胡椒碱与棉酚联用对前列腺癌DU145细胞生长抑制的协同作用

Synergistic inhibition of growth of prostate cancer DU145 cells by combined piperine and gossypol treatment

目的研究胡椒碱与棉酚联合用药对激素非依赖型前列腺癌DU145细胞生长的抑制作用及其机制。方法 MTS比色法检测细胞活性;流式细胞术分析细胞周期;免疫印迹法检测细胞周期相关蛋白以及CYP3A4的表达。结果胡椒碱本身的细胞毒性较小,但与棉酚联用时,表现出协同作用。棉酚对细胞的半数抑制浓度IC50由单用时的21.00μmol·L-1下降到联合用药时的8.07μmol·L-1;两药相互作用指数CDI<1。胡椒碱与棉酚联合用药,可引起细胞G0/G1期阻滞和亚二倍体峰(凋亡峰)增加;同时上调细胞周期抑制蛋白p21Cip1的表达,并下调Cyclin D1、Cyclin A、CyclinB1以及药物代谢酶CYP3A4的表达。结论胡椒碱与棉酚联用,可能是通过诱导细胞周期阻滞,增强凋亡以及抑制CYP3A4药物代谢酶活性,发挥其协同抗前列腺癌作用。

Aim To investigate the effect of combined piperine and gossypol in inhibition of the growth of an- drogen-independent prostate cancer DU145 cells and e- lucidate the underlying mechanism. Methods MTS assay was adopted to measure the cell viability. Cell cycle distribution was analyzed by flow cytometry. Western blotting was used to determine the expression of cell cycle related proteins and CYP3A4. Results Piperine was relatively low toxic to DU145 cells, whereas when it was used in combination with gossypol, the IC50 of gossypol was decreased from 21.00μmol·L-1 to 8.07 μmol·L-1. The coefficient of drug interaction was less than 1, demonstrating that piperine plus gossypol had a synergistic effect on inhibition of the growth of DU145 cells. The combined drugs also significantly arrested cells at Go/G, phase, and increased sub-G0/G1 peak （apoptotic peak）. Mo- reover, the combined piperine and gossypol also results in an increased level of p21ci~ expression and de- creased expression levels of Cyclin D1, Cyclin A, Cyc- lin B1 and drug-metabolic enzyme CYP3A4. Conclu- sion The combination of piperine and gossypol results in synergistic inhibition of DU145 cell growth through induction of cell cycle arrest, increase of cell apoptosis and inhibition of CYP3A4 activity.