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Mars JC, Culjkovic-Kraljacic B, Borden KL. eIF4E orchestrates mRNA processing, RNA export and translation to modify specific protein production. Nucleus 2024; 15:2360196. [PMID: 38880976 PMCID: PMC11185188 DOI: 10.1080/19491034.2024.2360196] [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: 02/12/2024] [Accepted: 05/22/2024] [Indexed: 06/18/2024] Open
Abstract
The eukaryotic translation initiation factor eIF4E acts as a multifunctional factor that simultaneously influences mRNA processing, export, and translation in many organisms. Its multifactorial effects are derived from its capacity to bind to the methyl-7-guanosine cap on the 5'end of mRNAs and thus can act as a cap chaperone for transcripts in the nucleus and cytoplasm. In this review, we describe the multifactorial roles of eIF4E in major mRNA-processing events including capping, splicing, cleavage and polyadenylation, nuclear export and translation. We discuss the evidence that eIF4E acts at two levels to generate widescale changes to processing, export and ultimately the protein produced. First, eIF4E alters the production of components of the mRNA processing machinery, supporting a widescale reprogramming of multiple mRNA processing events. In this way, eIF4E can modulate mRNA processing without physically interacting with target transcripts. Second, eIF4E also physically interacts with both capped mRNAs and components of the RNA processing or translation machineries. Further, specific mRNAs are sensitive to eIF4E only in particular mRNA processing events. This selectivity is governed by the presence of cis-acting elements within mRNAs known as USER codes that recruit relevant co-factors engaging the appropriate machinery. In all, we describe the molecular bases for eIF4E's multifactorial function and relevant regulatory pathways, discuss the basis for selectivity, present a compendium of ~80 eIF4E-interacting factors which play roles in these activities and provide an overview of the relevance of its functions to its oncogenic potential. Finally, we summarize early-stage clinical studies targeting eIF4E in cancer.
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Affiliation(s)
- Jean-Clément Mars
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Montréal, QC, Canada
| | - Biljana Culjkovic-Kraljacic
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Montréal, QC, Canada
| | - Katherine L.B. Borden
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Montréal, QC, Canada
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Shao YY, Hsieh MS, Lee YH, Hsu HW, Wo RR, Wang HY, Cheng AL, Hsu CH. Cyclin dependent kinase 9 inhibition reduced programmed death-ligand 1 expression and improved treatment efficacy in hepatocellular carcinoma. Heliyon 2024; 10:e34289. [PMID: 39100490 PMCID: PMC11296019 DOI: 10.1016/j.heliyon.2024.e34289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 07/05/2024] [Accepted: 07/07/2024] [Indexed: 08/06/2024] Open
Abstract
The anti-programmed death-ligand 1 (PD-L1) antibody is a standard therapy for advanced hepatocellular carcinoma (HCC). Tumor expression of PD-L1 can be induced upon stimulus. Because cyclin-dependent kinase 9 (CDK9) inhibition reduces the expression of inducible proteins, we explored the influence of CDK9 inhibition on PD-L1 expression in HCC cells. We found that PD-L1 expression was low in HCC cells; however, IFN-γ treatment increased this expression. CDK9 inhibitors AZD4573 and atuveciclib reduced the IFN-γ induced PD-L1 expression in a dose-dependent manner. CDK9 knockdown yielded similar results, but CDK9 overexpression reversed the influence of the CDK9 inhibitors. In the orthotopic mouse model, mice treated with a CDK9 inhibitor and an anti-PD-L1 antibody had significantly smaller tumors and exhibited longer survival than mice treated with either agent. In conclusion, CDK9 inhibition could reduce the expression of PD-L1 in HCC cells. Using both CDK9 inhibitors and anti-PD-L1 antibodies is more effective than using either agent alone.
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Affiliation(s)
- Yu-Yun Shao
- Graduate Institute of Oncology, National Taiwan University College of Medicine, 1, Sec. 1, Ren'ai Rd., Taipei City, 10051, R.O.C, Taiwan
- Department of Oncology, National Taiwan University Hospital, 7, Chun-Shan S Road, Taipei City, 10002, R.O.C, Taiwan
- Department of Medical Oncology, National Taiwan University Cancer Center, 57, Ln. 155, Sec. 3, Keelung Rd., Taipei City, 106, R.O.C, Taiwan
| | - Min-Shu Hsieh
- Department of Pathology and Graduate Institute of Pathology, National Taiwan University College of Medicine, 1, Sec. 1, Ren'ai Rd., Taipei City, 10051, R.O.C, Taiwan
- Department of Pathology, National Taiwan University Hospital, 7, Chun-Shan S Road, Taipei City, 10002, R.O.C, Taiwan
- Department of Pathology, National Taiwan University Cancer Center, 57, Ln. 155, Sec. 3, Keelung Rd., Taipei City, 106, R.O.C, Taiwan
| | - Yi-Hsuan Lee
- Department of Pathology and Graduate Institute of Pathology, National Taiwan University College of Medicine, 1, Sec. 1, Ren'ai Rd., Taipei City, 10051, R.O.C, Taiwan
- Department of Pathology, National Taiwan University Hospital, 7, Chun-Shan S Road, Taipei City, 10002, R.O.C, Taiwan
| | - Hung-Wei Hsu
- Department of Oncology, National Taiwan University Hospital, 7, Chun-Shan S Road, Taipei City, 10002, R.O.C, Taiwan
| | - Rita Robin Wo
- Department of Oncology, National Taiwan University Hospital, 7, Chun-Shan S Road, Taipei City, 10002, R.O.C, Taiwan
| | - Han-Yu Wang
- Department of Oncology, National Taiwan University Hospital, 7, Chun-Shan S Road, Taipei City, 10002, R.O.C, Taiwan
| | - Ann-Lii Cheng
- Graduate Institute of Oncology, National Taiwan University College of Medicine, 1, Sec. 1, Ren'ai Rd., Taipei City, 10051, R.O.C, Taiwan
- Department of Internal Medicine, National Taiwan University College of Medicine, 1, Sec. 1, Ren'ai Rd., Taipei City, 10051, R.O.C, Taiwan
- Department of Oncology, National Taiwan University Hospital, 7, Chun-Shan S Road, Taipei City, 10002, R.O.C, Taiwan
- Department of Medical Oncology, National Taiwan University Cancer Center, 57, Ln. 155, Sec. 3, Keelung Rd., Taipei City, 106, R.O.C, Taiwan
| | - Chih-Hung Hsu
- Graduate Institute of Oncology, National Taiwan University College of Medicine, 1, Sec. 1, Ren'ai Rd., Taipei City, 10051, R.O.C, Taiwan
- Department of Oncology, National Taiwan University Hospital, 7, Chun-Shan S Road, Taipei City, 10002, R.O.C, Taiwan
- Department of Medical Oncology, National Taiwan University Cancer Center, 57, Ln. 155, Sec. 3, Keelung Rd., Taipei City, 106, R.O.C, Taiwan
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Ghasemi N, Azizi H. Exploring Myc puzzle: Insights into cancer, stem cell biology, and PPI networks. Gene 2024; 916:148447. [PMID: 38583818 DOI: 10.1016/j.gene.2024.148447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 03/13/2024] [Accepted: 04/04/2024] [Indexed: 04/09/2024]
Abstract
"The grand orchestrator," "Universal Amplifier," "double-edged sword," and "Undruggable" are just some of the Myc oncogene so-called names. It has been around 40 years since the discovery of the Myc, and it remains in the mainstream of cancer treatment drugs. Myc is part of basic helix-loop-helix leucine zipper (bHLH-LZ) superfamily proteins, and its dysregulation can be seen in many malignant human tumors. It dysregulates critical pathways in cells that are connected to each other, such as proliferation, growth, cell cycle, and cell adhesion, impacts miRNAs action, intercellular metabolism, DNA replication, differentiation, microenvironment regulation, angiogenesis, and metastasis. Myc, surprisingly, is used in stem cell research too. Its family includes three members, MYC, MYCN, and MYCL, and each dysfunction was observed in different cancer types. This review aims to introduce Myc and its function in the body. Besides, Myc deregulatory mechanisms in cancer cells, their intricate aspects will be discussed. We will look at promising drugs and Myc-based therapies. Finally, Myc and its role in stemness, Myc pathways based on PPI network analysis, and future insights will be explained.
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Affiliation(s)
- Nima Ghasemi
- Faculty of Biotechnology, Amol University of Special Modern Technologies, Amol, Iran
| | - Hossein Azizi
- Faculty of Biotechnology, Amol University of Special Modern Technologies, Amol, Iran.
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Chan KI, Zhang S, Li G, Xu Y, Cui L, Wang Y, Su H, Tan W, Zhong Z. MYC Oncogene: A Druggable Target for Treating Cancers with Natural Products. Aging Dis 2024; 15:640-697. [PMID: 37450923 PMCID: PMC10917530 DOI: 10.14336/ad.2023.0520] [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: 04/24/2023] [Accepted: 05/20/2023] [Indexed: 07/18/2023] Open
Abstract
Various diseases, including cancers, age-associated disorders, and acute liver failure, have been linked to the oncogene, MYC. Animal testing and clinical trials have shown that sustained tumor volume reduction can be achieved when MYC is inactivated, and different combinations of therapeutic agents including MYC inhibitors are currently being developed. In this review, we first provide a summary of the multiple biological functions of the MYC oncoprotein in cancer treatment, highlighting that the equilibrium points of the MYC/MAX, MIZ1/MYC/MAX, and MAD (MNT)/MAX complexes have further potential in cancer treatment that could be used to restrain MYC oncogene expression and its functions in tumorigenesis. We also discuss the multifunctional capacity of MYC in various cellular cancer processes, including its influences on immune response, metabolism, cell cycle, apoptosis, autophagy, pyroptosis, metastasis, angiogenesis, multidrug resistance, and intestinal flora. Moreover, we summarize the MYC therapy patent landscape and emphasize the potential of MYC as a druggable target, using herbal medicine modulators. Finally, we describe pending challenges and future perspectives in biomedical research, involving the development of therapeutic approaches to modulate MYC or its targeted genes. Patients with cancers driven by MYC signaling may benefit from therapies targeting these pathways, which could delay cancerous growth and recover antitumor immune responses.
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Affiliation(s)
- Ka Iong Chan
- Macao Centre for Research and Development in Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR 999078, China
| | - Siyuan Zhang
- Macao Centre for Research and Development in Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR 999078, China
| | - Guodong Li
- Macao Centre for Research and Development in Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR 999078, China
| | - Yida Xu
- Macao Centre for Research and Development in Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR 999078, China
| | - Liao Cui
- Guangdong Provincial Key Laboratory of Research and Development of Natural Drugs, School of Pharmacy, Guangdong Medical University, Zhanjiang 524000, China
| | - Yitao Wang
- Macao Centre for Research and Development in Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR 999078, China
| | - Huanxing Su
- Macao Centre for Research and Development in Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR 999078, China
| | - Wen Tan
- School of Pharmacy, Lanzhou University, Lanzhou 730000, China
| | - Zhangfeng Zhong
- Macao Centre for Research and Development in Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR 999078, China
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5
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Papadopoulos D, Uhl L, Ha SA, Eilers M. Beyond gene expression: how MYC relieves transcription stress. Trends Cancer 2023; 9:805-816. [PMID: 37422352 DOI: 10.1016/j.trecan.2023.06.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 06/14/2023] [Accepted: 06/15/2023] [Indexed: 07/10/2023]
Abstract
MYC oncoproteins are key drivers of tumorigenesis. As transcription factors, MYC proteins regulate transcription by all three nuclear polymerases and gene expression. Accumulating evidence shows that MYC proteins are also crucial for enhancing the stress resilience of transcription. MYC proteins relieve torsional stress caused by active transcription, prevent collisions between the transcription and replication machineries, resolve R-loops, and repair DNA damage by participating in a range of protein complexes and forming multimeric structures at sites of genomic instability. We review the key complexes and multimerization properties of MYC proteins that allow them to mitigate transcription-associated DNA damage, and propose that the oncogenic functions of MYC extend beyond the modulation of gene expression.
