Search Results (114)

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system characterized by demyelination and neurodegeneration. While its etiology remains unclear, both genetic and environmental factors, including oxidative stress, have been implicated in the development of the disease. The base excision repair (BER) pathway plays a critical role in repairing oxidative DNA damage. This study investigated the association between polymorphisms in BER-related genes and MS susceptibility in a Central European population. Ten SNPs across seven BER genes were genotyped in 102 patients with MS and 118 healthy controls. Six SNPs were significantly associated with MS. Increased risk was observed for rs25478 in XRCC1 (OR = 2.37, 95% CI: 1.44–3.91, p < 0.0001), rs3087404 in SMUG1 (OR = 2.80, 95% CI: 1.49–5.26, p = 0.0012), and rs3219493 in MUTYH (OR = 2.23, 95% CI: 1.35–3.67, p = 0.0018). Conversely, reduced risk was associated with rs2307293 in MBD4 (OR = 0.42, 95% CI: 0.23–0.78, p = 0.006), rs3219489 in MUTYH (OR = 0.55, 95% CI: 0.31–0.97, p = 0.038), and rs4135054 in TDG (OR = 0.52, 95% CI: 0.29–0.94, p = 0.031). Haplotype analysis was performed for SNPs in strong linkage disequilibrium. Only rs3219489 and rs3219472 within the MUTYH gene showed strong LD (r² = 0.90), justifying haplotype-based analysis. Among four inferred haplotypes, the rare G–C haplotype was significantly associated with reduced MS risk (Score = −2.10, p = 0.035), suggesting a protective effect of this allele combination. Other SNPs not in LD were analyzed using a multivariable logistic regression model. Significant associations with decreased MS risk were found for rs1052133 in OGG1 (OR = 0.57, p = 0.043), rs2307293 in MBD4 (OR = 0.16, p = 0.010), and rs4135054 in TDG (OR = 0.38, p < 0.001), while rs3087404 in SMUG1 increased MS risk (OR = 1.98, p = 0.013). These results suggest that genetic variation in BER genes, including both single SNP effects and haplotypes, contributes to MS susceptibility. Further studies are warranted to explore the functional consequences of these variants and validate findings in larger, independent cohorts. Full article

In recent years, an increasingly important role in the etiopathogenesis of lung cancer has been attributed to genetic predisposition. Current genetic research suggests that the increased risk of this cancer may be due to gene polymorphism within repair genes. In the case of lung cancer, observations about genes involved in the DNA repair system by cutting bases of nitrogen—base excision repair (BER)—seem to be interesting. Most attention has been devoted to the XRCC1 gene, which coordinates the various stages of BER. The aim of this study was to assess the role of the single nucleotide polymorphism Arg399Gln in the XRCC1 gene as a factor influencing the risk of lung cancer. The study involved 118 patients with non-small cell lung cancer (NSCLC). The control group consisted of 60 people who did not have cancer. The study proved that the polymorphism of the XRCC1 gene is characterized by a statistically significant relationship with the onset of cancer. There were no statistically significant differences between the Arg399Gln polymorphism of the XRCC1 gene and risk factors for non-small cell lung cancer, such as age, sex, smoking and its duration, or place of residence, as well as between the histological type of the tumor or its severity. Detailed analysis of three genotypes—Arg/Arg, Arg/Gln, and Gln/Gln—showed that the incidence of particular genotypes in the group of patients was, respectively, 16.10%, 27.12%, and 58.78%. In the case of the Gln/Gln genotype, the most common associated histopathological type was squamous cell carcinoma, and in the case of adenocarcinoma, the most common genotype was Arg/Arg. It was estimated that each Arg allele reduced the chance of tumor occurrence to 0.48 times the reference value, i.e., the Gln/Gln genotype class for the Arg/Gln genotype and the Arg/Gln genotype for the Arg/Arg genotype. The relationship between the male sex and the occurrence of cancer remained insignificant, in contrast to the presence of nicotinism. Studies suggest that the Arg399Gln polymorphism of the XRCC1 gene has limited prognostic significance in non-small cell lung cancer. Full article

