Search Results (551)

Corneal problems, such as delayed and incomplete wound repair, are frequent in diabetes, affecting up to 70% of diabetic patients. In skin, histone deacetylases (HDACs) have been previously found to repress expression of the glycerol channel aquaporin-3 (AQP3), the deficiency of which delays corneal wound healing. We hypothesized that the pan-HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) would improve corneal healing in diabetic mice. Diabetic and normoglycemic C57BL/6J male and female mice were subjected to corneal debridement. Wounds were treated topically with vehicle or SAHA every four hours until they healed. Treatment with SAHA improved wound healing in both normoglycemic and hyperglycemic male mice but, unexpectedly, no changes were detected in female mice. In male mice interleukin-1beta (IL-1β) and tumor necrosis factor (TNF) were significantly increased in diabetic corneas, and SAHA reduced their expression, returning IL-1β and TNF to levels comparable to those in normoglycemic mice regardless of treatment. In normoglycemic male mice, AQP3 levels were not changed in the cornea with SAHA treatment but the expression of AQP3 was increased in the wound’s edge relative to the rest of the cornea. In vitro SAHA treatment of human corneal epithelial cells (HCECs) significantly increased protein expression of AQP3, important for corneal wound healing, but had no effect on ROS production. In conclusion, treatment with SAHA improved corneal wound healing, not only in male mice with diabetes and delayed wound healing but also in normoglycemic male mice; therefore, SAHA could potentially be repurposed as a topical treatment clinically to improve corneal wound healing. Full article

Histone acetylation and deacetylation are key regulators of gene expression and are frequently dysregulated in cancer, contributing to tumorigenesis and drug resistance. Overexpression of histone deacetylases (HDACs) in many cancer types leads to silencing of tumor suppressor genes and uncontrolled proliferation. Tumors often rely on epigenetic mechanisms to escape therapy and develop resistance. This study aimed to identify novel compounds that selectively target cancer cells while minimizing toxicity to non-cancerous cell lines. A series of novel HDAC inhibitors was evaluated using the Differential Nuclear Staining (DNS) assay, flow cytometry, and HDAC inhibition assays. These assays assessed cytotoxicity, selectivity, and mechanisms of cell death. Among seven compounds tested, VS-186B exhibited the highest cytotoxicity and Selective Cytotoxicity Index (SCI), particularly against the human Jurkat T-cell leukemia cell line. Flow cytometry experiments (Annexin V-FITC, ROS, JC-1, and Caspase-3/7 assays) revealed that VS-186B induced apoptosis. VS-186B was more cytotoxic than Curcumin and Vorinostat across most of the cell lines tested and was more specific to hematological cells. Connectivity Map (CMap) analysis showed strong similarity to genes affected by known HDAC inhibitors. Subsequently, HDAC enzymatic assays confirmed that VS-186B inhibits Class I and II HDACs in a dose-dependent manner. VS-186B exhibits promising anticancer potential as a selective HDAC inhibitor since it induces apoptosis in cancer cells without significant cytotoxicity to non-cancerous lines with a similar gene expression profile to known HDAC inhibitors. These findings support further development of VS-186B as an epigenetic treatment for leukemia/lymphoma. Full article

Epigenetics garnered significant scientific interest in recent decades, with histone acetylation emerging as the most prevalent epigenetic deregulation process observed in malignancies. The clinical application of histone deacetylase (HDAC) inhibitors faced challenges, including complex therapeutic mechanisms and inconsistent treatment outcomes. In Acute Lymphoblastic Leukemia (ALL), the dysregulation of HDAC activity presents a promising therapeutic target. To investigate cellular-level tumor suppression by HDAC inhibitors possessing potent target engagement, we developed two novel azetidine-hydroxamic acid conjugates. Compared to N-hydroxy-4-((quinolin-4-ylamino)methyl)benzamide (NBU-1), N-hydroxy-6-((5-methyl-4-nitro-9-oxo-9,10-dihydroacridin-1-yl)amino)hexanamide (NBU-2) demonstrated enhanced inhibitory activity against HDAC1 (class I) and HDAC6 (class II) with IC₅₀ values of 7.75 nM and 7.34 nM, respectively, consistent with binding mode analysis and docking energy calculations. In vitro evaluation across 12 tumor cell lines revealed NBU-2’s potent antiproliferative effects, particularly against the ALL-derived Jurkat cells (IC₅₀ = 0.86 μM). Subsequent mechanistic studies were therefore conducted in this ALL model. Proteomic profiling indicated its potential involvement in modulating AKT signaling and histone modification pathways in Jurkat cells. Mechanistic investigations demonstrated that NBU-2 elevated histone acetylation while suppressing AKT phosphorylation. This compound altered apoptotic regulators by downregulating Bcl-2 and Bcl-XL expression while upregulating BAX, ultimately activating Caspase-9 and Caspase-3 to induce apoptosis. Cell cycle analysis revealed NBU-2-mediated G0/G1 arrest through reduced expression of Cyclin D1 and CDK4, diminished Rb protein phosphorylation, and increased p21 expression. These findings propose a strategic framework for developing next-generation HDAC inhibitors for ALL treatment and elucidating their mechanism-specific anti-cancer actions. Full article

