title: Hedgehog pathway dysregulation contributes to the pathogenesis of human gastrointestinal stromal tumors via GLI-mediated activation of KIT expression.
abstract: Gastrointestinal stromal tumors (GIST) arise within the interstitial cell of Cajal (ICC) lineage due to activating KIT/PDGFRA mutations. Both ICC and GIST possess primary cilia (PC), which coordinate PDGFRA and Hedgehog signaling, regulators of gastrointestinal mesenchymal development. Therefore, we hypothesized that Hedgehog signaling may be altered in human GIST and controls KIT expression. Quantitative RT-PCR, microarrays, and next generation sequencing were used to describe Hedgehog/PC-related genes in purified human ICC and GIST. Genetic and pharmacologic approaches were employed to investigate the effects of GLI manipulation on KIT expression and GIST cell viability. We report that Hedgehog pathway and PC components are expressed in ICC and GIST and subject to dysregulation during GIST oncogenesis, irrespective of KIT/PDGFRA mutation status. Using genomic profiling, 10.2% of 186 GIST studied had potentially deleterious genomic alterations in 5 Hedgehog-related genes analyzed, including in the PTCH1 tumor suppressor (1.6%). Expression of the predominantly repressive GLI isoform, GLI3, was inversely correlated with KIT mRNA levels in GIST cells and non-KIT/non-PDGFRA mutant GIST. Overexpression of the 83-kDa repressive form of GLI3 or small interfering RNA-mediated knockdown of the activating isoforms GLI1/2 reduced KIT mRNA. Treatment with GLI1/2 inhibitors, including arsenic trioxide, significantly increased GLI3 binding to the KIT promoter, decreased KIT expression, and reduced viability in imatinib-sensitive and imatinib-resistant GIST cells. These data offer new evidence that genes necessary for Hedgehog signaling and PC function in ICC are dysregulated in GIST. Hedgehog signaling activates KIT expression irrespective of mutation status, offering a novel approach to treat imatinib-resistant GIST.
authors: Department of Surgery, Division of Surgical Oncology, Moores UCSD Cancer Center, University of California, San Diego, La Jolla, California, USA.
authors: Chih-Min
authors: CM
authors: Tang
authors: Department of Surgery, Division of Surgical Oncology, Moores UCSD Cancer Center, University of California, San Diego, La Jolla, California, USA.
authors: Tracy E
authors: TE
authors: Lee
authors: Department of Physiology and Biomedical Engineering and Gastroenterology Research Unit, Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA.|Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA.
authors: Sabriya A
authors: SA
authors: Syed
authors: Department of Medicine, Division of Hematology/Oncology, Moores UCSD Cancer Center, University of California, San Diego, La Jolla, California, USA.
authors: Adam M
authors: AM
authors: Burgoyne
authors: Department of Surgery, Division of Surgical Oncology, Moores UCSD Cancer Center, University of California, San Diego, La Jolla, California, USA.
authors: Stephanie Y
authors: SY
authors: Leonard
authors: Department of Physiology and Biomedical Engineering and Gastroenterology Research Unit, Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA.
authors: Fei
authors: F
authors: Gao
authors: Department of Surgery, Division of Surgical Oncology, Moores UCSD Cancer Center, University of California, San Diego, La Jolla, California, USA.
authors: Jonathan C
authors: JC
authors: Chan
authors: School of Medicine, University of California, San Diego, La Jolla, California, USA.
authors: Eileen
authors: E
authors: Shi
authors: Foundation Medicine, Inc., Cambridge, Massachusetts, USA.
authors: Juliann
authors: J
authors: Chmielecki
authors: Foundation Medicine, Inc., Cambridge, Massachusetts, USA.
authors: Deborah
authors: D
authors: Morosini
authors: Foundation Medicine, Inc., Cambridge, Massachusetts, USA.
authors: Kai
authors: K
authors: Wang
authors: Foundation Medicine, Inc., Cambridge, Massachusetts, USA.
authors: Jeffrey S
authors: JS
authors: Ross
authors: Department of Surgery, Mayo Clinic, Rochester, Minnesota, USA.
authors: Michael L
authors: ML
authors: Kendrick
authors: Department of Physiology and Biomedical Engineering and Gastroenterology Research Unit, Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA.
authors: Michael R
authors: MR
authors: Bardsley
authors: Department of Surgery, Division of Surgical Oncology, Moores UCSD Cancer Center, University of California, San Diego, La Jolla, California, USA.
authors: Martina De
authors: M
authors: Siena
authors: Department of Molecular, Cell and Cancer Biology, University of Massachusetts, Worchester, Massachusetts, USA.
authors: Junhao
authors: J
authors: Mao
authors: Division of Biomedical Informatics, Moores UCSD Cancer Center, University of California San Diego, La Jolla, California, USA.
authors: Olivier
authors: O
authors: Harismendy
authors: Department of Physiology and Biomedical Engineering and Gastroenterology Research Unit, Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA.|Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors: Tamas
authors: T
authors: Ordog
authors: Department of Surgery, Division of Surgical Oncology, Moores UCSD Cancer Center, University of California, San Diego, La Jolla, California, USA.|School of Medicine, University of California, San Diego, La Jolla, California, USA.
authors: Jason K
authors: JK
authors: Sicklick
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology; D001665:Binding Sites; D045744:Cell Line, Tumor; D002470:Cell Survival; D002923:Cilia / Q000378:metabolism / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm; D005770:Gastrointestinal Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D000068877:Imatinib Mesylate / Q000494:pharmacology; D056885:Interstitial Cells of Cajal / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010087:Oxides / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection; D000071676:Zinc Finger Protein GLI1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000075746:Zinc Finger Protein Gli2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000074290:Zinc Finger Protein Gli3 / Q000235:genetics / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D001152:Arsenicals; C400551:GLI1 protein, human; C082593:GLI2 protein, human; C065683:GLI3 protein, human; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D010087:Oxides; D012333:RNA, Messenger; D000071676:Zinc Finger Protein GLI1; D000075746:Zinc Finger Protein Gli2; D000074290:Zinc Finger Protein Gli3; D000068877:Imatinib Mesylate; D019009:Proto-Oncogene Proteins c-kit; D020796:Receptor, Platelet-Derived Growth Factor alpha; D000077237:Arsenic Trioxide
keywords: GIST; GLI; ICC; arsenic trioxide; imatinib-resistant