Expression of GM-CSF and a functional GM-CSF receptor in the human colon carcinoma cell line SW403

Only little is known about the expression of a functional granulocyte-macrophage colony-stimulating factor receptor (GMR) and its ligands in human colon carcinoma cell lines. To obtain more information on this subject, we investigated the human colon carcinoma cell line SW403, and we were able to demonstrate the constitutive synthesis of a 85-kDa GMR in SW403 cells. After stimulation with 10% fetal calf serum, GM-CSF transcripts were expressed as well. The incubation of SW403 cells with GM-CSF resulted in an intensive down-regulation of the activity of the interferon-gamma-receptor gene, which could be reconstituted by simultaneous addition of an anti-GM-CSF antibody. GM-CSF induced an activation of tyrosine-phosphorylated protein kinases with molecular weights in the range of 30 to 210 kDa, but it had no effect on the DNA synthesis of SW403 cells.