表没食子儿茶素没食子酸酯联合叶酸杀伤胃癌细胞的实验研究

背景：表没食子儿茶素没食子酸酯（EGCG）具有抗肿瘤作用，对不同胃肠道肿瘤细胞系具有不同程度的、呈剂量依赖的杀伤作用。叶酸是一种水溶性维生素，叶酸缺乏可增加肿瘤的发生率，影响肿瘤细胞凋亡。目的：研究EGCG联合叶酸对胃癌细胞杀伤作用的影响。方法：以甲基噻唑基四唑（MTT）比色法检测EGCG联合叶酸对胃癌细胞系MKN45、SGC7901、MKN28的杀伤作用。流式细胞仪测定两者对MKN45细胞周期的影响。结果：EGCG联合叶酸较EGCG单独作用对MKN45、SGC7901、MKN28细胞的杀伤作用增强，EGCG半数抑制浓度（IC50）分别降低28．4％、51．9％和40．0％。3种浓度的EGCG联合叶酸作用48h后，MKN45细胞的细胞周期分布与对照组和EGCG组相比无明显变化（P〉0．05）。结论：EGCG联合叶酸较EGCG单独作用对胃癌细胞的杀伤作用增强，但对MKN45的细胞周期分布无明显影响。

Experimental Study on the Killing Effect of Epigallocatechin-3-gallate Combined with Folic Acid on Gastric Cancer Cells

Background: The inhibitory action of epigallocatechin-3-gallate (EGCG) against cancer formation has been demonstrated. For distinct gastrointestinal tract cancer cell lines, EGCG has different dose-dependent killing effects. Folic acid is a soluble vitamin and its deficiency may increase tumor incidence and influence tumor cell apoptosis. Aims: To study the influence of folic acid on the killing effect of EGCG in gastric cancer cells. Methods: The killing effects of EGCG combined with folic acid on three different gastric cancer cell lines (MKN45, SGC7901 and MKN28) were detected by methyl thiazolyl tetrazolium (MTT) analysis. The cell cycle distribution of MKN45 cell line was measured by flow cytometry. Results: The killing effect of EGCG combined with folic acid on the three gastric cancer cell lines was stronger than that of EGCG alone. A decrease of 28.4%, 51.9% and 40.0% of 50% inhibitory concentrations (IC50) was observed in three gastric cancer cell lines. There were no apparent changes in the cell cycle distribution of MKN45 cells after 48 hours incubation with three different concentrations of EGCG combined with folic acid compared with the control group and EGCG group (P>0.05). Conclusions: The killing effect of EGCG combined with folic acid on the gastric cancer cells was stronger than that of EGCG alone, but the combination has no obvious influence on cell cycle distribution of MKN45 cancer cell line.