Cisplatin promotes the expression level of PD-L1 in the microenvironment of hepatocellular carcinoma through YAP1.

Hepatocellular carcinoma (HCC) is one of the most lethal malignancies worldwide. However, the immune tolerance limits the effect of chemotherapeutic drugs. Therefore, the mechanism of cisplatin in promoting PD-L1 expression by YAP1 was investigated in the present study, and we found that cisplatin increased the expression level of YAP1 in the mouse liver with H22 cells. Meanwhile, cisplatin improved the expression level of PD-L1, IL-1β and CCL2 in the tumor microenvironment. Further, cisplatin also enhanced the expression level of YAP1 in shYAP1 HepG2215 cells. The expression of PD-L1 was decreased by Verteporfin, YAP1 inhibitor, during the treatment of DEN/TCPOBOP-induced liver cancer in C57BL/6 mice. These results suggested that cisplatin could deteriorate the immunosuppressive microenvironment through increasing PD-L1, CCL2, IL-1β by upregulated YAP1 expression. Therefore, the study suggested that YAP1 blockade destroyed the immunosuppressive microenvironment of cancer to improve the effect of chemotherapy in HCC.