MicroRNA profile and iron-related gene expression in hepatitis C-related hepatocellular carcinoma: a preliminary study.

INTRODUCTION: Hepatocellular carcinoma (HCC) is very difficult to diagnose, especially in its early stages. Non-invasive diagnostic and prognostic factors for this cancer are urgently needed. The purpose of our study was to investigate whether the microRNAs (miRNAs) regulating genes involved in iron homeostasis, whose disruption is a hallmark of HCC, offer potential as diagnostic or prognostic factors of HCV-related hepatocellular carcinoma. MATERIAL AND METHODS: Serum and tumor samples, and adjacent liver specimens, were obtained from 65 HCC patients. Additionally, serum samples were obtained from 65 healthy controls. In total, 28 circulating and eight tissue microRNA expression profiles were estimated by TaqMan qPCR. RESULTS: The expression profiles of all tested miRNAs were altered in the hepatocellular carcinoma patients. Iron level was negatively related to serum miR-96 level in healthy controls. Although the expression of iron metabolism proteins correlated with the level of serum miRNA in the controls, this was not observed in cancer patients. In the group of cancer patients, Let-7a, miR-29b, and miR-133a were positively related to ferroportin, transferrin and ferritin levels, while miR-31, miR-221 and miR-532 were negatively related to ferroportin, transferrin receptor 1 and ferritin levels. According to ROC curve analyses, 15 miRNAs are able to discriminate with 100% sensitivity and specificity between hepatocellular carcinoma patients and healthy subjects, which is more efficient than α-fetoprotein. CONCLUSIONS: Circulating miRNAs that regulate the expression of iron metabolism proteins should be evaluated as promising candidates for HCV-related HCC diagnostic agents.

Molecular Aspects of Senescence and Organismal Ageing-DNA Damage Response, Telomeres, Inflammation and Chromatin.

Cells can become senescent in response to stress. Senescence is a process characterised by a stable proliferative arrest. Sometimes it can be beneficial-for example, it can suppress tumour development or take part in tissue repair. On the other hand, studies show that it is also involved in the ageing process. DNA damage response (DDR) is triggered by DNA damage or telomere shortening during cell division. When left unresolved, it may lead to the activation of senescence. Senescent cells secrete certain proteins in larger quantities. This phenomenon is referred to as senescence-associated secretory phenotype (SASP). SASP can induce senescence in other cells; evidence suggests that overabundance of senescent cells contributes to ageing. SASP proteins include proinflammatory cytokines and metalloproteinases, which degrade the extracellular matrix. Shortening of telomeres is another feature associated with organismal ageing. Older organisms have shorter telomeres. Restoring telomerase activity in mice not only slowed but also partially reversed the symptoms of ageing. Changes in chromatin structure during senescence include heterochromatin formation or decondensation and loss of H1 histones. During organismal ageing, cells can experience heterochromatin loss, DNA demethylation and global histone loss. Cellular and organismal ageing are both complex processes with many aspects that are often related. The purpose of this review is to bring some of these aspects forward and provide details regarding them.

Regulation of DNA Damage Response and Homologous Recombination Repair by microRNA in Human Cells Exposed to Ionizing Radiation.

Ionizing radiation may be of both artificial and natural origin and causes cellular damage in living organisms. Radioactive isotopes have been used significantly in cancer therapy for many years. The formation of DNA double-strand breaks (DSBs) is the most dangerous effect of ionizing radiation on the cellular level. After irradiation, cells activate a DNA damage response, the molecular path that determines the fate of the cell. As an important element of this, homologous recombination repair is a crucial pathway for the error-free repair of DNA lesions. All components of DNA damage response are regulated by specific microRNAs. MicroRNAs are single-stranded short noncoding RNAs of 20-25 nt in length. They are directly involved in the regulation of gene expression by repressing translation or by cleaving target mRNA. In the present review, we analyze the biological mechanisms by which miRNAs regulate cell response to ionizing radiation-induced double-stranded breaks with an emphasis on DNA repair by homologous recombination, and its main component, the RAD51 recombinase. On the other hand, we discuss the ability of DNA damage response proteins to launch particular miRNA expression and modulate the course of this process. A full understanding of cell response processes to radiation-induced DNA damage will allow us to develop new and more effective methods of ionizing radiation therapy for cancers, and may help to develop methods for preventing the harmful effects of ionizing radiation on healthy organisms.

