桦褐孔菌醇对人宫颈癌HeLa细胞凋亡和细胞周期的影响

Effects of Inotodiol on Apoptosis and Cell Cycle of HeLa Cells in Human Cervical Cancer

目的探讨桦褐孔菌醇(inotodiol)对人宫颈癌HeLa细胞诱导凋亡和细胞周期分布的影响及其可能机制。方法不同浓度桦褐孔菌醇与人宫颈癌HeLa细胞共同培养后,采用流式细胞技术检测HeLa细胞周期分布及凋亡率的变化;通过免疫细胞化学法检测cyclinE、p27及bax、bcl-2表达的变化。结果桦褐孔菌醇作用人宫颈癌HeLa细胞后,流式细胞检测显示SubG1峰(细胞凋亡)出现,随桦褐孔菌醇浓度增加和处理时间延长,细胞凋亡率明显增高,且呈时间依赖性关系(r=1.0,P<0.01),S期和G2/M期细胞数显著下降。免疫细胞化学结果显示,cyclinE、bcl-2表达显著降低,p27、bax表达显著增加,与对照组相比均有统计学差异(P<0.05)。结论桦褐孔菌提取物桦褐孔菌醇通过诱导细胞凋亡和G1期阻滞发挥对宫颈癌HeLa细胞的抑制作用,其机制可能与上调bax和下调bcl-2蛋白表达促进细胞凋亡,下调cyclinE和上调负调控因子p27的表达影响细胞周期有关,此结果进一步表明了桦褐孔菌在宫颈癌临床治疗方面的潜在价值。

OBJECTIVE To explore the effects of inotodiol on apoptosis and cell cycle of human cervical cancer HeLa cells and investigate the underlying molecular mechanism. METHODS HeLa ceils were treated with different concentrations of inotodiol. Flow cytometry （FCM） was employed for cell cycle analysis and cell apoptosis. The expressions of cyclinE, p27, bax and bcl-2 were detected by immunocytochemistry. RESULTS The Sub-G1 peak （apoptotic cells） of HeLa ceils were detected after treatment with inotodiol. Apoptosis rate was raised up with higher concentration and longer incubation time, and the effect was in a time-dependent manner （ r = 1.0 ,P 〈 0.01 ） , together with the percentage of S phase and G2/M phase decreased significantly. Immunocytochemistry assay showed that the expression of cyclin E and bcl-2 in the treated cells significantly decreased, while the expression of p27 and bax obviously increased, compared with the control group （P 〈 0.05）. CONCLUSION Inotodiol isolated from Inonotus obliquus induced apoptosis and cell cycle arrest at G1 phase in vitro. The mechanisms may be related to promoting apoptosis through increasing the expression of bax and cutting bcl-2 and affecting the cell cycle by down-regulation the expression of cyclin E and up-regulation of p27. The results further indicate the potential values of inotodiol for the treatment of human cervi- cal cancer.