title: Transposon mutagenesis identifies genes and cellular processes driving epithelial-mesenchymal transition in hepatocellular carcinoma.
abstract: Epithelial-mesenchymal transition (EMT) is thought to contribute to metastasis and chemoresistance in patients with hepatocellular carcinoma (HCC), leading to their poor prognosis. The genes driving EMT in HCC are not yet fully understood, however. Here, we show that mobilization of Sleeping Beauty (SB) transposons in immortalized mouse hepatoblasts induces mesenchymal liver tumors on transplantation to nude mice. These tumors show significant down-regulation of epithelial markers, along with up-regulation of mesenchymal markers and EMT-related transcription factors (EMT-TFs). Sequencing of transposon insertion sites from tumors identified 233 candidate cancer genes (CCGs) that were enriched for genes and cellular processes driving EMT. Subsequent trunk driver analysis identified 23 CCGs that are predicted to function early in tumorigenesis and whose mutation or alteration in patients with HCC is correlated with poor patient survival. Validation of the top trunk drivers identified in the screen, including MET (MET proto-oncogene, receptor tyrosine kinase), GRB2-associated binding protein 1 (GAB1), HECT, UBA, and WWE domain containing 1 (HUWE1), lysine-specific demethylase 6A (KDM6A), and protein-tyrosine phosphatase, nonreceptor-type 12 (PTPN12), showed that deregulation of these genes activates an EMT program in human HCC cells that enhances tumor cell migration. Finally, deregulation of these genes in human HCC was found to confer sorafenib resistance through apoptotic tolerance and reduced proliferation, consistent with recent studies showing that EMT contributes to the chemoresistance of tumor cells. Our unique cell-based transposon mutagenesis screen appears to be an excellent resource for discovering genes involved in EMT in human HCC and potentially for identifying new drug targets.
authors.affiliation: Cancer Research Program, Houston Methodist Research Institute, Houston, TX 77030;
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kodama
authors.affiliation: Cancer Research Program, Houston Methodist Research Institute, Houston, TX 77030;
authors.forename: Justin Y
authors.initials: JY
authors.lastname: Newberg
authors.affiliation: Cancer Research Program, Houston Methodist Research Institute, Houston, TX 77030;
authors.forename: Michiko
authors.initials: M
authors.lastname: Kodama
authors.affiliation: Cancer Research Program, Houston Methodist Research Institute, Houston, TX 77030;
authors.forename: Roberto
authors.initials: R
authors.lastname: Rangel
authors.affiliation: Department of Obstetrics and Gynecology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 9518510, Japan;
authors.forename: Kosuke
authors.initials: K
authors.lastname: Yoshihara
authors.affiliation: Michigan Center for Translational Pathology, Department of Pathology, University of Michigan, Ann Arbor, MI 48109;
authors.forename: Jean C
authors.initials: JC
authors.lastname: Tien
authors.affiliation: Department of Pathology and Immunology, Baylor College of Mecidine and Texas Children's Hospital, Houston, TX 77030.
authors.forename: Pamela H
authors.initials: PH
authors.lastname: Parsons
authors.affiliation: Department of Pathology and Immunology, Baylor College of Mecidine and Texas Children's Hospital, Houston, TX 77030.
authors.forename: Hao
authors.initials: H
authors.lastname: Wu
authors.affiliation: Department of Pathology and Immunology, Baylor College of Mecidine and Texas Children's Hospital, Houston, TX 77030.
authors.forename: Milton J
authors.initials: MJ
authors.lastname: Finegold
authors.affiliation: Cancer Research Program, Houston Methodist Research Institute, Houston, TX 77030;
authors.forename: Neal G
authors.initials: NG
authors.lastname: Copeland
authors.affiliation: Cancer Research Program, Houston Methodist Research Institute, Houston, TX 77030; njenkins2@houstonmethodist.org.
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Jenkins
mesh_terms: D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism; D002465:Cell Movement / Q000235:genetics; D004251:DNA Transposable Elements; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics*; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D008822:Mice, Transgenic; D016296:Mutagenesis; D009363:Neoplasm Proteins / Q000235:genetics; D000090063:Proto-Oncogene Mas
chemical_list: D004251:DNA Transposable Elements; C000715470:MAS1 protein, human; D009363:Neoplasm Proteins; D000090063:Proto-Oncogene Mas
keywords: EMT; HCC; Met; transposon; ubiquitin-mediated proteolysis