3 research outputs found

    Inhibition of Inducible Nitric Oxide Synthase Expression by a Novel Small Molecule Activator of the Unfolded Protein Response

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    The transcription of inducible nitric oxide synthase (iNOS) is activated by a network of proinflammatory signaling pathways. Here we describe the identification of a small molecule that downregulates the expression of iNOS mRNA and protein in cytokine-activated cells and suppresses nitric oxide production in vivo. Mechanistic analysis suggests that this small molecule, erstressin, also activates the unfolded protein response (UPR), a signaling pathway triggered by endoplasmic reticulum stress. Erstressin induces rapid phosphorylation of eIF2α and the alternative splicing of XBP-1, hallmark initiating events of the UPR. Further, erstressin activates the transcription of multiple genes involved in the UPR. These data suggest an inverse relationship between UPR activation and iNOS mRNA and protein expression under proinflammatory conditions

    KD5170, a novel mercaptoketone-based histone deacetylase inhibitor that exhibits broad spectrum antitumor activity in vitro and in vivo

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    Abstract Histone deacetylase (HDAC) inhibitors have garnered significant attention as cancer drugs. These therapeutic agents have recently been clinically validated with the market approval of vorinostat (SAHA, Zolinza) for treatment of cutaneous T-cell lymphoma. Like vorinostat, most of the small-molecule HDAC inhibitors in clinical development are hydroxamic acids, whose inhibitory activity stems from their ability to coordinate the catalytic Zn 2+ in the active site of HDACs. We sought to identify novel, nonhydroxamate-based HDAC inhibitors with potentially distinct pharmaceutical properties via an ultra-high throughput small molecule biochemical screen against the HDAC activity in a HeLa cell nuclear extract. An A-mercaptoketone series was identified and chemically optimized. The lead compound, KD5170, exhibits HDAC inhibitory activity with an IC 50 of 0.045 Mmol/L in the screening biochemical assay and an EC 50 of 0.025 Mmol/L in HeLa cell -based assays that monitor histone H3 acetylation. KD5170 also exhibits broad spectrum classe
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