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Jin B, Zhu J, Pan T, Yang Y, Liang L, Zhou Y, Zhang T, Teng Y, Wang Z, Wang X, Tian Q, Guo B, Li H, Chen T. MEN1 is a regulator of alternative splicing and prevents R-loop-induced genome instability through suppression of RNA polymerase II elongation. Nucleic Acids Res 2023; 51:7951-7971. [PMID: 37395406 PMCID: PMC10450199 DOI: 10.1093/nar/gkad548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 06/02/2023] [Accepted: 06/15/2023] [Indexed: 07/04/2023] Open
Abstract
The fidelity of alternative splicing (AS) patterns is essential for growth development and cell fate determination. However, the scope of the molecular switches that regulate AS remains largely unexplored. Here we show that MEN1 is a previously unknown splicing regulatory factor. MEN1 deletion resulted in reprogramming of AS patterns in mouse lung tissue and human lung cancer cells, suggesting that MEN1 has a general function in regulating alternative precursor mRNA splicing. MEN1 altered exon skipping and the abundance of mRNA splicing isoforms of certain genes with suboptimal splice sites. Chromatin immunoprecipitation and chromosome walking assays revealed that MEN1 favored the accumulation of RNA polymerase II (Pol II) in regions encoding variant exons. Our data suggest that MEN1 regulates AS by slowing the Pol II elongation rate and that defects in these processes trigger R-loop formation, DNA damage accumulation and genome instability. Furthermore, we identified 28 MEN1-regulated exon-skipping events in lung cancer cells that were closely correlated with survival in patients with lung adenocarcinoma, and MEN1 deficiency sensitized lung cancer cells to splicing inhibitors. Collectively, these findings led to the identification of a novel biological role for menin in maintaining AS homeostasis and link this role to the regulation of cancer cell behavior.
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Affiliation(s)
- Bangming Jin
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Department of Surgery, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Jiamei Zhu
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Ting Pan
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Yunqiao Yang
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Department of Surgery, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Li Liang
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Yuxia Zhou
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Tuo Zhang
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Yin Teng
- Department of Surgery, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
- Guizhou Institute of Precision Medicine, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
| | - Ziming Wang
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Xuyan Wang
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Qianting Tian
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Institute of Precision Medicine, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
| | - Bing Guo
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Haiyang Li
- Department of Surgery, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
- Guizhou Institute of Precision Medicine, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
| | - Tengxiang Chen
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Department of Surgery, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
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Duan S, Sheriff S, Elvis-Offiah UB, Witten BL, Sawyer TW, Sundaresan S, Cierpicki T, Grembecka J, Merchant JL. Clinically Defined Mutations in MEN1 Alter Its Tumor-suppressive Function Through Increased Menin Turnover. CANCER RESEARCH COMMUNICATIONS 2023; 3:1318-1334. [PMID: 37492626 PMCID: PMC10364643 DOI: 10.1158/2767-9764.crc-22-0522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 05/02/2023] [Accepted: 06/26/2023] [Indexed: 07/27/2023]
Abstract
Loss of the tumor suppressor protein menin is a critical event underlying the formation of neuroendocrine tumors (NET) in hormone-expressing tissues including gastrinomas. While aberrant expression of menin impairs its tumor suppression, few studies explore the structure-function relationship of clinical multiple endocrine neoplasia, type 1 (MEN1) mutations in the absence of a complete LOH at both loci. Here, we determined whether clinical MEN1 mutations render nuclear menin unstable and lead to its functional inactivation. We studied the structural and functional implications of two clinical MEN1 mutations (R516fs, E235K) and a third variant (A541T) recently identified in 10 patients with gastroenteropancreatic (GEP)-NETs. We evaluated the subcellular localization and half-lives of the mutants and variant in Men1-null mouse embryo fibroblast cells and in hormone-expressing human gastric adenocarcinoma and NET cell lines. Loss of menin function was assessed by cell proliferation and gastrin gene expression assays. Finally, we evaluated the effect of the small-molecule compound MI-503 on stabilizing nuclear menin expression and function in vitro and in a previously reported mouse model of gastric NET development. Both the R516fs and E235K mutants exhibited severe defects in total and subcellular expression of menin, and this was consistent with reduced half-lives of these mutants. Mutated menin proteins exhibited loss of function in suppressing tumor cell proliferation and gastrin expression. Treatment with MI-503 rescued nuclear menin expression and attenuated hypergastrinemia and gastric hyperplasia in NET-bearing mice. Clinically defined MEN1 mutations and a germline variant confer pathogenicity by destabilizing nuclear menin expression. Significance We examined the function of somatic and germline mutations and a variant of MEN1 sequenced from gastroenteropancreatic NETs. We report that these mutations and variant promote tumor cell growth and gastrin expression by rendering menin protein unstable and prone to increased degradation. We demonstrate that the menin-MLL (mixed lineage leukemia) inhibitor MI-503 restores menin protein expression and function in vitro and in vivo, suggesting a potential novel therapeutic approach to target MEN1 GEP-NETs.
