Polymorphic trial in oxidative damage of arsenic exposed Vietnamese

Arsenic causes DNA damage and changes the cellular capacity for DNA repair. Genes in the base excision repair (BER) pathway influence the generation and repair of oxidative lesions. Single nucleotide polymorphisms (SNPs) in human 8-oxoguanine DNA glycosylase (hOGG1) Ser326Cys; apurinic/apyrimidinic endonuclease (APE1) Asp148Glu; X-ray and repair and cross-complementing group 1 (XRCC1) Arg280His and Arg399Gln in the BER genes were analyzed, and the relationship between these 4 SNPs and the urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) concentrations of 100 Vietnamese population exposed to arsenic was investigated. Individuals with hOGG1 326Cys/Cys showed significantly higher urinary 8-OHdG concentrations than did those with 326 Ser/Cys and Ser/Ser. As for APE1 Asp148Glu, heterozygous subjects showed significantly higher urinary 8-OHdG concentrations than did those homozygous for Asp/Asp. Moreover, global ethnic comparison of the allelic frequencies of the 4SNPs was performed in 10 population and previous reported data. The mutant allele frequencies of hOGG1 Ser326Cys in the Asian populations were higher than those in the African and Caucasian populations. As for APE1 Asp148Glu, Caucasians showed higher mutant frequencies than those shown by African and Asian populations. Among Asian populations, the Bangladeshi population showed relatively higher mutant allele frequencies of the APE1 Asp148Glu polymorphism. This study is the first to demonstrate the existence of genetic heterogeneity in a worldwide distribution of SNPs (hOGG1 Ser326Cys, APE1 Asp148Glu, XRCC1 Arg280His, and XRCC1 Arg399Gln) in the BER genes.     

hOGG1 SER326CYS genetic polymorphism in a Turkish population

Oxidative DNA damage, caused by either endogenous or exogenous sources of reactive oxygen species (ROS), has been linked to aging, chronic degenerative diseases, inflammatory diseases and cancers. 8-Hydroxydeoxyguanine (8-OHdG) is a major lesion produced by ROS. Among various types of DNA base modifications, 8-OHdG has been the most widely studied and is considered a key biomarker of oxidative DNA damage. Human 8-oxoguanine DNA glycosylase 1 (hOGG1) is a key component of the base excision repair (BER) pathway and catalyzes the removal of 8-OHdG. Ethnic and inter-individual differences in hOGG1 activity and several kinds of polymorphisms at the hOOG1 gene locus have been observed in the different populations studied so far. Since no information is available on the inter-individual variability of the hOGG1 genotype in the Turkish population, we genotyped 206 healthy, unrelated Turkish individuals. The allelic frequencies of the hOGG1 gene in the Turkish population were found to be 0.50, 0.41 and 0.09 (Ser/Ser, Ser/Cys and Cys/Cys, respectively). Our results are similar to those for Caucasians studied previously but are different from Asian populations. It seems that there is a growing need for extensive genotype studies with respect to the hOGG1 gene due to its importance to various types of cancer and to smoking habits.     

The hOGG1 Ser326Cys polymorphism and Huntington's disease

Increasing evidence supports a role for oxidative DNA damage and impaired DNA repair mechanisms in the pathogenesis of age related neurodegenerative diseases. Within this context there is a current interest in the understanding of the role played by polymorphisms of DNA repair genes in the inter-individual risk to develop neurodegenerative pathologies, as well as in the onset and the progression of disease symptoms. Particularly, somatic CAG repeat expansion of the gene encoding for huntingtin has been observed in tissues of patients affected by Huntington's disease (HD), including blood and brain. Recent evidence suggests that somatic CAG repeat expansion in HD cells might contribute to disease age at onset and is mediated by the DNA repair OGG1 enzyme, during the removal of 8-oxoguanine (8-oxoG) from the DNA. There is also evidence that the expression of hMTH1, which removes 8-oxoG from the nucleotide pool, protects mice from HD-like symptoms, and progenitor striatal cells from the toxic effects of the mutant huntingtin. The hOGG1 Ser326Cys polymorphism results in reduced OGG1 activity and increased 8-oxoG formation. In the present study, performed on blood DNA from 91 HD subjects, we observed that bearers of the mutant Cys326 allele (Ser326Cys + Cys326Cys) tend to have an increased number of CAG repeats of the expanded HD allele (P = 0.049); moreover bearers of at least one copy of the mutant Cys326 allele, mainly heterozygous subjects, showed a significant (P = 0.041) earlier disease onset than Ser326Ser wild-type individuals, suggesting a possible role of the hOGG1 Ser326Cys polymorphism in HD phenotype.     

