Physical Activity and DNA Methylation in Humans.

Physical activity is a strong stimulus influencing the overall physiology of the human body. Exercises lead to biochemical changes in various tissues and exert an impact on gene expression. Exercise-induced changes in gene expression may be mediated by epigenetic modifications, which rearrange the chromatin structure and therefore modulate its accessibility for transcription factors. One of such epigenetic mark is DNA methylation that involves an attachment of a methyl group to the fifth carbon of cytosine residue present in CG dinucleotides (CpG). DNA methylation is catalyzed by a family of DNA methyltransferases. This reversible DNA modification results in the recruitment of proteins containing methyl binding domain and further transcriptional co-repressors leading to the silencing of gene expression. The accumulation of CpG dinucleotides, referred as CpG islands, occurs at the promoter regions in a great majority of human genes. Therefore, changes in DNA methylation profile affect the transcription of multiple genes. A growing body of evidence indicates that exercise training modulates DNA methylation in muscles and adipose tissue. Some of these epigenetic markers were associated with a reduced risk of chronic diseases. This review summarizes the current knowledge about the influence of physical activity on the DNA methylation status in humans.

17ß-Hydroxysteroid Dehydrogenase Type 1 Inhibition: A Potential Treatment Option for Non-Small Cell Lung Cancer.

In the face of the clinical challenge posed by non-small cell lung cancer (NSCLC), the present need for new therapeutic approaches is genuine. Up to now, no proof existed that 17ß-hydroxysteroid dehydrogenase type 1 (17ß-HSD1) is a viable target for treating this disease. Synthesis of a rationally designed library of 2,5-disubstituted furan derivatives followed by biological screening led to the discovery of 17ß-HSD1 inhibitor 1, capable of fully inhibiting human NSCLC Calu-1 cell proliferation. Its pharmacological profile renders it eligible for further in vivo studies. The very high selectivity of 1 over 17ß-HSD2 was investigated, revealing a rational approach for the design of selective inhibitors. 17ß-HSD1 and 1 hold promise in fighting NSCLC.

Circulating vascular endothelial growth factor receptor 2 levels and their association with lipid abnormalities in patients on hemodialysis.

The aim of the present study was to examine the association between the levels of circulating vascular endothelial growth factor receptor (VEGFR)2 levels, serum lipid composition and plasma receptor for advanced glycation end-products (RAGE) expression in patients undergoing hemodialysis (HD). A total of 50 patients on HD (27 men and 23 women; median age, 66 years; age range 28-88 years; HD mean time, 29.0, 3.9-157.0 months) were enrolled. Age-matched healthy subjects (n=26) were used as the control group. Plasma VEGFR2 and RAGE levels were determined using ELISA. Dyslipidemia (D) in patients on HD was diagnosed according to the Kidney Disease Outcomes Quality Initiative Clinical Practice Guidelines for Managing Dyslipidemias in Chronic Kidney Disease. Circulating VEGFR2, RAGE and serum lipids were compared between dyslipidemic and non-dyslipidemic patients on HD and controls. In patients on HD, the plasma VEGFR2 levels were lower compared with those in the healthy population. D was associated with high plasma VEGFR2 levels. The triglyceride/HDL-cholesterol ratio was strongly associated with plasma VEGFR2 levels. The plasma VEGFR2 concentration was associated with circulating RAGE levels. Therefore, circulating VEGFR2 levels may be partly associated with lipid abnormalities and plasma RAGE levels in patients receiving HD.

Altered expression of 17­ß­hydroxysteroid dehydrogenase type 2 and its prognostic significance in non­small cell lung cancer.

