Background: The inflammasome is a multimolecular complex that regulates the processing of the pro-inflammatory cytokine interleukin-1β.Results: Inhibitors of deubiquitinase (DUB) enzymes inhibited the release of interleukin-1β.Conclusion: DUBs regulate assembly of the inflammasome.Significance: DUBs may represent new anti-inflammatory drug targets for the treatment of inflammatory disease.

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Summary Eeyarestatin 1 (ES1) inhibits p97-dependent protein degradation, Sec61-dependent protein translocation into the endoplasmic reticulum (ER), and vesicular transport within the endomembrane system. Here, we show that ES1 impairs Ca 2+ homeostasis by enhancing the Ca 2+ leakage from mammalian ER. A comparison of various ES1 analogs suggested that the 5-nitrofuran (5-NF) ring of ES1 is crucial for this effect. Accordingly, the analog ES24, which conserves the 5-NF domain of ES1, selectively inhibited protein translocation into the ER, displayed the highest potency on ER Ca 2+ leakage of ES1 analogs studied and induced Ca 2+ -dependent cell death. Using small interfering RNA-mediated knockdown of Sec61α, we identified Sec61 complexes as the targets that mediate the gain of Ca 2+ leakage induced by ES1 and ES24. By interacting with the lateral gate of Sec61α, ES1 and ES24 likely capture Sec61 complexes in a Ca 2+ -permeable, open state, in which Sec61 complexes allow Ca 2+ leakage but are translocation incompetent.

The synthesis is reported here of two novel series of inhibitors of human NAD(P)H quinone oxidoreductase-1 (NQO1), an enzyme overexpressed in several types of tumor cell. The first series comprises substituted symmetric dicoumarol analogues; the second series contains hybrid compounds where one 4-hydroxycoumarin system is replaced by a different aromatic moiety. Several compounds show equivalent or improved NQO1 inhibition over dicoumarol, both in the presence and in the absence of added protein. Further, correlation is demonstrated between the ability of these agents to inhibit NQO1 and computed binding affinity. We have solved the crystal structure of NQO1 complexed to a hybrid compound and find good agreement with the in silico model. For both MIA PaCa-2 pancreatic tumor cells and HCT116 colon cancer cells, dicoumarol shows the greatest toxicity of all compounds. Thus, we provide a computational, synthetic, and biological platform to generate competitive NQO1 inhibitors with superior pharmacological properties to dicoumarol. This will allow a more definitive study of NQO1 activity in cells, in particular, its drug activating/detoxifying properties and ability to modulate oncoprotein stability.