Macrophage-colony stimulating factor inhibits the growth of human ovarian cancer cells in vitro

The effect of macrophage-colony stimulating factor (M-CSF), which regulates the growth and differentiation of haematopoietic progenitor cells on the growth of ovarian cancer cells was investigated in three ovarian cancer cell lines in vitro. The spontaneous growth of these cells was significantly inhibited by the addition of M-CSF in a concentration-dependent manner over 96 h of culturing. The maximum response was obtained with 10 ng/ml (3857 U/ml) of M-CSF by counting the viable cell number using the trypan blue exclusion assay. [H-3]-thymidine incorporation by these cells was also suppressed following a 96-h incubation with M-CSF. The inhibitory effect of M-CSF was reversed by the addition of anti-M-CSF monoclonal antibody. Flow cytometric analysis revealed that the treated ovarian cancer cells arrested at the G0/G1 phase of the cell cycle. These cells expressed M-CSF receptors on their surface as detected by Scatchard plot analysis using I-125-labelled M-CSF. These results indicate that M-CSF has an antitumour activity for ovarian cancer cells and suggest that it can be applied for the treatment of this disease. (C) 2000 Elsevier Science Ltd. All rights reserved.