Cellular recovery of dividing and confluent C3H10T1/2 cells from N-methyl-N′-nitro-N-nitrosoguanidine in the presence of ADP ribosylation inhibitors

Abstract

The relationship between treatment with 3-methoxybenzamide (MBA), a potent inhibitor of ADP-ribosylation reactions and the response of C3H10T1/2 cells to N-methyl-N''-nitro-N-nitrosoguanidine (MNNG) has been examined. Quiescent cells effected potentially lethal damage repair (PLDR) over a 48-h period following MNNG and the repair was coincident with the removal of DNA strand breaks. MBA had no effect on PLDR but was very co-cytotoxic with MNNG in dividing cells. The presence of MBA caused the appearance of an additional number of DNA strand breaks following MNNG in both quiescent and dividing cells. ADP-ribosylation is apparently required for normal cell cycle progression following DNA damage in dividing cells.