1-Arylsulfonyl-5-(N-hydroxyacrylamide)indolines Histone Deacetylase Inhibitors Are Potent Cytokine Release Suppressors

Histone Deacetylase 3-Directed PROTACs Have Anti-inflammatory Potential by Blocking Polarization of M0-like into M1-like Macrophages

Macrophage polarization plays a crucial role in inflammatory processes. The histone deacetylase 3 (HDAC3) has a deacetylase-independent function that can activate pro-inflammatory gene expression in lipopolysaccharide-stimulated M1-like macrophages and cannot be blocked by traditional small-molecule HDAC3 inhibitors. Here we employed the proteolysis targeting chimera (PROTAC) technology to target the deacetylase-independent function of HDAC3. We developed a potent and selective HDAC3-directed PROTAC, P7, which induces nearly complete HDAC3 degradation at low micromolar concentrations in both THP-1 cells and human primary macrophages. P7 increases the anti-inflammatory cytokine secretion in THP-1-derived M1-like macrophages. Importantly, P7 decreases the secretion of pro-inflammatory cytokines in M1-like macrophages derived from human primary macrophages. This can be explained by the observed inhibition of macrophage polarization from M0-like into M1-like macrophage. In conclusion, we demonstrate that the HDAC3-directed PROTAC P7 has anti-inflammatory activity and blocks macrophage polarization, demonstrating that this molecular mechanism can be targeted with small molecule therapeutics.

Development and Application of Indolines in Pharmaceuticals

In recent years, the incidence of cancer is high around the world, and the resistance of bacteria is increasing. To cope with the potentially adverse side effects of cancer chemotherapy and surgery, researchers are turning to the construction of new drug scaffolds. The indoline structure exists in a huge number of natural products, but drugs with indoline have only been formally studied in recent years. With the deepening of research, drugs containing indoline have played important roles in more disease treatment aspects, such as anti-tumor, anti-bacterial, anti-inflammatory and have been used as analgesics, to treat cardiovascular diseases and so on. The synthesis and pharmacological activity of indoline derivatives is summarized in this review in order to support the addition of the indoline component to the toolbox of medicinal chemists. This review focuses on the advantages of indoline compounds in development and synthesis of and for the use as anticancer drugs, antibacterial drugs, to treat cardiovascular diseases and as anti-inflammatory and analgesic drugs. Indoline structures are commonly found in natural and synthetic compounds with medicinal value and are now beginning to be exploited as the basic backbone of various drugs. As research continues, dihydroindoles and their derivatives will play a greater role in the medical field.

Effect of 3-subsitution of quinolinehydroxamic acids on selectivity of histone deacetylase isoforms

A series of 3-subsituted quinolinehydroxamic acids has been synthesised and evaluated for their effect on human lung cancer cell line (A549), human colorectal cancer cell line (HCT116) and HDAC isoforms 1, 2, 6, and 8. The results indicated that substitution at C3 of quinoline is favoured for HDAC6 selectivity. Two compounds (25 and 26) were also found to be potent anti-proliferative compounds with IC₅₀ values ranging from 1.29 to 2.13 µM against A549 and HCT116 cells. These compounds displayed remarkable selectivity for HDAC6 over other HDAC isoforms with nanomolar IC₅₀ values. Western blot analysis revealed that compounds of this series activate apoptotic caspase pathway as indicated by cleavage of caspase 3, 8, and 9 and also increase phosphorylated H2AX thus inducing DNA double strand fragmentation in a concentration dependent manner. Flow cytometric analysis also displayed a dose dependent increase of cell population in sub G1 phase.

