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Sun X, Zhao X, Xu Y, Yan Y, Han L, Wei M, He M. Potential therapeutic strategy for cancer: Multi-dimensional cross-talk between circRNAs and parental genes. Cancer Lett 2024; 588:216794. [PMID: 38453043 DOI: 10.1016/j.canlet.2024.216794] [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: 01/09/2024] [Revised: 02/27/2024] [Accepted: 03/04/2024] [Indexed: 03/09/2024]
Abstract
In many ways, circular RNAs (circRNAs) have been demonstrated to be crucial in the onset and advancement of cancer throughout the last ten years and have become a new focus of intense research in the field of RNAs. Accumulating studies have demonstrated that circRNAs can regulate parental gene expression via a variety of biological pathways. Furthermore, research into the complex interactions between circRNAs and their parental genes will shed light on their biological roles and open up new avenues for circRNAs' potential clinical translational uses. However, to date, multi-dimensional cross-talk between circRNAs and parental genes have not been systematically elucidated. Particularly intriguing is circRNA's exploration of tumor targeting, and potential therapeutic uses based on the parental gene regulation perspective. Here, we discuss their biogenesis, take a fresh look at the molecular mechanisms through which circRNAs control the expression of their parental genes in cancer. We further highlight We further highlight the latest circRNA clinical translational applications, including prognostic diagnostic markers, cancer vaccines, gDNA, and so on. Demonstrating the potential benefits and future applications of circRNA therapy.
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Affiliation(s)
- Xiaoyu Sun
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, Liaoning Province, China; Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, Shenyang, China.
| | - Xinyi Zhao
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, Liaoning Province, China; Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, Shenyang, China.
| | - Yan Xu
- Department of Urology, The First Hospital of China Medical University, Shenyang, China.
| | - Yuanyuan Yan
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, Liaoning Province, China; Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, Shenyang, China.
| | - Li Han
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, Liaoning Province, China; Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, Shenyang, China.
| | - Minjie Wei
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, Liaoning Province, China; Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, Shenyang, China; Liaoning Medical Diagnosis and Treatment Center, Liaoning Province, China.
| | - Miao He
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, Liaoning Province, China; Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, Liaoning Cancer Immune Peptide Drug Engineering Technology Research Center, Shenyang, China.
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Ghashghaei M, Liu Y, Ettles J, Bombaci G, Ramkumar N, Liu Z, Escano L, Miko SS, Kim Y, Waldron JA, Do K, MacPherson K, Yuen KA, Taibi T, Yue M, Arsalan A, Jin Z, Edin G, Karsan A, Morin GB, Kuchenbauer F, Perna F, Bushell M, Vu LP. Translation efficiency driven by CNOT3 subunit of the CCR4-NOT complex promotes leukemogenesis. Nat Commun 2024; 15:2340. [PMID: 38491013 PMCID: PMC10943099 DOI: 10.1038/s41467-024-46665-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 03/04/2024] [Indexed: 03/18/2024] Open
Abstract
Protein synthesis is frequently deregulated during tumorigenesis. However, the precise contexts of selective translational control and the regulators of such mechanisms in cancer is poorly understood. Here, we uncovered CNOT3, a subunit of the CCR4-NOT complex, as an essential modulator of translation in myeloid leukemia. Elevated CNOT3 expression correlates with unfavorable outcomes in patients with acute myeloid leukemia (AML). CNOT3 depletion induces differentiation and apoptosis and delayed leukemogenesis. Transcriptomic and proteomic profiling uncovers c-MYC as a critical downstream target which is translationally regulated by CNOT3. Global analysis of mRNA features demonstrates that CNOT3 selectively influences expression of target genes in a codon usage dependent manner. Furthermore, CNOT3 associates with the protein network largely consisting of ribosomal proteins and translation elongation factors in leukemia cells. Overall, our work elicits the direct requirement for translation efficiency in tumorigenesis and propose targeting the post-transcriptional circuitry via CNOT3 as a therapeutic vulnerability in AML.
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Affiliation(s)
- Maryam Ghashghaei
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
- Terry Fox Laboratory, British Columbia Cancer Research Centre Vancouver, Vancouver, Canada
| | - Yilin Liu
- Terry Fox Laboratory, British Columbia Cancer Research Centre Vancouver, Vancouver, Canada
- Department of Experimental Medicine, University of British Columbia, Vancouver, Canada
| | - James Ettles
- CRUK Beatson Institute, Glasgow, UK
- School of Cancer Sciences, University of Glasgow, Glasgow, UK
| | - Giuseppe Bombaci
- Department of Medicine, Indiana University Simon Comprehensive Cancer Center, Indianapolis, IN, USA
| | - Niveditha Ramkumar
- Terry Fox Laboratory, British Columbia Cancer Research Centre Vancouver, Vancouver, Canada
| | - Zongmin Liu
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
- Terry Fox Laboratory, British Columbia Cancer Research Centre Vancouver, Vancouver, Canada
| | - Leo Escano
- Terry Fox Laboratory, British Columbia Cancer Research Centre Vancouver, Vancouver, Canada
| | - Sandra Spencer Miko
- Genome Sciences Centre, British Columbia Cancer Research Centre, Vancouver, Canada
| | - Yerin Kim
- Terry Fox Laboratory, British Columbia Cancer Research Centre Vancouver, Vancouver, Canada
- Bioinformatics program, University of British Columbia, Vancouver, Canada
| | - Joseph A Waldron
- CRUK Beatson Institute, Glasgow, UK
- School of Cancer Sciences, University of Glasgow, Glasgow, UK
| | - Kim Do
- Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Kyle MacPherson
- Terry Fox Laboratory, British Columbia Cancer Research Centre Vancouver, Vancouver, Canada
| | - Katie A Yuen
- Terry Fox Laboratory, British Columbia Cancer Research Centre Vancouver, Vancouver, Canada
| | - Thilelli Taibi
- Terry Fox Laboratory, British Columbia Cancer Research Centre Vancouver, Vancouver, Canada
| | - Marty Yue
- Terry Fox Laboratory, British Columbia Cancer Research Centre Vancouver, Vancouver, Canada
| | - Aaremish Arsalan
- Terry Fox Laboratory, British Columbia Cancer Research Centre Vancouver, Vancouver, Canada
| | - Zhen Jin
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
- Terry Fox Laboratory, British Columbia Cancer Research Centre Vancouver, Vancouver, Canada
| | - Glenn Edin
- Terry Fox Laboratory, British Columbia Cancer Research Centre Vancouver, Vancouver, Canada
| | - Aly Karsan
- Genome Sciences Centre, British Columbia Cancer Research Centre, Vancouver, Canada
| | - Gregg B Morin
- Genome Sciences Centre, British Columbia Cancer Research Centre, Vancouver, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Florian Kuchenbauer
- Terry Fox Laboratory, British Columbia Cancer Research Centre Vancouver, Vancouver, Canada
| | - Fabiana Perna
- Department of Medicine, Indiana University Simon Comprehensive Cancer Center, Indianapolis, IN, USA
- Department of Blood and Marrow Transplant and Cellular Immunotherapy, Moffit Cancer Center, Tampa, FL, USA
| | - Martin Bushell
- CRUK Beatson Institute, Glasgow, UK
- School of Cancer Sciences, University of Glasgow, Glasgow, UK
| | - Ly P Vu
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada.
- Terry Fox Laboratory, British Columbia Cancer Research Centre Vancouver, Vancouver, Canada.
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Kochavi A, Lovecchio D, Faller WJ, Agami R. Proteome diversification by mRNA translation in cancer. Mol Cell 2023; 83:469-480. [PMID: 36521491 DOI: 10.1016/j.molcel.2022.11.014] [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: 09/19/2022] [Revised: 11/14/2022] [Accepted: 11/16/2022] [Indexed: 12/15/2022]
Abstract
mRNA translation is a highly conserved and tightly controlled mechanism for protein synthesis and is well known to be altered by oncogenes to promote cancer development. This distorted mRNA translation is accompanied by the vulnerability of cancer to inhibitors of key mRNA translation components. Novel studies also suggest that these alternations could be utilized for immunotherapy. Ribosome heterogeneity and alternative responses to nutrient shortages, which aid cancer growth and spread, are proposed to elicit aberrant protein production but may also result in previously unidentified therapeutic targets, such as the presentation of cancer-specific peptides at the surface of cancer cells (neoepitopes). This review will assess the driving forces in tRNA and ribosome function that underlie proteome diversification due to alterations in mRNA translation in cancer cells.
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Affiliation(s)
- Adva Kochavi
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands; Oncode Institute, the Netherlands
| | - Domenica Lovecchio
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands; Oncode Institute, the Netherlands
| | - William James Faller
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - Reuven Agami
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands; Oncode Institute, the Netherlands; Erasmus MC, Rotterdam University, Rotterdam, the Netherlands.
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Ruff A, Lewis M, Whalen M. Organotin and organochlorine toxicants activate key translational regulatory proteins in human immune cells. Arch Toxicol 2023; 97:469-493. [PMID: 36372856 PMCID: PMC9939003 DOI: 10.1007/s00204-022-03413-z] [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: 10/03/2022] [Accepted: 11/03/2022] [Indexed: 11/15/2022]
Abstract
Environmental contaminant exposures occur due to the widespread use of synthetic chemicals. Tributyltin (TBT), dibutyltin (DBT), and pentachlorophenol (PCP) are each used in a variety of applications, including antifouling paints and stabilizers in certain plastics. Each of these compounds has been found in human blood, as well as other tissues, and they have been shown to stimulate pro-inflammatory cytokine production in human immune cells, Inflammatory cytokines mediate response to injury or infection. However, if their levels are increased in the absence of an appropriate stimulus, chronic inflammation can occur. Chronic inflammation is associated with a number of pathologies including cancer. Stimulation of pro-inflammatory cytokine production by these toxicants is dependent on activation of ERK 1/2 and/or p38 MAPK pathways. MAPK pathways have the capacity to regulate translation by increasing phosphorylation of key translation regulatory proteins. There have been no previous studies examining the effects of TBT, DBT, or PCP on translation. The current study shows that ribosomal protein S6 (S6), eukaryotic initiation factor 4B (eIF4B), and eIF4E are phosphorylated (activated) and/or their total levels are elevated in response to each of these compounds at concentrations found in human blood. Activation/increased levels of translational proteins occurred at concentrations of the compounds that have been shown to elevate pro-inflammatory cytokine production, but where there is no increase in mRNA for those proteins was seen. Compound-stimulated increases in translation appear to be part of the mechanism by which they elevate protein production in immune cells.
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Affiliation(s)
- Amanda Ruff
- Department of Biology, Tennessee State University, Nashville, TN, 37209, USA
| | - Meaghan Lewis
- Department of Biology, Tennessee State University, Nashville, TN, 37209, USA
| | - Margaret Whalen
- Department of Chemistry, Tennessee State University, 3500 John A. Merritt Blvd., Nashville, TN, 37209, USA.
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5
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Luan L, Lu F, Wang X, Wang Y, Wang W, Yang Y, Chen G, Yao H, Shi X, Yuan Z, Zhou G, Zhang H, He S. The predictive value of RNA binding proteins in colon adenocarcinoma. J Gastrointest Oncol 2021; 12:1543-1557. [PMID: 34532109 DOI: 10.21037/jgo-21-318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 07/22/2021] [Indexed: 12/09/2022] Open
Abstract
Background RNA binding proteins (RBPs) play an important role in regulating post-transcriptional gene expression and have been reported to be closely associated with the occurrence and development of tumors. However, the effect of RBPs in colon cancer remains unclear. Methods We downloaded clinical information and transcriptome data of colon adenocarcinoma (COAD) from The Cancer Genome Atlas database (TCGA) database. After combining this data, we identified differentially expressed RBPs in normal and cancer tissues and subsequently performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Prognosis-related RBPs were identified via Cox regression analysis. The samples were randomly divided into two groups; an experimental group and a control group. A predictive model was constructed by dividing the experimental group into high- and low-risk subgroups based on the scores of the prognostic-related RBPs, and the prognosis of samples in these two subgroups was compared. Then, this model was applied to the control group. Finally, the model results were verified based on an online survival database and the Human Protein Atlas (HPA) database. Results A total of 469 differentially expressed RBPs were identified in normal and cancer tissues. Ten prognosis-related RBPs were determined by Cox regression analysis. In the prognostic prediction model, the prognosis of high-risk patients in the experimental group was worse than that in the low-risk group, and the same result was obtained in the control group. In addition, the risk score in the Cox regression analysis showed that the model could be used as an independent prognostic factor (P<0.001). The results of the online survival analysis tool, HPA database, and the model were consistent. Conclusions Some specific RBPs are significantly associated with the prognosis of patients with COAD, and this finding may provide important information for the future diagnosis and treatment of patients with COAD.
