Comparison of procoagulant activity in tissue culture medium from normal and transformed fibroblasts.

Abstract

Abstract A serine protease procoagulant has been identified in tumor extracts. This study sought to determine whether this protease is produced by both normal and cancerous tissues or is unique to the malignant state. Serum-free medium (SFM) from cultured V2 carcinoma and parietal yolk sac carcinoma cells contained procoagulant activity that was inhibited by dilsopropylfluorophosphate (DFP) similar to that from extracts of V2 carcinoma, suggesting that cultured malignant cells produce the protease. SFM from normal Chinese hamsters and Syrian hamster (SHF) embryo fibroblasts contained procoagulant activity that was not inactivated by DFP similar to that for tissue thromboplastin. In contrast, SFM from SV40-transformed Chinese hamster embryo fibroblasts and SHF lines contained procoagulant activity that was completely inhibited by DFP and initiated coagulation in Factor VII-deficient plasma. SFM from chemically transformed SHF cells contained a DFP-sensitive procoagulant that did not initiate coagulation in Factor VII-deficient plasma. Analysis of procoagulant activities in SFM from normal and transformed SHF cells with Syrian hamster plasma showed from 3 to more than 200 times greater activity than with human plasma and confirmed the DFP sensitivity of the procoagulant activity from the transformed cells but not the normal fibroblasts. Normal fibroblasts produce procoagulant activity that is not DFP sensitive, and it resembles tissue thromboplastin. Malignant and transformed cells produce a serine protease procoagulant activity that is tentatively identified as cancer procoagulant A.