Background: The MiBlend Study investigated the effect of consuming different combinations of fruits and vegetables (F&Vs) blends on markers of chronic disease risk and gene expression changes in healthy human subjects. Overall, the increase in F&Vs led to reduced susceptibility to the induction of DNA damage ex vivo, higher antioxidant capacity of plasma, and improved microvasculature as reflected by retinal analysis. As with most dietary intervention studies, inter-individual variability was observed in the responses, which might be the consequence of genetic differences. Therefore, this study aims to identify if genetic variants in relevant genes affect outcomes and responses to the dietary interventions. Methods: The literature review identified 15 polymorphic genes related to phytochemical metabolism, oxidative stress, and detoxification, which were tested in 146 participant samples using TaqMan and PCR analysis. The effect of genotypes on study outcomes was determined via analysis of variance. Results: XRCC1 wildtype carriers were more protected from ex vivo-induced DNA damage after consuming flavanol-rich F&Vs than other variants. XRCC1 is involved in DNA repair, particularly oxidative damage, and its wildtype allele enhances repair efficiency. GSTP1 wildtype carriers had a larger improvement in microvasculature after all F&V blends, especially those rich in polyphenols. GSTP1 polymorphisms likely affect microvascular responses to polyphenol-rich F&V intake by modulating detoxification and fiber-derived butyrate that can influence arterial dilation and endothelial function. Conclusions: Stratifying participants by relevant genetic polymorphisms can reveal predisposed responses to nutrients and guide efforts to personalize disease prevention strategies. Full article

The Base Excision Repair (BER) pathway involves a highly coordinated series of protein–protein interactions that facilitate the recognition, excision, and repair of damaged bases. Key enzymes such as DNA glycosylases, apurinic/apyrimidinic endonuclease 1 (APE1), polynucleotide kinase-phosphatase (PNKP), DNA polymerase b (Pol β), ligase IIIα (LigIIIα), poly (ADP-ribose) polymerases PARP1 and PARP2, and X-ray repair cross-complementing protein 1 (XRCC1) catalyze BER in a tightly regulated molecular network. These interactions ensure the seamless handoff of DNA intermediates between the core enzymes of the BER pathway. Understanding the details of protein–protein interactions in BER provides valuable insights into the molecular underpinnings of DNA repair processes. In this review, we focus on protein–protein interactions between the components of the single-nucleotide BER (SN-BER) pathway and other proteins that interact with BER components and regulate the coordination of the pathway. We also briefly discuss the interactions of other proteins that interact with the components of SN-BER based on functional evidence. Full article

Background/Objectives: Radiotherapy is a cornerstone in the treatment of breast cancer, yet its use is frequently accompanied by skin toxicities that vary in severity and timing among patients. The objective of this meta-analysis is to systematically evaluate the pooled impact of genetic variations on the risk and severity of acute and late skin side effects from radiotherapy in breast cancer patients. Materials and Methods: A systematic literature search was conducted across PubMed, Embase, and Scopus to identify studies published between 2014 and 2024 that examined associations between genetic polymorphisms and radiotherapy-induced skin toxicity. Studies were selected based on predefined inclusion and exclusion criteria, and data were synthesized using a random-effects meta-analysis model. The risk of bias was evaluated using the ROBINS-I tool, and publication bias was assessed through funnel plots and Egger’s test. Results: A total of 11 studies involving breast cancer patients were included, identifying associations between various gene polymorphisms and skin toxicity. The pooled analysis revealed that patients with specific genetic variants had a 53% increased risk of acute skin side effects and a 44% increased risk of late effects. Notable implicated genes included XRCC2, IFNG, ATM, TGFB1, and PER3. Significant heterogeneity and publication bias were noted across studies, warranting cautious interpretation. Conclusions: This meta-analysis highlights the role of genetic variation in predicting radiotherapy-induced skin toxicity in breast cancer patients. These findings support the future development of predictive biomarkers and personalized radiotherapy strategies to minimize treatment-related toxicity. Full article

