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A New evaluation of combined antitumor effects of natural and synthetic nuclear retinoid receptor ligands in human breast carcinoma cells
Strouhalová, Dana ; Laštovičková, Markéta ; Bobál, P. ; Macejová, D. ; Mosná, B. ; Brtko, J. ; Bobálová, Janette
This work represents the study of the effects of biologically active ligands of nuclear retinoid X receptors, triorganotin compounds, on proteomic profile of MDA-MB-231 cells. We focused primarily on tributyl/phenyltin derivatives that suggest the combined antitumor effect when they are used with natural nuclear retinoid receptor ligand all-trans retinoic acid (ATRA). Proteomic strategies connected to PDQuest evaluation were applied in this study. Some specific proteins with tumor process association were chosen for more detail study. Our findings indicate that selected triorganotins derivatives resulted to significantly reduced level of studied proteins belonging to metabolic pathway or to other cellular processes as apoptosis or epithelial–mesenchymal transition. In the case of vimentin, the key protein of EMT process, the silencing was set up by triorganotin compounds and significantly enhanced by combination with ATRA. This additive effect on downregulation can result from the potential engagement of RXR/RAR heterodimer, considering co-addition of both partner ligands of mentioned heterodimer to the treatment.
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Optimization of N-glycopeptides analysis methods and their preliminary application to barley proteins study
Benkovská, Dagmar ; Flodrová, Dana ; Bobálová, Janette ; Laštovičková, Markéta
N-glycosylation is the most frequently studied plant protein post-translational modification. The analysis of Nglycopeptides after protein proteolytic digestion offers information about the structure of both oligosaccharide and peptide moiety. However, this method has so far been less commonly used. Since glycopeptides hardly ionize during MS analysis in the presence of non-glycosylated peptides, they need to be separated from the complex peptide mixture. In this study, the glycopeptides enrichment, purification and analysis methods were successfully optimized on two standard N-glycoproteins. Concanavalin A (ConA) lectin tips were used for glycopeptide capturing, and obtained fractions were purified on carbon tips and analyzed using MALDI-TOF mass spectrometry. The differences in the CID fragmentation of certain types of glycopeptides were found. This technique was then applied to glycopeptide analysis of barley grain and malt proteins. Several barley glycopeptides were found, however, their identification was very difficult. More proteins separation techniques will be required before this enrichment procedure in further studies.
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