Modulation of human renal cell carcinoma 786-0 MMP-2 and MMP-9 activity by inhibitors and inducers in vitro.

A hallmark of renal cell carcinoma (RCC) invasion is its ability to degrade ECM by local production of gelatinase enzymes. Although many studies on RCC have demonstrated the importance of MMPs, very little information is currently known regarding the effect of inducers and inhibitors. We therefore investigated the effect of inducers and inhibitors on RCC 786-0 in vitro. Human RCC 786-0 (ATCC) was grown in RPMI medium supplemented with 10% FBS, penicillin, and streptomycin in 24-well tissue plates. At near confluence, the cells were washed with PBS; the serum-free medium was incubated with various inducers: phorbol ester (PMA), tumor necrosis factor alpha (TNF-alpha), interleukin 1-beta (IL-1beta) and lipopolysaccharides (LPS). Cells were also incubated with inhibitors: EGCG, doxycycline, and a nutrient mixture with and without PMA; retinoic acid, dexamethasone, H-7; actinomycin D, or cyclohexamide. After 24 h, the medium was removed and analyzed for MMP-2 and MMP-9 by gelatinase zymography. RCC 786-0 secreted two bands, a major band corresponding to MMP-2 and a faint band corresponding to MMP-9. PMA and TNF-alpha, with increased concentration, increased MMP-9 secretion, while IL-1beta and LPS did not significantly modify MMP-9 activity. MMP-2 secretion was not affected by any of the inducers. All the inhibitors tested without and with PMA showed a dose-dependent decrease in both MMP-2 and -9 expression. Further studies are in progress to confirm the role of MMP-9 on Matrigel invasion using PMA, cytokines, and LPS.