Interleukin-1-induced growth inhibition of human melanoma cells. Interleukin-1-induced antizyme expression is responsible for ornithine decarboxylase activity down-regulation.
Interleukin (IL)-1 is a multi-functional cytokine and regulates cell growth either positively or negatively. Previous studies have shown that IL-1-induced ornithine decarboxylase (ODC) activity down-regulation is involved in the anti-proliferative effect of IL-1 on human A375 melanoma cells. In this study, we examined the IL-1alpha-induced molecular events resulting in ODC activity down-regulation in C2-1, a A375 cell line stably transfected with human type I IL-1 receptor. Recombinant human (rh) IL-1alpha inhibited the growth and down-regulated the ODC activity of C2-1 cells in a dose-dependent manner. Kinetics studies showed that both the DNA synthesis and ODC activity of C2-1 cells progressively decreased from 12 h after IL-1 addition. Northern hybridization showed that IL-1 had no influence on ODC mRNA level. However, rhIL-1 induced both a decrease of ODC protein and an ODC-inhibiting activity in IL-1-treated C2-1 cells. IL-1 specifically up-modulated the mRNA level of antizyme, a protein essential for ODC regulation, but had little effect on its stability. IL-1-induced antizyme up-modulation preceded IL-1-induced down-regulation of ODC protein, ODC activity, and DNA synthesis in C2-1 cells. Run-on transcription analysis confirmed that the increased antizyme mRNA expression was due to elevated antizyme gene transcription. Furthermore, the action of IL-1 to inhibit the ODC activity and growth of C2-1 cells was blocked by expressing the antisense RNA of human antizyme in C2-1 cells. These results suggest that IL-1-induced antizyme expression is responsible for IL-1-induced ODC activity down-regulation in human melanoma cells.
Yang
D
D
Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Nagoya City University, Mizuho, Nagoya 467, Japan.
Hayashi
H
H
Takii
T
T
Mizutani
Y
Y
Inukai
Y
Y
Onozaki
K
K
D002455:Cell Division / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D008545:Melanoma / Q000201:enzymology* / Q000473:pathology; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects; D014407:Tumor Cells, Cultured
D004791:Enzyme Inhibitors; D007375:Interleukin-1; D016376:Oligonucleotides, Antisense; D011506:Proteins; D012333:RNA, Messenger; C031017:ornithine decarboxylase antizyme; D009955:Ornithine Decarboxylase; D013755:Tetradecanoylphorbol Acetate