Involvement of the XRCC1 Arg399Gln gene polymorphism in the development of cervical carcinoma

Elucidation of Increased Cervical Cancer Risk Due to Polymorphisms in XRCC1 (R399Q and R194W), ERCC5 (D1104H), and NQO1 (P187S)

Genetic variations like single nucleotide polymorphisms (SNPs) are associated with cervical carcinogenesis. In this study, SNPs have been identified that contribute toward changes in the function and stability of the proteins and show association with cervical cancer. Initially, literature mining identified 114 protein-coding polymorphisms with population-based evidence in cervical cancer. Subsequently, the functional assessment was performed using sequence-dependent tools, and thereafter, protein stability was analyzed using sequence and structural data. Twenty-three non-synonymous SNPs (nsSNPs) found to be damaging and destabilizing were then analyzed to check their risk association at the population level. The meta-analysis indicated that polymorphisms in DNA damage repair genes XRCC1 (rs25487 and rs1799782), ERCC5 (rs17655), and oxidative stress-related gene NQO1 (rs1800566) are significantly associated with increased cervical cancer risk. The XRCC1 rs25487 and rs1799782 polymorphisms showed the highest risk of cervical cancer in the homozygous model having odds ratio (OR) = 1.85, 95% confidence interval (CI) = 1.17-2.92, p = 0.01, and recessive model with OR = 1.81, 95% CI = 1.01-3.24, and p = 0.04 respectively. Similarly, rs17655 polymorphism of ERCC5 and rs1800566 polymorphism of NQO1 showed the highest pooled OR in the homozygous (OR = 1.70, 95% CI = 1.32-2.19, p = 0.00004) and heterozygous model (OR = 1.3, 95% CI = 1.06-1.58, p = 0.01) respectively. Thus, in this study, a comprehensive collection of nsSNPs was collated and assessed, leading to the identification of polymorphisms in DNA damage repair and oxidative stress-related genes, that destabilize the protein and shows increased risk associated with cervical cancer.

Genetic polymorphisms in DNA repair genes and their association with risk of cervical cancer: A systematic review and meta-analysis

BACKGROUND

There have been a large number of epidemiologic studies regarding the association between genetic polymorphisms in DNA repair genes and onset of cervical cancer. However, results are inconsistent.

METHODS

Articles published before June 2021 and regarding genetic polymorphisms in DNA repair genes and cervical cancer were searched in following databases: PubMed, Web of Science, Google Scholar, and CNKI. With at least three articles for each polymorphism, we made meta-analysis to compute multivariate odds ratios (ORs) and their 95% confidence intervals (CIs).

RESULTS

The present study showed significant associations between XRCC1 Arg399Gln polymorphisms and risk of cervical cancer in Asian, whereas no significant association between them were showed in Caucasian (Asian: GA vs. GG: OR = 1.27, 95%CI 1.06-1.52; AA vs. GG: OR = 1.91, 95%CI 1.29-2.83; GA + AA vs. GG: OR = 1.36, 95%CI 1.12-1.65; AA vs. GG + GA: OR = 1.66, 95%CI 1.17-2.37; Caucasian: GA vs. GG: OR = 1.08, 95%CI 0.83-1.41; AA vs. GG: OR = 2.18, 95%CI 0.75-6.31; GA + AA vs. GG: OR = 1.23, 95%CI 0.85-1.78; AA vs. GG + GA: OR = 1.70, 95%CI 0.69-4.18). In addition, there were significant associations between ERCC2 rs13181 polymorphisms and risk of cervical cancer in Asian (AC vs AA: OR = 0.53, 95%CI 0.37-0.75, I²  = 0.0%, p value of Q test = 0.847; AC + CC vs AA: OR = 0.50, 95%CI 0.36-0.70, I²  = 0.0%, p value of Q test = 0.856).

CONCLUSIONS

The meta-analysis showed that there were significant associations between XRCC1 Arg399Gln and ERCC2 rs13181 polymorphisms and risk of cervical cancer.

A meta-analysis of XRCC1 single nucleotide polymorphism and susceptibility to gynecological malignancies

BACKGROUND

Gynecological malignant tumor is a serious threat to women's health, cervical cancer, endometrial cancer and ovarian cancer are the most common. The eponymous protein encoded by the XRCC1 (X-ray repair cross complementation 1) gene is an important functional protein in the process of single-stranded DNA damage. Non-synonymous mutations of XRCC1 gene cause amino acid sequence changes that affect protein function and DNA repair ability, and may affect the interaction with other DNA repair proteins, leading to increased risk of tumor development. Many studies have assessed the association between XRCC1 gene polymorphism and the risk of cancer in the female reproductive system, but the results have been inconclusive. In this study, the relationship between XRCC1 Arg399Gln, Arg194Trp, Arg280His single nucleotide polymorphisms and susceptibility to gynecological malignancies was further explored by meta-analysis.