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Affiliation(s)
- Dimitrios Papadopoulos
- Theodor Boveri Institute, Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany; Mildred Scheel Early Career Center, University Hospital Würzburg, Würzburg, Germany
| | - Leonie Uhl
- Theodor Boveri Institute, Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Stefanie Anh Ha
- Theodor Boveri Institute, Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Martin Eilers
- Theodor Boveri Institute, Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
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Kotekar A, Singh AK, Devaiah BN. BRD4 and MYC: power couple in transcription and disease. FEBS J 2023; 290:4820-4842. [PMID: 35866356 PMCID: PMC9867786 DOI: 10.1111/febs.16580] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 06/16/2022] [Accepted: 07/20/2022] [Indexed: 01/26/2023]
Abstract
The MYC proto-oncogene and BRD4, a BET family protein, are two cardinal proteins that have a broad influence in cell biology and disease. Both proteins are expressed ubiquitously in mammalian cells and play central roles in controlling growth, development, stress responses and metabolic function. As chromatin and transcriptional regulators, they play a critical role in regulating the expression of a burgeoning array of genes, maintaining chromatin architecture and genome stability. Consequently, impairment of their function or regulation leads to many diseases, with cancer being the most predominant. Interestingly, accumulating evidence indicates that regulation of the expression and functions of MYC are tightly intertwined with BRD4 at both transcriptional and post-transcriptional levels. Here, we review the mechanisms by which MYC and BRD4 are regulated, their functions in governing various molecular mechanisms and the consequences of their dysregulation that lead to disease. We present a perspective of how the regulatory mechanisms for the two proteins could be entwined at multiple points in a BRD4-MYC nexus that leads to the modulation of their functions and disease upon dysregulation.
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Affiliation(s)
- Aparna Kotekar
- Experimental Immunology Branch, NCI, NIH, Bethesda, MD 20892, USA
| | - Amit Kumar Singh
- Experimental Immunology Branch, NCI, NIH, Bethesda, MD 20892, USA
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Guan Q, Chen Z, Yu F, Liu L, Huang Y, Wei G, Chiang CM, Wong J, Li J. MYC promotes global transcription in part by controlling P-TEFb complex formation via DNA-binding independent inhibition of CDK9 SUMOylation. SCIENCE CHINA. LIFE SCIENCES 2023; 66:2167-2184. [PMID: 37115490 PMCID: PMC10524883 DOI: 10.1007/s11427-022-2281-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 01/13/2023] [Indexed: 04/29/2023]
Abstract
MYC is an oncogenic transcription factor with a novel role in enhancing global transcription when overexpressed. However, how MYC promotes global transcription remains controversial. Here, we used a series of MYC mutants to dissect the molecular basis for MYC-driven global transcription. We found that MYC mutants deficient in DNA binding or known transcriptional activation activities can still promote global transcription and enhance serine 2 phosphorylation (Ser2P) of the RNA polymerase (Pol) II C-terminal domain (CTD), a hallmark of active elongating RNA Pol II. Two distinct regions within MYC can promote global transcription and Ser2P of Pol II CTD. The ability of various MYC mutants to promote global transcription and Ser2P correlates with their ability to suppress CDK9 SUMOylation and enhance positive transcription elongation factor b (P-TEFb) complex formation. We showed that MYC suppresses CDK9 SUMOylation by inhibiting the interaction between CDK9 and SUMO enzymes including UBC9 and PIAS1. Furthermore, MYC's activity in enhancing global transcription positively contributes to its activity in promoting cell proliferation and transformation. Together, our study demonstrates that MYC promotes global transcription, at least in part, by promoting the formation of the active P-TEFb complex via a sequence-specific DNA-binding activity-independent manner.
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Affiliation(s)
- Qingqing Guan
- Shanghai Key Laboratory of Regulatory Biology, Fengxian District Central Hospital-ECNU Joint Center of Translational Medicine, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Zhaosu Chen
- Shanghai Key Laboratory of Regulatory Biology, Fengxian District Central Hospital-ECNU Joint Center of Translational Medicine, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Fang Yu
- Department of Medicine, UF Health Cancer Center, University of Florida, Gainesville, FL, 32610, USA
| | - Lingling Liu
- CAS Key Laboratory of Computational Biology, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Yuanyong Huang
- Shanghai Key Laboratory of Regulatory Biology, Fengxian District Central Hospital-ECNU Joint Center of Translational Medicine, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Gang Wei
- CAS Key Laboratory of Computational Biology, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Cheng-Ming Chiang
- Simmons Comprehensive Cancer Center, Department of Pharmacology, and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Jiemin Wong
- Shanghai Key Laboratory of Regulatory Biology, Fengxian District Central Hospital-ECNU Joint Center of Translational Medicine, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, China.
| | - Jiwen Li
- Shanghai Key Laboratory of Regulatory Biology, Fengxian District Central Hospital-ECNU Joint Center of Translational Medicine, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, China.
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Illi B, Nasi S. Myc beyond Cancer: Regulation of Mammalian Tissue Regeneration. PATHOPHYSIOLOGY 2023; 30:346-365. [PMID: 37606389 PMCID: PMC10443299 DOI: 10.3390/pathophysiology30030027] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 07/28/2023] [Accepted: 07/31/2023] [Indexed: 08/23/2023] Open
Abstract
Myc is one of the most well-known oncogenes driving tumorigenesis in a wide variety of tissues. From the brain to blood, its deregulation derails physiological pathways that grant the correct functioning of the cell. Its action is carried out at the gene expression level, where Myc governs basically every aspect of transcription. Indeed, in addition to its role as a canonical, chromatin-bound transcription factor, Myc rules RNA polymerase II (RNAPII) transcriptional pause-release, elongation and termination and mRNA capping. For this reason, it is evident that minimal perturbations of Myc function mirror malignant cell behavior and, consistently, a large body of literature mainly focuses on Myc malfunctioning. In healthy cells, Myc controls molecular mechanisms involved in pivotal functions, such as cell cycle (and proliferation thereof), apoptosis, metabolism and cell size, angiogenesis, differentiation and stem cell self-renewal. In this latter regard, Myc has been found to also regulate tissue regeneration, a hot topic in the research fields of aging and regenerative medicine. Indeed, Myc appears to have a role in wound healing, in peripheral nerves and in liver, pancreas and even heart recovery. Herein, we discuss the state of the art of Myc's role in tissue regeneration, giving an overview of its potent action beyond cancer.
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Affiliation(s)
- Barbara Illi
- Institute of Molecular Biology and Pathology, National Research Council, c/o Department of Biology and Biotechnology “Charles Darwin”, Sapienza University of Rome, 00185 Rome, Italy
| | - Sergio Nasi
- Institute of Molecular Biology and Pathology, National Research Council, c/o Department of Biology and Biotechnology “Charles Darwin”, Sapienza University of Rome, 00185 Rome, Italy
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Gaur T, Poddutoori R, Khare L, Bagal B, Rashmi S, Patkar N, Tembhare P, Pg S, Shetty D, Dutt A, Zhang Q, Konopleva M, Platzbeckar U, Gupta S, Samajdar S, Ramchandra M, Khattry N, Hasan SK. Novel covalent CDK7 inhibitor potently induces apoptosis in acute myeloid leukemia and synergizes with Venetoclax. J Exp Clin Cancer Res 2023; 42:186. [PMID: 37507802 PMCID: PMC10386772 DOI: 10.1186/s13046-023-02750-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023] Open
Abstract
INTRODUCTION The emergence of resistance to the highly successful BCL2-directed therapy is a major unmet need in acute myeloid leukemia (AML), an aggressive malignancy with poor survival rates. Towards identifying therapeutic options for AML patients who progress on BCL2-directed therapy, we studied a clinical-stage CDK7 inhibitor XL102, which is being evaluated in solid tumors (NCT04726332). MATERIALS AND METHODS To determine the anti-proliferative effects of XL102, we performed experiments including time-resolved fluorescence resonance energy transfer, target occupancy, cell cycle and apoptosis-based assays. We also included genetically characterized primary myeloid blasts from de novo and relapsed/refractory AML patients. For mechanistic studies, CRISPR/Cas9 mediated knockout of CDK7 and c-Myc and immunoblotting were performed. NOD/SCID orthotropic and subcutaneous AML xenografts were used to determine anti-leukemic effects. To assess the synergistic effects of XL102 with Venetoclax, we performed RNA sequencing and gene set enrichment analysis using Venetoclax sensitive and resistant model systems. RESULTS XL102, a highly specific, orally bioavailable covalent inhibitor of CDK7. Inhibitory effect on CDK7 by XL102 in primary myeloid blasts (n = 54) was in nanomolar range (mean = 300 nM; range = 4.0-952 nM). XL102 treated AML cells showed a reduction in phosphorylation levels of Serine 2/5/7 at carboxy-terminal domain of RNA polymerase II. T-loop phosphorylation of CDK1(Thr161) and CDK2(Thr160) was inhibited by XL102 in dose-dependent manner leading to cell-cycle arrest. c-Myc downregulation and enhanced levels of p53 and p21 in XL102 treated cells were observed. Increased levels of p21 and activation of p53 by XL102 were mimicked by genetic ablation of CDK7, which supports that the observed effects of XL102 are due to CDK7 inhibition. XL102 treated AML xenografts showed remarkable reduction in hCD45 + marrow cells (mean = 0.60%; range = 0.04%-3.53%) compared to vehicle control (mean = 38.2%; range = 10.1%-78%), with corresponding increase in p53, p21 and decrease in c-Myc levels. The data suggests XL102 induces apoptosis in AML cells via CDK7/c-Myc/p53 axis. RNA-sequencing from paired Venetoclax-sensitive and Venetoclax-resistant cells treated with XL102 showed downregulation of genes involved in proliferation and apoptosis. CONCLUSION Taken together, XL102 with Venetoclax led to synergistic effects in overcoming resistance and provided a strong rationale for clinical evaluation of XL102 as a single agent and in combination with Venetoclax.
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Affiliation(s)
- Tarang Gaur
- Hasan Lab, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Navi, Mumbai, 410210, India
- Homi Bhabha National Institute (HBNI), Anushaktinagar, Mumbai, 400094, India
| | - Ramulu Poddutoori
- Aurigene Oncology Limited, Electronic City Hosur Road, Bangalore, 560100, India
| | - Leena Khare
- Aurigene Oncology Limited, Electronic City Hosur Road, Bangalore, 560100, India
| | - Bhausaheb Bagal
- Homi Bhabha National Institute (HBNI), Anushaktinagar, Mumbai, 400094, India
- Department of Medical Oncology, Tata Memorial Hospital, Tata Memorial Centre, Mumbai, 400014, India
| | - Sonal Rashmi
- Dutt Lab, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Navi, Mumbai, 410210, India
- Present Address: CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Nikhil Patkar
- Homi Bhabha National Institute (HBNI), Anushaktinagar, Mumbai, 400094, India
- Hematopathology Laboratory, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Navi, Mumbai, 410210, India
| | - Prashant Tembhare
- Homi Bhabha National Institute (HBNI), Anushaktinagar, Mumbai, 400094, India
- Hematopathology Laboratory, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Navi, Mumbai, 410210, India
| | - Subramanian Pg
- Homi Bhabha National Institute (HBNI), Anushaktinagar, Mumbai, 400094, India
- Hematopathology Laboratory, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Navi, Mumbai, 410210, India
| | - Dhanlaxmi Shetty
- Homi Bhabha National Institute (HBNI), Anushaktinagar, Mumbai, 400094, India
- Department of Cytogenetics, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Navi, Mumbai, 410210, India
| | - Amit Dutt
- Homi Bhabha National Institute (HBNI), Anushaktinagar, Mumbai, 400094, India
- Dutt Lab, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Navi, Mumbai, 410210, India
| | - Qi Zhang
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | | | - Uwe Platzbeckar
- Medical Clinic and Policlinic I, Hematology and Cellular Therapy, University Hospital Leipzig, Johannisallee 32, 04103, Leipzig, Germany
| | - Sudeep Gupta
- Homi Bhabha National Institute (HBNI), Anushaktinagar, Mumbai, 400094, India
- Department of Medical Oncology, Tata Memorial Hospital, Tata Memorial Centre, Mumbai, 400014, India
| | - Susanta Samajdar
- Aurigene Oncology Limited, Electronic City Hosur Road, Bangalore, 560100, India
| | - Murali Ramchandra
- Aurigene Oncology Limited, Electronic City Hosur Road, Bangalore, 560100, India
| | - Navin Khattry
- Homi Bhabha National Institute (HBNI), Anushaktinagar, Mumbai, 400094, India.
- Department of Medical Oncology, Tata Memorial Hospital, Tata Memorial Centre, Mumbai, 400014, India.
| | - Syed K Hasan
- Hasan Lab, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Navi, Mumbai, 410210, India.
- Homi Bhabha National Institute (HBNI), Anushaktinagar, Mumbai, 400094, India.