The gut–brain axis (GBA) is a critical area of research for understanding the pathogenesis of neuroinflammatory and neurodegenerative diseases. Metabolites produced by the gut microbiota, particularly short-chain fatty acids (SCFAs), act as key mediators in this bidirectional communication. While the roles of acetate, propionate, and butyrate are well-established, valeric acid (VA), a five-carbon SCFA, is poorly understood. This comprehensive review explores VA as a gut-derived physiological epigenetic modulator, examining its microbial biosynthesis and systemic effects. This review discusses how VA acts as a selective histone deacetylase inhibitor (HDACi), particularly targeting Class I HDACs, to modulate gene expression and exert neuroprotective and anti-inflammatory effects. The analysis compares VA with its pharmacological analog, valproic acid (VPA), a well-known but non-selective HDACi. This comparison highlights how VA’s physiological nature may offer a more targeted and safer intervention. In conclusion, elucidating VA’s role as a microbiome-derived epigenetic regulator would open promising avenues for therapeutic strategies that directly connect gut and CNS health within the GBA. Full article

Triple-negative breast cancer (TNBC) remains a leading cause of cancer-related mortality in women, characterized by its aggressive nature and limited therapeutic options. TNBC is defined by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression, which excludes patients from targeted endocrine and HER2-directed therapies, contributing to poor prognosis. This study investigates BKS-112, a potent histone deacetylase 6 (HDAC6) inhibitor, for its anticancer activity against TNBC using MDA-MB-231 cells. We assessed HDAC protein expression and their prognostic implications, alongside in vitro experiments analyzing cell viability, apoptosis, autophagy, and colony formation. BKS-112 exhibited dose- and time-dependent reductions in cell viability, significant morphological alterations, and decreased colony formation. The compound increased the acetylation of histones H3, H4, and α-tubulin while downregulating HDAC6 expression and activity. Additionally, BKS-112 reduced cell migration, demonstrating anti-metastatic potential. It induced G1 phase cell cycle arrest and modulated key regulators, including cyclins and cyclin-dependent kinases (CDKs). Apoptosis was promoted through mitochondrial pathways, evidenced by changes in Bcl-2, Bax, and caspase activation. BKS-112 also elevated reactive oxygen species (ROS) levels, affecting apoptosis-related PI3K/AKT signaling. Autophagy was triggered by upregulating LC3 and Atg-7 expression. Collectively, these findings suggest that BKS-112 exerts robust anticancer effects by inducing cell cycle arrest, apoptosis, and autophagy, highlighting its therapeutic promise for TNBC treatment. Full article

Background/Objectives: Dilated cardiomyopathy (DCM) is a prevalent and life-threatening heart muscle disease often caused by titin (TTN) truncating variants (TTNtv). While TTNtvs are the most common genetic cause of heritable DCM, the precise downstream regulatory mechanisms linking TTN deficiency to cardiac dysfunction and maladaptive fibrotic remodeling remain incompletely understood. This study aimed to identify key epigenetic regulators of TTN-mediated gene expression and explore their potential as therapeutic targets, utilizing human patient data and in vitro models. Methods: We analyzed RNA sequencing (RNA-seq) data from left ventricles of non-failing donors and cardiomyopathy patients (DCM, HCM, PPCM) (GSE141910). To model TTN deficiency, we silenced TTN in human iPSC-derived cardiomyocytes (iPSC-CMs) and evaluated changes in cardiac function genes (MYH6, NPPA) and fibrosis-associated genes (COL1A1, COL3A1, COL14A1). We further tested the effects of TMP-195, a class IIa histone deacetylase (HDAC) inhibitor, and individual knockdowns of HDAC4/5/7/9. Results: In both human patient data and the TTN knockdown iPSC-CM model, TTN deficiency suppressed MYH6 and NPPA while upregulating fibrosis-associated genes. Treatment with TMP-195 restored NPPA and MYH6 expression and suppressed collagen genes, without altering TTN expression. Among the HDACs tested, HDAC5 knockdown was most consistently associated with improved cardiac markers and reduced fibrotic gene expression. Co-silencing TTN and HDAC5 replicated these beneficial effects. Furthermore, the administration of TMP-195 enhanced the modulation of NPPA and COL1A1, though its impact on COL3A1 and COL14A1 was not similarly enhanced. Conclusions: Our findings identify HDAC5 as a key epigenetic regulator of maladaptive gene expression in TTN deficiency. Although the precise mechanisms remain to be clarified, the ability of pharmacological HDAC5 inhibition with TMP-195 to reverse TTN-deficiency-induced gene dysregulation highlights its promising translational potential for TTN-related cardiomyopathies. Full article

