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Tretbar M, Schliehe-Diecks J, von Bredow L, Tan K, Roatsch M, Tu JW, Kemkes M, Sönnichsen M, Schöler A, Borkhardt A, Bhatia S, Hansen FK. Preferential HDAC6 inhibitors derived from HPOB exhibit synergistic antileukemia activity in combination with decitabine. Eur J Med Chem 2024; 272:116447. [PMID: 38714044 DOI: 10.1016/j.ejmech.2024.116447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 04/22/2024] [Accepted: 04/22/2024] [Indexed: 05/09/2024]
Abstract
Histone deacetylase 6 (HDAC6) is an emerging drug target to treat oncological and non-oncological conditions. Since highly selective HDAC6 inhibitors display limited anticancer activity when used as single agent, they usually require combination therapies with other chemotherapeutics. In this work, we synthesized a mini library of analogues of the preferential HDAC6 inhibitor HPOB in only two steps via an Ugi four-component reaction as the key step. Biochemical HDAC inhibition and cell viability assays led to the identification of 1g (highest antileukemic activity) and 2b (highest HDAC6 inhibition) as hit compounds. In subsequent combination screens, both 1g and especially 2b showed synergy with DNA methyltransferase inhibitor decitabine in acute myeloid leukemia (AML). Our findings highlight the potential of combining HDAC6 inhibitors with DNA methyltransferase inhibitors as a strategy to improve AML treatment outcomes.
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Affiliation(s)
- Maik Tretbar
- Institute for Drug Discovery, Medical Faculty, Leipzig University, Brüderstraße 34, 04103, Leipzig, Germany
| | - Julian Schliehe-Diecks
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Lukas von Bredow
- Institute for Drug Discovery, Medical Faculty, Leipzig University, Brüderstraße 34, 04103, Leipzig, Germany
| | - Kathrin Tan
- Department of Pharmaceutical and Cell Biological Chemistry, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Martin Roatsch
- Institute for Drug Discovery, Medical Faculty, Leipzig University, Brüderstraße 34, 04103, Leipzig, Germany
| | - Jia-Wey Tu
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Marie Kemkes
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Melf Sönnichsen
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Andrea Schöler
- Institute for Drug Discovery, Medical Faculty, Leipzig University, Brüderstraße 34, 04103, Leipzig, Germany
| | - Arndt Borkhardt
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Sanil Bhatia
- Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany.
| | - Finn K Hansen
- Department of Pharmaceutical and Cell Biological Chemistry, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany.
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Kraft FB, Enns J, Honin I, Engelhardt J, Schöler A, Smith ST, Meiler J, Schäker-Hübner L, Weindl G, Hansen FK. Groebke Blackburn Bienaymé-mediated multi-component synthesis of selective HDAC6 inhibitors with anti-inflammatory properties. Bioorg Chem 2024; 143:107072. [PMID: 38185013 DOI: 10.1016/j.bioorg.2023.107072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 12/19/2023] [Accepted: 12/27/2023] [Indexed: 01/09/2024]
Abstract
Histone deacetylases (HDACs) are a class of enzymes that cleave acyl groups from lysine residues of histone and non-histone proteins. There are 18 human HDAC isoforms with different cellular targets and functions. Among them, HDAC6 was found to be overexpressed in different types of cancer. However, when used in monotherapy, HDAC6 inhibition by selective inhibitors fails to show pronounced anti-cancer effects. The HDAC6 enzyme also addresses non-histone proteins like α-tubulin and cortactin, making it important for cell migration and angiogenesis. Recently, the NLRP3 inflammasome was identified as an important regulator of inflammation and immune responses and, importantly, HDAC6 is critically involved the activation of the inflammasome. We herein report the design, synthesis and biological evaluation of a library of selective HDAC6 inhibitors. Starting from the previously published crystal structure of MAIP-032 in complex with CD2 of zHDAC6, we performed docking studies to evaluate additional possible interactions of the cap group with the L1-loop pocket. Based on the results we synthesized 13 novel HDAC6 inhibitors via the Groebke-Blackburn-Bienaymé three component reaction as the key step. Compounds 8k (HDAC1 IC50: 5.87 μM; HDAC6 IC50: 0.024 μM; selectivity factor (SF1/6): 245) and 8m (HDAC1 IC50: 3.07 μM; HDAC6 IC50: 0.026 μM; SF1/6: 118) emerged as the most potent and selective inhibitors of HDAC6 and outperformed the lead structure MAIP-032 (HDAC1 IC50: 2.20 μM; HDAC6 IC50: 0.058 μM; SF1/6: 38) both in terms of inhibitory potency and selectivity. Subsequent immunoblot analysis confirmed the high selectivity of 8k and 8m for HDAC6 in a cellular environment. While neither 8k and 8m nor the selectivity HDAC6 inhibitor tubastatin A showed antiproliferative effects in the U-87 MG glioblastoma cell line, compound 8m attenuated cell migration significantly in wound healing assays in U-87 MG cells. Moreover, in macrophages compounds 8k and 8m demonstrated significant inhibition of LPS-induced IL1B mRNA expression and TNF release. These findings suggest that our imidazo[1,2-a]pyridine-capped HDAC6 inhibitors may serve as promising candidates for the development of drugs to effectively treat NLRP3 inflammasome-driven inflammatory diseases.
