Interferon-gamma inhibits cell replication, but not pp60src activity of RSV-transformed fibroblasts.
The present study analyzes the effect of murine IFN-gamma on DNA synthesis, ornithine decarboxylase activity and phosphorylation of pp60src of Rouse sarcoma virus transformed cells. When natural or recombinant IFN-gamma was added to quiescent SR-BALB or L1210 cells, stimulated with fetal calf serum, only the highest IFN-gamma concentrations (2000 U/ml) inhibited DNA synthesis of both tumor lines. By contrast, lower IFN-concentrations (20-200 U/ml) inhibited the DNA synthesis of L1210 but not of SR-BALB tumor cells. A similar pattern of inhibition was observed when ornithine decarboxylase activity was analyzed. Finally, when the levels of phosphorylation in SR-BALB cells were analyzed after IFN-gamma treatment, no difference with untreated controls was observed, even at the highest concentrations. These results suggest that SR-BALB tumor cells are insensitive to IFN-gamma and that src oncogene activity is not affected at IFN-concentrations inhibiting cell growth.
D000818:Animals; D001358:Avian Sarcoma Viruses / Q000502:physiology*; D002455:Cell Division; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D002472:Cell Transformation, Viral; D004247:DNA / Q000096:biosynthesis; D005347:Fibroblasts; D007371:Interferon-gamma / Q000494:pharmacology*; D051379:Mice; D015688:Oncogene Protein pp60(v-src); D009955:Ornithine Decarboxylase / Q000378:metabolism; D010766:Phosphorylation; D012191:Retroviridae Proteins / Q000378:metabolism*
D012191:Retroviridae Proteins; D007371:Interferon-gamma; D004247:DNA; D015688:Oncogene Protein pp60(v-src); D009955:Ornithine Decarboxylase