Metabolomics Meets Clinics: A Multivariate Analysis of Plasma and Urine Metabolic Signatures in Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is a severe, multifactorial, and frequently misdiagnosed disorder. The aim of this observational study was to compare the plasma and urine metabolomic profiles of PAH patients and healthy control subjects. Plasma and urine metabolomic profiles were analyzed using the GC-MS technique. Correlations between metabolite levels and clinical parameters among PAH patients, as well as the between-group differences, were evaluated. The linear discriminant analysis model, which allows for subject classification in terms of PAH with the highest possible precision, was developed and proposed. Plasma pyruvic acid, cholesterol, threonine, urine 3-(3-hydroxyphenyl)-3-hydroxypropanoic acid, butyric acid, 1,2-benzenediol, glucoheptonic acid, and 2-oxo-glutaric acid were found to build a relatively accurate classification model for PAH patients. The model reached an accuracy of 91% and significantly improved subject classification (OR = 119 [95% CI: 20.3-698.3], p < 0.0001). Five metabolites were detected in urine that provide easily available and noninvasive tests as compared to right heart catheterization. The selected panel of metabolites has potential for early recognition of patients with dyspnea and faster referral to a reference center.

Long-term mortality after transcatheter aortic valve implantation for aortic stenosis in immunosuppression-treated patients: a propensity-matched multicentre retrospective registry-based analysis.

Introduction: Data regarding patients with a previous medical record of immunosuppression treatment who have undergone transcatheter aortic valve implantation (TAVI) are limited and extremely inconclusive. Available studies are mostly short term observations; thus there is a lack of evidence on efficacy and safety of TAVI in this specific group of patients. Aim: To compare the in-hospital and long-term outcomes between patients with or without a medical history of immunosuppressive treatment undergoing TAVI for aortic valve stenosis (AS). Material and methods: We conducted a retrospective registry-based analysis including patients undergoing TAVI for AS at 5 centres between January 2009 and August 2017. The primary endpoint was long-term all-cause mortality. Secondary endpoints comprised major vascular complications, life-threatening or disabling bleeding, stroke and new pacemaker implantation. Results: Of 1451 consecutive patients who underwent TAVI, two propensity-matched groups including 25 patients with a history of immunosuppression and 75 patients without it were analysed. No differences between groups in all-cause mortality were found in a median follow-up time of 2.7 years following TAVI (p = 0.465; HR = 0.73; 95% CI: 0.30-1.77). The rate of major vascular complications (4.0% vs. 5.3%) was similar in the two groups (p = 1.000). There were no statistically significant differences in the composite endpoint combining life-threatening or disabling bleeding, major vascular complications, stroke and new pacemaker implantation (40.0% vs. 20.0%, p = 0.218). Conclusions: Patients who had undergone TAVI for AS had similar long-term mortality regardless of whether they had a previous medical record of immunosuppression. Procedural complication rates were comparable between the groups.

Plasma Proteomics Unveil Novel Immune Signatures and Biomarkers upon SARS-CoV-2 Infection.

Several elements have an impact on COVID-19, including comorbidities, age and sex. To determine the protein profile changes in peripheral blood caused by a SARS-CoV-2 infection, a proximity extension assay was used to quantify 1387 proteins in plasma samples among 28 Finnish patients with COVID-19 with and without comorbidities and their controls. Key immune signatures, including CD4 and CD28, were changed in patients with comorbidities. Importantly, several unreported elevated proteins in patients with COVID-19, such as RBP2 and BST2, which show anti-microbial activity, along with proteins involved in extracellular matrix remodeling, including MATN2 and COL6A3, were identified. RNF41 was downregulated in patients compared to healthy controls. Our study demonstrates that SARS-CoV-2 infection causes distinct plasma protein changes in the presence of comorbidities despite the interpatient heterogeneity, and several novel potential biomarkers associated with a SARS-CoV-2 infection alone and in the presence of comorbidities were identified. Protein changes linked to the generation of SARS-CoV-2-specific antibodies, long-term effects and potential association with post-COVID-19 condition were revealed. Further study to characterize the identified plasma protein changes from larger cohorts with more diverse ethnicities of patients with COVID-19 combined with functional studies will facilitate the identification of novel diagnostic, prognostic biomarkers and potential therapeutic targets for patients with COVID-19.

Breast cancer circulating tumor cells with mesenchymal features-an unreachable target?

