DNA repair gene X-ray repair cross complementing group 1 Arg194Trp polymorphism on the risk of lung cancer: a meta-analysis on 22 studies

The association of XRCC1 polymorphism with osteosarcoma risk, clinicopathologic features, and prognosis in a Chinese Han population

Introduction

The association of single-nucleotide polymorphisms at X-ray repair cross-complementing group-1 (XRCC1) with osteosarcoma (OS) development has not been fully clear to date. The aim of the present study is to evaluate the association of XRCC1 polymorphisms with risk, clinicopathologic features, and prognosis in Chinese OS patients.

Methods

A total of 146 patients with primary OS and 248 age- and gender-matched controls were included in the present study. The frequencies of four XRCC1 polymorphisms (rs25487, rs1799782, rs25489, and rs3213245) were determined between OS patients and controls. The association of XRCC1 polymorphism with clinicopathologic characteristics, prognosis, and XRCC1 expression was further evaluated.

Results

Compared with TT genotype, individuals carrying the minor C allele (TC+ CC) of rs3213245 had significantly increased risk of OS development (OR =1.83, 95% CI 1.14–3.00). OS patients carrying TC genotype and C allele at rs3213245 were more likely to be with larger tumor size and metastasis. Survival analysis demonstrated that OS patients carrying C allele (TC + CC) at rs3213245 had shorter survival time than those with TT genotype. The T to C substitution at rs3213245 could decrease XRCC1 gene transcriptional activity in vitro. XRCC1 mRNA and protein expression levels were lower in OS patients carrying TC or CC genotype at rs3213245. Besides, no significant association of rs25487, rs1799782, and rs25489 with OS was observed.

Conclusion

In conclusion, these findings revealed that XRCC1 rs3213245 polymorphism was associated with increased risk of OS, which could affect XRCC1 expression in vitro and in vivo.

Arg194–Arg399 haplotype of XRCC1 gene is susceptible to lung cancer in the Han population

Objective:

Lung cancer is still one of the most frequently diagnosed cancers all over the world, especially in developing countries. The aim of this study was to investigate the relationship between two well-characterized non-synonymous polymorphisms (Arg194Trp and Arg399Gln) in X-ray repair cross-complementing group 1 ( XRCC1) gene and the risk of lung carcinoma in the Han population.

Methods:

This study was hospital-based in design and included 159 participants (63 patients with lung carcinoma and 96 cancer-free controls) of Chinese Han descent. Genomic DNA from blood samples was extracted for PCR studies, followed by direct sequencing to determine the variants of the XRCC1 gene.

Results:

Carriers with Arg194–Arg399 haplotype of XRCC1 gene conferred a 189.3% increased risk compared to the non-carriers (95% confidence interval [CI], 1.195–2.998; P = 0.006). And single-locus analysis (both allele and genotype distributions of polymorphism Arg194Trp and Arg399Gln) identified neither association with cancer risk nor with clinico-pathological parameters of lung carcinoma in the Han population.

Conclusions:

Arg194–Arg399 haplotype of XRCC1 gene might increase lung cancer susceptibility and serve as a risk factor for lung cancer in the Han population.

DNA repair pathway genes and lung cancer susceptibility: a meta-analysis

OBJECTIVE

DNA repair pathway genes have been implicated to play an important role in the development of lung cancer. However, contradictory results are often reported by various studies, making it difficult to interpret them. So in this meta-analysis, we have assessed the association between lung cancer risk and two DNA repair pathway genes. XRCC1 and ERCC2, by analyzing 67 published case-control studies.

RESEARCH DESIGN AND METHODS

We searched PubMed, Embase and Web of Science using terms "XRCC1" or "XPD" or "ERCC2" and "lung cancer" on August 1, 2012. Three criteria were applied to select included studies for resulting studies. Information was carefully extracted by two investigators independently. We used pooled odds ratio (OR) to assess the effect of a polymorphism, and a dominant model was applied where genotypes that contain the non-reference allele were combined together. All the calculations were performed using STATA version 11.0.

MAIN OUTCOME MEASURES AND RESULTS

Three common nonsynonymous polymorphisms in XRCC1, codon 194, codon 280 and codon 399, and two common nonsynonymous polymorphisms in ERCC2, codon 312 and codon 751, were analyzed. The result showed in total population, Lys751Gln in ERCC2 is associated with an increase of lung cancer risk, with a summary OR as 1.15. No association was found for any other polymorphisms. When studies were stratified by ethnicity, the risk effect of Lys751Gln in ERCC2 was found only in Caucasians, not in Asians.

