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[摘要]
目的 研究猪苓酮A对雌激素受体(ER)阳性或阴性人乳腺癌细胞的凋亡作用及其可能的作用机制。方法 选择2株ER阳性人乳腺癌细胞(MCF-7细胞、BT474细胞)和1株ER阴性人乳腺癌细胞(MDA-MB-453细胞),用不同浓度的猪苓酮A分别处理24 h,或以50 μmol/L的猪苓酮A分别处理6、12、24、48 h后,分别采用噻唑蓝(MTT)法测定3株乳腺癌细胞的增殖情况;采用流式细胞仪检测细胞凋亡和细胞周期;采用Western blottig法检测与细胞凋亡密切相关的Bcl-2家族蛋白表达情况。结果 猪苓酮A可以时间和剂量依赖性地抑制ER阴性MDA-MB-453细胞的增殖;而对于ER阳性MCF-7、BT474细胞增殖均无明显影响;细胞周期检测显示猪苓酮A可以使MDA-MB-453细胞的生长阻滞在G1或G2/M期;50 μmol/L猪苓酮A作用于MDA-MB-453细胞24 h后,细胞出现明显凋亡,而MCF-7、BT474细胞则没有出现明显凋亡;Western blotting检测发现50 μmol/L猪苓酮A处理组ER阴性MDA-MB-453细胞中促凋亡蛋白Bax、Bad表达量升高,而抗凋亡蛋白Bcl-2、Bcl-w表达量降低。结论 猪苓酮A能抑制ER阴性乳腺癌细胞的增殖并诱导其凋亡,其作用机制与调控Bcl-2家族蛋白的表达量有关。
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[Abstract]
Objective To explore the apoptotic effect of polyporusterone A on estrogen receptor (ER)-positive and ER-negative human breast cancer cells and the possible mechanism. Methods Three human breast cancer cell lines (MDA-MB-453, MCF-7, and BT474) were chosen in this study. MTT assay was performed to measure the relative cell viabilities. Flow cytometry was used to analyze the apoptosis and cell cycle. Western blot analysis was used to determine the expression levels of Bcl-2 family proteins. Results Cell proliferation of ER-negative human breast cancer cells was significantly inhibited by polyporusterone A in a dose-and time-dependent manner, while no significant effect was observed on the proliferation of strogen receptor (ER)-positive human breast cancer MCF-7 and BT474 cells. Moreover, polyporusterone A could reversibly arrest the MDA-MB-253 cells in G1 or G2/M phase. Flow cytometry results showed that 50 μmol/L polyporusterone A induced MDA-MB-253 cells apoptosis after treatment for 24 h, while no apoptosis occurred in MCF-7 and BT474 cell lines. Western blot results showed that 50 μmol/L polyporusterone A up-regulated the protein expression of Bad and Bax, but down-regulated the expression of Bcl-2 and Bcl-w protein. Conclusion Polyporusterone A can inhibit the proliferation of ER-negative breast cancer cells and promote apoptosis, which may be associated with the regulation of the expression of Bcl-2 family proteins.
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