Elevated levels of d-dimer are associated with inflammation and disease activity rather than risk of venous thromboembolism in patients with granulomatosis with polyangiitis in long term observation.

PURPOSE: Granulomatosis with polyangiitis (GPA) is one of antineutrophil cytoplasmic autoantibody (ANCA) - associated vasculitis. The disease is characterized by necrotizing inflammation of small vessels causing tissue ischemia in a variety of organs. The aim of the present study was an evaluation of inflammation, coagulation and fibrinolysis biomarkers, and their possible associations with various clinical and laboratory parameters in GPA patients. METHODS: A group of 100 consecutive patients with GPA were prospectively followed in the study. In all patients, echocardiography and laboratory tests were performed. RESULTS: The patients were followed-up for a median of 4.0 ± 1.9 years. Circulating d-dimer concentrations were elevated in a majority (56%) of GPA patients, and were significantly higher in GPA patients in the active stage compared to those in remission (median 652 vs. 405 ng/ml, p = 0.0002). In 23 patients (23%) venous thromboembolism (VTE) was diagnosed during observation. However, there were no differences in d-dimer concentrations between patients with and without VTE either in active stage or in remission. Correlation analysis showed that the levels of d-dimer correlated with hs-CRP (r = 0.42, p < 0.0001) and creatinine concentrations (r = 0.58; p < 0.0001), but not with ANCA levels. CONCLUSIONS: In patients with GPA elevated levels of d-dimer are associated with disease activity and inflammation rather than with the risk of venous thromboembolism. The value of d-dimer as a biomarker of venous thromboembolism episodes in patients with small vessel vasculitis is low.

High incidence of venous thromboembolism but not of coronary artery disease in granulomatosis with polyangiitis in first years after diagnosis.

Objectives: Granulomatosis with polyangiitis (GPA), previously known as Wegener's granulomatosis, is one of antineutrophil cytoplasmic autoantibody (ANCA) - associated vasculitis. In patients with GPA an increased incidence of venous thromboembolism (VTE), mainly during active disease, has been described. The aim of the present study was to assess the incidence of VTE and its relation with classic risk factors for atherosclerosis, presence of coronary artery disease (CAD), echocardiographic parameters and laboratory findings in GPA patients. Methods: The group of consecutive patients with GPA were followed in the study. In all patients echocardiography and laboratory tests were performed. Results: Ninety six patients with GPA were followed for mean 3 years. In 16 patients (16.6%) VTEs occurred in association with GPA, of which 56% occurred 6 months before or one year after diagnosis of GPA. Classic risk factors for atherosclerosis were present in 77 patients (80.2%) at some moment during follow-up. In patients with VTE there were larger right ventricle diameter (p=0.041) and higher right ventricle systolic pressure (p=0.022) observed. VTEs occurred significantly less frequently in patients treated with cyclophosphamide (p=0.049). In this study group VTE occurred more frequently than CAD: 16 (16.7%) vs. 4 (4.2%); p=0,0049. Patients with VTE were younger than those with CAD (p=0.053) and had higher levels of ANCA-PR 3 (p=0.016). Conclusions: Patients with granulomatosis with polyangiitis in first years after diagnosis have higher risk of venous thromboembolism than coronary artery disease. This finding is probably related to hypercoagulability induced by the disease and its therapy.

[Emphysematous cystitis in a patient with type-1diabetes mellitus - diagnostic difficulties].

A case report of 28 year old female with medical history of bed controlled type 1 diabetes mellitus complicated by autonomic neuropathy in the form of gastroparesis, suffered by emphysematous cystitis caused by Escherichia coli was described. Emphysematous cystitis is a rare urinary tract infection connected with the presence of gas in the bladder lumen or/and within the bladder wall, which occurs mainly in women, in older age, suffering from type 2 diabetes, complicated by microangiopathy, neuropathy, with urinary tract obstruction and weakness of immunity system. Diagnostic difficulties and the delay in correct diagnosis in described case were caused by the dominated complaint of the upper gastrointestinal tract and difficulties in interpretation of imaging methods, such as abdominal X-ray and ultrasound scan. Eventually the use of computed tomography allowed to achieved an accurate diagnosis and choose appropriate treatment. It is possible that this is the first case of emphysematous cystitis described in Poland.

