Dietary compound proanthocyanidins from Chinese bayberry (Myrica rubra Sieb. et Zucc.) leaves inhibit angiogenesis and regulate cell cycle of cisplatin-resistant ovarian cancer cells via targeting Akt pathway

Ovarian cancer is the leading cause of death from gynecological malignancy and natural products have drawn great attention for cancer treatment. Chinese bayberry leaves proanthocyanidin (BLPs) with epigallocatechin-3-O-gallate (EGCG) as its terminal and major extension units is unusual in the plant kingdom. In the present study, BLPs showed strong growth inhibitory effects on cisplatin-resistant A2780/CP70 cells by inhibiting angiogenesis and inducing G1 cell cycle arrest. BLPs reduced the tube formation in HUVECs and attenuated the wound healing ability in A2780/CP70 cells. BLPs further reduced the level of ROS and targeted Akt/mTOR/p70S6K/4E-BP-1 pathway to reduce the expression of HIF-1α and VEGF, and thus inhibited angiogenesis. Furthermore, BLPs induced G1 cell cycle arrest by reducing the expressions of c-Myc, cyclin D1 and CDK4, which was also in accordance with the flow cytometry analysis. Overall, these results indicated that BLPs could be a valuable resource of natural compounds for cancer treatment.