Numerous studies have reported that oestrogens may contribute to the development of non­small cell lung cancer (NSCLC). Although different steroidogenic enzymes have been detected in the lung, the precise mechanism leading to an exaggerated accumulation of active oestrogens in NSCLC remains unexplained. 17­ß­Hydroxysteroid dehydrogenase type 2 (HSD17B2) is an enzyme involved in oestrogen and androgen inactivation by converting 17­ß­oestradiol into oestrone, and testosterone into 4­androstenedione. Therefore, the enzyme serves an important role in regulation of the intracellular availability of active sex steroids. This study aimed to determine the expression levels of HSD17B2 in lung cancer (LC) and adjacent histopathologically unchanged tissues obtained from 161 patients with NSCLC, and to analyse the association of HSD17B2 with clinicopathological features. For that purpose, reverse transcription­quantitative PCR, western blotting and immunohistochemistry were conducted. The results revealed that the mRNA and protein expression levels of HSD17B2 were significantly decreased in LC tissues compared with matched controls (P<10­6). Conversely, strong cytoplasmic staining of HSD17B2 was detected in the unchanged respiratory epithelium and in glandular cells. Notably, a strong association was detected between reduced HSD17B2 expression and advanced tumour stage, grade and size. Furthermore, it was revealed that HSD17B2 may have potential prognostic significance in NSCLC. A log­rank test revealed the benefit of high HSD17B2 protein expression for the overall survival (OS) of patients (P=0.0017), and multivariate analysis confirmed this finding (hazard ratio=0.21; 95% confidence interval=0.07­0.63; P=0.0043). Stratified analysis in the Kaplan­Meier Plotter database indicated that patients with higher HSD17B2 expression presented better OS and post­progression survival. This beneficial effect was particularly evident in patients with adenocarcinoma and during the early stages of NSCLC. Decreased expression of HSD17B2 appears to be a frequent feature in NSCLC. Retrospective analysis suggests that the HSD17B2 mRNA and protein status might be independent prognostic factors in NSCLC and should be further investigated.

The influence of conjugated linoleic acid on the expression of peroxisome proliferator-activated receptor-γ and selected apoptotic genes in non-small cell lung cancer.

In recent years, peroxisome proliferator-activated receptor-γ (PPARγ) has been intensively studied. Because its activation is often associated with changes in the expression level of various apoptotic genes, many studies have emphasized the role of PPARγ as an important anticancer agent. However, in different types of cancer, different genes are influenced by PPARγ action. Previous studies showed that conjugated linoleic acid (CLA) was able to induce apoptosis, upregulate PPARG gene expression and activate PPARγ protein in certain human cancer cell lines. Moreover, some PPARγ agonists inhibited the growth of human lung cancer cells through the induction of apoptosis. Nevertheless, the impact of CLA on PPARγ mRNA and protein levels in non-small cell lung cancer (NSCLC) cell lines has not been investigated thus far. Therefore, in our study, we analysed the influence of the c9,t11 linoleic acid isomer on the expression of PPARG and other genes involved in the apoptotic response (BCL-2, BAX, and CDKN1A) in two NSCLC cell lines of different histological origin (A549 and Calu-1) and in normal human bronchial epithelial Beas-2B cells. Cells were treated with several doses of c9,t11 CLA, followed by RNA and protein isolation, cDNA synthesis, real-time quantitative PCR (RT-qPCR) and Western blot analysis. We showed that the investigated CLA isomer was able to enhance the expression of PPARγ in the examined cell lines and alter the mRNA and protein levels of genes involved in apoptosis. Fluorescent staining and MMT assay revealed the antiproliferative potential of CLA as well as its ability to activate pathways that lead to cell death.

Decreased expression of connective tissue growth factor in non-small cell lung cancer is associated with clinicopathological variables and can be restored by epigenetic modifiers.

PURPOSE: Recent studies indicated undisputed contribution of connective tissue growth factor (CTGF) in the development of many cancers, including non-small cell lung cancer (NSCLC). However, the functional role and regulation of CTGF expression during tumorigenesis remain elusive. Our goal was to determine CTGF transcript and protein levels in tumoral and matched control tissues from 98 NSCLC patients, to correlate the results with clinicopathological features and to investigate whether the CTGF expression can be epigenetically regulated in NSCLC. METHODS: We used quantitative PCR, Western blotting and immunohistochemistry to evaluate CTGF expression in lung cancerous and histopathologically unchanged tissues. We tested the impact of 5-Aza-2'-deoxycytidine (5-dAzaC) and trichostatin A (TSA) on CTGF transcript and protein levels in NSCLC cells (A549, Calu-1). DNA methylation status of the CTGF regulatory region was evaluated by bisulfite sequencing. The influence of 5-dAzaC and TSA on NSCLC cells viability and proliferation was monitored by the trypan blue assay. RESULTS: We found significantly decreased levels of CTGF mRNA and protein (both p < 0.0000001) in cancerous tissues of NSCLC patients. Down-regulation of CTGF occurred regardless of gender in all histological subtypes of NSCLC. Moreover, we showed that 5-dAzaC and TSA were able to restore CTGF mRNA and protein contents in NSCLC cells. However, no methylation within CTGF regulatory region was detected. Both compounds significantly reduced NSCLC cells proliferation. CONCLUSIONS: Decreased expression of CTGF is a common feature in NSCLC; however, it can be restored by the chromatin-modifying agents such as 5-dAzaC or TSA and consequently restrain cancer development.

Increased expression of 17-beta-hydroxysteroid dehydrogenase type 1 in non-small cell lung cancer.

