Improving the anti-tumor effect of EGCG in colorectal cancer cells by blocking EGCG-induced YAP activation.

(-)-Epigallocatechin-3-gallate (EGCG) is the primary active ingredient in green tea and has been used for cancer prevention in clinical trials. The anti-tumor effects of EGCG stem from its ability to inhibit the activities of many oncoproteins, such as AKT, VEGFR, STAT3, and mutant p53. However, the clinical efficacy of EGCG is unsatisfactory. How to improve the anti-tumor effects of EGCG is an open question. Here we report that EGCG inhibits the tumor suppressive Hippo signaling pathway and activates downstream YAP in colorectal cancer (CRC) cells. Activation of YAP impedes the anti-tumor effects of EGCG. YAP blockade increases the sensitivity of CRC cells to EGCG treatment.