COX and LOX eicosanoids modulate platelet activation and procoagulation induced by two murine cancer cells

Involvement of arachidonic acid cyclooxygenase (COX) and lipoxygenase (LOX) metabolites in platelet aggregation and coagulation induced by two varieti es of cancer cells of murine transplantable tumors was studied. A lung alve olar carcinoma (LAG) and a fibrosarcoma (FS), induced platelet aggregation and plasma coagulation (P<0.05). Pretreatment of both tumor lines with a CO X inhibitor did not block the tumor cell induced platelet aggregation (TCIP A). COX [12(S)-HTT] and LOX [12(S)-HETE], metabolites of washed platelets ( WP), alone or co-incubated with LAC or FS cells, were analyzed. We observed higher 12(S)-HETE release with respect to 12(S)HHT when WP were co-incubat ed with LAC cells. With both neoplastic cell (NC) lines prothrombin time (P T) was shortened. Pretreatment of NC with iodoacetic acid, soybean trypsin inhibitor or Factor X-deficient plasma increased the PT. These results indi cate that AA metabolites play a role on the procoagulation and platelet agg regation induced by mesenchymal and epithelial murine cancers. (C) 2000 Har court Publishers Ltd.