PMID: 31164446 DOI: 10.1242/jcs.224501] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 05/20/2019] [Indexed: 01/05/2023] Open
Abstract
The Par polarity complex, consisting of Par3, Par6 and atypical protein kinase C (aPKC), plays a crucial role in the establishment and maintenance of cell polarity. Although activation of aPKC is critical for polarity, how this is achieved is unclear. The developing zebrafish epidermis, along with its apical actin-based projections, called microridges, offers a genetically tractable system for unraveling the mechanisms of the cell polarity control. The zebrafish aPKC regulates elongation of microridges by controlling levels of apical Lgl, which acts as a pro-elongation factor. Here, we show that the nucleoporin Nup358 (also known as RanBP2) - a component of the nuclear pore complex and a part of cytoplasmic annulate lamellae (AL) - SUMOylates zebrafish aPKC. Nup358-mediated SUMOylation controls aPKC activity to regulate Lgl-dependent microridge elongation. Our data further suggest that cytoplasmic AL structures are the possible site for Nup358-mediated aPKC SUMOylation. We have unraveled a hitherto unappreciated contribution of Nup358-mediated aPKC SUMOylation in cell polarity regulation.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Indrasen Magre
- National Center for Cell Science, S.P. Pune University Campus, Pune 411 007, India
| | - Vikas Fandade
- National Center for Cell Science, S.P. Pune University Campus, Pune 411 007, India
| | - Indraneel Damle
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India
| | - Poulomi Banerjee
- National Center for Cell Science, S.P. Pune University Campus, Pune 411 007, India
| | - Santosh Kumar Yadav
- National Center for Cell Science, S.P. Pune University Campus, Pune 411 007, India
| | - Mahendra Sonawane
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India
| | - Jomon Joseph
- National Center for Cell Science, S.P. Pune University Campus, Pune 411 007, India
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45
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Mattson AM, Begun DL, Molstad DHH, Meyer MA, Oursler MJ, Westendorf JJ, Bradley EW. Deficiency in the phosphatase PHLPP1 suppresses osteoclast-mediated bone resorption and enhances bone formation in mice. J Biol Chem 2019; 294:11772-11784. [PMID: 31189651 DOI: 10.1074/jbc.ra119.007660] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 05/24/2019] [Indexed: 12/21/2022] Open
Abstract
Enhanced osteoclast-mediated bone resorption and diminished formation may promote bone loss. Pleckstrin homology (PH) domain and leucine-rich repeat protein phosphatase 1 (Phlpp1) regulates protein kinase C (PKC) and other proteins in the control of bone mass. Germline Phlpp1 deficiency reduces bone volume, but the mechanisms remain unknown. Here, we found that conditional Phlpp1 deletion in murine osteoclasts increases their numbers, but also enhances bone mass. Despite elevating osteoclasts, Phlpp1 deficiency did not increase serum markers of bone resorption, but elevated serum markers of bone formation. These results suggest that Phlpp1 suppresses osteoclast formation and production of paracrine factors controlling osteoblast activity. Phlpp1 deficiency elevated osteoclast numbers and size in ex vivo osteoclastogenesis assays, accompanied by enhanced expression of proto-oncogene C-Fms (C-Fms) and hyper-responsiveness to macrophage colony-stimulating factor (M-CSF) in bone marrow macrophages. Although Phlpp1 deficiency increased TRAP+ cell numbers, it suppressed actin-ring formation and bone resorption in these assays. We observed that Phlpp1 deficiency increases activity of PKCζ, a PKC isoform controlling cell polarity, and that addition of a PKCζ pseudosubstrate restores osteoclastogenesis and bone resorption of Phlpp1-deficient osteoclasts. Moreover, Phlpp1 deficiency increased expression of the bone-coupling factor collagen triple helix repeat-containing 1 (Cthrc1). Conditioned growth medium derived from Phlpp1-deficient osteoclasts enhanced mineralization of ex vivo osteoblast cultures, an effect that was abrogated by Cthrc1 knockdown. In summary, Phlpp1 critically regulates osteoclast numbers, and Phlpp1 deficiency enhances bone mass despite higher osteoclast numbers because it apparently disrupts PKCζ activity, cell polarity, and bone resorption and increases secretion of bone-forming Cthrc1.
