Association between genetic polymorphism in biotransformation and DNA repair genes and various biomarkers

P Vodicka PhD^a, R Kumar PhD^b, R Stetina PhD^c, P Soucek PhD^d, PhD Haufroid^e, M Dusinska PhD^f, M Kuricova MSc^a, A Naccarati PhD^a, M Zamecnikova MD^g, J Buchancova MD^h, H Norppa PhDⁱ, L Vodickova PhD^c, K Hemminki MD PhD^b

^aInst. Exper. Med, Acad. Sci. Czech Rep, Prague, Czech Republic, ^bGerman Cancer Inst, Heidelberg, FRG, ^cPurkynje Milit. Med. Acad, Hradec Kralove, Czech Republic, ^dNatl. Inst. Publ. Health, Prague, Czech Republic, ^eCatholic Univ. Louvain, Louvain, Belgium, ^fInst. Prevent. Clin. Med, Bratislava, Slovak Republic, ^gNatl. Inst. Publ. Health, Bratislava, Slovak Republic, ^hDept. Occup. Med, Med. Faculty, Martin, Slovak Republic, ⁱFinnish Inst. Occup. Health, Helsinki, Finland

AIM To analyse the links between genetic polymorphisms in genes coding for biotransformation enzymes (CYP1A1, CYP2E1, EPHX. GSTM1, GSTP1 and GSTT1) and DNA repair enzymes (XPD, XPG, XPC, XRCC1 and XRCC3) and the levels of various biomarkers of genotoxicity in a central European population. METHODS Single nucleotide polymorphisms in genes encoding various biotransformation and DNA repair enzymes were determined by PCR-RFLP based method. For the determination of SSBs, CAs, 1-adenine DNA adducts and HPRT MF conventional or well described methods were used (briefly: comet assay for SSBs, T-cell cloning assay for HPRT MF, cytogenetic analysis for CAs and 32postlabelling method with HPLC/radioisotope detection for DNA adducts). Various parametric or non-parametric tests were employed to evaluate the modulating role of particular genotype as a single factor or in combination (Mann-Whitney U-test, ANOVA, MANOVA, Kruskal-Wallis test). RESULTS Our results showed that increased CA frequencies are associated with EPHX low activity genotype (F=2.4, P=0.043, ANOVA) and with XPD, exon 23 A allele (AA and AC) including genotypes (F=3.6, P=0.028, ANOVA); a substantial influence by XPD exon 23-polymorphism was also confirmed by MANOVA (F=4.2, P=0.017). Single-strand breaks in DNA are modulated by CYP2E1 RsaI and DraI sites polymorphisms (F=5.5, P=0.026 and F=4.7, P=0.038, respectively) as well as by polymorphisms in XPD (F=4.3, P=0.023), XPG (F=4.3, P=0.024) and XRCC1 (F=3.0, P=0.064) genes, analysed by MANOVA. Irradiation-specific DNA repair rates (reflecting mainly base-excision repair) are predominantly affected by XRCC1 (F=5.9, P=0.010), followed by XPC polymorphisms (F=4.2, P=0.046), as analysed by MANOVA. Using MANOVA we discovered that levels of 1-adenine DNA adducts are affected by CYP2E1 polymorphisms (F=6.9, P=0.015 and F=3.2, P=0.030 resp.) and by XPC and XPD polymorphisms (F=6.9, P=0.014 and F=3.1, P=0.040, resp.). Frequencies of mutations at the HPRT locus are associated with CYP2E1 RsaI sites polymorphism (F=5.0, P=0.028) and by XPD polymorphisms (the highest MF being in individuals with the wild-type genotype, F=7.2, P=0.019). Individuals bearing combination of DNA repair polymorphisms XPD, exon 23 AA and AC, XPG, exon 15 GG, XPC, exon 15 CC and AC and XRCC1, exon 10 AG and AA exhibited a significantly higher frequency of CAs in comparison with those with the combination XPD, exon 23 CC, XPG, exon 15 CC and GC, XPC, exon 15 AA and AC and XRCC1, exon 10 GG and AG (3.1?1.7 vs. 1.7?1.3, P=0.0009, Mann-Whitney U-test). These data suggests that gene-gene interactions may play an important role in the modulation of biomarkers level. CONCLUSIONS We report here an association between a set of genetic polymorphisms and important endpoints of genetoxic effect, related to cancer incidence. Our results, in combination with individual DNA repair rates, contribute to our understanding the role of individuald susceptibility in genotoxic carcenogenesis

Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Nice, France; February 7 - 10, 2004; in oral session 996 (Genetic & environmental interactions).