二甲双胍对人肺腺癌A549细胞增殖和凋亡的调控

Effects of antidiabetic drug metformin on human lung adenocarcinoma cell A549 proliferation and apoptosis in vitro

背景与目的:二甲双胍作为一种胰岛素增敏剂被用于Ⅱ型糖尿病的一线治疗。近来的临床研究发现二甲双胍可降低糖尿病患者的肿瘤发生率,提示它可能具有抗肿瘤的作用。本研究观察二甲双胍对人肺腺癌A549细胞增殖及凋亡的影响,并探讨其可能的机制。方法:二甲双胍干预人肺腺癌A549细胞48h后,采用MTT法检测其对细胞增殖的影响,流式细胞术检测细胞凋亡,实时PCR法检测p53、Bcl-2和Bax mRNA的转录情况。结果:经二甲双胍干预48h后,人肺腺癌A549细胞的增殖受到明显抑制,且该抑制作用呈药物浓度依赖性增加。当二甲双胍浓度为0.5、2和8mmol/L时对细胞生长的抑制率分别为(29±5)%、(68±3)%和(84.1±2.6)%。流式细胞术检测提示中、高浓度(2、8mmol/L)二甲双胍可促进A549细胞凋亡;其中,药物作用48h后,8mmol/L组细胞的早期凋亡率为(2.1±0.5)%,中、晚期凋亡率为(9±4)%,均显著高于对照组。二甲双胍干预后细胞凋亡相关基因p53、Bcl-2和BaxmRNA表达均上调,且Bcl-2/Bax比值下调。结论:二甲双胍能显著抑制人肺腺癌A549细胞增殖,促进细胞凋亡增加;其机制可能与上调细胞凋亡相关基因p53的表达及Bcl-2/Bax比值下降有关。

Background and purpose： Metformin is known to be an insulin sensitization agent and is a first line treatment for patients with type 2 diabetes. Recent clinical studies have revealed that metformin treatment has been associated with reduced cancer risk, which indicated that metformin may be a potential anti-neoplastic agent. We investigated the effects of antidiabetic drug metformin on proliferation and apoptosis in human lung adenocarcinoma cell line A549 in vitro and explored the possible underlying mechanisms. Methods： A549 cells were treated with 0.5 mmol/L, 2 mmol/L and 8 mmol/L metformin for 48 hrs. Growth inhibition rates of the cells were measured by MTT assay. Cell apoptosis were detected by flow cytometery（FCM）. Expressions of three genes including p53, Bcl-2 and Bax mRNA in the cells were measured by Real-Time PCR. Results： The proliferation of A549 cells was inhibited by metformin in a dose-dependent manner. The Inhibition rates of metformin at dosage of 0.5 mmol/L, 2 mmol/L and 8 mmol/L group were （29±5）%, （68±3）% and （84.1±2.6）%, respectively. Apoptosis was induced when the cells were treated with moderate to high concentrations of metformin.The percentage of cells in early and late stage of apoptosis was increased from （1.1±0.3）% and （1.78±0.22）% in controlled group to （2.1±0.5）% and （94±4）% in metformin 8 mmol/ L group, respectively. The expressions of p53, Bcl-2 and Bax mRNA were all up-regulated after metformin treatment while the Bcl-2/Bax ratio was significantly decreased. Conclusion： Metformin can inhibit the proliferation of human adenocarcinoma cancer cell line A549 and induce cell apoptosis with moderate to high drug concentrations in vitro, which may partly be attributed to the up-regulation of p53 and down-regulation of the Bcl-2/Bax ratio.