Isoindoline scaffold-based dual inhibitors of HDAC6 and HSP90 suppressing the growth of lung cancer in vitro and in vivo

This study reports the synthesis of a series of 2-aroylisoindoline hydroxamic acids employing N-benzyl, long alkyl chain and acrylamide units as diverse linkers. In-vitro studies led to the identification of N-benzyl linker-bearing compound (10) and long chain linker-containing compound (17) as dual selective HDAC6/HSP90 inhibitors. Compound 17 displays potent inhibition of HDAC6 isoform (IC₅₀ = 4.3 nM) and HSP90a inhibition (IC₅₀ = 46.8 nM) along with substantial cell growth inhibitory effects with GI₅₀ = 0.76 μM (lung A549) and GI₅₀ = 0.52 μM (lung EGFR resistant H1975). Compound 10 displays potent antiproliferative activity against lung A549 (GI₅₀ = 0.37 μM) and lung H1975 cell lines (GI₅₀ = 0.13 μM) mediated through selective HDAC6 inhibition (IC₅₀ = 33.3 nM) and HSP90 inhibition (IC₅₀ = 66 nM). In addition, compound 17 also modulated the expression of signatory biomarkers associated with HDAC6 and HSP90 inhibition. In the in vivo efficacy evaluation in human H1975 xenografts, 17 induced slightly remarkable suppression of tumor growth both in monotherapy as well as the combination therapy with afatinib (20 mg/kg). Moreover, compound 17 could effectively reduce programmed death-ligand 1 (PD-L1) expression in IFN-γ treated lung H1975 cells in a dose dependent manner suggesting that dual inhibition of HDAC6 and HSP90 can modulate immunosuppressive ability of tumor area.

TIMP3 expression associates with prognosis in colorectal cancer and its novel arylsulfonamide inducer, MPT0B390, inhibits tumor growth, metastasis and angiogenesis

Tissue inhibitors of metalloproteinase 3 (TIMP3) are a major endogenous inhibitor of matrix metalloproteinase (MMPs) that inhibit tumor growth, invasion, metastasis and angiogenesis. In this study, we found that TIMP3 expression is associated with positive prognosis of colorectal cancer (CRC) clinicopathologically. Therefore, we developed a series of arylsulfonamide derivatives as TIMP3 inducers in order to define potential colorectal cancer therapeutic agent. Among these, MPT0B390 was selected for anti-tumor, anti-metastasis, and anti-angiogenesis property determination. Methods: The relationship between TIMP3 expression and clinical pathological features in colorectal patients and cell lines were determined by immunohistochemistry, bioinformatics analysis and western blotting. The anti-tumor function was validated by using MTT, apoptosis pathway detection and in vivo xenograft model for tumor growth inhibition determination. The anti-metastatic function was validated using a transwell migration assay, and using in vivo lung metastasis and liver metastasis models. The mechanism of MPT0B390-induced TIMP3 expression was further tested using qPCR and Chromatin IP assay. The anti-angiogenesis function was examined by using transwell migration assay, and in vivo Matrigel plug assay. Results: After screening candidate compounds, we identified MPT0B390 as an effective inducer of TIMP3. We showed that MPT0B390 induces TIMP3 expression significantly and inhibits CRC cell growth in vitro and in vivo. By inducing TIMP3 expression, MPT0B390 can also exert its anti-metastasis effect to inhibit CRC cell migration and invasion and downregulates migration markers such as uPA, uPAR, and c-Met. Subsequent Chromatin immunoprecipitation assay revealed that MPT0B390 can significantly inhibit EZH2 expression as well as its binding to TIMP3 promoter region to regulate TIMP3 induction. In addition to the anti-tumor and anti-metastasis capability, MPT0B390 can also induce TIMP3 expression in endothelial cells to inhibit tumor angiogenesis. Conclusion: These data suggest the potential therapeutic applications of the TIMP3 inducer, MPT0B390, for colorectal cancer treatment.

