Induction of reversible protein-linked DNA breaks in human osteogenic sarcoma cells by novel cytocidal colchicine derivatives which inhibit DNA topoisomerase II in vitro: Absence of cross-resistance in a colchicine-resistant sub-clone

Abstract Two colchicine derivatives gave dose-dependent cytocidal effects in human osteogenic sarcoma cells. Unlike colchicine, the analogues stimulated formation of intacellular protein-linked DNA breaks, they inhibited DNA topoisomerase II in vitro , and their cytotoxic action was not modulated by the P-glycoprotein drug-efflux pump.