膜型基质金属蛋白酶-1对乳腺癌细胞浸润能力的影响

Effects of MT1-MMP on the in vitro invasiveness of breast cancer cells

目的研究膜型基质金属蛋白酶-1(MT1-MMP)对乳腺癌细胞株浸润能力的影响,并初步探讨其作用机制。方法用20μg/ml刀豆素(ConA)刺激乳腺癌细胞株MDA-MB-453,促使其表达MT1-MMP蛋白,并用免疫细胞化学和Western blot法检测;然后加入外源性MMP-2原酶(proMMP- 2),并用明胶酶谱分析法检测proMMP-2被激活的情况;最后用侵袭实验检测细胞株的浸润能力。实验中将细胞株分为4组:空白对照组、ConA组、MMP-2组和ConA+MMP-2组,各组实验结果进行对比分析。结果利用ConA刺激后,ConA组和ConA+MMP-2组的细胞均表达MT1-MMP蛋白,另两组无MT1-MMP蛋白表达。明胶酶谱分析实验发现,MMP-2组只检测到72 000原酶形式的MMP-2, ConA+MMP-2组同时检测到72 000原酶形式和64 000活酶形式的MMP-2,其余两组检测不到任何形式MMP-2。侵袭实验结果显示,ConA+MMP-2组细胞穿过Marigel胶的细胞数目明显多于其他组。结论MT1-MMP能显著增强乳腺癌细胞株的浸润能力,其机制主要是通过激活MMP-2原酶,降解肿瘤周围的基质成分实现的。

Objective To investigate the effect of membrane type-1 matrix metalloproteinase （ MT1- MMP） on the invasive potential of breast cancer cell and analyze its mechanisms. Methods After treatment of breast cancer MDA-MB-453 cell line with concanavalin A （ ConA, 20 μg/ml） for 24 h, MT1-MMP protein was detected in cancer cells by Western analysis and immunocytochemistry. MDA-MB-453 cells were cultured with exogenous latent proMMP-2 and MMP-2 activity was analyzed by gelatin zymography. The invasive potential of the tumor cells was measured with a membrane invasion culture system. Cancer cells of the cell line were divided into four groups ： the control group treated by neither reagent, group ConA was only treated by ConA, group MMP-2 was treated only by MMP-2, and group ConA ＋ MMP-2 was treated by both ConA and MMP-2. Results The expression of MT1-MMP protein could be detected in groups ConA and ConA ＋ MMP-2, but nothing was detected in control and group MMP-2. There was only 72 000 precursor form of MMP-2 in group MMP-2 and there were both 72 000 precursor form and 64 000 active enzyme form of MMP-2 in group ConA ＋ MMP-2, but there was no forms of MMP-2 in the other two groups detected by gelatin zymography. The largest amount of cells penetrated through Matrigel was observed in group ConA ＋ MMP-2 than in the other three groups. Conclusion MT1-MMP can remarkably promote the invasive potential of breast cancer cells mainly through its ability of activating latent proMMP-2 to degrade extracellular matrix.