Molecular Signature of MT1-MMP: Transactivation of the Downstream Universal Gene in Cancer

Genome-wide expression profiling of MT1-MMP–overexpressing versus MT1-MMP–silenced cancer cells and a further data mining analysis of the preexisting expression database of 190 human tumors of 14 cancer types led us to identify 11 genes, the expression of which correlated firmly and universally with that of MT1-MMP (P < 0.00001). We specifically selected HT1080 cells (HT cells)for our studies because these cells express MT1-MMP naturally. To increase the MT1-MMP expression, we transfected HT cells with MT1-MMP-WT and isolated a pool of the stably transfected HT-MT cells. As a control, we used HT-neo cells transfected with the original plasmid. To silence MT1-MMP, we transfected HT cells with the siRNA construct and isolated HT-siRNA cells. As a second control, we isolated HT-siRNAscr cells which were selected after stable transfection of HT cells with the scrambled siRNA.