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Affiliation(s)
- Fabian B Kraft
- Department of Pharmaceutical and Cell Biological Chemistry, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121 Bonn, Germany
| | - Jana Enns
- Department of Pharmacology and Toxicology, Pharmaceutical Institute, University of Bonn, Gerhard-Domagk-Str.3, 53121 Bonn, Germany
| | - Irina Honin
- Department of Pharmaceutical and Cell Biological Chemistry, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121 Bonn, Germany
| | - Jonas Engelhardt
- Department of Pharmacology and Toxicology, Pharmaceutical Institute, University of Bonn, Gerhard-Domagk-Str.3, 53121 Bonn, Germany
| | - Andrea Schöler
- Institute for Drug Discovery, Medicinal Faculty, University Leipzig, Brüderstraße 34, 04103 Leipzig, Germany
| | - Shannon T Smith
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Jens Meiler
- Institute for Drug Discovery, Medicinal Faculty, University Leipzig, Brüderstraße 34, 04103 Leipzig, Germany; Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Linda Schäker-Hübner
- Department of Pharmaceutical and Cell Biological Chemistry, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121 Bonn, Germany
| | - Günther Weindl
- Department of Pharmacology and Toxicology, Pharmaceutical Institute, University of Bonn, Gerhard-Domagk-Str.3, 53121 Bonn, Germany
| | - Finn K Hansen
- Department of Pharmaceutical and Cell Biological Chemistry, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121 Bonn, Germany.
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König B, Watson PR, Reßing N, Cragin AD, Schäker-Hübner L, Christianson DW, Hansen FK. Difluoromethyl-1,3,4-oxadiazoles Are Selective, Mechanism-Based, and Essentially Irreversible Inhibitors of Histone Deacetylase 6. J Med Chem 2023; 66:13821-13837. [PMID: 37782298 PMCID: PMC10591924 DOI: 10.1021/acs.jmedchem.3c01345] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Histone deacetylase 6 (HDAC6) is an important drug target in oncological and non-oncological diseases. Most available HDAC6 inhibitors (HDAC6i) utilize hydroxamic acids as a zinc-binding group, which limits therapeutic opportunities due to its genotoxic potential. Recently, difluoromethyl-1,3,4-oxadiazoles (DFMOs) were reported as potent and selective HDAC6i but their mode of inhibition remained enigmatic. Herein, we report that DFMOs act as mechanism-based and essentially irreversible HDAC6i. Biochemical data confirm that DFMO 6 is a tight-binding HDAC6i capable of inhibiting HDAC6 via a two-step slow-binding mechanism. Crystallographic and mechanistic experiments suggest that the attack of 6 by the zinc-bound water at the sp2 carbon closest to the difluoromethyl moiety followed by a subsequent ring opening of the oxadiazole yields deprotonated difluoroacetylhydrazide 13 as active species. The strong anionic zinc coordination of 13 and the binding of the difluoromethyl moiety in the P571 pocket finally result in an essentially irreversible inhibition of HDAC6.
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Affiliation(s)
- Beate König
- Department of Pharmaceutical and Cell Biological Chemistry, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, Bonn 53121, Germany
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Paris R Watson
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Nina Reßing
- Department of Pharmaceutical and Cell Biological Chemistry, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, Bonn 53121, Germany
| | - Abigail D Cragin
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Linda Schäker-Hübner
- Department of Pharmaceutical and Cell Biological Chemistry, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, Bonn 53121, Germany
| | - David W Christianson
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Finn K Hansen
- Department of Pharmaceutical and Cell Biological Chemistry, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, Bonn 53121, Germany
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