Development of APE1 enzymatic DNA repair assays: Low APE1 activity is associated with increase lung cancer risk

Ziv Sevilya, Yael Leitner-Dagan, Mila Pinchev, Ran Kremer, Dalia Elinger, Flavio Lejbkowicz, Hedy S. Rennert, Laurence S. Freedman, Gad Rennert, Tamar Paz-Elizur, Zvi Livneh

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

The key role of DNA repair in removing DNA damage and minimizing mutations makes it an attractive target for cancer risk assessment and prevention. Here we describe the development of a robust assay for apurinic/apyrimidinic (AP) endonuclease 1 (APE1; APEX1), an essential enzyme involved in the repair of oxidative DNA damage. APE1 DNA repair enzymatic activity was measured in peripheral blood mononuclear cell protein extracts using a radioactivity-based assay, and its association with lung cancer was determined using conditional logistic regression with specimens from a population-based case-control study with 96 lung cancer cases and 96 matched control subjects. The mean APE1 enzyme activity in case patients was 691 [95% confidence interval (CI) = 655-727] units/ng protein, significantly lower than in control subjects (mean = 793, 95% CI = 751-834 units/ng protein, P = 0.0006). The adjusted odds ratio for lung cancer associated with 1 SD (211 units) decrease in APE1 activity was 2.0 (95% CI = 1.3-3.1; P = 0.002). Comparison of radioactivity- and fluorescence-based assays showed that the two are equivalent, indicating no interference by the fluorescent tag. The APE1Asp148Glu SNP was associated neither with APE1 enzyme activity nor with lung cancer risk. Taken together, our results indicate that low APE1 activity is associated with lung cancer risk, consistent with the hypothesis that 'bad DNA repair', rather than 'bad luck', is involved in cancer etiology. Such assays may be useful, along with additional DNA repair biomarkers, for risk assessment of lung cancer and perhaps other cancers, and for selecting individuals to undergo early detection techniques such as low-dose CT.

Original languageEnglish
Pages (from-to)982-991
Number of pages10
JournalCarcinogenesis
Volume36
Issue number9
DOIs
StatePublished - Sep 2015
Externally publishedYes

Bibliographical note

Publisher Copyright:
© The Author 2015. Published by Oxford University Press.

Funding

FundersFunder number
National Cancer InstituteU01CA111219

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