Inhibitory effects of statins on the mRNA expressions and protein activities of MMPs. B16BL6 cells were treated with 0.05 μM fluvastatin or 0.1 μM simvastatin for 3 d. (A) Equal amounts of total RNA were reverse-transcribed to generate cDNAs that were used for PCR analysis of the mRNA expressions of MMPs in B16BL6 cells. (B, C) Activities of (B) type I collagenase (MMP-1) and (C) type IV collagenases (MMP-2 and MMP-9) in B16BL6 cells. Conditioned media were harvested, and the type I and type IV collagenase activities were measured by FITC-conjugated type I and type IV collagen breakdown assays, respectively. The results are representative of 5 independent experiments. (D) Image showing a western blot of the MT1-MMP protein expression.