Clustering of discrete cell properties essential for tumorigenicity and metastasis. II. Studies of Syrian hamster embryo fibroblasts transformed by Rous sarcoma virus.

Tumorigenic and metastasizing activities (TGA; MA) and susceptibility, or resistance to H2O2 and PGE-releasing activity (H2O2R + PGEs+ phenotype) have been examined in 6 Syrian hamster embryo cell strains transformed in vitro with Rous sarcoma viruses (Schmidt-Ruppin and Prague strains). Early observations of extremely high level of TGA and even MA of RSV-SR-transformants never selected in vivo have been confirmed. The correspondence of these properties with a high level of expression of H2O2R + PGEs+ phenotype and its clustering character were demonstrated in 4 RSV-SR transformants, while significantly lower expression of all these characteristics, including TGA, was observed in 2 RSV-Prague transformants. High level of spontaneous MA was noticed in some RSV-SR transformants. A tumor cell line induced in vivo by RSV-SR did not differ from the cell strain transformed in vitro by RSV-SR. Inhibition of H2O2R + PGEs+ phenotype in one of RSV-SR transformants was obtained with non-toxic doses of BCNU and indomethacin, leading to a marked decrease of TGA.