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Affiliation(s)
- Lipeng Luan
- Department of General Surgery, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Feng Lu
- Department of General Surgery, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Xiaochuan Wang
- Center of Hepatobiliary Pancreatic Disease, Xu Zhou Central Hospital, Xuzhou, China
| | - Yunliang Wang
- Department of General Surgery, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Wei Wang
- Department of Oncology, Shengli Hospital of Shengli Oilfield, Dongying, China
| | - Yong Yang
- Department of General Surgery, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Guoliang Chen
- Department of General Surgery, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Huihui Yao
- Department of General Surgery, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Xinyu Shi
- Department of General Surgery, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Zihan Yuan
- Department of General Surgery, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Guoqiang Zhou
- Department of Gastrointestinal Surgery, Changshu No. 2 Hospital, Suzhou, China
| | - Haitao Zhang
- Department of General Surgery, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Songbing He
- Department of General Surgery, the First Affiliated Hospital of Soochow University, Suzhou, China
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DNA Intercalators Inhibit Eukaryotic Ribosomal RNA Synthesis by Impairing the Initiation of Transcription. Genes (Basel) 2021; 12:genes12091412. [PMID: 34573394 PMCID: PMC8466728 DOI: 10.3390/genes12091412] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 09/09/2021] [Accepted: 09/10/2021] [Indexed: 01/11/2023] Open
Abstract
In eukaryotes, ribosome biogenesis is driven by the synthesis of the ribosomal RNA (rRNA) by RNA polymerase I (Pol-I) and is tightly linked to cell growth and proliferation. The 3D-structure of the rDNA promoter plays an important, yet not fully understood role in regulating rRNA synthesis. We hypothesized that DNA intercalators/groove binders could affect this structure and disrupt rRNA transcription. To test this hypothesis, we investigated the effect of a number of compounds on Pol-I transcription in vitro and in cells. We find that intercalators/groove binders are potent inhibitors of Pol-I specific transcription both in vitro and in cells, regardless of their specificity and the strength of its interaction with DNA. Importantly, the synthetic ability of Pol-I is unaffected, suggesting that these compounds are not targeting post-initiating events. Notably, the tested compounds have limited effect on transcription by Pol-II and III, demonstrating the hypersensitivity of Pol-I transcription. We propose that stability of pre-initiation complex and initiation are affected as result of altered 3D architecture of the rDNA promoter, which is well in line with the recently reported importance of biophysical rDNA promoter properties on initiation complex formation in the yeast system.
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Ahn SM, Kang S, Min DH. Direct Monitoring of Cancer-Associated mRNAs in Living Cells to Evaluate the Therapeutic RNAi Efficiency Using Fluorescent Nanosensor. ACS Sens 2019; 4:1174-1179. [PMID: 31002230 DOI: 10.1021/acssensors.8b01498] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cancer-associated mRNA (mRNA) is an important biomarker for early diagnosis, prognosis, and prediction of treatment responses. Despite recent developments in fluorescence live cell imaging, reliable detection and quantification of mRNA in living cells still remain challenging due to a complicated intracellular environment. Herein, we present a fluorescent nanosensor for live-cell monitoring of cancer-related mRNAs involved in the canonical Wnt/β-catenin signaling pathway. The nanosensor enables rapid and accurate assessment of gene downregulation efficiency in a dose- and time-dependent manner by measuring quantitative fluorescence signal corresponding to β-catenin or its target mRNA levels in living cells. It is expected that the fluorescent nanosensor will be applicable to high-throughput screening for the efficient drug discovery and insightful understanding of the molecular mechanisms of potential drug candidate for cancer treatment.
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Affiliation(s)
- Seong Min Ahn
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
- Center for RNA Research, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea
| | - Seounghun Kang
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
- Center for RNA Research, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea
| | - Dal-Hee Min
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
- Center for RNA Research, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea
- Institute of Biotherapeutics Convergence Technology, Lemonex Inc., Seoul, 08826, Republic of Korea
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8
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Xu L, Zhang H, Mei M, Du C, Huang X, Li J, Wang Y, Bao S, Zheng H. Phosphorylation of serine/arginine-rich splicing factor 1 at tyrosine 19 promotes cell proliferation in pediatric acute lymphoblastic leukemia. Cancer Sci 2018; 109:3805-3815. [PMID: 30320932 PMCID: PMC6272096 DOI: 10.1111/cas.13834] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 09/21/2018] [Accepted: 10/04/2018] [Indexed: 12/21/2022] Open
Abstract
Serine/arginine‐rich splicing factor 1 (SRSF1) has been linked to various human cancers including pediatric acute lymphoblastic leukemia (ALL). Our previous study has shown that SRSF1 potentially contributes to leukemogenesis; however, its underlying mechanism remains unclear. In this study, leukemic cells were isolated from pediatric ALL bone marrow samples, followed by immunoprecipitation assays and mass spectrometry analysis specific to SRSF1. Subcellular localization of the SRSF1 protein and its mutants were analyzed by immunofluorescence staining. Cell growth, colony formation, cell apoptosis, and the cell cycle were investigated using stable leukemic cell lines generated with lentivirus‐mediated overexpressed WT or mutant plasmids. Cytotoxicity of the Tie2 kinase inhibitor was also evaluated. Our results showed the phosphorylation of SRSF1 at tyrosine 19 (Tyr‐19) was identified in newly diagnosed ALL samples, but not in complete remission or normal control samples. Compared to the SRSF1 WT cells, the missense mutants of the Tyr‐19 phosphorylation affected the subcellular localization of SRSF1. In addition, the Tyr‐19 phosphorylation of SRSF1 also led to increased cell proliferation and enhanced colony‐forming properties by promoting the cell cycle. Remarkably, we further identified the kinase Tie2 as a potential therapeutic target in leukemia cells. In conclusion, we identify for the first time that the phosphorylation state of SRSF1 is linked to different phases in pediatric ALL. The Tyr‐19 phosphorylation of SRSF1 disrupts its subcellular localization and promotes proliferation in leukemia cells by driving cell‐cycle progression. Inhibitors targeting Tie2 kinase that could catalyze Tyr‐19 phosphorylation of SRSF1 offer a promising therapeutic target for treatment of pediatric ALL.
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Affiliation(s)
- Liting Xu
- Beijing Key Laboratory of Pediatric Hematology Oncology, National Key Discipline of Pediatrics, Ministry of Education, Key Laboratory of Major Diseases in Children, Ministry of Education, Hematology Oncology Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Han Zhang
- Beijing Key Laboratory of Pediatric Hematology Oncology, National Key Discipline of Pediatrics, Ministry of Education, Key Laboratory of Major Diseases in Children, Ministry of Education, Hematology Oncology Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Mei Mei
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Chaohao Du
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Xiahe Huang
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Jing Li
- Beijing Key Laboratory of Pediatric Hematology Oncology, National Key Discipline of Pediatrics, Ministry of Education, Key Laboratory of Major Diseases in Children, Ministry of Education, Hematology Oncology Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Yingchun Wang
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Shilai Bao
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Huyong Zheng
- Beijing Key Laboratory of Pediatric Hematology Oncology, National Key Discipline of Pediatrics, Ministry of Education, Key Laboratory of Major Diseases in Children, Ministry of Education, Hematology Oncology Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
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9
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Ras Suppresses TXNIP Expression by Restricting Ribosome Translocation. Mol Cell Biol 2018; 38:MCB.00178-18. [PMID: 30037981 DOI: 10.1128/mcb.00178-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 07/16/2018] [Indexed: 12/28/2022] Open
Abstract
Oncogenic Ras upregulates aerobic glycolysis to meet the bioenergetic and biosynthetic demands of rapidly growing cells. In contrast, thioredoxin-interacting protein (TXNIP) is a potent inhibitor of glucose uptake and is frequently downregulated in human cancers. Our laboratory previously discovered that Ras activation suppresses TXNIP transcription and translation. In this study, we developed a system to study how Ras affects TXNIP translation in the absence of transcriptional effects. We show that whereas Ras drives a global increase in protein translation, it suppresses TXNIP protein synthesis by reducing the rate at which ribosomes transit the coding region of TXNIP mRNA. To investigate the underlying mechanism(s), we randomized or optimized the codons in the TXNIP message without altering the TXNIP primary amino acid sequence. Translation from these mRNA variants was still repressed by Ras, implying that mRNA secondary structure, microRNAs (miRNAs), RNA binding proteins, or codon usage does not contribute to the blockade of TXNIP synthesis. Rather, we show that the N terminus of the growing TXNIP polypeptide is the target for Ras-dependent translational repression. Our work demonstrates how Ras suppresses TXNIP translation elongation in the face of a global upregulation of protein synthesis and provides new insight into Ras-dependent metabolic reprogramming.
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10
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Chellini L, Monteleone V, Lombari M, Caldarola S, Loreni F. The oncoprotein Myc controls the phosphorylation of S6 kinase and AKT through protein phosphatase 2A. J Cell Biochem 2018; 119:9878-9887. [PMID: 30132971 DOI: 10.1002/jcb.27309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 06/27/2018] [Indexed: 12/29/2022]
Abstract
This study focuses on the effects of Myc oncoprotein on the translational apparatus of the cell. Translation is an energy consuming process that involves a large number of accessory factors. The production of components of the protein synthesis machinery can be regulated at the transcriptional level by specific factors. It has been shown that the product of the oncogene Myc, a transcription factor frequently activated in cancer, can control translational activity through an increase in the transcription of the eIF4F complex components (eIF4E, eIF4AI, and eIF4GI). However, additional effects at the posttranslational level have also been described. For instance, it has been shown that Myc upregulation can induce mammalian target of rapamycin (mTOR)-dependent 4E-binding protein 1 (4E-BP1) hyperphosphorylation. We induced overexpression or inhibition of Myc through transfection of complementary DNA constructs or specific small interfering RNA in PC3 (prostate carcinoma) and HeLa (cervical carcinoma) cells. We have observed that overexpression of Myc causes an increase in 4E-BP1 phosphorylation and activation of protein synthesis. Unexpectedly, we detected a parallel decrease in the phosphorylation level of S6 kinase (in PC3 and HeLa) and AKT (in HeLa). We report evidence that these changes are mediated by an increase in protein phosphatase 2A activity.
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Affiliation(s)
- Lidia Chellini
- Department of Biology, University of Rome Tor Vergata, Rome, Italy.,Unit of Preclinical Models and New Therapeutic Agents, IRCCS-Regina Elena National Cancer Institute, Rome, Italy
| | | | - Malinska Lombari
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
| | - Sara Caldarola
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
| | - Fabrizio Loreni
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
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Xiong J, Su T, Qu Z, Yang Q, Wang Y, Li J, Zhou S. Triptolide has anticancer and chemosensitization effects by down-regulating Akt activation through the MDM2/REST pathway in human breast cancer. Oncotarget 2018; 7:23933-46. [PMID: 27004407 PMCID: PMC5029675 DOI: 10.18632/oncotarget.8207] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 03/02/2016] [Indexed: 12/28/2022] Open
Abstract
Triptolide has been shown to exhibit anticancer activity. However, its mechanism of action is not clearly defined. Herein we report a novel signaling pathway, MDM2/Akt, is involved in the anticancer mechanism of triptolide. We observed that triptolide inhibits MDM2 expression in human breast cancer cells with either wild-type or mutant p53. This MDM2 inhibition resulted in decreased Akt activation. More specifically, triptolide interfered with the interaction between MDM2 and the transcription factor REST to increase expression of the regulatory subunit of PI3-kinase p85 and consequently inhibit Akt activation. We further showed that, regardless of p53 status, triptolide inhibited proliferation, induced apoptosis, and caused G1 phase cell cycle arrest. Triptolide also enhanced the cytotoxic effect of doxorubicin. MDM2 inhibition plays a causative role in these effects. The inhibitory effect of triptolide on MDM2-mediated Akt activation was eliminated with MDM2 overexpression. MDM2-overexpressing tumor cells, in turn, were less susceptible to the anticancer and chemosensitization effects of triptolide than control cells. Triptolide also exhibited anticancer and chemosensitization effects in nude mouse xenograft model. When it was administered to tumor-bearing nude mice, triptolide inhibited tumor growth and enhanced the antitumor effects of doxorubicin. In summary, triptolide has anticancer and chemosensitization effects by down-regulating Akt activation through the MDM2/REST pathway in human breast cancer. Our study helps to elucidate the p53-independent regulatory function of MDM2 in Akt signaling, offering a novel view of the mechanism by which triptolide functions as an anticancer agent.
