Marcela Chmelarova

Oxidative Damage to Nucleic Acids and Benzo(a)pyrene-7,8-diol-9,10-epoxide-DNA Adducts and Chromosomal Aberration in Children with Psoriasis Repeatedly Exposed to Crude Coal Tar Ointment and UV Radiation

The paper presents a prospective cohort study. Observed group was formed of children with plaque psoriasis (n=19) treated by Goeckerman therapy (GT). The study describes adverse (side) effects associated with application of GT (combined exposure of 3% crude coal tar ointment and UV radiation). After GT we found significantly increased markers of oxidative stress (8-hydroxy-2′-deoxyguanosine, 8-hydroxyguanosine, and 8-hydroxyguanine), significantly increased levels of benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE) DNA adducts (BPDE-DNA), and significantly increased levels of total number of chromosomal aberrations in peripheral lymphocytes. We found significant relationship between (1) time of UV exposure and total number of aberrated cells and (2) daily topical application of 3% crude coal tar ointment (% of body surface) and level of BPDE-DNA adducts. The findings indicated increased hazard of oxidative stress and genotoxic effects related to the treatment. However, it must be noted that the oxidized guanine species and BPDE-DNA adducts also reflect individual variations in metabolic enzyme activity (different extent of bioactivation of benzo[a]pyrene to BPDE) and overall efficiency of DNA/RNA repair system. The study confirmed good effectiveness of the GT (significantly decreased PASI score).

Serum Level of Antibody against Benzo[a]pyrene-7,8-diol-9,10-epoxide-DNA Adducts in People Dermally Exposed to PAHs

Some specific antibodies indicate the presence of antigenic structures on DNA (DNA adducts) that can play an important role in the process of mutagenesis and/or carcinogenesis. They indicate the presence of increased genotoxic potential (hazard) prior to the formation of disease (primary prevention). The present study was focused on the serum level of benzo[a]pyrene 7,8-diol-9,10-epoxide-DNA adducts antibodies (anti-BPDE-DNA) in psoriatic patients (n = 55) dermally exposed to different levels of polycyclic aromatic hydrocarbons (PAHs). The general goal of the study was to contribute to better understanding of the value of the assumed biomarker (anti-BPDE-DNA) for evaluation of the organisms answer to genotoxic exposure to PAHs. Elevated level of exposure to PAHs resulted in the increased level of anti-BPDE-DNA. However, almost all levels of anti-BPDE-DNA ranged within the field of low values. Both variants of GT (CCT-3% and CCT-5%) induced higher expression of anti-BPDE-DNA in the group of nonsmokers. Significant relations between the level of anti-BPDE-DNA and PASI score, total duration of the therapy, or time of UVR exposure were not found. Further studies are needed to reduce interpretation uncertainty of this promising bioindicator.

Importance of promoter methylation of GATA4 gene in epithelial ovarian cancer

AIMS Ovarian cancer is the most lethal gynecological malignancy, with typically late diagnosis. Altered DNA methylation of tumor suppressor gene promoters probably plays a relevant role in ovarian carcinogenesis and frequently occurs as an early event in the development of different types of cancer including ovarian carcinoma. GATA4 methylation has been reported in a variety of human cancers. The aim of this study was to investigate promoter methylation of the GATA4 gene in ovarian cancer by comparison with that in normal ovarian tissue. METHODS To search for promoter methylation of the GATA4 gene we used MSP (methylation-specific PCR) to compare the methylation status in 67 tissue samples of ovarian cancer with that in 40 control samples. RESULTS In our study, methylation-specific PCR revealed GATA4 promoter methylation in 21 of 67 specimens with ovarian cancer (31.3%), and in none of the control ovarian tissue samples. CONCLUSION These results confirm that methylation in the GATA4 promoter region could play an important role in ovarian carcinogenesis, and show new loci which are highly methylated only in ovarian cancer samples and which are associated predominantly with the endometrioid type of ovarian carcinoma.

Next-Generation Sequencing Approach in Methylation Analysis of HNF1B and GATA4 Genes: Searching for Biomarkers in Ovarian Cancer

DNA methylation is well-known to be associated with ovarian cancer (OC) and has great potential to serve as a biomarker in monitoring response to therapy and for disease screening. The purpose of this study was to investigate methylation of HNF1B and GATA4 and correlate detected methylation with clinicopathological characteristic of OC patients. The study group consisted of 64 patients with OC and 35 control patients. To determine the most important sites of HNF1B and GATA4, we used next-generation sequencing. For further confirmation of detected methylation of selected regions, we used high-resolution melting analysis and methylation-specific real-time polymerase chain reaction (PCR). Selected regions of HNF1B and GATA4 were completely methylation free in all control samples, whereas methylation-positive pattern was observed in 32.8% (HNF1B) and 45.3% (GATA4) of OC samples. Evaluating both genes together, we were able to detect methylation in 65.6% of OC patients. We observed a statistically significant difference in HNF1B methylation between samples with different stages of OC. We also detected subtype specific methylation in GATA4 and a decrease of methylation in late stages of OC. The combination of unmethylated HNF1B and methylated GATA4 was associated with longer overall survival. In our study, we employed innovative approach of methylation analysis of HNF1B and GATA4 to search for possible epigenetic biomarkers. We confirmed the significance of the HNF1B and GATA4 hypermethylation with emphasis on the need of selecting the most relevant sites for analysis. We suggest selected CpGs to be further examined as a potential positive prognostic factor.

