姜黄素诱导结肠癌LoVo细胞凋亡的作用及机制研究

Study on functions and mechanism of curcumin in inducing colorectal carcinoma cells LoVo apoptosis

目的:探讨姜黄素促人结肠癌LoVo细胞凋亡的生物学作用及其调控机制。方法:体外培养人结肠癌LoVo细胞,0～20 mg.L-1不同浓度姜黄素处理后,采用MTT比色法测定姜黄素对细胞的增殖抑制作用,利用透射电镜观察细胞的超微结构,采用PI单标流式细胞仪测定细胞周期分布,Annexin V-FITC/PI双标法检测细胞凋亡率;采用RT-PCR检测Bax,Bcl-2,Caspase-3,Bcl-xL mRNA表达水平。结果:MTT检测显示姜黄素能显著抑制人结肠癌LoVo细胞的生长、増殖,呈现浓度和时间效应关系;透射电镜结果显示姜黄素能使LoVo细胞发生形态学改变,呈现典型凋亡细胞特征;流式细胞仪分析显示姜黄素能阻滞细胞周期于S期,诱导细胞发生凋亡。RT-PCR检测显示姜黄素可促进细胞中Bax,Caspase-3 mRNA表达,抑制Bcl-2,Bcl-xL mRNA表达。结论:姜黄素能显著抑制人结肠癌LoVo细胞的增殖并促进其凋亡,这种生物学效应可能与激活Bax表达、抑制Bcl-2和Bcl-xL表达而活化Caspase-3的信号通路有关。

Objective： To discuss the biological function and regulation mechanism of curcumin in promoting human colorectal carcinoma （LoVo） cells apoptosis. Method： Conventional in vitro culture in human colorectal carcinoma cells LoVo, When 80% -90% confluence was reached, cells were treated with curcumin at different concentrations （0-20 mg. L-1 ）. Curcumin＇s effect on cell pro- liferation level was examined by MTT colorimetry. The ultrastructure of curcumin-treated LoVo cells were observed with transmission electron microscope （TEM）. The amount of PI-positive LoVo cells after the curcumin treatment were determined by flow cytometry. The cell apoptosis rate was detected by Annexin V-FITC/PI double staining. The mRNA level of Bax, Bcl-2, Caspase-3 and Bcl-xL were tested by means of RT-PCR. Result： MTT test indicates curcumin could inhibite the growth and proliferation of LoVo cells in a time- and concentration-dependent manner. TEM examination showed that curcumin can make LoVo cell morphological changes, show- ing the typical characteristics of apoptotic cells. Flow cytometry instrument analysis showed that curcumin can arrest cell cycle at S phase, and induce apoptosis of LoVo cells. RT-PCR test showed that curcumin can activate the expression of Bax and Caspase-3, in- hibit the expression of Bcl-2 and Bcl-xL at the mRNA level. Conclusion： Curcumin can significantly inhibit the proliferation and in- duce the apoptosis of human colorectal carcinoma cells LoVo. Such biological effect may be associated with activating Caspase-3 signal channel by activating Bax expression and inhibiting Bcl-2 and Bcl-xL expression. This study lays an important foundation for further discussing the mechanism of curcumin in inducing human colorectal carcinoma LoVo apoptosis.