Introduction: This study investigates the distribution and interaction of three polymorphisms—XRCC1 (rs1799782), CHEK2 (rs17879961), and XPD (rs238406)—in Romanian breast cancer patients, aiming to understand their association with histopathological subtypes, age, and BMI. Materials and Methods: This retrospective study analyzed 36 breast cancer patients from a Romanian clinic (2020–2024) with complete genetic data for XRCC1 (rs1799782), CHEK2 (rs17879961), and XPD (rs238406). The patients had invasive, non-metastatic breast cancer and no history of other cancers. Statistical analysis with Jamovi included descriptive stats, McNemar’s test for genotype associations, and multinomial logistic regression to explore links between variants, age, BMI, and tumor subtypes. Results: McNemar tests showed no significant association between XRCC1 and CHEK2 (p = 0.180), nor between XRCC1 and XPD (p = 0.03) or XPD and CHEK2 (p = 0.049) after applying the Bonferroni correction (α = 0.0167), indicating no statistically significant genetic dependency among these variants. A multinomial logistic regression model found that genetic variants, BMI, and age significantly predicted breast cancer subtypes, particularly CDI TNB. All predictors remained significant in the comparisons of CDI TNB vs. CDI LB/CDI LA. Notably, these associations remained unchanged even after applying the Bonferroni correction (α = 0.0021), confirming the robustness of the findings. Conclusions: This study identifies significant associations between XRCC1, CHEK2, and XPD gene variants and CDI TNB, suggesting a role of DNA repair deficiencies in its pathogenesis. Protective genotypes were under-represented in TNB cases. Limited links with luminal subtypes highlight TNB’s distinct genetic profile. Results support further research on these polymorphisms as markers for TNB risk and precision treatment. Full article

Biogas plants for sewage and organic waste treatment are rapidly expanding. While these facilities provide valuable benefits, such as renewable energy production and the promotion of circular economy practices, they also emit airborne particles of biological origin, which may pose potential health risks. This study aims to evaluate, by in vitro assay, the cytotoxic and genotoxic potential of PM₁₀ sub-fractions (0.49–10 µm and <0.49 µm) generated in eight different plants, also assessing the endotoxin component using the Limulus Amebocyte Lysate (LAL) assay. Human embryonic lung fibroblasts (HELF) were exposed to organic extracts of particulate matter (PM). Cytotoxic effects (XTT assay) were analyzed, along with the modulation of gene expression involved in DNA repair (ERCC1, XRCC1, XPA, and XPF) and IL-8 production as a marker of inflammatory response. PM₁₀ and endotoxin concentrations varied significantly among the plants (ANOVA, p < 0.01), with PM₁₀ levels ranging from 14 to 18,000 µg/m³ and endotoxin content from 1 to 138 EU/m³. Exposure significantly increased ERCC1 and IL-8 expression by 25% and 53%, respectively (paired t-test, p < 0.01). IL-8 expression correlated with endotoxin exposure (Spearman’s rho = 0.35; p < 0.01). A deeper understanding of the biological component of airborne PM₁₀ can enhance risk assessments for occupational and nearby resident communities’ safety. Full article

Meiotic recombination is initiated by the formation of programmed DNA double-strand breaks during spermatogenesis. PRDM9 determines the localization of recombination hotspots by interacting with several protein complexes in mammals. The function of PRDM9 is not well understood during spermatogenesis in mice or yaks. In this study, we applied yeast two-hybrid assays combined with next-generation sequencing techniques to screen the complete set of PRDM9-interacting proteins and explore its novel functions in yak spermatogenesis. Our results showed that 267 PRDM9-interacting proteins were identified. The gene ontology (GO) analysis of the interacting proteins revealed that the GO terms were primarily associated with spermatogenesis, positive regulation of double-strand break repair via homologous recombination, RNA splicing, the ubiquitin-dependent ERAD pathway, and other biological processes. MKX and PDCD5 were verified to be strongly interacting with PRDM9 and expressed in prophase I of meiosis in both mouse and yak testes. The localizations of RNA splicing genes including THOC5, DDX5, and XRCC6 were expressed in spermatocytes. Cattleyak is the hybrid offspring of a yak and a domestic cow, and the male offspring are sterile. The gene expression of the interacting proteins was also examined in the sterile male hybrid of yak and cattle. Among the 58 detected genes, 55 were downregulated in cattleyak. In conclusion, we established a complete PRDM9 interaction network, and a novel function of PRDM9 was identified, which will further promote our understanding of spermatogenesis. It also provides new insights for the study of hybrid male sterility. Full article

