Activation of apurinic/apyrimidinic endonuclease in human cells by reactive oxygen species and its correlation with their adaptive response to genotoxicity of free radicals

Chilakamarti V. Ramana, Istvan Boldogh, Tadahide Izumi, Sankar Mitra

Research output: Contribution to journalArticlepeer-review

359 Scopus citations

Abstract

Apurinic/apyrimidinic (AP) endonuclease (APE; EC 4.2.99.18) plays a central role in repair of DNA damage due to reactive oxygen species (ROS) because its DNA 3'-phosphoesterase activity removes 3' blocking groups in DNA that are generated by DNA glycosylase/AP-lyases during removal of oxidized bases and by direct ROS reaction with DNA. The major human APE (APE-1) gene is activated selectively by sublethal levels of a variety of ROS and ROS generators, including ionizing radiation, but not by other genotoxicants- e.g., UV light and alkylating agents. Increased expression of APE mRNA and protein was observed both in the HeLa S3 tumor line and in W138 primary fibroblasts, and it was accompanied by translocation of the endonuclease to the nucleus. ROS-treated cells showed a significant increase in resistance to the cytotoxicity of such ROS generators as H2O2 and bleomycin, but not to UV light. This 'adaptive response' appears to result from enhanced repair of cytotoxic DNA lesions due to an increased activity of APE-1, which may be limiting in the base excision repair process for ROS-induced toxic lesions.

Original languageEnglish (US)
Pages (from-to)5061-5066
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume95
Issue number9
DOIs
StatePublished - Apr 28 1998

ASJC Scopus subject areas

  • General

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