Objective: To evaluate the effect of hematopoietic growth factors (HGF) on the proliferation of non-hematopoietic cells such as fibroblasts and epithelial cells of normal and tumoral origin.
Methods: The lymphoid factor IL-2 and the myeloid HGF assayed were IL-3, G-CSF, GM-CSF and M-CSF. The cellular proliferation was determined by measuring the amount of crystal violet dye incorporation by cells through spectrophotometry.
Results: All myeloid HGF tested stimulated the proliferation of cell lines 5637, CaLo and L-929. These results suggest that the stromal cells can be induced to proliferate by myeloid growth factors hinting to a bilateral interaction between these two types of cells as it is known that stromal cells in turn secrete HGF. We also observed that for the mouse fibroblastic and epithelial cells, IL-2 was unable to induce proliferation in normal cells but had a strong effect on transformed cells. Finally we discuss our observation that tumour cells responded to IL-2 as a possible mechanism for an immune escape by these cells through IL-2 depletion.