Human renal cancer cell line 786-0 (ATCC) was grown in RPMI medium in 24-well tissue culture plates. At near confluence, the cells were treated with NM, dissolved in media, and tested at 0, 10, 50, 100, 500, and 1000 mg/ml in triplicate at each dose. Cells were also treated with PMA 200 ng/ml to study enhanced MMP-9 activity. Cell proliferation was evaluated by MTT assay, MMP secretion by gelatinase zymography, and invasion through Matrigel.
Zymography demonstrated MMP-2 and MMP-9 secretion by uninduced renal cancer cells with enhanced MMP-9 induced by PMA (200 ng/ml) treatment. NM inhibited the secretion of both MMPs in a dose-dependent fashion with virtual total inhibition of MMP-2 at 500-µg/ml concentration and MMP-9 at 100 µg/ml. The invasion of renal cancer cells through Matrigel was totally inhibited (p=0.0001) by NM at 1000 µg/ml concentration.
Our results support a potential role for the nutrient mixture tested in the treatment of renal cell carcinoma, by inhibition of MMP-2 and MMP-9 secretion and invasion.