METHODS

English database: Pubmed, Medline, Excerpta Medica Database, Cochrance, etc; Chinese database: China national knowledge infrastructure, Wanfang Database, etc. STATA14 was used for statistical analysis, such as odd ratio (OR) value, subgroup analysis, heterogeneity test, sensitivity analysis, and publication bias.

RESULTS

In gynecologic cancers, the allele frequency difference of Arg399Gln case control group was statistically significant (GvsA: P = .007). There was no significant difference in allele frequency in the Arg194Trp and Arg280His case control groups (P = .065, 0.198). In different gene models, Arg399Gln was significantly correlated with gynecologic cancers susceptibility (GGvs AA: OR 0.91; 95% confidence interval [CI], 0.85 0.98); Arg194Trp was significantly correlated with gynecologic cancers susceptibility (CCvs TT: OR 0.94; 95% CI 0.88,1.00; CCvs CT: OR 0.97; 95% CI 0.90, 1.05); Arg280His was significantly correlated with gynecologic cancers susceptibility (GGvs AA: OR 0.98; 95% CI 0.94, 1.02; GGvs GA: OR 1.00;95% CI 0.97, 1.04). In the subgroup analysis, Arg399Gln and Arg194Trp were significantly correlated with gynecologic cancers susceptibility in the Asian race (P = .000, 0.049). In the analysis of different cancer subgroups, Arg399Gln and cervical cancer susceptibility were statistically significant (P = .039). Arg194Trp and endometrial cancer susceptibility were statistically significant (P = .033, 0.001).

CONCLUSIONS

XRCC1 Arg399Gln, Arg194Trp, Arg280His single nucleotide polymorphisms were associated with gynecologic cancer susceptibility. Arg399Gln genotype was statistically significant in relation to cervical cancer susceptibility. Arg194Trp genotype was statistically significant in relation to endometrial cancer susceptibility.

The scaffold protein XRCC1 stabilizes the formation of polβ/gap DNA and ligase IIIα/nick DNA complexes in base excision repair

The base excision repair (BER) pathway involves gap filling by DNA polymerase (pol) β and subsequent nick sealing by ligase IIIα. X-ray cross-complementing protein 1 (XRCC1), a nonenzymatic scaffold protein, assembles multiprotein complexes, although the mechanism by which XRCC1 orchestrates the final steps of coordinated BER remains incompletely defined. Here, using a combination of biochemical and biophysical approaches, we revealed that the polβ/XRCC1 complex increases the processivity of BER reactions after correct nucleotide insertion into gaps in DNA and enhances the handoff of nicked repair products to the final ligation step. Moreover, the mutagenic ligation of nicked repair intermediate following polβ 8-oxodGTP insertion is enhanced in the presence of XRCC1. Our results demonstrated a stabilizing effect of XRCC1 on the formation of polβ/dNTP/gap DNA and ligase IIIα/ATP/nick DNA catalytic ternary complexes. Real-time monitoring of protein–protein interactions and DNA-binding kinetics showed stronger binding of XRCC1 to polβ than to ligase IIIα or aprataxin, and higher affinity for nick DNA with undamaged or damaged ends than for one nucleotide gap repair intermediate. Finally, we demonstrated slight differences in stable polβ/XRCC1 complex formation, polβ and ligase IIIα protein interaction kinetics, and handoff process as a result of cancer-associated (P161L, R194W, R280H, R399Q, Y576S) and cerebellar ataxia-related (K431N) XRCC1 variants. Overall, our findings provide novel insights into the coordinating role of XRCC1 and the effect of its disease-associated variants on substrate-product channeling in multiprotein/DNA complexes for efficient BER.

Significance of base excision repair to human health

Oxidative and alkylating DNA damage occurs under normal physiological conditions and exogenous exposure to DNA damaging agents. To counteract DNA base damage, cells have evolved several defense mechanisms that act at different levels to prevent or repair DNA base damage. Cells combat genomic lesions like these including base modifications, abasic sites, as well as single-strand breaks, via the base excision repair (BER) pathway. In general, the core BER process involves well-coordinated five-step reactions to correct DNA base damage. In this review, we will uncover the current understanding of BER mechanisms to maintain genomic stability and the biological consequences of its failure due to repair gene mutations. The malfunction of BER can often lead to BER intermediate accumulation, which is genotoxic and can lead to different types of human disease. Finally, we will address the use of BER intermediates for targeted cancer therapy.