SERPINA1 Gene Variants in Granulomatosis with Polyangiitis.

Alpha-1 antitrypsin (A1AT) deficiency is one of the most common genetic disorders in Caucasian population. There is a link between granulomatosis with polyangiitis (GPA) and most frequent variants of SERPINA1 gene encoding severe alpha-1 antitripsin deficiency. However, the potential effect of Pi*Z, Pi*S as well as other SERPINA1 variants on clinical course of vasculitis are not well understood. The aim of the study was to analyze the potential effect of A1AT protein phenotype representing the SERPINA1 gene variants on the clinical course of GPA. The study group consisted of 64 subjects with GPA, stratified according to the disease severity: patients in active phase (group I, n = 12), patients during remission on treatment (group II, n = 40) or untreated (group III, n = 12). Normal Pi*MM SERPINA1 genotype was detected by means of real-time polymerase chain reaction (PCR) or direct sequencing in 59 patients, Pi*MZ genotype in 2, and Pi*IM, Pi*MS or Pi*SZ in 1 patient respectively. The patients with abnormal Pi*Z, Pi*S, or Pi*I allele constituted 17% in group I, 5% in group II, and 8% in group III. The serum content of A1AT and high sensitivity C-reactive protein (hsCRP) assessed by nephelometry did not differ between the groups. Interestingly, the mean serum antiPR3-antibodies level detected by Elisa method was significantly greater in the GPA patients with Pi*Z, Pi*S, or Pi*I SERPINA1 variants than in the Pi*MM homozygotes. In summary, heterozygous Pi*MZ, Pi*MS, and Pi*SZ genotype was detected in 7.8% of total group of GPA patients, and in 10.5% of those with lung lesions. The abnormal alleles of Pi*S and Pi*Z may affect the clinical course of the disease.

Effect of antidepressant treatment on peripheral inflammation markers - A meta-analysis.

INTRODUCTION: Major Depressive Disorder (MDD) in accordance to the inflammatory concept is associated with complex immunological disturbances in the central nervous system (CNS). This is reflected by elevated plasma levels of inflammatory cytokines in depressed subjects. Although numerous studies report significant influence of antidepressants on pro-inflammatory/anti-inflammatory cytokines balance, the available data is often inconsistent regarding specific cytokines and drugs used. We aimed to perform a comprehensive meta-analysis of the effect of antidepressant treatment on a wide array of cytokines. METHODS: We performed a systematic search of 6 databases, which yielded 32 studies measuring the levels of selected cytokines before and at a second time-point during antidepressant treatment. For meta-analysis of selected studies with a continuous measure we analysed variables containing the number of cases, mean and standard deviation of the level of IL-1ß, IL-2, IL-5, IL-6, IL-8, IL-10, CRP, TNF-α, IFN-γ levels observed in the different studies, in the intervention groups before and after antidepressant treatment. RESULTS: Statistical analysis revealed significant decreases of IL-4, IL-6, and IL-10 in MDD subjects after antidepressant treatment. In case of IL-1ß the decrease was significant exclusively for SSRI drugs. We did not find any significant effect of antidepressant medication on IL-2, TNF-α IFN-γ and CRP. CONCLUSIONS: Antidepressant treatment affects the levels of cytokines in depression. The immunological imbalance in MDD is complex and seems to be mediated by other factors yet to be elucidated. The credibility of our results is limited by high heterogeneity among studies and very few studies with a placebo-controlled design. Research with MDD subtypes, response to treatment status and cytokine associations with the kynurenine pathway taken into account pose a promising target for future studies.

Ethylene glycol dimethacrylate and diethylene glycol dimethacrylate exhibits cytotoxic and genotoxic effect on human gingival fibroblasts via induction of reactive oxygen species.

Although methacrylic acid derivatives in their polymeric form are considered to be safe, insufficient polymerization and the release of monomers due to either mechanical or enzymatical factors can lead to their reaching millimolar concentrations in local tissue. The present study evaluates the effect of two methacrylate monomers - ethylene glycol dimethacrylate (EGDMA) and diethylene glycol dimethacrylate (DEGDMA) - on human gingival fibroblasts (HGFs). Both monomers were found to reduce cells viability in MTT assay, increase apoptosis and cause cell cycle arrest in G1/G0 phase. They also increased intracellular reactive oxygen species (ROS) production as measured by DCFH-DA and DHE probes and increased expression of GPx4 and SOD2. Both monomers increased DNA damage in comet assay. Moreover, HGFs were not able to repair those lesions within 120min of repair incubation. However, the monomers were not found to have any effect on the integrity of isolated plasmids. We postulate that EGDMA and DEGDMA exhibit their cytotoxic and genotoxic properties via increased production of ROS, which cause DNA damage, affect apoptosis, viability and cell cycle. Further studies are needed to better understand the properties of methacrylic acid monomers and to evaluate the risk that they cause for patients, dentists and dental technicians.