Biomarkers of nucleic acid oxidation, polymorphism in, and expression of, hOGG1 gene in styrene-exposed workers

This study investigated nucleic acid oxidation associated with styrene exposure, mRNA expression levels of hOGG1 gene and the role of the genetic polymorphism Ser326Cys of human 8-oxoguanine DNA N-glycosylase 1 (hOGG1) in 60 styrene-exposed workers and 50 unexposed clerks. Biomarkers of exposure (styrene in blood, mandelic and phenylglyoxylic acids and 4-vinylphenol in urine) and urinary biomarkers of nucleic acid oxidation, namely 8-oxo-7,8-dihydro-2′-deoxyguanosine (U-8-oxodGuo), 8-oxo-7,8-dihydroguanosine (U-8-oxoGuo) and 8-oxo-7,8-dihydroguanine (U-8-oxoGua) were determined by liquid chromatography–tandem mass spectrometry. The levels of 8-oxodGuo adduct and 2′-deoxyguanosine (dGuo) were measured by HPLC in DNA from white blood cells (WBC). Genomic DNA and RNA from blood samples were used to characterize the Ser326Cys polymorphism and the mRNA expression levels of the hOGG1 gene, respectively, by PCR-based methods. Exposed workers showed lower values of 8-oxodGuo/10⁵ dGuo ratio in WBC-DNA but higher concentrations of U-8-oxoGuo compared to controls (p = 0.002 and p = 0.008, respectively, t-test for independent samples). In the whole group, all urinary biomarkers of nucleic acid oxidation correlated with both the sum of mandelic and phenylglyoxylic acids (rho > 0.33, p < 0.0001) and 4-vinylphenol (rho > 0.29, p < 0.001), whereas 8-oxodGuo/10⁵ dGuo in WBC showed a negative correlation with exposure parameters (rho < −0.24, p < 0.02). Subjects bearing the hOGG1 Ser/Ser genotype showed lower values of 8-oxodGuo/10⁵ dGuo in WBC than those with at least one variant Cys allele (0.34 ± 0.16 vs 0.45 ± 0.21, p = 0.008). In the subgroup of hOGG1 Ser/Ser subjects, laminators showed lower levels of WBC 8-oxodGuo/10⁵ dGuo ratio and significantly higher concentrations of U-8-oxoGua than controls (p = 0.07 and p = 0.01, respectively, t-test for independent samples). Interestingly, workers showed higher levels of hOGG1 expression compared to controls (p < 0.0005). Styrene exposure seems to be associated with oxidation damage to nucleic acids, particularly to RNA and with an induction of the BER system.     

OGG1 Ser326Cys polymorphism interacts with cigarette smoking to increase oxidative DNA damage in human sperm and the risk of male infertility

8-Oxoguanine DNA glycosylase 1 (OGG1) plays an important role in repairing oxidative DNA damage induced by chemical agents, such as tobacco. This study examined the effects of OGG1 Ser326Cys polymorphism and cigarette smoking, alone or combined, on sperm oxidative DNA damage and the risk of male infertility. A total of 620 idiopathic infertile subjects and 480 fertile controls were recruited in this study. Sperm 8-hydroxydeoxyguanine (8-OHdG) was measured by immunofluorescent assay using flow cytometry and genotypes were determined by OpenArray platform with a chip-based Taq-Man genotyping technology. Our results demonstrated that both cigarette smoking and OGG1 polymorphism can affect the sperm 8-OHdG levels. Individuals with variant Cys/Cys homozygote showed higher levels of sperm 8-OHdG than wide-type homozygote carriers (Ser/Ser). Stratified analysis found that the association between OGG1 polymorphism and sperm 8-OHdG levels was only observed among smokers with pack-years ≥5 but not among those subjects with pack-years < 5 (pack-years = packs smoked per day × years as a smoker). Further analysis based on the case–control study revealed that variant allele (Cys) of OGG1 was significantly associated with male infertility risk in a dominant model (OR = 1.35, 95% CI: 1.01–1.82; trend P < 0.001). Furthermore, we found a significant gene–environment interaction between OGG1 Ser326Cys polymorphism and cigarette smoking in relation to male infertility risk (P_interation = 0.0003). These findings provided the first evidence about potential interactive effects of OGG1 polymorphism and cigarette smoking on male infertility risk.     

