DNA repair gene--XRCC1 in relation to genome instability and role in colorectal carcinogenesis

Survival association of XRCC1 for patients with head and neck squamous cell carcinoma: A systematic review and meta-analysis

Background: Epidemiologic studies have demonstrated that X-ray repair cross-complementary group 1 (XRCC1) is one of the susceptibility factors in head and neck squamous cell carcinoma (HNSCC) patients. However, its clinical prognostic impact remains controversial. Thus, a meta-analysis was performed to clarify the association between XRCC1 and the survival outcomes in HNSCC patients. Methods: Following the Preferred Reporting Items or Systematic Reviews Meta Analyses (PRISMA) 2020 guidelines, literature searches were systematically performed in PubMed, EMBASE, Web of Science, Wanfang, and Chinese National Knowledge Infrastructure (CNKI) databases with manual retrieval. Hazard ratios (HRs) and 95% confidence intervals (CIs) were collected to estimate the correlation between XRCC1 and the survival outcomes of HNSCC patients. Results: Ten studies including 1995 HNSCC patients who satisfied the inclusion and exclusion criteria were included in this meta-analysis. Pooled analysis indicated that XRCC1 Arg399Gln and XRCC1 high protein expression were significantly correlated with poor overall survival with HR of 1.31 (95% CIs: 1.03-1.66, p = 0.027) and 2.32 (95% CIs: 1.55-3.48 p = 0.000) in HNSCC patients. In addition, our results demonstrated that XRCC1 was significantly associated with poor progression-free survival (HR = 1.42, 95% CIs: 1.15-1.75, p = 0.001) in HNSCC patients. ConclusionThis meta-analysis demonstrated that XRCC1 Arg399Gln and XRCC1 high protein expression increase the risk of poor survival for HNSCC patients. XRCC1 is a potential therapeutic target for HNSCC.

Baicalin attenuates XRCC1-mediated DNA repair to enhance the sensitivity of lung cancer cells to cisplatin

Baicalin plays important roles in different types of cancer. A previous report showed that baicalin attenuates cisplatin resistance in lung cancer. However, its mechanism remains unclear. In this study, we investigated the effect and mechanism of baicalin on DNA repair and sensitivity of lung cancer cells to cisplatin. A549 and A549/DPP cells were treated with baicalin and cisplatin. A549/DPP cells were transfected with XRCC1 and siXRCC1. Cell viability and DNA damage were detected by MTT and comet assay. Apoptosis rate and cell cycle were detected by flow cytometry assay. The expressions of Bax, Bcl-2, and Cyclin D1 were detected by western blot. XRCC1 expression was detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot. Baicalin and cisplatin decreased cell viability in A549 and A549/DPP cells in dose-dependent manner. Baicalin enhanced the effect of cisplatin on promoting apoptosis, arresting cell on S stage and triggering DNA damage accompanied with the upregulation of Bcl-2-associated X protein (Bax) and downregulation of B-cell lymphoma 2 (Bcl-2) and Cyclin D1 in A549/DPP cells. Moreover, baicalin promoted the inhibitory effect of cisplatin on XRCC1 expression in A549 and A549/DPP cells. However, the synthetic effects of baicalin and cisplatin on A549/DPP cells were partially inhibited by XRCC1 overexpression and promoted by XRCC1 knockdown. This study demonstrates that baicalin interferes with XRCC1-mediated cellar DNA repair to sensitize lung cancer cells to cisplatin.

Influence of Two DNA Repair Pathway Polymorphisms in Colorectal Cancer Risk in Southwest Iran

Objective:

X-ray cross-complementing group 1 (XRCC1) and 8 Oxo guanine DNA-glycosylase 1 (OGG1) genes are implicated in the repair of single-stranded breaks (SSBRs) and base excision repair (BER) pathways. Common polymorphisms in DNA repair genes are supposed to decrease the capability of DNA repair and cause genetic instability. This study was designed to investigate the association between XRCC1 (rs25487) and OGG1 (rs1052133) polymorphisms and susceptibility to colorectal cancer (CRC) in the Ahvaz city, south-west Iran.

