Effect of KP418 and KP1019 on MMPs production and/or activity. MDA-MB-231, and HBL-100 cells were treated for 1 hour with KP418 and KP1019  M, then incubated for additional 24 hours in serum-starved complete medium containing 0.1% BSA. Supernatants containing MMPs were collected and concentrated and equal protein amounts (100 g) subjected to SDS-PAGE. Gelatine digestion by proteases is detected as white bands against a blue background (a, b). Band digestion is quantified by using Image Master 2D version 4.01 and Magic Scan 32 version 4.3 software (c).