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Affiliation(s)
- Suzann Duan
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Arizona College of Medicine, Tucson, Arizona
| | - Sulaiman Sheriff
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Arizona College of Medicine, Tucson, Arizona
| | - Uloma B. Elvis-Offiah
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Arizona College of Medicine, Tucson, Arizona
- Department of Physiology, University of Arizona College of Medicine, Tucson, Arizona
| | - Brandon L. Witten
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Arizona College of Medicine, Tucson, Arizona
| | - Travis W. Sawyer
- Department of Optical Sciences, University of Arizona Wyant College of Optical Sciences, Tucson, Arizona
| | - Sinju Sundaresan
- Department of Physiology, Midwestern University, Downers Grove, Illinois
| | - Tomasz Cierpicki
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | - Jolanta Grembecka
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | - Juanita L. Merchant
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Arizona College of Medicine, Tucson, Arizona
- Department of Physiology, University of Arizona College of Medicine, Tucson, Arizona
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Antisense Oligonucleotide-Based Therapeutic against Menin for Triple-Negative Breast Cancer Treatment. Biomedicines 2021; 9:biomedicines9070795. [PMID: 34356858 PMCID: PMC8301388 DOI: 10.3390/biomedicines9070795] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 06/20/2021] [Accepted: 06/30/2021] [Indexed: 01/01/2023] Open
Abstract
The tumor suppressor menin has dual functions, acting either as a tumor suppressor or as an oncogene/oncoprotein, depending on the oncological context. Triple-negative breast cancer (TNBC) is characterized by the lack of expression of the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (ERBB2/HER2) and is often a basal-like breast cancer. TNBC is associated with a dismal prognosis and an insufficient response to chemotherapies. Previously, menin was shown to play a proliferative role in ER-positive breast cancer; however, the functions of menin in TNBC remain unknown. Here, we have demonstrated that menin is expressed in various TNBC subtypes with the strongest expression in the TNBC Hs 578T cells. The depletion of menin by an antisense oligonucleotide (ASO) inhibits cell proliferation, enhances apoptosis in Hs 578T cells, highlighting the oncogenic functions of menin in this TNBC model. ASO-based menin silencing also delays the tumor progression of TNBC xenografts. Analysis of the menin interactome suggests that menin could drive TNBC tumorigenesis through the regulation of MLL/KMT2A-driven transcriptional activity, mRNA 3′-end processing and apoptosis. The study provides a rationale behind the use of ASO-based therapy, targeting menin in monotherapy or in combination with chemo or PARP inhibitors for menin-positive TNBC treatments.
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Brandi ML, Agarwal SK, Perrier ND, Lines KE, Valk GD, Thakker RV. Multiple Endocrine Neoplasia Type 1: Latest Insights. Endocr Rev 2021; 42:133-170. [PMID: 33249439 PMCID: PMC7958143 DOI: 10.1210/endrev/bnaa031] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Indexed: 02/06/2023]
Abstract
Multiple endocrine neoplasia type 1 (MEN1), a rare tumor syndrome that is inherited in an autosomal dominant pattern, is continuing to raise great interest for endocrinology, gastroenterology, surgery, radiology, genetics, and molecular biology specialists. There have been 2 major clinical practice guidance papers published in the past 2 decades, with the most recent published 8 years ago. Since then, several new insights on the basic biology and clinical features of MEN1 have appeared in the literature, and those data are discussed in this review. The genetic and molecular interactions of the MEN1-encoded protein menin with transcription factors and chromatin-modifying proteins in cell signaling pathways mediated by transforming growth factor β/bone morphogenetic protein, a few nuclear receptors, Wnt/β-catenin, and Hedgehog, and preclinical studies in mouse models have facilitated the understanding of the pathogenesis of MEN1-associated tumors and potential pharmacological interventions. The advancements in genetic diagnosis have offered a chance to recognize MEN1-related conditions in germline MEN1 mutation-negative patients. There is rapidly accumulating knowledge about clinical presentation in children, adolescents, and pregnancy that is translatable into the management of these very fragile patients. The discoveries about the genetic and molecular signatures of sporadic neuroendocrine tumors support the development of clinical trials with novel targeted therapies, along with advancements in diagnostic tools and surgical approaches. Finally, quality of life studies in patients affected by MEN1 and related conditions represent an effort necessary to develop a pharmacoeconomic interpretation of the problem. Because advances are being made both broadly and in focused areas, this timely review presents and discusses those studies collectively.
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Affiliation(s)
| | | | - Nancy D Perrier
- The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | | | - Gerlof D Valk
- University Medical Center Utrecht, CX Utrecht, the Netherlands
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5
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Bocchini M, Nicolini F, Severi S, Bongiovanni A, Ibrahim T, Simonetti G, Grassi I, Mazza M. Biomarkers for Pancreatic Neuroendocrine Neoplasms (PanNENs) Management-An Updated Review. Front Oncol 2020; 10:831. [PMID: 32537434 PMCID: PMC7267066 DOI: 10.3389/fonc.2020.00831] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Accepted: 04/28/2020] [Indexed: 12/14/2022] Open
Abstract
Pancreatic neuroendocrine tumors (PanNENs) are rare sporadic cancers or develop as part of hereditary syndromes. PanNENs can be both functioning and non-functioning based on whether they produce bioactive peptides. Some PanNENs are well differentiated while others-poorly. Symptoms, thus, depend on both oncological and hormonal causes. PanNEN diagnosis and treatment benefit from and in some instances are guided by biomarker monitoring. However, plasmatic monoanalytes are only suggestive of PanNEN pathological status and their positivity is typically followed by deepen diagnostic analyses through imaging techniques. There is a strong need for new biomarkers and follow-up modalities aimed to improve the outcome of PanNEN patients. Liquid biopsy follow-up, i.e., sequential analysis on tumor biomarkers in body fluids offers a great potential, that need to be substantiated by additional studies focusing on the specific markers and the timing of the analyses. This review provides the most updated panorama on PanNEN biomarkers.
