Synergistic effect of farnesyl transferase inhibitor lonafarnib combined with chemotherapeutic agents against the growth of hepatocellular carcinoma cells.

Hepatocellular carcinoma (HCC) is a common and deadly cancer worldwide and is often refractory to chemotherapy due to the development of multidrug resistance. Lonafarnib is an orally active and potent non-peptidomimetic inhibitor of farnesyl transferase. Here, using HCC cell models, we demonstrated that lonafarnib inhibited tumor proliferation and reduced the activity of mitogen-activated protein kinases pathways. In addition, lonafarnib caused G1 to S phase arrest through the downregulation of Cyclin D1, CDK6 and SKP2, while it induced cellular apoptosis by promoting the cleavage and activation of Caspase-3 and PARP. When combined with doxorubicin and sorafenib, lonafarnib was able to increase the sensitivity of HCC cells to chemotherapy. Furthermore, we also constructed ABCB1-overexpressing HCC cells and found that lonafarnib decreased chemoresistance by inhibiting ABCB1-mediated drug efflux activity. These results suggest that lonafarnib may be a promising synergistic agent for improving the treatment of drug-resistant HCC.