Markéta Laštovičková

Study of quantitative changes of cereal allergenic proteins after food processing

BACKGROUND Within last few years, the occurrence of food allergens and corresponding food allergies has been increasing, therefore research into the individual allergens is required. In the present work, the effect of cereal processing on the amounts of allergenic proteins is studied by modern proteomic-based approaches. The most important wheat and barley allergens are low-molecular-weight (LMW) proteins. Therefore we investigated the relative quantitative changes of these proteins after food technological processing, namely wheat couscous production and barley malting. RESULTS A comparative study using mass spectrometry in connection with the technique of isobaric tag for relative and absolute quantification (iTRAQ) revealed that the amount of wheat allergenic LMW proteins decreased significantly during couscous production (approximately to 5-26% of their initial content in wheat flour). After barley malting, the amounts of the majority of LMW proteins decreased as well, although to a lesser extent than in the case of wheat/couscous. The level of two allergens even slightly increased. CONCLUSION Suggested proteomic strategy proved as universal and sensitive method for fast and reliable identification of various cereal allergens and monitoring of their quantitative changes during food processing. Such information is important for consumers who suffer from allergies.

A comparative study of protein patterns of human estrogen receptor positive (MCF-7) and negative (MDA-MB-231) breast cancer cell lines.

In the present study, we analyzed the cell lysates of human tumour cell lines representing two major clinically different types of breast cancer. Our main goal was to show the differences between them on proteomic level. Gel electrophoresis followed by MALDI-TOF MS analysis was used for proteins determination. Exactly 98 proteins were unequivocally identified and 60 of them were expressed differentially between MDA-MB-231 and MCF-7 cell lines. Among the proteins reported here, some well-known breast cancer markers (e.g., annexin A1, annexin A2 and vimentin) were identified in the MDA-MB-231 cell line and thus we were able to distinguish both cell lines sufficiently.

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.