Tumor progression and expression of matrix metalloproteinase-2 (MMP-2) mRNA by human urinary bladder cancer cells

Tumor cells at the stage of tumor progression build up a high tolerance to intrinsic and extrinsic defence systems and/or therapeutic procedures, and the cells deeply infiltrate the adjacent tissue, which is followed by tumor metastasis to remote organs and tissues. This study was designed to invest igate the relationship between expression of matrix metalloproteinase-2 (MM P-2) and invasiveness of human bladder cancer cells, using cell lines deriv ed from a parental human urinary bladder tumor cell line, T24. Two subpopul ations of the human bladder cancer cell line T24, Hi-T24 and Lo-T24, were s elected using an invasion assay and then expression of MMP-2 mRNA and prote in was analyzed by reverse-transcription polymerase chain reaction (RT-PCR) and enzyme immunoassay (EIA). The gross morphology, cell growth rate,and a dhesion activity to a basement membrane extract (matrigel) of the high-inva sive Hi-T24 cells were similar to those of the low-invasive Lo-T24 cells, b ut the Hi-T24 cells were 3.8-fold more haptotactic through matrigel than th e Lo-T24 cells. The haptotactic activity of the Hi-T24 cells was suppressed by the addition of an anti-MMP-2 antibody, and the amounts of MMP-2 protei n secreted into the spent medium by the Hi-T24 and Lo-T24 cells were 7.8 +/ - 0.2 and 3.8 +/- 0.3 ng/ml (P < 0.05), respective ly. The quantities of ti ssue inhibitor of metalloproteinase-2 (TIMP-2) protein secreted by Hi-T24 a nd Lo-T24 cells were 133.2 +/- 4.3 and 168.7 +/- 5.6 ng/ml, respectively (P < 0.05). The levels of transcription of the genes encoding MMP-2 and the t ransmembrane MMP, MT-MMP, evaluated by RT-PCR, were higher in the Hi-T24 ce lls than in the Lo-T24 cells. Expression of the TIMP-2 gene was slightly lo wer in the Hi-T24 cells than in the Lo-T24 cells. These results indicate th at expression of the metalloproteinases are imbalanced at the gene level in human urinary bladder cancer cells at the stage of tumor progression.