Circulating tumor cells (CTCs) mediate dissemination of solid tumors and can be an early sign of disease progression. Moreover, they show a great potential in terms of non-invasive, longitudinal monitoring of cancer patients. CTCs have been extensively studied in breast cancer (BC) and were shown to present a significant phenotypic plasticity connected with initiation of epithelial-mesenchymal transition (EMT). Apart from conferring malignant properties, EMT affects CTCs recovery rate, making a significant portion of CTCs from patients' samples undetected. Wider application of methods and markers designed to isolate and identify mesenchymal CTCs is required to expand our knowledge about the clinical impact of mesenchymal CTCs. Therefore, here we provide a comprehensive review of clinical significance of mesenchymal CTCs in BC together with statistical analysis of previously published data, in which we assessed the suitability of a number of methods/markers used for isolation of CTCs with different EMT phenotypes, both in in vitro spike-in tests with BC cell lines, as well as clinical samples. Results of spiked-in cell lines indicate that, in general, methods not based on epithelial enrichment only, capture mesenchymal CTCs much more efficiently that CellSearch® (golden standard in CTCs detection), but at the same time are not much inferior to Cell Search®, though large variation in recovery rates of added cells among the methods is observed. In clinical samples, where additional CTCs detection markers are needed, positive epithelial-based CTCs enrichment was the most efficient in isolating CTCs with mesenchymal features from non-metastatic BC patients. From the marker side, PI3K and VIM were contributing the most to detection of CTCs with mesenchymal features (in comparison to SNAIL) in non-metastatic and metastatic BC patients, respectively. However, additional data are needed for more robust identification of markers for efficient detection of CTCs with mesenchymal features.

Transcriptomic landscape of blood platelets in healthy donors.

Blood platelet RNA-sequencing is increasingly used among the scientific community. Aberrant platelet transcriptome is common in cancer or cardiovascular disease, but reference data on platelet RNA content in healthy individuals are scarce and merit complex investigation. We sought to explore the dynamics of platelet transcriptome. Datasets from 204 healthy donors were used for the analysis of splice variants, particularly with regard to age, sex, blood storage time, unit of collection or library size. Genes B2M, PPBP, TMSB4X, ACTB, FTL, CLU, PF4, F13A1, GNAS, SPARC, PTMA, TAGLN2, OAZ1 and OST4 demonstrated the highest expression in the analysed cohort, remaining substantial transcription consistency. CSF3R gene was found upregulated in males (fold change 2.10, FDR q < 0.05). Cohort dichotomisation according to the median age, showed upregulated KSR1 in the older donors (fold change 2.11, FDR q < 0.05). Unsupervised hierarchical clustering revealed two clusters which were irrespective of age, sex, storage time, collecting unit or library size. However, when donors are analysed globally (as vectors), sex, storage time, library size, the unit of blood collection as well as age impose a certain degree of between- and/or within-group variability. Healthy donor platelet transcriptome retains general consistency, with very few splice variants deviating from the landscape. Although multidimensional analysis reveals statistically significant variability between and within the analysed groups, biologically, these changes are minor and irrelevant while considering disease classification. Our work provides a reference for studies working both on healthy platelets and pathological conditions affecting platelet transcriptome.

Environmental exposure to persistent organic pollutants measured in breast milk of lactating women from an urban area in central Poland.

Mothers' milk is considered a channel by means of which new-borns are exposed to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dl-PCBs), environmental pollutants entering food chain and accumulating in fat-rich tissues. In this study, the concentrations of selected PCDDs, PCDFs, and dl-PCBs (a total of 29 substances) in milk samples of 110 breast-feeding women from an urban area were analyzed using the high-resolution gas chromatography/high-resolution mass spectrometry method. Environmental exposure to these substances was expressed by means of the World Health Organization Toxicity Equivalent (WHO-TEQ2005) using the Toxicity Equivalent Factor values from van der Berg et al. (Toxicol. Sci. 93: 223-241, 2006). Concentrations and WHO-TEQ2005 values were then searched for plausible relationships with selected demographic and diet-related factors. The total WHO-TEQ2005 toxicity equivalent for all 29 substances was (mean ± SD) 10.57 ± 4.57 pg/g fat, while the WHO-TEQ2005 levels of PCDDs/PCDFs and dl-PCBs were 7.90 ± 4.17 pg/g fat and 2.67 ± 1.36 pg/g fat, respectively. The concentration and WHO-TEQ2005 toxicity equivalent of dl-PCBs correlated significantly with the mothers' age (rP = 0.3814, p < 0.00005; rP = 0.2817, p < 0.005, respectively). The total WHO-TEQ2005 toxicity equivalent for all analyzed substances was found to be positively associated with the frequency of consumption of fish and dairy products (p < 0.05 for both associations). These outcomes must, however, be interpreted cautiously due to limited size of the study. The results of this paper may provide a basis for further studies on the exposure to PCDDs, PCDFs, and dl-PCBs, and mechanisms underlying their action.

