STEM-CELL FACTOR AND INTERLEUKIN-6, ALONE OR IN COMBINATION WITH GRANULOCYTE-COLONY-STIMULATING FACTOR, DO NOT AFFECT THE GROWTH OF SOLID TUMOR-CELL LINES

Hematopoietic growth factors (HGFs) are glycoproteins that control hem opoiesis. They have potential usefulness in a range of clinical condit ions including the treatment of patients with myelosuppression induced by chemotherapy. Among HGFs, Stem Cell Factor (SCF) and Interleukin 6 (IL-6) are attracting interest for their capacity to stimulate early hematopoietic progenitors. Furthermore, their use in combination with late-acting growth factors with a more lineage-restricted potential (s uch as granulocyte colony-stimulating factor, G-CSF) might be expected to offer optimal marrow stimulation and usefulness in clinical oncolo gy. Since nonhematopoietic malignant cells may express receptors for H GFs and respond to these peptides in vitro, we investigated clonal gro wth H-3-thymidine incorporation and cell cycle analysis by flow cytome try of 5 human solid tumor cell lines under the influence of SCF and I L-6 with or without G-CSF. Our experiments show that these cytokines h ave no effects on the proliferative capacity of the cell lines tested. Based on our and previously reported data, the use of these HGFs can be considered safe in cancer patients.