CONCLUSIONS

In conclusion, Lys751Gln in ERCC2 is associated with lung cancer, and the risk effect probably exists in Caucasians. By contrast, polymorphisms in XRCC1 are less likely to be susceptible to lung cancer risks.

XRCC1 Arg399Gln, Arg194Trp, and Arg280His polymorphisms in esophageal cancer risk: a meta-analysis

BACKGROUND

The X-ray repair cross-complementation group 1 (XRCC1) protein plays an important role in base excision repair.

AIM

To elucidate the role of XRCC1 Arg399Gln, Arg194Trp and Arg280His genotypes in esophageal cancer risk, all available studies were considered in the present meta-analysis.

METHODS

Eligible studies were identified by searching several electronic databases for relevant reports published before June 2012.

RESULTS

According to the inclusion criteria and exclusion criteria, a total of 21 eligible studies were included in the pooled analyses. Among the 21 studies, 18 focused on Arg399Gln polymorphism, 11 described the Arg194Trp, and 4 articles investigated on Arg280His. Our analysis suggested that there was no evidence of significant association between XRCC1 Arg399Gln polymorphism and esophageal cancer risk in any genetic model. In the stratified analysis by ethnicity for Arg399Gln polymorphism and esophageal cancer, the results showed that Arg399Gln polymorphism was not associated with esophageal cancer risk. Only 4 studies analyzed the relationship between XRCC1 Arg280His polymorphism and the risk of esophageal cancer. The Arg/His and His/His genotypes were not significantly associated with increased risk of EC. A similar negative association was maintained in dominant and recessive models. However, for XRCC1 Arg194Trp polymorphism, our study showed individuals carrying the variant genotype Trp/Trp had a significant increased risk of esophageal cancer (OR = 1.295, 95 % CI 1.053-1.591, P = 0.014). In addition, increased associations were found in recessive model (OR = 1.332, 95 % CI 1.093-1.624, P = 0.005).

CONCLUSIONS

Our meta-analysis suggested that Arg194Trp Trp allele might act as a risk allele in its association with esophageal cancer.

Association between the XRCC1 polymorphisms and glioma risk: a meta-analysis of case-control studies

Background

X-ray repair cross-complementing group 1 (XRCC1) is one of the DNA repair genes encoding a scaffolding protein that participate in base excision repair (BER) pathway. However, studies on the association between polymorphisms in this gene and glioma have yielded conflicting results. This meta-analysis was performed to derive a more precise estimation between XRCC1 polymorphisms (Arg399Gln, Arg194Trp, and Arg280His) and glioma risk.

Methods

Data were collected from several electronic databases, with the last search up to November 28, 2012. Meta-analysis was performed by critically reviewing 9 studies for Arg399Gln polymorphism (3146 cases and 4296 controls), 4 studies for Arg194Trp polymorphism (2557 cases and 4347 controls), and 4 studies for Arg280His polymorphism (1936 cases and 2895 controls). All of the statistical analyses were performed using the software programs STATA (version 11.0).

Results

The combined results showed that Arg399Gln polymorphism was significantly associated with glioma risk (Gln/Gln versus Arg/Arg: OR = 1.52, 95% CI = 1.03–2.23; recessive model: OR = 1.32, 95% CI = 1.01–1.73; additive model: OR = 1.21, 95% CI = 1.00–1.47), whereas Arg194Trp/Arg280His polymorphisms were all not significantly associated with glioma risk. As for ethnicity, Arg399Gln polymorphism was associated with increased risk of glioma among Asians (Gln/Gln versus Arg/Arg: OR = 1.78, 95% CI = 1.29–2.47; Arg/Gln versus Arg/Arg: OR = 1.28, 95% CI = 1.05–1.56; recessive model: OR = 1.59, 95% CI = 1.16–2.17; dominant model: OR = 1.36, 95% CI = 1.13–1.65; additive model: OR = 1.32, 95% CI = 1.15–1.52), but not among Caucasians. Stratified analyses by histological subtype indicated that the Gln allele of Arg399Gln polymorphism showed borderline association with the risk of glioblastoma among Caucasians. However, no evidence was observed in subgroup analyses for Arg194Trp/Arg280His polymorphisms.