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Zhang W, Cao X, Zhong X, Wu H, Shi Y, Feng M, Wang YC, Ann D, Gwack Y, Yuan YC, Shang W, Sun Z. SRC2 controls CD4 + T cell activation via stimulating c-Myc-mediated upregulation of amino acid transporter Slc7a5. Proc Natl Acad Sci U S A 2023; 120:e2221352120. [PMID: 37094160 PMCID: PMC10160970 DOI: 10.1073/pnas.2221352120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 03/16/2023] [Indexed: 04/26/2023] Open
Abstract
T cell activation stimulates substantially increased protein synthesis activity to accumulate sufficient biomass for cell proliferation. The protein synthesis is fueled by the amino acids transported from the environment. Steroid nuclear receptor coactivator 2 (SRC2) is a member of a family of transcription coactivators. Here, we show that SRC2 recruited by c-Myc enhances CD4+ T cell activation to stimulate immune responses via upregulation of amino acid transporter Slc7a5. Mice deficient of SRC2 in T cells (SRC2fl/fl/CD4Cre) are resistant to the induction of experimental autoimmune encephalomyelitis (EAE) and susceptible to Citrobacter rodentium (C. rodentium) infection. Adoptive transfer of naive CD4+ T cells from SRC2fl/fl/CD4Cre mice fails to elicit EAE and colitis in Rag1/ recipients. Further, CD4+ T cells from SRC2fl/fl/CD4Cre mice display defective T cell proliferation, cytokine production, and differentiation both in vitro and in vivo. Mechanically, SRC2 functions as a coactivator to work together with c-Myc to stimulate the expression of amino acid transporter Slc7a5 required for T cell activation. Slc7a5 fails to be up-regulated in CD4+ T cells from SRC2fl/fl/CD4Cre mice, and forced expression of Slc7a5 rescues proliferation, cytokine production, and the ability of SRC2fl/fl/CD4Cre CD4+ T cells to induce EAE. Therefore, SRC2 is essential for CD4+ T cell activation and, thus, a potential drug target for controlling CD4+ T cell-mediated autoimmunity.
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Affiliation(s)
- Wencan Zhang
- Department of Immunology & Theranostics, Arthur Riggs Diabetes & Metabolism Research Institute, Beckman Research Institute of the City of Hope, Duarte, CA91010
| | - Xu Cao
- Department of Immuno-Oncology, Beckman Research Institute of the City of Hope, Duarte, CA91010
| | - Xiancai Zhong
- Department of Immunology & Theranostics, Arthur Riggs Diabetes & Metabolism Research Institute, Beckman Research Institute of the City of Hope, Duarte, CA91010
| | - Hongmin Wu
- Department of Immunology & Theranostics, Arthur Riggs Diabetes & Metabolism Research Institute, Beckman Research Institute of the City of Hope, Duarte, CA91010
| | - Yun Shi
- Department of Immunology & Theranostics, Arthur Riggs Diabetes & Metabolism Research Institute, Beckman Research Institute of the City of Hope, Duarte, CA91010
| | - Mingye Feng
- Department of Immuno-Oncology, Beckman Research Institute of the City of Hope, Duarte, CA91010
| | - Yi-Chang Wang
- Department of Diabetes Complication and Metabolism, Arthur Rigs Diabetes & Metabolism Research Institute, Beckman Research Institute of the City of Hope, Duarte, CA91010
| | - David Ann
- Department of Diabetes Complication and Metabolism, Arthur Rigs Diabetes & Metabolism Research Institute, Beckman Research Institute of the City of Hope, Duarte, CA91010
| | - Yousang Gwack
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Yate-Ching Yuan
- Division of Translational Bioinformatic, Bioinformatics Core, City of Hope, Duarte, CA91010
| | - Weirong Shang
- Department of Gynecology and Obsterics, School of Medicine, Emory University, Atlanta, GA30322
| | - Zuoming Sun
- Department of Immunology & Theranostics, Arthur Riggs Diabetes & Metabolism Research Institute, Beckman Research Institute of the City of Hope, Duarte, CA91010
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11
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Das SK, Lewis BA, Levens D. MYC: a complex problem. Trends Cell Biol 2023; 33:235-246. [PMID: 35963793 PMCID: PMC9911561 DOI: 10.1016/j.tcb.2022.07.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/11/2022] [Accepted: 07/13/2022] [Indexed: 12/22/2022]
Abstract
The MYC protooncogene functions as a universal amplifier of transcription through interaction with numerous factors and complexes that regulate almost every cellular process. However, a comprehensive model that explains MYC's actions and the interplay governing the complicated dynamics of components of the transcription and replication machinery is still lacking. Here, we review the potency of MYC as an oncogenic driver and how it regulates the broad spectrum of complexes (effectors and regulators). We propose a 'hand-over model' for differential partitioning and trafficking of unstructured MYC via a loose interaction network between various gene-regulatory complexes and factors. Additionally, the article discusses how unstructured-MYC energetically favors efficient modulation of the energy landscape of the transcription cycle.
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Affiliation(s)
- Subhendu K Das
- Gene Regulation Section, Laboratory of Pathology, Center for Cancer Research, National Cancer Institute (NCI), Bethesda, MD 20892-1500, USA
| | - Brian A Lewis
- Gene Regulation Section, Laboratory of Pathology, Center for Cancer Research, National Cancer Institute (NCI), Bethesda, MD 20892-1500, USA
| | - David Levens
- Gene Regulation Section, Laboratory of Pathology, Center for Cancer Research, National Cancer Institute (NCI), Bethesda, MD 20892-1500, USA.
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12
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The "Superoncogene" Myc at the Crossroad between Metabolism and Gene Expression in Glioblastoma Multiforme. Int J Mol Sci 2023; 24:ijms24044217. [PMID: 36835628 PMCID: PMC9966483 DOI: 10.3390/ijms24044217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/10/2023] [Accepted: 02/16/2023] [Indexed: 02/22/2023] Open
Abstract
The concept of the Myc (c-myc, n-myc, l-myc) oncogene as a canonical, DNA-bound transcription factor has consistently changed over the past few years. Indeed, Myc controls gene expression programs at multiple levels: directly binding chromatin and recruiting transcriptional coregulators; modulating the activity of RNA polymerases (RNAPs); and drawing chromatin topology. Therefore, it is evident that Myc deregulation in cancer is a dramatic event. Glioblastoma multiforme (GBM) is the most lethal, still incurable, brain cancer in adults, and it is characterized in most cases by Myc deregulation. Metabolic rewiring typically occurs in cancer cells, and GBM undergoes profound metabolic changes to supply increased energy demand. In nontransformed cells, Myc tightly controls metabolic pathways to maintain cellular homeostasis. Consistently, in Myc-overexpressing cancer cells, including GBM cells, these highly controlled metabolic routes are affected by enhanced Myc activity and show substantial alterations. On the other hand, deregulated cancer metabolism impacts Myc expression and function, placing Myc at the intersection between metabolic pathway activation and gene expression. In this review paper, we summarize the available information on GBM metabolism with a specific focus on the control of the Myc oncogene that, in turn, rules the activation of metabolic signals, ensuring GBM growth.
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13
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Bajpai S, Jin HR, Mucha B, Diehl JA. Ubiquitylation of unphosphorylated c-myc by novel E3 ligase SCF Fbxl8. Cancer Biol Ther 2022; 23:348-357. [PMID: 35438057 PMCID: PMC9037475 DOI: 10.1080/15384047.2022.2061279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/17/2022] [Accepted: 03/22/2022] [Indexed: 11/23/2022] Open
Abstract
Overexpression of c-myc via increased transcription or decreased protein degradation is common to many cancer etiologies. c-myc protein degradation is mediated by ubiquitin-dependent degradation, and this ubiquitylation is regulated by several E3 ligases. The primary regulator is Fbxw7, which binds to a phospho-degron within c-myc. Here, we identify a new E3 ligase for c-myc, Fbxl8 (F-box and Leucine Rich Repeat Protein 8), as an adaptor component of the SCF (Skp1-Cullin1-F-box protein) ubiquitin ligase complex, for selective c-myc degradation. SCFFbxl8 binds and ubiquitylates c-myc, independent of phosphorylation, revealing that it regulates a pool of c-myc distinct from SCFFbxw7. Loss of Fbxl8 increases c-myc protein levels, protein stability, and cell division, while overexpression of Fbxl8 reduces c-myc protein levels. Concurrent loss of Fbxl8 and Fbxw7 triggers a robust increase in c-myc protein levels consistent with targeting distinct pools of c-myc. This work highlights new mechanisms regulating c-myc degradation.
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Affiliation(s)
- Sagar Bajpai
- Department of Biochemistry and Molecular Biology, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, USA
| | - Hong Ri Jin
- Department of Biochemistry and Molecular Biology, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, USA
| | - Bartosz Mucha
- Department of Biochemistry and Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA
| | - J. Alan Diehl
- Department of Biochemistry and Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA
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14
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Osborne MJ, Volpon L, Memarpooryazdi M, Pillay S, Thambipillai A, Czarnota S, Culjkovic-Kraljacic B, Trahan C, Oeffinger M, Cowling VH, L B Borden K. Identification and characterization of the interaction between the methyl-7-guanosine cap maturation enzyme RNMT and the cap-binding protein eIF4E. J Mol Biol 2022; 434:167451. [PMID: 35026230 DOI: 10.1016/j.jmb.2022.167451] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 12/20/2022]
Abstract
The control of RNA metabolism is an important aspect of molecular biology with wide-ranging impacts on cells. Central to processing of coding RNAs is the addition of the methyl-7 guanosine (m7G) "cap" on their 5' end. The eukaryotic translation initiation factor eIF4E directly binds the m7G cap and through this interaction plays key roles in many steps of RNA metabolism including nuclear RNA export and translation. eIF4E also stimulates capping of many transcripts through its ability to drive the production of the enzyme RNMT which methylates the G-cap to form the mature m7G cap. Here, we found that eIF4E also physically associated with RNMT in human cells. Moreover, eIF4E directly interacted with RNMT in vitro. eIF4E is only the second protein reported to directly bind the methyltransferase domain of RNMT, the first being its co-factor RAM. We combined high-resolution NMR methods with biochemical studies to define the binding interfaces for the RNMT-eIF4E complex. Further, we found that eIF4E competes for RAM binding to RNMT and conversely, RNMT competes for binding of well-established eIF4E-binding partners such as the 4E-BPs. RNMT uses novel structural means to engage eIF4E. Finally, we observed that m7G cap-eIF4E-RNMT trimeric complexes form, and thus RNMT-eIF4E complexes may be employed so that eIF4E captures newly capped RNA. In all, we show for the first time that the cap-binding protein eIF4E directly binds to the cap-maturation enzyme RNMT.
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Affiliation(s)
- Michael J Osborne
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
| | - Laurent Volpon
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
| | - Mina Memarpooryazdi
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
| | - Subhadra Pillay
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada; Department of Biological Chemistry, Michigan Medicine, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Aksharh Thambipillai
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
| | - Sylwia Czarnota
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
| | - Biljana Culjkovic-Kraljacic
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
| | - Christian Trahan
- Department for Systems Biology, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Marlene Oeffinger
- Department for Systems Biology, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC H3T 1J4, Canada; Division of Experimental Medicine, McGill University, Montréal, QC, Canada
| | - Victoria H Cowling
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK, DD1 5EH
| | - Katherine L B Borden
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada.
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15
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Lourenco C, Resetca D, Redel C, Lin P, MacDonald AS, Ciaccio R, Kenney TMG, Wei Y, Andrews DW, Sunnerhagen M, Arrowsmith CH, Raught B, Penn LZ. MYC protein interactors in gene transcription and cancer. Nat Rev Cancer 2021; 21:579-591. [PMID: 34188192 DOI: 10.1038/s41568-021-00367-9] [Citation(s) in RCA: 145] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/04/2021] [Indexed: 02/07/2023]
Abstract
The transcription factor and oncoprotein MYC is a potent driver of many human cancers and can regulate numerous biological activities that contribute to tumorigenesis. How a single transcription factor can regulate such a diverse set of biological programmes is central to the understanding of MYC function in cancer. In this Perspective, we highlight how multiple proteins that interact with MYC enable MYC to regulate several central control points of gene transcription. These include promoter binding, epigenetic modifications, initiation, elongation and post-transcriptional processes. Evidence shows that a combination of multiple protein interactions enables MYC to function as a potent oncoprotein, working together in a 'coalition model', as presented here. Moreover, as MYC depends on its protein interactome for function, we discuss recent research that emphasizes an unprecedented opportunity to target protein interactors to directly impede MYC oncogenesis.
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Affiliation(s)
| | - Diana Resetca
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Cornelia Redel
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Peter Lin
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Alannah S MacDonald
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Roberto Ciaccio
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Tristan M G Kenney
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Yong Wei
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - David W Andrews
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Maria Sunnerhagen
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
| | - Cheryl H Arrowsmith
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Structural Genomics Consortium, Toronto, ON, Canada
| | - Brian Raught
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Linda Z Penn
- Princess Margaret Cancer Centre, Toronto, ON, Canada.