Decreased expression level of BER genes in Alzheimer's disease patients is not derivative of their DNA methylation status.

BACKGROUND: Neurodegeneration in Alzheimer's disease can be caused by accumulation of oxidative DNA damage resulting from altered expression of genes involved in the base excision repair system (BER). Promoter methylation can affect the profile of BER genes expression. Decreased expression of BER genes was observed in the brains of AD patients. AIM OF THE STUDY: The aim of our study was to compare the expression and methylation profiles of six genes coding for proteins involved in BER, namely: hOGG1, APE1, MUTYH, NEIL1, PARP1 and XRCC1, in the peripheral blood cells of AD patients and healthy volunteers. METHODS: The study consisted of 100 persons diagnosed with Alzheimer's disease according to DSM-IV criteria, and 110 healthy volunteers. DNA and total RNA were isolated from venous blood cells. Promoter methylation profiles were obtained by High Resolution Melting (HRM) analysis of bisulfide converted DNA samples. Real-time PCR with TaqMan probes was employed for gene expression analysis. RESULTS: APE1, hOGG1, MUTYH, PARP1 and NEIL1 were significantly (p<0.001) down-regulated in the lymphocytes of AD patients, as compared to healthy volunteers. Expression of XRCC1 didn't differ significantly between both groups. We did not find any differences in the methylation pattern of any of the investigated BER genes. CONCLUSIONS: The methylation status of promoters is not associated with downregulation of BER genes. Our results show that downregulation of BER genes detected in peripheral blood samples could reflect the changes occurring in the brain of patients with AD, and may be a useful biomarker of this disease.

The Relationship Between Single-Nucleotide Polymorphisms, the Expression of DNA Damage Response Genes, and Hepatocellular Carcinoma in a Polish Population.

The molecular mechanism of hepatocellular carcinoma (HCC) is related to DNA damage caused by oxidative stress products induced by hepatitis B virus (HBV) or C (HCV) infection and exposure to environmental pollutants. Single-nucleotide polymorphisms (SNPs) of DNA damage response (DDR) genes may influence individual susceptibility to environmental risk factors and affect DNA repair efficacy, which, in turn, can influence the risk of HCC. The study evaluates a panel of 15 SNPs in 11 DDR genes (XRCC1, XRCC3, XPD, MUTYH, LIG1, LIG3, hOGG1, PARP1, NFIL1, FEN1, and APEX1) in 65 HCC patients, 50 HBV- and 50 HCV-infected non-cancerous patients, and 50 healthy controls. It also estimates the mRNA expression of nine DDR genes in cancerous and adjacent healthy liver tissues. Two of the investigated polymorphisms (rs1052133 and rs13181) were associated with HCC risk. For all investigated genes, the level of mRNA was significantly lower in HCC cancer tissue than in non-cancerous liver tissue. Seven of the investigated polymorphisms were statistically related to gene expression in cancer tissues. The disruption of DDR genes may be responsible for hepatocellular transformation in HCV-infected patients.

Lung Lesions During Fever of Unknown Origin.

Fever of unknown origin (FUO) remains one of the most difficult diagnostic challenges. The causes of FUO can be various diseases located in different organs. The aim of the study was to determine the prevalence and nature of pulmonary lesions during FUO. One hundred and sixty one patients with FUO participated in this prospective study. We performed a detailed comprehensive history, physical examination, and a wide spectrum of tests. The most common causes of FUO were infections (39%), autoimmune conditions (28%), and neoplasms (17%). Lung lesions were found in 30% of patients. In this group 35% were infections, 30% autoimmune diseases, and 4% cancer. Among patients with respiratory infections, there were cases of tuberculosis, atypical pneumonia, lung abscess, and bronchiectases. Autoimmune pulmonary lesions were observed during vasculitis and systemic lupus. The causes of FUO in the group of patients with lung lesions were also pulmonary embolism, sarcoidosis, and pulmonary fibrosis. Chest CT played an important role in the diagnosis of the causes of FUO with pulmonary manifestations. Pulmonary lesions are a common cause of FUO. Most FUO with pulmonary lesions are recognized during infections and autoimmune diseases. An important part of diagnosing FUO is a detailed evaluation of the respiratory system.