hOGG1 promoter methylation,hOGG1 genetic variants and their interactions for risk of coal-borne arsenicosis: A case-control study

To identify the effect of hOGG1 methylation, Ser326Cys polymorphism and their interactions on the risk of coal-borne arsenicosis, 113 coal-borne arsenicosis subjects and 55 reference subjects were recruited. Urinary arsenic contents were analyzed with ICP-MS. hOGG1 methylation and Ser326Cys polymorphism was measured by mehtylation-specific PCR and restriction fragment length polymorphism PCR in PBLCs, respectively. The results showed that the prevalence of methylated hOGG1 and variation genotype (326 ^Ser/Cys & 326 ^Cys/Cys) were increased with raised levels of urinary arsenic in arsenicosis subjects. Increased prevalence of methylated hOGG1 and variation genotype were associated with raised risk of arsenicosis. Moreover, the results revealed that variant genotype might increase the susceptibility to hOGG1 methylation. The interactions of methylated hOGG1 and variation genotype were also found to contribute to increased risk of arsenicosis. Taken together, hOGG1 hypermethylation, hOGG1 variants and their interactions might be potential biomarkers for evaluating risk of coal-borne arsenicosis.     

Genetic polymorphisms in hMTH1, hOGG1 and hMYH and risk of chronic benzene poisoning in a Chinese occupational population

Oxidative damage to DNA induced by benzene is an important mechanism of its genotoxicity, which leads to chronic benzene poisoning (CBP). Therefore, genetic variation in DNA repair genes may contribute to susceptibility to CBP in the exposed population. We hypothesized that single nucleotide polymorphisms (SNPs) in hMTH1, hOGG1 and hMYH genes are associated with risk of CBP. We genotyped SNPs at codon 83 of hMTH1, codon 326 of hOGG1, and codon 324 of hMYH in 152 CBP patients and 152 healthy workers occupationally exposed to benzene without poisoning manifestations. The genotypes were determined by polymerase chain reaction-restrained fragment length polymorphism (PCR-RFLP) technique. There were 2.51-fold [adjusted odds ratio (OR_adj), 2.51; 95% CI, 1.14-5.49; P = 0.02] and 2.49-fold (OR_adj, 2.49; 95% CI: 1.52-4.07; P < 0.01) increased risk of CBP for individuals carrying genotypes of hMTH1 83Val/Met + Met/Met and hOGG1 326Cys/Cys, respectively. Compared with individuals carrying genotypes of hOGG1 326Cys/Cys and hMYH 324His/His at the same time, there was a 0.33-fold (OR_adj, 0.33; 95% CI: 0.15-0.72; P < 0.05) decreased risk of CBP for those with genotypes of hOGG1 326Ser/Cys + Ser/Ser and hMYH 324His/Gln + Gln/Gln. In the smoking group, there was a 0.15-fold (OR_adj, 0.15; 95% CI, 0.03-0.68; P = 0.01) decreased risk of CBP for subjects carrying genotypes of hMYH 324His/Gln + Gln/Gln compared with those of genotype of hMYH 324His/His. Therefore, our results suggested that polymorphisms at codons 83 of hMTH1 and codon 326 of hOGG1 might contribute to CBP in a Chinese occupational population.     

8-羟基鸟嘌呤糖苷酶1基因多态性与喉癌易感性的关系

目的:探讨8-羟基鸟嘌呤糖苷酶1基因(hOGG1)Ser326Cys多态性与喉癌遗传易感性的关系.方法:采用病例-对照设计,选择72例喉鳞状细胞癌患者(病例组),并与72例性别比一致,平均年龄相差＜5岁的对照组进行比较.采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)技术分析hOGG1c.326多态性.结果:病例组hOGG1c.326杂合型及突变(Ser/Cys Cys/Cys)比例高于对照组(P＜0.05),携带hOGG1c.326Ser/Cys Cys/Cys基因型个体较携带hOGG1c.326Ser/Ser基因型的个体患喉癌的风险升高了2.54倍.结论:hOGG1c.326(Ser/Cys或Cys/Cys)基因型可能是喉癌发病的风险因子,其可作为一种易感性分子标志物,对喉癌的早期预防具有一定的参考价值.     

