Variation of selected genotoxic and epigenetic markers due to therapeutic exposure to PAHs and ultraviolet radiation.

BACKGROUND: Goeckerman therapy (GT) of psoriasis involves dermal application of crude coal tar containing polycyclic aromatic hydrocarbons (PAHs) and exposure to ultraviolet radiation (UVR). Little is known about GT influence on DNA epigenetics. OBJECTIVE: The study aim was to discover epigenetic mechanisms altered by the exposure related to the GT of psoriasis. METHODS: Observed group of patients with plaque psoriasis (n = 23) was treated by GT with 3 % CCT. Before and after GT, we analyzed the levels of benzo[a]pyrene-7,8-diol-9,10-epoxide-DNA adducts (BPDE-DNA), p53 protein in serum, 5-methylcytosine (5-mC, global DNA methylation), and methylation in selected CpG sites of p53 gene. RESULTS: We found a significant increase in the levels of BPDE-DNA (p < 0.01) and serum levels of p53 protein (p < 0.01) after GT, and an insignificant decrease in the percentage of 5-mC in peripheral blood DNA. Methylation of p53 CpG sites was affected neither by psoriasis nor by GT. The study confirmed good effectiveness of GT (significantly reduced psoriasis area and severity index; p < 0.001). CONCLUSION: Our findings indicate that there is a significantly increased genotoxic hazard related to the exposure of PAHs and UV radiation after GT of psoriasis. However, global DNA methylation and p53 gene methylation evade the effect of GT, as they remained unchanged (Tab. 4, Fig. 3, Ref. 50).

Deregulation of Selected MicroRNAs in Sinonasal Squamous Cell Carcinoma: Searching for Potential Prognostic Biomarkers.

Sinonasal carcinomas are head and neck tumours arising from the nasal cavity and paranasal sinuses characterized by unfavourable outcome, difficult treatment, diagnosis and prognosis. MicroRNAs are key molecules in the regulation of development and progression of cancer and their expression profiles could be used as prognostic biomarkers, to predict the patients' survival and response to treatment. In this study, we used quantitative real­time PCR with TaqMan® Advanced miRNA Assays to investigate the relative expression values of selected micro- RNAs in a unique set of formalin-fixed paraffin-embedded tissue samples obtained from 46 patients with sinonasal squamous cell carcinoma. Our results showed statistically significant up-regulation of three mature microRNAs: miR-9-5p (fold change: 6.80), miR-9-3p (fold change: 3.07) and let-7d (fold change: 3.93) in sinonasal carcinoma patients. Kaplan-Meier survival analysis and logrank test identified association between higher expression of miR-9-5p and longer survival of the patients (P = 0.0264). Lower expression of let-7d was detected in the patients with impaired survival, and higher expression of miR-137 was linked to shorter survival of the patients. We also identified several correlations between expression of the studied microRNAs and recorded clinicopathological data. Higher expression of miR-137 and lower expression of let-7d correlated with local recurrence (P = 0.045 and P = 0.025); lower expression of miR-9-5p and higher expression of miR-155-5p correlated with regional recurrence (P = 0.045 and P = 0.036). Higher expression of miR-9-3p correlated with occupational risk (P = 0.031), presence of vascular invasion (P = 0.013) and perineural invasion (P = 0.031). Higher expression of miR-155-5p was present in the samples originating from maxillary sinus (P = 0.011), cN1-3 classified tumours (P = 0.009) and G2-3 classified tumours (P = 0.017). In conclusion, our study supports the hypothesis of future prospect to use expression of miRNAs as prognostic biomarkers of squamous cell sinonasal carcinoma. In particular, miR-9-5p and miR-9-3p seem to be important members of the sinonasal cancer pathogenesis.

Analysis of DNA methylation and microRNA expression in NUT (nuclear protein in testis) midline carcinoma of the sinonasal tract: a clinicopathological, immunohistochemical and molecular genetic study.

