title: A mouse model of cholestasis-associated cholangiocarcinoma and transcription factors involved in progression.
abstract: OBJECTIVE
  Cholestasis contributes to hepatocellular injury and promotes liver carcinogenesis. We created a mouse model of chronic cholestasis to study its effects on progression of cholangiocarcinoma and the oncogenes involved.
  
  
  METHODS
  To induce chronic cholestasis, Balb/c mice were given 2 weekly intraperitoneal injections of diethylnitrosamine (DEN); 2 weeks later, some mice also received left and median bile duct ligation (LMBDL) and, then 1 week later, were fed DEN, in corn oil, weekly by oral gavage (DLD). Liver samples were analyzed by immunohistochemical and biochemical assays; expression of Mnt and c-Myc was reduced by injection of small inhibitor RNAs.
  
  
  RESULTS
  Chronic cholestasis was induced by DLD and accelerated progression of cholangiocarcinoma, compared with mice given only DEN. Cystic hyperplasias, cystic atypical hyperplasias, cholangiomas, and cholangiocarcinoma developed in the DLD group at weeks 8, 12, 16, and 28, respectively. LMBDL repressed expression of microRNA (miR)-34a and let-7a, up-regulating Lin-28B, hypoxia-inducible factor (HIF)-1α, HIF-2α, and miR-210. Up-regulation of Lin-28B might inhibit let-7a, which is associated with development of cystic hyperplasias, cystic atypical hyperplasias, cholangiomas, and cholangiocarcinoma. Knockdown of c-Myc reduced progression of cholangiocarcinoma, whereas knockdown of Mnt accelerated its progression. Down-regulation of miR-34a expression might up-regulate c-Myc. The up-regulation of miR-210 via HIF-2α was involved in down-regulation of Mnt. Activation of the miR-34a-c-Myc and HIF-2α-miR-210-Mnt pathways caused c-Myc to bind the E-box element of cyclin D1, instead of Mnt, resulting in cyclin D1 up-regulation.
  
  
  CONCLUSIONS
  DLD induction of chronic cholestasis accelerated progression of cholangiocarcinoma, which is mediated by down-regulation of miR-34a, up-regulation miR-210, and replacement of Mnt by c-Myc in binding to cyclin D1.
authors: Division of Gastroenterology and Liver Diseases, USC Research Center for Liver Diseases, Department of Medicine, Keck School of Medicine USC, Los Angeles, CA 90033, USA. heping@usc.edu
authors: Heping
authors: H
authors: Yang
authors: Tony W H
authors: TW
authors: Li
authors: Jian
authors: J
authors: Peng
authors: Xiaoli
authors: X
authors: Tang
authors: Kwang Suk
authors: KS
authors: Ko
authors: Meng
authors: M
authors: Xia
authors: Maria-Angeles
authors: MA
authors: Aller
mesh_terms: D000818:Animals; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism; D001650:Bile Duct Neoplasms / Q000209:etiology* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D001653:Bile Ducts, Intrahepatic / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D018281:Cholangiocarcinoma / Q000209:etiology* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002779:Cholestasis / Q000139:chemically induced / Q000150:complications* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D019938:Cyclin D1 / Q000378:metabolism; D004052:Diethylnitrosamine; D004195:Disease Models, Animal; D018450:Disease Progression; D015972:Gene Expression Regulation, Neoplastic; D006965:Hyperplasia; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D008026:Ligation; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D035683:MicroRNAs / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D034622:RNA Interference; D016601:RNA-Binding Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D019938:Cyclin D1; D004052:Diethylnitrosamine; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D035683:MicroRNAs; D016271:Proto-Oncogene Proteins c-myc; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D000099162:Endothelial PAS Domain-Containing Protein 1; C530105:Ccnd1 protein, mouse; C497443:Hif1a protein, mouse; C488352:Lin-28 protein, mouse; C549325:MIRN210 microRNA, mouse; C551848:MIRN34a microRNA, mouse; C484561:Mnt protein, mouse; C489428:Myc protein, mouse; C542687:mirnlet7 microRNA, mouse; C068422:Max protein, mouse