Hepatocellular carcinoma (HCC) is among the leading causes of cancer-related death worldwide, and the development of new treatment regimens is urgently needed to improve therapeutic approach. In our study, we found that the combination of a Met inhibitor, cabozantinib, and a novel FAK inhibitor, CT-707, exerted synergistic anti-tumor effects against HCC in vitro and in vivo. Interestingly, further studies showed that therapeutic concentrations of cabozantinib increased the phosphorylation of FAK, which might attenuate the anti-tumor activity of cabozantinib. The simultaneous exposure to CT-707 effectively inhibited the activation of FAK that was induced by cabozantinib, which contributes to the synergistic effect of the combination. Furthermore, cabozantinib increased the mRNA and protein levels of integrin α5, which is a canonical upstream of FAK, and the introduction of cilengitide to block integrin function could abrogate FAK activation by cabozantinib, indicating that cabozantinib up-regulated the phosphorylation of FAK in an integrin-dependent manner. Similar synergy was also observed on PHA-665752, another selective MET inhibitor, indicating that this observation might be a common characteristic of MET-targeting strategies. Our findings not only favor the development of the novel FAK inhibitor, CT-707, as a therapeutic agent against HCC but also provide a new strategy of combining MET and FAK inhibitors to potentiate the anticancer activities of these two types of agents for treating HCC patients.
- Received May 12, 2016.
- Revision received August 10, 2016.
- Accepted August 24, 2016.
- Copyright ©2016, American Association for Cancer Research.