Elaboration of granulocyte-macrophage colony-stimulating factor by human tumor cell lines and normal urothelium.

A total of 72 cell conditioned media (CCM) were screened for their ability to stimulate colony formation by human granulopoietic progenitor cells. Granulocyte-macrophage (GM) colony-stimulating factor(s) (CSF) were found in CCM of nine tumor cell lines, two primary urinary bladder tumors, and three epithelial cell cultures of normal urinary tract. The most active medium came from urinary bladder carcinoma cell line 5637. CSF released by the 5637 cell line induced dose-dependent GM colony formation from human fetal, normal adult, and CML bone marrow (BM) and from mouse BM. Human fetal and normal adult BM formed more colonies when stimulated with 5637 CCM than with peripheral blood leukocyte (PBL) feeder layers, while CML BM produced more colonies with PBL feeder layers. CCM from 5637 was more active in stimulating GM colony formation than human placenta conditioned medium (PCM) and PHA-LCM. 5637 CCM produced in serum-free hormone-supplemented medium was nearly equipotent and can serve as suitable starting material for purification.