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目的:探讨Smad4特异性小分子干扰RNA(siRNA)对乳腺癌MDA-MB-231细胞侵袭力及MMP-9表达的影响。方法:构建Smad4 siRNA,将细胞分为空白对照组,Smad4 siRNA转染组,TGF-β处理组,Smad4 siRNA转染+TGF-β处理组。首先用Western blot法检测转染Smad4 siRNA后细胞中Smad4蛋白的表达,以及用荧光素酶报告基因法检测TGF-β处理后细胞Smad结合元件(4xSBE)的活性;然后用Transwell小室模型和Western blot法检测各组细胞的黏附侵袭能力以及基质金属蛋白酶9(MMP-9)蛋白的表达水平。结果:转染Smad4 siRNA后,乳腺癌细胞的Smad4蛋白表达及其TGF-β诱导的4xSBE活性增强均被明显抑制(均P<0.05);与对照组细胞比较,细胞经TGF-β刺激后的侵袭能力及MMP-9的表达量均明显增加(均P<0.05),但预先转染Smad4 siRNA的细胞的上述TGF-β刺激作用被明显抑制(均P<0.05),单纯Smad4 siRNA转染对细胞的侵袭能力及MMP-9的表达量无明显影响。结论:Smad4 siRNA能减弱TGF-β诱导的MDA-MB-231细胞的侵袭能力,该作用可能与其抑制MMP-9的表达有关。
Objective: To investigate the effect of Smad4-specific small interfering RNA (siRNA) on invasiveness and MMP-9 expression in breast cancer MDA-MB-231 cells. Methods: Smad4 siRNA was constructed and divided into blank control group, Smad4 siRNA transfection group, TGF-β treatment group and Smad4 siRNA transfection + TGF-β treatment group. The expression of Smad4 protein in transfected Smad4 siRNA was detected by Western blot and the activity of Smad-binding element (4xSBE) in TGF-β treated cells was detected by luciferase reporter assay. Transwell chamber assay and Western blot Method to detect the adhesion and invasion ability of each group of cells and the expression of matrix metalloproteinase 9 (MMP-9) protein. Results: After transfected with Smad4 siRNA, Smad4 protein expression in breast cancer cells and the enhancement of TGF-β-induced 4xSBE activity were significantly inhibited (all P <0.05). Compared with the control cells, (All P <0.05). However, the above-mentioned stimulation of TGF-β in Smad4 siRNA transfected cells was significantly inhibited (all P <0.05). Smad4 siRNA transfection alone Cell invasion and MMP-9 expression had no significant effect. Conclusion: Smad4 siRNA can attenuate the invasive ability of TGF-β induced MDA-MB-231 cells, which may be related to the inhibition of MMP-9 expression.