N-ethylmaleimide-enhanced phosphatidylserine externalization of human pancreatic cancer cells and immediate phosphatidylserine-mediated phagocytosis by macrophages

The purpose of this study was to examine whether N-ethylmaleimide (NEM) can enhance phosphatidylserine (PS) externalization on the outer surface of ca ncer cells, and PS-externalized cancer cells can be phagocytosed immediatel y by macrophages. NEM could externalize PS of cancer cells in concentration - and time-dependent manners, When treated with 5 mid NEM for 1 h, 80% of t he carcinoma cells externalized their PS. In phagocytosis assay, these cell s were engulfed immediately by macrophages before undergoing apoptosis. The se results suggest that NEM can immediately externalize PS of cancel cells, leading to their recognition and phagocytosis by macrophages before underg oing apoptosis morphologically.