Association between XRCC3 Thr241Met polymorphism and risk of gynecological malignancies: A meta-analysis

Studies have investigated the relationship between the X-ray cross- complementing group 3 (XRCC3) Thr241Met polymorphism and the risk of gynecological malignancies (GM) with the contradictory conclusions. Here, a meta-analysis was performed to provide clear picture of the association between Thr241Met and GM risk. The Pubmed and Chinese National Knowledge Infrastructure (CNKI) databases were searched for published eligible studies. The pooled odds ratios (OR) with their corresponding 95% confidence interval (CI) was used to assessed the strength of association. Totally, 15 publications with 5,740 cases and 9,931 controls were included. In the overall analysis, the results of meta-analysis showed no significant association between the Thr241Met and the risk of GM. However, in the Asians subgroup, significant increased risks were found in the comparisons of TT/CT+TT vs. CC(TT vs. CC: OR=3.25, 95% CI=1.47-7.18; CT+TT vs. CC: OR=1.51, 95%CI=1.10-2.09) in Asians; additionally, stratified analysis by cancer type in Asians, significantly increased risks was found in cervical carcinoma (CT vs. CC: OR=1.50, 95%CI=1.04-2.14; TT vs. CC: OR=3.14, 95%CI=1.38-7.14; CT+TT vs. CC: OR=1.64, 95% CI=1.17-2.31). It suggests that the risk of GM might be significantly increased by the XRCC3 Thr241Met polymorphism according to ethnicity and cancer types. Further studies with larger sample size in different ethnic populations and different sites of GM are needed to verify the findings.

Meta-analysis of XRCC1 polymorphism and risk of female reproductive system cancer

Numerous epidemiological studies have evaluated the association between polymorphism in the gene encoding x-ray repair cross complementing 1 (XRCC1) protein and the risk of female reproductive system cancer, but results are inconclusive. To gain a comprehensive picture of available evidence, we searched for relevant studies in the PubMed, EMBASE, Scopus, and Chinese National Knowledge Infrastructure databases up to December 17, 2016. A total of 26 case-control studies were picked out. The pooled odds ratio (OR) with its 95% confidence interval (CI) was calculated to estimate the association. Based on data of all study participants, we did not find a positive association of rs25487 or rs1799782 polymorphism with risk of female reproductive cancer risk. Subgroup analysis, however, identified two alleles as being associated with an increased risk of female reproductive system cancer in Asians: the A allele of rs25487 (heterozygous genetic model, OR 1.16, 95%CI 1.00-1.36), and the T allele of rs1799782 (homozygous model, OR 2.30, 95%CI 1.39-3.82; dominant model, OR 1.28, 95%CI 1.10-1.50; recessive model, OR 2.11, 95%CI 1.33-3.34). Moreover, the AA genotype at rs25489 was determined to be a risk factor for cervical cancer etiology (homozygous model, OR 2.91, 95%CI, 1.17-7.26; recessive model, OR 3.16, 95%CI 1.91-5.24). This meta-analysis suggests that no association between rs25487 or rs1799782 gene polymorphism and risk of female reproductive cancer risk was found. These results should be validated in larger studies.

Association between XRCC1 polymorphisms and the risk of cervical cancer: a meta-analysis based on 4895 subjects

The present meta-analysis was intended to explore the relationship between the X-ray repair cross complementing 1 (XRCC1) polymorphisms (Arg194Trp, Arg280His and Arg399Gln) and cervical cancer risk. Several electronic databases were searched systematically and bibliographies of relevant papers were identified carefully. Then, a meta-analysis was performed based on eligible studies in various genetic models. Pooled odds ratios (OR) with 95% confidence intervals (95% CI) were employed to evaluate the strength of associations between the XRCC1 polymorphisms and cervical cancer risk. Additionally, heterogeneity analysis and sensitivity analysis were done if necessary. Totally, 11 articles involving 2092 cases and 2803 controls were included. Taken together, there was no obvious association between the Arg194Trp or Arg280His polymorphism and cervical cancer risk. Considering the great heterogeneity, subgroup analysis was done, but the pooled result remained stable. Nevertheless, the association between the Arg399Gln polymorphism and cervical cancer risk showed distinct statistic significance in the allele model, dominant model, homozygous model and heterozygous model. In view of the exiting heterogeneity, we did subgroup analysis stratified by ethnicity, resulting in the fact that the Arg399Gln polymorphism was related to the decreased risk of cervical cancer. The Begg's test and Egger's test were used to find no publication bias. To conclude, the current meta-analysis indicated that the XRCC1 Arg399Gln polymorphism decreased the risk of cervical cancer, while the Arg194Trp and Arg280His polymorphisms were not associated with cervical caner risk. Certainly, a well-designed large-scale multicenter study is warranted to confirm the finding.