Lung cancer remains the leading cause of cancer-related mortality globally, with a poor prognosis primarily due to late diagnosis and limited treatment options. This research highlights the critical demand for advanced prognostic tools by creating a model centered on aging-related genes (ARGs) to improve prediction and treatment strategies for lung adenocarcinoma (LUAD). By leveraging datasets from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO), we developed a prognostic model that integrates 14 ARGs using the least absolute shrinkage and selection operator (LASSO) alongside Cox regression analyses. The model exhibited strong predictive performance, achieving area under the curve (AUC) values greater than 0.8 for one-year survival in both internal and external validation cohorts. The risk scores generated by our model were significantly correlated with critical features of the tumor microenvironment, including the presence of cancer-associated fibroblasts (CAFs) and markers of immune evasion, such as T-cell dysfunction and exclusion. Higher risk scores correlated with a more tumor-promoting microenvironment and increased immune suppression, highlighting the model’s relevance in understanding LUAD progression. Additionally, XRCC6, a protein involved in DNA repair and cellular senescence, was found to be upregulated in LUAD. Functional assays demonstrated that the knockdown of XRCC6 led to decreased cell proliferation, whereas its overexpression alleviated DNA damage, highlighting its significance in tumor biology and its potential therapeutic applications. This study provides a novel ARG-based prognostic model for LUAD, offering valuable insights into tumor dynamics and the tumor microenvironment, which may guide the development of targeted therapies and improve patient outcomes. Full article

Assessments of breast cancer (BC) risk in carriers of pathogenic variants identified by gene panel testing in different populations are highly in demand worldwide. We performed target sequencing of 78 genes involved in DNA repair in 860 females with BC and 520 age- and family history-matched controls from Central Russia. Among BC patients, 562/860 (65.3%) were aged 50 years or less at the time of diagnosis. In total, 190/860 (22%) BC patients were carriers of 198 pathogenic/likely pathogenic (P/LP) variants in 30 genes, while among controls, 32/520 (6.2%) carriers of P/LP variants in 17 genes were identified. The odds ratio [95% confidence interval] was 16.3 [4.0–66.7] for BRCA1; 12.0 [2.9–45.9] for BRCA2; and 7.3 [0.9–56.7] for ATM (p < 0.05). Previously undescribed BRCA1/2, ATM, and PALB2 variants, as well as novel recurrent mutations, were identified. The contribution to BC susceptibility of truncating variants in the genes BARD1, RAD50, RAD51C, NBEAL1 (p. E1155*), and XRCC2 (p. P32fs) was evaluated. The BLM, NBN, and MUTYH genes did not demonstrate associations with BC risk. Finding deleterious mutations in BC patients is important for diagnosis and management; in controls, it opens up the possibility of prevention and early diagnostics. Full article