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Affiliation(s)
- Martine Bocchini
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy
| | - Fabio Nicolini
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy
| | - Stefano Severi
- Nuclear Medicine and Radiometabolic Units, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy
| | - Alberto Bongiovanni
- Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy
| | - Toni Ibrahim
- Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy
| | - Giorgia Simonetti
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy
| | - Ilaria Grassi
- Nuclear Medicine and Radiometabolic Units, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy
| | - Massimiliano Mazza
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy
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6
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Saleh R, Taha RZ, Sasidharan Nair V, Alajez NM, Elkord E. PD-L1 Blockade by Atezolizumab Downregulates Signaling Pathways Associated with Tumor Growth, Metastasis, and Hypoxia in Human Triple Negative Breast Cancer. Cancers (Basel) 2019; 11:E1050. [PMID: 31349612 PMCID: PMC6721435 DOI: 10.3390/cancers11081050] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 07/16/2019] [Accepted: 07/22/2019] [Indexed: 12/11/2022] Open
Abstract
Triple negative breast cancer (TNBC) is the most aggressive type of breast cancer, which shows resistance to common breast cancer therapies, as it lacks the expression of the most common breast cancer targets. Therefore, TNBC treatment remains a challenge. Targeting programmed cell death-ligand 1 (PD-L1) by monoclonal antibodies (mAbs), for example, atezolizumab, has revolutionized the treatment for various cancer types. However, the therapeutic efficacy of targeting PD-L1 in TNBC is currently under investigation. In this study, we investigated the molecular mechanisms by which the human TNBC cell line MDA-MB-231, expressing PD-L1, responds to atezolizumab, using RNA-Seq. Transcriptome analysis revealed 388 upregulated and 362 downregulated genes in response to atezolizumab treatment. The expression of selected genes, from RNA-Seq data, was subsequently validated using RT-qPCR in the MDA-MB-231 and MDA-MB-468 TNBC cells following atezolizumab treatment. Bioinformatics analysis revealed that atezolizumab downregulates genes promoting cell migration/invasion and metastasis, epithelial-mesenchymal transition (EMT), cell growth/proliferation/survival, and hypoxia. On the contrary, genes associated with apoptosis and DNA repair were upregulated in response to atezolizumab treatment. Gene set enrichment analyses revealed that a significant number of these genes are related to the NF-kB, PI3K/Akt/mTOR, MAPK, and CD40 signaling pathways. Using functional assays, we confirmed that atezolizumab increases MDA-MB-231 cell apoptosis/necrosis, and reduces their proliferation and viability. Collectively, our findings provide novel insights into the molecular mechanisms/signaling pathways by which atezolizumab exerts inhibitory effects on TNBC, thereby inhibiting EMT/metastasis, tumor growth/survival, and the induction of hypoxia.
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Affiliation(s)
- Reem Saleh
- Cancer Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha P.O. Box 34110, Qatar
| | - Rowaida Z Taha
- Cancer Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha P.O. Box 34110, Qatar
| | - Varun Sasidharan Nair
- Cancer Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha P.O. Box 34110, Qatar
| | - Nehad M Alajez
- Cancer Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha P.O. Box 34110, Qatar
| | - Eyad Elkord
- Cancer Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha P.O. Box 34110, Qatar.
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7
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Mafficini A, Scarpa A. Genetics and Epigenetics of Gastroenteropancreatic Neuroendocrine Neoplasms. Endocr Rev 2019; 40:506-536. [PMID: 30657883 PMCID: PMC6534496 DOI: 10.1210/er.2018-00160] [Citation(s) in RCA: 130] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 12/27/2018] [Indexed: 12/11/2022]
Abstract
Gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs) are heterogeneous regarding site of origin, biological behavior, and malignant potential. There has been a rapid increase in data publication during the last 10 years, mainly driven by high-throughput studies on pancreatic and small intestinal neuroendocrine tumors (NETs). This review summarizes the present knowledge on genetic and epigenetic alterations. We integrated the available information from each compartment to give a pathway-based overview. This provided a summary of the critical alterations sustaining neoplastic cells. It also highlighted similarities and differences across anatomical locations and points that need further investigation. GEP-NENs include well-differentiated NETs and poorly differentiated neuroendocrine carcinomas (NECs). NENs are graded as G1, G2, or G3 based on mitotic count and/or Ki-67 labeling index, NECs are G3 by definition. The distinction between NETs and NECs is also linked to their genetic background, as TP53 and RB1 inactivation in NECs set them apart from NETs. A large number of genetic and epigenetic alterations have been reported. Recurrent changes have been traced back to a reduced number of core pathways, including DNA damage repair, cell cycle regulation, and phosphatidylinositol 3-kinase/mammalian target of rapamycin signaling. In pancreatic tumors, chromatin remodeling/histone methylation and telomere alteration are also affected. However, also owing to the paucity of disease models, further research is necessary to fully integrate and functionalize data on deregulated pathways to recapitulate the large heterogeneity of behaviors displayed by these tumors. This is expected to impact diagnostics, prognostic stratification, and planning of personalized therapy.
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Affiliation(s)
- Andrea Mafficini
- ARC-Net Center for Applied Research on Cancer, University and Hospital Trust of Verona, Verona, Italy.,Department of Diagnostics and Public Health, Section of Pathology, University and Hospital Trust of Verona, Verona, Italy
| | - Aldo Scarpa
- ARC-Net Center for Applied Research on Cancer, University and Hospital Trust of Verona, Verona, Italy.,Department of Diagnostics and Public Health, Section of Pathology, University and Hospital Trust of Verona, Verona, Italy
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8
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Xing B, Ma J, Jiang Z, Feng Z, Ling S, Szigety K, Su W, Zhang L, Jia R, Sun Y, Zhang L, Kong X, Ma X, Hua X. GLP-1 signaling suppresses menin's transcriptional block by phosphorylation in β cells. J Cell Biol 2019; 218:855-870. [PMID: 30792230 PMCID: PMC6400573 DOI: 10.1083/jcb.201805049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 10/23/2018] [Accepted: 01/07/2019] [Indexed: 12/13/2022] Open
Abstract
Both menin and glucagon-like peptide 1 (GLP-1) pathways play central yet opposing role in regulating β cell function, with menin suppressing, and GLP-1 promoting, β cell function. However, little is known as to whether or how GLP-1 pathway represses menin function. Here, we show that GLP-1 signaling-activated protein kinase A (PKA) directly phosphorylates menin at the serine 487 residue, relieving menin-mediated suppression of insulin expression and cell proliferation. Mechanistically, Ser487-phosphorylated menin gains increased binding affinity to nuclear actin/myosin IIa proteins and gets sequestrated from the Ins1 promoter. This event leads to reduced binding of repressive epigenetic histone modifiers suppressor variegation 3-9 homologue protein 1 (SUV39H1) and histone deacetylases 1 (HDAC1) at the locus and subsequently increased Ins1 gene transcription. Ser487 phosphorylation of menin also increases expression of proproliferative cyclin D2 and β cell proliferation. Our results have uncovered a previously unappreciated physiological link in which GLP-1 signaling suppresses menin function through phosphorylation-triggered and actin/myosin cytoskeletal protein-mediated derepression of gene transcription.
