title: Menin epigenetically represses Hedgehog signaling in MEN1 tumor syndrome.
abstract: Multiple endocrine neoplasia type 1 (MEN1) is an inherited tumor syndrome that includes susceptibility to pancreatic islet tumors. This syndrome results from mutations in the MEN1 gene, encoding menin. Although menin acts as an oncogenic cofactor for mixed lineage leukemia (MLL) fusion protein-mediated histone H3 lysine 4 methylation, the precise basis for how menin suppresses gene expression and proliferation of pancreatic beta cells remains poorly understood. Here, we show that menin ablation enhances Hedgehog signaling, a proproliferative and oncogenic pathway, in murine pancreatic islets. Menin directly interacts with protein arginine methyltransferase 5 (PRMT5), a negative regulator of gene transcription. Menin recruits PRMT5 to the promoter of the Gas1 gene, a crucial factor for binding of Sonic Hedgehog (Shh) ligand to its receptor PTCH1 and subsequent activation of the Hedgehog signaling pathway, increases repressive histone arginine symmetric dimethylation (H4R3m2s), and suppresses Gas1 expression. Notably, MEN1 disease-related menin mutants have reduced binding to PRMT5, and fail to impart the repressive H4R3m2s mark at the Gas1 promoter, resulting in its elevated expression. Pharmacologic inhibition of Hedgehog signaling significantly reduces proliferation of insulinoma cells, and expression of Hedgehog signaling targets including Ptch1, in MEN1 tumors of mice. These findings uncover a novel link between menin and Hedgehog signaling whereby menin/PRMT5 epigenetically suppresses Hedgehog signaling, revealing it as a target for treating MEN1 tumors.
authors.affiliation: Department of Cancer Biology, Abramson Family Cancer Research Institute, Abramson Cancer Center, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
authors.forename: Buddha
authors.initials: B
authors.lastname: Gurung
authors.forename: Zijie
authors.initials: Z
authors.lastname: Feng
authors.forename: Daniel V
authors.initials: DV
authors.lastname: Iwamoto
authors.forename: Austin
authors.initials: A
authors.lastname: Thiel
authors.forename: Guanghui
authors.initials: G
authors.lastname: Jin
authors.forename: Chen-Min
authors.initials: CM
authors.lastname: Fan
authors.forename: Jessica M Y
authors.initials: JM
authors.lastname: Ng
authors.forename: Tom
authors.initials: T
authors.lastname: Curran
authors.forename: Xianxin
authors.initials: X
authors.lastname: Hua
mesh_terms: D000813:Anilides / Q000494:pharmacology; D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D044127:Epigenesis, Genetic; D058851:GPI-Linked Proteins / Q000235:genetics / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D053823:Hedgehog Proteins / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D006801:Humans; D007515:Islets of Langerhans / Q000378:metabolism / Q000473:pathology; D008745:Methylation; D051379:Mice; D018761:Multiple Endocrine Neoplasia Type 1 / Q000235:genetics* / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011484:Protein-Arginine N-Methyltransferases / Q000235:genetics / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors; D015398:Signal Transduction / Q000187:drug effects; D000072086:Smoothened Receptor
chemical_list: D000813:Anilides; D018797:Cell Cycle Proteins; C096192:GAS1 protein, human; D058851:GPI-Linked Proteins; D053823:Hedgehog Proteins; C538724:HhAntag691; D006657:Histones; C105373:MEN1 protein, human; D011518:Proto-Oncogene Proteins; D011725:Pyridines; D043562:Receptors, G-Protein-Coupled; C491023:SMO protein, human; D000072086:Smoothened Receptor; C400529:PRMT5 protein, human; D011484:Protein-Arginine N-Methyltransferases