Interethnic differences of <Emphasis Type="Italic">PEPT2</Emphasis> (<Emphasis Type="Italic">SLC15A2</Emphasis>) polymorphism distribution and associations with cephalexin pharmacokinetics in healthy Asian subjects

Objectives  The aims of this study were to characterize the population frequency of PEPT2 (SLC15A2) polymorphic variants in three Asian ethnic populations, namely Chinese, Malay and Asian Indian, and to investigate the associations of ethnicity (Chinese vs. Asian Indian), PEPT2 haplotype and cephalexin pharmacokinetics in healthy Asian subjects. Methods   PEPT2 polymorphisms were screened from a cohort of 96 Chinese, 96 Malay and 96 Asian Indian subjects. Cephalexin (1000 mg, orally) pharmacokinetics was characterized in an additional 15 Chinese and 15 Asian Indian healthy subjects. These 30 subjects were subsequently genotyped for their PEPT2 polymorphisms. Results  In total, ten common single nucleotide polymorphisms (SNPs) were detected in the three populations, forming two PEPT2 haplotypes. There were significant ethnic differences in PEPT2 haplotype distribution: the frequencies of the *1 and *2 alleles were 0.307 and 0.693 in the Chinese population, 0.495 and 0.505 in the Malay population and 0.729 and 0.271 in Asian Indian population, respectively. The C _max of cephalexin was significantly lower in the Chinese (29.80 ± 4.09 μg ml⁻¹) population than in the Asian Indian one (33.29 ± 4.97 μg ml⁻¹; P = 0.045). This difference could be explained by the higher average body weight of the Chinese population. There was no other significant difference in cephalexin pharmacokinetics between either ethnic or PEPT2 genotype groups. Conclusion   PEPT2 polymorphism distributions differ significantly between Chinese, Malay and Asian Indian populations. However, cephalexin pharmacokinetics is not meaningfully different between Chinese and Asian Indians. The association between the PEPT2 haplotype and cephalexin pharmacokinetics could not be confirmed, and future studies under better controlled conditions are needed.     

Pharmacogenetics of <Emphasis Type="Italic">SLCO1B1</Emphasis>: haplotypes,htSNPs and hepatic expression in three distinct Asian populations

Objective The aim of this study was to characterize the population frequency of SLCO1B1 polymorphic variants in three distinct healthy Asian populations, namely Chinese (n = 100), Malay (n = 100) and Indian (n = 100), and to explore the association between haplotype-tagged single nucleotide polymorphisms (htSNPs) on hepatic SLCO1B1 mRNA expression. Methods The distribution of polymorphic variants in the SLCO1B1 gene at eight loci that spanned approximately 48 kb was investigated in the three different Asian ethnic groups and in 32 non-cancerous liver tissues from Chinese patients. Results Of the 26 polymorphisms screened, we found eight polymorphic variants that differed in genotypic and allelic frequencies between the Chinese, Malay and Indian populations. Significant interethnic differences were observed in the genotype frequency distributions across the promoter SNP [g.-11187G>A (P = 0.030)] as well as three coding region SNPs [c.388G>A (P < 0.001); c.571T>C (P < 0.001); c.597C>T (P < 0.001)] in the healthy subjects. Haplotype analysis revealed 12 different haplotypes in both the Chinese and Malay populations and 18 haplotypes in the Indian population. In both the Malay and Indian populations, the htSNPs were c.388A>G, c.571T>C and c.597C>T, whereas in the Chinese population they were g.-11187G>A, c.388A>G and c.597C>T. The c.388A>G and c.597C>T htSNPs accounted for more than 70% of the variations between the three major haplotypes in each Asian ethnic group. In terms of the c.388A>G htSNPs, genotypic-phenotypic association analyses revealed that there was no effect on SLCO1B1 expression in hepatic tissues; in addition, no genotypic-phenotypic associations were evident with regards to the c.597C>T htSNP. Conclusion Future studies should investigate the phenotypic effects of the c.388A>G htSNP on the disposition of OATP1B1 substrates in Asian populations. An erratum to this article can be found at     