OBJECTIVES: Recent studies indicated that estrogens may influence the development of non-small cell lung cancer (NSCLC). The 17-beta-hydroxysteroid dehydrogenase type 1 (HSD17B1) catalyzes the reduction of estrone (E1) to the highly potent E2. Although the significance of aromatase in an intratumoral E2 production in NSCLC is well established, the role of HSD17B1 remains largely unknown. Therefore, we investigated the expression of HSD17B1 in lung cancerous and corresponding histopathologically unchanged tissues from NSCLC patients and the association between HSD17B1 expression and clinicopathological features. Than, we examined the biological significance of HSD17B1 in NSCLC cells in vitro. We tested the impact of 5-Aza-2'-deoxycytidine (5-dAzaC) on HSD17B1 expression and activity. MATERIALS AND METHODS: We used Real Time quantitative PCR (RT-qPCR), Western blotting and immunohistochemistry to evaluate HSD17B1 expression in tissues obtained from 48 patients with NSCLC. The methylation status of the promoter region of HSD17B1 in A549 and Calu-1 cells was evaluated by bisulfite sequencing. We investigated the effect of 5-dAzaC on HSD17B1 transcript levels (by RT-qPCR) and on HSD17B1 enzyme activity by measuring the conversion of E1 to E2. The xCELLigence System was used for monitoring of cell proliferation. RESULTS: We found a substantial increase of HSD17B1 mRNA and protein amount in NSCLC tissues compared with histopathologically unchanged tissues in the group of male patients. An overexpression of HSD17B1 was associated with squamous cell carcinoma and with lung cancer stage 3A. We showed that 5-dAzaC induces DNA demethylation of HSD17B1 promoter, leading to increased HSD17B1 mRNA levels and protein activity in NSCLC cells. It resulted in enhanced E2 production in both cell lines and supported the proliferation of Calu-1 cells but not A549 cells. CONCLUSION: Increased expression of HSD17B1 in NSCLC may contribute to an elevated intratissue level of E2 and consequently may support the development and spread of cancer.

Exosomes in Plasma of Patients with Ovarian Carcinoma: Potential Biomarkers of Tumor Progression and Response to Therapy.

BACKGROUND: In patients with Ovarian Cancer (OvCa) exosomes released by tumor cells are present in the plasma and could be involved in tumor progression. This study examines the association between the exosome presence/protein content in plasma of OvCa patients and disease outcome, response to standard therapy and/or tumorresistance to therapies in patients studied at diagnosis and also serially during and after therapy. DESIGN AND METHODS: Exosomes were purified from OvCa patients' plasma (n=22), patients with benign tumors (n=10) or (n=10) healthy controls (NC) using ultracentrifugation. Exosomes were visualized by scanning electron microscopy. Their protein content was measured. The presence of MAGE 3/6 and TGF-ß1 in exosomes was evaluated in Western blots. RESULTS: The OvCa patients' plasma contained higher levels of exosomal proteins (p<0.05) compared to those isolated from plasma of patients with benign tumors or NC. Exosomes isolated from OvCa patients's plasma carried TGF-ß1 and MAGE3/6, which distinguished OvCa patients from those with benign tumors and NC. High protein levels of exosomes were seen in newly diagnosed patients; however in advanced stages of OvCa patients the protein content of isolated exosomes was significantly higher than that of early stages. The exosome levels variably changed during/after chemotherapy, and correlations between the changes in exosomal protein levels and clinical data suggested that the protein content of exosomes might be useful in predicting responses to therapy and prognosis in OvCa patients. CONCLUSION: Analysis of plasma exosomes levels offers a novel approach to diagnosis and monitoring response to therapies in OvCa patients.

Conversion of estrone to 17-beta-estradiol in human non-small-cell lung cancer cells in vitro.

It has recently been suggested that, in addition to genetic and environmental factors and tobacco exposure, estrogens also may be an independent risk factor in the development of lung cancer. Therefore, we evaluated the transcript and protein levels of 17-beta-hydroxysteroid-dehydrogenase type 1 (HSD17B1), and the conversion of estrone (E1) to 17-beta-estradiol (E2) in human non-small cell lung cancer (NSCLC) Calu-6, Calu-1 and A549 cells. In our work, we established the presence of HSD17B1 transcripts and proteins in all examined NSCLC cells. Moreover, we demonstrated that human NSCLC Calu-6, Calu-1 and A549 cells are able to convert weak estrogen E1 to highly potent E2 in vitro. Our results indicate that NSCLC cells are able to produce E2 from E1.