CONDITIONED MEDIA FROM A RENAL-CELL CARCINOMA CELL-LINE DEMONSTRATES THE PRESENCE OF BASIC FIBROBLAST GROWTH-FACTOR

In a previous report, we demonstrated the isolation and purification o f a heparin binding growth factor from human renal carcinoma, and sugg ested that this growth factor may play a role in the neovascularity an d growth of the tumor. In this report, we demonstrate that the growth of the renal cell carcinoma cell line RC29 is stimulated by the additi on of exogenous fibroblast growth factor (FGF), epidermal growth facto r (EGF) and transforming growth factor alpha (TGFalpha). Also, media c onditioned by this cell line was able to stimulate growth of the A431 vulvar tumor cell line, known for its high concentration of EGF recept ors, 3T3 fibroblasts, human umbilical vein (HUV) cells and RC29 cells. Using heparin-sepharose chromatography and then SDS polyacrylamide ge l electrophoresis (PAGE), we were able to demonstrate several proteins in the conditioned media of the RC29 cell line. Using Western blot an alysis, we detected that at least one of the proteins expressed in thi s conditioned media was FGF and that it belongs to the basic, not acid ic, family of fibroblast growth factors. These findings suggest that r enal tumors may express growth factors that may play a direct role in maintaining their unrestricted proliferation.