Inhibitory effect of T-614 on tumor necrosis factor-alpha induced cytokineproduction and nuclear factor-kappa B activation in cultured human synovial cells

Objective. To investigate the mechanism of the immunosuppressive effect of T-614 [N-(3-formylamino-4-oxo-6-phenoxy-4H-chromen-7-yl)methanesulfonamide] , a new antirheumatic drug whose clinical efficacy has been determined for the treatment of patients with rheumatoid arthritis (RA), Methods. RA synov ial fibroblast-like cells were cultured with tumor necrosis factor-alpha (T NF-alpha, 10 ng/ml) in the presence or absence of T-614. After incubation, cytokine production was measured by ELISA. Expression of interleukin 6 (IL- 6) and IL-8 mRNA was examined by real-time quantitative reverse transcripta se-polymerase chain reaction analysis and TNF-alpha induced nuclear factor- kappaB (NF-kappaB) activation was observed using immunostaining with an ant ibody against NF-kappaB p65. Results. T-614 suppressed TNF-alpha induced pr oduction of IL-6, IL-8, and monocyte chemoattractant protein 1, and also re duced the accumulation of IL-6 and IL-8 mRNA in a concentration dependent m anner. T-614 interfered with the TNF-alpha induced translocation of NF-kapp aB to the nucleus from the cytoplasm, Conclusion. Inhibition of NF-kappaB a ctivation and transcription of proinflammatory cytokines by T-614 contribut es to its clinical antirheumatic effect.