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Affiliation(s)
- Bowen Xing
- Shenzhen University, College of Medicine, Medical Center and Diabetes Center, Shenzhen, China
| | - Jian Ma
- Department of Cancer Biology, Abramson Family Cancer Research Institute, Institute of Diabetes, Obesity, and Metabolism, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
| | - Zongzhe Jiang
- Shenzhen University, College of Medicine, Medical Center and Diabetes Center, Shenzhen, China
| | - Zijie Feng
- Department of Cancer Biology, Abramson Family Cancer Research Institute, Institute of Diabetes, Obesity, and Metabolism, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
| | - Sunbin Ling
- Department of Cancer Biology, Abramson Family Cancer Research Institute, Institute of Diabetes, Obesity, and Metabolism, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
| | - Katy Szigety
- Department of Cancer Biology, Abramson Family Cancer Research Institute, Institute of Diabetes, Obesity, and Metabolism, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
| | - Wen Su
- Shenzhen University, College of Medicine, Medical Center and Diabetes Center, Shenzhen, China
| | - Longmei Zhang
- Shenzhen University, College of Medicine, Medical Center and Diabetes Center, Shenzhen, China
| | - Ruirui Jia
- Shenzhen University, College of Medicine, Medical Center and Diabetes Center, Shenzhen, China
| | - Yanmei Sun
- Shenzhen University, College of Medicine, Medical Center and Diabetes Center, Shenzhen, China
| | - Lin Zhang
- Shenzhen University, College of Medicine, Medical Center and Diabetes Center, Shenzhen, China
| | - Xiangchen Kong
- Shenzhen University, College of Medicine, Medical Center and Diabetes Center, Shenzhen, China
| | - Xiaosong Ma
- Shenzhen University, College of Medicine, Medical Center and Diabetes Center, Shenzhen, China
| | - Xianxin Hua
- Shenzhen University, College of Medicine, Medical Center and Diabetes Center, Shenzhen, China .,Department of Cancer Biology, Abramson Family Cancer Research Institute, Institute of Diabetes, Obesity, and Metabolism, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
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9
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Tissue-specific induced DNA methyltransferase 1 (Dnmt1) in endocrine pancreas by RCAS-TVA-based somatic gene transfer system promotes β-cell proliferation. Cancer Gene Ther 2018; 26:94-102. [PMID: 30190513 DOI: 10.1038/s41417-018-0046-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/31/2018] [Accepted: 08/05/2018] [Indexed: 12/13/2022]
Abstract
We reported that inactivation of menin (the protein product of MEN1) increases activity of Dnmt1 and mediates DNA hypermethylation in the development of multiple endocrine neoplasia type 1 (MEN1) syndrome. We have developed a RCAS-TVA-based somatic gene transfer system that enables tissue-specific delivery of Dnmt1 to individual β-cells of the pancreas in a RIP-TVA mouse model. In the present study, we mediated Dnmt1 expression in islet β-cells in RIP-TVA mice by utilizing the RCAS-TVA system to test if the upregulation of Dnmt1 can promote β-cell proliferation. In vitro, we demonstrated that upregulation of Dnmt1 increased β-cell proliferation. In vivo, our results showed that the levels of serum insulin were increased in the RIP-TVA mice with RCASBP-Dnmt1 infection compared with wild-type control mice with RCASBP-Dnmt1 infection. Furthermore, we confirmed that mRNA and protein expression of Dnmt1 as well as Dnmt1 enzyme activity were upregulated in the RIP-TVA mice with RCASBP-Dnmt1 infection compared with wild-type control mice with RCASBP-Dnmt1 infection. Finally, we demonstrated that upregulation of Dnmt1 resulted in hyperplasia through β-cell proliferation. We conclude that the upregulation of Dnmt1 promotes islet β-cell proliferation and targeting Dnmt1 may be a promising therapy for patients suffering from pancreatic neuroendocrine tumors.
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Amair-Pinedo F, Matos I, Saurí T, Hernando J, Capdevila J. The Treatment Landscape and New Opportunities of Molecular Targeted Therapies in Gastroenteropancreatic Neuroendocrine Tumors. Target Oncol 2018; 12:757-774. [PMID: 29143176 DOI: 10.1007/s11523-017-0532-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Neuroendocrine neoplasms (NENs) are a heterogeneous group of neoplasms that originate from neuroendocrine stem cells and express both neural and endocrine markers. They are found in almost every organ, and while NENs are mostly associated with slow growth, complications due to the uncontrolled secretion of active peptides, and metastatic disease, may significantly impair the quality of life and can ultimately lead to the death of affected individuals. Expanding knowledge of the genetic, epigenetic, and proteomic landscapes of NENs has led to a better understanding of their molecular pathology and consequently increased treatment options for patients. Here, we review the principal breakthroughs in NEN treatment management, owing largely to omics technologies over the last few years, current recommendations of systemic treatment, and ongoing research into the identification of predictive and response biomarkers based on molecular targeted therapies.
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Affiliation(s)
| | - Ignacio Matos
- Vall d'Hebron University Hospital, Barcelona, Spain.,Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | - Tamara Saurí
- Vall d'Hebron University Hospital, Barcelona, Spain.,Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | - Jorge Hernando
- Vall d'Hebron University Hospital, Barcelona, Spain.,Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | - Jaume Capdevila
- Vall d'Hebron University Hospital, Barcelona, Spain. .,Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain.