Polymorphism of UBC9 gene encoding the SUMO-E2-conjugating enzyme and breast cancer risk.

UBC9 protein (E2-conjugating enzyme) plays a key role in post-translation modification named sumoylation. Proteins, which are sumoylated take part in many cellular processes including cell growth, maintaining the genome integrity and stability and cancer development. The aim of this study was to investigate an association between three polymorphisms of the UBC9 gene: c.73G>A (rs11553473), c.430T>G (rs75020906) and g.1289209T>C (rs7187167) and a risk of ductal breast cancer occurrence. We performed a case-control study in 181 breast cancer cases and 277 controls using PCR-RLFP and ASO-PCR. In the case of the 430T>G polymorphism of the UBC9 gene lack of variability suggests that there is not a polymorphic site in polish population. We observed that a risk of breast cancer occurrence is elevated in patients with the G/A genotype (OR 5.03; 95% Cl 3.05-8.28), the A/A genotype (OR 11.3; 95% Cl 4.24-30.3) and the A allele (OR 6.86; 95% Cl 4.43-10.6) of the c.73G>A polymorphism. In the case of the g.1289209T>C polymorphism we found a correlation between estrogen receptor (ER) expression and the T/T genotype (OR 0.22; 95% Cl 0.07-0.64) and the T allele (OR 0.53; 95% Cl 0.32-0.88). We also found a correlation between the T/T genotype (OR 4.13; 95% Cl 1.21-14.1) and the T allele (OR 2.09; 95% Cl 1.07-4.08) of the g.1289209T>C polymorphism with triple negative breast cancer. Our results suggest that the variability of the UBC9 gene can play a role in breast cancer occurrence.

Bisphenol A-glycidyl methacrylate induces a broad spectrum of DNA damage in human lymphocytes.

Bisphenol A-glycidyl methacrylate (BisGMA) is monomer of dental filling composites, which can be released from these materials and cause adverse biologic effects in human cells. In the present work, we investigated genotoxic effect of BisGMA on human lymphocytes and human acute lymphoblastic leukemia cell line (CCRF-CEM) cells. Our results indicate that BisGMA is genotoxic for human lymphocytes. The compound induced DNA damage evaluated by the alkaline, neutral, and pH 12.1 version of the comet assay. This damage included oxidative modifications of the DNA bases, as checked by DNA repair enzymes EndoIII and Fpg, alkali-labile sites and DNA double-strand breaks. BisGMA induced DNA-strand breaks in the isolated plasmid. Lymphocytes incubated with BisGMA at 1 mM were able to remove about 50% of DNA damage during 120-min repair incubation. The monomer at 1 mM evoked a delay of the cell cycle in the S phase in CCRF-CEM cells. The experiment with spin trap-DMPO demonstrated that BisGMA induced reactive oxygen species, which were able to damage DNA. BisGMA is able to induce a broad spectrum of DNA damage including severe DNA double-strand breaks, which can be responsible for a delay of the cell cycle in the S phase.

Independent and combined cytotoxicity and genotoxicity of triethylene glycol dimethacrylate and urethane dimethacrylate.

Dental composite materials contain polymers of methacrylates, which, due to mechanical abrasion and enzymatic action of saliva, may release their monomers into oral cavity and the pulp. Moreover, polymerization is always incomplete and leaves usually considerable fraction of free monomers. Mechanisms of the genotoxicity of methacrylate monomers have been rarely explored. As the polymerization of a monomer is catalyzed by a co-monomer, their combined action should be considered. In the present work, we investigated cytotoxic and genotoxic effects of urethane dimethacrylate (UDMA), often used as a monomer, at 1 mM, and triethylene glycol dimethacrylate (TEGDMA), a typical co-monomer, at 5 mM singly and in combination. Experiments were conducted on Chinese hamster ovary cells. Cell viability, apoptosis and cell cycle were assessed by flow cytometry, whereas DNA damage was evaluated by plasmid conformation test and comet assay. Both compounds decreased the viability of the cells, but did not induce strand breaks in an isolated plasmid DNA. However, both substances, either singly or in combination, damaged DNA in CHO cells as evaluated by comet assay. Both compounds induced apoptosis, but a combined action of them led to a decrease in the number of apoptotic cells. The combined action of UDMA and TEGDMA in the disturbance of cell cycle was lesser compared to the action of each compound individually. Individually, though UDMA and TEGDMA may induce cytotoxic and genotoxic, however, a combination of both does not produce a significant increase in these effects.

