[Inhibitory effect of recombinant human interferon gamma on human osteoblastic osteosarcoma cells (SaOS2)].

Abstract

Recent studies have suggested that interleukin-1 or tumor necrosis factor-stimulated bone resorption is mediated by osteoclast-activating factor elaborated by osteoblastic cells. Since recombinant interferon gamma inhibits stimulation of bone resorption by these cytokines, we examined here the effects of recombinant human interferon gamma (rhIFN-G) on DNA synthesis and alkaline phosphatase (ALP) activity of a human osteoblastic osteosarcoma cell line, SaOS2, under preconfluent culture conditions. Addition of rhIFN-G to the cells markedly inhibited their DNA synthesis and ALP activity in a dose-dependent fashion. However, the inhibition was not dependent on the culture time. The highest inhibitory effect was observed in 10% serum-containing culture medium. The inhibitory effect on DNA synthesis was not eliminated by addition of indomethacin, a cyclooxygenase inhibitor. Furthermore, combination of rhIFN-G and recombinant human tumor necrosis factor alpha inhibited their DNA synthesis and the ALP activity in synergistic fashion. Therefore, these data suggest that rhIFN-G is a potent inhibitor for human osteoblastic cells.