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Affiliation(s)
- Jing Xiong
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Tiefen Su
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhiling Qu
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Qin Yang
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yu Wang
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jiansha Li
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Sheng Zhou
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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12
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Oblinger JL, Burns SS, Huang J, Pan L, Ren Y, Shen R, Kinghorn AD, Welling DB, Chang LS. Overexpression of eIF4F components in meningiomas and suppression of meningioma cell growth by inhibiting translation initiation. Exp Neurol 2018; 299:299-307. [PMID: 28610844 PMCID: PMC5723558 DOI: 10.1016/j.expneurol.2017.06.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 06/03/2017] [Accepted: 06/09/2017] [Indexed: 10/19/2022]
Abstract
Meningiomas frequently display activation of the PI3K/AKT/mTOR pathway, leading to elevated levels of phospho-eukaryotic translation initiation factor 4E binding proteins, which enhances protein synthesis; however, it is not known whether inhibition of protein translation is an effective treatment option for meningiomas. We found that human meningiomas expressed high levels of the three components of the eukaryotic initiation factor 4F (eIF4F) translation initiation complex, eIF4A, eIF4E, and eIF4G. The expression of eIF4A and eIF4E was important in sustaining the growth of NF2-deficient benign meningioma Ben-Men-1 cells, as shRNA-mediated knockdown of these proteins strongly reduced cell proliferation. Among a series of 23 natural compounds evaluated, silvestrol, which inhibits eIF4A, was identified as being the most growth inhibitory in both primary meningioma and Ben-Men-1 cells. Silvestrol treatment of meningioma cells prominently induced G2/M arrest. Consistently, silvestrol significantly decreased the amounts of cyclins D1, E1, A, and B, PCNA, and Aurora A. In addition, total and phosphorylated AKT, ERK, and FAK, which have been shown to be important drivers for meningioma cell proliferation, were markedly lower in silvestrol-treated Ben-Men-1 cells. Our findings suggest that inhibiting protein translation could be a potential treatment for meningiomas.
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Affiliation(s)
- Janet L Oblinger
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA; Department of Otolaryngology-Head and Neck Surgery, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Sarah S Burns
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA; Department of Otolaryngology-Head and Neck Surgery, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Jie Huang
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA; Department of Otolaryngology-Head and Neck Surgery, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Li Pan
- Division of Medicinal Chemistry and Pharmacognosy, The Ohio State University College of Pharmacy, Columbus, OH, USA
| | - Yulin Ren
- Division of Medicinal Chemistry and Pharmacognosy, The Ohio State University College of Pharmacy, Columbus, OH, USA
| | - Rulong Shen
- Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - A Douglas Kinghorn
- Division of Medicinal Chemistry and Pharmacognosy, The Ohio State University College of Pharmacy, Columbus, OH, USA
| | - D Bradley Welling
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Long-Sheng Chang
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA; Department of Otolaryngology-Head and Neck Surgery, The Ohio State University College of Medicine, Columbus, OH, USA; Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA.
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13
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Behrens K, Maul K, Tekin N, Kriebitzsch N, Indenbirken D, Prassolov V, Müller U, Serve H, Cammenga J, Stocking C. RUNX1 cooperates with FLT3-ITD to induce leukemia. J Exp Med 2017; 214:737-752. [PMID: 28213513 PMCID: PMC5339673 DOI: 10.1084/jem.20160927] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 11/27/2016] [Accepted: 01/27/2017] [Indexed: 01/08/2023] Open
Abstract
Behrens et al. establish the interplay of activated FLT3 receptor and the phosphorylated RUNX1 transcription factor in uncoupling proliferation and differentiation signals in acute leukemia. These findings demonstrate that RUNX1 is a viable therapeutic target in FLT3-mutated AML. Acute myeloid leukemia (AML) is induced by the cooperative action of deregulated genes that perturb self-renewal, proliferation, and differentiation. Internal tandem duplications (ITDs) in the FLT3 receptor tyrosine kinase are common mutations in AML, confer poor prognosis, and stimulate myeloproliferation. AML patient samples with FLT3-ITD express high levels of RUNX1, a transcription factor with known tumor-suppressor function. In this study, to understand this paradox, we investigated the impact of RUNX1 and FLT3-ITD coexpression. FLT3-ITD directly impacts on RUNX1 activity, whereby up-regulated and phosphorylated RUNX1 cooperates with FLT3-ITD to induce AML. Inactivating RUNX1 in tumors releases the differentiation block and down-regulates genes controlling ribosome biogenesis. We identified Hhex as a direct target of RUNX1 and FLT3-ITD stimulation and confirmed high HHEX expression in FLT3-ITD AMLs. HHEX could replace RUNX1 in cooperating with FLT3-ITD to induce AML. These results establish and elucidate the unanticipated oncogenic function of RUNX1 in AML. We predict that blocking RUNX1 activity will greatly enhance current therapeutic approaches using FLT3 inhibitors.
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Affiliation(s)
- Kira Behrens
- Retroviral Pathogenesis, Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, 20251 Hamburg, Germany
| | - Katrin Maul
- Retroviral Pathogenesis, Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, 20251 Hamburg, Germany
| | - Nilgün Tekin
- Retroviral Pathogenesis, Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, 20251 Hamburg, Germany.,Virus Genomics, Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, 20251 Hamburg, Germany
| | - Neele Kriebitzsch
- Retroviral Pathogenesis, Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, 20251 Hamburg, Germany
| | - Daniela Indenbirken
- Viral Transformation, Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, 20251 Hamburg, Germany
| | | | - Ursula Müller
- Retroviral Pathogenesis, Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, 20251 Hamburg, Germany
| | - Hubert Serve
- Department of Medicine, Hematology/Oncology, Johann Wolfgang Goethe-University, 60590 Frankfurt am Main, Germany
| | - Jörg Cammenga
- Department of Hematology, Institute for Clinical and Experimental Medicine, Linköping University, 58185 Linköping, Sweden
| | - Carol Stocking
- Retroviral Pathogenesis, Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, 20251 Hamburg, Germany
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14
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Fan W, Wang W, Mao X, Chu S, Feng J, Xiao D, Zhou J, Fan S. Elevated levels of p-Mnk1, p-eIF4E and p-p70S6K proteins are associated with tumor recurrence and poor prognosis in astrocytomas. J Neurooncol 2016; 131:485-493. [PMID: 27900644 DOI: 10.1007/s11060-016-2327-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 11/08/2016] [Indexed: 10/20/2022]
Abstract
Malignant astrocytomas are able to invade neighboring and distant areas of the normal brain. Signaling pathway alterations play important role in the development of astrocytomas. Deregulation of eukaryotic translation initiation factor 4E (eIF4E) by MAP kinase-interacting kinases (Mnk) on Ser-209 directly or PI3K/mTOR/S6K pathway indirectly has a critical effect on promoting cellular proliferation, malignant transformation and metastasis. We examined and analyzed the correlation between expression of p-Mnk1, p-eIF4E and p-p70S6K proteins and clinicopathological features in 103 astrocytomas and 54 non-tumorous brain tissues. The results indicated that positive percentage of overexpression of p-Mnk1 and p-eIF4E proteins in astrocytomas were significantly higher than that of in the non-tumorous brain tissues (P < 0.05). Elevated p-Mnk1 and p-eIF4E and co-overexpressed three proteins were associated with tumor recurrence (P = 0.003, P = 0.006, P = 0.007, respectively). Overexpressed p-eIF4E significantly correlated with the tumor size (P = 0.019). In addition, overexpression of p-eIF4E and three proteins common expression were related to the WHO grade of astrocytomas (P = 0.001, P = 0.044 respectively). Spearman's rank correlation test further showed that the expression of p-Mnk1 was strongly positive correlated with the expression of p-eIF4E in astrocytomas (r = 0.294, P = 0.003). Besides, overexpression of p-eIF4E and co-expression of p-Mnk1, p-eIF4E and p-p70S6K proteins were inversely correlated with overall survival rates of astrocytomas. Multivariate Cox regression analysis further identified that the elevated p-eIF4E expression, three proteins common expression were correlated with unfavorable prognosis of astrocytomas regardless of ages and WHO grades. Taken together, overexpression of p-eIF4E and co-expression of p-Mnk1, p-eIF4E and p-p70S6K proteins could be used as novel independent poor prognostic biomarkers for patients with astrocytomas.
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Affiliation(s)
- Weibing Fan
- Department of Neurology, The Third Hospital of Changsha, Changsha, 410011, Hunan, China
| | - Weiyuan Wang
- Department of Pathology, The Second Xiangya Hospital of Central South University, Changsha, 410011, Hunan, China.
| | - Xinfa Mao
- Department of Neurology, The Third Hospital of Changsha, Changsha, 410011, Hunan, China
| | - Shuzhou Chu
- Department of Pathology, The Second Xiangya Hospital of Central South University, Changsha, 410011, Hunan, China
| | - Juan Feng
- Department of Pathology, The Second Xiangya Hospital of Central South University, Changsha, 410011, Hunan, China
| | - Desheng Xiao
- Department of Pathology, Xiangya School of Medicine, Central South University, Changsha, 410011, Hunan, China
| | - Jianhua Zhou
- Department of Pathology, Xiangya School of Medicine, Central South University, Changsha, 410011, Hunan, China
| | - Songqing Fan
- Department of Pathology, The Second Xiangya Hospital of Central South University, Changsha, 410011, Hunan, China.
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15
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Oleksiewicz MB, Thorup I, Nielsen HS, Andersen HV, Hegelund AC, Iversen L, Guldberg TS, Brinck PR, Sjogren I, Thinggaard UK, Jørgensen L, Jensen MB. Generalized Cellular Hypertrophy is Induced by a Dual-Acting PPAR Agonist in Rat Urinary Bladder Urothelium In Vivo. Toxicol Pathol 2016; 33:552-60. [PMID: 16076770 DOI: 10.1080/01926230500214657] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Some developmental dual-acting PPARα/γ agonists, such as ragaglitazar, have shown carcinogenic effects in the rodent urinary bladder urothelium after months-years of dosing. We examined early (precancerous) changes in the bladder urothelium of rats orally dosed with ragaglitazar, using a newly developed flow cytometric method. Following 3 weeks of oral ragaglitazar dosing, increases in physical size occurred in a generalized fashion in rat bladder urothelial cells, determined by flow cytometry. Protein/DNA measurements confirmed increased protein content of urothelial cells in the bladder, and hypertrophy was observed in the kidney pelvis urothelium by histopathology. In animals exhibiting urothelial hypertrophy, no cell cycle changes were detected in parallel samples of bladder urothelium. Interestingly, urothelial cells from normal rats were found to constitute a unique type of noncycling population, with high G2/M fractions. In summary, our findings showed that in the urothelium of ragaglitazar-treated animals, hypertrophy (increased size and protein content per cell) was an early change, that affected the whole bladder urothelial cell population. The urothelial hypertrophy was primary, i.e., occurred in the absence of similarly pronounced changes in cell cycle distributions. To our knowledge, this is the first report of a direct hypertrophic effect of a PPAR agonist. Urothelial hypertrophy might be a relevant early biological endpoint in mechanistic studies regarding the bladder-carcinogenic effect of PPAR agonists.
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Affiliation(s)
- Martin B Oleksiewicz
- Novo Nordisk A/S, Novo Nordisk Park, Department of Virology and Molecular Toxicology, Maalov, Denmark.
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16
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Phosphorylated 4EBP1 is associated with tumor progression and poor prognosis in Xp11.2 translocation renal cell carcinoma. Sci Rep 2016; 6:23594. [PMID: 27026382 PMCID: PMC4812307 DOI: 10.1038/srep23594] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/09/2016] [Indexed: 12/27/2022] Open
Abstract
Two main signaling pathways, PI3K-AKT-mTOR and RAS-MAPK, are involved in transmitting the proliferative signals which play critical roles in human cancers. However, the functions of these pathways in Xp11.2 RCC remain undefined. This study aimed to explore the expression of mTOR and MAPK cascades in Xp11.2 RCC and to assess the prognostic significance of proteins evaluated. Immunohistochemistry was performed to evaluate the expression of 4EBP1, p-4EBP1, p-mTOR, p-S6K and p-MAPK in 36 adult Xp11.2 RCC patients who were confirmed by FISH assay. Cox regression models were used to evaluate the prognostic value of all covariates. Among 36 assessed patients, 14 (38.9%), 26 (72.2%), 16 (44.4%), 19 (52.8%), and 9 (25.0%) patients showed high expression of 4EBP1, p-4EBP1, p-mTOR, p-S6K, and p-MAPK, respectively. We noted that p-4EBP1 expression was significantly correlated with lymph node metastases (P = 0.027). Multivariate analysis showed that high p-4EBP1 expression was an independent adverse prognostic factor for both PFS (HR = 33.750, P = 0.017) and OS (HR = 56.111, P = 0.026). Our findings suggest that p-4EBP1 may serve as a funnel factor that converge the upstream proliferative oncogenic signals. Effective inhibition of the pathways responsible for 4E-BP1 phosphorylation might be a useful strategy to improve the outcome of Xp11.2 RCC patients.
