FGF signaling inhibits the proliferation of human myeloma cells and reduces c-myc expression

Multiple myeloma is a cancer of antibody producing plasma cells whose etiology is unknown. FGF signaling has been implicated in myeloma pathogenesis but its precise role remains unclear. Here, we investigate the biochemical and phenotypic consequences of FGF stimulation in several different human myeloma cell lines. We find that FGF signaling inhibits cell cycle progression in two lines and surprisingly, reduces the expression of c-myc while turning on c-fos. In several other lines, FGF signaling does not affect proliferation rate, including cells harboring translocated FGF Receptor 3. When cells are presented with a growth arrest signal, FGF addition induces cell death. By showing that FGF signaling inhibits mitogenesis and induces apoptosis, we demonstrate novel effects of activating this ubiquitous signaling pathway in multiple myeloma.