Polymorphisms in RAD51, XRCC2 and XRCC3 genes of the homologous recombination repair in colorectal cancer--a case control study.

XRCC2 and XRCC3 proteins are structurally and functionally related to RAD51 which play an important role in the homologous recombination, the process frequently involved in cancer transformation. In our previous work we show that the 135G>C polymorphism (rs1801320) of the RAD51 gene can modify the effect of the Thr241Met polymorphism (rs861539) of the XRCC3 gene. We tested the association between the 135G>C polymorphism of the RAD51 gene, the Thr241Met polymorphism of the XRCC3 gene and the Arg188His polymorphism (rs3218536) of the XRCC2 gene and colorectal cancer risk and clinicopathological parameters. Polymorphisms were evaluated by restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR) in 100 patients with invasive adenocarcinoma of the colon and in 100 sex, age and ethnicity matched cancer-free controls. We stratified the patients by genotypes, tumour Duke's and TNM stage and calculated the linkage of each genotype with each stratum. Carriers of Arg188Arg/Me241tMet, His188His/Thr241Thr and His188His/G135G genotypes had an increased risk of colorectal cancer occurrence (OR 5.70, 95% CI 1.10-29.5; OR 12.4, 95% CI 1.63-94.9; OR 5.88, 95% CI 1.21-28.5, respectively). The C135C genotype decreased the risk of colorectal cancer singly (OR 0.06, 95% CI 0.02-0.22) as well as in combination with other two polymorphisms. TNM and Duke's staging were not related to any of these polymorphisms. Our results suggest that the 135G>C polymorphism of the RAD51 gene can be an independent marker of colorectal cancer risk. The Thr241Met polymorphism of the XRCC3 gene and the Arg188His polymorphism of the XRCC2 gene can modify the risk of colorectal cancer.

Cytotoxicity and genotoxicity of capecitabine in head and neck cancer and normal cells.

The interaction between a chemical and a cell may strongly depend on whether this cell is normal or pathological. Side effects of anticancer drugs may sometimes overcome their benefit action, so it is important to investigate their effect in both the target and normal cells. Capecitabine (Xeloda, CAP), a prodrug of 5-fluorouracil, is mainly used in colon cancer, but little is known about its action in head and neck cancer. We compared the cyto- and genotoxicity of CAP in head and neck HTB-43 cells and normal human lymphocytes by comet assay and flow cytometry. CAP at concentration up to 50 µM significantly decreased the viability of the cancer cells, whereas it did not affect normal lymphocytes. The drug did not interact with isolated plasmid DNA, but it damaged DNA in both cancer and normal cells. However, the extent of the damage in the former was much higher than in the latter. CAP induced apoptosis in the cancer cells, but not in normal lymphocytes. Pre-treatment of the cells with the nitrone spin traps α-(4-pyridil-1-oxide)-N-tert-butylnitrone and N-tert-butyl-α-phenylnitrone decreased the extent of CAP induced DNA damage, suggesting that free radicals may be involved in the formation of DNA lesions induced by CAP. The drug evoked an increase in the G0/G1 cell population accompanied by a decrease in the S cell population. CAP may evoke a pronounced cyto- and genotoxic effects in head and neck cancer cells, whereas it may or may not induce such effects in normal cells to far lesser extent.

DNA damage and repair in endometrial cancer in correlation with the hOGG1 and RAD51 genes polymorphism.