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
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16
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Ahmadi SE, Rahimi S, Zarandi B, Chegeni R, Safa M. MYC: a multipurpose oncogene with prognostic and therapeutic implications in blood malignancies. J Hematol Oncol 2021; 14:121. [PMID: 34372899 PMCID: PMC8351444 DOI: 10.1186/s13045-021-01111-4] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/12/2021] [Indexed: 12/17/2022] Open
Abstract
MYC oncogene is a transcription factor with a wide array of functions affecting cellular activities such as cell cycle, apoptosis, DNA damage response, and hematopoiesis. Due to the multi-functionality of MYC, its expression is regulated at multiple levels. Deregulation of this oncogene can give rise to a variety of cancers. In this review, MYC regulation and the mechanisms by which MYC adjusts cellular functions and its implication in hematologic malignancies are summarized. Further, we also discuss potential inhibitors of MYC that could be beneficial for treating hematologic malignancies.
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Affiliation(s)
- Seyed Esmaeil Ahmadi
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Samira Rahimi
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Bahman Zarandi
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Rouzbeh Chegeni
- Medical Laboratory Sciences Program, College of Health and Human Sciences, Northern Illinois University, DeKalb, IL, USA.
| | - Majid Safa
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran.
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran.
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17
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Borden K, Culjkovic-Kraljacic B, Cowling VH. To cap it all off, again: dynamic capping and recapping of coding and non-coding RNAs to control transcript fate and biological activity. Cell Cycle 2021; 20:1347-1360. [PMID: 34241559 PMCID: PMC8344758 DOI: 10.1080/15384101.2021.1930929] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The addition of the methyl-7-guanosine (m7G) “cap” on the 5' ends of coding and some non-coding RNAs is essential for their protein coding capacity and biochemical activity, respectively. It was previously considered that capping was a constitutive process that generates a complete cap on all transcripts at steady-state. However, development of new methodologies demonstrated that steady-state capping is a dynamic and regulatable feature of many coding and non-coding RNAs. Indeed, capping status of specific RNAs can flux during differentiation and development, thereby impacting on their protein-coding capacity and activity. Moreover, in some primary cancer specimens, capping can be elevated for transcripts encoding proteins involved in proliferation and survival corresponding to their increased protein levels. Overexpression of one of the capping enzymes (RNMT), the transcription factor MYC or the eukaryotic translation initiation factor eIF4E all led to increased levels of steady-state capping of selected transcripts. Additionally, transcripts can be decapped and recapped, allowing these to be sequestered until needed. This review provides a summary of the major advances in enzymatic and affinity-based approaches to quantify m7G capping. Further, we summarize the evidence for regulation of capping. Capping has emerged as a significant regulatory step in RNA metabolism which is poised to impact a myriad of biological processes.
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Affiliation(s)
- Klb Borden
- Department of Pathology and Cell Biology, Institute of Research in Immunology and Cancer, University of Montreal, Montreal, Canada
| | - B Culjkovic-Kraljacic
- Department of Pathology and Cell Biology, Institute of Research in Immunology and Cancer, University of Montreal, Montreal, Canada
| | - V H Cowling
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK, UK
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18
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Pellanda P, Dalsass M, Filipuzzi M, Loffreda A, Verrecchia A, Castillo Cano V, Thabussot H, Doni M, Morelli MJ, Soucek L, Kress T, Mazza D, Mapelli M, Beaulieu ME, Amati B, Sabò A. Integrated requirement of non-specific and sequence-specific DNA binding in Myc-driven transcription. EMBO J 2021; 40:e105464. [PMID: 33792944 DOI: 10.15252/embj.2020105464] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 02/15/2021] [Accepted: 02/24/2021] [Indexed: 12/17/2022] Open
Abstract
Eukaryotic transcription factors recognize specific DNA sequence motifs, but are also endowed with generic, non-specific DNA-binding activity. How these binding modes are integrated to determine select transcriptional outputs remains unresolved. We addressed this question by site-directed mutagenesis of the Myc transcription factor. Impairment of non-specific DNA backbone contacts caused pervasive loss of genome interactions and gene regulation, associated with increased intra-nuclear mobility of the Myc protein in murine cells. In contrast, a mutant lacking base-specific contacts retained DNA-binding and mobility profiles comparable to those of the wild-type protein, but failed to recognize its consensus binding motif (E-box) and could not activate Myc-target genes. Incidentally, this mutant gained weak affinity for an alternative motif, driving aberrant activation of different genes. Altogether, our data show that non-specific DNA binding is required to engage onto genomic regulatory regions; sequence recognition in turn contributes to transcriptional activation, acting at distinct levels: stabilization and positioning of Myc onto DNA, and-unexpectedly-promotion of its transcriptional activity. Hence, seemingly pervasive genome interaction profiles, as detected by ChIP-seq, actually encompass diverse DNA-binding modalities, driving defined, sequence-dependent transcriptional responses.
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Affiliation(s)
- Paola Pellanda
- European Institute of Oncology (IEO) - IRCCS, Milan, Italy.,Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia (IIT), Milan, Italy
| | - Mattia Dalsass
- European Institute of Oncology (IEO) - IRCCS, Milan, Italy
| | | | - Alessia Loffreda
- Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | | | - Virginia Castillo Cano
- Peptomyc S.L., Barcelona, Spain.,Vall d'Hebron Institute of Oncology (VHIO), Edifici Cellex, Barcelona, Spain
| | | | - Mirko Doni
- European Institute of Oncology (IEO) - IRCCS, Milan, Italy
| | - Marco J Morelli
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia (IIT), Milan, Italy
| | - Laura Soucek
- Peptomyc S.L., Barcelona, Spain.,Vall d'Hebron Institute of Oncology (VHIO), Edifici Cellex, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.,Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Theresia Kress
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia (IIT), Milan, Italy
| | - Davide Mazza
- Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Marina Mapelli
- European Institute of Oncology (IEO) - IRCCS, Milan, Italy
| | | | - Bruno Amati
- European Institute of Oncology (IEO) - IRCCS, Milan, Italy
| | - Arianna Sabò
- European Institute of Oncology (IEO) - IRCCS, Milan, Italy
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19
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Interplay of mRNA capping and transcription machineries. Biosci Rep 2021; 40:221784. [PMID: 31904821 PMCID: PMC6981093 DOI: 10.1042/bsr20192825] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 01/02/2020] [Accepted: 01/06/2020] [Indexed: 12/31/2022] Open
Abstract
Early stages of transcription from eukaryotic promoters include two principal events: the capping of newly synthesized mRNA and the transition of RNA polymerase II from the preinitiation complex to the productive elongation state. The capping checkpoint model implies that these events are tightly coupled, which is necessary for ensuring the proper capping of newly synthesized mRNA. Recent findings also show that the capping machinery has a wider effect on transcription and the entire gene expression process. The molecular basis of these phenomena is discussed.
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20
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Culjkovic-Kraljacic B, Skrabanek L, Revuelta MV, Gasiorek J, Cowling VH, Cerchietti L, Borden KLB. The eukaryotic translation initiation factor eIF4E elevates steady-state m 7G capping of coding and noncoding transcripts. Proc Natl Acad Sci U S A 2020; 117:26773-26783. [PMID: 33055213 PMCID: PMC7604501 DOI: 10.1073/pnas.2002360117] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Methyl-7-guanosine (m7G) "capping" of coding and some noncoding RNAs is critical for their maturation and subsequent activity. Here, we discovered that eukaryotic translation initiation factor 4E (eIF4E), itself a cap-binding protein, drives the expression of the capping machinery and increased capping efficiency of ∼100 coding and noncoding RNAs. To quantify this, we developed enzymatic (cap quantification; CapQ) and quantitative cap immunoprecipitation (CapIP) methods. The CapQ method has the further advantage that it captures information about capping status independent of the type of 5' cap, i.e., it is not restricted to informing on m7G caps. These methodological advances led to unanticipated revelations: 1) Many RNA populations are inefficiently capped at steady state (∼30 to 50%), and eIF4E overexpression increased this to ∼60 to 100%, depending on the RNA; 2) eIF4E physically associates with noncoding RNAs in the nucleus; and 3) approximately half of eIF4E-capping targets identified are noncoding RNAs. eIF4E's association with noncoding RNAs strongly positions it to act beyond translation. Coding and noncoding capping targets have activities that influence survival, cell morphology, and cell-to-cell interaction. Given that RNA export and translation machineries typically utilize capped RNA substrates, capping regulation provides means to titrate the protein-coding capacity of the transcriptome and, for noncoding RNAs, to regulate their activities. We also discovered a cap sensitivity element (CapSE) which conferred eIF4E-dependent capping sensitivity. Finally, we observed elevated capping for specific RNAs in high-eIF4E leukemia specimens, supporting a role for cap dysregulation in malignancy. In all, levels of capping RNAs can be regulated by eIF4E.
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Affiliation(s)
- Biljana Culjkovic-Kraljacic
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Lucy Skrabanek
- Applied Bioinformatics Core, Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065
| | - Maria V Revuelta
- Division of Hematology & Medical Oncology, Department of Medicine, Weill Cornell Medicine, New York, NY 10065
| | - Jadwiga Gasiorek
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Victoria H Cowling
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Leandro Cerchietti
- Division of Hematology & Medical Oncology, Department of Medicine, Weill Cornell Medicine, New York, NY 10065
| | - Katherine L B Borden
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Montréal, QC H3T 1J4, Canada;
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Marchingo JM, Sinclair LV, Howden AJ, Cantrell DA. Quantitative analysis of how Myc controls T cell proteomes and metabolic pathways during T cell activation. eLife 2020; 9:53725. [PMID: 32022686 PMCID: PMC7056270 DOI: 10.7554/elife.53725] [Citation(s) in RCA: 110] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/04/2020] [Indexed: 12/12/2022] Open
Abstract
T cell expansion and differentiation are critically dependent on the transcription factor c-Myc (Myc). Herein we use quantitative mass-spectrometry to reveal how Myc controls antigen receptor driven cell growth and proteome restructuring in murine T cells. Analysis of copy numbers per cell of >7000 proteins provides new understanding of the selective role of Myc in controlling the protein machinery that govern T cell fate. The data identify both Myc dependent and independent metabolic processes in immune activated T cells. We uncover that a primary function of Myc is to control expression of multiple amino acid transporters and that loss of a single Myc-controlled amino acid transporter effectively phenocopies the impact of Myc deletion. This study provides a comprehensive map of how Myc selectively shapes T cell phenotypes, revealing that Myc induction of amino acid transport is pivotal for subsequent bioenergetic and biosynthetic programs and licences T cell receptor driven proteome reprogramming.
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Affiliation(s)
- Julia M Marchingo
- Cell Signalling and Immunology Division, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Linda V Sinclair
- Cell Signalling and Immunology Division, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Andrew Jm Howden
- Cell Signalling and Immunology Division, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Doreen A Cantrell
- Cell Signalling and Immunology Division, School of Life Sciences, University of Dundee, Dundee, United Kingdom
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22
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Galloway A, Atrih A, Grzela R, Darzynkiewicz E, Ferguson MAJ, Cowling VH. CAP-MAP: cap analysis protocol with minimal analyte processing, a rapid and sensitive approach to analysing mRNA cap structures. Open Biol 2020; 10:190306. [PMID: 32097574 PMCID: PMC7058934 DOI: 10.1098/rsob.190306] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 01/30/2020] [Indexed: 01/06/2023] Open
Abstract
Eukaryotic messenger RNA (mRNA) is modified by the addition of an inverted guanosine cap to the 5' triphosphate. The cap guanosine and initial transcribed nucleotides are further methylated by a series of cap methyltransferases to generate the mature cap structures which protect RNA from degradation and recruit proteins involved in RNA processing and translation. Research demonstrating that the cap methyltransferases are regulated has generated interest in determining the methylation status of the mRNA cap structures present in cells. Here, we present CAP-MAP: cap analysis protocol with minimal analyte processing, a rapid and sensitive method for detecting cap structures present in mRNA isolated from tissues or cultured cells.
