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TGF‐β inactivation and TGF‐α overexpression cooperate in an in vivo mouse model to induce hepatocellular carcinoma that recapitulates molecular features of human liver cancer
Author(s) -
Baek Ji Yeon,
Morris Shelli M.,
Campbell Jean,
Fausto Nelson,
Yeh Matthew M.,
Grady William M.
Publication year - 2010
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.25127
Subject(s) - tgf alpha , transforming growth factor , cancer research , biology , hepatocellular carcinoma , signal transduction , endoglin , in vivo , tgf beta receptor 2 , liver cancer , r smad , cancer , medicine , endocrinology , epidermal growth factor receptor , microbiology and biotechnology , stem cell , cd34
Hepatocellular carcinoma (HCC) results from the cumulative effects of deregulated tumor suppressor genes and oncogenes. The tumor suppressor and oncogenes commonly affected include growth factors, receptors and their downstream signaling pathway components. The overexpression of transforming growth factor alpha (TGF‐α) and the inhibition of TGF‐β signaling are especially common in human liver cancer. Thus, we assessed whether TGF‐α overexpression and TGF‐β signaling inactivation cooperate in hepatocarcinogenesis using an in vivo mouse model, MT1/TGFa;AlbCre/Tgfbr2 flx/flx mice (“ TGFa;Tgfbr2 hepko ”), which overexpresses TGF‐α and lacks a TGF‐β receptor in the liver. TGF‐β signaling inactivation did not alter the frequency or number of cancers in mice with overexpression of TGF‐α. However, the tumors in the TGFa;Tgfbr2 hepko mice displayed increased proliferation and increased cdk2, cyclin E and cyclin A expression as well as decreased Cdkn1a/p21 expression compared to normal liver and compared to the cancers arising in the TGF‐α overexpressing mice with intact TGF‐β receptors. Increased phosphorylated ERK1/2 expression was also present in the tumors from the TGFa;Tgfbr2 hepko mice and correlated with downregulated Raf kinase inhibitor protein expression, which is a common molecular event in human HCC. Thus, TGF‐β signaling inactivation appears to cooperate with TGF‐α in vivo to promote the formation of liver cancer that recapitulates molecular features of human HCC.