Rapid detection of the hOGG1 Ser326Cys polymorphism using LightCycler technology

Human 8-oxoguanine DNA glycosylase 1 (hOGG1) plays an important role in the repair of 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8-oxodGuo), one of the major constituents in DNA damage. A recent in vitro study showed that the hOGG1 326Cys polymorphism (rs1052133) exhibits reduced 8-oxodGuo repair activity. This study aimed to develop a LightCycler (LC) assay to analyze the C>G polymorphism (Ser326Cys) in exon 7 of the hOGG1 gene followed by validation of the method using DNA samples from 260 polycyclic aromatic hydrocarbons(PAH)-exposed workers with known 8-oxodGuo DNA-adduct values measured by HPLC. Twenty DNA samples were analyzed by a PCR-RFLP analysis with Fnu4H I to generate control DNA. LC melting curve analyses of the hOGG1 exon 7 PCR product were characteristic of the probes hybridized to the non-mutated Ser-type (CC) at 65 degrees C, or to the Cys mutant (GG) at 59 degrees C. The distribution in the population of PAH-exposed workers (N=260) was 58% (CC), 38%(CG), and 4% (GG). The minor G allele displayed a frequency of 23 %. The distribution of 8-oxodGuo adducts for the Ser326Cys variants of hOGG1 revealed geometric means (GM) of 5.83 (CC), 5.27 (CG), and 6.53 (GG) 8-oxodGuo adducts/10(6)dGuo. Corresponding GM values of current smokers were 5.7 (CC), 5.6 (CG) and 7.0 (GG) 8-oxodGuo adducts/10(6) dGuo. The analysis of the Ser326Cys polymorphism in 260 DNA samples with this new LC assay revealed that this method is reliable for high throughput analysis of this key polymorphism in the hOGG1 gene.     

The human 8-oxoguanine DNA N-glycosylase 1 (hOGG1) DNA repair enzyme and its association with lung cancer risk

OBJECTIVE: The human 8-oxoguanine DNA N-glycosylase 1 gene encodes a DNA glycosylase that is involved in the base excision repair of 8-hydroxy-2-deoxyguanine from oxidatively-damaged DNA and expressed in lung tissue. The codon 326 polymorphism in the hOGG1 gene has been suggested to reduce DNA repair enzyme activity based on in vitro functional analysis. The goal of the present study is to determine whether the codon 326 polymorphism was significantly associated with alterations in individual risk for lung cancer. METHODS: To determine whether hOGG1 plays a role in risk for lung cancer, we measured the prevalence of the Ser326Cys polymorphism in incident lung cancer patients and matched non-cancer controls. hOGG1 genotyping was performed by PCR-restriction fragment length polymorphism analysis of genomic DNA isolated from 179 Caucasian lung cancer cases and 358 controls individually matched in a 1:2 ratio by race-, sex- and age (+/- 5 years). RESULTS: Significantly increased risk for lung cancer was observed for both the hOGG1 326 (odds ratio [OR] = 1.9, 95% confidence interval [CI] = 1.2-2.9) and hOGG1 326 genotypes (OR = 3.8, 95% CI = 1.4-10.6). The increased risk for lung cancer was observed for subjects with both the hOGG1 326 (OR = 1.7, 95% CI = 1.1-2.8) and hOGG1 326 genotypes (OR = 4.9, 95% CI = 1.5-16.1) in ever-smokers. A significant association was found between hOGG1 genotypes and lung cancer risk with a dose-dependent effect with smoking. Significantly increased risk for variant hOGG1 genotypes was observed for all non-small cell lung cancer patients. CONCLUSION: These results suggest that the hOGG1 Ser326Cys polymorphism plays an important role in the risk for lung cancer and is linked to exposure to tobacco smoke.     

Genetic polymorphisms and linkage disequilibrium of sulfotransferase SULT1A1 and SULT1A2 in a Korean population: comparison of other ethnic groups