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11
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Yuan Z, Sánchez Claros C, Suzuki M, Maggi EC, Kaner JD, Kinstlinger N, Gorecka J, Quinn TJ, Geha R, Corn A, Pastoriza J, Jing Q, Adem A, Wu H, Alemu G, Du YC, Zheng D, Greally JM, Libutti SK. Loss of MEN1 activates DNMT1 implicating DNA hypermethylation as a driver of MEN1 tumorigenesis. Oncotarget 2017; 7:12633-50. [PMID: 26871472 PMCID: PMC4914310 DOI: 10.18632/oncotarget.7279] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 01/24/2016] [Indexed: 12/12/2022] Open
Abstract
Multiple endocrine neoplasia type 1 (MEN1) syndrome results from mutations in the MEN1 gene and causes tumor formation via largely unknown mechanisms. Using a novel genome-wide methylation analysis, we studied tissues from MEN1-parathyroid tumors, Men1 knockout (KO) mice, and Men1 null mouse embryonic fibroblast (MEF) cell lines. We demonstrated that inactivation of menin (the protein product of MEN1) increases activity of DNA (cytosine-5)-methyltransferase 1 (DNMT1) by activating retinoblastoma-binding protein 5 (Rbbp5). The increased activity of DNMT1 mediates global DNA hypermethylation, which results in aberrant activation of the Wnt/β-catenin signaling pathway through inactivation of Sox regulatory genes. Our study provides important insights into the role of menin in DNA methylation and its impact on the pathogenesis of MEN1 tumor development.
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Affiliation(s)
- Ziqiang Yuan
- Department of Surgery, Albert Einstein College of Medicine, Bronx, New York, USA
| | | | - Masako Suzuki
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Elaine C Maggi
- Department of Surgery, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Justin D Kaner
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Noah Kinstlinger
- Department of Surgery, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Jolanta Gorecka
- Department of Surgery, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Thomas J Quinn
- Department of Surgery, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Rula Geha
- Department of Surgery, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Amanda Corn
- Department of Surgery, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Jessica Pastoriza
- Department of Surgery, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Qiang Jing
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Asha Adem
- Department of Surgery, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Hao Wu
- Department of Surgery, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Girum Alemu
- Department of Surgery, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Yi-Chieh Du
- Department of Pathology and Lab Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Deyou Zheng
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, USA.,Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, USA.,Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA
| | - John M Greally
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, USA.,Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA.,Department of Pediatrics, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Steven K Libutti
- Department of Surgery, Albert Einstein College of Medicine, Bronx, New York, USA.,Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, USA
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12
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Agarwal SK. The future: genetics advances in MEN1 therapeutic approaches and management strategies. Endocr Relat Cancer 2017; 24:T119-T134. [PMID: 28899949 PMCID: PMC5679100 DOI: 10.1530/erc-17-0199] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 08/08/2017] [Indexed: 02/01/2023]
Abstract
The identification of the multiple endocrine neoplasia type 1 (MEN1) gene in 1997 has shown that germline heterozygous mutations in the MEN1 gene located on chromosome 11q13 predisposes to the development of tumors in the MEN1 syndrome. Tumor development occurs upon loss of the remaining normal copy of the MEN1 gene in MEN1-target tissues. Therefore, MEN1 is a classic tumor suppressor gene in the context of MEN1. This tumor suppressor role of the protein encoded by the MEN1 gene, menin, holds true in mouse models with germline heterozygous Men1 loss, wherein MEN1-associated tumors develop in adult mice after spontaneous loss of the remaining non-targeted copy of the Men1 gene. The availability of genetic testing for mutations in the MEN1 gene has become an essential part of the diagnosis and management of MEN1. Genetic testing is also helping to exclude mutation-negative cases in MEN1 families from the burden of lifelong clinical screening. In the past 20 years, efforts of various groups world-wide have been directed at mutation analysis, molecular genetic studies, mouse models, gene expression studies, epigenetic regulation analysis, biochemical studies and anti-tumor effects of candidate therapies in mouse models. This review will focus on the findings and advances from these studies to identify MEN1 germline and somatic mutations, the genetics of MEN1-related states, several protein partners of menin, the three-dimensional structure of menin and menin-dependent target genes. The ongoing impact of all these studies on disease prediction, management and outcomes will continue in the years to come.
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Affiliation(s)
- Sunita K Agarwal
- Metabolic Diseases BranchNational Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, USA
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13
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Feng Z, Ma J, Hua X. Epigenetic regulation by the menin pathway. Endocr Relat Cancer 2017; 24:T147-T159. [PMID: 28811300 PMCID: PMC5612327 DOI: 10.1530/erc-17-0298] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 08/15/2017] [Indexed: 02/06/2023]
Abstract
There is a trend of increasing prevalence of neuroendocrine tumors (NETs), and the inherited multiple endocrine neoplasia type 1 (MEN1) syndrome serves as a genetic model to investigate how NETs develop and the underlying mechanisms. Menin, encoded by the MEN1 gene, at least partly acts as a scaffold protein by interacting with multiple partners to regulate cellular homeostasis of various endocrine organs. Menin has multiple functions including regulation of several important signaling pathways by controlling gene transcription. Here, we focus on reviewing the recent progress in elucidating the key biochemical role of menin in epigenetic regulation of gene transcription and cell signaling, as well as posttranslational regulation of menin itself. In particular, we will review the progress in studying structural and functional interactions of menin with various histone modifiers and transcription factors such as MLL, PRMT5, SUV39H1 and other transcription factors including c-Myb and JunD. Moreover, the role of menin in regulating cell signaling pathways such as TGF-beta, Wnt and Hedgehog, as well as miRNA biogenesis and processing will be described. Further, the regulation of the MEN1 gene transcription, posttranslational modifications and stability of menin protein will be reviewed. These various modes of regulation by menin as well as regulation of menin by various biological factors broaden the view regarding how menin controls various biological processes in neuroendocrine organ homeostasis.