Blood plasma levels of biomarkers of liver status and lipid profile among nail technicians occupationally exposed to low-level mixture of volatile organic compounds.

PURPOSE: Nail technicians (NTs) are exposed to a low-level mixture of volatile organic solvents (VOCs), yet the health hazards related to such exposure are unknown. This study thus aimed to compare the blood plasma levels of selected biomarkers related to liver status and lipid profile among occupationally exposed NTs and unexposed controls. Associations between out-of-normal-range levels of such biomarkers and occupational exposure to VOCs mixture have also been investigated. METHODS: The study enrolled 145 female NTs and 152 unexposed controls. Biochemical analyses were performed using spectrophotometric assays and obtained data were analyzed using general linear model and Poisson regression modelling adjusted to multiple confounders. RESULTS: Compared to controls, NTs presented significantly increased plasma activities of ALT (2.04 ± 0.63 ln-U/l vs. 1.25 ± 0.71 ln-U/l; p < 0.0001) and AST (2.73 ± 0.25 ln-U/l vs. 2.08 ± 0.95 ln-U/l; p < 0.0001), and significantly increased plasma levels of TG (4.38 ± 0.53 ln-mg/dl vs. 4.21 ± 0.42 ln-mg/dl; p < 0.05) and TC/HDL ratio (1.18 ± 0.36 vs. 1.02 ± 0.27; p < 0.0005). Plasma levels of HDL were significantly lower among NTs (4.02 ± 0.29 ln-mg/dl vs. 4.21 ± 0.26 ln-mg/dl; p < 0.0001). Moreover, NTs were found to present significantly increased risk of occurrence of clinically relevant plasma HDL levels below 3.91 ln-mg/dl (i.e., 50 mg/dl; RR = 1.58, 95% CI 1.07-2.32, p < 0.05), as well as increased risk of clinically relevant TC/HDL ratio above the normal range limit of 3.5 (RR = 1.68, 95% CI 1.19-2.35, p < 0.005), as compared to unexposed controls. CONCLUSION: Nail technicians are subject to adverse changes in selected plasma biomarkers related to liver functions, some of which may be of clinical relevance.

Rad51 paralogs and the risk of unselected breast cancer: A case-control study.

A case-control study was conducted in which we evaluated the association between genetic variability of DNA repair proteins belonging to the Rad51 family and breast cancer (BrC) risk. In the study, 132 female BrC cases and 189 healthy control females were genotyped for a total of 14 common single nucleotide polymorphisms (SNPs) within Rad51 and Xrcc3. Moreover, our previously reported Rad51C genetic data were involved to explore the nonlinear interactions among SNPs within the three genes and effect of such interactions on BrC risk. The rare rs5030789 genotype (-4601AA) in Rad51 was found to significantly decrease the BrC risk (OR = 0.5, 95% CI: 0.3-1.0, p<0.05). An interaction between this SNP, rs2619679 and rs2928140 (both in Rad51), was found to result in a two three-locus genotypes -4719AA/-4601AA/2972CG and -4719AT/-4601GA/2972CC, both of which were found to increase the risk of BrC (OR = 8.4, 95% CI: 1.8-38.6, p<0.0001), instead. Furthermore, rare Rad51 rs1801320 (135CC) and heterozygous Xrcc3 rs3212057 (10343GA) genotypes were found to respectively increase (OR = 10.6, 95% CI: 1.9-198, p<0.02) and decrease (OR = 0.0, 95% CI: 0.0-NA, p<0.05) the risk of BrC. Associations between these SNPs and BrC risk were further supported by outcomes of employed machine learning analyses. In Xrcc3, the 4541A/9685A haplotype was found to be significantly associated with reduced BrC risk (OR = 0.5; 95% CI: 0.3-0.9; p<0.05). Concluding, our study indicates a complex role of SNPs within Rad51 (especially rs5030789) and Xrcc3 in BrC, although their significance with respect to the disease needs to be further clarified.