(Background) Retinoblastoma is the most common intraocular malignancy in childhood, primarily caused by mutations in the RB1 gene. However, increasing evidence highlights the significant role of epigenetic mechanisms, particularly DNA methylation and histone acetylation, in tumor initiation and progression. This review aims to summarize and critically assess recent findings on how DNA methylation and histone acetylation contribute to the pathogenesis of retinoblastoma, and to explore their potential role as diagnostic biomarkers and therapeutic targets. (Methods) We searched the databases PubMed, Scopus, and ScienceDirect following PRISMA guidelines. Eligible studies were English-language, open-access articles published within the last ten years, including cohort studies, research articles, and case reports. After rigorous screening, 18 studies were included in the final analysis. (Results) Aberrant DNA methylation was found to inactivate tumor suppressor genes (RB1, RASSF1A, p16INK4A, MGMT) and promote oncogenesis through hypermethylation of regulatory elements. Similarly, histone acetylation’s dysregulation contributed to chromatin remodeling and overexpression of oncogenic factors such as SYK, GALNT8, and lincRNA-ROR. Elevated histone deacetylase (HDAC) activity was also linked to tumor cell proliferation, metastasis, and treatment resistance. Epigenetic inhibitors targeting these pathways demonstrated promising therapeutic potential. (Conclusions) DNA methylation and histone acetylation play a crucial role in the epigenetic regulation of genes implicated in retinoblastoma. Their dysregulation promotes tumorigenesis, and targeting these mechanisms represents a promising avenue for novel diagnostic and therapeutic strategies in pediatric oncology. Full article

A three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis incorporating ligand-receptor docking alignment and molecular dynamic (MD) simulations was conducted to elucidate the potent inhibitory effects of a series of benzamide derivatives on histone deacetylase 1 (HDAC1). A comparison between ligand-based (LB) and receptor-based (RB) 3D-QSAR models using molecular docking alignment produced statistically significant results. Steric and electrostatic contour maps provided insights into the interactions surrounding the benzamide ring, revealing that an increase in electron density enhances inhibitory activity. Furthermore, MD simulations were employed to investigate protein-ligand interactions in greater detail, yielding outcomes consistent with those from 3D-QSAR and molecular docking studies. This integrated approach of molecular docking, 3D-QSAR, and energy decomposition analysis derived from MD simulations, provides a valuable framework for the rational design of more potent HDAC1 inhibitors, facilitating the synthesis of highly effective anti-tumor compounds based on benzamide scaffolds. Full article

Aromatic ring systems appear ubiquitously in active pharmaceutical substances, such as FDA-approved histone deacetylase inhibitors. However, these rings reduce the water solubility of the molecules, which is a disadvantage during application. To address this problem, azaborine rings may be substituted for conventional aromatic ring systems. These are obtained by replacing two adjacent carbon atoms with boron and nitrogen. Incorporating B–N analogs in place of aromatic rings not only enhances structural diversity but also provides a strategy to navigate around patent-protected scaffolds. We synthesized azaborines, which are isosteric to naphthalene and indole, and utilized them as capping units for HDAC inhibitors. These molecules were attached to various aliphatic and aromatic linkers with different zinc-binding units, used in established active compounds. Nearly half of the twenty-four molecules tested exhibited inhibitory activity against at least one of the enzymes HDAC1, HDAC4, or HDAC8, with three compounds displaying IC₅₀ values in the nanomolar range. We have therefore demonstrated that azaborine building blocks can be successfully incorporated into HDACis, resulting in a highly active profile. Consequently, it should be feasible to develop active substances containing azaborine rings against other targets. Full article