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Affiliation(s)
- Zijie Feng
- Department of Cancer BiologyAbramson Family Cancer Research Institute, Abramson Cancer Center, Institute of Diabetes, Obesity, and Metabolism (IDOM), University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jian Ma
- Department of Cancer BiologyAbramson Family Cancer Research Institute, Abramson Cancer Center, Institute of Diabetes, Obesity, and Metabolism (IDOM), University of Pennsylvania, Philadelphia, Pennsylvania, USA
- State Key Laboratory of Veterinary BiotechnologyHarbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, Heilongjiang, China
| | - Xianxin Hua
- Department of Cancer BiologyAbramson Family Cancer Research Institute, Abramson Cancer Center, Institute of Diabetes, Obesity, and Metabolism (IDOM), University of Pennsylvania, Philadelphia, Pennsylvania, USA
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14
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Agarwal SK. Exploring the tumors of multiple endocrine neoplasia type 1 in mouse models for basic and preclinical studies. INTERNATIONAL JOURNAL OF ENDOCRINE ONCOLOGY 2014; 1:153-161. [PMID: 25685317 DOI: 10.2217/ije.14.16] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Most patients (70-90%) with the multiple endocrine neoplasia type 1 (MEN1) syndrome possess germline heterozygous mutations in MEN1 that predisposes to tumors of multiple endocrine and nonendocrine tissues. Some endocrine tumors of the kinds seen in MEN1 that occur sporadically in the general population also possess somatic mutations in MEN1. Interestingly, the endocrine tumors of MEN1 are recapitulated in mouse models of Men1 loss that serve as a valuable resource to understand the pathophysiology and molecular basis of tumorigenesis. Exploring these endocrine tumors in mouse models using in vivo, ex vivo and in vitro methods can help to follow the process of tumorigenesis, and can be useful for preclinical testing of therapeutics and understanding their mechanisms of action.
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Affiliation(s)
- Sunita K Agarwal
- National Institutes of Health, NIDDK, Metabolic Diseases Branch, Bldg 10, Room 8C-101, Bethesda, MD 20892, USA, Tel.: +1 301 402 7834
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15
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Halperin DM, Kulke MH, Yao JC. A tale of two tumors: treating pancreatic and extrapancreatic neuroendocrine tumors. Annu Rev Med 2014; 66:1-16. [PMID: 25341008 DOI: 10.1146/annurev-med-061813-012908] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Despite their perceived rarity, gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rising in incidence and prevalence. The biology, natural history, and therapeutic options for GEP-NETs are heterogeneous: NETs arising in the pancreas can be distinguished from those arising elsewhere in the gastrointestinal tract, and therapy is dichotomized between these two groups. Somatostatin analogues are the mainstay of oncologic management of bowel NETs; everolimus, streptozocin, and sunitinib are approved to treat pancreatic NETs. There are significant differences in molecular genetics between pancreatic and extrapancreatic NETs, and studies are evaluating whether additional NET patients may benefit from targeted agents. We discuss the distinguishing features of these two groups of tumors, as well as the therapeutic implications of the distinction. We also examine the evolving therapeutic landscape and discuss the likelihood that treatment will be developed independently for pancreatic and extrapancreatic gastrointestinal NETs, with novel therapeutics effective for newly identified pathologically or molecularly defined subgroups.
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Affiliation(s)
- Daniel M Halperin
- Department of Gastrointestinal Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030; ,
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16
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Meeker A, Heaphy C. Gastroenteropancreatic endocrine tumors. Mol Cell Endocrinol 2014; 386:101-20. [PMID: 23906538 DOI: 10.1016/j.mce.2013.07.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 07/19/2013] [Accepted: 07/22/2013] [Indexed: 02/06/2023]
Abstract
Gastroenteropancreatic endocrine tumors (GEP-NETs) are relatively uncommon; comprising approximately 0.5% of all human cancers. Although they often exhibit relatively indolent clinical courses, GEP-NETs have the potential for lethal progression. Due to their scarcity and various technical challenges, GEP-NETs have been understudied. As a consequence, we have few diagnostic, prognostic and predictive biomarkers for these tumors. Early detection and surgical removal is currently the only reliable curative treatment for GEP-NET patients; many of whom, unfortunately, present with advanced disease. Here, we review the genetics and epigenetics of GEP-NETs. The last few years have witnessed unprecedented technological advances in these fields, and their application to GEP-NETS has already led to important new information on the molecular abnormalities underlying them. As outlined here, we expect that "omics" studies will provide us with new diagnostic and prognostic biomarkers, inform the development of improved pre-clinical models, and identify novel therapeutic targets for GEP-NET patients.
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Affiliation(s)
- Alan Meeker
- The Johns Hopkins University School of Medicine, Department of Pathology, Bond Street Research Annex Bldg., Room B300, 411 North Caroline Street, Baltimore, MD 21231, United States.
| | - Christopher Heaphy
- The Johns Hopkins University School of Medicine, Department of Pathology, Bond Street Research Annex Bldg., Room B300, 411 North Caroline Street, Baltimore, MD 21231, United States
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17
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Cierpicki T, Grembecka J. Challenges and opportunities in targeting the menin-MLL interaction. Future Med Chem 2014; 6:447-62. [PMID: 24635524 PMCID: PMC4138051 DOI: 10.4155/fmc.13.214] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Menin is an essential co-factor of oncogenic MLL fusion proteins and the menin-MLL interaction is critical for development of acute leukemia in vivo. Targeting the menin-MLL interaction with small molecules represents an attractive strategy to develop new anticancer agents. Recent developments, including determination of menin crystal structure and development of potent small molecule and peptidomimetic inhibitors, demonstrate the feasibility of targeting the menin-MLL interaction. On the other hand, biochemical and structural studies revealed that MLL binds to menin in a complex bivalent mode engaging two MLL motifs, and therefore inhibition of this protein-protein interaction represents a challenge. This review summarizes the most recent achievements in targeting the menin-MLL interaction as well as discusses potential benefits of blocking menin in cancer.