The aim of this study was a detailed clinicopathological investigation of sinonasal NUT midline carcinoma (NMC), including analysis of DNA methylation and microRNA (miRNA) expression. Three (5%) cases of NMC were detected among 56 sinonasal carcinomas using immunohistochemical screening and confirmed by fluorescence in situ hybridization. The series comprised 2 males and 1 female, aged 46, 60, and 65 years. Two tumors arose in the nasal cavity and one in the maxillary sinus. The neoplasms were staged pT1, pT3, and pT4a (all cN0M0). All patients were treated by radical resection with adjuvant radiotherapy. Two patients died 3 and 8 months after operation, but one patient (pT1 stage; R0 resection) experienced no evidence of disease at 108 months. Microscopically, all tumors consisted of infiltrating nests of polygonal cells with vesicular nuclei, prominent nucleoli and basophilic cytoplasm. Abrupt keratinization was present in only one case. Immunohistochemically, there was a diffuse expression of cytokeratin (CK) cocktail, CK7, p40, p63, and SMARCB1/INI1. All NMCs tested negative for EBV and HPV infection. Two NMCs showed methylation of RASSF1 gene. All other genes (APC, ATM, BRCA1, BRCA2, CADM1, CASP8, CD44, CDH13, CDKN1B, CDKN2A, CDKN2B, CHFR, DAPK1, ESR1, FHIT, GSTP1, HIC1, KLLN, MLH1a, MLH1b, RARB, TIMP3, and VHL) were unmethylated. All NMCs showed upregulation of miR-9 and downregulation of miR-99a and miR-145 and two cases featured also upregulation of miR-21, miR-143, and miR-484. In summary, we described three cases of sinonasal NMCs with novel findings on DNA methylation and miRNA expression, which might be important for new therapeutic strategies in the future.

Importance of Tumour Suppressor Gene Methylation in Sinonasal Carcinomas.

Epigenetic changes are considered to be a frequent event during tumour development. Hypermethylation of promoter CpG islands represents an alternative mechanism for inactivation of tumour suppressor genes, DNA repair genes, cell cycle regulators and transcription factors. The aim of this study was to investigate promoter methylation of specific genes in samples of sinonasal carcinoma by comparison with normal sinonasal tissue. To search for epigenetic events we used methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) to compare the methylation status of 64 tissue samples of sinonasal carcinomas with 19 control samples. We also compared the human papilloma virus (HPV) status with DNA methylation. Using a 20% cut-off for methylation, we observed significantly higher methylation in RASSF1, CDH13, ESR1 and TP73 genes in the sinonasal cancer group compared with the control group. HPV positivity was found in 15/64 (23.4 %) of all samples in the carcinoma group and in no sample in the control group. No correlation was found between DNA methylation and HPV status. In conclusion, our study showed that there are significant differences in promoter methylation in the RASSF1, ESR 1, TP73 and CDH13 genes between sinonasal carcinoma and normal sinonasal tissue, suggesting the importance of epigenetic changes in these genes in carcinogenesis of the sinonasal area. These findings could be used as prognostic factors and may have implications for future individualised therapies based on epigenetic changes.

Promoter methylation of GATA4, WIF1, NTRK1 and other selected tumour suppressor genes in ovarian cancer.

Ovarian cancer is the leading cause of death from gynaecologic tumours, but the molecular and especially epigenetic events underlying the transformation are poorly understood. Various methylation changes have been identified and show promise as potential cancer biomarkers. The aim of this study was to investigate promoter methylation of selected tumour suppressor genes in ovarian cancer by comparison with normal ovarian tissue. To search for epigenetic events we used methylation-specific multiplex ligation-dependent probe amplification to compare the methylation status of 44 tissue samples of ovarian cancer with 30 control samples. Using a 20% cut-off for methylation, we observed significantly higher methylation in genes NTKR1, GATA4 and WIF1 in the ovarian cancer group compared with the control group. These findings could potentially be used in screening of ovarian cancer, and may have implications for future chemotherapy based on epigenetic changes.

