Biological activities of Vipegrin, an anti-adhesive Kunitz-type serine proteinase inhibitor purified from Russell's viper venom.

Vipegrin is a 6.8 kDa Kunitz-type serine proteinase inhibitor purified from Russell's viper (Vipera russelii russelii) venom. Kunitz-type serine proteinase inhibitors are non-enzymatic proteins and are ubiquitous constituents of viper venoms. Vipegrin could significantly inhibit the catalytic activity of trypsin. It also posseses disintegrin-like properties and could inhibit collagen and ADP-induced platelet aggregation in a dose-dependent manner. Vipegrin is cytotoxic to MCF7 human breast cancer cells and restricts its invasive property. Confocal microscopic analysis revealed that Vipegrin could induce apoptosis in MCF7 cells. Vipegrin disrupts cell to cell adhesion of MCF7 cells through its disintegrin-like activity. It also causes disruption of attachment of MCF7 cells to synthetic (poly L-lysine) and natural (fibronectin, laminin) matrices. Vipegrin did not cause cytotoxicity on non-cancerous HaCaT, human keratinocytes. The observed properties indicate that Vipegrin may help the development of a potent anti-cancer drug in future.