Conclusions

Our meta-analysis suggested that Arg399Gln polymorphism was associated with increased risk of glioma among Asians and borderline increased risk for glioblastoma among Caucasians, whereas Arg194Trp/Arg280His polymorphisms might have no influence on the susceptibility of glioma in different ethnicities.

DNA methyltransferases, DNA damage repair, and cancer

The maintenance DNA methyltransferase (DNMT) 1 and the de novo methyltransferases DNMT3A and DNMT3B are all essential for mammalian development. DNA methylation, catalyzed by the DNMTs, plays an important role in maintaining genome stability. Aberrant expression of DNMTs and disruption of DNA methylation patterns are closely associated with many forms of cancer, although the exact mechanisms underlying this link remain elusive. DNA damage repair systems have evolved to act as a genome-wide surveillance mechanism to maintain chromosome integrity by recognizing and repairing both exogenous and endogenous DNA insults. Impairment of these systems gives rise to mutations and directly contributes to tumorigenesis. Evidence is mounting for a direct link between DNMTs, DNA methylation, and DNA damage repair systems, which provide new insight into the development of cancer. Like tumor suppressor genes, an array of DNA repair genes frequently sustain promoter hypermethylation in a variety of tumors. In addition, DNMT1, but not the DNMT3s, appear to function coordinately with DNA damage repair pathways to protect cells from sustaining mutagenic events, which is very likely through a DNA methylation-independent mechanism. This chapter is focused on reviewing the links between DNA methylation and the DNA damage response.

Association between XRCC1 and XRCC3 polymorphisms and colorectal cancer risk: a meta-analysis of 23 case-control studies

Several potential functional polymorphisms in the DNA repair gene X-ray repair cross-complementing group 1 (XRCC1) Arg399Gln (rs25487), Arg194Trp (rs1799782), Arg280His (rs25489) and X-ray repair cross-complementing group 3 (XRCC3) T241M (rs861539) have been implicated in colorectal cancer (CRC) risk, but the results are conflicting. Here, we performed a meta-analysis of 23 published case control datasets and assessed genetic heterogeneity between those datasets. All the case-control studies published from January 2000 to June 2012 on the association between those polymorphisms and CRC risk were identified by searching the electronic literature Medline. Statistical analysis was performed with the software programs Review Manager (version 4.2). For overall CRC, no significant association was observed, the pooled odds ratios for XRCC1 Arg399Gln, Arg194Trp, Arg280His, and XRCC3 T241M were 1.02 (95 % CI: 0.93, 1.12), 1.03 (95 % CI: 0.94, 1.14), 0.98 (95 % CI: 0.85, 1.13) and 1.03 (95 % CI: 0.85, 1.26), respectively. Furthermore, no significant association was observed in subgroup analyses based on ethnicity. The results suggested that these four SNPs evaluated are not associated with risk of CRC.

X-ray repair cross complementing protein 1 in base excision repair

X-ray Repair Cross Complementing protein 1 (XRCC1) acts as a scaffolding protein in the converging base excision repair (BER) and single strand break repair (SSBR) pathways. XRCC1 also interacts with itself and rapidly accumulates at sites of DNA damage. XRCC1 can thus mediate the assembly of large multiprotein DNA repair complexes as well as facilitate the recruitment of DNA repair proteins to sites of DNA damage. Moreover, XRCC1 is present in constitutive DNA repair complexes, some of which associate with the replication machinery. Because of the critical role of XRCC1 in DNA repair, its common variants Arg194Trp, Arg280His and Arg399Gln have been extensively studied. However, the prevalence of these variants varies strongly in different populations, and their functional influence on DNA repair and disease remains elusive. Here we present the current knowledge about the role of XRCC1 and its variants in BER and human disease/cancer.

