Production of transforming growth factors by simian sarcoma virus-transformed cells
van Zoelen, E.J.; van Rooijen, M.A.; van Oostwaard, T.M.; de Laat, S.W.
Cancer Research 47(6): 1582-1587
1987
ISSN/ISBN: 0008-5472 PMID: 3028611 Document Number: 301408
Cellular transformation of normal rat kidney (NRK) cells by simian sarcoma virus (SSV) results in a complete loss of the cellular requirement of externally added polypeptide growth factors for proliferation. Moreover, SSV-transformed NRK cells have a strongly reduced ability to bind both external platelet-derived growth factor and epidermal growth factor, when compared to nontransformed NRK cells. Analysis of serum-free medium conditioned by SSV-transformed NRK cells shows that this cell line secretes both types .alpha. and .beta. transforming growth factor (TGF). The level of TGF.alpha. production (300 ng/liter conditioned medium) by SSV-transformed NRK is among the highest described to date. Since addition of TGF.alpha. and .beta. in combination is sufficient to induce phenotypic transformation of NRK cells, it is concluded that although expression of the sis oncogene is essential for transformation, expression of additional genes may be required for the phenotypic alterations accompanying complete cellular transformation.