Methods:

This case- control study comprised 150 patients and 150 controls that were selected from 2 educational hospitals in Ahvaz. They were matched for age and gender, and their genotyping was carried out by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

Results:

Our results indicate that the frequency of the Gln (A) allele of XRCC1 (rs25487) is significantly higher in colorectal cancer patients, compare to controls (p = 0.01, OR: 1.54, 95% CI 1.9–13.3). Significant increased risk of cancer was observed in XRCC1 (rs25487) genotypes (p = 0.001 OR: 5.3, 95% CI 1.9–14.2 for Gln / Gln), while no association was found between OGG1 (rs1052133) and colorectal cancer risk (p = 0.6).

Conclusion:

Our study suggests that XRCC1 (rs25487) polymorphism might be associated with an increasing risk of CRC in Ahvaz. It also demonstrates positive correlation between the XRCC1 (rs25487) genotypes and demographic characteristics, such as smoking and increased age in patients and control groups.

DNA repair genes in astrocytoma tumorigenesis, progression and therapy resistance

Glioblastoma (GBM) is the most common and malignant type of primary brain tumor, showing rapid development and resistance to therapies. On average, patients survive 14.6 months after diagnosis and less than 5% survive five years or more. Several pieces of evidence have suggested that the DNA damage signaling and repair activities are directly correlated with GBM phenotype and exhibit opposite functions in cancer establishment and progression. The functions of these pathways appear to present a dual role in tumorigenesis and cancer progression. Activation and/or overexpression of ATRX, ATM and RAD51 genes were extensively characterized as barriers for GBM initiation, but paradoxically the exacerbated activity of these genes was further associated with cancer progression to more aggressive stages. Excessive amounts of other DNA repair proteins, namely HJURP, EXO1, NEIL3, BRCA2, and BRIP, have also been connected to proliferative competence, resistance and poor prognosis. This scenario suggests that these networks help tumor cells to manage replicative stress and treatment-induced damage, diminishing genome instability and conferring therapy resistance. Finally, in this review we address promising new drugs and therapeutic approaches with potential to improve patient survival. However, despite all technological advances, the prognosis is still dismal and further research is needed to dissect such complex mechanisms.

Hyperglycemia Associated Metabolic and Molecular Alterations in Cancer Risk, Progression, Treatment, and Mortality

Cancer and diabetes are amongst the leading causes of deaths worldwide. There is an alarming rise in cancer incidences and mortality, with approximately 18.1 million new cases and 9.6 million deaths in 2018. A major contributory but neglected factor for risk of neoplastic transformation is hyperglycemia. Epidemiologically too, lifestyle patterns resulting in high blood glucose level, with or without the role of insulin, are more often correlated with cancer risk, progression, and mortality. The two conditions recurrently exist in comorbidity, and their interplay has rendered treatment regimens more challenging by restricting the choice of drugs, affecting surgical consequences, and having associated fatal complications. Limited comprehensive literature is available on their correlation, and a lack of clarity in understanding in such comorbid conditions contributes to higher mortality rates. Hence, a critical analysis of the elements responsible for enhanced mortality due to hyperglycemia-cancer concomitance is warranted. Given the lifestyle changes in the human population, increasing metabolic disorders, and glucose addiction of cancer cells, hyperglycemia related complications in cancer underline the necessity for further in-depth investigations. This review, therefore, attempts to shed light upon hyperglycemia associated factors in the risk, progression, mortality, and treatment of cancer to highlight important mechanisms and potential therapeutic targets.