Hypermethylation of RAD51L3 and XRCC2 genes to predict late toxicity in chemoradiotherapy-treated cervical cancer patients.

Cervical cancer affects women worldwide, especially in developing countries. Approximately 500,000 cases of this disease are diagnosed per year. The method of choice in the treatment of advanced cervical cancers (in accordance with the International Federation of Gynecology and Obstetrics staging system (FIGO) starting from stage IIB) is combined radiotherapy with concomitant chemotherapy. This treatment provides good tumour control, but it carries a risk of late complications in the irradiated area in 10-15 % of cases. Methylation is one of the methods of epigenetic control, which has an important role in gene expression. Aberrant methylation of normal CpG islands in promoters of tumour suppressor genes such as RB, p53 or DNA reparation genes ATM, BRCA1,2, and RAD51 gene family causes silencing of their function and cell cycle deregulation, which is one of the efficient ways of neoplastic transformation. The significantly decreased expression of molecules involved in DNA response may cause facilitated radiosensitivity in predisposed individuals. We looked for the relationship between hypermethylation of 18 DNA reparation genes and late toxicity occurrence in cervical cancer patients treated by chemoradiotherapy using methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA). The cut-off value for the hypermethylation was set at 10 %. We confirmed significant association between promoter hypermethylation in the XRCC2 gene and occurrence of late grade III-IV toxicity in cervical cancer patients (P = 0.0357). This finding could be useful in the late toxicity prediction in radiotherapy-treated patients.

Methylation analysis of tumour suppressor genes in ovarian cancer using MS-MLPA.

Epigenetic changes are considered to be a frequent event during tumour development. Hypermethylation of promoter CpG islands represents an alternative mechanism for inactivation of tumour suppressor genes, DNA repair genes, cell cycle regulators and transcription factors. The aim of this study was to investigate promoter methylation of specific genes in ovarian cancer by comparison with normal ovarian tissue. To search for epigenetic events we used methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) to compare the methylation status of 69 tissue samples of ovarian cancer with 40 control samples. Using a 15% cut-off for methylation, we observed significantly higher methylation in genes MGMT, PAX5, CDH13, WT1, THBS1, GATA5 in the ovarian cancer group, while in the ESR1 gene we observed significantly higher methylation in the control group compared with the ovarian cancer group. These findings could potentially be used in screening of ovarian cancer and may have implications for future chemotherapy based on epigenetic changes.

[What is the prognostic importance of molecular genetic factors in endometrial carcinoma?]. / Jaký je prognostický význam molekulárne genetických faktoru u karcinomu endometria?

BACKGROUND: Evaluation of the importance of molecular genetic factors in endometrial carcinoma based on our review of available literature, and in the case of K- ras mutation based on our own data. The aim of the original part of our study was to compare the presence of K- ras mutation in early stages of endometroid carcinoma with normal endometrium and evaluate the role of the mutation in endometrial carcinogenesis. MATERIAL AND METHODS: Molecular bio-logical analysis was performed to detect K- ras mutation in samples of endometrial tissue obtained from women treated in the past at the Department of Obstetrics and Gynecology, University Hospital Hradec Kralove. The detection was made from DNA isolated from paraffin embedded sections using K- ras -StripAssay, ViennaLab Diagnostics GmbH. RESULTS: K- ras mutation was found in 7 out of 30 specimens of endometroid carcinoma in stage I (23%) and in 3 of 20 specimens of normal endometrium in the control group (15%). K- ras mutations were more frequent in IA stage and grade 1 of endometroid carcinoma. CONCLUSION: The importance of molecular genetic factors in endometrial carcinoma differs depending on the type of carcinoma. In more common type 1 endometroid cancer, published data are not as clear as in type 2 carcinoma, in which prevalence of alteration of p53 reaches 90%. Results of our study performed on local population of women support the theory about the possible role of K- ras mutation as an early event in the process of endometrial carcinogenesis in type 1 tumors.

The effect of ATM and ERK1/2 inhibition on mitoxantrone-induced cell death of leukaemic cells.