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17
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Marcus H, Attar-Schneider O, Dabbah M, Zismanov V, Tartakover-Matalon S, Lishner M, Drucker L. Mesenchymal stem cells secretomes' affect multiple myeloma translation initiation. Cell Signal 2016; 28:620-30. [PMID: 26976208 DOI: 10.1016/j.cellsig.2016.03.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 03/01/2016] [Accepted: 03/08/2016] [Indexed: 12/29/2022]
Abstract
Bone marrow mesenchymal stem cells' (BM-MSCs) role in multiple myeloma (MM) pathogenesis is recognized. Recently, we have published that co-culture of MM cell lines with BM-MSCs results in mutual modulation of phenotype and proteome (via translation initiation (TI) factors eIF4E/eIF4GI) and that there are differences between normal donor BM-MSCs (ND-MSCs) and MM BM-MSCs (MM-MSCs) in this crosstalk. Here, we aimed to assess the involvement of soluble BM-MSCs' (ND, MM) components, more easily targeted, in manipulation of MM cell lines phenotype and TI with specific focus on microvesicles (MVs) capable of transferring critical biological material. We applied ND and MM-MSCs 72h secretomes to MM cell lines (U266 and ARP-1) for 12-72h and then assayed the cells' (viability, cell count, cell death, proliferation, cell cycle, autophagy) and TI (factors: eIF4E, teIF4GI; regulators: mTOR, MNK1/2, 4EBP; targets: cyclin D1, NFκB, SMAD5, cMyc, HIF1α). Furthermore, we dissected the secretome into >100kDa and <100kDa fractions and repeated the experiments. Finally, MVs were isolated from the ND and MM-MSCs secretomes and applied to MM cell lines. Phenotype and TI were assessed. Secretomes of BM-MSCs (ND, MM) significantly stimulated MM cell lines' TI, autophagy and proliferation. The dissected secretome yielded different effects on MM cell lines phenotype and TI according to fraction (>100kDa- repressed; <100kDa- stimulated) but with no association to source (ND, MM). Finally, in analyses of MVs extracted from BM-MSCs (ND, MM) we witnessed differences in accordance with source: ND-MSCs MVs inhibited proliferation, autophagy and TI whereas MM-MSCs MVs stimulated them. These observations highlight the very complex communication between MM and BM-MSCs and underscore its significance to major processes in the malignant cells. Studies into the influential MVs cargo are underway and expected to uncover targetable signals in the regulation of the TI/proliferation/autophagy cascade.
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Affiliation(s)
- H Marcus
- Oncogenetic Laboratory, Tel Aviv University, Tel Aviv, Israel; Sackler faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - O Attar-Schneider
- Oncogenetic Laboratory, Tel Aviv University, Tel Aviv, Israel; Sackler faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - M Dabbah
- Oncogenetic Laboratory, Tel Aviv University, Tel Aviv, Israel; Sackler faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - V Zismanov
- Oncogenetic Laboratory, Tel Aviv University, Tel Aviv, Israel; Sackler faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - S Tartakover-Matalon
- Oncogenetic Laboratory, Tel Aviv University, Tel Aviv, Israel; Sackler faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - M Lishner
- Oncogenetic Laboratory, Tel Aviv University, Tel Aviv, Israel; Internal Medicine Department, Meir Medical Center, Kfar Saba, Tel Aviv University, Tel Aviv, Israel; Sackler faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - L Drucker
- Oncogenetic Laboratory, Tel Aviv University, Tel Aviv, Israel; Sackler faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
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18
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Marques AEM, Elias ST, Porporatti AL, Castilho RM, Squarize CH, De Luca Canto G, Guerra ENS. mTOR pathway protein immunoexpression as a prognostic factor for survival in head and neck cancer patients: a systematic review and meta-analysis. J Oral Pathol Med 2015; 45:319-28. [PMID: 26661562 DOI: 10.1111/jop.12390] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2015] [Indexed: 12/19/2022]
Abstract
BACKGROUND Several mTOR pathway proteins are involved in the regulation of cellular anabolism, growth, proliferation, and survival. Activated proteins in the mTOR pathway are deregulated in multiple types of cancers and could influence prognosis. However, it is unclear whether deregulation of mTOR pathway proteins serves a prognostic role in patients with head and neck cancer (HNC). Furthermore, proteins in the mTOR pathway may be important targets for anticancer therapy. The aim of this study was to summarize existing cohort studies to determine whether immunoexpression of mTOR pathway proteins are important prognostic factors for survival in patients with HNC. MATERIALS AND METHODS A systematic review was performed using the Cochrane, Lilacs, PubMed, ScienceDirect, Scopus, and Web of Science databases (up to 23 January 2015). A meta-analysis was conducted to measure the frequency of protein expression in head and neck cancer patient samples and the prognostic value of mTOR pathway proteins for overall survival (OS) and disease-free survival (DFS). RESULTS Twelve studies were included in our final analysis. The meta-analysis revealed that the frequency of overall expression of mTOR pathway proteins was 74.42% (CI: 63.3 to 84.0, P < 0.001, n = 2016 samples). The survival meta-analysis showed a pooled hazard ratio for OS and DFS of 1.44 (95% confidence interval [95% CI] 1.14-1.73) and 1.18 (95% CI 0.71-1.64), respectively. CONCLUSION This systematic review and meta-analysis support evidence that mTOR pathway proteins can be used as predictive markers for survival in patients with HNC because their expression was significantly associated with poor OS and short DFS.
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Affiliation(s)
| | - Silvia Taveira Elias
- Oral Histopathology Laboratory, Health Sciences Faculty, University of Brasília, Brasília, DF, Brazil
| | - André Luís Porporatti
- Department of Dentistry, Federal University of Santa Catarina, Florianópolis, SC, Brazil.,Department of Prosthodontics, Section of Orofacial Pain, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil
| | - Rogerio Moraes Castilho
- Epithelial Biology Laboratory, Department of Periodontics and Oral Medicine, Division of Oral Pathology, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Cristiane Helena Squarize
- Epithelial Biology Laboratory, Department of Periodontics and Oral Medicine, Division of Oral Pathology, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Graziela De Luca Canto
- Department of Dentistry, Federal University of Santa Catarina, Florianópolis, SC, Brazil.,Department of Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Eliete Neves Silva Guerra
- Oral Histopathology Laboratory, Health Sciences Faculty, University of Brasília, Brasília, DF, Brazil
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19
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Ooft ML, Braunius WW, Heus P, Stegeman I, van Diest PJ, Grolman W, Zuur CI, Willems SM. Prognostic significance of the EGFR pathway in nasopharyngeal carcinoma: a systematic review and meta-analysis. Biomark Med 2015; 9:997-1010. [PMID: 26441207 DOI: 10.2217/bmm.15.68] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVE To evaluate the prognostic impact of the EGF receptor (EGFR) pathway molecules and assess their clinical usefulness. METHODS We conducted a systematic review. Pubmed and EMBASE were searched January 2014. The prognostic relevance of EGFR, JAK, PI3K, PIK3CA, STAT3, STAT5, PTEN, AKT, mTOR, GRB2, SOS, RAF, RAS, MAPK, ERK, MEK and CCND1 in nasopharyngeal carcinoma was assessed. The outcomes considered were overall survival, disease-free survival and tumor-node-metastasis stage. Twenty-two studies were included. Risk of bias was evaluated. Meta-analysis for which pooled hazard ratios and 95% CIs were calculated. CONCLUSION EGFR overexpression predicts a worse overall survival and disease-free survival in nasopharyngeal carcinoma, but no specific causal pathway molecule could be identified.
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Affiliation(s)
- Marc L Ooft
- Department of Pathology, University Medical Center, Utrecht, The Netherlands
| | - Weibel W Braunius
- Department of Otolaryngology, University Medical Center, Utrecht, The Netherlands
| | - Paulien Heus
- Dutch Cochrane Center, Julius Center for Health Sciences & Primary Care, University Medical Center, Utrecht, The Netherlands
| | - Inge Stegeman
- Department of Otolaryngology, University Medical Center, Utrecht, The Netherlands
| | - Paul J van Diest
- Department of Pathology, University Medical Center, Utrecht, The Netherlands
| | - Wilko Grolman
- Department of Otolaryngology, University Medical Center, Utrecht, The Netherlands
| | - Charlotte I Zuur
- Department of Head & Neck Surgery & Oncology, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Stefan M Willems
- Department of Pathology, University Medical Center, Utrecht, The Netherlands
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20
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Ay A, Wilner N, Yildirim N. Mathematical modeling deciphers the benefits of alternatively-designed conserved activatory and inhibitory gene circuits. MOLECULAR BIOSYSTEMS 2015; 11:2017-30. [PMID: 25966646 DOI: 10.1039/c5mb00269a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cells employ a variety of mechanisms as a response to external signals to maintain cellular homeostasis. In this study, we examine four activatory and four inhibitory protein synthesis mechanisms at both population and single cell level that can be triggered by a transient external signal. Activation mechanisms result from the assumption that cells can employ four different modes to temporarily increase the levels of a protein: decreased mRNA degradation, increased mRNA synthesis, decreased protein degradation and increased protein synthesis. For the inhibition mechanisms it is assumed that a cell can reduce a protein's level through four ways: increased mRNA degradation, reduced mRNA synthesis, increased protein degradation and reduced protein synthesis. Deterministic and stochastic models were developed to analyze the dynamic responses of these eight mechanisms to a transient signal. Three different response metrics were used to measure different aspects of the response. These metrics are (i) mid-protein abundance (mP), (ii) time required for the protein to reach the mid-protein level (mT), and (iii) duration of response (D), which is defined as the total time for which the protein (P) abundance are above or below of mid-protein level. Our simulations show that of the activation mechanisms, the signal-dependent increase in mRNA synthesis and protein synthesis are more effective and faster, than the signal dependent decrease in mRNA and protein degradation. On the other hand, the mechanism involving signal dependent increase in protein synthesis is noisier than the signal dependent increase in mRNA synthesis in regard to all metrics used. Of the four inhibition mechanisms, the signal-dependent increase in the protein degradation is the most effective and fastest of the four inhibition mechanisms. It is also noisiest of the four inhibition mechanisms before the protein levels reach a steady state around 100 minutes.
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Affiliation(s)
- Ahmet Ay
- Departments of Biology and Mathematics, Colgate University, 13 Oak Dr. Hamilton, NY 13346, USA
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21
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Fittschen M, Lastres-Becker I, Halbach MV, Damrath E, Gispert S, Azizov M, Walter M, Müller S, Auburger G. Genetic ablation of ataxin-2 increases several global translation factors in their transcript abundance but decreases translation rate. Neurogenetics 2015; 16:181-92. [PMID: 25721894 PMCID: PMC4475250 DOI: 10.1007/s10048-015-0441-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 02/10/2015] [Indexed: 12/12/2022]
Abstract
Spinocerebellar ataxia type 2 (SCA2) and amyotrophic lateral sclerosis (ALS) are neurodegenerative disorders, caused or modified by an unstable CAG-repeat expansion in the SCA2 gene, which encodes a polyglutamine (polyQ) domain expansion in ataxin-2 (ATXN2). ATXN2 is an RNA-binding protein and interacts with the poly(A)-binding protein PABPC1, localizing to ribosomes at the rough endoplasmic reticulum. Under cell stress, ATXN2, PABPC1 and small ribosomal subunits are relocated to stress granules, where mRNAs are protected from translation and from degradation. It is unknown whether ATXN2 associates preferentially with specific mRNAs or how it modulates RNA processing. Here, we investigated the RNA profile of the liver and cerebellum from Atxn2 knockout (Atxn2 (-/-)) mice at two adult ages, employing oligonucleotide microarrays. Prominent increases were observed for Lsm12/Paip1 (>2-fold), translation modulators known as protein interactor/competitor of ATXN2 and for Plin3/Mttp (>1.3-fold), known as apolipoprotein modulators in agreement with the hepatosteatosis phenotype of the Atxn2 (-/-) mice. Consistent modest upregulations were also observed for many factors in the ribosome and the translation/secretion apparatus. Quantitative reverse transcriptase PCR in liver tissue validated >1.2-fold upregulations for the ribosomal biogenesis modulator Nop10, the ribosomal components Rps10, Rps18, Rpl14, Rpl18, Gnb2l1, the translation initiation factors Eif2s2, Eif3s6, Eif4b, Pabpc1 and the rER translocase factors Srp14, Ssr1, Sec61b. Quantitative immunoblots substantiated the increased abundance of NOP10, RPS3, RPS6, RPS10, RPS18, GNB2L1 in SDS protein fractions, and of PABPC1. In mouse embryonal fibroblasts, ATXN2 absence also enhanced phosphorylation of the ribosomal protein S6 during growth stimulation, while impairing the rate of overall protein synthesis rates, suggesting a block between the enhanced translation drive and the impaired execution. Thus, the physiological role of ATXN2 subtly modifies the abundance of cellular translation factors as well as global translation.
