Increased poly(ADP-ribose) polymerase activity during repair of (+/-)-anti-benzo[a]pyrene diolepoxide-induced DNA damage in human peripheral blood lymphocytes in vitro.

Poly(ADP-ribose) polymerase, which catalyzes the formation of poly(ADP-ribose) polymers, is an enzyme involved in cell proliferation, differentiation and transformation as well as in recovery from DNA damage. Poly(ADP-ribose) polymers are rapidly synthesized from the ADP-ribose moieties from intracellular NAD+, which, as a consequence, is depleted. It has been shown that DNA strand breaks are required for enzyme activation and it is suggested that one of the functions of poly(ADP-ribosylation) is to improve accessibility of damaged sites to other DNA repair enzymes. The aim of this study was to investigate whether poly(ADP-ribosylation) is involved in repair of (+/-)-7 beta,8 alpha-dihydroxy-9 alpha,10 alpha-epoxy-7,8,9,10- tetrahydrobenzo[a]pyrene [(+/-)-anti-BPDE]-induced DNA damage in human lymphocytes in vitro. Results show that (+/-)-anti-BPDE is capable of inducing poly(ADP-ribosylation), NAD+ depletion and inhibition of proliferation in phytohemagglutinin-stimulated human peripheral blood lymphocytes. Also, repair of (+/-)-anti-BPDE induced DNA damage was confirmed by both unscheduled DNA synthesis and (+/-)-anti-BPDE-deoxyguanosine adduct removal. Based on these findings, it is concluded that poly(ADP-ribosylation) is involved in (+/-)-anti-BPDE-induced DNA repair in these cells. In addition, these results confirm the possible relation between poly(ADP-ribosylation), NAD+ depletion and inhibition of proliferation, after induction of DNA damage.