Aims: To determine the allele frequencies of sulfotransferases (SULTs) 1A1 and 1A2 and their linkage disequilibrium in a Korean population and compare them with those of other ethnic groups. Methods: Genotypes of the SULT1A1*1, *2, and *3 and SULT1A2*1, *2, and *3 allelic variants were determined in 234 Korean subjects using polymerase chain reaction (PCR)–restriction fragment length polymorphism (RFLP) methods. Results: Allele frequencies for SULT1A1*1 and *2 were 0.876 [95% confidence interval (CI), 0.843–0.905] and 0.124 (95% CI, 0.096–0.157), respectively. Similarly, those for SULT1A2*1 and *2 were 0.885 (95% CI, 0.852–0.912) and 0.115 (95% CI, 0.088–0.150), respectively. However, no subject with SULT1A1*3 or SULT1A2*3 was detected. These genotype distributions are similar to those of Asian populations including the Chinese and Japanese, but quite different from other ethnic groups such as African-Americans and Caucasians. The expected allelic frequencies of SULT1A1 and SULT1A2 at Hardy–Weinberg equilibrium are quite similar to the observed distributions in the population. SULT1A1*2 and SULT1A2*2, the most common variant alleles of these two genes, are strongly and positively linked in the Korean population (D′=0.8919, χ² =343.24, P=0.0034). Conclusions: SULT1A1*2 and SULT1A2*2 are the major allelic variants in the Korean population, whereas the SULT1A1*3 and SULT1A2*3 alleles were not found. SULT1A1*2 and SULT1A2*2 are strongly linked.     

hOGG1基因多态性与胃癌遗传易感性的关系

目的探讨人类8-羟基鸟嘌呤DNA糖苷酶1（hOGG1）基因多态性与胃癌遗传易感性的关系。方法收集河南郑州和开封地区98例胃癌患者和80例非肿瘤对照组志愿者外周血样,应用聚合酶链反应一限制性片段长度多态性（PCR—RFLP）检测法检测胃癌人群的外周血中DNA损伤修复酶基因多态性,分析其与肿瘤遗传易感性的关系。结果hOGGISer326Cys基因的各基因型频率在胃癌组和对照组间的分布差异有统计学意义（P〈0．05）。携带Cys326Cys基因型者胃癌的发病风险增加1．7倍（OR=I．706,95％CI=0．341～2．462,P=0．002）。hOGGlSer326Cys基因多态性与酒的交互作用增加胃癌的发病风险（S〉1,API=0．38）。结论Cys326Cys基因型是胃癌发病的危险基因型,携带Cys易感基因与饮酒交互作用时可能增加患胃癌的易感性。     

Effect of <Emphasis Type="Italic">MDR1</Emphasis> C3435T polymorphism on lansoprazole in healthy Japanese subjects

Background and aims  The effect of multidrug resistance transporter gene 1 (MDR1) on the bioavailability and kinetics of several substrates has not yet been fully elucidated. We evaluated the influence of MDR1 C3435T polymorphism on the pharmacokinetics and pharmacodynamics of lansoprazole in Japanese subjects. Methods  Fifteen healthy volunteers with the rapid extensive metabolizer genotype of CYP2C19 were classified into three MDR1 C3435T genotype groups: C/C (n = 5), C/T (n = 5), and T/T (n = 5). Lansoprazole 30 mg was administered orally for 15 days. The intragastric pH and plasma lansoprazole levels were determined on days 1 and 15. Results  On day 1, the mean C_max of lansoprazole in the T/T group was significantly higher than that in the C/C or C/T groups (T/T 1,248, C/C 618, C/T 607 ng/ml; P = 0.038). On day 15, similar MDR1 genotype-dependent differences were observed in the C_max of lansoprazole, although smaller than the differences observed on day 1. In contrast, the intragastric pH attained after lansoprazole administration did not differ among MDR1 genotype groups on either day 1 or day 15. Conclusion  Although the sample size was small, our study demonstrated that the MDR1 C3435T polymorphism influenced the pharmacokinetics, but not the pharmacodynamics (i.e., intragastric pH), of lansoprazole in rapid metabolizers of CYP2C19.     

Identification of the Promoter of Human Carbonyl Reductase 3 (<Emphasis Type="BoldItalic">CBR3</Emphasis>) and Impact of Common Promoter Polymorphisms on Hepatic <Emphasis Type="BoldItalic">CBR3</Emphasis> mRNA Expression