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Affiliation(s)
- Alison Galloway
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Abdelmadjid Atrih
- FingerPrints Proteomics Facility, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Renata Grzela
- Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
| | - Edward Darzynkiewicz
- Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-097 Warsaw, Poland
| | - Michael A. J. Ferguson
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Victoria H. Cowling
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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Tsuda-Sakurai K, Kimura M, Miura M. Diphthamide modification of eEF2 is required for gut tumor-like hyperplasia induced by oncogenic Ras. Genes Cells 2019; 25:76-85. [PMID: 31828897 DOI: 10.1111/gtc.12742] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 10/27/2019] [Accepted: 11/20/2019] [Indexed: 01/16/2023]
Abstract
Eukaryotic elongation factor 2 (eEF2) undergoes a unique post-translational modification called diphthamidation. Although eEF2 diphthamidation is highly conserved, its pathophysiological function is still largely unknown. To elucidate the function of diphthamidation in tumor, we examined the involvement of diphthamidation pathway enzyme Dph5 in tumor progression in Drosophila adult gut. Expression of oncogenic RasV12 in gut intestinal stem cells (ISCs) and enteroblasts (EBs) causes hypertrophy and disruption of gut epithelia, and shortened life span. Knockdown of Dph5 ameliorated these pathogenic phenotypes. Dph5 is required for gross translation activation and high dMyc protein level in RasV12 tumor-like hyperplasia. Transcriptome analysis revealed that Dph5 is involved in the regulation of ribosome biogenesis genes. These results suggest that diphthamidation is required for translation activation partly through the regulation of ribosome biogenesis in Ras-induced tumor-like hyperplasia model in Drosophila gut.
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Affiliation(s)
- Kayoko Tsuda-Sakurai
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Masaki Kimura
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Masayuki Miura
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
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Filip D, Mraz M. The role of MYC in the transformation and aggressiveness of ‘indolent’ B-cell malignancies. Leuk Lymphoma 2019; 61:510-524. [DOI: 10.1080/10428194.2019.1675877] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Daniel Filip
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- Department of Internal Medicine, Haematology and Oncology, University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Marek Mraz
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- Department of Internal Medicine, Haematology and Oncology, University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic
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Shao YY, Li YS, Hsu HW, Lin H, Wang HY, Wo RR, Cheng AL, Hsu CH. Potent Activity of Composite Cyclin Dependent Kinase Inhibition against Hepatocellular Carcinoma. Cancers (Basel) 2019; 11:cancers11101433. [PMID: 31561409 PMCID: PMC6827105 DOI: 10.3390/cancers11101433] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 09/19/2019] [Indexed: 12/18/2022] Open
Abstract
Alterations in cell cycle regulators are common in hepatocellular carcinoma (HCC). We tested the efficacy of composite inhibition of CDKs 1, 2, 5, and 9 through dinaciclib on HCC. In vitro, dinaciclib exhibited potent antiproliferative activities in HCC cell lines regardless of Rb or c-myc expression levels. Dinaciclib significantly downregulated the phosphorylation of Rb (target of CDKs 1 and 2), ataxia telangiectasia mutated kinase (target of CDK5), and RNA polymerase II (target of CDK9) in the HCC cells. In xenograft studies, mice receiving dinaciclib tolerated the treatment well without significant body weight changes and exhibited a significantly slower tumor growth rate than the mice receiving vehicles. RNA interference (RNAi) of CDKs 1 and 9 was more effective in inhibiting the cell proliferation of HCC cells than RNAi of CDKs 2 and 5. Overexpression of CDK9 significantly reduced the efficacy of dinaciclib in HCC cells, but overexpression of CDK1 did not. In conclusion, composite inhibition of CDKs 1, 2, 5, and 9 through dinaciclib exhibited potent in vitro and in vivo activity against HCC. CDK9 inhibition might be the crucial mechanism.
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Affiliation(s)
- Yu-Yun Shao
- Graduate Institute of Oncology, National Taiwan University College of Medicine, Taipei 10051, Taiwan.
- National Taiwan University Cancer Center, National Taiwan University College of Medicine, Taipei 10051, Taiwan.
- Department of Oncology, National Taiwan University Hospital, Taipei 10002, Taiwan.
| | - Yong-Shi Li
- Department of Oncology, National Taiwan University Hospital, Taipei 10002, Taiwan.
| | - Hung-Wei Hsu
- Department of Oncology, National Taiwan University Hospital, Taipei 10002, Taiwan.
| | - Hang Lin
- Department of Oncology, National Taiwan University Hospital, Taipei 10002, Taiwan.
| | - Han-Yu Wang
- Department of Oncology, National Taiwan University Hospital, Taipei 10002, Taiwan.
| | - Rita Robin Wo
- Department of Oncology, National Taiwan University Hospital, Taipei 10002, Taiwan.
| | - Ann-Lii Cheng
- Graduate Institute of Oncology, National Taiwan University College of Medicine, Taipei 10051, Taiwan.
- National Taiwan University Cancer Center, National Taiwan University College of Medicine, Taipei 10051, Taiwan.
- Department of Oncology, National Taiwan University Hospital, Taipei 10002, Taiwan.
- Department of Internal Medicine, National Taiwan University College of Medicine, Taipei 10051, Taiwan.
| | - Chih-Hung Hsu
- Graduate Institute of Oncology, National Taiwan University College of Medicine, Taipei 10051, Taiwan.
- National Taiwan University Cancer Center, National Taiwan University College of Medicine, Taipei 10051, Taiwan.
- Department of Oncology, National Taiwan University Hospital, Taipei 10002, Taiwan.
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Abdel-Azim H, Sun W, Wu L. Strategies to generate functionally normal neutrophils to reduce infection and infection-related mortality in cancer chemotherapy. Pharmacol Ther 2019; 204:107403. [PMID: 31470030 DOI: 10.1016/j.pharmthera.2019.107403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 08/19/2019] [Indexed: 02/08/2023]
Abstract
Neutrophils form an essential part of innate immunity against infection. Cancer chemotherapy-induced neutropenia (CCIN) is a condition in which the number of neutrophils in a patient's bloodstream is decreased, leading to increased susceptibility to infection. Granulocyte colony-stimulating factor (GCSF) has been the only approved treatment for CCIN over two decades. To date, CCIN-related infection and mortality remain a significant concern, as neutrophils generated in response to administered GCSF are functionally immature and cannot effectively fight infection. This review summarizes the molecular regulatory mechanisms of neutrophil granulocytic differentiation and innate immunity development, dissects the biology of GCSF in myeloid expansion, highlights the shortcomings of GCSF in CCIN treatment, updates the recent advance of a selective retinoid agonist that promotes neutrophil granulocytic differentiation, and evaluates the benefits of developing GCSF biosimilars to increase access to GCSF biologics versus seeking a new mode to fundamentally advance GCSF therapy for treatment of CCIN.
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Affiliation(s)
- Hisham Abdel-Azim
- Pediatric Hematology-Oncology, Blood and Marrow Transplantation, Children's Hospital Los Angeles Saban Research Institute, University of Southern California Keck School of Medicine, 4650 Sunset Blvd, Los Angeles, CA 90027, USA
| | - Weili Sun
- Pediatric Hematology-Oncology, City of Hope National Medical Center, 1500 E. Duarte road, Duarte, CA 91010, USA
| | - Lingtao Wu
- Research and Development, Therapeutic Approaches, 2712 San Gabriel Boulevard, Rosemead, CA 91770, USA.
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Wang XN, Su XX, Cheng SQ, Sun ZY, Huang ZS, Ou TM. MYC modulators in cancer: a patent review. Expert Opin Ther Pat 2019; 29:353-367. [PMID: 31068032 DOI: 10.1080/13543776.2019.1612878] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
INTRODUCTION The important role of MYC in tumorigenesis makes it particularly important to design MYC modulators. Over the past decade, researchers have raised a number of strategies for designing MYC modulators, some of which are already in clinical trials. This paper aims to review the patents of MYC modulators. AREAS COVERED The important biological relevance of c-MYC and the regulation pathways related to c-MYC are briefly introduced. Base on that, the MYC modulators reported in published patents and references primarily for cancer treatment are outlined, highlighting the structures and biological activities. EXPERT OPINION There has been a growing awareness of finding and designing MYC modulators as novel anticancer drugs over recent years. Patents involving the discovery, synthesis, and application of MYC modulators are particularly important for further development in this field. Although finding direct MYC inhibitors or binders is challenging, MYC cannot be simply defined as an undruggable target. There is still substantial evidence proving the concept that MYC modulators can benefit to the treatment of both human hematological malignancies and solid tumors. More efforts should be taken to improve the activity and specificity of MYC modulators.
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Affiliation(s)
- Xiao-Na Wang
- a School of Pharmaceutical Sciences , Sun Yat-Sen University , Guangzhou , Guangdong , China
| | - Xiao-Xuan Su
- a School of Pharmaceutical Sciences , Sun Yat-Sen University , Guangzhou , Guangdong , China
| | - Sui-Qi Cheng
- a School of Pharmaceutical Sciences , Sun Yat-Sen University , Guangzhou , Guangdong , China
| | - Zhi-Yin Sun
- a School of Pharmaceutical Sciences , Sun Yat-Sen University , Guangzhou , Guangdong , China
| | - Zhi-Shu Huang
- a School of Pharmaceutical Sciences , Sun Yat-Sen University , Guangzhou , Guangdong , China
| | - Tian-Miao Ou
- a School of Pharmaceutical Sciences , Sun Yat-Sen University , Guangzhou , Guangdong , China
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Dunn S, Lombardi O, Lukoszek R, Cowling VH. Oncogenic PIK3CA mutations increase dependency on the mRNA cap methyltransferase, RNMT, in breast cancer cells. Open Biol 2019; 9:190052. [PMID: 30991934 PMCID: PMC6501644 DOI: 10.1098/rsob.190052] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 03/19/2019] [Indexed: 01/16/2023] Open
Abstract
Basic mechanisms in gene expression are currently being investigated as targets in cancer therapeutics. One such fundamental process is the addition of the cap to pre-mRNA, which recruits mediators of mRNA processing and translation initiation. Maturation of the cap involves mRNA cap guanosine N-7 methylation, catalysed by RNMT (RNA guanine-7 methyltransferase). In a panel of breast cancer cell lines, we investigated whether all are equivalently dependent on RNMT for proliferation. When cellular RNMT activity was experimentally reduced by 50%, the proliferation rate of non-transformed mammary epithelial cells was unchanged, whereas a subset of breast cancer cell lines exhibited reduced proliferation and increased apoptosis. Most of the cell lines which exhibited enhanced dependency on RNMT harboured oncogenic mutations in PIK3CA, which encodes the p110α subunit of PI3Kα. Conversely, all cell lines insensitive to RNMT depletion expressed wild-type PIK3CA. Expression of oncogenic PIK3CA mutants, which increase PI3K p110α activity, was sufficient to increase dependency on RNMT. Conversely, inhibition of PI3Kα reversed dependency on RNMT, suggesting that PI3Kα signalling is required. Collectively, these findings provide evidence to support RNMT as a therapeutic target in breast cancer and suggest that therapies targeting RNMT would be most valuable in a PIK3CA mutant background.
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Affiliation(s)
| | | | | | - Victoria H. Cowling
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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29
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García-Gutiérrez L, Delgado MD, León J. MYC Oncogene Contributions to Release of Cell Cycle Brakes. Genes (Basel) 2019; 10:E244. [PMID: 30909496 PMCID: PMC6470592 DOI: 10.3390/genes10030244] [Citation(s) in RCA: 113] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 03/16/2019] [Accepted: 03/18/2019] [Indexed: 12/12/2022] Open
Abstract
Promotion of the cell cycle is a major oncogenic mechanism of the oncogene c-MYC (MYC). MYC promotes the cell cycle by not only activating or inducing cyclins and CDKs but also through the downregulation or the impairment of the activity of a set of proteins that act as cell-cycle brakes. This review is focused on the role of MYC as a cell-cycle brake releaser i.e., how MYC stimulates the cell cycle mainly through the functional inactivation of cell cycle inhibitors. MYC antagonizes the activities and/or the expression levels of p15, ARF, p21, and p27. The mechanism involved differs for each protein. p15 (encoded by CDKN2B) and p21 (CDKN1A) are repressed by MYC at the transcriptional level. In contrast, MYC activates ARF, which contributes to the apoptosis induced by high MYC levels. At least in some cells types, MYC inhibits the transcription of the p27 gene (CDKN1B) but also enhances p27's degradation through the upregulation of components of ubiquitin ligases complexes. The effect of MYC on cell-cycle brakes also opens the possibility of antitumoral therapies based on synthetic lethal interactions involving MYC and CDKs, for which a series of inhibitors are being developed and tested in clinical trials.
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Affiliation(s)
- Lucía García-Gutiérrez
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC) CSIC-Universidad de Cantabria and Department of Biología Molecular, Universidad de Cantabria, 39011 Santander, Spain.
- Current address: Systems Biology Ireland, University College Dublin, Belfield, Dublin 4, Ireland.
| | - María Dolores Delgado
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC) CSIC-Universidad de Cantabria and Department of Biología Molecular, Universidad de Cantabria, 39011 Santander, Spain.
| | - Javier León
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC) CSIC-Universidad de Cantabria and Department of Biología Molecular, Universidad de Cantabria, 39011 Santander, Spain.