Serrated polyposis syndrome (SPS) is characterized by the development of multiple colorectal serrated polyps and increased predisposition to colorectal cancer (CRC). However, the molecular basis of SPS, especially in cases presenting family history of SPS and/or polyps and/or CRC in first-degree relatives (SPS-FHP/CRC), is still poorly understood. In a previous study, we proposed the existence of two molecular entities amongst SPS-FHP/CRC families, proximal/whole-colon and distal SPS-FHP/CRC, according to the preferential location of lesions and somatic events involved in tumor initiation. In the present study, we aimed to investigate these distinct subgroups of SPS patients in a larger cohort at the germline level and to identify the genetic defects underlying an inherited susceptibility for these two entities. Next-generation sequencing was performed using multigene analysis with a custom-designed panel in a Miseq platform in 60 SPS patients (with and without/unknown FHP/CRC). We found germline pathogenic variants in 6/60 patients (ATM, FANCM, MITF, RAD50, RAD51C, and RNF43). We also found variants of unknown significance (VUS), with prediction of probable damaging effect in 23/60 patients (ATM, BLM, BRCA1, FAN1, ERCC2, ERCC3, FANCA, FANCD2, FANCL, MSH2, MSH6, NTHL1, PALB2, PDGFRA, PMS2, PTCH1, RAD51C, RAD51D, RECQL4, TSC2, WRN, and XRCC5 genes). Most variants were detected in gene coding for proteins of the Fanconi Anemia (FA) pathway involved in the DNA Interstrand-Cross Link repair (ICLR). Notably, variants in ICLR genes were significantly more frequent in the proximal/whole-colon than in the distal subgroup [15/44 (34%) vs 1/16 (6%), p = 0.025], as opposed to the non-ICLR genes that were slightly more frequent in the distal group [8/44 (18%) vs. 5/16 (31%), p > 0.05]. Germline defects in the DNA-ICLR genes may contribute to increased serrated colorectal polyps/carcinoma risk in SPS patients, particularly in proximal/whole-colon SPS. The inclusion of DNA-ICLR genes in the genetic diagnosis of SPS patients, mainly in those with proximal/whole-colon lesions, should be considered and validated by other studies. In addition, patients with germline defects in the DNA-ICLR genes may be more sensitive to treatment with platinum-based therapeutics, which can have implications in the clinical management of these patients. Full article

Targeting DNA repair pathways is an important strategy in anticancer therapy. However, the unrevealed interactions between different DNA repair systems may interfere with the desired therapeutic effect. Among DNA repair systems, BER and NHEJ protect genome integrity through the entire cell cycle. BER is involved in the repair of DNA base lesions and DNA single-strand breaks (SSBs), while NHEJ is responsible for the repair of DNA double-strand breaks (DSBs). Previously, we showed that BER deficiency leads to downregulation of NHEJ gene expression. Here, we studied BER’s response to NHEJ deficiency induced by knockdown of NHEJ scaffold protein XRCC4 and compared the knockdown effects in normal (TIG-1) and hTERT-modified cells (NBE1). We investigated the expression of the XRCC1, LIG3, and APE1 genes of BER and LIG4; the Ku70/Ku80 genes of NHEJ at the mRNA and protein levels; as well as p53, Sp1 and PARP1. We found that, in both cell lines, XRCC4 knockdown leads to a decrease in the mRNA levels of both BER and NHEJ genes, though the effect on protein level is not uniform. XRCC4 knockdown caused an increase in p53 and Sp1 proteins, but caused G1/S delay only in normal cells. Despite the increased p53 protein, p21 did not significantly increase in NBE1 cells with overexpressed hTERT, and this correlated with the absence of G1/S delay in these cells. The data highlight the regulatory function of the XRCC4 scaffold protein and imply its connection to a transcriptional regulatory network or mRNA metabolism. Full article

