Colnot S, Decaens T, Niwa-Kawakita M, Godard C, Hamard G, Kahn A, Giovannini M, Perret C. Liver-targeted disruption of Apc in mice activates beta-catenin signaling and leads to hepatocellular carcinomas.
Proc Natl Acad Sci U S A 2004;
101:17216-21. [PMID:
15563600 PMCID:
PMC535370 DOI:
10.1073/pnas.0404761101]
[Citation(s) in RCA: 242] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Although inappropriate activation of the Wnt/beta-catenin pathway has been implicated in the development of hepatocellular carcinoma (HCC), the role of this signaling in liver carcinogenesis remains unclear. To investigate this issue, we constructed a mutant mouse strain, Apc(lox/lox), in which exon 14 of the tumor-suppressor gene adenomatous polyposis coli (Apc) is flanked by loxP sequences. i.v. injection of adenovirus encoding Cre recombinase (AdCre) at high multiplicity [10(9) plaque-forming units (pfu) per mouse] inactivated the Apc gene in the liver and resulted in marked hepatomegaly, hepatocyte hyperplasia, and rapid mortality. beta-Catenin signaling activation was demonstrated by nuclear and cytoplasmic accumulation of beta-catenin in the hepatocytes and by the induction of beta-catenin target genes (glutamine synthetase, glutamate transporter 1, ornithine aminotransferase, and leukocyte cell-derived chemotaxin 2) in the liver. To test a long-term oncogenic effect, we inoculated mice with lower doses of AdCre (0.5 x 10(9) pfu per mouse), compatible with both survival and persistence of beta-catenin-activated cells. In these conditions, 67% of mice developed HCC. beta-Catenin signaling was strongly activated in these Apc-inactivated HCCs. The HCCs were well, moderately, or poorly differentiated. Indeed, their histological and molecular features mimicked human HCC. Thus, deletion of Apc in the liver provides a valuable model of human HCC, and, in this model, activation of the Wnt/beta-catenin pathway by invalidation of Apc is required for liver tumorigenesis.
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