A novel protein from lamprey immune body with selective cytocidal actions to tumor cells (TUM7P.925)

Abstract

Abstract We purified and identified a novel protein, derived from cells of immune body tissues in the adult lamprey, the protein has strong cytocidal activity against various human cells with a markedly divergent target specificity, recognizes and kills human breast adenocarcinoma MCF-7, human caucasian chronic myelogenous leukaemia k562 cancer cells as well as some classes of human tumor cells, and less cytotoxic to the normal tissue cells. The novel protein induced remarkable morphological alterations, cell blebbing, cytoskeletal alterations, mitochondrial and endoplasmic reticulum fragmentation. Then the plasma membrane permeability was increased immediately and most of the cytoplasmic proteins and organelle proteins released into medium from tumor cells after the protein treatment. The novel protein shows specific binding to cell membrane and requires the high content of phosphatidylserine for the effective cytolysis. To confirm the novel protein effect on tumor, tumor xenograft experiments were performed, these results confirm that the novel protein inhibit tumor growth in vivo. Taken together, these observations suggest the novel protein play a crucial role in tumor cells survival and growth.