Fig. 1

Transient overexpression of MT1-MMP in MCF-7 cells did not result in increased migration and invasion (a) qPCR, immunoblot, and gelatin zymography analysis of MT1-MMP mRNA, protein levels, and proMMP-2 activation ability, respectively, of MCF-7 breast cancer cells transiently transfected with MT1-MMP compared to mock transfected cells (control). Immunoblot analysis (AB6004) showed pro-, active, and degradation forms of MT1-MMP protein in MT1-MMP transfected MCF-7 cells. β-actin was used as a loading control. Gelatin zymography analysis showed that MCF-7 cells transiently transfected with MT1-MMP were capable of activating proMMP-2 after 24 h of incubation as shown by intermediate and active forms of MMP-2. b Gelatin zymography analysis of MCF-7 cells transiently transfected with MT1-MMP and incubated for 12 h with serum-free media (SF, top gel) or MMP-2 conditioned media (CM, bottom gel). Lanes 1 and 2: Controls showing proMMP-2 CM chemically activated by APMA. Lanes 4 and 6: Recombinant TIMP-2 (rTIMP-2) was added at 100 ng/ml to enhance MT1-MMP-mediated proMMP-2 activation. c Immunoblot analysis of MT1-MMP transfected cells showing phospho-ERK1/2 levels. Total ERK1/2 was used as a loading control. d Transwell migration and invasion assays of MCF-7 cells transiently transfected with MT1-MMP. Number of migrated/invaded cells were normalized to control MCF-7 cells and expressed as a mean percentage ± SEM. (ns, p > 0.05 by student’s t-test)