A novel human myeloid leukemia cell line, NKM-1, coexpressing granulocyte colony-stimulating factor receptors and macrophage colony-stimulating factor receptors.

A novel human myeloid leukemia cell line, NKM-1, was established from a patient with acute myeloid leukemia (FAB classification M2). The cells were positive for myeloperoxidase staining and cluster of differentiation 15 cell surface antigen. Radiolabeled recombinant human granulocyte (G) colony-stimulating factor (CSF) was used, and 60 specific binding sites/cell with a Kd 100 pmol/liter were demonstrated on the cell surface. 125I-G-CSF binding was not inhibited by interleukin-3, granulocyte-macrophage CSF, or macrophage (M) CSF. NKM-1 cells also expressed M-CSF receptors detected by c-fms mRNA expression. In concordance with the receptor expression, NKM-1 cells proliferated in response to exogenous G-CSF or M-CSF in a dose-dependent manner (0.1-100 ng/ml), while interleukin-3 or granulocyte-macrophage CSF had no effect. Colony-forming capacity of NKM-1 cells in semisolid agar was also enhanced with the addition of 10 ng/ml of G-CSF or M-CSF but decreased at higher concentrations. During CSF stimulation, no remarkable changes were observed morphologically and phenotypically. The stimulatory effect of G-CSF and M-CSF on the cell growth was additive. Neither G-CSF-binding capacity nor c-fms mRNA expression was altered by pretreatment with M-CSF or G-CSF, respectively. This cell line may provide a useful in vitro model for the study of CSF roles in myeloid leukemia cell proliferation.