ABSTRACT
A promising therapeutic approach to diminish pathological inflammation is to inhibit the increased production and/or biological activity of proinflammatory cytokines (e.g., TNF-alpha, IL-6). The production of proinflammatory cytokines is controlled at the gene level by the activity of transcription factors, such as NF-kappaB. Phosphatidylinositol 3-kinase (PI3K), a lipid kinase, is known to induce the activation of NF-kappaB. Given this, we hypothesized that inhibitors of PI3K activation would demonstrate anti-inflammatory potential. Accordingly, we studied the effects of a preferential p110alpha/gamma PI3K inhibitor (compound 8C; PIK-75) in inflammation-based assays. Mechanism-based assays utilizing human cells revealed that PIK-75-mediated inhibition of PI3K activation is associated with dramatic suppression of downstream signaling events, including AKT phosphorylation, IKK activation, and NF-kappaB transcription. Cell-based assays revealed that PIK-75 potently and dose dependently inhibits in vitro and in vivo production of TNF-alpha and IL-6, diminishes the induced expression of human endothelial cell adhesion molecules (E-selectin, ICAM-1, and VCAM-1), and blocks human monocyte-endothelial cell adhesion. Most importantly, PIK-75, when administered orally in a therapeutic regimen, significantly suppresses the macroscopic and histological abnormalities associated with dextran sulfate sodium-induced murine colitis. The efficacy of PIK-75 in attenuating experimental inflammation is mediated, at least in part, due to the downregulation of pertinent inflammatory mediators in the colon. Collectively, these results provide first evidence that PIK-75 possesses anti-inflammatory potential. Given that PIK-75 is known to exhibit anti-cancer activity, the findings from this study thus reinforce the cross-therapeutic functionality of potential drugs.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Enzyme Inhibitors/pharmacology , Hydrazones/pharmacology , Inflammation Mediators/metabolism , Inflammation/metabolism , NF-kappa B/metabolism , Phosphoinositide-3 Kinase Inhibitors , Protein Subunits/antagonists & inhibitors , Sulfonamides/pharmacology , Animals , Anti-Inflammatory Agents, Non-Steroidal/metabolism , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Cell Adhesion , Cell Line , Colitis/drug therapy , Colitis/immunology , E-Selectin/metabolism , Endothelial Cells/cytology , Endothelial Cells/metabolism , Enzyme Activation , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/metabolism , Enzyme Inhibitors/therapeutic use , Humans , Hydrazones/metabolism , Hydrazones/toxicity , I-kappa B Kinase/metabolism , Inflammation/drug therapy , Intercellular Adhesion Molecule-1/metabolism , Interleukin-6/antagonists & inhibitors , Mice , Mice, Inbred BALB C , Molecular Structure , Monocytes/cytology , Monocytes/metabolism , NF-kappa B/genetics , Phosphatidylinositol 3-Kinases/metabolism , Protein Subunits/metabolism , Signal Transduction , Sulfonamides/metabolism , Sulfonamides/toxicity , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Vascular Cell Adhesion Molecule-1/metabolismABSTRACT
A series of novel 1,2,4-oxadiazole, phthalimide, amide and other derivatives of ISO-1 were synthesized and probed for inhibition of macrophage migration inhibitory factor (MIF) activity. Several compounds inhibited MIF enzymatic activity at levels better than ISO-1. Of note, compounds 7, 22, 23, 24, 25 and 27 inhibited the spontaneous secretion/release/recognition of MIF from freshly isolated human peripheral blood mononuclear cells and, more importantly, inhibited the MIF-induced production of interleukin-6 (IL-6) and/or interleukin-1beta (IL-1beta) significantly better than ISO-1.
Subject(s)
Anti-Inflammatory Agents/chemical synthesis , Isoxazoles/chemistry , Receptors, Immunologic/antagonists & inhibitors , Amides/chemistry , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Cell Line , Humans , Interleukin-1beta/metabolism , Interleukin-6/metabolism , Isoxazoles/chemical synthesis , Isoxazoles/pharmacology , Oxadiazoles/chemistry , Phthalimides/chemistry , Receptors, Immunologic/metabolismABSTRACT
A promising therapeutic approach to diminish pathological inflammation is to inhibit the synthesis and/or biological activity of macrophage migration inhibitory factor (MIF). Prior studies have shown that intraperitoneal administration of small-molecule inhibitors targeting the catalytic pocket of MIF (e.g., ISO-1) elicits a therapeutic effect in mouse inflammation models. However, it remains to be elucidated whether these tautomerase activity inhibitors block the synthesis and/or biological activity of MIF. In this study, we investigated and compared the activity of representative MIF inhibitors from isoxazole series (fluorinated analog of ISO-1; ISO-F) and substituted quinoline series (compound 7E; 7E). Our results demonstrate that ISO-F is a more potent MIF inhibitor than 7E. Both ISO-F and 7E do not inhibit MIF synthesis but "bind-onto" MIF thereby blocking its recognition. However, in contrast to 7E, ISO-F docks well in the active site of MIF and also has a stronger binding affinity towards MIF. In line with these observations, ISO-F, but not 7E, robustly inhibits the biological function of MIF. Most importantly, ISO-F, when administered orally in a therapeutic regimen, significantly suppresses dextran sulphate sodium (DSS)-induced murine colitis. This study, which provides mechanistic insights into the anti-inflammatory efficacy of ISO-F, is the first documented report of in vivo anti-inflammatory efficacy of a MIF inhibitor upon oral administration. Moreover, the findings from this study reinforce the potential of catalytic site of MIF as a target for eliciting therapeutic effect in inflammatory disorders. Compounds (e.g., ISO-F) that block not only the recognition but also the biological function of MIF are potentially attractive for reducing pathological inflammation.