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Affiliation(s)
- Anna M Mattson
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901
| | - Dana L Begun
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901
| | - David H H Molstad
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901
| | - Margaret A Meyer
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901
| | - Merry Jo Oursler
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55901.,Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota 55901.,Kogod Center on Aging, Mayo Clinic, Rochester, Minnesota 55901
| | - Jennifer J Westendorf
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901.,Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55901
| | - Elizabeth W Bradley
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901 .,Department of Biomedical Engineering and Physiology, Mayo Clinic, Rochester, Minnesota 55901
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46
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TLR4 counteracts BVRA signaling in human leukocytes via differential regulation of AMPK, mTORC1 and mTORC2. Sci Rep 2019; 9:7020. [PMID: 31065010 PMCID: PMC6504875 DOI: 10.1038/s41598-019-43347-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/16/2019] [Indexed: 12/30/2022] Open
Abstract
TLR4 is implicated in diseases associated with chronic low-grade inflammation, yet homeostatic signaling mechanisms that prevent and/or are affected by chronic TLR4 activation are largely uncharacterized. We recently reported that LPS/TLR4 activates in human leukocytes signaling intermediates (SI), abbreviated TLR4-SI, which include mTORC1-specific effectors and targets, and that leukocytes of patients with T2D or after cardiopulmonary bypass (CPB) expressed similar SI. Extending these previous findings, here we show that TLR4-SI expression post-CPB was associated with low serum bilirubin and reduced preoperative expression of biliverdin reductase A (BVRA), the enzyme that converts biliverdin to bilirubin, in patient’s leukocytes. Biliverdin inhibited TLR4 signaling in leukocytes and triggered phosphorylation of mTORC2-specific targets, including Akt, PKCζ, AMPKα-LKB1-TSC1/2, and their association with BVRA. Torin, PP242, and a PKCζ inhibitory peptide, but not rapamycin, prevented these biliverdin-induced responses and TLR4 inhibition. In contrast, LPS/TLR4 triggered decreases in BVRA, AMPKα and PKCζ expression, and an increase in haptoglobin, a heme binding protein, in leukocytes in vivo and in vitro, indicating that activated TLR4 may suppress biliverdin/BVRA signaling. Significantly, compared to non-diabetics, BVRA and PKCζ expression was low and haptoglobin was high in T2D patients leukocytes. Sustained TLR4 activation may deregulate homeostatic anti-inflammatory BVRA/mTORC2 signaling and thereby contribute to chronic inflammatory diseases.
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47
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Wu J, Ren B, Shi F, Hua P, Lin H. BMP and mTOR signaling in heterotopic ossification: Does their crosstalk provide therapeutic opportunities? J Cell Biochem 2019; 120:12108-12122. [PMID: 30989716 DOI: 10.1002/jcb.28710] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 03/17/2019] [Accepted: 03/22/2019] [Indexed: 12/23/2022]
Abstract
Heterotopic ossification (HO) refers to the pathological formation of ectopic bone in soft tissues, it occurs following severe trauma or in patients with a rare genetic disorder known as fibrodysplasia ossificans progressiva. The pathological process of HO formation is a two-step mechanism: inflammation and destruction of connective tissues, followed by bone formation. The latter is further subdivided into three stages: fibroproliferation/angiogenesis, chondrogenesis, and osteogenesis. Currently, therapeutic options for HO are limited. New potential therapeutics will most likely arise from a more detailed understanding of the signaling pathways implicated in each stage of ectopic bone formation and molecular targets that may be effective at both the early and late stages of HO. Bone morphogenetic protein (BMP) signaling is believed to play a key role in the overall HO process. Recently, the mammalian target of rapamycin (mTOR) signaling pathway has received attention as a critical pathway for chondrogenesis, osteogenesis, and HO. Inhibition of mTOR signaling has been shown to block trauma-induced and genetic HO. Intriguingly, recent studies have revealed crosstalk between mTOR and BMP signaling. Moreover, mTOR has emerged as a factor involved in the early hypoxic and inflammatory stages of HO. We will summarize the current knowledge of the roles of mTOR and BMP signaling in HO, with a particular focus on the crosstalk between mTOR and BMP signaling. We also discuss the activation of AMP activated protein kinase (AMPK) by the most widely used drug for type 2 diabetes, metformin, which exerts a dual negative regulatory effect on mTOR and BMP signaling, suggesting that metformin is a promising drug treatment for HO. The discovery of an mTOR-BMP signaling network may be a potential molecular mechanism of HO and may represent a novel therapeutic target for the pharmacological control of HO.