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Affiliation(s)
- Tomasz Cierpicki
- Author for correspondence: Tel.: +1 734 615 9324, Fax: +1 734 615 0688,
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18
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Comparative transcriptome profiling of an SV40-transformed human fibroblast (MRC5CVI) and its untransformed counterpart (MRC-5) in response to UVB irradiation. PLoS One 2013; 8:e73311. [PMID: 24019915 PMCID: PMC3760899 DOI: 10.1371/journal.pone.0073311] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 07/18/2013] [Indexed: 11/19/2022] Open
Abstract
Simian virus 40 (SV40) transforms cells through the suppression of tumor-suppressive responses by large T and small t antigens; studies on the effects of these two oncoproteins have greatly improved our knowledge of tumorigenesis. Large T antigen promotes cellular transformation by binding and inactivating p53 and pRb tumor suppressor proteins. Previous studies have shown that not all of the tumor-suppressive responses were inactivated in SV40-transformed cells; however, the underlying cause is not fully studied. In this study, we investigated the UVB-responsive transcriptome of an SV40-transformed fibroblast (MRC5CVI) and that of its untransformed counterpart (MRC-5). We found that, in response to UVB irradiation, MRC-5 and MRC5CVI commonly up-regulated the expression of oxidative phosphorylation genes. MRC-5 up-regulated the expressions of chromosome condensation, DNA repair, cell cycle arrest, and apoptotic genes, but MRC5CVI did not. Further cell death assays indicated that MRC5CVI was more sensitive than MRC-5 to UVB-induced cell death with increased caspase-3 activation; combining with the transcriptomic results suggested that MRC5CVI may undergo UVB-induced cell death through mechanisms other than transcriptional regulation. Our study provides a further understanding of the effects of SV40 transformation on cellular stress responses, and emphasizes the value of SV40-transformed cells in the researches of sensitizing neoplastic cells to radiations.
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19
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Jeronimo C, Bataille AR, Robert F. The Writers, Readers, and Functions of the RNA Polymerase II C-Terminal Domain Code. Chem Rev 2013; 113:8491-522. [DOI: 10.1021/cr4001397] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Célia Jeronimo
- Institut de recherches cliniques de Montréal, Montréal, Québec,
Canada H2W 1R7
| | - Alain R. Bataille
- Institut de recherches cliniques de Montréal, Montréal, Québec,
Canada H2W 1R7
| | - François Robert
- Institut de recherches cliniques de Montréal, Montréal, Québec,
Canada H2W 1R7
- Département
de Médecine,
Faculté de Médecine, Université de Montréal, Montréal, Québec,
Canada H3T 1J4
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20
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Menin: a scaffold protein that controls gene expression and cell signaling. Trends Biochem Sci 2013; 38:394-402. [PMID: 23850066 DOI: 10.1016/j.tibs.2013.05.005] [Citation(s) in RCA: 169] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 05/22/2013] [Accepted: 05/31/2013] [Indexed: 12/22/2022]
Abstract
The protein menin is encoded by the MEN1 gene, which is mutated in patients with multiple endocrine neoplasia type 1 (MEN1) syndrome. Although menin acts as a tumor suppressor in endocrine organs, it is required for leukemic transformation in mouse models. Menin possesses these dichotomous functions probably because it can both positively and negatively regulate gene expression, as well as interact with a multitude of proteins with diverse functions. Here, we review the recent progress in understanding the molecular mechanisms by which menin functions. The crystal structures of menin with different binding partners reveal that menin is a key scaffold protein that functionally crosstalks with various partners to regulate gene transcription and interplay with multiple signaling pathways.
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MEN1 is a melanoma tumor suppressor that preserves genomic integrity by stimulating transcription of genes that promote homologous recombination-directed DNA repair. Mol Cell Biol 2013; 33:2635-47. [PMID: 23648481 DOI: 10.1128/mcb.00167-13] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Multiple endocrine neoplasia type 1 is a familial cancer syndrome resulting from loss-of-function mutations in the MEN1 gene. We previously identified the tumor suppressor MEN1 as a gene required for oncogene-induced senescence in melanocytes, raising the possibility that MEN1 is a melanoma tumor suppressor. Here we show that MEN1 expression is lost in a high percentage of human melanomas and melanoma cell lines. We find that melanocytes depleted of MEN1 are deficient in homologous recombination (HR)-directed DNA repair, which is accompanied by increased nonhomologous end-joining activity. Following DNA damage, MEN1 levels increase as a result of phosphorylation by the DNA damage kinase ATM/ATR. Most importantly, we show that MEN1 functions by directly stimulating the transcription of several genes, including BRCA1, RAD51, and RAD51AP1, that encode proteins involved in HR. MEN1 and its coactivator, the mixed-lineage leukemia histone methyltransferase, are recruited to the BRCA1, RAD51, and RAD51AP1 promoters by estrogen receptor 1, resulting in increased histone H3-lysine 4 trimethylation and transcription. Collectively, our results indicate that MEN1 is a melanoma tumor suppressor that functions by stimulating the transcription of genes involved in HR-directed DNA repair.
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Abstract
Menin, encoded by the multiple endocrine neoplasia type 1 (MEN1) gene, is a tumor suppressor that leads to multiple endocrine tumors upon loss of its function. Menin functions as a transcriptional activator by tethering MLL complex to mediate histone H3 K4 methylation. It also functions as a repressor. However, the molecular mechanism of how menin contributes to the opposite outcome in gene expression is largely unknown. Here, we investigated the role of menin in the epigenetic regulation of transcription mediated by histone covalent modification. We show that the global methylation level of histone H3 K9, as well as H3 K4, was decreased in Men1(-/-) MEF cells. Consistently, menin was able to interact with the suppressor of variegation 3-9 homolog family protein, SUV39H1, to mediate H3 K9 methylation. This interaction decreased when patient-derived MEN1 mutation was introduced into the SUV39H1-interaction domain. We show that menin mediated different chromatin changes depending on target genes. Chromatin immunoprecipitation studies showed that menin directly associated with the GBX2 promoter and menin-dependent recruitment of SUV39H1 was essential for chromatin remodeling and transcriptional regulation. These results provide a molecular basis of how menin functions as a transcriptional repressor and suggest that menin-dependent integration of H3 K9 methylation might play an important role in preventing tumors.