Purpose  Recent studies suggest that polymorphisms in human carbonyl reductase 3 (CBR3) influence the pharmacodynamics of doxorubicin. First, we sought to identify the promoter of CBR3. Next, we examined whether two CBR3 promoter polymorphisms (CBR3 -725T>C and CBR3 -326T>A) dictate promoter activity and hepatic CBR3 mRNA levels. Methods  The promoter activities of CBR3 reporter constructs were investigated in HepG2 and MCF-7 cells. CBR3 mRNA levels were documented in 95 liver samples from white (n = 62) and black (n = 33) donors. Genotype-phenotype correlation analyses were used to determine the impact of the CBR3 -725T>C and CBR3 -326T>A polymorphisms on hepatic CBR3 mRNA levels. Results  We identified the promoter of human CBR3. Liver samples from black donors showed higher relative CBR3 mRNA levels than samples from whites (CBR3 mRNA_blacks = 3.0 ± 3.1 relative fold vs. CBR3 mRNA_whites = 1.6 ± 1.5 relative fold, p = 0.021). The variant -725C and -326A alleles did not modify the gene reporter activities of engineered CBR3 promoter constructs. In line, hepatic CBR3 mRNA levels were not associated with CBR3 -725T>C and CBR3 -326T>A genotype status. Conclusions  These studies provide the first insights into the regulation and variable hepatic expression of polymorphic CBR3.     

Prevalence of <Emphasis Type="Italic">UGT1A9</Emphasis> and <Emphasis Type="Italic">UGT2B7</Emphasis> nonsynonymous single nucleotide polymorphisms in West African,Papua New Guinean,and North American populations

Objective UDP-glucuronosyltransferases (UGTs) UGT1A9 and UGT2B7 are involved in the metabolism of antimalarial dihydroartemisinin and antiretroviral zidovudine. Our aim was to analyze the prevalence of UGT1A9 (chromosome 2) and UGT2B7 (chromosome 4) nonsynonymous single nucleotide polymorphisms (SNPs) in West African (WA), Papua New Guinean (PNG), and North American (NA) populations. Methods Using a post-PCR ligation detection reaction-fluorescent microsphere assay, frequencies of UGT1A9 (8G > A, 98T > C, 766G > A) and UGT2B7 (211G > T, 802C > T, 1192G > A) SNPs were determined in WA (n = 133, 5 countries), PNG (n = 153), and NA (n = 350, 4 ethnic groups) individuals. Results The UGT1A9 variant alleles were not common in the study populations. None of the SNPs were present in WA and PNG. Among NA, all 3 SNPs were present (1% each) in Asian-Americans, while 98T > C was present only in Caucasian-Americans (1%) and Hispanic-Americans (1%). Regarding UGT2B7 SNPs, the prevalence of 802C > T was 21% in WA, 28% in PNG, and 28–52% in NA. The SNP 211G > T was present only in Asian-Americans (9%) and Hispanic-Americans (2%), while 1192G > A was not present in any of the subjects. No significant linkage was observed at UGT1A9, UGT2B7, and between both the loci in any of the study populations. Conclusions Taken together, the UGT1A9-UGT2B7 polymorphism profile in WA and PNG populations is similar to African-Americans, but different from Asian-Americans. It is important to determine if these differences, along with previously reported differences in cytochrome P450 2B6 allele frequencies, are associated with altered metabolism/effectiveness of artemisinin drugs. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

Genotype and allele frequencies of polymorphic <Emphasis Type="Italic">CYP2E1</Emphasis> in the Turkish population

Cytochrome P4502E1 (CYP2E1) gene shows genetic polymorphisms that vary markedly in frequency among different ethnic and racial groups. We studied the genotype distributions and allele frequencies of three CYP2E1 polymorphisms: CYP2E1*5B (RsaI/PstI RFLP, C-1053T/G-1293C SNP, rs2031920 /rs3813867), CYP2E1*6 (DraI RFLP, T7632A SNP, rs6413432), and CYP2E1*7B (DdeI RFLP, G-71T SNP, rs6413420) by PCR/RFLP technique in a sample of 206 healthy subjects representing Turkish population. CYP2E1*5B polymorphism analysis yielded the genotype distribution as 96.12% for *1A/*1A (c1/c1), and 3.88% for *1A/*5B (c1/c2). The genotype frequencies for CYP2E1*6 polymorphism were found as 83.98% for *1A/*1A (T/T), 15.53% for *1A/*6 (T/A) and 0.49% for *6/*6 (A/A). For CYP2E1*7B (G-71T) polymorphism, the genotype frequencies were determined to be 86.89% for *1A/*1A (G/G), 12.62% for *1A/*7B (G/T) and 0.49% for *7B/*7B (T/T). Accordingly, the allele frequencies for *5B, *6 and *7B were 1.94, 8.25, and 6.80%, respectively. The genotype distributions of CYP2E1*5B and *6 in Turkish population were similar to those in other Caucasian populations, while differed significantly from East Asian populations. Recently, a novel and functionally important CYP2E1*7B polymorphism was identified in the promoter region. There have been few studies and limited data on CYP2E1*7B polymorphism frequency in the world and, so far, no information has been available for Turkish population. The genotype frequencies of CYP2E1*7B in Turkish population were found to be similar to those of other Caucasian populations. Population studies like this could be useful in assessing the susceptibility of different populations to chemical-induced diseases, including several types of cancer. An account of this work has been presented at the 31st Federation of European Biochemical Societies (FEBS) Congress, in Istanbul, Turkey, on June 24–29, 2006.     