The ESR1 and GPX1 gene expression level in human malignant and non-malignant breast tissues.

BACKGROUND: The aim of this study was to establish whether the gene expression of estrogen receptor alpha (encoded by ESR1) correlates with the expression of glutathione peroxidase 1 (encoded by GPX1) in the tumor and adjacent tumor-free breast tissue, and whether this correlation is affected by breast cancer. Such relationships may give further insights into breast cancer pathology with respect to the status of estrogen receptor. METHODS: We used the quantitative real-time PCR technique to analyze differences in the expression levels of the ESR1 and GPX1 genes in paired malignant and non-malignant tissues from breast cancer patients. RESULTS: ESR1 and GPX1 expression levels were found to be significantly down-regulated by 14.7% and 7.4% (respectively) in the tumorous breast tissue when compared to the non-malignant one. Down-regulation of these genes was independent of the tumor histopathology classification and clinicopathological factors, while the ESR1 mRNA level was reduced with increasing tumor grade (G1: 103% vs. G2: 85.8% vs. G3: 84.5%; p<0.05). In the non-malignant and malignant breast tissues, the expression levels of ESR1 and GPX1 were significantly correlated with each other (Rs=0.450 and Rs=0.360; respectively). CONCLUSION: Our data suggest that down-regulation of ESR1 and GPX1 was independent of clinicopathological factors. Down-regulation of ESR1 gene expression was enhanced by the development of the disease. Moreover, GPX1 and ESR1 gene expression was interdependent in the malignant breast tissue and further work is needed to determine the mechanism underlying this relationship.

Faster health deterioration among nail technicians occupationally exposed to low levels of volatile organic compounds.

OBJECTIVES: The study has aimed at investigating the subjective assessment of an individual's health status and comparing the prevalence of selected work-related symptoms among nail technicians occupationally exposed to volatile organic compounds (VOCs) to the one among control subjects. Associations between occupational exposure to VOCs and the incidence of adverse health effects were also analyzed. MATERIAL AND METHODS: The study involved 145 female nail technicians and 152 control subjects. Data on the prevalence of adverse health effects was collected using the researcher- made questionnaire and then analyzed by means of survival analysis methods. RESULTS: Only 22% of nail technicians as compared to 45% of control subjects described their current health status as "excellent" or "very good" (odds ratio (OR) = 0.4, 95% confidence interval (CI): 0.2-0.6, p < 0.00005). In general, 61% of nail technicians confirmed to have experienced any out of all symptoms considered in the study since the commencement of the job, which was significantly higher as compared to 17% of control subjects (adjusted OR = 2.8, 95% CI: 2.1-3.7, p < 0.0001). Estimated median length of the employment period free of investigated symptoms was significantly shorter among nail technicians as compared to controls (12 years vs. 33 years, p < 0.0001), consistent with almost 4-times increased hazard of the occurrence of such symptoms among the technicians (hazard ratio (HR) = 3.9, 95% CI: 2.7-5.7, p < 0.0001). Cox proportional hazard regression modeling revealed almost 5-times increased hazard of the occurrence of any symptoms among nail technicians exposed to higher levels of the mixture of VOCs as compared to those exposed to lower levels (HR = 4.9, 95% CI: 1-24.1, p = 0.05). CONCLUSIONS: All outcomes combined together indicate that nail technicians are subject to faster health deterioration, which may be assumed to be caused by occupational exposure to low levels of VOCs. Int J Occup Med Environ Health 2017;30(3):469-483.

Does the Low-level occupational exposure to volatile organic compounds alter the seasonal variation of selected markers of oxidative stress? A case-control study in nail technicians.