Genetic variants of XRCC1 and risk of hepatocellular carcinoma in chronic hepatitis C patients

BACKGROUND

Hepatitis C virus (HCV) related liver cirrhosis occurs in about 20% of chronically infected patients over a duration of 10-20 years, and within 5 years approximately 10-20% of these cirrhotic patients will develop hepatocellular carcinoma (HCC). Previous studies report that the X-ray repair cross-complementing group1 gene (XRCC1) is important in the risk of HCC development; however, results obtained from these studies are conflicting rather than conclusive. We hypothesised an association between single nucleotide polymorphisms (SNPs) in XRCC1 with the HCC risk on a background of chronic hepatitis C.

MATERIALS AND METHODS

We recruited 210 subjects, 70 with HCC, 70 with cirrhosis and 70 healthy controls. Two SNPs [c.1254C>T(rs2293035) and c.1517G>C(rs139599857)] in XRCC1 were genotyped using created restriction site-polymerase chain reaction (CRS-PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP) methods.

RESULTS

The TT genotype, CT genotype and T-allele in c.1254C>T (rs2293035) were linked to risk of HCC compared to the CC genotype: OR 3.58 [confidence interval (CI) 95%: 1.19-10.7] p = 0.019; OR 2.16 (CI 95%: 1.04-4.47) p = 0.037 and OR 2.10 (CI 95%: 1.2-3.3) p = 0.006, respectively. Regarding c.1517G>C (rs139599857), the CC genotype, GC genotype and C-allele were linked with higher risk of developing HCC compared to GG genotype: OR 4.77 (CI 95%: 1.3-16.9), p = 0.016; OR 3.02 (CI 95%: 1.46-6.2), p = 0.002 and OR 2.4 (CI 95%: 1.4-4.0), p = 0.001, respectively.

CONCLUSION

We conclude that the T-allele of c.1254C>T (rs2293035) and the C allele of c.1517G>C (rs139599857) genetic variants may be associated with increased HCC risk among chronic hepatitis C patients.

The contribution of XRCC3 genotypes to childhood acute lymphoblastic leukemia

Purpose

A growing body of evidence shows an association between DNA repair protein genotypes and susceptibility to various cancers. However, few studies have assessed the contribution of the genotype of XRCC3, a homologous repair gene, to the occurrence or prognosis of childhood acute lymphoblastic leukemia (ALL). In this study, we investigated the contribution of seven XRCC3 polymorphisms to childhood ALL.

Patients and methods

We recruited 266 patients with childhood ALL and 266 healthy controls. Genomic DNA was isolated from peripheral blood samples. The XRCC3 rs1799794, rs45603942, rs1799796, rs861530, rs28903081, rs861539, and rs3212057 polymorphic genotypes of each subject were determined through conventional polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis.

Results

Genotypes with the rs861539 polymorphism were significantly associated with the risk of childhood ALL. The allelic distribution analyses suggested a significant association between the T allele at rs861539 with an increased risk of childhood ALL in the Taiwanese population. Polymorphic variants of XRCC3 at rs3212057 or rs28903081 did not exist in the study population. XRCC3 rs1799794, rs45603942, rs1799796, and rs861530 were not significantly associated with the risk of childhood ALL in the Taiwanese population.

Conclusion

Our findings suggest that XRCC3 genotypes with polymorphisms at rs861539 may play a role in determining individual susceptibility to childhood ALL in this Taiwanese population. The polymorphism may be a potential detector and predictor of childhood ALL.

Autologous hematopoietic stem cell transplantation in lymphoma patients is associated with a decrease in the double strand break repair capacity of peripheral blood lymphocytes

