Suberoylanilide Hydroxamic Acid Research Articles

Suberoylanilide Hydroxamic Acid (SAHA) Treatment Reveals Crosstalk Among Proteome, Phosphoproteome, and Acetylome in Nasopharyngeal Carcinoma Cells.

Suberoylanilide hydroxamic acid (SAHA), a famous histone deacetylase (HDAC) inhibitor, has been utilized in clinical treatment for cutaneous T-cell lymphoma. Previously, the mechanisms underlying SAHA anti-tumor activity mainly focused on acetylome. However, the characteristics of SAHA in terms of other protein posttranslational modifications (PTMs) and the crosstalk between various modifications are poorly understood. Our previous work revealed that SAHA had anti-tumor activity in nasopharyngeal carcinoma (NPC) cells as well. Here, we reported the profiles of global proteome, acetylome, and phosphoproteome of 5–8 F cells upon SAHA induction and the crosstalk between these data sets. Overall, we detected and quantified 6,491 proteins, 2,456 phosphorylated proteins, and 228 acetylated proteins in response to SAHA treatment in 5–8 F cells. In addition, we identified 46 proteins exhibiting both acetylation and phosphorylation, such as WSTF and LMNA. With the aid of intensive bioinformatics analyses, multiple cellular processes and signaling pathways involved in tumorigenesis were clustered, including glycolysis, EGFR signaling, and Myc signaling pathways. Taken together, this study highlighted the interconnectivity of acetylation and phosphorylation signaling networks and suggested that SAHA-mediated HDAC inhibition may alter both acetylation and phosphorylation of viral proteins. Subsequently, cellular signaling pathways were reprogrammed and contributed to anti-tumor effects of SAHA in NPC cells.

Suberoylanilide hydroxamic acid suppresses axonal damage and neurological dysfunction after subarachnoid hemorrhage via the HDAC1/HSP70/TDP-43 axis

Increased focus has been placed on the role of histone deacetylase inhibitors as crucial players in subarachnoid hemorrhage (SAH) progression. Therefore, this study was designed to expand the understanding of SAH by exploring the downstream mechanism of the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA) in SAH. The expression of TDP-43 in patients with SAH and rat models of SAH was measured. Then, western blot analysis, immunofluorescence staining, and transmission electron microscope were used to investigate the in vitro effect of TDP-43 on a neuronal cell model of SAH established by oxyhemoglobin treatment. Immunofluorescence staining and coimmunoprecipitation assays were conducted to explore the relationship among histone deacetylase 1 (HDAC1), heat shock protein 70 (HSP70), and TDP-43. Furthermore, the in vivo effect of HDAC1 on SAH was investigated in rat models of SAH established by endovascular perforation. High expression of TDP-43 in the cerebrospinal fluid of patients with SAH and brain tissues of rat models of SAH was observed, and TDP-43 accumulation in the cytoplasm and the formation of inclusion bodies were responsible for axonal damage, abnormal nuclear membrane morphology, and apoptosis in neurons. TDP-43 degradation was promoted by the HDAC1 inhibitor SAHA via the acetylation of HSP70, alleviating SAH, and this effect was verified in vivo in rat models. In conclusion, SAHA relieved axonal damage and neurological dysfunction after SAH via the HSP70 acetylation-induced degradation of TDP-43, highlighting a novel therapeutic target for SAH.

Suberoylanilide hydroxamic acid induced microspore embryogenesis and promoted plantlet regeneration in ornamental kale (Brassica oleracea var. acephala).

Isolated Microspore Culture (IMC) is an efficient method to obtain the homozygous strain; however, it is difficult to apply in ornamental kale due to its low rate of microspore embryogenesis. Histone acetylation is an important epigenetic mechanism and may affect the changes of the microspore development pathway, promoting microspore embryogenesis. Here, microspores from three cut-flower ornamental kales, namely Crane Feather Queen (CFQ), Crane Pink (CP), and Crane Bicolor (CB), were treated with the histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA) to induce embryogenesis. The haploid 'CFQ' microspore plantlets were doubled with colchicine. The results for 'CFQ' revealed that, the appropriate concentration of SAHA was 0.03μM and obtained 17.27 embryos per bud. For 'CP,' the appropriate concentration of SAHA was 0.045μM and obtained 11.19 embryos per bud. For 'CB,' the appropriate concentration of SAHA was 0.045μM and obtained 6.10 embryos per bud. Haploid 'CFQ' microspore plantlets were treated with 75mg/L colchicine for 7 d and the doubling rate was 41.7%. Haploid 'CFQ' plantlets were treated with 1000mg/L colchicine by root-soaking for 4h and the doubling rate was 64.3%. SAHA could promote microspore embryogenesis, and colchicine root soaking was more effective than adding colchicine to the medium for haploid plantlet doubling in cut-flower ornamental kale.

