Differentiation of the rat myelomonocytic leukemia cell line c-WRT-7 by in vitro culture with the rat bone marrow preadipocyte cell line REC A16

Differentiation of the rat myelomonocytic leukemia cell line (c-WRT-7) was investigated, by co-culture with a rat embryonic bone marrow preadipose cell line (REC A16). Co-cultivation with REC A16, or with conditioned medium from REC A16 cultures (REC-CM), induced differentiation of c-WRT-7 cells to macrophages. A soluble factor(s) produced by REC A16 appeared to be responsible for the differentiation of c-WRT-7. Because REC-CM was associated with colony-stimulating activity on murine marrow progenitors, c-WRT-7 cells were cultured with various colony-stimulating factors (CSF) and it was found that macrophage CSF (M-CSF) significantly induced differentiation of c-WRT-7. We further demonstrated that both the colonystimulating and differentiation-inducing activities of REC-CM were significantly blocked by anti-M-CSF antiserum. These results suggest that the differentiation of c-WRT-7 is due to M-CSF produced by REC A16. Co-culture of these two cell lines should provide a useful model to study the mechanisms of interaction between leukemia cells and marrow stroma.Abbreviations CSF colony-stimulating facor - IL-1 interleukin-1 - LPS Lipopolysaccharide - REC-CM medium conditioned by REC A16This work was supported, in part, by grants-in-aid 02256102, 03252102 and 03670325 from the Ministry of Education, Science and Culture of Japan, and by grants-in-aid from the Fukuoka Anti-Cancer Society.