BNS-22 is a catalytic inhibitor of DNA topoisomerase II ( TOP2 ). BNS-22 shows the IC 50 values of 2.8 μM and 0.42 μM for human TOP2α and TOP2β, respectively. BNS-22 induces abnormal division and shows anti-proliferative activity.

BNS-22, at concentrations ranging from 0 to 30 μM over 24 to 48 hours, effectively inhibits the growth and alters cell cycle progression in HeLa (human cervical epidermoid carcinoma) cell lines in a dose-dependent manner, with IC 50 values of 4.9 μM at 24 hours and 1.0 μM at 48 hours [1]. Notably, within a shorter exposure window of 0 to 6 hours, BNS-22 does not cause DNA damage nor does it enhance TOP2 toxin-mediated DNA damage, instead exhibiting an antagonistic effect. Further analyses reveal a disruption in mitotic spindle formation and the induction of polyploid cells at a concentration of 3 μM, alongside an increase in cells at the G2/M phase of the cell cycle. Western blot assessments indicate a reduction in etoposide-induced γ-H2AX expression, and a decrease in total cellular TOP2β levels without affecting TOP2α levels [1].