Synergistic antitumor effects and mechanism of apigenin and tanshinone ⅡA / 中草药

ABSTRACT

Objective: To evaluate the synergistic anticancer effects of the combination of apigenin (Api) and tanshinone Ⅱ A (Tan IIA), and investigate the mechanisms of pharmacological effects and their potential applications as an anticancer therapy in clinics. Methods: MTT assay were used to determine anticancer effects of the combination of Api and Tan ⅡA on BGC823, MCF7, and SMMC7721 cells. AV-PI dual stain and PI staining method were used for detecting the effect of the two drugs combination on BGC823 cell apoptosis and cell cycle. Expression of p53, BAX/BCL-2, cyclin B1 and D1 proteins were determined by Western blotting. Circular dichroism method and DNA melting point method were explored to detect interaction among the two drugs and DNA. S180 tumor xenograft mice model was used to evaluate the antitumor effects of the two drugs combination. Results: Tan IIA combined with Api exerted synergistic inhibitory effects on the proliferation of BGC823 and other tumor cells with the CI of 0.28. After tumor cell treated by combination of Tan IIA and Api, the tumor cell apoptosis was significantly enhanced and the value of BAX/BCL-2 in cells was up-regulated (P < 0.01); The levels of cyclin B1, D1 protein were changed and cell cycle arrest was increased which mainly blocked in S phase. The interaction among the two drugs and DNA was in two different ways, leading to the curves of thermal denaturation of DNA changed significantly. Furthermore, the combination of Tan IIA and Api showed a stronger inhibitory effect on tumor volume and weight in S180 mice model than monotherapy, which was similar to cyclophosphamide therapy but less side effects. Conclusion Tan IIA combined with Api exerted synergistic antitumor effects. The two drugs interacted with DNA in different ways and aggravated the cell cycle arrest, which were the key mechanisms of their synergistic antitumor effects.