Slavomira Ondkova
Slovak Academy of Sciences
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Featured researches published by Slavomira Ondkova.
Molecular and Cellular Endocrinology | 2007
Zdenek Dvorak; Radim Vrzal; Jitka Ulrichová; Dana Macejova; Slavomira Ondkova; Julius Brtko
Cellular signaling by glucocorticoid receptor and aryl hydrocarbon receptor is restricted by microtubules interfering agents (MIAs). This leads to down-regulation of drug metabolizing enzymes and drug interactions. Here we investigated the effects of all-trans-retinoic acid (ATRA) and MIAs, i.e. colchicine, nocodazole and taxol on the regulation of retinoic acid receptor (RAR) genes in primary cultures of rat hepatocytes. ATRA (1microM) down-regulated RARalpha and RARgamma mRNAs (decrease 23% and 41%, respectively) whereas it up-regulated RARbeta mRNA (4.3-fold induction). All MIAs diminished the expression of RARs in dose-dependent manner; the potency of MIAs increased in order NOC<COL<TAX and the extent of inhibition increased in order RARalpha<RARgamma<RARbeta. The levels of RARalpha protein were decreased by both MIAs and ATRA. The effects of ATRA were reversed by proteasome inhibitor MG-132, implying ligand-dependent RARalpha degradation. In contrast, the effects of MIAs were proteasome-independent and decrease in RARalpha protein content was due to RARalpha gene down-regulation. We monitored transcriptional activity of RARalpha. For this purpose, we measured catalytic activity of trans-glutaminase-target gene of RARalpha. trans-Glutaminase activity was increased by ATRA (1.23-fold increase) and decreased by colchicine (decrease 51%). Co-treatment with proteasome inhibitor MG-132 partly reversed inhibitory effect of colchicine, and it further augmented the increase of trans-glutaminase activity by ATRA. We have also observed decrease of RARalpha protein level and inhibition of RARs mRNAs expression in HeLa cells by MIAs. In conclusion, our data indicate that microtubules play the role in regulation of RARs activity and expression. Our data are the first report on the effects of ATRA and MIAs on RARs regulation in quiescent cells.
Toxicology Letters | 2011
Dana Macejova; Slavomira Ondkova; Lucia Jakubikova; Alžbeta Mlynarčíková; Soňa Scsuková; Jan Liska; Julius Brtko
The effects of administration of vitamin D₃ and Seocalcitol on MNU-induced carcinogenesis of mammary gland in Sprague-Dawley rats have been investigated. Administration of both substances in a weekly dose of 7 μg/kg caused prolonged latency of mammary gland tumors. The latency of tumors was markedly prolonged for 30-40 days by Seocalcitol. Using PET analysis, reduction in [¹⁸F]2-fluoro-2-deoxy-d-glucose (FDG) uptake or tumor volume in tumors chemopreventively treated with vitamin D₃ were detected in MNU-induced tumors, vitamin D₃ reduced expression of 25-hydroxylase (25OHase) (p<0.01) and 24-hydroxylase (24OHase) (p<0.01) and Seocalcitol 24OHase. Positive regulation of 25OHase mRNA level after the treatment with vitamin D₃ was observed in liver, while in kidney, vitamin D₃ and Seocalcitol induced expression of 24OHase was significant. Our observations indicate a cross talk between respective pathways of VDR, RARs/RXRs, TRs and ERs in carcinogenesis process.
Biologia | 2011
Jan Liska; Slavomira Ondkova; Dana Macejova; Julius Brtko
The effects of retinoic acid analogue — phytol (precursor of retinoic X receptors ligand), TTNPB (retinoic acid receptor agonist) and seocalcitol (EB1089, analogue of vitamin D3) in mammary tumours of Sprague-Dawley rats induced with 1-methyl-1-nitrosourea (MNU) were investigated. Treatment with phytol, TTNPB and seocalcitol may have some protective and therapeutical effects on malignant processes. Treatment with these components in combination of TTNPB and phytol or seocalcitol and phytol inhibited progression of MNU-induced tumours of the rat mammary gland, and also induced decrease of tumour burden and volume in comparison with treated control group. Treatment of rats with the above compounds had no effect on malignity and invasiveness of carcinomas.
General Physiology and Biophysics | 2009
Dana Macejova; Slavomira Ondkova; Julius Brtko
General Physiology and Biophysics | 2006
Slavomira Ondkova; Dana Macejova; Julius Brtko
Endocrine Regulations | 2012
Jan Liska; Dana Macejova; Slavomira Ondkova; Julius Brtko
General and Comparative Endocrinology | 2010
Slavomira Ondkova; Jan Bakos; Dana Macejova; Daniela Jezova; Julius Brtko
General Physiology and Biophysics | 2009
Julius Brtko; Sejnová D; Slavomira Ondkova; Dana Macejova
General Physiology and Biophysics | 2007
Dana Macejova; Zdenek Dvorak; Vrzal R; Ulrichová J; Slavomira Ondkova; Julius Brtko
17th European Congress of Endocrinology | 2015
Dana Macejova; Slavomira Ondkova; Jan Liska; Julius Brtko