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Galloway A, Cowling VH. mRNA cap regulation in mammalian cell function and fate. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2019; 1862:270-279. [PMID: 30312682 PMCID: PMC6414751 DOI: 10.1016/j.bbagrm.2018.09.011] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 09/13/2018] [Accepted: 09/30/2018] [Indexed: 12/17/2022]
Abstract
In this review we explore the regulation of mRNA cap formation and its impact on mammalian cells. The mRNA cap is a highly methylated modification of the 5' end of RNA pol II-transcribed RNA. It protects RNA from degradation, recruits complexes involved in RNA processing, export and translation initiation, and marks cellular mRNA as "self" to avoid recognition by the innate immune system. The mRNA cap can be viewed as a unique mark which selects RNA pol II transcripts for specific processing and translation. Over recent years, examples of regulation of mRNA cap formation have emerged, induced by oncogenes, developmental pathways and during the cell cycle. These signalling pathways regulate the rate and extent of mRNA cap formation, resulting in changes in gene expression, cell physiology and cell function.
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Affiliation(s)
- Alison Galloway
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Victoria H Cowling
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
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Networks of mRNA Processing and Alternative Splicing Regulation in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1157:1-27. [PMID: 31342435 DOI: 10.1007/978-3-030-19966-1_1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
mRNA processing events introduce an intricate layer of complexity into gene expression processes, supporting a tremendous level of diversification of the genome's coding and regulatory potential, particularly in vertebrate species. The recent development of massive parallel sequencing methods and their adaptation to the identification and quantification of different RNA species and the dynamics of mRNA metabolism and processing has generated an unprecedented view over the regulatory networks that are established at this level, which contribute to sustain developmental, tissue specific or disease specific gene expression programs. In this chapter, we provide an overview of the recent evolution of transcriptome profiling methods and the surprising insights that have emerged in recent years regarding distinct mRNA processing events - from the 5' end to the 3' end of the molecule.
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Felgenhauer J, Tomino L, Selich-Anderson J, Bopp E, Shah N. Dual BRD4 and AURKA Inhibition Is Synergistic against MYCN-Amplified and Nonamplified Neuroblastoma. Neoplasia 2018; 20:965-974. [PMID: 30153557 PMCID: PMC6111011 DOI: 10.1016/j.neo.2018.08.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 07/02/2018] [Accepted: 08/02/2018] [Indexed: 11/29/2022] Open
Abstract
A majority of cases of high-risk neuroblastoma, an embryonal childhood cancer, are driven by MYC or MYCN-driven oncogenic signaling. While considered to be directly “undruggable” therapeutically, MYC and MYCN can be repressed transcriptionally by inhibition of Bromodomain-containing protein 4 (BRD4) or destabilized posttranslationally by inhibition of Aurora Kinase A (AURKA). Preclinical and early-phase clinical studies of BRD4 and AURKA inhibitors, however, show limited efficacy against neuroblastoma when used alone. We report our studies on the concomitant use of the BRD4 inhibitor I-BET151 and AURKA inhibitor alisertib. We show that, in vitro, the drugs act synergistically to inhibit viability in four models of high-risk neuroblastoma. We demonstrate that this synergy is driven, in part, by the ability of I-BET151 to mitigate reflexive upregulation of AURKA, MYC, and MYCN in response to AURKA inhibition. We then demonstrate that I-BET151 and alisertib are effective in prolonging survival in four xenograft neuroblastoma models in vivo, and this efficacy is augmented by the addition of the antitubule chemotherapeutic vincristine. These data suggest that epigenetic and posttranslational inhibition of MYC/MYCN-driven pathways may have significant clinical efficacy against neuroblastoma.
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Affiliation(s)
- Joshua Felgenhauer
- Nationwide Children's Hospital, Center for Childhood Cancer and Blood Disorders, 700 Children's Drive, Columbus, OH, 43205
| | - Laura Tomino
- Nationwide Children's Hospital, Center for Childhood Cancer and Blood Disorders, 700 Children's Drive, Columbus, OH, 43205
| | - Julia Selich-Anderson
- Nationwide Children's Hospital, Center for Childhood Cancer and Blood Disorders, 700 Children's Drive, Columbus, OH, 43205
| | - Emily Bopp
- The Ohio State University, College of Arts and Sciences, 186 University Hall, Columbus, OH, 43210
| | - Nilay Shah
- Nationwide Children's Hospital, Center for Childhood Cancer and Blood Disorders, 700 Children's Drive, Columbus, OH, 43205; The Ohio State University, College of Medicine, Department of Pediatrics, 370 W 9th Ave, Columbus, OH 43210.
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Pérez-Olivares M, Trento A, Rodriguez-Acebes S, González-Acosta D, Fernández-Antorán D, Román-García S, Martinez D, López-Briones T, Torroja C, Carrasco YR, Méndez J, Moreno de Alborán I. Functional interplay between c-Myc and Max in B lymphocyte differentiation. EMBO Rep 2018; 19:embr.201845770. [PMID: 30126925 DOI: 10.15252/embr.201845770] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 07/26/2018] [Accepted: 07/30/2018] [Indexed: 12/11/2022] Open
Abstract
The Myc family of oncogenic transcription factors regulates myriad cellular functions. Myc proteins contain a basic region/helix-loop-helix/leucine zipper domain that mediates DNA binding and heterodimerization with its partner Max. Among the Myc proteins, c-Myc is the most widely expressed and relevant in primary B lymphocytes. There is evidence suggesting that c-Myc can perform some of its functions in the absence of Max in different cellular contexts. However, the functional in vivo interplay between c-Myc and Max during B lymphocyte differentiation is not well understood. Using in vivo and ex vivo models, we show that while c-Myc requires Max in primary B lymphocytes, several key biological processes, such as cell differentiation and DNA replication, can initially progress without the formation of c-Myc/Max heterodimers. We also describe that B lymphocytes lacking Myc, Max, or both show upregulation of signaling pathways associated with the B-cell receptor. These data suggest that c-Myc/Max heterodimers are not essential for the initiation of a subset of important biological processes in B lymphocytes, but are required for fine-tuning the initial response after activation.
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Affiliation(s)
- Mercedes Pérez-Olivares
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)-CSIC, Madrid, Spain
| | - Alfonsina Trento
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)-CSIC, Madrid, Spain
| | | | | | - David Fernández-Antorán
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)-CSIC, Madrid, Spain
| | - Sara Román-García
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)-CSIC, Madrid, Spain
| | - Dolores Martinez
- Centro Nacional de Investigaciones Oncológicas-CNIO, Madrid, Spain
| | | | - Carlos Torroja
- Centro Nacional de Investigaciones Cardiovasculares-CNIC Carlos III, Madrid, Spain
| | - Yolanda R Carrasco
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)-CSIC, Madrid, Spain
| | - Juan Méndez
- Centro Nacional de Investigaciones Oncológicas-CNIO, Madrid, Spain
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Wolpaw AJ, Dang CV. MYC-induced metabolic stress and tumorigenesis. Biochim Biophys Acta Rev Cancer 2018; 1870:43-50. [PMID: 29791870 DOI: 10.1016/j.bbcan.2018.05.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 12/25/2022]
Abstract
The MYC oncogene is commonly altered across human cancers. Distinct from the normal MYC proto-oncogene, which is under tight transcriptional, translational, and post-translational control, deregulated oncogenic MYC drives imbalanced, non-linear amplification of transcription that results in oncogenic 'stress.' The term 'stress' had been a euphemism for our lack of mechanistic understanding, but synthesis of many studies over the past decade provides a more coherent picture of oncogenic MYC driving metastable cellular states, particularly altered metabolism, that activate and depend on cellular stress response pathways to allow for continued growth and survival. Both deregulated metabolism and these stress response pathways represent vulnerabilities that can be exploited therapeutically.
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Affiliation(s)
- Adam J Wolpaw
- Divisions of Hematology and Oncology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; The Wistar Institute, Philadelphia, PA 19104, USA
| | - Chi V Dang
- The Wistar Institute, Philadelphia, PA 19104, USA; Ludwig Institute for Cancer Research, New York, NY 10017, USA.
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35
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Schaub FX, Dhankani V, Berger AC, Trivedi M, Richardson AB, Shaw R, Zhao W, Zhang X, Ventura A, Liu Y, Ayer DE, Hurlin PJ, Cherniack AD, Eisenman RN, Bernard B, Grandori C. Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas. Cell Syst 2018; 6:282-300.e2. [PMID: 29596783 PMCID: PMC5892207 DOI: 10.1016/j.cels.2018.03.003] [Citation(s) in RCA: 233] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 02/06/2018] [Accepted: 03/02/2018] [Indexed: 12/19/2022]
Abstract
Although the MYC oncogene has been implicated in cancer, a systematic assessment of alterations of MYC, related transcription factors, and co-regulatory proteins, forming the proximal MYC network (PMN), across human cancers is lacking. Using computational approaches, we define genomic and proteomic features associated with MYC and the PMN across the 33 cancers of The Cancer Genome Atlas. Pan-cancer, 28% of all samples had at least one of the MYC paralogs amplified. In contrast, the MYC antagonists MGA and MNT were the most frequently mutated or deleted members, proposing a role as tumor suppressors. MYC alterations were mutually exclusive with PIK3CA, PTEN, APC, or BRAF alterations, suggesting that MYC is a distinct oncogenic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such as immune response and growth factor signaling; chromatin, translation, and DNA replication/repair were conserved pan-cancer. This analysis reveals insights into MYC biology and is a reference for biomarkers and therapeutics for cancers with alterations of MYC or the PMN.
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Affiliation(s)
- Franz X Schaub
- Cure First, Seattle, WA, USA; SEngine Precision Medicine, Seattle, WA, USA
| | | | - Ashton C Berger
- The Eli and Edythe L. Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, MA, USA
| | | | | | - Reid Shaw
- SEngine Precision Medicine, Seattle, WA, USA
| | - Wei Zhao
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Xiaoyang Zhang
- Dana-Farber Cancer Institute, the Broad Institute of Harvard and MIT, and Harvard Medical School, Boston, MA, USA
| | - Andrea Ventura
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Yuexin Liu
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Donald E Ayer
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
| | - Peter J Hurlin
- Shriners Hospitals for Children Research Center, Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Knight Cancer Institute, Oregon Health & Science University, Portland, OR, USA
| | - Andrew D Cherniack
- Dana-Farber Cancer Institute, the Broad Institute of Harvard and MIT, and Harvard Medical School, Boston, MA, USA
| | - Robert N Eisenman
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Brady Bernard
- Institute for Systems Biology, Seattle, WA, USA; Providence Health and Services, Portland, OR, USA.
| | - Carla Grandori
- Cure First, Seattle, WA, USA; SEngine Precision Medicine, Seattle, WA, USA.
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Lombardi O, Varshney D, Phillips NM, Cowling VH. c-Myc deregulation induces mRNA capping enzyme dependency. Oncotarget 2018; 7:82273-82288. [PMID: 27756891 PMCID: PMC5347691 DOI: 10.18632/oncotarget.12701] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 10/10/2016] [Indexed: 01/24/2023] Open
Abstract
c-Myc is a potent driver of many human cancers. Since strategies for directly targeting c-Myc protein have had limited success, upstream regulators and downstream effectors of c-Myc are being investigated as alternatives for therapeutic intervention. c-Myc regulates transcription and formation of the mRNA cap, which is important for transcript maturation and translation. However, the direct mechanism by which c-Myc upregulates mRNA capping is unclear. mRNA cap formation initiates with the linkage of inverted guanosine via a triphosphate bridge to the first transcribed nucleotide, catalysed by mRNA capping enzyme (CE/RNGTT). Here we report that c-Myc increases the recruitment of catalytically active CE to RNA polymerase II and to its target genes. c-Myc-induced target gene expression, cell proliferation and cell transformation is highly dependent on CE, but only when c-Myc is deregulated. Cells retaining normal control of c-Myc expression are insensitive to repression of CE. c-Myc expression is also dependent on CE. Therefore, inhibiting CE provides an attractive route for selective therapeutic targeting of cancer cells which have acquired deregulated c-Myc.
