Molecular mechanisms of liver carcinogenesis in the Mdr2-knockout mice

Mark Katzenellenbogen, Lina Mizrahi, Orit Pappo, Naama Klopstock, Devorah Olam, Jasmine Jacob-Hirsch, Ninette Amariglio, Gideon Rechavi, Eytan Domany, Eithan Galun, Daniel Goldenberg

Research output: Contribution to journalArticlepeer-review

95 Scopus citations

Abstract

Mouse models of hepatocellular carcinoma (HCC) simulate specific subgroups of human HCC. We investigated hepatocarcinogenesis in Mdr2-knockout (Mdr2-KO) mice, a model of inflammation-associated HCC, using gene expression profiling and immunohistochemical analyses. Gene expression profiling showed that although Mdr2-KO mice differ from other published murine HCC models, they share several important deregulated pathways and many coordinately differentially expressed genes with human HCC data sets. Analysis of genome positions of differentially expressed genes in liver tumors revealed a prolonged region of down-regulated genes on murine chromosome 8 in three of the six analyzed tumor samples. This region is syntenic to human chromosomal regions that are frequently deleted in human HCC and harbor multiple tumor suppressor genes. Real-time reverse transcription-PCR analysis of 16 tumor samples confirmed down-regulation of several tumor suppressors in most tumors. We show that in the aged Mdr2-KO mice, cyclin D1 nuclear level is increased in dysplastic hepatocytes that do not form nodules; however, it is decreased in most dysplastic nodules and in liver tumors. We found that this decrease is mostly at the protein, rather than the mRNA, level. These findings raise the question on the role of cyclin D1 at early stages of hepatocarcinogenesis in the Mdr2-KO HCC model. Furthermore, we show that most liver tumors in Mdr2-KO mice were characterized by the absence of β-catenin activation. In conclusion, the Mdr2-KO mouse may serve as a model for β-catenin-negative subgroup of human HCCs characterized by low nuclear cyclin D1 levels in tumor cells and by down-regulation of multiple tumor suppressor genes.

Original languageEnglish
Pages (from-to)1159-1170
Number of pages12
JournalMolecular Cancer Research
Volume5
Issue number11
DOIs
StatePublished - 1 Nov 2007
Externally publishedYes

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