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Affiliation(s)
- M Fittschen
- Experimental Neurology, Goethe University Medical School, Theodor Stern Kai 7, 60590, Frankfurt am Main, Germany
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eIF4E as a control target for viruses. Viruses 2015; 7:739-50. [PMID: 25690796 PMCID: PMC4353914 DOI: 10.3390/v7020739] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/06/2015] [Accepted: 02/11/2015] [Indexed: 01/04/2023] Open
Abstract
Translation is a complex process involving diverse cellular proteins, including the translation initiation factor eIF4E, which has been shown to be a protein that is a point for translational regulation. Viruses require components from the host cell to complete their replication cycles. Various studies show how eIF4E and its regulatory cellular proteins are manipulated during viral infections. Interestingly, viral action mechanisms in eIF4E are diverse and have an impact not only on viral protein synthesis, but also on other aspects that are important for the replication cycle, such as the proliferation of infected cells and stimulation of viral reactivation. This review shows how some viruses use eIF4E and its regulatory proteins for their own benefit in order to spread themselves.
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23
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Park SJ, Ryu J, Kim IH, Choi YH, Nam TJ. Activation of the mTOR signaling pathway in breast cancer MCF‑7 cells by a peptide derived from Porphyra yezoensis. Oncol Rep 2014; 33:19-24. [PMID: 25333576 PMCID: PMC4254673 DOI: 10.3892/or.2014.3557] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 09/26/2014] [Indexed: 11/15/2022] Open
Abstract
Seaweeds have beneficial nutritional and medicinal properties. Several studies have examined the polysaccharides found in the extracts of Porphyra yezoensis (PPY), although the effects of particular proteins have not been reported, and peptides from the marine alga PPY function in antitumor cell signaling, although the precise mechanism is not well understood. Apoptosis plays an important role in cell death, which affects cell proliferation. Generally, regulation of apoptosis requires participation of the p53 and Bcl-2 family by the mammalian target of rapamycin (mTOR) pathway, which is activated in a variety of malignant cancers. Autophagy is another signaling pathway that leads to degradation of cellular components by lysosomal activity, and the relationship between autophagy and cancer has been of interest for several years. The present study investigated mTOR pathway activation in MCF-7 cells treated with 500 ng PPY for 24 h by assessing LC3 as a monitor of autophagy. We observed that the p53/NF-κB and mTOR pathways were affected by PPY, which contributes to our understanding of the functional relationship between the Bcl-2 family and mTOR under apoptotic conditions in MCF-7 cells.
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Affiliation(s)
- Su-Jin Park
- Department of Food and Science, Pukyong National University, Busan 608-737, Republic of Korea
| | - Jina Ryu
- Department of Food and Science, Pukyong National University, Busan 608-737, Republic of Korea
| | - In-Hye Kim
- Institute of Fisheries Science, Pukyong National University, Busan 619-911, Republic of Korea
| | - Youn-Hee Choi
- Institute of Fisheries Science, Pukyong National University, Busan 619-911, Republic of Korea
| | - Taek-Jeong Nam
- Department of Food and Science, Pukyong National University, Busan 608-737, Republic of Korea
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24
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Activation of Akt/mTOR pathway is associated with poor prognosis of nasopharyngeal carcinoma. PLoS One 2014; 9:e106098. [PMID: 25165983 PMCID: PMC4148345 DOI: 10.1371/journal.pone.0106098] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 07/23/2014] [Indexed: 12/21/2022] Open
Abstract
Nasopharyngeal carcinoma (NPC) is a malignant tumor of the head and neck region, which frequently occurs in Southeast Asia, especially in the south of China. It is known that the mammalian target of rapamycin (mTOR) pathway plays a central role in regulating cellular functions, including proliferation, growth, survival, mobility, and angiogenesis. Aberrant expression of the mTOR signaling pathway molecules has been found in many types of cancer. However, whether the alterations of p-Akt, p-p70S6K and p-4EBP1 protein expression are associated with clinicopathological features and prognostic implications in NPC have not been reported. The purposes of the present study are to investigate the association between the expression of p-Akt, p-p70S6K and p-4EBP1 proteins and clinicopathological features in NPC by immunohistochemistry. The results showed that the positive percentage of p-Akt, p-p70S6K and p-4EBP1 proteins expression in NPC (47.2%, 73.0% and 61.7%, respectively) was significantly higher than that in the non-cancerous nasopharyngeal control tissue (33.3%, 59.1% and 47.0%, respectively). There was a significantly higher positive expression of p-Akt in undifferentiated non-keratinizing nasopharyngeal carcinoma than that in differentiated non-keratinizing nasopharyngeal carcinoma (P = 0.014). Additionally, positive expression of p-p70S6K and p-4EBP1 proteins, and positive expression of either of p-Akt, p-p70S6K and p-4EBP1 were significantly correlated inversely with overall survival rates of NPC patients (P = 0.023, P = 0.033, P = 0.008, respectively). Spearman’s rank correlation test showed that expression of p-Akt in NPC was significantly associated with expression of p-p70S6K (r = 0.263, P<0.001) and p-4EBP1(r = 0.284, P<0.001). Also there was an obviously positive association between expression of p-p70S6K and p-4EBP1 proteins in NPC (r = 0.286, P<0.001). Multivariate Cox regression analysis further identified positive expression of p-4EBP1 and p-p70S6K proteins were the independent poor prognostic factors for NPC (P = 0.043, P = 0.027, respectively). Taken together, high expression of p-p70S6K and p-4EBP1 proteins may act as valuable independent biomarkers to predict a poor prognosis of NPC.
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25
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Ilkow CS, Swift SL, Bell JC, Diallo JS. From scourge to cure: tumour-selective viral pathogenesis as a new strategy against cancer. PLoS Pathog 2014; 10:e1003836. [PMID: 24453963 PMCID: PMC3894191 DOI: 10.1371/journal.ppat.1003836] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Tumour mutations corrupt cellular pathways, and accumulate to disrupt, dysregulate, and ultimately avoid mechanisms of cellular control. Yet the very changes that tumour cells undergo to secure their own growth success also render them susceptible to viral infection. Enhanced availability of surface receptors, disruption of antiviral sensing, elevated metabolic activity, disengagement of cell cycle controls, hyperactivation of mitogenic pathways, and apoptotic avoidance all render the malignant cell environment highly supportive to viral replication. The therapeutic use of oncolytic viruses (OVs) with a natural tropism for infecting and subsequently lysing tumour cells is a rapidly progressing area of cancer research. While many OVs exhibit an inherent degree of tropism for transformed cells, this can be further promoted through pharmacological interventions and/or the introduction of viral mutations that generate recombinant oncolytic viruses adapted to successfully replicate only in a malignant cellular environment. Such adaptations that augment OV tumour selectivity are already improving the therapeutic outlook for cancer, and there remains tremendous untapped potential for further innovation.
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Affiliation(s)
- Carolina S. Ilkow
- Centre for Innovative Cancer Therapeutics, Ottawa Health Research Institute, Ottawa, Ontario, Canada
| | | | - John C. Bell
- Centre for Innovative Cancer Therapeutics, Ottawa Health Research Institute, Ottawa, Ontario, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
- * E-mail:
| | - Jean-Simon Diallo
- Centre for Innovative Cancer Therapeutics, Ottawa Health Research Institute, Ottawa, Ontario, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
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26
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Xiong Y, Lu QJ, Zhao J, Wu GY. Metformin inhibits growth of hepatocellular carcinoma cells by inducing apoptosis via mitochondrion-mediated pathway. Asian Pac J Cancer Prev 2013; 13:3275-9. [PMID: 22994747 DOI: 10.7314/apjcp.2012.13.7.3275] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Recently, population-based studies of type 2 diabetes patients have provided evidence that metformin treatment is associated with a reduced cancer incidence and mortality, but its mode of action remains unclear. Here we report effects of metformin on hepatocellular carcinoma (HCC) Hep-G2 cells and details of molecular mechanisms of metformin activity. Our research indicates that metformin displays anticancer activity against HCC through inhibition of the mTOR translational pathway in an AMPK-independent manner, leading to G1 arrest in the cell-cycle and subsequent cell apoptosis through the mitochondrion-dependent pathway. Furthermore, we showed that metformin strongly attenuated colony formation and dramatically inhibited Hep-G2 tumor growth in vivo. In conclusion, our studies suggested that metformin might have potential as a cytotoxic drug in the prevention and treatment of HCC.
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Affiliation(s)
- Yu Xiong
- Department of Hepatobiliary Surgery, Zhongshan Hospital, Xiamen University, Xiamen, China
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27
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Levidou G, Siakantaris M, Papadaki T, Papadavid E, Vassilakopoulos TP, Angelopoulou MK, Marinos L, Nikolaou V, Economidi A, Antoniou C, Patsouris E, Korkolopoulou P. A comprehensive immunohistochemical approach of AKT/mTOR pathway and p-STAT3 in mycosis fungoides. J Am Acad Dermatol 2013; 69:375-84. [PMID: 23685026 DOI: 10.1016/j.jaad.2013.04.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 12/19/2012] [Accepted: 04/08/2013] [Indexed: 01/11/2023]
Abstract
BACKGROUND Although the expression pattern of phosphorylated (p)-mTOR pathway components has attracted scientific interest in several neoplasms, to our knowledge, there is no published information regarding its significance in mycosis fungoides (MF). OBJECTIVE We sought to perform a comprehensive simultaneous assessment of key members of AKT/mTOR pathway along with p-extracellular signal-regulated kinase (ERK), NOTCH1, and p-STAT3 in patients with MF. METHODS In all, 54 skin biopsy specimens (21 tumors, 30 plaques, and 3 folliculotropic MF) from 50 patients with MF were analyzed immunohistochemically for p-mTOR, its upstream p-AKT, its downstream effectors p-p70S6K and p-4E-BP1, and for p-ERK1/2, NOTCH1, and p-STAT3. RESULTS p-mTOR was coexpressed with p-p70S6K in 67.3% of lesions, but coexpression with other molecules was less common. p-p70S6K and marginally NOTCH1 displayed higher H-scores in tumors than in plaques. Significant correlations were recorded between p-ERK and p-4E-BP1, as well as between NOTCH1 and p-p70S6K or p-4E-BP1. NOTCH1, p-4E-BP1, and p-p70S6K expression were associated with advanced stage. In survival analysis simultaneous overexpression of p-AKT and p-p70S6K, along with p-4E-BP1 positivity, adversely affected cancer-specific, disease-free, and progression-free survival in advanced-stage cases. LIMITATIONS A limitation may be the small number of cases included in our investigation, precluding multivariate survival analysis. CONCLUSIONS Activation of AKT/mTOR pathway in MF appears to be correlated with NOTCH1, p-ERK, and p-STAT3 and is implicated in the acquisition of a more aggressive phenotype. The combination of p-AKT, p-p70S6K, and p-4E-BP1 emerges as a significant potential prognostic marker in patients with advanced stage.
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Affiliation(s)
- Georgia Levidou
- Department of Pathology, University of Athens, Medical School, Athens, Greece.
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28
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Yang CW, Lee YZ, Hsu HY, Wu CM, Chang HY, Chao YS, Lee SJ. c-Jun-mediated anticancer mechanisms of tylophorine. Carcinogenesis 2013; 34:1304-14. [PMID: 23385061 DOI: 10.1093/carcin/bgt039] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Tylophorine, a phenanthroindolizidine alkaloid, is the major medicinal constituent of herb Tylophora indica. Tylophorine treatment increased the accumulation of c-Jun protein, a component of activator protein 1 (AP1), in carcinoma cells. An in vitro kinase assay revealed that the resultant c-Jun phosphorylation was primarily mediated via activated c-Jun N-terminal protein kinase (JNK). Moreover, flow cytometry indicated that ectopically overexpressed c-Jun in conjunction with tylophorine significantly increased the number of carcinoma cells that were arrested at the G1 phase. The tylophorine-mediated downregulation of cyclin A2 protein levels is known to be involved in the primary G1 arrest. Chromatin immunoprecipitation and reporter assays revealed that tylophorine enhanced the c-Jun downregulation of the cyclin A2 promoter activity upon increased binding of c-Jun to the deregulation AP1 site and decreased binding to the upregulation activating transcription factor (ATF) site in the cyclin A2 promoter, thereby reducing cyclin A2 expression. Further, biochemical studies using pharmacological inhibitors and RNA silencing approaches demonstrated that tylophorine-mediated elevation of the c-Jun protein level occurs primarily via two discrete prolonged signaling pathways: (i) the NF-κB/PKCδ_(MKK4)_JNK cascade, which phosphorylates c-Jun and increases its stability by slowing its ubiquitination, and (ii) the PI3K_PDK1_PP2A_eEF2 cascade, which sustains eukaryotic elongation factor 2 (eEF2) activity and thus c-Jun protein translation. To the best of our knowledge, this report is the first to demonstrate the involvement of c-Jun in the anticancer activity of tylophorine and the release of c-Jun translation from a global translational blockade via the PI3K_PDK1_eEF2 signaling cascade.
