Bacillus intermedius ribonuclease (BINASE) induces apoptosis in human ovarian cancer cells

The cytotoxic effects of Bacillus intermedius RNase (binase) towards ovarian cancer cells (SKOV3 and OVCAR5) were studied in comparison to normal ovarian epithelial cells (HOSE1 and HOSE2). Binase decreased viability and induced the selective apoptosis of ovarian cancer cells. The apoptosis rate was 50% in SKOV3 and 48% in OVCAR5 cells after 24 h of binase treatment (50 μg/ml). Binase-induced apoptosis in these cell lines was accompanied by caspase-3 activation and poly(ADP-ribose) polymerase fragmentation. Normal ovarian epithelial cells were not affected by binase, except for a slight decrease of HOSE2 cell viability and the appearance of traces of activated caspase-3, but not the poly(ADP-ribose) polymerase 85-kDA fragment. Binase did not induce alteration of EZH2 (enhancer of zeste-homolog-2) protein expression neither, in tumor nor in normal cells. In conclusion, selective binase-induced cell death and apoptosis via poly(ADP-ribose) polymerase fragmentation may serve as a new treatment option against ovarian cancer progression.