Effect of HUVEC apoptosis inducing proteinase from Vipera lebetina venom (VLAIP) on viability of cancer cells and on platelet aggregation.

Three cancer cell lines, the human androgen independent prostate cancer PC-3, androgen dependent LNCaP prostate cancer and human chronic myeloid leukaemia cell line K-562, were treated with Sephadex G-100 sf fractions of Vipera lebetina venom and with HUVEC apoptosis inducing heterodimeric metalloproteinase (VLAIP) from the same venom. The venom was separated into nine fractions using size-exclusion chromatography on Sephadex G-100 sf. The effect of V. lebetina venom gel filtration fractions on the viability of studied cancer cells was different: high molecular mass fractions were the most effective on PC-3 cells. The viability of LNCaP cells was inhibited most strongly by the third fraction. The first and the second fractions contain different metalloproteinases including VLAIP that also most effectively reduced the viability of PC-3 cells. VLAIP decreased PC-3 cell viability in a concentration- and time-dependent manner but did not induce apoptosis as shown by DNA fragmentation assay. VLAIP induced changes in cell shape, rounding up and detachment. VLAIP inhibited the PC-3 cell adhesion to extracellular matrix proteins collagen I, fibronectin and vitronectin but not to fibrinogen. VLAIP had no significant effect on the viability of LNCaP and K-562 cells. VLAIP was also capable to inhibit ADP- and collagen-induced platelet aggregation dose-dependently. IC(50) was determined to be 1.89 μM and 0.94 μM, respectively.