Clinically Defined Mutations in MEN1 Alter Its Tumor-suppressive Function Through Increased Menin Turnover

Loss of the tumor suppressor protein menin is a critical event underlying the formation of neuroendocrine tumors (NETs) 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 loss of heterozygosity 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 three clinical MEN1 mutations (R516fs, E235K, and A541T) recently identified in a cohort of ten patients with GEP-NETs. We evaluated the subcellular localization and half-lives of these mutated menin variants in Men1-null mouse embryo fibroblast cells and in hormone-expressing human gastric adenocarcinoma and murine enteroendocrine tumor cell lines. Loss of menin function was assessed by cell proliferation and gastrin gene expression assays. Lastly, 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 variants exhibited severe defects in total and subcellular expression of menin, and this was consistent with reduced half-lives of these mutants. Mutated menin variants 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. Implication Clinically defined germline and somatic MEN1 mutations confer pathogenicity by destabilizing nuclear menin expression.

[1]  K. Rodenburg,et al.  Multi-omics analyses of MEN1 missense mutations identify disruption of menin–MLL and menin–JunD interactions as critical requirements for molecular pathogenicity , 2022, Epigenetics & Chromatin.

[2]  N. Syed,et al.  Neuronal Menin Overexpression Rescues Learning and Memory Phenotype in CA1-Specific α7 nAChRs KD Mice , 2021, Cells.

[3]  D. Metz,et al.  Genome analysis identifies differences in the transcriptional targets of duodenal versus pancreatic neuroendocrine tumours , 2021, BMJ open gastroenterology.

[4]  H. Timmers,et al.  A Box of Chemistry to Inhibit the MEN1 Tumor Suppressor Gene Promoting Leukemia , 2021, ChemMedChem.

[5]  J. Merchant,et al.  Interleukin-1β Suppresses Gastrin via Primary Cilia and Induces Antral Hyperplasia , 2020, Cellular and molecular gastroenterology and hepatology.

[6]  P. Marzullo,et al.  Phenotypes Associated With MEN1 Syndrome: A Focus on Genotype-Phenotype Correlations , 2020, Frontiers in Endocrinology.

[7]  Bowen Xing,et al.  Wild-type menin is rapidly degraded via the ubiquitin-proteasome pathway in a rat insulinoma cell line , 2019, Bioscience reports.

[8]  L. Busino,et al.  Disruption of the menin-MLL interaction triggers menin protein degradation via ubiquitin-proteasome pathway. , 2019, American journal of cancer research.

[9]  C. Stratakis,et al.  Multiple Endocrine Neoplasia Type 1 (MEN1): An Update and the Significance of Early Genetic and Clinical Diagnosis , 2019, Front. Endocrinol..

[10]  M. Low,et al.  Gastrin Induces Nuclear Export and Proteasome Degradation of Menin in Enteric Glial Cells. , 2017, Gastroenterology.

[11]  T. Cierpicki,et al.  Pharmacologic Inhibition of the Menin–MLL Interaction Leads to Transcriptional Repression of PEG10 and Blocks Hepatocellular Carcinoma , 2017, Molecular Cancer Therapeutics.

[12]  N. Syed,et al.  Tumor suppressor menin is required for subunit-specific nAChR α5 transcription and nAChR-dependent presynaptic facilitation in cultured mouse hippocampal neurons , 2017, Scientific Reports.

[13]  K. Qu,et al.  Menin enhances c-Myc-mediated transcription to promote cancer progression , 2017, Nature Communications.

[14]  Shivashankar H. Nagaraj,et al.  Whole-genome landscape of pancreatic neuroendocrine tumours , 2017, Nature.

[15]  Arundhati Sharma,et al.  Novel MEN 1 gene findings in rare sporadic insulinoma—a case control study , 2015, BMC Endocrine Disorders.

[16]  Bo Wen,et al.  Pharmacologic inhibition of the Menin-MLL interaction blocks progression of MLL leukemia in vivo. , 2015, Cancer cell.

[17]  S. Dhanasekaran,et al.  Targeting the MLL complex in castration resistant prostate cancer , 2015, Nature Medicine.

[18]  J. Scoazec,et al.  Altered MENIN expression disrupts the MAFA differentiation pathway in insulinoma. , 2013, Endocrine-related cancer.

[19]  J. Bilezikian,et al.  Clinical practice guidelines for multiple endocrine neoplasia type 1 (MEN1). , 2012, The Journal of clinical endocrinology and metabolism.