Reprint of: gene susceptibility to oxidative damage: from single nucleotide polymorphisms to function

Oxidative damage to DNA can cause mutations, and mutations can lead to cancer. DNA repair of oxidative damage should therefore play a pivotal role in defending humans against cancer. This is exemplified by the increased risk of colorectal cancer of patients with germ-line mutations of the oxidative damage DNA glycosylase MUTYH. In contrast to germ-line mutations in DNA repair genes, which cause a strong deficiency in DNA repair activity in all cell types, the role of single nucleotide polymorphisms (SNPs) in sporadic cancer is unclear also because deficiencies in DNA repair, if any, are expected to be much milder. Further slowing down progress are the paucity of accurate and reproducible functional assays and poor epidemiological design of many studies. This review will focus on the most common and widely studied SNPs of oxidative DNA damage repair proteins trying to bridge the information available on biochemical and structural features of the repair proteins with the functional effects of these variants and their potential impact on the pathogenesis of disease.

XRCC1 gene polymorphisms and lung cancer susceptibility: a meta-analysis of 44 case-control studies

X-ray repair cross-complementing group 1 gene (XRCC1) has been implicated in risk for lung cancer. However, the results from different studies remain controversial. In this meta-analysis, we have assessed 44 published case-control studies regarding associations of lung cancer risk with three common polymorphisms, codon 194, codon 280 and codon 399, and -77 T > C in the promoter region of XRCC1. The results in total population showed that the risk for lung cancer was increased among the variant homozygote Trp/Trp of codon 194 polymorphism, compared with the wild type Arg/Arg (OR: 1.19; 95 % CI 1.01-1.39), and the variant genotype CC of -77 T > C polymorphism showed a significantly increased risk of developing lung cancer, compared to wild-type genotype TT (OR: 1.91; 95 % CI 1.24-2.94). However, no associations were found between lung cancer risk and codon 280, codon 399. In the subgroup analyses by ethnicity, the OR for the variant homozygote Trp/Trp of codon 194 was 1.21(95 % CI 1.02-1.43) for Asian. When stratified by source of control, we found a protective effect of codon 194 Arg/Trp genotype (OR: 0.87; 95 % CI 0.77-0.98) and risk effect of codon 399 combined Arg/Gln + Gln/Gln variant genotype (OR: 1.09; 95 % CI 1.01-1.18) for lung cancer on the basis of hospital control. Subgroup analyses by histological types of lung cancer indicated that the heterozygote Arg/Trp in codon 194 could decrease and the combined variant genotype Arg/Gln + Gln/Gln in codon 399 could increase the risk of non-small cell lung cancer (OR: 0.69; 95 % CI 0.57-0.85 and OR: 1.14; 95 % CI 1.04-1.24). In conclusion, this meta-analysis has demonstrated that codon 194, codon 399 and -77 T > C polymorphisms of XRCC1 gene might have contributed to individual susceptibility to lung cancer. To further evaluate effect of XRCC1 polymorphisms, gene-gene interaction and gene-environment interaction on lung cancer risk, a single large sample size study with thousands of subjects is required to get conclusive results.

Gene susceptibility to oxidative damage: from single nucleotide polymorphisms to function

Oxidative damage to DNA can cause mutations, and mutations can lead to cancer. DNA repair of oxidative damage should therefore play a pivotal role in defending humans against cancer. This is exemplified by the increased risk of colorectal cancer of patients with germ-line mutations of the oxidative damage DNA glycosylase MUTYH. In contrast to germ-line mutations in DNA repair genes, which cause a strong deficiency in DNA repair activity in all cell types, the role of single nucleotide polymorphisms (SNPs) in sporadic cancer is unclear also because deficiencies in DNA repair, if any, are expected to be much milder. Further slowing down progress are the paucity of accurate and reproducible functional assays and poor epidemiological design of many studies. This review will focus on the most common and widely studied SNPs of oxidative DNA damage repair proteins trying to bridge the information available on biochemical and structural features of the repair proteins with the functional effects of these variants and their potential impact on the pathogenesis of disease.

