PURIFICATION AND CHARACTERIZATION OF TWO PROCOAGULANTS FROM WALKER 256 CARCINOSARCOMA TUMORS,

Abstract

Activation of the coagulation system bytumor cells may play an important role in tumor growth and metastases. Becauseprocoagulant activities have been identified in different tumor cells by different investigators, effective comparison of these activities has been difficult. Therefore, we purified and characterized two different procoagulant proteins from the same Walker 256 tumors. The first procoagulant activity/platelet aggregating activity (PCA/PAA) was purified from a 1% CHAPS detergent extract oftumor homogenate followed by (NH4)2SO4 fractionation, anion exchange and hydrophobic chromatography. The protein had a molecular weight of 58,000, required phospholipid and an intact coagulation pathway from factor X through fibrinogen for activity, but did not require factors VII or IX forits procoagulant activity. The procoagulant activity was not inhibited by 5mMphenyl-methyl sulfonyl fluoride, iodoacetamide or phenanthroline; there was noevidence of proteinase activity. The PAA was due to thrombin generation during coagulation. The second procoagulant,cancer procoagulant (CP), was extracted from tumors in barbital buffer (pH 7.4) without detergent, purified by immunoaffinity (using a polyclonal goat antibody to CP from V2 carcinoma) and mercurial-benzoate affinity chromatography. CP had a molecular weight of 68,000, an isoelectric point of 4.8 and initiated coagulation by directly activating factor X in the coagulation system. CP was inhibited by Hg++ and iodoacetamide, cysteine proteinase inhibitors. The purified CP formed an immunodiffusion precipitin band against the polyclonal anti-CP goat antibody. Thus, thepurified CP had the same physicochemical, enzymatic and immunologic propertiesas CP from rabbit V2 carcinoma. Neither procoagulant had the properties of tissue factor. These results suggest that there aretwo distinct procoagulant activities inWalker 256 and that both may contributeto the coagulation abnormalities that are associated with tumor growthand metastases.