重组MMP-14分解区蛋白诱导成骨样细胞凋亡的机制

目的：观察重组基质金属蛋白酶-14(matrix metalloproteinase-14,MMP-14)分解区蛋白（recombinant matrix metalloproteinase-14 catalytic domain, RMC）对人成骨样细胞SaOS-2凋亡的影响，探讨MMP-14分解区蛋白在骨代谢中的作用。 方法：MMP-14分解区蛋白在细胞培养液中的表达用Western blotting检测。RMC对SaOS-2细胞MMP-2酶原激活的影响用明胶酶谱检测，并检测其对SaOS-2细胞黏附功能的影响。细胞凋亡用吖啶橙/溴乙啶染色与ELISA检测。 结果：观察到MMP-14分解区蛋白在SaOS-2细胞培养液中56 kD的MMP-14表达。RMC促进细胞凋亡的作用呈剂量依赖性，且此作用可被EDTA阻断。RMC激活MMP-2酶原，抑制SaOS-2细胞在Ⅰ型胶原上的黏附。 结论：重组MMP-14分解区蛋白可通过降解骨基质蛋白，诱导人成骨样细胞SaOS-2凋亡。

Recombinant MMP-14 catalytic domain inducing the apoptosis of human osteoblastic SaOS-2 cells

OBJECTIVE: To investigate the direct effects of recombinant matrix metalloproteinase-14 (MMP-14) catalytic domain (RMC) on cultured human osteoblastic SaOS-2 cells. METHODS: Western Blotting was used to analyze the expression of MMP-14 in cultured media. The effect of RMC on activation of proMMP-2 was measured by gelatin zymograms analysis, and the influence of RMC on cells adhesion was analyzed as well. The apoptosis was detected by acidine orange/ethidium bromide staining and ELISA. RESULTS: RMC activated proMMP-2 secreted into media by SaOS-2 cells, and this process was blocked by EDTA treatment. RMC inhibited the adhesion of SaOS-2 cells to immobilized Type I collagen in a dose-dependent manner, which was also abolished by EDTA. RMC induced SaOS-2 cells apoptosis in a dose-dependent manner, and apoptosis-inducing activity of MMP-14 catalytic domain was blocked by EDTA. CONCLUSION: Since adhesion of cells to extracellular matrix serves as a survival mechanism in osteoblasts, the catalytic activity of recombinant MMP-14 catalytic domain on matrix proteins contributes to its apoptosis-inducing activity.