A study of changes in protein expression in the membranes of cells undergoing apoptosis

This study aims to investigate the novel expression of proteins at the surface of cells during apoptosis. HeLa, MCF-7, and HL60 cells were induced to undergo apoptosis by the addition of 5mM 6-DMAP, 15 nM okadaic acid, and 2 jiM colchicine respectively. After 24 h, up to 50 % of the cell population appeared to be apoptotic and cell membrane preparations from both normal and apoptotic cells were carried out. The detection of novel proteins was approached by two different techniques: (i) subtractive immunization of mice for the generation of mAbs; and (ii) analysis of the whole protein profile from normal and apoptotic cells by 2D-PAGE. ELISA-tests and flow cytometric analysis showed that only a small number of mAbs had been produced against apoptotic antigens from MCF-7 cells but not from HeLa or HL60 cells. However, silverstained 2D-gels showed several proteins from all three cell types examined that were detectable in the apoptotic cells but not in the corresponding normal cells.