EGCG对大肠癌细胞系LoVo细胞增殖的影响及其机制

Effect of EGCG on Proliferation of Human Colorectal Cancer Lovo Cells and Its Mechanism

目的:探讨EGCG对大肠癌细胞系LoVo细胞增殖的影响及其可能的作用机制。方法:体外培养的LoVo细胞,用不同浓度EGCG处理24、48、72 h,MTT法测定其对LoVo细胞增殖的影响;倒置显微镜下观察细胞的形态学变化;EGCG(浓度分别为10、40、80μg/m L)处理LoVo细胞48 h后,分别采用流式细胞仪检测细胞凋亡、分光光度计检测Casepase-3相对活性、RT-PCR和western blot法检测环氧合酶2(COX-2)基因表达情况。结果:EGCG(浓度10~80μg/m L)能显著抑制LoVo细胞增殖,呈剂量和时间依赖性;倒置显微镜下可观察到典型的细胞凋亡形态;EGCG(浓度分别为10、40、80μg/m L)作用LoVo细胞48 h后,细胞凋亡率分别为12.5%、23.3%、35.4%,对照组凋亡率为3.4%;Casepase-3相对活性显著增加;COX-2的表达降低,呈剂量依赖性。结论:EGCG能抑制LoVo细胞的增殖并诱导其凋亡,其作用机制可能与增加细胞Casepase-3活性及下调COX-2基因的表达有关。EGCG有望成为代替NSAIDs或COX-2特异性抑制剂用于大肠癌防治。

Objective： To investigate the effect of EGCG on the proliferation of colorectal cancer line LoVo cells and discuss its possible mechanisms. Methods ： LoVo cells were cultured in vitro. After treatment by EGCG at different concentrations respectively at different time points, the cell survival was determined by the MTT method. The changes of cell morphology were observed by inverted microscope. Apoptosis was detected by flow cytometry. The relative activity of caspase-3 was monitored by spectrophotometer. Reverse transcription-polymerase chain reaction （ RT-PCR ） and Western blot were used for COX-2 mRNA and protein analysis respectively. Results ： From the data of MTF, the cell proliferation of human colorectal cancer LoVo cells was inhibited by EGCG in a dose-dependent and time-dependent manner. Typical apoptosis morphology of LoVo ceils was observed by inverted microscope. Flow cytometry assays showed that EGCG s^gn＇i^ficantly induced apopt0sis in LoVo cells. After treated with EGCG 10,40,80 p~ g/ mL, the apoptosis rate of Lovo cells was 12.5% , 23.3% and 35.4% respectively, which showed an obvious concentration-effect relationship. The relative activity of caspase-3 of EGCG group RT-PCR. The data of RT-PCR and Western blot showed that EGCG down-regulated COX-2 in a dose-dependent manner in LoVo ceils. Conclusion ： EGCG can inhibit the proliferation of LoVo cells and induce apoptosis, and the mechanism of EGCG on apoptosis may be related to the down regulation of COX-2 expression and the increase of relative activity of caspase-3. We expect that EGCG may replace nonsteroidal anti-inflammatory drugs or selective COX-2 inhibitors in the prevention and treatment of colorectal cancer.