Nature of 3,6-bis(5-chloro-2-piperidinyl)-2,5-piperazinedione-induced cytotoxicity in Chinese hamster ovary cells.

We sutdied the effect of 3,6-bis(5-chloro-2-piperidinyl)-2,5-piperazinedione (BCP) on various parameters of the replication cycle and cell grwoth on monolayer cultures of Chinese hamster ovary cells. The results indicated that BCP had no effect on the G-S transition or the passage of cells from metaphase to G. However, BCP prolonged S- and G-phases because of its retarding effect on DNA synthetis. BCP was more toxic to S-phase cells than to G or mitotic cells. As with other alkylating agents, chromosome damage due to BCP could be seen only in cells that had undergone DNA replication after exposure to the drug.