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Affiliation(s)
- Jianhui Wu
- Jiangxi Medical School, Nanchang University, Nanchang, Jiangx, China.,Nanchang Joint Programme, Queen Mary University of London, London, UK
| | - Bowen Ren
- Jiangxi Medical School, Nanchang University, Nanchang, Jiangx, China.,Nanchang Joint Programme, Queen Mary University of London, London, UK
| | - Fuli Shi
- Jiangxi Province Key Laboratory of Tumor Pathogens and Molecular Pathology and Department of Pathophysiology, School of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Ping Hua
- Jiangxi Province Key Laboratory of Tumor Pathogens and Molecular Pathology and Department of Pathophysiology, School of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Hui Lin
- Jiangxi Province Key Laboratory of Tumor Pathogens and Molecular Pathology and Department of Pathophysiology, School of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, China
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48
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Current Coverage of the mTOR Pathway by Next-Generation Sequencing Oncology Panels. Int J Mol Sci 2019; 20:ijms20030690. [PMID: 30764584 PMCID: PMC6387057 DOI: 10.3390/ijms20030690] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 01/28/2019] [Accepted: 01/29/2019] [Indexed: 12/19/2022] Open
Abstract
The mTOR pathway is in the process of establishing itself as a key access-point of novel oncological drugs and targeted therapies. This is also reflected by the growing number of mTOR pathway genes included in commercially available next-generation sequencing (NGS) oncology panels. This review summarizes the portfolio of medium sized diagnostic, as well as research destined NGS panels and their coverage of the mTOR pathway, including 16 DNA-based panels and the current gene list of Foundation One as a major reference entity. In addition, we give an overview of interesting, mTOR-associated somatic mutations that are not yet incorporated. Especially eukaryotic translation initiation factors (eIFs), a group of mTOR downstream proteins, are on the rise as far as diagnostics and drug targeting in precision medicine are concerned. This review aims to raise awareness for the true coverage of NGS panels, which should be valuable in selecting the ideal platform for diagnostics and research.
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Boutouja F, Stiehm CM, Platta HW. mTOR: A Cellular Regulator Interface in Health and Disease. Cells 2019; 8:cells8010018. [PMID: 30609721 PMCID: PMC6356367 DOI: 10.3390/cells8010018] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 12/25/2018] [Accepted: 01/01/2019] [Indexed: 12/19/2022] Open
Abstract
The mechanistic target of Rapamycin (mTOR) is a ubiquitously-conserved serine/threonine kinase, which has a central function in integrating growth signals and orchestrating their physiologic effects on cellular level. mTOR is the core component of differently composed signaling complexes that differ in protein composition and molecular targets. Newly identified classes of mTOR inhibitors are being developed to block autoimmune diseases and transplant rejections but also to treat obesity, diabetes, and different types of cancer. Therefore, the selective and context-dependent inhibition of mTOR activity itself might come into the focus as molecular target to prevent severe diseases and possibly to extend life span. This review provides a general introduction to the molecular composition and physiologic function of mTOR complexes as part of the Special Issue “2018 Select Papers by Cells’ Editorial Board Members”.
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Affiliation(s)
- Fahd Boutouja
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801 Bochum, Germany.
| | - Christian M Stiehm
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801 Bochum, Germany.
| | - Harald W Platta
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801 Bochum, Germany.
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Abstract
Mammalian target of rapamycin (mTOR) is a conserved serine/threonine kinase of the phosphatidylinositol kinase-related kinase family that regulates cell growth, metabolism, and autophagy. Extensive research has linked mTOR to several human diseases including cancer, neurodegenerative disorders, and aging. In this review, recent publications regarding the mechanisms underlying the role of mTOR in female reproduction under physiological and pathological conditions are summarized. Moreover, we assess whether strategies to improve or suppress mTOR expression could have therapeutic potential for reproductive diseases like premature ovarian failure, polycystic ovarian syndrome, and endometriosis.
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