Consequences of the natural retinoid/retinoid X receptor ligands action in human breast cancer MDA-MB-231 cell line: Focus on functional proteomics.

The main intention of this study was the investigation of impact of natural biologically active ligands of nuclear retinoid/retinoid X receptors (all-trans and 9-cis retinoic acid) on proteomic pattern in human estrogen receptor negative breast cancer cell line MDA-MB-231. For this purpose, proteomic strategies based on bottom-up method were applied. The total cell proteins were extracted utilizing a commercially Radio-Immunoprecipitation Assay (RIPA) buffer and separated on 2D sodium dodecyl sulfate polyacrylamide gel electrophoresis (2D SDS-PAGE). The proteins were subsequently digested in-gel by trypsin and their characterization was achieved by MALDI-TOF/TOF. By employing PDQuest™ software, we identified more than 50 proteins affected by retinoic acid isomers. For more information, 9 proteins which are associated with tumor process were selected. We determined that derivatives of retinoic acid led to significantly reduced level of proteins belonging to metabolic pathway (e.g. glyceraldehyde-3-phosphate dehydrogenase or pyruvate kinase 2) or to other cellular processes as apoptosis, regulation of transcription process or epithelial-mesenchymal transition (e.g. annexins, nucleoside diphosphate kinase B, vimentin). On the other hand all-trans retinoic acid treatment indicates up-regulated effect for heterogeneous nuclear ribonucleoprotein A2/B1.

Proteomic analysis of changes in the protein composition of MCF-7 human breast cancer cells induced by all-trans retinoic acid, 9-cis retinoic acid, and their combination.

Retinoic acid (all-trans and 9-cis) isomers represent important therapeutic agents for many types of cancers, including human breast cancer. Changes in protein composition of the MCF-7 human breast cancer cells were induced by all-trans retinoic acid, 9-cis retinoic acid, and their combination and subsequently proteomic strategies based on bottom-up method were applied. Proposed approach was used for the analysis of proteins extracted from MCF-7 human breast cancer cell line utilizing a commercially manufactured kit RIPA and separated on two dimensional (2D) sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) after treatment with both retinoic acid isomers. We found significant differences in occurrence of proteins probably affecting the cell migration process in tumour cells. Heat shock protein 27, ribonucleoprotein SmD3, and cofilin-1 were significantly upregulated after treatment with combination of individual retinoic acid isomers. On the other hand, AP-5 complex subunit beta-1 shows the different response. Thus, the results might help to find the answer to important medical questions on (i) the identification of signaling pathways affected by retinoic acid isomers or (ii) how the observed proteomic pattern might reflect the effectiveness of retinoic acids treatment.

Effects of retinoic acid isomers on proteomic pattern in human breast cancer MCF-7 cell line.

Retinoids, acting through their cognate nuclear receptors, are crucial transcriptional regulators of many cellular processes such as differentiation, development, apoptosis, carbohydrate and lipid metabolism, homeostasis, etc. The aim of this study was the exploration of molecular mechanisms in relation to therapy of human breast cancer. One of the efficient strategies is identification of biomarkers as important tools in early cancer diagnosis and advisable treatment. Retinoids have been regarded as important therapeutic agents for many types of cancers, including human breast cancer. The effects of all-trans retinoic acid and 9-cis retinoic acid or their combination on proteomic pattern in human MCF-7 breast cancer line were investigated. The total cell proteins were extracted utilizing a commercially Radio-Immunoprecipitation Assay (RIPA) buffer and separated on 1D sodium dodecyl sulfate polyacrylamide gel electrophoresis (1D SDS-PAGE). The proteins were subsequently digested in-gel by trypsin and identified by matrix assisted laser desorption ionization technique with time of flight mass analyzer (MALDI-TOF/TOF). Our data offer novel information on the proteomic pattern of proteins evaluated after treatment of MCF-7 cells with retinoic acid isomers.

An efficient proteomic approach to analyze agriculture crop biomass.

While a plant cell wall is formed by a complex of various components, including polysaccharides and structural proteins, its composition and representation may vary during cell growth. Currently, plant research targets the proteins participating in wall loosening. Multiple classes of enzymes, including various hemicellulases and cellulases, are required for plant material degradation to achieve the maximum decomposition. Identifying the set of proteins involved in the breakdown of cell-wall polymers is important to understand plant material conversion into suitable products. The objective of this study was to describe a method which can be used to carry out proteomics analysis of complex plant samples and identify enzymes degrading biomass. For this purpose we used proteomic techniques including gel electrophoresis, high pressure liquid chromatography combinated with mass spectrometry followed by data evaluation using databases searching. Results show that more than 50 % of these activities correspond to enzymes with proteolytic function. This study was focused primarily on enzymes able to breakdown the lignocellulosic and hemicellulosic parts that are very important for the material conversion into required products of degradation.