BACKGROUND: In this study we tested whether the seasonal variations in levels of selected biomarkers of oxidative stress in female nail technicians occupationally exposed to low levels of volatile organic compounds (VOCs) differ significantly from those observed among healthy unexposed controls. Airborne levels of selected VOCs in nail salons were also analyzed and tested for associations with seasonal variations of the levels of biomarkers among nail technicians. METHODS: The study enrolled 145 female nail technicians and 145 healthy unexposed female controls. The airborne VOCs and levels of biomarkers were assessed by GC-MS chromatography and absorption/fluorescence spectrophotometry, respectively. RESULTS: Plasma levels of thiobarbituric acid reactive species, ceruloplasmin, the activity of glutathione peroxidase (GPx1) and the SOD1/GPx1 activity ratio presented significant differences between the so-called "hot" and "cold" seasons in the case of nail technicians as well as in unexposed controls (p < <0.0001 for all four biomarkers). The pattern of these variations among nail technicians was found to be significantly different compared to that of the control subjects (p < <0.0001). Although such differences might intuitively be attributed to occupational exposure of nail technicians to VOCs, which was found to be higher during the "cold" season compared to the "hot" one, our study provided only limited evidence in favor of the hypothesis, that the different pattern of seasonal variations of biomarkers among nail technicians might have resulted from seasonal fluctuations in their occupational exposure to VOCs. CONCLUSION: Further investigation is thus needed in order to elucidate the effect of low-level occupational exposure to VOCs on seasonal variations of biomarkers of oxidative stress.

Lipid peroxidation and glutathione peroxidase activity relationship in breast cancer depends on functional polymorphism of GPX1.

BACKGROUND: Since targeting oxidative stress markers has been recently recognized as a novel therapeutic target in cancer, it is interesting to investigate whether genetic susceptibility may modify oxidative stress response in cancer. The aim of this study was to elucidate whether genetic polymorphism in the antioxidant enzymes is associated with lipid peroxidation in breast cancer. METHODS: We conducted a study among Polish women, including 136 breast cancer cases and 183 healthy controls. The analysis included genetic polymorphisms in five redox related genes: GPX1 (rs1050450), GPX4 (rs713041), SOD2 (rs4880), SEPP1 (rs3877899) and SEP15 (rs5859), lipid peroxidation, the activities of antioxidant enzymes determined in blood compartments as well as plasma concentration of selenium - an antioxidant trace element involved in cancer. Genotyping was performed using the Real Time PCR. Lipid peroxidation was expressed as plasma concentration of thiobarbituric acid reactive substances (TBARS) and measured with the spectrofluorometric method. Glutathione peroxidase activity was spectrophotometrically determined in erythrocytes (GPx1) and plasma (GPx3) by the use of Paglia and Valentine method. Spectrophotometric methods were employed to measure activity of cytosolic superoxide dismutase (SOD1) in erythrocytes (Beauchamp and Fridovich method) and ceruloplasmin (Cp) in plasma (Sunderman and Nomoto method). Plasma selenium concentration was determined using graphite furnace atomic absorption spectrophotometry. RESULTS: Breast cancer risk was significantly associated with GPX1 rs1050450 (Pro198Leu) polymorphism, showing a protective effect of variant (Leu) allele. As compared to the control subjects, lipid peroxidation and GPx1 activity were significantly higher in the breast cancer cases, whereas ceruloplasmin activity was decreased. After genotype stratification, both GPx1 activity and TBARS concentration were the highest in GPX1 Pro/Pro homozygotes affected by breast cancer. At the same time, there was a significant correlation between the level of lipid peroxidation and GPx1 activity among the cancer subjects possessing GPX1 Pro/Pro genotype (r = 0.3043; p = 0.0089), whereas such a correlation was completely absent in the cases carrying at least one GPX1 Leu allele as well as in the controls (regardless of GPX1 genotype). CONCLUSIONS: GPX1 polymorphism may be an important factor modifying oxidative stress response in breast cancer subjects. Further studies are needed to elucidate its potential clinical significance.

Dysregulation of markers of oxidative stress and DNA damage among nail technicians despite low exposure to volatile organic compounds.

OBJECTIVE: The study aimed to compare levels of selected biomarkers of oxidative stress and DNA damage and their correlation with occupational exposure to volatile organic compounds (VOC) among female nail technicians and a group of unexposed volunteers. METHODS: A panel of biomarkers of oxidative stress and DNA damage was assayed among 145 female nail technicians and 152 healthy female volunteers. Occupational exposure of nail technicians to VOC was assessed analyzing the VOC content in nail salon air samples. RESULTS: The level of occupational exposure of nail technicians to VOC was below the respective threshold limit values with combined airborne exposure to a mixture of VOC, reaching only 3.3% (range 0.2-33.3%) of the threshold limit. Despite that, nail technicians presented increased activity of glutathione peroxidase 1 (GPx1), plasma ceruloplasmin, and the GPx1/superoxide dismutase 1 ratio (P<0.0001). The levels of plasma thiobarbituric acid-reactive species and DNA strand breakage in blood leukocytes were not significantly different. In contrast, total and oxidatively-generated DNA damage were significantly decreased among nail technicians compared to controls (P<0.0001). The individual's current tobacco smoking and alcohol consumption status did not modulate the observed changes. Significant correlations between selected biomarkers of oxidative stress, DNA damage, and airborne levels of VOC (eg, ethanol) were found. CONCLUSIONS: The levels of biomarkers of oxidative stress and DNA damage among nail technicians seem to be dysregulated despite the low level of occupational exposure to VOC. Although the outcomes are not fully conclusive, our findings point to possible causation related to prolonged low-level occupational exposure to VOC.

