title: Increased risk of lung cancer associated with a functionally impaired polymorphic variant of the human DNA glycosylase NEIL2.
abstract: Human NEIL2, one of five oxidized base-specific DNA glycosylases, is unique in preferentially repairing oxidative damage in transcribed genes. Here we show that depletion of NEIL2 causes a 6-7-fold increase in spontaneous mutation frequency in the HPRT gene of the V79 Chinese hamster lung cell line. This prompted us to screen for NEIL2 variants in lung cancer patients' genomic DNA. We identified several polymorphic variants, among which R103Q and R257L were frequently observed in lung cancer patients. We then characterized these variants biochemically, and observed a modest decrease in DNA glycosylase activity relative to the wild type (WT) only with the R257L mutant protein. However, in reconstituted repair assays containing WT NEIL2 or its R257L and R103Q variants together with other DNA base excision repair (BER) proteins (PNKP, Polβ, Lig IIIα and XRCC1) or using NEIL2-FLAG immunocomplexes, an ~5-fold decrease in repair was observed with the R257L variant compared to WT or R103Q NEIL2, apparently due to the R257L mutant's lower affinity for other repair proteins, particularly Polβ. Notably, increased endogenous DNA damage was observed in NEIL2 variant (R257L)-expressing cells relative to WT cells. Taken together, our results suggest that the decreased DNA repair capacity of the R257L variant can induce mutations that lead to lung cancer development.
authors.affiliation: Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA.
authors.forename: Sanjib
authors.initials: S
authors.lastname: Dey
authors.forename: Amit K
authors.initials: AK
authors.lastname: Maiti
authors.forename: Muralidhar L
authors.initials: ML
authors.lastname: Hegde
authors.forename: Pavana M
authors.initials: PM
authors.lastname: Hegde
authors.forename: Istvan
authors.initials: I
authors.lastname: Boldogh
authors.forename: Partha S
authors.initials: PS
authors.lastname: Sarkar
authors.forename: Sherif Z
authors.initials: SZ
authors.lastname: Abdel-Rahman
authors.forename: Altaf H
authors.initials: AH
authors.lastname: Sarker
authors.forename: Bo
authors.initials: B
authors.lastname: Hang
authors.forename: Jingwu
authors.initials: J
authors.lastname: Xie
authors.forename: Alan E
authors.initials: AE
authors.lastname: Tomkinson
authors.forename: Mian
authors.initials: M
authors.lastname: Zhou
authors.forename: Binghui
authors.initials: B
authors.lastname: Shen
authors.forename: Guanghai
authors.initials: G
authors.lastname: Wang
authors.forename: Chen
authors.initials: C
authors.lastname: Wu
authors.forename: Dianke
authors.initials: D
authors.lastname: Yu
authors.forename: Dongxin
authors.initials: D
authors.lastname: Lin
authors.forename: Victor
authors.initials: V
authors.lastname: Cardenas
authors.forename: Tapas K
authors.initials: TK
authors.lastname: Hazra
mesh_terms: D000368:Aged; D000818:Animals; D015153:Blotting, Western; D016466:CHO Cells; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D004249:DNA Damage; D045647:DNA Glycosylases / Q000235:genetics* / Q000378:metabolism; D004260:DNA Repair / Q000235:genetics; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D005787:Gene Frequency; D005838:Genotype; D057809:HEK293 Cells; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D008175:Lung Neoplasms / Q000201:enzymology / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D059645:Mutation Rate; D016376:Oligonucleotides, Antisense / Q000235:genetics; D020641:Polymorphism, Single Nucleotide; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012307:Risk Factors
chemical_list: D016376:Oligonucleotides, Antisense; D007041:Hypoxanthine Phosphoribosyltransferase; D045647:DNA Glycosylases; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; C473642:NEIL2 protein, human