1-Aroylindoline-hydroxamic acids as anticancer agents, inhibitors of HSP90 and HDAC

A series of 1-aroylindoline-hydroxamic acids have been synthesized in the present study. The results of the biological evaluation led to the identification of compound 12 as dual HDAC6/HSP90 inhibitor. Compound 12 displayed striking inhibitory effects towards the HDAC6 isoform and HSP 90 protein with IC₅₀ values of 1.15 nM (HDAC6) and 46.3 nM (HSP90). Compound 12 also exhibited 113, 139 and 246 fold higher selectivity for HDAC6 over HDAC 1, HDAC 3 and HDAC 8 isoforms and was endowed with significant cytotoxic effects with GI₅₀ values ranging 1.04-1.61 μM against lung A549, colorectal HCT116, leukemia HL60, and EGFR T790M mutant lung H1975 cell lines. Another interesting finding of the study was substantial cytotoxic effects of compounds particularly against lung H1975 (NSCLC) cell lines with IC₅₀ = 0.26 μM which may be mediated through HSP90 inhibition. Compound 8 as such was devoid of HDAC inhibitory activity.

4-Indolyl-N-hydroxyphenylacrylamides as potent HDAC class I and IIB inhibitors in vitro and in vivo

A series of 4,5-indolyl-N-hydroxyphenylacrylamides, as HDAC inhibitors, has been synthesized and evaluated in vitro and in vivo. 4-Indolyl compounds 13 and 17 functions as potent inhibitors of HDAC1 (IC₅₀ 1.28 nM and 1.34 nM) and HDAC 2 (IC₅₀ 0.90 and 0.53 nM). N-Hydroxy-3-{4-[2-(1H-indol-4-yl)-ethylsulfamoyl]-phenyl}-acrylamide (13) inhibited the human cancer cell growth of PC3, A549, MDA-MB-231 and AsPC-1 with a GI₅₀ of 0.14, 0.25, 0.32, and 0.24 μM, respectively. In in vivo evaluations bearing prostate PC3 xenografts nude mice model, compound 13 suppressed tumor growth with a tumor growth inhibition (TGI) of 62.2%. Immunohistochemistry of protein expressions, in PC-3 xenograft model indicated elevated acetyl-histone 3 and prominently inhibited HDAC2 protein expressions. Therefore, compound 13 could be a suitable lead for further investigation and the development of selective HDAC 2 inhibitors as potent anti-cancer compounds.

The Search for Potent, Small-Molecule HDACIs in Cancer Treatment: A Decade After Vorinostat

Histone deacetylases (HDACs) play a crucial role in the remodeling of chromatin, and are involved in the epigenetic regulation of gene expression. In the last decade, inhibition of HDACs came out as a target for specific epigenetic changes associated with cancer and other diseases. Until now, more than 20 HDAC inhibitors (HDACIs) have entered clinical studies, and some of them (e.g., vorinostat, romidepsin) have been approved for the treatment of cutaneous T-cell lymphoma. This review provides an overview of current knowledge, progress, and molecular mechanisms of HDACIs, covering a period from 2011 until 2015.

Novel histone deacetylase inhibitor MPT0G009 induces cell apoptosis and synergistic anticancer activity with tumor necrosis factor-related apoptosis-inducing ligand against human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a frequent cause of cancer-related death; therefore, more effective anticancer therapies for the treatment of HCC are needed. Histone deacetylase (HDAC) inhibitors serve as promising anticancer drugs because they can induce cell growth arrest and apoptosis. We previously reported that 3-[1-(4-methoxybenzenesulfonyl)-2,3-dihydro-1H-indol-5-yl]-N-hydroxyacrylamide (MPT0G009)—a novel 1-arylsulfonyl-5-(N-hydroxyacrylamide)indolines compound—demonstrated potent pan-HDAC inhibition and anti-inflammatory effects. In this study, we evaluated the anti-HCC activity of MPT0G009 in vitro and in vivo. Growth inhibition, apoptosis, and inhibited HDAC activity induced by MPT0G009 were more potent than a marketed HDAC inhibitor SAHA (Vorinostat). Furthermore, MPT0G009-induced apoptosis of Hep3B cells was characterized by an increase in apoptotic (sub-G1) population, loss of mitochondrial membrane potential, activation of caspase cascade, increased levels of pro-apoptotic protein (Bim), and decreased levels of anti-apoptotic proteins (Bcl-2, Bcl-x_L, and FLICE-inhibitory protein); the downregulation FLIP by MPT0G009 is mediated through proteasome-mediated degradation and transcriptional suppression. In addition, combinations of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) with lower concentrations (0.1 μM) of MPT0G009 were synergistic in cell growth inhibition and apoptosis in HCC cells. In the in vivo model, MPT0G009 markedly reduced Hep3B xenograft tumor volume, inhibited HDAC activities, and induced apoptosis in the Hep3B xenografts. Our results demonstrate that MPT0G009 is a potential new candidate drug for HCC therapy.