Single nucleotide polymorphisms in noncoding regions of Rad51C do not change the risk of unselected breast cancer but they modulate the level of oxidative stress and the DNA damage characteristics: a case-control study.

Deleterious and missense mutations of RAD51C have recently been suggested to modulate the individual susceptibility to hereditary breast and ovarian cancer and unselected ovarian cancer, but not unselected breast cancer (BrC). We enrolled 132 unselected BrC females and 189 cancer-free female subjects to investigate whether common single nucleotide polymorphisms (SNPs) in non-coding regions of RAD51C modulate the risk of BrC, and whether they affect the level of oxidative stress and the extent/characteristics of DNA damage. Neither SNPs nor reconstructed haplotypes were found to significantly affect the unselected BrC risk. Contrary to this, carriers of rs12946522, rs16943176, rs12946397 and rs17222691 rare-alleles were found to present significantly increased level of blood plasma TBARS compared to respective wild-type homozygotes (p<0.05). Furthermore, these carriers showed significantly decreased fraction of oxidatively generated DNA damage (34% of total damaged DNA) in favor of DNA strand breakage, with no effect on total DNA damage, unlike respective wild-types, among which more evenly distributed proportions between oxidatively damaged DNA (48% of total DNA damage) and DNA strand breakage was found (p<0.0005 for the difference). Such effects were found among both the BrC cases and healthy subjects, indicating that they cannot be assumed as causal factors contributing to BrC development.

Rad51C: a novel suppressor gene modulates the risk of head and neck cancer.

We conducted a case-control study to investigate the possible association between the head and neck cancer (HNC) and genetic variability of Rad51C tumor suppressor gene. Eight polymorphic sites spanning over non-coding regions of Rad51C promoter, exon 1 and intron 1 were genotyped in 81 HNC cases and 156 healthy controls using the real-time PCR technique. One investigated site turned out to be not polymorphic, while among the remaining seven sites a significant HNC risk-increasing effect was found for rs16943176 (c.-118G>A), rs12946397 (c.-26C>T) and rs17222691 (c.145+947C>T) on both allelic (OR=1.8; p<0.05) and genotypic (OR=2.0; p<0.05) level. Furthermore, our data seem to provide marginal evidence, that this effect might possibly be confined to women only (OR=2.8; p=0.05 for allelic and OR=3.7; p=0.05 for genotypic comparisons). These SNPs were found to co-segregate together forming two distinct, HNC risk-modulating haplotypes. The genetic variability of Rad51C might thus be of relevance with respect to HNC risk.

Genetic variability of Xrcc3 and Rad51 modulates the risk of head and neck cancer.

A case-control study was conducted to analyze the possible associations between the head and neck cancer (HNC) risk and fourteen single nucleotide polymorphisms (SNPs) and haplotypes in Xrcc3 and Rad51 genes. This study involved 81 HNC cases and 111 healthy control subjects. A significant risk-increasing effect of rs3212057 (p.Arg94His) SNP in Xrcc3 (OR=6.6; p<0.01) was observed. On the other hand, risk-decreasing effect was found for rs5030789 (g.3997A>G) and rs1801321 (c.-60G>T) in 5' near gene and 5'UTR regions of Rad51, respectively (OR=0.3 and OR=0.2, p<0.05, respectively). Moreover, these effects were shown to be modulated by tobacco-smoking status and gene-gene interactions. Concluding, the genetic variability of Xrcc3 and/or Rad51 genes might be of relevance with respect to HNC risk.

Reference genes for gene expression studies on non-small cell lung cancer.

