Inhibition of interferon-gamma-activated nuclear factor-kappa B by cyclosporin A: A possible mechanism for synergistic induction of apoptosis by interferon-gamma and cyclosporin A in gastric carcinoma cells.
We previously reported synergistic induction of apoptosis by IFN-gamma plus either cyclosporin A (CsA) or tacrolimus (FK506) in gastric carcinoma cells. In this study, we aimed to elucidate the mechanism for this synergistic induction of apoptosis. IFN-gamma plus CsA synergistically induced caspase-3 mediated apoptosis in gastric carcinoma cells. Although IFN-gamma induced activation of signal transducer and activator of transcription1 (STAT1) and expression of interferon regulatory factor-1 (IRF-1) mRNA, IFN-gamma alone was not able to induce caspase-3 activation and apoptosis. When gastric carcinoma cells were treated with cyclohexamide, a protein synthesis inhibitor, following IFN-gamma pretreatment, caspase-3 was activated, and apoptosis was markedly induced. These findings suggest the existence of IFN-gamma-induced anti-apoptotic pathway and we evaluated the effect of IFN-gamma and CsA on calcium-sensitive nuclear factor-kappa B (NF-kappa B) activation. IFN-gamma increased intracellular calcium ion concentration ([Ca(2+)](i)) consisting of a spike and a sustained phase, and the latter was completely abrogated by CsA. Activation of NF-kappa B occurred in response to IFN-gamma, and which was markedly inhibited by either CsA or FK506. NF-kappa B decoy also enhanced the cytotoxic effect of IFN-gamma. These results suggest that IFN-gamma may simultaneously induce the STAT1-mediated apoptotic pathway and the anti-apoptotic pathway through calcium-activated NF-kappa B and that inhibition of the latter by CsA may result in dominance of the apoptosis-inducing pathway.
Beppu
Kiichiro
K
Department of Cancer Therapy and Research, Graduate School of Medical Sciences, Kyusyu University, Fukuoka 812-8582, Japan.
Morisaki
Takashi
T
Matsunaga
Hisashi
H
Uchiyama
Akihiko
A
Ihara
Eikichi
E
Hirano
Katsuya
K
Kanaide
Hideo
H
Tanaka
Masao
M
Katano
Mitsuo
M
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D002118:Calcium / Q000378:metabolism; D002277:Carcinoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D016572:Cyclosporine / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D004357:Drug Synergism; D006801:Humans; D050856:Interferon Regulatory Factor-1; D007371:Interferon-gamma / Q000494:pharmacology*; D008954:Models, Biological; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D010750:Phosphoproteins / Q000096:biosynthesis / Q000235:genetics; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D050794:STAT1 Transcription Factor; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D016559:Tacrolimus / Q000494:pharmacology; D015534:Trans-Activators / Q000378:metabolism; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D004268:DNA-Binding Proteins; C494257:IRF1 protein, human; D050856:Interferon Regulatory Factor-1; D016328:NF-kappa B; D010750:Phosphoproteins; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D015534:Trans-Activators; D007371:Interferon-gamma; D016572:Cyclosporine; D003513:Cycloheximide; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D002118:Calcium; D016559:Tacrolimus