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

Objective: To investigate the effect of membrane type-1 matrix metalloproteinase (MTI-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 microg/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 MTI-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: MTI-MMP can remarkably promote the invasive potential of breast cancer cells mainly through its ability of activating latent proMMP-2 to degrade