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Affiliation(s)
- Cheng-Wei Yang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan
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29
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Abstract
Primary glial brain tumors account for the majority of primary brain tumors in children. They are classified as low-grade gliomas (LGG) or high-grade gliomas (HGG), based on specific pathologic characteristics of the tumor, resulting in disparate clinical prognoses. Surgery is a mainstay of treatment for HGG, although it is not curative, and adjuvant therapy is required. Temozolomide, an oral imidazotetrazine prodrug, while considered standard of care for adult HGG, has not shown the same degree of benefit in the treatment of pediatric HGG. There are significant biologic differences that exist between adult and pediatric HGG, and targets specifically aimed at the biology in the pediatric population are required. Novel and specific therapies currently being investigated for pediatric HGG include small molecule inhibitors of epidermal growth factor receptor, platelet-derived growth factor receptor, histone deacetylase, the RAS/AKT pathway, telomerase, integrin, insulin-like growth factor receptor, and γ-secretase. Surgery is also the mainstay for LGG. There are defined front-line, multiagent chemotherapy regimens, but there are few proven second-line chemotherapy options for refractory patients. Approaches such as the inhibition of the mammalian target of rapamycin pathway, inhibition of MEK1 and 2, as well as BRAF, are discussed. Further research is required to understand the biology of pediatric gliomas as well as the use of molecularly targeted agents, especially in patients with surgically unresectable tumors.
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30
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Ranasinghe WKB, Xiao L, Kovac S, Chang M, Michiels C, Bolton D, Shulkes A, Baldwin GS, Patel O. The role of hypoxia-inducible factor 1α in determining the properties of castrate-resistant prostate cancers. PLoS One 2013; 8:e54251. [PMID: 23342109 PMCID: PMC3546972 DOI: 10.1371/journal.pone.0054251] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 12/10/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Castrate-resistant prostate cancer (CRPC) is a lethal condition in patients receiving androgen deprivation therapy for prostate cancer (PC). Despite numerous studies showing the expression of HIF1α protein under normoxia in PC cell lines, the role of this normoxic HIF1α expression in chemo-resistance and migration has not been investigated previously. As no method is currently available to determine which tumors will progress to CRPC, the role of HIF1α in PC and its potential for predicting the development of CRPC was also investigated. METHODS The effect of HIF1α protein knockdown on chemo-resistance and migration of PC3 cells was assessed by cell counting and Transwell assays, respectively. Translation efficiency of HIF1α mRNA was determined in PC cells using a HIF1α 5'UTR-luciferase construct. Clinical outcomes were correlated following the staining of 100 prostate tumors for HIF1α expression. RESULTS The CRPC-like cell lines (PC3 and DU145) expressed more HIF1α protein than an androgen sensitive cell line (LNCaP). Migration rate and chemo-resistance were higher in the PC3 cells and both were decreased when HIF1α expression was reduced. Increased translation of HIF1α mRNA may be responsible for HIF1α overexpression in PC3 cells. Patients whose tumors expressed HIF1α had significantly decreased metastasis-free survival and the patients who were on androgen-deprivation therapy had decreased CRPC-free survival on Kaplan-Meier analysis. On multivariate analysis HIF1α was an independent risk factor for progression to metastatic PC (Hazard ratio (HR) 9.8, p = 0.017) and development of CRPC (HR 10.0, p = 0.021) in patients on androgen-deprivation therapy. Notably the tumors which did not express HIF1α did not metastasize or develop CRPC. CONCLUSIONS HIF1α is likely to contribute to metastasis and chemo-resistance of CRPC and targeted reduction of HIF1α may increase the responsiveness of CRPCs to chemotherapy. Expression of HIF1α may be a useful screening tool for development of CRPC.
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Affiliation(s)
- Weranja K B Ranasinghe
- Department of Surgery, The University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
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31
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Andrews WJ, Panova T, Normand C, Gadal O, Tikhonova IG, Panov KI. Old drug, new target: ellipticines selectively inhibit RNA polymerase I transcription. J Biol Chem 2013; 288:4567-82. [PMID: 23293027 DOI: 10.1074/jbc.m112.411611] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Transcription by RNA polymerase I (Pol-I) is the main driving force behind ribosome biogenesis, a fundamental cellular process that requires the coordinated transcription of all three nuclear polymerases. Increased Pol-I transcription and the concurrent increase in ribosome biogenesis has been linked to the high rates of proliferation in cancers. The ellipticine family contains a number of potent anticancer therapeutic agents, some having progressed to stage I and II clinical trials; however, the mechanism by which many of the compounds work remains unclear. It has long been thought that inhibition of Top2 is the main reason behind the drugs antiproliferative effects. Here we report that a number of the ellipticines, including 9-hydroxyellipticine, are potent and specific inhibitors of Pol-I transcription, with IC(50) in vitro and in cells in the nanomolar range. Essentially, the drugs did not affect Pol-II and Pol-III transcription, demonstrating a high selectivity. We have shown that Pol-I inhibition occurs by a p53-, ATM/ATR-, and Top2-independent mechanism. We discovered that the drug influences the assembly and stability of preinitiation complexes by targeting the interaction between promoter recognition factor SL1 and the rRNA promoter. Our findings will have an impact on the design and development of novel therapeutic agents specifically targeting ribosome biogenesis.
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Affiliation(s)
- William J Andrews
- School of Biological Sciences, The Queen’s University Belfast, Belfast BT9 7BL, United Kingdom
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32
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Liu T, Nair SJ, Lescarbeau A, Belani J, Peluso S, Conley J, Tillotson B, O'Hearn P, Smith S, Slocum K, West K, Helble J, Douglas M, Bahadoor A, Ali J, McGovern K, Fritz C, Palombella VJ, Wylie A, Castro AC, Tremblay MR. Synthetic silvestrol analogues as potent and selective protein synthesis inhibitors. J Med Chem 2012; 55:8859-78. [PMID: 23025805 DOI: 10.1021/jm3011542] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Misregulation of protein translation plays a critical role in human cancer pathogenesis at many levels. Silvestrol, a cyclopenta[b]benzofuran natural product, blocks translation at the initiation step by interfering with assembly of the eIF4F translation complex. Silvestrol has a complex chemical structure whose functional group requirements have not been systematically investigated. Moreover, silvestrol has limited development potential due to poor druglike properties. Herein, we sought to develop a practical synthesis of key intermediates of silvestrol and explore structure-activity relationships around the C6 position. The ability of silvestrol and analogues to selectively inhibit the translation of proteins with high requirement on the translation-initiation machinery (i.e., complex 5'-untranslated region UTR) relative to simple 5'UTR was determined by a cellular reporter assay. Simplified analogues of silvestrol such as compounds 74 and 76 were shown to have similar cytotoxic potency and better ADME characteristics relative to those of silvestrol.
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Affiliation(s)
- Tao Liu
- Infinity Pharmaceuticals, Inc., 780 Memorial Drive, Cambridge, Massachusetts 02139, USA
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33
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Helmy K, Halliday J, Fomchenko E, Setty M, Pitter K, Hafemeister C, Holland EC. Identification of global alteration of translational regulation in glioma in vivo. PLoS One 2012; 7:e46965. [PMID: 23056544 PMCID: PMC3463531 DOI: 10.1371/journal.pone.0046965] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 09/07/2012] [Indexed: 12/17/2022] Open
Abstract
Post-transcriptional regulation of gene expression contributes to the protein output of a cell, however, methods for measuring translational regulation in complex in vivo systems are lacking. Here, we describe a sensitive method for measuring translational regulation in defined cell populations from heterogeneous tissue in vivo. We adapted the translating ribosome affinity purification (TRAP) methodology to measure the relative occupancy of individual mRNA transcripts in translating ribosomes in the Olig2-positive tumor cell population in a genetically engineered mouse model (GEM) of glioma. Global measurement of paired ribosome-bound and total cellular mRNA populations from tumor cells in vivo identified a broad distribution of relative ribosome occupancies amongst mRNA species that was highly reproducible across biological samples. Comparison of the translation state of glioma cells to non-transformed oligodendrocyte progenitor cells in normal brain identified global alteration of translation in tumor, and specifically of genes involved in cell division and synthetic metabolism. Furthermore, investigation of alteration in steady state translational efficiencies upon loss of PTEN, one of the most frequently mutated and deleted tumor suppressors in glioma, identified differential translation of proteins involved in cellular respiration, canonically regulated by PI3K/Akt signaling, and cellular glycosylation profiles, deregulation of which is known to be associated with tumor progression. Application of the translation efficiency profiling method described here to other biological contexts and conditions would extend our knowledge of the scope and impact of this important mode of gene regulation in complex in vivo systems.
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Affiliation(s)
- Karim Helmy
- Department of Cancer Biology and Genetics, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Brain Tumor Center, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Department of Medicine, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, United States of America
- Graduate School of Biomedical Sciences, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, United States of America
| | - John Halliday
- Department of Cancer Biology and Genetics, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Brain Tumor Center, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Gerstner Sloan-Kettering Graduate School of Biomedical Sciences, New York, New York, United States of America
| | - Elena Fomchenko
- Department of Cancer Biology and Genetics, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Brain Tumor Center, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Weill Medical College of Cornell University, New York, New York, United States of America
| | - Manu Setty
- Computational Biology Center, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Ken Pitter
- Department of Cancer Biology and Genetics, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Brain Tumor Center, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Weill Medical College of Cornell University, New York, New York, United States of America
| | - Christoph Hafemeister
- Department of Biology, New York University, New York, New York, United States of America
| | - Eric C. Holland
- Department of Cancer Biology and Genetics, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Brain Tumor Center, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Departments of Neurosurgery, Neurology and Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- * E-mail:
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34
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Drelon C, Berthon A, Ragazzon B, Tissier F, Bandiera R, Sahut-Barnola I, de Joussineau C, Batisse-Lignier M, Lefrançois-Martinez AM, Bertherat J, Martinez A, Val P. Analysis of the role of Igf2 in adrenal tumour development in transgenic mouse models. PLoS One 2012; 7:e44171. [PMID: 22952916 PMCID: PMC3429465 DOI: 10.1371/journal.pone.0044171] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 07/30/2012] [Indexed: 01/12/2023] Open
Abstract
Adrenal cortical carcinomas (ACC) are rare but aggressive tumours associated with poor prognosis. The two most frequent alterations in ACC in patients are overexpression of the growth factor IGF2 and constitutive activation of Wnt/β-catenin signalling. Using a transgenic mouse model, we have previously shown that constitutive active β-catenin is a bona fide adrenal oncogene. However, although all these mice developed benign adrenal hyperplasia, malignant progression was infrequent, suggesting that secondary genetic events were required for aggressive tumour development. In the present paper, we have tested IGF2 oncogenic properties by developing two distinct transgenic mouse models of Igf2 overexpression in the adrenal cortex. Our analysis shows that despite overexpression levels ranging from 7 (basal) to 87 (ACTH-induced) fold, Igf2 has no tumour initiating potential in the adrenal cortex. However, it induces aberrant accumulation of Gli1 and Pod1-positive progenitor cells, in a hedgehog-independent manner. We have also tested the hypothesis that Igf2 may cooperate with Wnt signalling by mating Igf2 overexpressing lines with mice that express constitutive active β-catenin in the adrenal cortex. We show that the combination of both alterations has no effect on tumour phenotype at stages when β-catenin-induced tumours are benign. However, there is a mild promoting effect at later stages, characterised by increased Weiss score and proliferation. Formation of malignant tumours is nonetheless a rare event, even when Igf2 expression is further increased by ACTH treatment. Altogether these experiments suggest that the growth factor IGF2 is a mild contributor to malignant adrenocortical tumourigenesis.
