In vitro growth effects of colony-stimulating factors in ovarian cancer

Human recombinant colony-stimulating factors may be used to treat or prevent neutropenia caused by marrow toxic chemotherapeutic agents administered to patients with cancer. Despite their common clinical use, little is known about the potential adverse effects that these cytokines may have on the growth of malignant cells. Indeed, several in vitro reports have indicated that colony-stimulating factors may act as stimulating growth factors in some human malignancies. To evaluate these effects in ovarian cancer, we investigated the possible growth effects of granulocyte colony-stimulating factor (G-CSF/Filgrastim) and granulocyte-macrophage colony-stimulating factors (GM-CSF/Sargramostim) on four established ovarian cancer cell lines, as well as five primary ovarian cancer cultures over a wide range of pharmacologic doses. Cell viability was measured by an ATP bioluminescence assay and expressed as a percentage of untreated control cultures. G-CSF showed no growth-stimulating effects in any of the four established cell lines tested. In the OVCAR-3 cell line, a decrease in growth (> 10%) was seen at 10, 100, and 1000 ng/ml after 5 days of continuous treatment. In the same cell line, GM-CSF caused an increase (> 10%) in growth at the same doses. However, these changes did not demonstrate statistical significance in a dose-dependent fashion. In the five primary cultures treated with G-CSF, only one demonstrated statistically significant increases in growth in a dose-dependent manner. GM-CSF treatment had no significant growth alterations in these same five primary cultures. These results would suggest that colony-stimulating factors may act as growth factors in some but not all ovarian cancer cells. Further investigations into the receptor status of ovarian cancer cells for these cytokines are underway to clarify this issue.