Background: High variability in the age at cancer diagnosis in Lynch syndrome (LS) patients is widely observed, even among relatives with the same germline pathogenic variant (PV) in the mismatch repair (MMR) genes. Genetic polymorphisms and lifestyle factors are thought to contribute to this variability. We investigated the influence of previously reported genetic polymorphisms on the age at cancer diagnosis in a homogenous LS cohort with a South African founder germline PV c.1528C>T in the MLH1 gene. Methods: A total of 359 LS variant heterozygotes (LSVH) from 60 different families were genotyped for specific genetic polymorphisms in GSTM1, GSTT1, CYP1A1, CYP17, PPP2R2B, KIF20A, TGFB1, XRCC5, TNF, BCL2, CHFR, CDC25C, ATM, TTC28, CDC25C, HFE, and hTERT genes using Multiplex Polymerase Chain Reaction and MassArray methods. Kaplan–Meier survival analysis, univariate and multivariate Cox proportional hazards gamma shared frailty models adjusted for sex were used to estimate the association between age at cancer diagnosis and polymorphism genotypes. A p-value < 0.05 after correcting for multiple testing using the Benjamini–Hochberg method was considered significant at a 95% confidence interval. Results: We identified three genotypes in the cell-cycle regulation, DNA repair, and xenobiotic-metabolism genes significantly associated with age at cancer diagnosis in this cohort. The CYP1A1 rs4646903 risk (GG) and CDC25C rs3734166 polymorphic (GA+AA) genotypes were significantly associated with an increased risk of a younger age at cancer diagnosis (Adj HR: 2.03 [1.01–4.08], p = 0.034 and Adj HR: 1.53 [1.09–2.14], p = 0.015, respectively). LSVH who were heterozygous for the XRCC5 rs1051685 SNP showed significant protection against younger age at cancer diagnosis (Adj HR: 0.69 [CI, 0.48–0.99], p = 0.043). The risk of a younger age at any cancer diagnosis was significantly high in LS carriers of one to two risk genotypes (Adj HR: 1.49 [CI: 1.06–2.09], corrected p = 0.030), while having one to two protective genotypes significantly reduced the risk of developing any cancer and CRC at a younger age (Adj HR: 0.52 [CI: 0.37–0.73], and Adj HR: 0.51 [CI: 0.36–0.74], both corrected p < 0.001). Conclusions: Polymorphism genotypes in the cell-cycle regulation, DNA repair, and xenobiotic metabolizing genes may influence the age at cancer diagnosis in a homogenous LS cohort with a South African founder germline PV c.1528C>T in the MLH1 gene. Full article

Standard first-line chemotherapy in small cell lung cancer (SCLC) is based on the platinum plus etoposide combination. Despite a high objective response rate, responses are not durable and chemotherapy-induced toxicity may compromise treatment. Genetic variants in genes involved in the DNA-repair pathways and in etoposide metabolization could predict treatment efficacy and safety and help personalize platinum-based chemotherapy. Germline polymorphisms in XRCC1, ERCC1, ERCC2, ABCB1, ABCC3, UGT1A1 and GSTP1 genes were investigated in 145 patients with SCLC. The tumor expression of ERCC1 was determined using immunohistochemistry, and the tumor expression of ERCC1-XPF was determined via a proximity ligation assay. Survival analyses showed a statistically significant association between the ERCC1 rs11615 variant and median progression-free survival (PFS) in patients with limited-stage (LS) SCLC (multivariate: hazard ratio 3.25, [95% CI 1.38–7.70]; p = 0.007). Furthermore, we observed differences between the ERCC1-XPF complex and median PFS in LS-SCLC, although statistical significance was not reached (univariate: positive expression 10.8 [95% CI 4.09–17.55] months versus negative expression 13.3 [95% CI 7.32–19.31] months; p = 0.06). Safety analyses showed that the ERCC2 rs1799793 variant was significantly associated with the risk of grade ≥ 3 thrombocytopenia in the total cohort (multivariate: odds ratio 3.15, [95% CI 1.08–9.17]; p = 0.04). Our results provide evidence that ERCC1 and ERCC2 variants may predict the efficacy and safety of platinum-based chemotherapy in SCLC patients. LS-SCLC patients may benefit most from ERCC1 determination, but prospective studies are needed. Full article

Non-membrane compartments or biomolecular condensates play an important role in the regulation of cellular processes including DNA repair. Here, an ability of XRCC1, a scaffold protein involved in DNA base excision repair (BER) and single-strand break repair, to form protein-rich microphases in the presence of DNA duplexes was discovered. We also showed that the gap-filling activity of BER-related DNA polymerase λ (Pol λ) is significantly increased by the presence of XRCC1. The stimulation of the Pol λ activity was observed only at micromolar XRCC1 concentrations, which were well above the nanomolar dissociation constant determined for the XRCC1–Pol λ complex and pointed to the presence of an auxiliary stimulatory factor in addition to protein–protein interactions. Indeed, according to dynamic light scattering measurements, the stimulation of the Pol λ activity by XRCC1 was coupled with microphase separation in a protein–DNA mixture. Fluorescence microscopy revealed colocalization of Pol λ, XRCC1, and gapped DNA within the microphases. Thus, stimulation of Pol λ activity is caused both by its interaction with XRCC1 and by specific conditions of microphase separation; this phenomenon is shown for the first time. Full article