Kinase activation profile associated with TGF-β-dependent migration of HCC cells: a preclinical study

To identify the molecular mechanisms responsible for tumor cell migration is essential for developing agents that can prevent the relapse or the metastatic spread of hepatocellular carcinoma (HCC). In this study, we investigated the effects of the transforming growth factor-beta receptor I inhibitor LY2109761 on two different human HCC cell lines, in vitro and in vivo. LY2109761 inhibits HCC migration in a dose-dependent manner. This inhibition is associated with the decreased phosphorylation of SMAD-2, FAK and beta 1-integrin, and with increased levels of E-cadherin. By contrast, LY2109761 did not alter the phosphorylation pattern of p38MAPkinase. In a two- and a three-day time-course and in dose-titration experiments, LY2109761 inhibited HCC migration as well as phospho-SMAD-2 and the adhesion proteins. LY2109761 showed the best effect on day 2 at 1 nM and for 3 days at 100 nM concentration. This suggests that maximum effects were sustained for several days and were not dependent on excess concentrations. Finally, in a xenograft model of HCC, LY2109761 strongly inhibits tumor growth, intravasation and metastasis at the aforementioned lower concentrations. In conclusion, inhibition of transforming growth factor-beta (TGF-beta) appears to occur at low concentrations of LY2109761 that displays multiple effects on kinases that control HCC cell migration. These findings may help the design of future clinical trials with inhibitors of TGF-beta.