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Abstract
Multiple endocrine neoplasia type 1 (MEN1) is an autosomal-dominant tumor syndrome characterized by the occurrence of tumors in multiple endocrine tissues and nonendocrine tissues. The three main endocrine tissues most frequently affected by tumors are parathyroid (95%), enteropancreatic neuroendocrine (50%) and anterior pituitary (40%). Tumors are caused by a heterozygous germline-inactivating mutation in the MEN1 gene (1st hit) followed by somatic inactivating mutation or loss of the normal copy of the gene (2nd hit), leading to complete loss of function of the encoded protein menin. Most of the disease features and tumors are recapitulated in mouse models with heterozygous germline loss of the Men1 gene. Also, tissue-specific tumors are observed in mouse models with homozygous somatic loss of the Men1 gene specifically in MEN1-associated endocrine tissues. Hence, mouse models could serve as possible surrogates for studying MEN1 and related states. To gain insights into MEN1 pathophysiology, menin-interacting partners and pathways have been identified to investigate its tumor suppressor and other functions. Also, the 3D crystal structure of menin has been deciphered which could be useful to reveal the relevance of MEN1 gene mutations and menin's interactions. This chapter covers clinical, genetic and basic findings about the MEN1 syndrome, MEN1 gene and its product protein menin.
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Affiliation(s)
- Sunita K Agarwal
- Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA. SunitaA @ mail.nih.gov
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24
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Feng ZJ, Gurung B, Jin GH, Yang XL, Hua XX. SUMO modification of menin. Am J Cancer Res 2013; 3:96-106. [PMID: 23359867 PMCID: PMC3555195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 12/27/2012] [Indexed: 06/01/2023] Open
Abstract
Menin acts as contextual a tumor suppressor and a tumor promoter, partly via epigenetic regulation of gene transcription. While menin is phosphorylated, it remains unclear whether wild type menin has other post-translational modifications. Here, we report that menin is SUMOylated by SUMO1 in vivo and in vitro, and the SUMOylation is reduced by a SUMO protease. Lysine 591 of menin was covalently modified by SUMO1 and K591R mutation in menin blocked SUMOylation of the C-terminal part of menin in transfected cells. Full-length menin with K591 mutation was still SUMOylated in vivo, suggesting the existence of multiple SUMOylation sites. Menin K591R mutant or menin-SUMO fusion protein still retains the ability to regulate cell proliferation and the expression of the examined menin target genes.
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Affiliation(s)
- Zi-Jie Feng
- Department of Basic Medical Sciences, Medical College, Xiamen University Xiamen, Fujian, China 361005 ; Abramson Family Cancer Research Institute, Department of Cancer Biology, Abramson Cancer Center, University of Pennsylvania Perelman School of Medicine 421 Curie Blvd., Philadelphia, PA 19104, USA
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25
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Ren F, Xu HW, Hu Y, Yan SH, Wang F, Su BW, Zhao Q. Expression and subcellular localization of menin in human cancer cells. Exp Ther Med 2012; 3:1087-1091. [PMID: 22970022 DOI: 10.3892/etm.2012.530] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 03/21/2012] [Indexed: 11/06/2022] Open
Abstract
The aim of this study was to elucidate the expression and localization of menin, a protein encoded by the multiple endocrine neoplasia type I (MEN1) gene, in 13 human cancer cell lines. Reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the expression of the menin gene. The localization of the menin protein was detected by immunofluorescence microscopy. Western blotting was used to determine the quantity of menin in the nucleus, cytosol and membrane of the cells. RT-PCR revealed that menin was expressed in all the cell lines examined in this study. Immunofluorescence microscopy revealed that menin was located primarily in the nucleus. In the GES-1 (transformed human gastric epithelium), MCF-7 (breast cancer), SGH44 (brain glioma) and HeLa (cervical cancer) cell lines, menin was also found to be localized to the membrane, cytosol and nucleus. Moreover, in SGH44 cells more menin was located in the cytosol than the nucleus. Similar findings were obtained by western blotting. In the GES-1 and MKN-28 cells undergoing octreotide treatment, cytoplasmic menin was significantly increased compared with the control groups. Therefore, we suggest that menin is expressed in a number of human cancer cell lines and that the cytosolic distribution increases when the cells undergo octreotide treatment, indicating a new role for menin.
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Affiliation(s)
- Feng Ren
- Departments of Clinical Laboratory, and
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26
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Canaff L, Vanbellinghen JF, Kanazawa I, Kwak H, Garfield N, Vautour L, Hendy GN. Menin missense mutants encoded by the MEN1 gene that are targeted to the proteasome: restoration of expression and activity by CHIP siRNA. J Clin Endocrinol Metab 2012; 97:E282-91. [PMID: 22090276 DOI: 10.1210/jc.2011-0241] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
CONTEXT In multiple endocrine neoplasia type 1 (MEN1) characterized by tumors of parathyroid, enteropancreas, and anterior pituitary, missense mutations in the MEN1 gene product, menin, occur in a subset of cases. The mutant proteins are degraded by the proteasome. However, whether their expression and activity can be restored is not known. OBJECTIVE Our objective was to functionally characterize a panel of 16 menin missense mutants, including W423R and S443Y identified in new MEN1 families, with respect to protein stability, targeting to the proteasome and restoration of expression by proteasome inhibitors and expression and function by small interfering RNA technology. METHODS Flag-tagged wild-type (WT) and missense menin mutant expression vectors were transiently transfected in human embryonic kidney (HEK293) and/or rat insulinoma (Rin-5F) cells. RESULTS The majority of mutants were short-lived, whereas WT menin was stable. Proteasome inhibitors MG132 and PS-341 and inhibition of the chaperone, heat-shock protein 70 (Hsp70), or the ubiquitin ligase, COOH terminus of Hsp70-interacting protein (CHIP), by specific small interfering RNA, restored the levels of the mutants, whereas that of WT menin was largely unaffected. Inhibition of CHIP restored the ability of mutants to mediate normal functions of menin: TGF-β up-regulation of the promoters of its target genes, the cyclin-dependent kinase inhibitors p15 and p21 as well as TGF-β inhibition of cell numbers. CONCLUSION When the levels of missense menin mutants that are targeted to the proteasome are normalized they may function similarly to WT menin. Potentially, targeting specific components of the proteasome chaperone pathway could be beneficial in treating a subset of MEN1 cases.
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Affiliation(s)
- Lucie Canaff
- Department of Medicine, Calcium Research Laboratory, and Hormones and Cancer Research Unit, Royal Victoria Hospital, McGill University, Montreal, Quebec H3A 1A1, Canada
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