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Affiliation(s)
- Coralie Drelon
- Clermont Université, Université Blaise Pascal, GReD, Clermont-Ferrand, France
- CNRS UMR 6293, GReD, Aubière, France
- Inserm U1103, GReD, Aubière, France
| | - Annabel Berthon
- Clermont Université, Université Blaise Pascal, GReD, Clermont-Ferrand, France
- CNRS UMR 6293, GReD, Aubière, France
- Inserm U1103, GReD, Aubière, France
| | - Bruno Ragazzon
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, Paris, France
- Inserm U1016, Paris, France
- Assistance Publique Hôpitaux de Paris, Hôpital Cochin, Department of Endocrinology, Reference Center for Rare Adrenal Diseases, Paris, France
| | - Frédérique Tissier
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, Paris, France
- Inserm U1016, Paris, France
- Assistance Publique Hôpitaux de Paris, Hôpital Cochin, Department of Endocrinology, Reference Center for Rare Adrenal Diseases, Paris, France
| | | | - Isabelle Sahut-Barnola
- Clermont Université, Université Blaise Pascal, GReD, Clermont-Ferrand, France
- CNRS UMR 6293, GReD, Aubière, France
- Inserm U1103, GReD, Aubière, France
| | - Cyrille de Joussineau
- Clermont Université, Université Blaise Pascal, GReD, Clermont-Ferrand, France
- CNRS UMR 6293, GReD, Aubière, France
- Inserm U1103, GReD, Aubière, France
| | - Marie Batisse-Lignier
- Clermont Université, Université Blaise Pascal, GReD, Clermont-Ferrand, France
- CNRS UMR 6293, GReD, Aubière, France
- Inserm U1103, GReD, Aubière, France
- Centre Hospitalier Universitaire, Service d'Endocrinologie, Faculté de Médecine, Clermont-Ferrand, France
| | - Anne-Marie Lefrançois-Martinez
- Clermont Université, Université Blaise Pascal, GReD, Clermont-Ferrand, France
- CNRS UMR 6293, GReD, Aubière, France
- Inserm U1103, GReD, Aubière, France
| | - Jérôme Bertherat
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, Paris, France
- Inserm U1016, Paris, France
- Assistance Publique Hôpitaux de Paris, Hôpital Cochin, Department of Endocrinology, Reference Center for Rare Adrenal Diseases, Paris, France
| | - Antoine Martinez
- Clermont Université, Université Blaise Pascal, GReD, Clermont-Ferrand, France
- CNRS UMR 6293, GReD, Aubière, France
- Inserm U1103, GReD, Aubière, France
| | - Pierre Val
- Clermont Université, Université Blaise Pascal, GReD, Clermont-Ferrand, France
- CNRS UMR 6293, GReD, Aubière, France
- Inserm U1103, GReD, Aubière, France
- * E-mail:
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Ventoso I, Kochetov A, Montaner D, Dopazo J, Santoyo J. Extensive translatome remodeling during ER stress response in mammalian cells. PLoS One 2012; 7:e35915. [PMID: 22574127 PMCID: PMC3344847 DOI: 10.1371/journal.pone.0035915] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 03/26/2012] [Indexed: 12/03/2022] Open
Abstract
In this work we have described the translatome of two mammalian cell lines, NIH3T3 and Jurkat, by scoring the relative polysome association of ∼10,000 mRNA under normal and ER stress conditions. We have found that translation efficiencies of mRNA correlated poorly with transcript abundance, although a general tendency was observed so that the highest translation efficiencies were found in abundant mRNA. Despite the differences found between mouse (NIH3T3) and human (Jurkat) cells, both cell types share a common translatome composed by ∼800–900 mRNA that encode proteins involved in basic cellular functions. Upon stress, an extensive remodeling in translatomes was observed so that translation of ∼50% of mRNA was inhibited in both cell types, this effect being more dramatic for those mRNA that accounted for most of the cell translation. Interestingly, we found two subsets comprising 1000–1500 mRNA whose translation resisted or was induced by stress. Translation arrest resistant class includes many mRNA encoding aminoacyl tRNA synthetases, ATPases and enzymes involved in DNA replication and stress response such as BiP. This class of mRNA is characterized by high translation rates in both control and stress conditions. Translation inducible class includes mRNA whose translation was relieved after stress, showing a high enrichment in early response transcription factors of bZIP and zinc finger C2H2 classes. Unlike yeast, a general coordination between changes in translation and transcription upon stress (potentiation) was not observed in mammalian cells. Among the different features of mRNA analyzed, we found a relevant association of translation efficiency with the presence of upstream ATG in the 5′UTR and with the length of coding sequence of mRNA, and a looser association with other parameters such as the length and the G+C content of 5′UTR. A model for translatome remodeling during the acute phase of stress response in mammalian cells is proposed.
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Affiliation(s)
- Iván Ventoso
- Departamento de Biología Molecular, Universidad Autónoma de Madrid and Centro de Biología Molecular Severo Ochoa (UAM-CSIC), Cantoblanco, Madrid, Spain.
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Li L, Larabee SM, Chen S, Basiri L, Yamaguchi S, Zakaria A, Gallicano GI. Novel 5'TOPmRNAs regulated by ribosomal S6 kinase are important for cardiomyocyte development: S6 kinase suppression limits cardiac differentiation and promotes pluripotent cells toward a neural lineage. Stem Cells Dev 2012; 21:1538-48. [PMID: 22165977 DOI: 10.1089/scd.2011.0582] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Moving stem cells from bench to bedside has been a challenging task. Undermining this task is comprehending and optimizing the underlying regulatory mechanisms that drive differentiation of stem cells into desired cell and tissue types. Here we present evidence that ribosomal S6 kinase (S6K) is among the proteins upregulated as embryonic stem cells (ESCs) and human induced pluripotent stem cells differentiate into beating cardiomyocytes. We hypothesized that S6K plays a pivotal role in cardiomyogenesis, primarily because it regulates the translation of 3 cardiac-involved genes recently shown to have 5' terminal oligopyrimidine (5'TOP) sequences: connexin 43 (Cx43), desmoplakin (Dsp), and phosphatase and tensin homolog (PTEN). Along with another independent laboratory, we confirmed that S6K is indeed upregulated in beating ESC-derived cardiomyocytes compared to the surrounding nonbeating, differentiated cells. S6K short interfering RNA-transfected stem cell cultures indicate that inhibition of S6K strongly hinders development of cardiomyocyte beating and translation of Cx43, Dsp, and PTEN; these cardiac 5'TOP mRNAs were only properly translated in cells with S6K, supporting our hypothesis. An unexpected discovery took the role of S6K one step further: S6K-knockdown stem cell cultures developed significantly more neurons than seen in embryoid bodies subjected to a typical cardiac differentiation protocol. These results introduced the novel idea that in addition to its critical cardiac roles, S6K may be a significant factor that prevents stem cells from pursuing a neuronal pathway. Overall, results have indicated the necessity of S6K for normal stem cell cardiomyogenesis, as well as lowered S6K expression for stem cell neurogenesis.
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Affiliation(s)
- LeeAnn Li
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
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Sillé FCM, Thomas R, Smith MT, Conde L, Skibola CF. Post-GWAS functional characterization of susceptibility variants for chronic lymphocytic leukemia. PLoS One 2012; 7:e29632. [PMID: 22235315 PMCID: PMC3250464 DOI: 10.1371/journal.pone.0029632] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 12/01/2011] [Indexed: 11/18/2022] Open
Abstract
Recent genome-wide association studies (GWAS) have identified several gene variants associated with sporadic chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Many of these CLL/SLL susceptibility loci are located in non-coding or intergenic regions, posing a significant challenge to determine their potential functional relevance. Here, we review the literature of all CLL/SLL GWAS and validation studies, and apply eQTL analysis to identify putatively functional SNPs that affect gene expression that may be causal in the pathogenesis of CLL/SLL. We tested 12 independent risk loci for their potential to alter gene expression through cis-acting mechanisms, using publicly available gene expression profiles with matching genotype information. Sixteen SNPs were identified that are linked to differential expression of SP140, a putative tumor suppressor gene previously associated with CLL/SLL. Three additional SNPs were associated with differential expression of DACT3 and GNG8, which are involved in the WNT/β-catenin- and G protein-coupled receptor signaling pathways, respectively, that have been previously implicated in CLL/SLL pathogenesis. Using in silico functional prediction tools, we found that 14 of the 19 significant eQTL SNPs lie in multiple putative regulatory elements, several of which have prior implications in CLL/SLL or other hematological malignancies. Although experimental validation is needed, our study shows that the use of existing GWAS data in combination with eQTL analysis and in silico methods represents a useful starting point to screen for putatively causal SNPs that may be involved in the etiology of CLL/SLL.
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Affiliation(s)
- Fenna C. M. Sillé
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, California, United States of America
| | - Reuben Thomas
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, California, United States of America
| | - Martyn T. Smith
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, California, United States of America
| | - Lucia Conde
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, California, United States of America
| | - Christine F. Skibola
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, California, United States of America
- * E-mail:
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38
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He Y, Correa AM, Raso MG, Hofstetter WL, Fang B, Behrens C, Roth JA, Zhou Y, Yu L, Wistuba II, Swisher SG, Pataer A. The role of PKR/eIF2α signaling pathway in prognosis of non-small cell lung cancer. PLoS One 2011; 6:e24855. [PMID: 22102852 PMCID: PMC3213082 DOI: 10.1371/journal.pone.0024855] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 08/22/2011] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND In this study, we investigated whether PKR protein expression is correlated with mRNA levels and also evaluated molecular biomarkers that are associated with PKR, such as phosphorylated PKR (p-PKR) and phosphorylated eIF2α (p-eIF2α). METHODOLOGY AND FINDINGS We determined the levels of PKR protein expression and mRNA in 36 fresh primary lung tumor tissues by using Western blot analysis and real-time reverse-transcriptase PCR (RT-PCR), respectively. We used tissue microarrays for immunohistochemical evaluation of the expression of p-PKR and p-eIF2α proteins. We demonstrated that PKR mRNA levels are significantly correlated with PKR protein levels (Spearman's rho = 0.55, p<0.001), suggesting that PKR protein levels in tumor samples are regulated by PKR mRNA. We also observed that the patients with high p-PKR or p-eIF2α expression had a significantly longer median survival than those with little or no p-PKR or p-eIF2α expression (p = 0.03 and p = 0.032, respectively). We further evaluated the prognostic effect of combined expression of p-PKR plus PKR and p-eIF2α plus PKR and found that both combinations were strong independent prognostic markers for overall patient survival on stage I and all stage patients. CONCLUSIONS Our findings suggest that PKR protein expression may controlled by transcription level. Combined expression levels of PKR and p-PKR or p-eIF2α can be new markers for predicting the prognosis of patients with NSCLC.
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Affiliation(s)
- Yong He
- Department of Thoracic Surgery, Daping Hospital, Third Military Medical University, Chongqing, China
- Department of Thoracic and Cardiovascular Surgery, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Arlene M. Correa
- Department of Thoracic and Cardiovascular Surgery, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Maria Gabriela Raso
- Department of Pathology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Wayne L. Hofstetter
- Department of Thoracic and Cardiovascular Surgery, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Bingliang Fang
- Department of Thoracic and Cardiovascular Surgery, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Carmen Behrens
- Department of Thoracic Head and Neck Medical Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Jack A. Roth
- Department of Thoracic and Cardiovascular Surgery, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Yihong Zhou
- Department of Neurological Surgery and Biological Chemistry, University of California Irvine, Irvine, California, United States of America
| | - Liping Yu
- Ziren Research LLC, Irvine, California, United States of America
| | - Ignacio I. Wistuba
- Department of Pathology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
- Department of Thoracic Head and Neck Medical Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Stephen G. Swisher
- Department of Thoracic and Cardiovascular Surgery, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Apar Pataer
- Department of Thoracic and Cardiovascular Surgery, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
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Silva AS, Wood SH, van Dam S, Berres S, McArdle A, de Magalhães JP. Gathering insights on disease etiology from gene expression profiles of healthy tissues. ACTA ACUST UNITED AC 2011; 27:3300-5. [PMID: 21994229 DOI: 10.1093/bioinformatics/btr559] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
MOTIVATION Gene expression profiles have been widely used to study disease states. It may be possible, however, to gather insights into human diseases by comparing gene expression profiles of healthy organs with different disease incidence or severity. We tested this hypothesis and developed an approach to identify candidate genes associated with disease development by focusing on cancer incidence since it varies greatly across human organs. RESULTS We normalized organ-specific cancer incidence by organ weight and found that reproductive organs tend to have a higher mass-normalized cancer incidence, which could be due to evolutionary trade-offs. Next, we performed a genome-wide scan to identify genes whose expression across healthy organs correlates with organ-specific cancer incidence. We identified a large number of genes, including genes previously associated with tumorigenesis and new candidate genes. Most genes exhibiting a positive correlation with cancer incidence were related to ribosomal and transcriptional activity, translation and protein synthesis. Organs with enhanced transcriptional and translational activation may have higher cell proliferation and therefore be more likely to develop cancer. Furthermore, we found that organs with lower cancer incidence tend to express lower levels of known cancer-associated genes. Overall, these results demonstrate how genes and processes that predispose organs to specific diseases can be identified using gene expression profiles from healthy tissues. Our approach can be applied to other diseases and serve as foundation for further oncogenomic analyses. CONTACT jp@senescence.info SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- A Sofia Silva
- Integrative Genomics of Ageing Group, Institute of Integrative Biology, University of Liverpool, Liverpool, UK
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40
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Abstract
The widespread epidemic of obesity and type 2 diabetes has raised concern for the impact of these disorders as risk factors for cancer and has renewed the interest for studies regarding the involvement of hyperinsulinemia and insulin receptor (IR) in cancer progression. Overexpression of IR in cancer cells may explain their increased sensitivity to hyperinsulinemia. Moreover, IR isoform A (IR-A) together with autocrine production of its ligand IGF2 is emerging as an important mechanism of normal and cancer stem cell expansion and is a feature of several malignancies. De novo activation of the IR-A/IGF2 autocrine loop also represents a mechanism of resistance to anticancer therapies. Increasing knowledge of the IR role in cancer has important implications for cancer prevention, which should include control of insulin resistance and hyperinsulinemia in the population and meticulous evaluation of new antidiabetic drugs for their metabolic:mitogenic ratio. We are now aware that several anticancer treatments may induce or worsen insulin resistance that may limit therapy efficacy. Future anticancer therapies need to target the IR-A pathway in order to inhibit the tumor promoting effect of IR without impairing the metabolic effect of insulin.