This work reports the crystallographic study of two benzenesulfonamides, 1 ((E)-N-benzyl-3-((benzylimino)methyl)-4-hydroxybenzenesulfonamide) and 2 (N-benzyl-3-(3-(N-benzylsulfamoyl)-2-oxo-2H-chromene-6-sulfonamide). These compounds share structural features with belinostat, an FDA-approved histone deacetylase (HDAC) inhibitor used in the treatment of peripheral T-cell lymphoma. Compound 1 contains one sulfonamide group, meanwhile compound 2 contains two sulfonamide moieties and presents four independent molecules in its unit cell. The crystal packing of 1 and 2 is mainly governed by N–H···O=S hydrogen bonding interactions. π → π* and n → π* stacking interactions also contribute to the molecular assembly. Hirshfeld surface (HS) analysis was carried out to further examine the intermolecular interactions of compounds 1 and 2, revealing that N–H∙∙∙O and C–H∙∙∙O hydrogen bonding interactions, along with O∙∙∙H/H∙∙∙O interactions, are the strongest contributors to the individual surfaces. Interaction energy analysis was also performed to evaluate the relative strength and nature of the intermolecular contacts. Additionally, molecular docking studies of compounds 1 and 2 were performed on the crystal structure of the enzyme HDAC2, an enzyme overexpressed in several cancers, particularly breast cancer. The results revealed that both compounds exhibit a binding mode and binding energies similar to those of belinostat, suggesting their potential as novel therapeutic agents. Full article

Histone deacetylases (HDACs) are crucial enzymes involved in the regulation of gene expression through chromatin remodeling, impacting numerous cellular processes, including cell proliferation, differentiation, and survival. In recent years, HDACs have emerged as therapeutic targets for neurodegenerative diseases (NDDs), such as Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease, given their role in modulating neuronal plasticity, neuroinflammation, and neuronal survival. HDAC inhibitors (HDACi) are small molecules that prevent the deacetylation of histones, thereby promoting a more relaxed chromatin structure and enhancing gene expression associated with neuroprotective pathways. Preclinical and clinical studies have demonstrated that HDACi can mitigate neurodegeneration, reduce neuroinflammatory markers, and improve cognitive and motor functions, positioning them as promising therapeutic agents for NDDs. Given the complexity and multifactorial nature of NDDs, therapeutic success will likely depend on multi-target drugs as well as new cellular and molecular therapeutic targets. Emerging evidence suggests that HDACi can modulate the function of astrocytes, a glial cell type critically involved in neuroinflammation, synaptic regulation, and the progression of neurodegenerative diseases. Consequently, HDACi targeting astrocytic pathways represent a novel approach in NDDs therapy. By modulating HDAC activity specifically in astrocytes, these inhibitors may attenuate pathological inflammation and promote a neuroprotective environment, offering a complementary strategy to neuron-focused treatments. This review aims to provide an overview of HDACs and HDACi in the context of neurodegeneration, emphasizing their molecular mechanisms, therapeutic potential, and limitations. Additionally, it explores the emerging role of astrocytes as targets for HDACi, proposing that this glial cell type could enhance the efficacy of HDACs-targeted therapies in NDD management. Full article

Background/Objective: Aberrant acetylation and methylation of histone and non-histone proteins contribute to carcinogenesis. Among non-histone proteins, wild-type (wt) p53 is particularly notable for the critical role that acetylation and methylation play in regulating its stability and function. Although with opposite outcomes, these post-translational modifications (PTMs) can also affect mutant forms of p53 (mutp53), which are frequently detected in cancers. These proteins may acquire oncogenic properties, activating signaling pathways that promote carcinogenesis. Acetylation activates wtp53, while this PTM has been shown to destabilize mutp53, reducing cancer aggressiveness and improving the efficacy of anticancer therapies. In this study, we investigated the possibility of targeting mutp53 in pancreatic cancer cells by using a combination of EZH2 and HDAC inhibitors. Methods: Western blotting, qRT-PCR, and ChIP experiments were performed to address this question. Results: We found that the EZH2 inhibitor Valemetostat (DS) in combination with the histone deacetylase inhibitor SAHA displaced the SET/TAF-Iβ oncoprotein from mutp53 and increased its interaction with the acetyltransferase p300, which was responsible for p53 acetylation. Moreover, mutp53 was downregulated, p21 was upregulated, and CHK1 was reduced, increasing DNA damage and leading to a stronger impairment of pancreatic cancer cell survival compared with single-agent treatments. Conclusions: Our results reveal that combining epigenetic drugs such as Valemetostat and SAHA could be exploited to target mutp53 and improve the outcome of treatments for aggressive tumors harboring it, such as in pancreatic cancer. Full article

