A mouse model of cholestasis-associated cholangiocarcinoma and transcription factors involved in progression.

Abstract

BACKGROUND & AIMS:

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: Heping Yang, Tony W H Li, Jian Peng, Xiaoli Tang, Kwang Suk Ko, Meng Xia, Maria-Angeles Aller
• Journal: Gastroenterology (Gastroenterology) Vol. 141 Issue 1 Pg. 378-88, 388.e1-4 (Jul 2011) ISSN: 1528-0012 [Electronic] United States
• PMID: 21440549 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2011 AGA Institute. Published by Elsevier Inc. All rights reserved.

Chemical References

• Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
• Basic Helix-Loop-Helix Transcription Factors
• Ccnd1 protein, mouse
• Hif1a protein, mouse
• Hypoxia-Inducible Factor 1, alpha Subunit
• Lin-28 protein, mouse
• MIRN210 microRNA, mouse
• MIRN34a microRNA, mouse
• MicroRNAs
• Mnt protein, mouse
• Myc protein, mouse
• Proto-Oncogene Proteins c-myc
• RNA-Binding Proteins
• Repressor Proteins
• Transcription Factors
• mirnlet7 microRNA, mouse
• Cyclin D1
• Max protein, mouse
• endothelial PAS domain-containing protein 1
• Diethylnitrosamine

Topics

• Animals
• Basic Helix-Loop-Helix Leucine Zipper Transcription Factors (metabolism)
• Basic Helix-Loop-Helix Transcription Factors (metabolism)
• Bile Duct Neoplasms (etiology, genetics, metabolism, pathology)
• Bile Ducts, Intrahepatic (metabolism, pathology, surgery)
• Cholangiocarcinoma (etiology, genetics, metabolism, pathology)
• Cholestasis (chemically induced, complications, genetics, metabolism, pathology)
• Cyclin D1 (metabolism)
• Diethylnitrosamine
• Disease Models, Animal
• Disease Progression
• Gene Expression Regulation, Neoplastic
• Hyperplasia
• Hypoxia-Inducible Factor 1, alpha Subunit (metabolism)
• Ligation
• Liver (metabolism, pathology)
• Male
• Mice
• Mice, Inbred BALB C
• MicroRNAs (metabolism)
• Proto-Oncogene Proteins c-myc (metabolism)
• RNA Interference
• RNA-Binding Proteins (metabolism)
• Repressor Proteins (metabolism)
• Signal Transduction
• Time Factors
• Transcription Factors (genetics, metabolism)