Targeting survivin with Tanshinone IIA inhibits tumor growth and overcomes chemoresistance in colorectal cancer.

The inhibitor of apoptosis protein survivin has a critical regulatory role in carcinogenesis and treatment tolerance in colorectal cancer (CRC). However, the targeted drugs for survivin protein are extremely limited. In the present research, we discovered that Tanshinone IIA (Tan IIA) played a dual regulatory role in inhibiting tumorigenesis and reversing 5-Fu tolerance via modulating the expression and phosphorylation of survivin in CRC cells. Mechanistically, Tan IIA suppressed the Akt/WEE1/CDK1 signaling pathway, which led to the downregulation of survivin Thr34 phosphorylation and destruction of the interaction between USP1 and survivin to promote survivin ubiquitination and degradation. Furthermore, Tan IIA significantly facilitated chemoresistant CRC cells to 5-Fu sensitivity. These results revealed that Tan IIA possessed a strong antitumor activity against CRC cells and could act as an up-and-coming agent for treating CRC and overcoming chemotherapy resistance.