The relationship between signal pathways MEK1/2-ERK1/2 and ATM-p53 in the response to DNA damage is not well understood. The aim of our study was to investigate the effect of mitoxantrone and two protein kinase inhibitors - caffeine (inhibitor of ATM kinase) and U0126 (inhibitor of MEK1/2 kinase) - on MOLT-4 and Jurkat leukaemic cell lines. In this work we show that the inhibition of MEK1/2 is associated with an increased mortality of cells after mitoxantrone treatment. Inhibition of ATM by caffeine delayed mitoxantrone-induced cell death in MOLT-4 cells. Mitoxantrone itself induced cell-cycle arrest and accumulation of the cells in late S and G2/M phase. Inhibition of ATM, but not of MEK1/2, abrogated mitoxantrone-induced cell-cycle arrest. Inhibition of MEK1/2 did not change mitoxantroneinduced up-regulation of p53 and p21, but inhibition of ATM markedly decreased up-regulation of p53 and p21, and p53 phosphorylation on serine 15 and serine 392. It can be concluded that: 1) mitoxantrone- induced phosphorylation of p53 on serine 15 and serine 392 is ATM dependent and MEK1/2-ERK1/2 independent. 2) ATM inhibition by caffeine prevents G2 cell arrest and in p53-positive cells MOLT-4 delays the onset of mitoxantrone-induced cell death. 3) Inhibition of MEK1/2-ERK1/2 cascade potentiates the cytostatic effect of mitoxantrone regardless of the p53 status.

Roles of miR-31 and endothelin-1 in psoriasis vulgaris: pathophysiological functions and potential biomarkers.

Psoriatic lesions are characterized by hyperproliferation, aberrant differentiation of keratinocytes resistant to apoptosis and inflammation. miR-31 plays pro-proliferative, pro-differentiative and pro-inflammatory roles and modulates apoptosis in psoriatic keratinocytes. Endothelin-1 (ET-1) is produced by psoriatic keratinocytes and suppresses apoptosis. Inflammation increases the production of ET-1, which in turn leads to the chronic stimulation of keratinocyte proliferation. The aim of this study was to identify the putative link between two potential biomarkers (miR-31 and ET-1) in patients with psoriasis. The study design included experimental group (29 patients with psoriasis), and the control group (22 blood donors). The PASI score evaluated the state of the disease (median: 18.6; interquartile range 14.5-20.9). Both, the serum level of ET-1 and the whole blood level of miR-31 were significantly increased (p<0.001 and p<0.05, respectively) in patients compared to the controls. However, a significant negative relationship between ET-1 and miR-31 was observed (Spearman's rho=-037, p=0.05). It is possible that a negative feedback loop will be present between miR-31 and ET-1. Our results indicate that miR-31 and ET-1, potential biomarkers of the disease, play significant roles in the pathophysiology of psoriasis.

Methylation in the p53 promoter in epithelial ovarian cancer

OBJECTIVE: Ovarian cancer is a leading cause of death from gynecologic tumors, however, the molecular and especially epigenetic events underlying this transformation are poorly understood. Promoter methylation status of tumor suppressor genes may be associated with transcriptional silencing and tumor progression. It has been shown that methylation of CpG dinucleotides located in the promoter region of p53 is associated with low expression levels of this gene. The aim of this study was to investigate promoter methylation of p53 gene in ovarian cancer by comparison with normal ovarian tissue. METHODS: To search for promoter methylation of p53 gene we used methylation-specific PCR (MSP) to compare the methylation status of 66 tissue samples of ovarian cancer with 37 control samples. RESULTS: In our study methylation specific PCR revealed p53 promoter methylation in 34 of 66 (51.5 %) of specimens with ovarian cancer. CONCLUSION: These results indicate that methylation in p53 promoter region may play an important role in carcinogenesis of ovarian cancer and could potentially be used in screening of ovarian cancer, and may have implications for future chemotherapy based on epigenetic changes (AU)