Reversal of multidrug resistance of KBV200 cells by triterpenoids isolated from Poria cocos

Multidrug resistance (MDR) of tumor cells is one of the major problems encountered during cancer chemotherapy. In this paper, we isolated eight triterpenoids from Poria cocos and evaluated their effects on reversing MDR of KBV200 cells. Eight triterpenoids increase significantly vincristine-induced cytotoxicity in drug-resistant KBV200 cells at the concentrations of 12.5 μg/mL and 25 μg/mL. Dehydrotumulosic acid showed the best reversal effect: it increased KBV200 apoptosis induced by vincristine and inhibited P-gp function through enhancing the accumulation and retention of fluorescent P-gp substrate rhodamine 123 in KBV200 cells but had no effect on P-gp expression.