Smad7 enhances TGF-β dependent apoptosis in hepatocytes

One of the major tumorsuppressor functions of TGF-β is negative control of cell growth. Therefore, mutational inactivation or dysregulated expression of components in its signaling pathway have been associated with cancer. We found overexpression of Smad7 in 85% of hepatocellular carcinoma (HCC) samples. Smad7 is an intracellular antagonist of TGF-β and its up-regulation may cause escape from the antiproliferative effects of TGF-β. In hepatocytes, TGF-β provides its growth inhibitory effects at least partially by apoptosis. To investigate Smad7 function in a possible disorder of cell proliferation control in HCC…