Chemotherapy-induced peripheral neuropathy remains a significant side effect of cancer treatment, often requiring dose reductions or even discontinuation of therapy. Paclitaxel (PTX), a widely used chemotherapeutic agent for solid tumors, is particularly neurotoxic, and no effective treatment exists for paclitaxel-induced peripheral neuropathy (PIPN). Histone deacetylases (HDACs) are enzymes that remove acetyl groups from histone and non-histone proteins, including transcription factors and cytoskeletal components. This study evaluates the HDAC6 inhibitor ITF6475 for its potential to prevent PIPN and compares its effects with ricolinostat, a well-established HDAC6 inhibitor previously studied in cisplatin-induced neuropathy models. Female C57BL/6 mice received PTX vehicle (VEH) or PTX (70 mg/kg intravenously, once per week for four weeks), and the remaining four groups received PTX with co-treatment of either ricolinostat (50 mg/kg orally, daily) or ITF6475 (1, 6, or 12.5 mg/kg orally, daily). Neurophysiological assessments at the end of treatment showed a significant reduction in caudal sensory nerve action potential amplitude across all PTX-treated groups compared to the VEH group. At the same time, PTX treatment led to the development of mechanical allodynia. However, co-treatment with the HDAC6 inhibitor prevented significant differences compared to the VEH group. PTX-induced reduction in intraepidermal nerve fiber density was significantly prevented in the PTX + ITF6475 (1 mg/kg) group, and PTX-induced increase in neurofilament light levels was reduced in all ITF6475 co-treated groups. These findings support the potential of ITF6475 in preventing small fiber damage in a severe, chronic PIPN model. Full article

Background/Objectives: The effects of PD-L1 are mediated via its binding to the PD-1 receptor, which mediates the signals intracellularly to suppress T-cell responses. The expression levels of PD-L1 on cancer cells are an important indicator of immunosuppression and cause poor prognosis in several types of cancers. Therefore, the identification and characterization of mechanisms that regulate the expression of PD-L1 in cancer patients is very critical. Method: Our experiment was designed to determine the impact of histone deacetylase (HDAC) inhibitor on PD-L1 expression to reverse tumor-induced immunosuppression using H460 and HCC827 lung cancer cell lines. These cells were treated with the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA). PD-L1 expression levels were assessed along with key regulatory proteins, including p53, p21, acetyl-histones, DNMT3B, MGMT, and trimethyl histones. Results: In our experiments, suberoylanilide hydroxamic acid (SAHA) was able to reduce the expression of PD-L1 by 60% in a dose-dependent manner. While the level of PD-L1 was significantly reduced, a concurrent increase in levels of p53, p21, and acetyl histone levels were observed in H460 and HCC827 cells following SAHA treatment. Furthermore, SAHA treatment was able to decrease the levels of DNMT3B, MGMT, and tri-methyl histones. It appears that the decrease in PD-L1 expression observed is solely because of p53 or p21WAF1/CIP1-mediated negative control on the transcription process. Conclusion: Our results suggest that SAHA can be used along with immune checkpoint inhibitors to potentiate the therapeutic outcomes in patients with excessive immunosuppression due to PD-L1 expression. Full article

Neuroblastoma (NB) is an aggressive pediatric cancer, with high-risk patients facing a five-year survival rate of ~50%. Standard therapies, including surgery, chemotherapy, radiation, and immunotherapy, are associated with significant long-term toxicities and frequent relapse. Histone deacetylase (HDAC) inhibitors have emerged as promising agents for cancer therapy, given their role in modulating gene expression and tumor phenotypes. This study evaluated M344 [4-(dimethylamino)-N-(7-(hydroxyamino)-7-oxoheptyl)benzamide], an HDAC inhibitor, for its efficacy and mechanisms of action against NB. Analysis of clinical NB Gene Expression Omnibus data revealed advanced-stage tumors exhibit higher HDAC expression relative to early-stage samples. M344 treatment effectively increased histone acetylation, induced G0/G1 cell cycle arrest, and activated caspase-mediated cell death. Relative to vorinostat, an HDAC inhibitor in clinical use for lymphoma and clinical trials for NB, M344 displayed superior cytostatic, cytotoxic, and migration-inhibitory effects. In vivo, metronomic M344 dosing suppressed tumor growth and extended survival. Combination therapy with M344 and topotecan improved topotecan tolerability, while M344 co-administration with cyclophosphamide reduced tumor rebound post-therapy. In total, M344 demonstrated strong therapeutic potential for NB, offering improved tumor suppression, reduced off-target toxicities, and enhanced control of tumor growth post-therapy. These findings support further investigation of HDAC inhibitors, such as M344, for clinical application in NB treatment. Full article