p38MAPK在地塞米松诱导的人乳腺癌MCF-7细胞系凋亡中的作用

目的 研究地塞米松对人乳腺癌MCF-7细胞株增殖及凋亡的影响,并初步探讨其作用机制.方法 MTT方法检测细胞增殖,流式细胞技术检测细胞凋亡,免疫细胞化学方法、RT-PCR技术检测地塞米松干预前、后细胞中p38MAPK蛋白及基因的表达.结果 分别用不同浓度的地塞米松作用于MCF-7细胞,作用3～5 d时,各种浓度下细胞增殖均明显受抑制,且与药物作用浓度及作用时间呈正相关,并以作用4 d时MCF-7表现出来的增殖抑制最为明显.地塞米松作用于MCF-7细胞后,可见细胞发生凋亡形态改变增多.流式细胞仪检测示地塞米松作用3～5 d后三组细胞凋亡率均较对照组升高,以10-6mol/L浓度作用4 d时凋亡率可达31.85％,与对照组的14.63％相比有明显升高,升高2倍以上,与其他干预组相比,差异有统计学意义(P＜0.05).细胞免疫染色检测结果显示,p38MAPK在MCF-7胞质、胞核均有表达,通过对染色结果进行分析发现,Dex干预后,MCF-7中p38MAPK蛋白表达升高,尤以10-6 mol/L浓度作用时最为明显(P＜0.05).对干预后细胞提取RNA行半定量PCR检测,见目的基因条带清晰,与Marker各条带相比与扩增长度(184 bp)较接近,经灰度分析可得,MCF-7细胞在予以Dex处理后,p38基因表达较对照组明显升高,尤以10-6mol/L浓度时最明显,与其他干预组相比,差异有统计学意义(P＜0.05).结论 地塞米松可抑制人乳腺癌MCF-7细胞增殖,并诱导其凋亡,其作用机制可能与促进p38基因表达有关.

Expression of p38MAPK in human MCF-7 breast cancer cells treated by dexamethasone

Objective To investigate the effect of Dexamethasone (Dex) on the proliferation and apoptosis of human breast cancer cell line MCF-7.Methods Under different Dex concentrations,the human breast cancer cell line MCF-7 cells were observed by inverted microscope;the growth inhibitory rates were detected by MTT test;and apoptosis was determined by Annexin V-FITC staining flow cytometry(FCM);the expression of p38MAPK protein was detected by immunocytochemistry;and the expression of p38 gene was detected by semi-quantitative PCR.Results Dex could significantly inhibit the growth of MCF-7 in a dose and time dependent manner,and 10-6 mol/L of Dex could induce apoptosis obviously.The expression of p38 mRNA and p38 MAPK is significantly increased in MCF-7 when treated by Dex.Conclusions Dexamethasone can inhibit cell proliferation,induce apoptosis in MCF-7 cell,Which is time and concentration-dependent,with an up-regulating expression of p38.