ABSTRACT
The bromodomain and extraterminal domain (BET) family proteins recognize acetyl-lysine (Kac) at the histone tail through two tandem bromodomains, i.e., BD1 and BD2, to regulate gene expression. BET proteins are attractive therapeutic targets in cancer due to their involvement in oncogenic transcriptional activation, and bromodomains have defined Kac-binding pockets. Here, we present DW-71177, a potent BET inhibitor that selectively interacts with BD1 and exhibits strong antileukemic activity. X-ray crystallography, isothermal titration calorimetry, and molecular dynamic studies have revealed the robust and specific binding of DW-71177 to the Kac-binding pocket of BD1. DW-71177 effectively inhibits oncogenes comparable to the pan-BET inhibitor OTX-015, but with a milder impact on housekeeping genes. It efficiently blocks cancer-associated transcriptional changes by targeting genes that are highly enriched with BRD4 and histone acetylation marks, suggesting that BD1-selective targeting could be an effective and safe therapeutic strategy against leukemia.
Subject(s)
Leukemia, Myeloid, Acute , Transcription Factors , Humans , Transcription Factors/metabolism , Histones , Nuclear Proteins , Quinoxalines/pharmacology , Leukemia, Myeloid, Acute/drug therapy , Cell Cycle Proteins/metabolism , Bromodomain Containing ProteinsABSTRACT
Our previous study revealed that the ethanolic extract of Justicia procumbens ameliorates ovalbumin-induced airway inflammation and airway hyper-responsiveness in a mouse model of asthma. However, the mechanism of action of the extract remains unknown. In this study, we prepared DW2008S, an optimized and standardized powder extracted from J. procumbens using anhydrous ethanol, and investigated its anti-asthmatic effect and mechanism of action. Our results showed that DW2008S contains two major ingredients, justicidin A (JA) and justicidin B (JB), which selectively inhibit T helper 2 (Th2) cell responses in concanavalin A-activated spleen cells and polarized Th2 cells. Blockade of T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domains (TIGIT) using a neutralizing antibody also selectively inhibited Th2 cell responses. Furthermore, DW2008S regulated TIGIT expression in the mice and cultured cells. Additionally, DW2008S and JA antagonized human adenosine receptor A3 (A3 AR), which mediates mast cell-dependent inflammation and bronchoconstriction. DW2008S and JB inhibited human phosphodiesterase 4 (PDE4), which is known to cause bronchoconstriction; however, the required concentrations were higher than those needed to affect TIGIT . These findings suggest that DW2008S can potentially ameliorate Th2-driven airway inflammation and bronchoconstriction through negative regulation of TIGIT and blockade of A3 AR and PDE4 activities.
Subject(s)
Anti-Asthmatic Agents/therapeutic use , Asthma/drug therapy , Justicia/chemistry , Plant Extracts/therapeutic use , Animals , Anti-Asthmatic Agents/pharmacology , Antibodies, Neutralizing/pharmacology , Asthma/pathology , Cyclic Nucleotide Phosphodiesterases, Type 4/metabolism , Dioxolanes/pharmacology , Disease Models, Animal , Female , Inflammation/immunology , Inflammation/pathology , Lignans/pharmacology , Mice, Inbred BALB C , Plant Extracts/pharmacology , Protective Agents/pharmacology , Protective Agents/therapeutic use , Receptor, Adenosine A3/metabolism , Receptors, Immunologic/metabolism , Th2 Cells/drug effects , Th2 Cells/immunologyABSTRACT
DW2008 is an anhydrous ethanol extract of Justicia procumbens produced by Dong-Wha Pharmaceutical, Inc., Co. as a candidate anti-asthmatic drug. In this study, DW2008 selectively reduced T helper 2 (Th2) cytokines in mouse splenocytes and ameliorated ovalbumin-induced airway inflammation by downregulating pulmonary infiltration of differential inflammatory cells and Th2 cytokines more than a decoction or ethanol extract of J. procumbens did in a mouse asthma model. DW2008 also significantly inhibited airway hyperresponsiveness and reduced the thickness of the airway epithelium. HPLC analysis showed that the major peaks (justicidin A and B) of DW2008 were higher than those of the other extracts. Justicidin A and B significantly suppressed Th2 cytokine levels in mouse spleen cells and exhibited a protective effect in ovalbumin-induced airway inflammation. Our findings indicate that DW2008 effectively inhibits allergic airway inflammatory reactions and airway hyperresponsiveness in a mouse model of asthma, suggesting its potential as an anti-asthmatic agent.