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Affiliation(s)
- Olivia Lombardi
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Dhaval Varshney
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Nicola M Phillips
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.,School of Science and the Environment, Manchester Metropolitan University, Manchester, M15 6BH, UK
| | - Victoria H Cowling
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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Büchel G, Carstensen A, Mak KY, Roeschert I, Leen E, Sumara O, Hofstetter J, Herold S, Kalb J, Baluapuri A, Poon E, Kwok C, Chesler L, Maric HM, Rickman DS, Wolf E, Bayliss R, Walz S, Eilers M. Association with Aurora-A Controls N-MYC-Dependent Promoter Escape and Pause Release of RNA Polymerase II during the Cell Cycle. Cell Rep 2017; 21:3483-3497. [PMID: 29262328 PMCID: PMC5746598 DOI: 10.1016/j.celrep.2017.11.090] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 10/12/2017] [Accepted: 11/27/2017] [Indexed: 12/17/2022] Open
Abstract
MYC proteins bind globally to active promoters and promote transcriptional elongation by RNA polymerase II (Pol II). To identify effector proteins that mediate this function, we performed mass spectrometry on N-MYC complexes in neuroblastoma cells. The analysis shows that N-MYC forms complexes with TFIIIC, TOP2A, and RAD21, a subunit of cohesin. N-MYC and TFIIIC bind to overlapping sites in thousands of Pol II promoters and intergenic regions. TFIIIC promotes association of RAD21 with N-MYC target sites and is required for N-MYC-dependent promoter escape and pause release of Pol II. Aurora-A competes with binding of TFIIIC and RAD21 to N-MYC in vitro and antagonizes association of TOP2A, TFIIIC, and RAD21 with N-MYC during S phase, blocking N-MYC-dependent release of Pol II from the promoter. Inhibition of Aurora-A in S phase restores RAD21 and TFIIIC binding to chromatin and partially restores N-MYC-dependent transcriptional elongation. We propose that complex formation with Aurora-A controls N-MYC function during the cell cycle.
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Affiliation(s)
- Gabriele Büchel
- Theodor Boveri Institute and Comprehensive Cancer Center Mainfranken, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Anne Carstensen
- Theodor Boveri Institute and Comprehensive Cancer Center Mainfranken, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Ka-Yan Mak
- Theodor Boveri Institute and Comprehensive Cancer Center Mainfranken, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Isabelle Roeschert
- Theodor Boveri Institute and Comprehensive Cancer Center Mainfranken, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Eoin Leen
- Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK; University of Leicester, Leicester LE1 9HN, UK
| | - Olga Sumara
- Theodor Boveri Institute and Comprehensive Cancer Center Mainfranken, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Julia Hofstetter
- Cancer Systems Biology Group, Biochemistry and Molecular Biology, University of Würzburg, 97074 Würzburg, Germany
| | - Steffi Herold
- Theodor Boveri Institute and Comprehensive Cancer Center Mainfranken, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Jacqueline Kalb
- Theodor Boveri Institute and Comprehensive Cancer Center Mainfranken, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Apoorva Baluapuri
- Cancer Systems Biology Group, Biochemistry and Molecular Biology, University of Würzburg, 97074 Würzburg, Germany
| | - Evon Poon
- Division of Clinical Studies and Cancer Therapeutics, The Institute of Cancer Research, The Royal Marsden NHS Trust, 15 Cotswold Rd., Belmont, Sutton, Surrey SM2 5NG, UK
| | - Colin Kwok
- Division of Clinical Studies and Cancer Therapeutics, The Institute of Cancer Research, The Royal Marsden NHS Trust, 15 Cotswold Rd., Belmont, Sutton, Surrey SM2 5NG, UK
| | - Louis Chesler
- Division of Clinical Studies and Cancer Therapeutics, The Institute of Cancer Research, The Royal Marsden NHS Trust, 15 Cotswold Rd., Belmont, Sutton, Surrey SM2 5NG, UK
| | - Hans Michael Maric
- Department of Drug Design and Pharmacology, Center for Biopharmaceuticals, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - David S Rickman
- Weill Cornell Medicine, Sandra and Edward Meyer Cancer Center, 413 E. 69(th) Street, New York, NY 10021, USA
| | - Elmar Wolf
- Cancer Systems Biology Group, Biochemistry and Molecular Biology, University of Würzburg, 97074 Würzburg, Germany
| | - Richard Bayliss
- Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK; University of Leicester, Leicester LE1 9HN, UK
| | - Susanne Walz
- Comprehensive Cancer Center Mainfranken, Core Unit Bioinformatics, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Martin Eilers
- Theodor Boveri Institute and Comprehensive Cancer Center Mainfranken, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
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Inesta‐Vaquera F, Cowling VH. Regulation and function of CMTR1-dependent mRNA cap methylation. WILEY INTERDISCIPLINARY REVIEWS. RNA 2017; 8:e1450. [PMID: 28971629 PMCID: PMC7169794 DOI: 10.1002/wrna.1450] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 08/10/2017] [Accepted: 08/17/2017] [Indexed: 12/24/2022]
Abstract
mRNA is modified co-transcriptionally at the 5' end by the addition of an inverted guanosine cap structure which can be methylated at several positions. The mRNA cap recruits proteins involved in gene expression and identifies the transcript as being cellular or 'self' in the innate immune response. Methylation of the first transcribed nucleotide on the ribose 2'-O position is a prevalent cap modification which has roles in splicing, translation and provides protection against the innate immune response. In this review, we discuss the regulation and function of CMTR1, the first transcribed nucleotide ribose 2'-O methyltransferase, and the molecular interactions which mediate methylated 2'-O ribose function. WIREs RNA 2017, 8:e1450. doi: 10.1002/wrna.1450 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
| | - Victoria H Cowling
- Centre for Gene Regulation and Expression, School of Life SciencesUniversity of DundeeDundeeUK
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Wang L, Huang D, Huang C, Yin Y, Vali K, Zhang M, Tang Y. Enhanced human somatic cell reprogramming efficiency by fusion of the MYC transactivation domain and OCT4. Stem Cell Res 2017; 25:88-97. [PMID: 29125994 DOI: 10.1016/j.scr.2017.10.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 10/20/2017] [Accepted: 10/23/2017] [Indexed: 11/28/2022] Open
Abstract
The development of human induced pluripotent stem cells (iPSCs) holds great promise for regenerative medicine. However the iPSC induction efficiency is still very low and with lengthy reprogramming process. We utilized the highly potent transactivation domain (TAD) of MYC protein to engineer the human OCT4 fusion proteins. Applying the MYC-TAD-OCT4 fusion proteins in mouse iPSC generation leads to shorter reprogramming dynamics, with earlier activation of pluripotent markers in reprogrammed cells than wild type OCT4 (wt-OCT4). Dramatic enhancement of iPSC colony induction efficiency and shortened reprogramming dynamics were observed when these MYC-TAD-OCT4 fusion proteins were used to reprogram primary human cells. The OCT4 fusion proteins induced human iPSCs are pluripotent. We further show that the MYC Box I (MBI) is dispensable while both MBII and the linking region between MBI/II are essential for the enhanced reprogramming activity of MYC-TAD-OCT4 fusion protein. Consistent with an enhanced transcription activity, the engineered OCT4 significantly stimulated the expression of genes specifically targeted by OCT4-alone, OCT4/SOX2, and OCT4/SOX2/KLF4 during human iPSC induction, compared with the wt-OCT4. The MYC-TAD-OCT4 fusion proteins we generated will be valuable tools for studying the reprogramming mechanisms and for efficient iPSC generation for humans as well as for other species.
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Affiliation(s)
- Ling Wang
- Department of Animal Science, Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
| | - Delun Huang
- Department of Animal Science, Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA; State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Animal Reproduction Institute, Guangxi University, Nanning, Guangxi, China
| | - Chang Huang
- Department of Animal Science, Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
| | - Yexuan Yin
- Department of Animal Science, Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
| | - Kaneha Vali
- Department of Animal Science, Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
| | - Ming Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Animal Reproduction Institute, Guangxi University, Nanning, Guangxi, China
| | - Young Tang
- Department of Animal Science, Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA.
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40
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PAF1 complex component Leo1 helps recruit Drosophila Myc to promoters. Proc Natl Acad Sci U S A 2017; 114:E9224-E9232. [PMID: 29078288 DOI: 10.1073/pnas.1705816114] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The Myc oncogene is a transcription factor with a powerful grip on cellular growth and proliferation. The physical interaction of Myc with the E-box DNA motif has been extensively characterized, but it is less clear whether this sequence-specific interaction is sufficient for Myc's binding to its transcriptional targets. Here we identify the PAF1 complex, and specifically its component Leo1, as a factor that helps recruit Myc to target genes. Since the PAF1 complex is typically associated with active genes, this interaction with Leo1 contributes to Myc targeting to open promoters.
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41
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Kumari A, Folk WP, Sakamuro D. The Dual Roles of MYC in Genomic Instability and Cancer Chemoresistance. Genes (Basel) 2017; 8:genes8060158. [PMID: 28590415 PMCID: PMC5485522 DOI: 10.3390/genes8060158] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 05/31/2017] [Accepted: 06/01/2017] [Indexed: 12/18/2022] Open
Abstract
Cancer is associated with genomic instability and aging. Genomic instability stimulates tumorigenesis, whereas deregulation of oncogenes accelerates DNA replication and increases genomic instability. It is therefore reasonable to assume a positive feedback loop between genomic instability and oncogenic stress. Consistent with this premise, overexpression of the MYC transcription factor increases the phosphorylation of serine 139 in histone H2AX (member X of the core histone H2A family), which forms so-called γH2AX, the most widely recognized surrogate biomarker of double-stranded DNA breaks (DSBs). Paradoxically, oncogenic MYC can also promote the resistance of cancer cells to chemotherapeutic DNA-damaging agents such as cisplatin, clearly implying an antagonistic role of MYC in genomic instability. In this review, we summarize the underlying mechanisms of the conflicting functions of MYC in genomic instability and discuss when and how the oncoprotein exerts the contradictory roles in induction of DSBs and protection of cancer-cell genomes.
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Affiliation(s)
- Alpana Kumari
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
- Tumor Signaling and Angiogenesis Program, Georgia Cancer Center, Augusta University, Augusta, GA 30912, USA.
| | - Watson P Folk
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
- Tumor Signaling and Angiogenesis Program, Georgia Cancer Center, Augusta University, Augusta, GA 30912, USA.
- Biochemistry and Cancer Biology Program, The Graduate School, Augusta University, Augusta, GA 30912, USA.
| | - Daitoku Sakamuro
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
- Tumor Signaling and Angiogenesis Program, Georgia Cancer Center, Augusta University, Augusta, GA 30912, USA.
- Biochemistry and Cancer Biology Program, The Graduate School, Augusta University, Augusta, GA 30912, USA.
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42
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MYCN amplified neuroblastoma requires the mRNA translation regulator eEF2 kinase to adapt to nutrient deprivation. Cell Death Differ 2017; 24:1564-1576. [PMID: 28574509 DOI: 10.1038/cdd.2017.79] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 04/08/2017] [Accepted: 04/13/2017] [Indexed: 01/01/2023] Open
Abstract
MYC family proteins are implicated in many human cancers, but their therapeutic targeting has proven challenging. MYCN amplification in childhood neuroblastoma (NB) is associated with aggressive disease and high mortality. Novel and effective therapeutic strategies are therefore urgently needed for these tumors. MYC-driven oncogenic transformation impairs cell survival under nutrient deprivation (ND), a characteristic stress condition within the tumor microenvironment. We recently identified eukaryotic Elongation Factor 2 Kinase (eEF2K) as a pivotal mediator of the adaptive response of tumor cells to ND. We therefore hypothesized that eEF2K facilitates the adaptation of MYCN amplified NB to ND, and that inhibiting this pathway can impair MYCN-driven NB progression. To test our hypothesis, we first analyzed publicly available genomic databases and tissue microarrays for eEF2K expression in NB, and for links between eEF2K, MYCN, and clinical outcome in NB. Effects of eEF2K inhibition were evaluated on survival of MYCN amplified versus non-amplified NB cell lines under ND. Finally, NB xenograft mouse models were used to confirm in vitro observations. Our results indicate that high eEF2K expression and activity are strongly predictive of poor outcome in NB, and correlates significantly with MYCN amplification. Inhibition of eEF2K markedly decreases survival of MYCN amplified NB cell lines in vitro under ND. Growth of MYCN amplified NB xenografts is markedly impaired by eEF2K knockdown, particularly under caloric restriction. In summary, eEF2K protects MYCN overexpressing NB cells from ND in vitro and in vivo, highlighting this kinase as a critical mediator of the adaptive response of MYCN amplified NB cells to metabolic stress.
