CHARACTERIZATION OF THE PLATELET-AGGREGATING ACTIVITY OF TUMOR-CELLS

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  • 1 January 1980
    • journal article
    • research article
    • Vol. 40  (4) , 1217-1222
Abstract
Two lines of mouse tumor cells were capable of aggregating mouse and rabbit platelets in vitro. This process required higher Mg2+ concentrations than were needed by other commonly used platelet-aggregating agents. Platelet-aggregating activity was also found in tumor cell membrane fragments. This membrane-bound platelet-aggregating material contained protein, lipid and carbohydrate moieties. The presence of all 3 appeared to be essential for stimulating platelet aggregation. Destruction of any component abolished its activity: protein by trypsin; lipid by phospholipase A2 and nonionic detergents; and sialic acid by neuraminidase. Platelet aggregation induced by tumor cell membrane fragments was associated with a secretory release reaction. In this process, growth-promoting activity for tumor cells was also released from platelets. The importance of platelets in establishing tumor metastases was underlined.