Patients who undergo autologous hematopoietic stem cell transplantation (aHCT) for treatment of a relapsed or refractory lymphoma are at risk of developing therapy related- myelodysplasia/acute myeloid leukemia (t-MDS/AML). Part of the risk likely resides in inherent interindividual differences in their DNA repair capacity (DRC), which is thought to influence the effect chemotherapeutic treatments have on the patient's stem cells prior to aHCT. Measuring DRC involves identifying small differences in repair proficiency among individuals. Initially, we investigated the cell model in healthy individuals (primary lymphocytes and/or lymphoblastoid cell lines) that would be appropriate to measure genetically determined DRC using host-cell reactivation assays. We present evidence that interindividual differences in DRC double-strand break repair (by non-homologous end-joining [NHEJ] or single-strand annealing [SSA]) are better preserved in non-induced primary lymphocytes. In contrast, lymphocytes induced to proliferate are required to assay base excision (BER) or nucleotide excision repair (NER). We established that both NHEJ and SSA DRCs in lymphocytes of healthy individuals were inversely correlated with the age of the donor, indicating that DSB repair in lymphocytes is likely not a constant feature but rather something that decreases with age (~0.37% NHEJ DRC/year). To investigate the predictive value of pre-aHCT DRC on outcome in patients, we then applied the optimized assays to the analysis of primary lymphocytes from lymphoma patients and found that individuals who later developed t-MDS/AML (cases) were indistinguishable in their DRC from controls who never developed t-MDS/AML. However, when DRC was investigated shortly after aHCT in the same individuals (21.6 months later on average), aHCT patients (both cases and controls) showed a significant decrease in DSB repair measurements. The average decrease of 6.9% in NHEJ DRC observed among aHCT patients was much higher than the 0.65% predicted for such a short time frame, based on ageing results for healthy individuals.

Gene polymorphism in DNA repair genes XRCC1 and XRCC6 and association with colorectal cancer in Swedish patients

The DNA repair genes XRCC1 and XRCC6 have been proposed to participate in the pathological process of cancer by modulating the DNA repair capacity. This study evaluated the susceptibility of the single-nucleotide polymorphisms (SNPs) XRCC1 (rs25487, G > A) and XRCC6 (rs2267437, C > G) to colorectal cancer (CRC) and their association with clinical parameters in Swedish patients with CRC. Using the TaqMan system, these SNPs were screened in 452 patients and 464 controls. No significant difference in genotype distribution was found between the patients and controls, or any significant association with cancer-specific or disease-free survival in patients. However, we showed that the carriers of allele A in XRCC1 (rs25487, G > A) were connected with a higher risk of disseminated CRC (Odds Ratio = 1.64; 95% Confidence Interval = 1.12-2.41, p = 0.012).

XRCC1 R399Q polymorphism and colorectal cancer risk in the Chinese Han population: a meta-analysis

X-ray repair cross-complementing group 1 (XRCC1) plays a key role in DNA repair, genetic instability, and tumorigenesis. The XRCC1 R399Q polymorphism has been reported in some studies to influence the risk of colorectal cancer (CRC), though this remains controversial. We performed a meta-analysis to determine the association of XRCC1 R399Q polymorphisms with CRC risk in the Chinese Han population. A literature search was conducted using PubMed, EMBASE, and the China National Knowledge Infrastructure to identify eligible studies published before June 2014. The pooled odds ratio (OR) and corresponding 95% confidence interval (CI) were used to estimate the effect of XRCC1 R399Q polymorphisms on CRC risk. Eleven case-control studies with a total of 3194 CRC cases and 4472 controls were identified. No significant association between the XRCC1 R399Q polymorphism and CRC risk was observed in the Chinese Han population (Gln/Gln vs. Arg/Arg, OR = 1.26, 95% CI = 0.85-1.87, P OR = 0.242; Arg/Gln vs. Arg/Arg, OR = 0.95, 95% CI = 0.70-1.18, P OR = 0.651; dominant model, OR = 1.09, 95% CI = 0.86-1.38, P OR = 0.480; and recessive model, OR = 1.24, 95% CI = 0.91-1.70, P OR = 0.177). After excluding two studies that deviated from the Hardy-Weinberg equilibrium, there remained no significant association between XRCC1 R399Q and CRC risk. No publication bias was found using the funnel plot and Egger's test. Our meta-analysis results suggest that the XRCC1 R399Q polymorphism is not associated with increased risk of CRC in the Chinese Han population.