title: Secretion of DNA synthesis factor (DSF) by A431 cells that can grow in protein-free medium.
abstract: A431 cells grew in protein-free Coon's modified Ham's F12 medium at a similar rate to that in medium supplemented with calf serum and secreted a growth factor capable of stimulating DNA synthesis in BALB/c3T3 cells. This factor had strong affinity for heparin and was partially purified from the conditioned medium by heparin-Sepharose affinity chromatography and molecular sieving on Bio-Gel P-60. The apparent molecular weight of the factor was 20-30K. Its activity was inhibited by heparin at concentrations of above 0.03 microgram/ml.
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000503:physiopathology*; D002455:Cell Division; D002460:Cell Line; D002846:Chromatography, Affinity; D003470:Culture Media; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D006133:Growth Substances / Q000378:metabolism; D006493:Heparin / Q000378:metabolism; D006801:Humans
chemical_list: D003470:Culture Media; D006133:Growth Substances; D005346:Fibroblast Growth Factors; D006493:Heparin