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Your Environment. Your Health.

NICKEL AND TOXIC TOPOISOMERASE I PRODUCTS

Export to Word (http://www.niehs.nih.gov//portfolio/index.cfm?do=portfolio.grantdetail&&grant_number=R01ES031979&format=word)
Principal Investigator: Zhitkovich, Anatoly
Institute Receiving Award Brown University
Location Providence, RI
Grant Number R01ES031979
Funding Organization National Institute of Environmental Health Sciences
Award Funding Period 18 Mar 2021 to 31 Dec 2025
DESCRIPTION (provided by applicant): Project Summary Nickel (Ni) is a major industrial metal and a common environmental contaminant that is firmly established as a human carcinogen. Inhalation of Ni compounds in occupationally exposed populations has been found to cause lung and nasal cancers. Tumorigenicity of different forms of Ni was linked to the intracellular presence of Ni(II) ions. Mechanisms of carcinogenic activity of Ni are poorly understood, as Ni compounds were weak or negative in the standard mutagenicity assays and Ni(II) ions do not react with DNA. Consequently, Ni is commonly described as a nongenotoxic carcinogen. However, Ni- treated cultured cells and lymphocytes from Ni-exposed workers have consistently shown the presence of chromosomal rearrangements that typically originate from DNA double-strand breaks (DSBs). Also contradicting its nongenotoxic description is the ability of Ni(II) to cause covalent DNA-protein crosslinks (DPCs) in experimental animals and in occupationally exposed individuals. The presence of chromosomal abnormalities and DPCs despite the apparent lack of mutagenicity and DNA reactivity suggests that Ni may engage some unusual genotoxicity mechanisms. Based on extensive preliminary results, this project is designed to investigate a novel hypothesis that Ni(II) causes DSBs, DPCs, and cell transformation by inducing genotoxic topoisomerase I-DNA products. The proposed studies will determine (1) mechanisms of Ni(II)-induced defects in homologous recombination repair of DSBs, (2) the importance of error-prone DSB repair in the production of oncogenic genetic changes by Ni(II), and (3) formation and pathophysiological significance of Ni-induced topoisomerase I-containing DPCs and DNA breaks. The completion of this work is expected to uncover molecular mechanisms of the formation of oncogenic genetic abnormalities by a nonmutagenic carcinogen Ni and identify novel biomarkers of DNA damage by this metal.
Science Code(s)/Area of Science(s) Primary: 09 - Genome Integrity
Secondary: 03 - Carcinogenesis/Cell Transformation
Publications See publications associated with this Grant.
Program Officer David Balshaw
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