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43
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Kalkat M, De Melo J, Hickman KA, Lourenco C, Redel C, Resetca D, Tamachi A, Tu WB, Penn LZ. MYC Deregulation in Primary Human Cancers. Genes (Basel) 2017; 8:genes8060151. [PMID: 28587062 PMCID: PMC5485515 DOI: 10.3390/genes8060151] [Citation(s) in RCA: 245] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 05/19/2017] [Accepted: 05/19/2017] [Indexed: 12/12/2022] Open
Abstract
MYC regulates a complex biological program by transcriptionally activating and repressing its numerous target genes. As such, MYC is a master regulator of many processes, including cell cycle entry, ribosome biogenesis, and metabolism. In cancer, the activity of the MYC transcriptional network is frequently deregulated, contributing to the initiation and maintenance of disease. Deregulation often leads to constitutive overexpression of MYC, which can be achieved through gross genetic abnormalities, including copy number alterations, chromosomal translocations, increased enhancer activity, or through aberrant signal transduction leading to increased MYC transcription or increased MYC mRNA and protein stability. Herein, we summarize the frequency and modes of MYC deregulation and describe both well-established and more recent findings in a variety of cancer types. Notably, these studies have highlighted that with an increased appreciation for the basic mechanisms deregulating MYC in cancer, new therapeutic vulnerabilities can be discovered and potentially exploited for the inhibition of this potent oncogene in cancer.
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Affiliation(s)
- Manpreet Kalkat
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada.
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada.
| | - Jason De Melo
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada.
| | - Katherine Ashley Hickman
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada.
- Sunnybrook Research Institute, Toronto, ON M4N 3M5, Canada.
| | - Corey Lourenco
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada.
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada.
| | - Cornelia Redel
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada.
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada.
| | - Diana Resetca
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada.
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada.
| | - Aaliya Tamachi
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada.
| | - William B Tu
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada.
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada.
| | - Linda Z Penn
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada.
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada.
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c-Myc co-ordinates mRNA cap methylation and ribosomal RNA production. Biochem J 2016; 474:377-384. [PMID: 27934633 PMCID: PMC5247799 DOI: 10.1042/bcj20160930] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 11/24/2016] [Accepted: 12/01/2016] [Indexed: 01/11/2023]
Abstract
The mRNA cap is a structure added to RNA pol II transcripts in eukaryotes, which recruits factors involved in RNA processing, nuclear export and translation initiation. RNA guanine-7 methyltransferase (RNMT)–RNA-activating miniprotein (RAM), the mRNA cap methyltransferase complex, completes the basic functional mRNA cap structure, cap 0, by methylating the cap guanosine. Here, we report that RNMT–RAM co-ordinates mRNA processing with ribosome production. Suppression of RNMT–RAM reduces synthesis of the 45S ribosomal RNA (rRNA) precursor. RNMT–RAM is required for c-Myc expression, a major regulator of RNA pol I, which synthesises 45S rRNA. Constitutive expression of c-Myc restores rRNA synthesis when RNMT–RAM is suppressed, indicating that RNMT–RAM controls rRNA production predominantly by controlling c-Myc expression. We report that RNMT–RAM is recruited to the ribosomal DNA locus, which may contribute to rRNA synthesis in certain contexts.
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45
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Posternak V, Ung MH, Cheng C, Cole MD. MYC Mediates mRNA Cap Methylation of Canonical Wnt/β-Catenin Signaling Transcripts By Recruiting CDK7 and RNA Methyltransferase. Mol Cancer Res 2016; 15:213-224. [PMID: 27899423 DOI: 10.1158/1541-7786.mcr-16-0247] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 10/26/2016] [Accepted: 11/04/2016] [Indexed: 11/16/2022]
Abstract
MYC is a pleiotropic transcription factor that activates and represses a wide range of target genes and is frequently deregulated in human tumors. While much is known about the role of MYC in transcriptional activation and repression, MYC can also regulate mRNA cap methylation through a mechanism that has remained poorly understood. Here, it is reported that MYC enhances mRNA cap methylation of transcripts globally, specifically increasing mRNA cap methylation of genes involved in Wnt/β-catenin signaling. Elevated mRNA cap methylation of Wnt signaling transcripts in response to MYC leads to augmented translational capacity, elevated protein levels, and enhanced Wnt signaling activity. Mechanistic evidence indicates that MYC promotes recruitment of RNA methyltransferase (RNMT) to Wnt signaling gene promoters by enhancing phosphorylation of serine 5 on the RNA polymerase II carboxy-terminal domain, mediated in part through an interaction between the TIP60 acetyltransferase complex and TFIIH. IMPLICATIONS MYC enhances mRNA cap methylation above and beyond transcriptional induction. Mol Cancer Res; 15(2); 213-24. ©2016 AACR.
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Affiliation(s)
- Valeriya Posternak
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, New Hampshire
| | - Matthew H Ung
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, New Hampshire
| | - Chao Cheng
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, New Hampshire
| | - Michael D Cole
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center, Lebanon, New Hampshire.
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Abstract
The mRNA cap structure, which is added to nascent RNA pol II transcripts, recruits the protein complexes required for pre-mRNA transcript processing, mRNA export and translation initiation. The enzymes which catalyze mRNA cap synthesis are regulated by cellular signaling pathways which impact on their expression, localization and activity. Here we discuss the recent observation that the mRNA cap methyltransferase, RNMT, is phosphorylated on Thr-77 by CDK1-cyclin B1, which regulates its activity and the proteins with which it interacts. RNMT Thr-77 phosphorylation provides a burst of mRNA cap methyltransferase activity during early G1 phase at a time when transcription is reactivated following completion of the cell cycle. This co-ordination of transcription and mRNA capping makes an important contribution to gene expression in the cell; preventing RNMT Thr-77 phosphorylation inhibits cell proliferation. Here we discuss these findings and how mRNA cap synthesis may be regulated in other scenarios.
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Affiliation(s)
- Michael Aregger
- a Centre for Gene Regulation and Expression , School of Life Sciences, University of Dundee , Dundee , UK
| | - Victoria H Cowling
- a Centre for Gene Regulation and Expression , School of Life Sciences, University of Dundee , Dundee , UK
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47
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Aregger M, Kaskar A, Varshney D, Fernandez-Sanchez ME, Inesta-Vaquera FA, Weidlich S, Cowling VH. CDK1-Cyclin B1 Activates RNMT, Coordinating mRNA Cap Methylation with G1 Phase Transcription. Mol Cell 2016; 61:734-746. [PMID: 26942677 PMCID: PMC4781437 DOI: 10.1016/j.molcel.2016.02.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 12/11/2015] [Accepted: 02/05/2016] [Indexed: 12/22/2022]
Abstract
The creation of translation-competent mRNA is dependent on RNA polymerase II transcripts being modified by addition of the 7-methylguanosine (m7G) cap. The factors that mediate splicing, nuclear export, and translation initiation are recruited to the transcript via the cap. The cap structure is formed by several activities and completed by RNMT (RNA guanine-7 methyltransferase), which catalyzes N7 methylation of the cap guanosine. We report that CDK1-cyclin B1 phosphorylates the RNMT regulatory domain on T77 during G2/M phase of the cell cycle. RNMT T77 phosphorylation activates the enzyme both directly and indirectly by inhibiting interaction with KPNA2, an RNMT inhibitor. RNMT T77 phosphorylation results in elevated m7G cap methyltransferase activity at the beginning of G1 phase, coordinating mRNA capping with the burst of transcription that occurs following nuclear envelope reformation. RNMT T77 phosphorylation is required for the production of cohort of proteins, and inhibiting T77 phosphorylation reduces the cell proliferation rate.
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Affiliation(s)
- Michael Aregger
- Centre for Gene Regulation and Expression/MRC Phosphorylation and Ubiquitylation, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Aneesa Kaskar
- Centre for Gene Regulation and Expression/MRC Phosphorylation and Ubiquitylation, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Dhaval Varshney
- Centre for Gene Regulation and Expression/MRC Phosphorylation and Ubiquitylation, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Maria Elena Fernandez-Sanchez
- Centre for Gene Regulation and Expression/MRC Phosphorylation and Ubiquitylation, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Francisco A Inesta-Vaquera
- Centre for Gene Regulation and Expression/MRC Phosphorylation and Ubiquitylation, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Simone Weidlich
- Division of Signal Transduction Therapy, University of Dundee, Dundee DD1 5EH, UK
| | - Victoria H Cowling
- Centre for Gene Regulation and Expression/MRC Phosphorylation and Ubiquitylation, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
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48
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mRNA Cap Methylation in Pluripotency and Differentiation. Cell Rep 2016; 16:1352-1365. [PMID: 27452456 PMCID: PMC4977272 DOI: 10.1016/j.celrep.2016.06.089] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Revised: 05/24/2016] [Accepted: 06/24/2016] [Indexed: 11/26/2022] Open
Abstract
The mRNA cap recruits factors essential for transcript processing and translation initiation. We report that regulated mRNA cap methylation is a feature of embryonic stem cell (ESC) differentiation. Expression of the mRNA cap methyltransferase activating subunit RAM is elevated in ESCs, resulting in high levels of mRNA cap methylation and expression of a cohort of pluripotency-associated genes. During neural differentiation, RAM is suppressed, resulting in repression of pluripotency-associated factors and expression of a cohort of neural-associated genes. An established requirement of differentiation is increased ERK1/2 activity, which suppresses pluripotency-associated genes. During differentiation, ERK1/2 phosphorylates RAM serine-36, targeting it for ubiquitination and proteasomal degradation, ultimately resulting in changes in gene expression associated with loss of pluripotency. Elevated RAM expression also increases the efficiency of fibroblast reprogramming. Thus, the mRNA cap emerges as a dynamic mark that instructs change in gene expression profiles during differentiation and reprogramming. The mRNA cap methyltransferase RNMT-RAM is highly expressed in embryonic stem cells RNMT-RAM is important for the expression of pluripotency-associated genes During neural differentiation, the cap methyltransferase activator RAM is repressed Repression of RAM contributes to upregulation of neural genes and neural morphology
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49
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Varshney D, Petit AP, Bueren-Calabuig JA, Jansen C, Fletcher DA, Peggie M, Weidlich S, Scullion P, Pisliakov AV, Cowling VH. Molecular basis of RNA guanine-7 methyltransferase (RNMT) activation by RAM. Nucleic Acids Res 2016; 44:10423-10436. [PMID: 27422871 PMCID: PMC5137418 DOI: 10.1093/nar/gkw637] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/16/2016] [Accepted: 07/06/2016] [Indexed: 01/16/2023] Open
Abstract
Maturation and translation of mRNA in eukaryotes requires the addition of the 7-methylguanosine cap. In vertebrates, the cap methyltransferase, RNA guanine-7 methyltransferase (RNMT), has an activating subunit, RNMT-Activating Miniprotein (RAM). Here we report the first crystal structure of the human RNMT in complex with the activation domain of RAM. A relatively unstructured and negatively charged RAM binds to a positively charged surface groove on RNMT, distal to the active site. This results in stabilisation of a RNMT lobe structure which co-evolved with RAM and is required for RAM binding. Structure-guided mutagenesis and molecular dynamics simulations reveal that RAM stabilises the structure and positioning of the RNMT lobe and the adjacent α-helix hinge, resulting in optimal positioning of helix A which contacts substrates in the active site. Using biophysical and biochemical approaches, we observe that RAM increases the recruitment of the methyl donor, AdoMet (S-adenosyl methionine), to RNMT. Thus we report the mechanism by which RAM allosterically activates RNMT, allowing it to function as a molecular rheostat for mRNA cap methylation.
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Affiliation(s)
- Dhaval Varshney
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.,MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Alain-Pierre Petit
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Juan A Bueren-Calabuig
- Computational Biology, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.,Physics, School of Science and Engineering, University of Dundee, Nethergate, Dundee DD1 5EH, UK
| | - Chimed Jansen
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Dan A Fletcher
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Mark Peggie
- Division of Signal Transduction Therapies, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Simone Weidlich
- Division of Signal Transduction Therapies, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Paul Scullion
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Andrei V Pisliakov
- Computational Biology, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.,Physics, School of Science and Engineering, University of Dundee, Nethergate, Dundee DD1 5EH, UK
| | - Victoria H Cowling
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK .,MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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50
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Abstract
MYC is a transcription factor, which not only directly modulates multiple aspects of transcription and co‐transcriptional processing (e.g. RNA‐Polymerase II initiation, elongation, and mRNA capping), but also indirectly influences several steps of RNA metabolism, including both constitutive and alternative splicing, mRNA stability, and translation efficiency. As MYC is an oncoprotein whose expression is deregulated in multiple human cancers, identifying its critical downstream activities in tumors is of key importance for designing effective therapeutic strategies. With this knowledge and recent technological advances, we now have multiple angles to reach the goal of targeting MYC in tumors, ranging from the direct reduction of MYC levels, to the dampening of selected house‐keeping functions in MYC‐overexpressing cells, to more targeted approaches based on MYC‐induced secondary effects.
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Affiliation(s)
- Cheryl M Koh
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore
| | - Arianna Sabò
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia (IIT), Milan, Italy
| | - Ernesto Guccione
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,National Cancer Centre Singapore, Singapore
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