Abstract
Cisplatin is one of the most potent chemotherapy drugs widely used for cancer treatment. However, due to resistance and toxicity, the application of cisplatin for the treatment of hepatocellular carcinoma (HCC) is limited. Our previous study has shown that granulin A (GRN A), an anticancer peptide, is able to interact with enolase1 (ENO1) and inhibit the growth of HCC in vitro. In the present study, we studied the synergistic effect of the combination of cisplatin and GRN A for the inhibitory effect on HCC. An 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and Chou-Talalay approaches revealed that the combination of GRN A and cisplatin displayed potent synergistic effect. The colony formation and cell viability of HCC cells were inhibited significantly in cells treated with the combination of cisplatin and GRN A, compared with cells treated with cisplatin or GRN A alone. Overexpression of ENO1 diminished the synergistic effect of GRN A and cisplatin in HCC cells. The combination of the two drugs exhibited a more obvious inhibitory effect on cancer cell apoptosis, as analyzed by the cytometry flow, mitochondrial membrane potential (MMP) and western blot analysis. An in vivo study confirmed that the combined use of the two drugs displayed more potent antitumor activity compared to mice treated with cisplatin and GRN A alone; the inhibitory rate of tumor growth was 65.46% and 68.94%, respectively, in mice treated with GRN A and cisplatin. However, the inhibitory rate increased to 86.63% in mice treated with the combination of the two drugs. This study provides evidence that the combination of GRN A and cisplatin is able to sensitize the liver cancer to cisplatin, and that targeting ENO1 is a promising approach for enhancing the antitumor activity of cisplatin.