STUDY OBJECTIVE: The aim of this study was to test a panel of 6 reference genes in order to identify and validate the most suitable reference genes for expression studies in paired healthy and non-small cell lung cancer tissues. METHOD: Quantitative real-time PCR followed by the NormFinder- and geNorm-based analysis was employed. The study involved 21 non-small cell lung cancer patients. RESULTS: The analysis of experimental data revealed HPRT1 as the most stable gene followed by RPLP0 and ESD. In contrast, GAPDH was found to be the least stable gene. HPRT1 together with ESD was revealed as the pair of genes introducing the least systematic error into data normalization. Validation by bootstrap random sampling technique and by normalizing exemplary gene expression data confirmed the results. CONCLUSION: Although HPRT1 and ESD may by recommended for data normalization in gene expression studies on non-small cell lung cancer, the suitability of selected reference genes must be unconditionally validated prior to each study.

Expression of selenoprotein-coding genes SEPP1, SEP15 and hGPX1 in non-small cell lung cancer.

Aim of the study was to investigate the mRNA expression level of selenoprotein P (SEPP1), 15-kDa selenoprotein (SEP15) and glutathione peroxidase 1 (hGPX1) in paired malignant and non-malignant tissue. To achieve this goal, the quantitative real-time PCR technique was utilized in paired tissue samples from 33 non-small cell lung cancer (NSCLC) patients. Simultaneously, the activity of glutathione peroxidases (GPX) and the level of thiobarbituric acid-reactive species (TBARS) in paired tissue specimens and the blood plasma selenium level was measured. We found significant down-regulation of SEPP1 expression level in tumorous lung tissue (2.732-fold; p<0.001). The expression of hGPX1 and SEP15 in tumorous tissue remained unchanged compared to healthy tissue. The level of TBARS in malignant tissue was significantly increased (p<0.005) and negatively correlated with SEPP1 expression level (R(S)=-0.3238; p<0.05). The activity of GPX in malignant tissue was significantly increased compared to the non-malignant one (p<0.005) and negatively correlated with the expression level of SEPP1. It seems possible, that the down-regulation of SEPP1 expression may lead to an increased oxidative stress possibly resulting in lung carcinogenesis. Increased activity of GPX in tumorous lung tissue seems to be a feedback mechanism.

Elevated cholesterol reduces acetylsalicylic acid-mediated platelet acetylation.

We describe the role of plasma and platelet cholesterol content in the ability of acetylsalicylic acid (ASA) to acetylate platelet proteins and inhibit platelet function. Platelet susceptibility to ASA was monitored in subjects differing in plasma total cholesterol and in suspensions of cholesterol-enriched or cholesterol-depleted platelets. Platelets from subjects with higher plasma cholesterol (>6 mmol/l) showed reduced platelet sensitivity to ASA (inhibition of platelet aggregation and thromboxane generation by 60% and 68% in 'lower-' vs. 32% and 56% in 'higher-cholesterol' donors; n=13 in each group; p=0.056 and p<0.04, respectively). [Acetyl-1-(14)C] incorporation to platelet proteins in subjects with higher plasma cholesterol was significantly reduced (11.0 vs. 14.6 nmol/g protein, p<0.0001) and correlated significantly with blood total cholesterolemia (R(K)=-0.430, p<0.003) and LDL-cholesterol (R(K)=-0.349, p<0.012), but not with platelet cholesterol content. In conclusion, elevated plasma cholesterol is an important determinant of ASA-induced acetylation of platelets and platelet diminished sensitivity to ASA. The molecular basis of such an association remains obscure, notwithstanding it may constitute a link between sub-optimal platelet response to aspirin and lipid metabolic disorders.

Polymorphism of selected enzymes involved in detoxification and biotransformation in relation to lung cancer.

Available data indicate that there are significant differences in individual susceptibility to lung cancer within the human population. It is believed to be underlie by inherited genetic predispositions related to the genetic polymorphism of several enzymes involved in the detoxification and xenobiotic metabolism. In this review, we collect and discuss the evidence reported up to date on the association between lung cancer and genetic polymorphism of cytochromes P450, N-acetyltransferase, glutathione S-transferases, microsomal epoxide hydrolase, NAD(P)H:quinone oxidoreductase, myeloperoxidase and glutathione peroxidase. All these genes might appear to be candidates for lung cancer susceptibility genes, nevertheless, the present state of the art still offers only a limited explanation of the link between such polymorphisms and increased risk of lung cancer.