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Affiliation(s)
- Antonino Belfiore
- Endocrinology Unit, Department of Clinical and Experimental Medicine, University Magna Graecia of Catanzaro, Campus Universitario, località Germaneto, 88100 Catanzaro, Italy.
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41
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Abstract
The mammalian target of rapamycin (mTOR) is a downstream effector of the PI3-K/Akt/mTOR pathway. Allosteric inhibitors of mTOR, everolimus and temsirolimus, have shown promising clinical activity in advanced renal cell carcinoma but their effect is far from durable and only a subset of patients experience substantial benefit from these agents. The PI3-K/Akt/mTOR pathway represents an intricate network of fine regulation and feedback loops, and resistance to allosteric mTOR inhibitors may be embedded within this complexity. In this article we highlight the molecular elements of the PI3-K/Akt/mTOR pathway, the clinical experience with everolimus and temsirolimus in advanced renal cell carcinoma, and the future directions in terms of sequential therapy, combinational therapy and development of novel therapeutic agents.
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Affiliation(s)
- Chiara Battelli
- Division of Hematology & Oncology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA
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42
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Knudsen KJ, Nelander Holm GM, Krabbe JS, Listov-Saabye N, Kiehr B, Dufva M, Svendsen JE, Oleksiewicz MB. Driving gradual endogenous c-myc overexpression by flow-sorting: intracellular signaling and tumor cell phenotype correlate with oncogene expression. Arch Toxicol 2011; 83:1061-74. [PMID: 19730820 DOI: 10.1007/s00204-009-0463-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Accepted: 08/20/2009] [Indexed: 11/28/2022]
Abstract
Insulin-exposed rat mammary cancer cells were flow sorted based on a c-myc reporter plasmid encoding a destabilized green fluorescent protein. Sorted cells exhibited gradual increases in c-myc levels. Cells overexpressing c-myc by only 10% exhibited phenotypic changes attributable to c-myc overexpression, such as cell cycle disturbances, increased cell size, and overexpression of the S6 ribosomal protein. Cells overexpressing c-myc by 70% exhibited additional phenotypic changes typical of c-myc overexpression, such as increased histone H3 phosphorylation, and reduced adherence. Sorted cells also exhibited overexpression of the IGF-1R, and slightly elevated expression of the IR. Increased susceptibility to the mitogenic effect of insulin was seen in a small proportion of the sorted cells, and insulin was more effective in activating the p44/42 MAPK pathway, but not the PI3K pathway, in the sorted cells than in the nonsorted cell population. To our knowledge, this is the first in vitro system allowing functional coupling between mitogenic signaling by a well-defined growth factor and gradual overexpression of the normal, endogenous c-myc gene. Thus, our flow-sorting approach provides an alternative modeling of the receptor-mediated carcinogenic process, compared to the currently used approaches of recombinant constitutive or conditional overexpression of oncogenic transmembrane receptor tyrosine kinases or oncogenic transcription factors.
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Affiliation(s)
- Kasper Jermiin Knudsen
- Institute for Micro and Nanotechnology, Technical University of Denmark, Lyngby, Denmark
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43
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Hvid H, Fels JJ, Kirk RK, Thorup I, Jensen HE, Hansen BF, Oleksiewicz MB. In Situ Phosphorylation of Akt and ERK1/2 in Rat Mammary Gland, Colon, and Liver Following Treatment with Human Insulin and IGF-1. Toxicol Pathol 2011; 39:623-40. [DOI: 10.1177/0192623311406936] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
High doses of insulin and the insulin analog AspB10 have been reported to increase mammary tumor incidence in female rats likely via receptor-mediated mechanisms, possibly involving enhanced IGF-1 receptor activation. However, insulin and IGF-1 receptor functionality and intracellular signaling in the rat mammary gland in vivo is essentially unexplored. The authors investigated the effect of a single subcutaneous dose of 600 nmol/kg human insulin or IGF-1 on Akt and ERK1/2 phosphorylation in rat liver, colon, and mammary gland. Rat tissues were examined by Western blotting and immunohistochemistry by phosphorylation-specific antibodies. Insulin as well as IGF-1 caused Akt phosphorylation in mammary epithelial cells, with myoepithelial and basal epithelial cells being most sensitive. IGF-1 caused stronger Akt phosphorylation than insulin in mammary gland epithelial cells. Phosphorylation of ERK1/2 was not influenced by insulin or IGF-1. Rather, in liver and mammary gland P-ERK1/2 appeared to correlate with estrous cycling, supporting that ERK1/2 has important physiological roles in these two organs. In short, these findings supported that the rat mammary gland epithelium expresses functional insulin and IGF-1 receptors and that phosphorylation of Akt as well as ERK1/2 may be of value in understanding the effects of exogenous insulin in the rat mammary gland and colon.
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Affiliation(s)
- Henning Hvid
- Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Denmark
- Pathology, Novo Nordisk A/S, Copenhagen, Denmark
| | | | - Rikke K. Kirk
- Histology and Delivery, Novo Nordisk A/S, Copenhagen, Denmark
| | - Inger Thorup
- Pathology, Novo Nordisk A/S, Copenhagen, Denmark
| | - Henrik E. Jensen
- Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Denmark
| | - Bo F. Hansen
- Insulin Biology, Novo Nordisk A/S, Copenhagen, Denmark
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Tornillo G, Bisaro B, Camacho-Leal MDP, Galiè M, Provero P, Di Stefano P, Turco E, Defilippi P, Cabodi S. p130Cas promotes invasiveness of three-dimensional ErbB2-transformed mammary acinar structures by enhanced activation of mTOR/p70S6K and Rac1. Eur J Cell Biol 2010; 90:237-48. [PMID: 20961652 DOI: 10.1016/j.ejcb.2010.09.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 07/22/2010] [Accepted: 09/01/2010] [Indexed: 11/29/2022] Open
Abstract
ErbB2 over-expression is detected in approximately 25% of invasive breast cancers and is strongly associated with poor patient survival. We have previously demonstrated that p130Cas adaptor is a crucial mediator of ErbB2 transformation. Here, we analysed the molecular mechanisms through which p130Cas controls ErbB2-dependent invasion in three-dimensional cultures of mammary epithelial cells. Concomitant p130Cas over-expression and ErbB2 activation enhance PI3K/Akt and Erk1/2 MAPK signalling pathways and promote invasion of mammary acini. By using pharmacological inhibitors, we demonstrate that both signalling cascades are required for the invasive behaviour of p130Cas over-expressing and ErbB2 activated acini. Erk1/2 MAPK and PI3K/Akt signalling triggers invasion through distinct downstream effectors involving mTOR/p70S6K and Rac1 activation, respectively. Moreover, in silico analyses indicate that p130Cas expression in ErbB2 positive human breast cancers significantly correlates with higher risk to develop distant metastasis, thus underlying the value of the p130Cas/ErbB2 synergism in regulating breast cancer invasion. In conclusion, high levels of p130Cas favour progression of ErbB2-transformed cells towards an invasive phenotype.
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Affiliation(s)
- Giusy Tornillo
- Molecular Biology Center, Department of Genetics, Biology and Biochemistry, University of Torino, Via Nizza 52, Torino, Italy
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Oleksiewicz MB, Bonnesen C, Hegelund AC, Lundby A, Holm GMN, Jensen MB, Krabbe JS. Comparison of intracellular signalling by insulin and the hypermitogenic AspB10 analogue in MCF-7 breast adenocarcinoma cells. J Appl Toxicol 2010; 31:329-41. [DOI: 10.1002/jat.1590] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 08/16/2010] [Accepted: 08/16/2010] [Indexed: 12/17/2022]
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Mounir Z, Koromilas AE. Uncovering the PKR pathway's potential for treatment of tumors. Future Oncol 2010; 6:643-5. [PMID: 20465378 DOI: 10.2217/fon.10.45] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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47
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Ezponda T, Pajares MJ, Agorreta J, Echeveste JI, López-Picazo JM, Torre W, Pio R, Montuenga LM. The Oncoprotein SF2/ASF Promotes Non–Small Cell Lung Cancer Survival by Enhancing Survivin Expression. Clin Cancer Res 2010; 16:4113-25. [DOI: 10.1158/1078-0432.ccr-10-0076] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Azim H, Azim HA, Escudier B. Targeting mTOR in cancer: renal cell is just a beginning. Target Oncol 2010; 5:269-80. [PMID: 20563661 DOI: 10.1007/s11523-010-0141-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Accepted: 06/10/2010] [Indexed: 12/31/2022]
Abstract
The mammalian target of rapamycin (mTOR) is a key regulator of cell growth and proliferation. The mTOR pathway integrates signals from nutrients, energy status and extracellular growth factors to regulate many processes, including cell cycle progression, angiogenesis, ribosome biogenesis, and metabolism. Growth factors such as insulin-like growth factor, epidermal growth factor and vascular endothelial growth factor bind to and activate their corresponding tyrosine kinase receptors (TKR) located on the cell surface, to induce signal transduction to the nucleus. TKR induces intracellular signaling cascades via the phosphorylation of the phosphatidylinositol 3-kinase, which in turn phosphorylates Akt. Of particular interest among the Akt targets is the downstream effect on mTOR, which is responsible for protein synthesis of molecules necessary for nutrient uptake, angiogenesis, ribosome biogenesis, cell growth, and proliferation. Growing evidence suggests that mTOR deregulation is associated with many types of human cancer. The importance of mTOR signaling in tumor biology is now widely accepted. Consequently, a number of agents that selectively target mTOR are being developed for cancer treatment and currently temsirolimus and everolimus are approved for the treatment of advanced renal cell cancer. However, the therapeutic benefit of mTOR inhibitors in the clinic may vary depending on the activation state of the different components of the mTOR pathway in a given case. Therefore it seems clear that predicting sensitivity to rapamycins in different cancers will likely require assessing multiple molecular markers related to mTOR signaling pathway, such as phosphatase and tensin homolog (PTEN), phospho-Akt, cytoplasmic p27, and phospho-S6 kinase.
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Affiliation(s)
- Hamdy Azim
- Department of Clinical Oncology, Cairo University Hospital, Cairo, Egypt
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49
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Livingstone M, Atas E, Meller A, Sonenberg N. Mechanisms governing the control of mRNA translation. Phys Biol 2010; 7:021001. [PMID: 20463379 DOI: 10.1088/1478-3975/7/2/021001] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The translation of cellular mRNA to protein is a tightly controlled process often deregulated in diseases such as cancer. Furthering our understanding of mRNA structural elements and the intracellular proteins and signaling pathways that affect protein expression is crucial in the development of new therapies. In this review, we discuss the current state-of-the-art of detecting and determining the role of mRNA sequence elements in regulating the initiation of mRNA translation and the therapeutic strategies that exploit this knowledge to treat disease.
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Affiliation(s)
- Mark Livingstone
- Department of Biochemistry and McGill Cancer Centre, McGill University, Montreal, QC H3A 1A3, Canada
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50
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Akar U, Ozpolat B, Mehta K, Lopez-Berestein G, Zhang D, Ueno NT, Hortobagyi GN, Arun B. Targeting p70S6K prevented lung metastasis in a breast cancer xenograft model. Mol Cancer Ther 2010; 9:1180-7. [PMID: 20423989 DOI: 10.1158/1535-7163.mct-09-1025] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Overexpression of p70S6K in breast cancer patients is associated with aggressive disease and poor prognosis. Recent studies showed that patients with breast cancer with increased p70S6K phosphorylation had poor survival and increased metastasis. The purpose of our study was to determine whether knockdown of p70S6K would inhibit cell growth, invasion, and metastasis in breast cancer. We therefore stably knocked down p70S6K expression in MDA-231, a highly metastatic breast cancer cell line, using a lentiviral short hairpin RNA (shRNA) based approach. Inhibition of p70S6K led to inhibition of cell growth, migration, and invasion in vitro. To determine the role of p70S6K in breast cancer tumorigenesis and metastasis, we used an MDA-231 orthotopic and metastatic animal model. In the orthotopic model, mice injected with MDA-231-p70S6K shRNA cells developed significantly smaller tumors than control mice injected with MDA-231 control shRNA cells (P < 0.01). No metastasis was observed in the p70S6K downregulated group, whereas lung metastasis was detected in all mice in the control group. To determine the role of p70S6K on growth and invasion, we tested downstream signaling targets by Western blot analysis. Knockdown of p70S6K inhibited phosphorylation of focal adhesion kinase, tissue transglutaminase 2, and cyclin D1 proteins, which promote cell growth, survival, and invasion. In addition, downregulation of p70S6K induced expression of PDCD4, a tumor-suppressor protein. In conclusion, we showed that p70S6K plays an important role in metastasis by regulating key proteins like cyclin D1, PDCD4, focal adhesion kinase, E-cadherin, beta-catenin, and tissue transglutaminase 2, which are essential for cell attachment, survival, invasion, and metastasis in breast cancer.
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Affiliation(s)
- Ugur Akar
- Department of Breast Medical Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
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