Environmental exposure and HPV infection may act synergistically to induce lung tumorigenesis in nonsmokers

Most studies of lung tumorigenesis have focused on smokers rather than nonsmokers. In this study, we used human papillomavirus (HPV)-positive and HPV-negative lung cancer cells to test the hypothesis that HPV infection synergistically increases DNA damage induced by exposure to the carcinogen benzo[a]pyrene (B[a]P), and contributes to lung tumorigenesis in nonsmokers. DNA adduct levels induced by B[a]P in HPV-positive cells were significantly higher than in HPV-negative cells. The DNA adduct formation was dependent on HPV E6 oncoprotein expression. Gene and protein expression of two DNA repair genes, XRCC3 and XRCC5, were lower in B[a]P-treated E6-positive cells than in E6-negative lung cancer cells. The reduced expression was also detected immunohistochemically and was caused by increased promoter hypermethylation. Moreover, mutations of p53 and epidermal growth factor receptor (EGFR) genes in lung cancer patients were associated with XRCC5 inactivation. In sum, our study indicates that HPV E6-induced promoter hypermethylation of the XRCC3 and XRCC5 DNA repair genes and the resultant decrease in their expression increases B[a]P-induced DNA adducts and contributes to lung tumorigenesis in nonsmokers.

DNA repair genes XRCC1 and ERCC1 polymorphisms and the risk of sporadic breast cancer in Han women in the Gansu Province of China

AIMS

Polymorphisms in DNA damage repair genes may affect DNA repair capacity and modulate breast cancer susceptibility. In this study, we aimed to analyze two polymorphisms for each of the DNA repair genes X-ray repair cross-complementing group 1 (XRCC1) rs25487 and rs1799782 and excision repair cross-complementing group 1 (ERCC1) rs3212964 and rs11615, to evaluate their associations with the risk of sporadic breast cancer in Han women in the Gansu Province of China.

METHODS

Genotypes were determined by a polymerase chain reaction-based approach for 101 patients with breast cancer and in 101 disease-free controls.

RESULTS

We found that individuals with the AA genotype at XRCC1 rs25487 had a significantly increased risk of breast cancer compared with GG genotype (p<0.001, odds ratio [OR]=6.39, 95% confidence interval [CI]: 2.18-18.65). The dominant model showed that the combined rs25487 genotypes (AA+AG) increased the disease risk (p<0.001, OR=3.17, 95% CI: 1.76-5.72). However, no statistical associations were found between rs1799782 in XRCC1, or rs3212964 and rs11615 in ERCC1 and the risk of disease. In haplotype analysis, the GC haplotype in XRCC1 conferred an increased risk (p<0.001) with a 4.78-fold increase for each copy (95% CI: 2.52-8.72). Significant associations were also shown between the single nucleotide polymorphisms (SNPs) and the status of estrogen receptor (ER), progesterone receptor (PR), and HER-2.

CONCLUSIONS

The results suggest that the XRCC1 rs25487 polymorphism may increase the risk of breast cancer.

HPV-16 E2 physical status and molecular evolution in vivo in cervical carcinomas

A key event in the development of cervical carcinoma is the deregulated expression of high-risk human papillomavirus (HR-HPV) oncogenes, most commonly due to HPV integration into host DNA. Here we explored whether HPV-16 E2 gene integrity is a biomarker of progressive disease with oncogenes expression. HPV-16 genome disruption was assessed by amplification of the entire E2 gene, while mRNA expression patterns of the E1, E2, E6, and E7 genes were evaluated by reverse transcription PCR (RT-PCR). As expected, E2 disruption was significantly higher among patients with cervical cancers than subjects with benign lesions (p=0.02). The status of the E2 gene correlated with tumorogenesis, and seemed also to correlate with the stage of the carcinomas, since integrated HPV-16 DNA was frequently detected in patients with advanced cancer stages (75% of stage III vs 60% stages I and II). In bivariate analysis, the lesions&rsquo; grade was most significantly associated with HPV-16 DNA disruption (p&lt;0.05). In cervical carcinoma the deletion pattern involved more frequently the E2 gene rather than the E1 gene (62.5% vs 45.8%). The prevalence of the E6/E7 HPV-16 transcripts in cervical carcinoma specimens and in benign cervical lesions were detected with frequencies of, respectively, 91.6% and 45.4%. The mRNA levels of the HPV-16 E6/E7 genes were expressed at approximately the same levels in each physical state. We consistently observed that E6/E7 were absent or weakly detectable in the presence of E2. However, in the absence of E2 the levels of E6/E7 markedly increased (p&lt;0.05). This study underscores the significance of investigating alternative mechanisms of E2 expression and oncogenes E6/E7 transcripts in vivo as biomarkers for disease severity in cervical carcinomas.