The region of XRCC1 which harbours the three most common nonsynonymous polymorphic variants, is essential for the scaffolding function of XRCC1

XRCC1 functions as a non-enzymatic, scaffold protein in single strand break repair (SSBR) and base excision repair (BER). Here, we examine different regions of XRCC1 for their contribution to the scaffolding functions of the protein. We found that the central BRCT1 domain is essential for recruitment of XRCC1 to sites of DNA damage and DNA replication. Also, we found that ectopic expression of the region from residue 166-436 partially rescued the methyl methanesulfonate (MMS) hypersensitivity of XRCC1-deficient EM9 cells, suggesting a key role for this region in mediating DNA repair. The three most common amino acid variants of XRCC1, Arg194Trp, Arg280His and Arg399Gln, are located within the region comprising the NLS and BRCT1 domains, and these variants may be associated with increased incidence of specific types of cancer. While we could not detect differences in the intra-nuclear localization or the ability to support recruitment of POLβ or PNKP to micro-irradiated sites for these variants relative to the conservative protein, we did observe lower foci intensity after micro-irradiation and a reduced stability of the foci with the Arg280His and Arg399Gln variants, respectively. Furthermore, when challenged with MMS or hydrogen peroxide, we detected small but consistent differences in the repair profiles of cells expressing these two variants in comparison to the conservative protein.

High XRCC1 protein expression is associated with poorer survival in patients with head and neck squamous cell carcinoma

PURPOSE

We evaluated X-ray repair complementing defective repair in Chinese hamster cells 1 (XRCC1) protein in head and neck squamous cell carcinoma (HNSCC) patients in association with outcome.

EXPERIMENTAL DESIGN

XRCC1 protein expression was assessed by immunohistochemical (IHC) staining of pretreatment tissue samples in 138 consecutive HNSCC patients treated with surgery (n = 31), radiation (15), surgery and radiation (23), surgery and adjuvant chemoradiation (17), primary chemoradiation (51), and palliative measures (1).

RESULTS

Patients with high XRCC1 expression by IHC (n = 77) compared with patients with low XRCC1 expression (n = 60) had poorer median overall survival (OS; 41.0 months vs. OS not reached, P = 0.009) and poorer progression-free survival (28.0 months vs. 73.0 months, P = 0.031). This association was primarily due to patients who received chemoradiation (median OS of high- and low-XRCC1 expression patients, 35.5 months and not reached respectively, HR 3.48; 95% CI: 1.44-8.38; P = 0.006). In patients treated with nonchemoradiation modalities, there was no survival difference by XRCC1 expression. In multivariable analysis, high XRCC1 expression and p16(INK4a)-positive status were independently associated with survival in the overall study population (HR = 2.62; 95% CI: 1.52-4.52; P < 0.001 and HR = 0.21; 95% CI: 0.06-0.71; P = 0.012, respectively) and among chemoradiation patients (HR = 6.02; 95% CI: 2.36-15.37; P < 0.001 and HR = 0.26; 95% CI: 0.08-0.92, respectively; P = 0.037).

CONCLUSIONS

In HNSCC, high XRCC1 protein expression is associated with poorer survival, particularly in patients receiving chemoradiation. Future validation of these findings may enable identification of HNSCC expressing patients who benefit from chemoradiation treatment.

Molecular analysis of DNA repair gene methylation and protein expression during chemical-induced rat lung carcinogenesis

A defective ratio between DNA damage and repair may result in the occurrence of a malignant phenotype. Previous studies have found that many genetic alterations in DNA repair genes occur frequently in lung cancer. However, the epigenetic mechanisms underlying this tumorigenesis are not clear. Herein, we have used a chemical-induced rat lung carcinogenesis model to study the evolution of methylation alterations of DNA repair genes BRCA1, ERCC1, XRCC1, and MLH1. Methylation-specific PCR and immunohistochemistry were used to analyze gene methylation status and protein expression during the progression of lung carcinogenesis. Promoter hypermethylation of BRCA1 was only detected in three samples of infiltrating carcinoma. CpG island hypermethylation of ERCC1, XRCC1, and MLH1 was found to increase gradually throughout lung carcinogenesis progression. Both the prevalence of at least one methylated gene and the average number of methylated genes were heightened in squamous metaplasia and dysplasia compared with normal tissue and hyperplasia, and was further increased in carcinoma in situ (CIS) and infiltrating carcinoma. Immunohistochemical analysis showed that BRCA1 and MLH1 protein expression decreased progressively during the stages of lung carcinogenesis, whereas ERCC1 and XRCC1 expression were only found in later stages. Although methylation levels were elevated for ERCC1 and XRCC1 during carcinogenesis, an inverse correlation with protein expression was found only for BRCA1 and MLH1. These results suggest that a continuous accumulation of DNA repair gene hypermethylation and the consequent protein alterations might be a vital molecular mechanism during the process of multistep chemical-induced rat lung carcinogenesis.