玉米赤霉烯酮对乳腺癌细胞MCF-7增殖和凋亡的影响

目的 观察真菌雌激素玉米赤霉烯酮（ZEA）对人乳腺癌细胞MCF-7增殖和凋亡的影响,并初步探讨其分子生物学作用机制。方法 用噻唑蓝比色法观察ZEA对MCF-7细胞增殖活力流式细胞术观察ZEA对MCF-7细胞增殖活力和细胞周期分布的影响;用凋亡DNA片段检测试剂盒和流式细胞术从不同方面检测ZEA对细胞凋亡的影响;逆转录聚合酶链反应（RT-PCR）和蛋白印迹技术检测ZEA对bcl-2和bax mRNA和蛋白质表达的影响。结果 MCF-7细胞生长为雌激素依赖性：溶剂对照组（外源性雌激素缺乏且内源性雌激素耗尽的条件下）细胞增殖活力为100％,10nmol／L雌二醇组细胞增殖活力为257．6％;另外,以溶剂对照组发生凋亡率为100％来计,10nmol／L雌二醇组细胞凋亡率只有为10．8％。ZEA对MCF-7细胞生物学效应的影响同雌二醇类似：在2～96nmol／L浓度范围内,ZEA可快速恢复MCF-7细胞增殖活力（96nmol／L组细胞增殖活力为对照组的2．4倍）,提高S期细胞分布比例（96nmol／L组S期细胞分布比例为对照组的2．3倍）,降低凋亡百分率（96nmol／L组细胞细胞凋亡率为对照组的23．7％）,并呈现出良好的剂量-效应关系。RT-PCR和蛋白印迹结果分析显示,ZEA能够促进bcl-2 mRNA和蛋白质表达,对bax的表达则表现出抑制作用。结论 同雌激素类似,ZEA可提高MCF-7细胞增殖活力并促进有丝分裂指数;通过对bcl-2和bax表达的调节作用,ZEA可抑制雌激素耗尽所诱导的MCF-7细胞凋亡。

Effects of zearalenone on proliferation and apoptosis in MCF-7 cells

Objective To explore the effects of zearalenone (ZEA) on proliferation and apoptosis in estrogen-dependent human breast cancer MCF-7 cells and the likely underlying molecular mechanisms.Methods Cell viability was determined by MTT assay and cell cycle distribution by cytometry. Apoptosis was detected by Cell Death Detection ELISA and cytometry, respectively. The expressions of bax and bcl-2 were examined using multiple RT-PCR and Western-blot both at mRNA and protein level, respectively.Results The current study confirmed the previous studies that ZEA coule stimulate proliferation in MCF-7 cells with inducing a profound increase in S phase and a modest increase in G_2/M phase that was accompanied by a decrease in G_0/G_1 phase.ZEA could inhibit apoptosis in MCF-7 cells following estrogen ablation at a range of concentrations of 2 nmol/L -96 nmol/L.Western blot and RT-PCR analysis revealed that the anti-apoptotic bcl-2 was upregulated at both protein and mRNA level, together with the downregulation of pro-apoptotic bax.Conclusion ZEA should have possessed comparative estrogenic activity and could promote the progression of MCF-7 cells through the cell cycle by a decreasing in the G_0/G_1 phase and by a significant increasing in S-phase. The pro-proliferative activity of ZEA was due to inhibition of apoptosis through regulation of bax/bcl-2 expression.