An endothelial cell growth factor derived from human lung carcinoma cells grown in serum-free medium.

A factor that stimulates the proliferation of human umbilical vein endothelial cells has been shown to be present in serum-free medium conditioned by the prior growth of a cell line (1PT) derived from a poorly differentiated bronchial carcinoma. Preliminary characterization of this factor has revealed that it is a heat-labile, acid-stable proteinaceous material, the activity of which is not diminished by treatment with a reducing agent. In its partially purified state it has been shown to be anionic and to be associated with material exhibiting a broad molecular weight range of 35 X 10(3) to 100 X 10(3). It does not bind strongly to heparin-Sepharose and its mitogenic effect on endothelial cells is not potentiated by heparin. These properties suggest that this factor may differ from other previously described tumour-derived endothelial mitogens.