Formamidopyrimidine-DNA Glycosylase Enhances Arsenic-induced DNA Strand Breaks in PHA-stimulated and Unstimulated Human Lymphocytes
Overview
Authors
Affiliations
To confirm that arsenic (As) induces oxidative DNA damage in phytohemagglutinin (PHA)-stimulated and unstimulated human lymphocytes, we used the alkaline comet assay combined with specific enzyme [formamidopyrimidine-DNA glycosylase (FPG)] digestion to measure As-induced base damage. The results showed that the enzyme-sensitive sites were readily detected with the alkaline comet assay after the cells were treated with 10 microM As for 2 hr. The repair patterns observed for FPG-created DNA single strand breaks (SSBs) in As-treated cells were comparable to those in hydrogen peroxide (H(2)O(2))-treated cells. The enzyme-created SSBs, As-induced base damage, were more significant in PHA-stimulated lymphocytes. About 63% and 68% of SSBs induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes by 2-hr repair incubation, but about 34% and 43%, respectively, were repaired in unstimulated cells. About 40% and 49% of base damage induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes, but about 19% and 21%, respectively, were repaired in unstimulated cells. These results indicated that As induced oxidative DNA damage in human lymphocytes at micromolar concentrations. The damaged bases could be chiefly purines or formamidopyrimidines. Like the damage induced by H(2)O(2), As-induced DNA damage was repaired more slowly in unstimulated lymphocytes.
Singh M, Yadav S, Yadav R, Singh U, Shukla Y, Pant K Toxicol Int. 2014; 21(1):8-17.
PMID: 24748729 PMC: 3989920. DOI: 10.4103/0971-6580.128784.
Singh M, Yadav S, Gupta V, Khattri S BMC Complement Altern Med. 2013; 13:193.
PMID: 23889914 PMC: 3733846. DOI: 10.1186/1472-6882-13-193.
Ying S, Myers K, Bottomley S, Helleday T, Bryant H Nucleic Acids Res. 2009; 37(15):5105-13.
PMID: 19553191 PMC: 2731915. DOI: 10.1093/nar/gkp538.
Mukherjee S, Roy M, Dey S, Bhattacharya R J Clin Biochem Nutr. 2008; 41(1):32-42.
PMID: 18392098 PMC: 2274986. DOI: 10.3164/jcbn.2007005.