The cellular reaction to the DNA-damaging agents may modulate individual's cancer susceptibility. This reaction is mainly determined by the efficacy of DNA repair, which in turn, may be influenced by the variability of DNA repair genes, expressed by their polymorphism. The hOGG1 gene encodes a glycosylase of base excision repair and RAD51 specifies a key protein in homologues recombination repair. Both proteins can be involved in the repair of DNA lesions, which are known to contribute to endometrial cancer. In the present work we determined the extent of basal DNA damage and the efficacy of removal of DNA damage induced by hydrogen peroxide and N-methyl-N'-nitro N-nitrosoguanidyne (MNNG) in peripheral blood lymphocytes of 30 endometrial cancer patients and 30 individuals without cancer. The results from DNA damage and repair study were correlated with the genotypes of two common polymorphisms of the hOGG1 and RAD51 genes: a G>C transversion at 1245 position of the hOGG1 gene producing a Ser → Cys substitution at the codon 326 (the Ser326Cys polymorphism) and a G>C substitution at 135 position of the RAD51 gene (the 135G>C polymorphism). DNA damage and repair were evaluated by alkaline single cell gel electrophoresis and genotypes were determined by restriction fragment length polymorphism PCR. We observed a strong association between endometrial cancer and the C/C genotype of the 135G>C polymorphism of the RAD51 gene. Moreover, there was a strong correlation between that genotype and endometrial cancer occurrence in subjects with a high level of basal DNA damage. We did not observe any correlation between the Ser326Cys polymorphism of the hOGG1 gene and endometrial cancer. Our result suggest that the 135G>C polymorphism of the RAD51 gene may be linked to endometrial cancer and can be considered as an additional marker of this disease.

Efficacy of DNA double-strand breaks repair in breast cancer is decreased in carriers of the variant allele of the UBC9 gene c.73G>A polymorphism.

UBC9 (E2) SUMO conjugating enzyme plays an important role in the maintenance of genome stability and integrity. In the present work we examined the association between the c.73G>A (Val25Met) polymorphism of the UBC9 gene (rs11553473) and efficacy of DNA double-strand breaks (DSBs) repair (DRE) in breast cancer patients. We determined the level of endogenous (basal) and exogenous (induced by γ-irradiation) DSBs and efficacy of their repair in peripheral blood lymphocytes of 57 breast cancer patients and 70 healthy individuals. DNA damage and repair were studied by neutral comet assay. Genotypes were determined in DNA from peripheral blood lymphocytes by allele-specific PCR (ASO-PCR). We also correlated genotypes with the clinical characteristics of breast cancer patients. We observed a strong association between breast cancer occurrence and the variant allele carried genotypes in patients with elevated level of basal as well as induced DNA damage (OR 6.74, 95% CI 2.27-20.0 and OR 5.33, 95% CI 1.81-15.7, respectively). We also found statistically significant (p<0.05) difference in DRE related to the c.73G>A polymorphism of the UBC9 gene in breast cancer patients. Carriers of variant allele have decreased DNA DRE as compared to wild type genotype carriers. We did not find any association with the UBC9 gene polymorphism and estrogen and progesterone receptor status. The variant allele of the UBC9 gene polymorphism was strongly inversely related to HER negative breast cancer patients (OR 0.03, 95% CI 0.00-0.23). Our results suggest that the c.73G>A polymorphism of the UBC9 gene may affect DNA DSBs repair efficacy in breast cancer patients.

[The role of RAD 51 gene polymorphism in patients with colorectal cancer in the Polish subpopulation]. / Rola polimorfizmu genu RAD51 u chorych z rakiem jelita grubego w subpopulacji polskiej.

UNLABELLED: DNA repair processes assure genomic integrity and play the crucial role in protecting against carcinogenic factors. Mutations in DNA repair genes, which code proteins engaged in repair processes, may lead to carcinogenesis and among others also to colorectal cancer development. RAD51 gene encodes a protein of DNA homologues recombination repair. AIM OF THE STUDY: To evaluate the role of RAD51 gene polymorphism in patients with colorectal cancer in Polish subpopulation Materials and methods. The studied group comprised 100 colorectal cancer patients (aged 57-75) and 236 age, sex-, age- and ethnicity-matched cancer-free controls. Genotypes were determined in DNA from peripheral blood lymphocytes by PCR-RFLP. RESULTS: An association between colorectal cancer occurrence and the G/C variant of the 135 G/C RAD51 polymorphism was found (OR 2.45; 95% CI 1,45-4,14) (p > 0.05). CONCLUSIONS: The G/C variant of the 135 G/C RAD51 polymorphism may be associated with the increased risk of colorectal cancer development.