[20]  Johannes E. Schindelin,et al.  Fiji: an open-source platform for biological-image analysis , 2012, Nature Methods.

[21]  Jolanta Grembecka,et al.  Menin-MLL inhibitors reverse oncogenic activity of MLL fusion proteins in leukemia. , 2012, Nature chemical biology.

[22]  M. Lei,et al.  The same pocket in menin binds both MLL and JUND but has opposite effects on transcription , 2012, Nature.

[23]  G. Hendy,et al.  Menin missense mutants encoded by the MEN1 gene that are targeted to the proteasome: restoration of expression and activity by CHIP siRNA. , 2012, The Journal of clinical endocrinology and metabolism.

[24]  R. Thakker,et al.  Multiple endocrine neoplasia type 1. , 1999, Endocrine-related cancer.

[25]  J. Merchant,et al.  Menin and JunD regulate gastrin gene expression through proximal DNA elements. , 2011, American journal of physiology. Gastrointestinal and liver physiology.

[26]  Michael A. Choti,et al.  DAXX/ATRX, MEN1, and mTOR Pathway Genes Are Frequently Altered in Pancreatic Neuroendocrine Tumors , 2011, Science.

[27]  M. Meyerson,et al.  The Menin Tumor Suppressor Protein Is Phosphorylated in Response to DNA Damage , 2011, PloS one.

[28]  S. Beghelli,et al.  MEN1 in pancreatic endocrine tumors: analysis of gene and protein status in 169 sporadic neoplasms reveals alterations in the vast majority of cases. , 2010, Endocrine-related cancer.

[29]  G. Ning,et al.  Nuclear-Cytoplasmic Shuttling of Menin Regulates Nuclear Translocation of β-Catenin , 2009, Molecular and Cellular Biology.

[30]  J. Scoazec,et al.  MEN1 missense mutations impair sensitization to apoptosis induced by wild-type menin in endocrine pancreatic tumor cells. , 2008, Gastroenterology.

[31]  F. Collins,et al.  Mouse Embryo Fibroblasts Lacking the Tumor Suppressor Menin Show Altered Expression of Extracellular Matrix Protein Genes , 2007, Molecular Cancer Research.

[32]  W. Knoefel,et al.  Allelic deletion of the MEN1 gene in duodenal gastrin and somatostatin cell neoplasms and their precursor lesions , 2006, Gut.

[33]  Maho Takahashi,et al.  Menin Missense Mutants Associated with Multiple Endocrine Neoplasia Type 1 Are Rapidly Degraded via the Ubiquitin-Proteasome Pathway , 2004, Molecular and Cellular Biology.

[34]  Jun O. Liu,et al.  Menin, a tumor suppressor, represses JunD-mediated transcriptional activity by association with an mSin3A-histone deacetylase complex. , 2003, Cancer research.

[35]  A. Rosato,et al.  In situ analysis of human menin in normal and neoplastic pancreatic tissues: evidence for differential expression in exocrine and endocrine cells. , 2003, The Journal of clinical endocrinology and metabolism.

[36]  B. Ponder,et al.  Guidelines for diagnosis and therapy of MEN type 1 and type 2. , 2001, The Journal of clinical endocrinology and metabolism.

[37]  F. Collins,et al.  The tumor suppressor protein menin interacts with NF-kappaB proteins and inhibits NF-kappaB-mediated transactivation. , 2001, Oncogene.

[38]  T. Yokoi,et al.  Somatic mutations of multiple endocrine neoplasia type 1 gene in the sporadic endocrine tumors. , 1998, Laboratory investigation; a journal of technical methods and pathology.

[39]  F. Collins,et al.  Menin, the product of the MEN1 gene, is a nuclear protein. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[40]  C. Larsson,et al.  Identification of the multiple endocrine neoplasia type 1 (MEN1) gene. The European Consortium on MEN1. , 1997, Human molecular genetics.

[41]  Y Wang,et al.  Positional cloning of the gene for multiple endocrine neoplasia-type 1. , 1997, Science.

[42]  J. Merchant,et al.  cAMP regulates gastrin gene expression. , 1995, The American journal of physiology.

[43]  J. Minna,et al.  Antioncogenes and human cancer. , 1993, Annual review of medicine.

[44]  D. Drucker,et al.  Glucagon gene 5'-flanking sequences direct expression of simian virus 40 large T antigen to the intestine, producing carcinoma of the large bowel in transgenic mice. , 1992, The Journal of biological chemistry.