PRODUCTION OF MULTIPLE GROWTH-FACTORS BY A HUMAN NONSMALL CELL LUNG-CARCINOMA CELL-LINE

The IPT cell line, derived from an undifferentiated bronchial carcinoma, produced, in conditioned medium, immunoreactive basic fibroblast growth factor (bFGF), insulin-like growth factors I and II (IGF-I and IGF-II), epidermal growth factor (EGF), transforming growth factor alpha (TGFalpha), and transforming growth factor beta-2 (TGFbeta2) in its latent form, but not platelet-derived growth factor (PDGF), tumour necrosis factor alpha (TNFalpha), or transforming growth factor beta-1 (TGFbeta1). Comparative studies of growth stimulation of human umbilical vein (HUV) endothelial cells indicated that the growth factors detected in 1PT-conditioned medium do not solely account for its proliferative effects on these cells. These results support previous characterization studies [1,2] that suggest the production of a potentially novel tumour-derived endothelial cell growth factor by the 1PT cell line.