Objective: Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. Studies indicate that aberrant activation of mesenchymal-epithelial transition factor (c-MET) is associated with HCC development. Blocking c-MET signaling shows antitumor efficacy in patients with HCC. Thus, c-MET has been an attractive therapeutic target for HCC. We disclose here for the first time a potent and selective c-MET inhibitor GST-HG161 and show the antitumor efficacy data in preclinical models of HCC.

Method: MHCC97H HCC cell line with c-MET overexpression was used to evaluate the anti-proliferative activity of GST-HG161 in a 120-hour viability assay. Selectivity was evaluated with a panel of cell lines without overexpression of c-MET. Daily oral administration of GST-HG161 doses of 1, 3, 10 and 30mg/kg was used to evaluate its in vivo antitumor efficacy in two animal models of HCC with c-MET overexpression, MHCC97H xenograft (CDX) model and LI-03-0317 xenograft (PDX) model. The c-MET protein levels and gene copy number in LI-03-0317 PDX were assessed by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), respectively. High c-MET expression in LI-03-0317 PDX was determined by the presence of tumor cells with membrane staining of 3+ intensity. Effect of GST-HG161 on c-MET signaling inhibition was assessed by western blot analysis of downstream effector proteins including p-MET, p-AKT and p-ERK.

Result: GST-HG161 displayed potent anti-proliferative activity in MHCC97H HCC cell line (IC50 = 5 nM) while showed little activity in the cell lines without c-MET overexpression. It significantly inhibited tumor growth at tested doses (3, 10 and 30mg/kg) (P<0.05) in both MHCC97H CDX model and LI-03-0317 PDX model. In MHCC97H CDX model, western blot analysis showed that GST-HG161 potently inhibited p-MET and downstream effector proteins p-AKT and p-ERK in the tumor tissue, indicating that the tumor growth inhibition in this model was mediated through inhibition of c-MET.

Conclusion: GST-HG161 is a potent and highly selective c-MET inhibitor. Its excellent antitumor efficacy as shown in

the HCC mouse models provide us with confidence that GST-HG161 has high potential in the clinic for treating patients of HCC with high c-MET activity.

Citation Format: Xiongbin Xu, Gang Li, Lihong Hu, Junguo Hao, Charles Z. Ding, Shuhui Chen. Preclinical evaluation of GST-HG161, a potent and highly selective c-MET inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4792.