2-(Phenylsulfonyl)quinoline N-hydroxyacrylamides as potent anticancer agents inhibiting histone deacetylase

This study reports the design and synthesis of 2-(phenylsulfonyl)quinoline N-hydroxyacrylamides (8a-k). Structure-activity relationship studies focusing on regio-effect of N-hydroxyacrylamide moiety and influence of the sulfonyl linker revealed that N-hydroxy-3-[3-(quinoline-2-sulfonyl)-phenyl]-acrylamide (8f) showed remarkable enzymatic and cellular activity. The GI50 values of 8f for HL-60, HCT116, PC-3, and A549 cells were found to be 0.29, 0.08, 0.15, and 0.27 μM, respectively. The compounds are therefore more potent than FDA approved PXD-101 and SAHA. They also have an effect on the acetylation degree of histone H3 and α-tubulin. In in vivo studies, 8f showed marked inhibition of the growth of HCT116 xenografts.

Azaindolylsulfonamides, with a more selective inhibitory effect on histone deacetylase 6 activity, exhibit antitumor activity in colorectal cancer HCT116 cells

A series of indolylsulfonylcinnamic hydroxamates has been synthesized. Compound 12, (E)-3-(3-((1H-pyrrolo[2,3-b]pyridin-1-yl)sulfonyl)phenyl)-N-hydroxyacrylamide, which has a 7-azaindole core cap, was shown to have antiproliferative activity against KB, H460, PC3, HSC-3, HONE-1, A549, MCF-7, TSGH, MKN45, HT29, and HCT116 human cancer cell lines. Pharmacological studies indicated that 12 functions as a potent HDAC inhibitor with an IC50 value of 0.1 μM. It is highly selective for histone deacetylase 6 (HDAC6) and is 60-fold more active than against HDAC1 and 223-fold more active than against HDAC2. It has a good pharmacokinetic profile with oral bioavailability of 33%. In in vivo efficacy evaluations in colorectal HCT116 xenografts, compound 12 suppresses tumor growth more effectively than SAHA (1, N-hydroxy-N'-phenyloctanediamide) and is therefore seen as a suitable candidate for further investigation.

Preclinical anti-arthritic study and pharmacokinetic properties of a potent histone deacetylase inhibitor MPT0G009

The pathology of rheumatoid arthritis includes synoviocyte proliferation and inflammatory mediator expression, which may result from dysregulated epigenetic control by histone deacetylase (HDAC). Thus, HDAC inhibitors may be useful for treating inflammatory disease. This was a preclinical study of the HDAC inhibitor, MPT0G009. The IC50 values of MPT0G009 for HDAC1, 2, 3, 6 and 8 enzymatic activities were significantly lower than those for the currently marketed HDAC inhibitor suberoylanilide hydroxamic acid (SAHA; vorinostat). In addition, MPT0G009 markedly inhibited cytokine secretion and macrophage colony-stimulating factor/receptor activator of nuclear factor kappa B ligand-induced osteoclastogenesis by macrophages (50 ng/ml each). These MPT0G009 effects on cytokine secretion and osteoclast formation were reduced by the overexpression of HDAC 1 (class I HDAC) and 6 (class II HDAC) in cells, suggesting that these effects were due to the inhibition of its activity. In an in vivo rat model, oral administration of MPT0G009 (25 mg/kg) significantly inhibited paw swelling and bone destruction. Furthermore, compared with SAHA, MPT0G009 exhibited longer half-life (9.53 h for oral administration) and higher oral bioavailability (13%) in rats. These results established the preclinical anti-arthritic efficacy and pharmacokinetic parameters of MPT0G009, which may provide a new therapeutic approach for treating inflammatory arthritis.