Association of genetic variations in X-ray repair cross-complementing group 1 and Tourette syndrome

BACKGROUND

X-ray repair cross-complementing group 1 (XRCC1) plays a central role in mammalian DNA repair process. The polymorphism rs25487 (Arg>Gln at codon 399) of this gene is common in Han Chinese population.

OBJECTIVES

The objective of this study was to analyze the association between this functional SNP of XRCC1 and Tourette syndrome (TS) in Han Taiwan Chinese population.

METHODS

Genotyping was performed by using PCR-RFLP method on 73 TS patients and 158 normal controls.

RESULTS

Our data indicated that genotype frequency of A/G polymorphism at codon 399 of the patients differed from the controls (P = 0.026, OR: 2.22, 95% CI: 1.22-4.03). The allele frequency analysis also showed significant differences with higher A allele frequency in patients (P = 0.015, OR: 1.70, 95% CI: 1.11-2.62).

CONCLUSION

Our study indicates that the functional SNP at codon 399 of XRCC1 is associated with TS development.

X-ray repair cross-complementing group 1 (XRCC1) genetic polymorphisms and cervical cancer risk: a huge systematic review and meta-analysis

BACKGROUND

Previous studies investigating the association between X-ray repair cross-complementation group 1(XRCC1) polymorphisms and cervical cancer (CC) risk has provided inconsistent results. The aim of our study was to assess the association between the XRCC1 gene Arg399Gln, Arg194Trp, Arg280His polymorphisms and risk of CC.

METHODS

Two investigators independently searched the Medline, Embase, CNKI, and Chinese Biomedicine Databases for studies published before March 2011.Summary odds ratios (ORs) and 95% confidence intervals (CIs) for XRCC1 polymorphisms and CC were calculated in a fixed-effects model or a random-effects model when appropriate.

RESULTS

Ultimately, 9, 5 and 2 studies were found to be eligible for meta-analyses of Arg399Gln, Arg194Trp and Arg280His, respectively. Our analysis suggested that the variant genotypes of Arg194Trp were associated with a significantly increased CC risk (Trp/Trp vs Arg/Arg, OR = 2.21, 95% CI = 1.60-3.06; Arg/Trp vs Arg/Arg, OR = 1.23, 95% CI = 1.02-1.49; dominant model, OR = 1.36, 95% CI = 1.14-1.63; recessive model, OR = 2.06, 95% CI = 1.51-2.82). For Arg280His polymorphism, no obvious associations were found for all genetic models. For Arg399Gln polymorphism, also no obvious associations were found for all genetic models. In the subgroup analyses by ethnicity/country, a significantly increased risk was observed among Asian, especially among Chinese. To get more precise evidences, adjusted ORs (95%CI) by potential confounders (such as age, ethnicity or smoking, etc) were also calculated for XRCC1 Arg399Gln and Arg194Trp, however, the estimated pooled adjusted OR still did not change at all.

CONCLUSION

This meta-analysis suggests that Arg194Trp polymorphism may be associated with CC risk, Arg399Gln polymorphism might be a low-penetrent risk factor for CC only in Asians, and there may be no association between Arg280His polymorphism and CC risk.

Base excision repair and cancer

Base excision repair is the system used from bacteria to man to remove the tens of thousands of endogenous DNA damages produced daily in each human cell. Base excision repair is required for normal mammalian development and defects have been associated with neurological disorders and cancer. In this paper we provide an overview of short patch base excision repair in humans and summarize current knowledge of defects in base excision repair in mouse models and functional studies on short patch base excision repair germ line polymorphisms and their relationship to cancer. The biallelic germ line mutations that result in MUTYH-associated colon cancer are also discussed.