Analysis of proteomic changes in human breast carcinoma MDA-MB-231 cells induced by tributyltin isothiocyanate, the biologically active ligand of nuclear retinoid X receptors


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Julius Brtko1,Dana Strouhalova2,Lucia Toporova1,Dana Macejova1,Pavel Bobal3,Jan Otevrel3,Janette Bobalova2
1Institute of Experimental Endocrinology, BMC, Slovak Academy of Sciences, Bratislava,2Institute of Analytical Chemistry of the CAS, v. v. i., Brno,3Department of Chemical Drugs, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences Brno, Brno

Abstract

Background

Nuclear retinoid receptors (RARs) and retinoid X receptors (RXRs), which act upon binding of retinoids and rexinoids, respectively, as ligand inducible transcription factors are known to inhibit carcinogenesis, suppress premalignant epithelial lesions, tumour growth and invasion in a variety of tissues. The aim of this study was to investigate the effect of all-trans retinoic acid (RAR ligand), without or with tributyltin isothiocyanate, a potent RXR ligand on tumour cell protein profile.

Method

The MDA-MB-231, the oestrogen receptor negative human breast cancer cell line was selected for the gel associated proteomic strategies based on bottom-up method. The total cell proteins were extracted utilizing a Radio-Immunoprecipitation Assay buffer and separated on 2D sodium dodecyl sulphate polyacrylamide gel electrophoresis. After protein separation, individual 2D gel maps were analyzed, identified by MALDI-TOF/TOF and processed using PDQuestTM software.

Results

We have identified at least thirty proteins affected by tributyltin isothiocyanate. Subsequently, specific proteins associated with tumour progression were selected. We have found that tributyltin isothiocyanate in combination with all-trans retinoic acid significantly reduced protein levels of vimentin, nucleoside diphosphate kinase and glyceraldehyde-3-phospate dehydrogenase, proteins linked to metabolic processes, epithelial-mesenchymal transition or apoptosis.

Conclusion

Our data on combined effect of all-trans retinoic acid and tributyltin isothiocyanate based on proteomic analysis provide new insights into a role of RXR/RAR heterodimer. The knowledge achieved from current study offers further opportunity to study triorganotins more intensively in order to enhance antitumor effect of natural or synthetic RARs ligands and also take advantage of the fact on direct activation of RXR by triorganotins. Supported by the Institutional RVO:68081715 support of the Institute of Analytical Chemistry of the CAS, v.v.i., SAV-18-16, APVV-15-0372, APVV-0160-11, VEGA 2/0171/17 grants and Internal Grant Agency of the University of Veterinary and Pharmaceutical Sciences Brno, grant No. 320/2018/FaF.