The differential role of    JAK-2   /   STAT-1    in the r   egulation of lipopolysaccharide-induced inducible nitric oxide synthase and cyclooxygenase-2 productions by CKD712   

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Inflammation is commonly associated with carcinogenesis. CKD712, an S enantiomer of YS 49, is under phase I clinical trial for the treatment of inflammatory diseases such as sepsis. It differentially regulates the induction of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2(COX-2) by lipopolysaccharide (LPS) in RAW 264.7 macrophage cells. Here we investigated how CKD712 affected the production of these enzymes when activated by LPS in RAW264.7 cells. CKD712 strongly inhibited iNOS induction, but showed a weak inhibitory effect on COX-2 induction in LPS-stimulated cells. Treatment with SP600125, a specific JNK inhibitor and TPCK, an inhibitor of NF-κB, but not the ERK inhibitor PD98059 or the p38 inhibitor SB203580, significantly inhibited LPS-mediated iNOS and COX-2 induction. However, AG490, a specific inhibitor of JAK-2/STAT-1, efficiently prevented LPS-mediated iNOS induction, but not induction of COX-2. CKD712 inhibited NF-κB (p65) activity and translocation, but failed to prevent JNK activation and completely blocked STAT-1 phosphorylation by LPS, suggesting that the NF-κB and JAK-2/STAT-1 pathways_but not the JNK pathway_are important for its action. Further, CKD712 induced upregulated heme oxygenase 1 (HO-1) gene expression in LPS-treated cells. Differential inhibition of iNOS and COX-2 were shown in LPS-activated HO-1 transfected cells. Taken together, we conclude that CKD712 can efficiently inhibit induction of iNOS rather than COX-2 by LPS in RAW 264.7 cells, by regulating the HO-1 and STAT-1 pathways. These results highlight another potential use of CKD712 as a therapeutic candidate against inflammatory diseases including cancer.