Small molecule inhibitors of histone acetyltransferases and deacetylases are potential drugs for inflammatory diseases

Lysine acetylation is a reversible post-translational modification (PTM) of cellular proteins and represents an important regulatory switch in signal transduction. Lysine acetylation, in combination with other PTMs, directs the outcomes as well as the activation levels of important signal transduction pathways such as the nuclear factor (NF)-κB pathway. Small molecule modulators of the 'writers' (HATs) and 'erasers' (HDACs) can regulate the NF-κB pathway in a specific manner. This review focuses on the effects of frequently used HAT and HDAC inhibitors on the NF-κB signal transduction pathway and inflammatory responses, and their potential as novel therapeutics.

Histone deacetylase inhibition improved cardiac functions with direct antifibrotic activity in heart failure

BACKGROUND

Histone deacetylases (HDACs), important epigenetic regulatory enzymes, can reduce cardiac hypertrophy and cardiac fibrosis. However, the mechanisms underlying the antifibrotic activity of HDAC inhibitors remain unclear. The purposes of this study were to evaluate the effects of an HDAC inhibitor on systolic heart failure (HF) and investigate the potential mechanisms.

METHODS

Echocardiographic, histologic, atrial natriuretic peptide (ANP), and Western blot measurements were performed in HF rats (isoproterenol 100 mg/kg, subcutaneous injection) with and without orally administered (100 mg/kg for 7 consecutive days) MPT0E014 (a novel HDAC inhibitor). Western blot, migration and proliferation assays were carried out on primary isolated cardiac fibroblasts with and without MPT0E014 (0.1 and 1 μM) for 24 h.

RESULTS

MPT0E014-treated HF rats (n = 6) had better fraction shortening (48 ± 2 vs. 33 ± 4%, p = 0.006) and smaller left ventricular end diastolic diameter (4.6 ± 0.2 vs. 5.6 ± 0.3 mm, p = 0.031) and systolic diameter (2.4 ± 0.2 vs. 3.9 ± 0.3 mm, p = 0.006) than HF (n = 7) rats. MPT0E014-treated HF rats had lower ANP, cardiac fibrosis, and angiotensin II type I receptor (AT1R), transforming growth factor (TGF)-β, and CaMKIIδ protein levels compared to HF rats. MPT0E014 (at 1 μM, but not 0.1 μM) decreased the migration and proliferation of cardiac fibroblasts. MPT0E014 (0.1 and 1 μM) decreased expression of the AT1R and TGF-β.

CONCLUSIONS

MPT0E014 improved cardiac contractility and attenuated structural remodeling in isoproterenol-induced dilated cardiomyopathy. The direct antifibrotic activity may have contributed to these beneficial effects.

Histone acetyltransferases are crucial regulators in NF-κB mediated inflammation

Post-translational modifications of proteins, such as acetylation, are important regulatory events in eukaryotic cells. Reversible acetylations of histones and non-histone proteins regulate gene expression and protein activity. Acetylation levels of proteins are regulated by a dynamic equilibrium between acetylation by (histone) acetyltransferases and deacetylation by (histone) deacetylases. Alterations in this equilibrium can result in pathological states. Inflammation is a physiological response that, under certain conditions, turns into a disease. This review focuses on the crucial regulatory roles of protein acetylation in NF-κB-mediated inflammation and the potential applications of small-molecule inhibitors of acetylation for the treatment of inflammatory diseases.