Deregulation of selected microRNAs in sinonasal carcinoma: Value of miR-21 as prognostic biomarker in sinonasal squamous cell carcinoma

Tumors occurring in the sinonasal area are characterized by unfavorable outcome due to difficult diagnosis, treatment, and prognosis of the disease corresponding with the anatomic complexity of the area.

Importance of Cadherins Methylation in Ovarian Cancer: a Next Generation Sequencing Approach

Epigenetic aberrations are well known to play an important role in carcinogenesis, and also have a great potential to serve as biomarkers in many types of cancers, including ovarian cancer in which sensitive and specific biomarkers and detection methods are critically needed. The aim of this study was to investigate methylation of cadherin genes CDH10, CDH13 and CDH18 in ovarian cancer tissue by comparison with control tissue. The study group consisted of 38 patients with ovarian cancer and 25 control patients. For detection of epigenetic events we used next generation sequencing, the most important data were confirmed using high-resolution melting analysis and real-time PCR. We observed significantly higher methylation in CDH13, sporadic methylation in CDH10 and loss of methylation in CDH18 in the ovarian cancer group compared with the control group. These observations suggest that changes in methylation of cadherin genes may be one of the major mechanisms associated with ovarian cancer progression. In addition, because of the high frequency of methylation of the CDH13 gene in the early stages of ovarian cancer, the analyzed CpG sites might be good targets for next study of potential ovarian cancer screening biomarkers.

Elevated DNA methylation in malignant tumors of the sinonasal tract and its association with patient survival

BACKGROUND Epigenetic modifications have been recognized as an important mechanism underlying carcinoma progression. DNA methylation plays an important role in cancer biology and represents potentially heritable changes in gene expression that do not involve DNA sequence. The aim of this study was to investigate promoter methylation of selected genes in sinonasal carcinoma by comparison with noncancerous sinonasal tissue. METHODS To search for epigenetic events (methylation in 25 tumor suppressor genes) we used MS-MLPA (Methylation-specific multiplex ligation-dependent probe amplification) to compare methylation status of 59 formalin fixed, paraffin embedded tissue samples of sinonasal carcinomas with 18 control samples. The most important changes in methylation were confirmed using MSP (Methylation specific PCR). Detected alterations in methylation were compared with clinicopathological characteristics. RESULTS Using a 20% cut-off for methylation (MS-MLPA), we found significantly higher methylation in GATA5 (P=0.0005), THSB1 (P=0.0002) and PAX5 (P=0.03) genes in the sinonasal cancer group compared to the control group. Methylation in five or more genes was associated with impaired overall survival (P=0.017). CONCLUSION These findings provide evidence that alterations in methylation profile may be one of the major mechanisms in sinonasal carcinogenesis. In addition, changes in methylation could potentially be used as prognostic factors of sinonasal carcinoma and may have implications for future individualized therapy based on epigenetic changes.

Genetic polymorphisms in biotransformation enzymes for benzo[a]pyrene and related levels of benzo[a]pyrene-7,8-diol-9,10-epoxide-DNA adducts in Goeckerman therapy

Goeckerman therapy (GT) for psoriasis combines the therapeutic effect of crude coal tar (CCT) and ultraviolet radiation (UVR). CCT contains polycyclic aromatic hydrocarbons, some of which can form DNA adducts that may induce mutations and contribute to carcinogenesis. The aim of our work was to evaluate the relationship between concentrations of benzo[a]pyrene-7,8-diol-9,10-epoxide-DNA adducts (BPDE-DNA adducts) and rs4646903 (CYP1A1 gene), rs1048943 (CYP1A1), rs1056836 (CYP1B1), rs1051740 (EPHX1), rs2234922 (EPHX1) and rs8175347 (UGT1A1) polymorphic sites, and GSTM1 null polymorphism in 46 patients with chronic stable plaque psoriasis who underwent GT. The level of BPDE-DNA adducts was determined using the OxiSelect BPDE-DNA Adduct ELISA Kit. Polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis (rs4646903, rs1048943, rs1051740, and rs2234922), fragment analysis (rs8175347), real-time PCR (rs1056836), and digital droplet PCR polymorphism (GSTM1) were used. CYP1B1*1/*1 wild-type subjects and CYP1B1*3/*1 heterozygotes for rs1056836 formed significantly higher amounts of BPDE-DNA adducts than CYP1B1*3/*3 homozygotes (p=0.031 and p=0.005, respectively). Regarding rs1051740, individuals with EPHX1*3/*1 heterozygosity revealed fewer adducts than EPHX1*1/*1 wild-type subjects (p=0.026). Our data suggest that CYP1B1/EPHX1 genotyping could help to predict the risk of DNA damage and to optimize doses of coal tar and UVR exposure in psoriatic patients in whom GT was applied.