Effects of <Emphasis Type="Italic">CYP3A5, MDR1</Emphasis> and <Emphasis Type="Italic">CACNA1C</Emphasis> polymorphisms on the oral disposition and response of nimodipine in a Chinese cohort

Purpose  Our objective was to study the effects of polymorphic the CYP3A5 (allele *1 and *3), MDR1 [single nucleotide polymorphisms (SNPs) G2677T, C3435T] and CACNA1C (SNPs rs2239128, rs2239050, rs2238032) genes on nimodipine oral disposition and response in healthy Chinese subjects. Methods  Pharmacokinetics and pharmacodynamics data were obtained from a bioequivalence study, and the same 20 subjects were genotyped for CYP3A, MDR1 and CACNA1C. An additional 41 healthy Chinese subjects were recruited to obtain an indication of the distribution of CACNA1C polymorphisms in the Chinese population. Racial differences in the frequency of CACNA1C alleles were assessed. The phenotype differences between genotypes were analyzed. Results  The allelic frequencies of rs2239050 and rs2238032 in our Chinese cohort were different from those in a Caucasian population (p < 0.01). Subjects with mutant alleles (*3/*3) of the CYP3A5 gene had a decreased oral clearance of nimodipine, with a higher lnC_max or compared with those subjects with the heterozygote (*1/*3) or wild type (*1/*1) gene. The CACNA1C rs2239128 C and rs2239050 G SNPs were associated with a stronger efficacy compared with their respective alleles, rs2239128 T and rs2239050 C. MDR1 polymorphisms showed no significance in terms of nimodipine disposition. Conclusions  The polymorphic CYP3A5 (allele *1 and *3) and CACNA1C genes have effects on nimodipine oral disposition and response in healthy Chinese subjects. The homozygous variant of CYP3A5 (*3/*3) was associated with significantly increased nimodipine exposure. CACNA1C SNPs rs2239128 C and rs2239050 G were associated with a stronger efficacy.     

Distribution of <Emphasis Type="Italic">TPMT</Emphasis> risk alleles for thioupurine toxicity in the Israeli population

Background and objective  Individuals with intermediate or no thiopurine S-methyltransferase (TPMT) activity are at risk of hematotoxicity when treated with standard doses of thiopurines, thus, pretreatment identification of these individuals is of major importance. The purpose of this study was to determine the frequency and distribution of TPMT polymorphic variants, known to functionally impair TPMT activity, in the highly heterogeneous Israeli population. Methods   TPMT genotyping of individuals representing three major demographic groups in Israel was carried out by PCR restriction fragment length polymorphism and high-resolution melting. Results  Frequencies of TPMT risk alleles differed significantly among the screened Israeli subpopulations: Druze showed fivefold and twofold higher frequencies than Jews and Moslems, respectively. Specifically, allelic frequencies of TPMT*3A were 0.73% (95% CI 0.34-1.45%), 0.79% (95% CI 0.16-2.39%), and 3.19% (95% CI 1.78-5.58%) in Jews, Moslems, and Druze, respectively. Although not found in Jews, TPMT*3C was found at an allelic frequency of 1.05% (95% CI 0.31-2.76%) and 0.75% (95% CI 0.02-2.84%) in Moslems and Druze. TPMT*2 and TPMT*3B were not detected in any of the Israeli subpopulations studied. Conclusion  These data indicate that the Israeli population displays a distinct TPMT genetic variability that is comprised of a mix of three major genetically diverse subpopulations, each with its unique TPMT allelic frequency distribution pattern and likelihood of developing an adverse reaction to thiopurine drugs.