Molecular mechanisms of bifunctional vitamin D receptor agonist-histone deacetylase inhibitor hybrid molecules in triple-negative breast cancer

The active form of vitamin D, 1,25-dihydroxyvitamin D (1,25D), and its analogues signal through the nuclear vitamin D receptor (VDR), a ligand-regulated transcription factor, and have been extensively investigated as anticancer agents. 1,25D and its analogs have potential in combination therapies because they exhibit synergistic activities with other anticancer agents such as histone deacetylase inhibitors (HDACi). We have developed a series of hybrid molecules that combine HDACi within the backbone of a VDR agonist and thus represent fully integrated bifunctional molecules. They exhibit anti-tumor efficacy in reducing tumor growth and metastases in an aggressive model of triple-negative breast cancer. However, their solubility is limited by their hydrophobic diarylpentane cores. Our goals here were two-fold: (1) to improve the solubility of hybrids by introducing nitrogen into diarylpentane cores, and (2) to investigate the molecular mechanisms underlying their anti-tumor efficacy by performing comparative gene expression profiling studies with 1,25D and the potent HDACi suberoylanilide hydroxamic acid (SAHA). We found that substituting aryl with pyrydyl rings did not sacrifice bifunctionality and modestly improved solubility. Notably, one compound, AM-193, displayed enhanced potency as a VDR agonist and in cellular assays of cytotoxicity. RNAseq studies in triple negative breast cancer cells revealed that gene expression profiles of hybrids were very similar to that of 1,25D, as was that observed with 1,25D and SAHA combined. The effects of SAHA alone on gene expression were limited and distinct from those 1,25D or hybrids. The combined results suggest that efficacy of hybrids arises from targeting HDACs that do not have a direct role in gene regulation. Moreover, pathways analysis revealed that hybrids regulate numerous genes controlling immune cell infiltration into tumors and suppress the expression of several secreted molecules that promote breast cancer growth and metastasis.

Combining EGFR-TKI With SAHA Overcomes EGFR-TKI-Acquired Resistance by Reducing the Protective Autophagy in Non-Small Cell Lung Cancer.

Nowadays, lung cancer has the highest mortality worldwide. The emergence of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) has greatly improved the survival of patients with non-small cell lung cancer (NSCLC) having EGFR-TKI-sensitive mutations. Unfortunately, acquired resistance happens for most patients. In the present research, we found that EGFR-TKIs (such as gefitinib and osimertinib) can induce autophagy in NSCLC cell lines. Compared with parental sensitive cells, drug-resistant cells have higher autophagy activity. The use of an autophagy inhibitor could enhance the toxicity of gefitinib and osimertinib, which indicates that the enhancement of protective autophagy might be one of the mechanisms of EGFR-TKI resistance in NSCLC. In addition, increased autophagy activity is associated with decreased enhancer of zeste homolog 2 (EZH2) expression. Knockdown of EZH2 or EZH2 inhibitor treatment could lead to increased autophagy in NSCLC cells, indicating that EZH2 is a negative regulator of autophagy. We revealed that the increase in autophagy caused by the reduction of EZH2 was reversed in vitro and in vivo when combining gefitinib or osimertinib with suberoylanilide hydroxamic acid (SAHA), a broad-spectrum histone deacetylase inhibitor (HDACi). In conclusion, our results indicated that the combination of EGFR-TKIs and SAHA may be a new strategy to overcome EGFR-TKIs acquired resistance.

Improvement of resistance to oxaliplatin by vorinostat in human colorectal cancer cells through inhibition of Nrf2 nuclear translocation

Vorinostat (suberoylanilide hydroxamic acid: SAHA), a histone deacetylase inhibitor, has potential benefit of improving the resistance to conventional other anti-cancer drugs. This study was aimed to clarify whether SAHA improves the resistance to oxaliplatin (L-OHP), a platinum-based anticancer drug using L-OHP-resistant HCT116 cells (HCT116/OxR), established from colorectal cancer (CRC) cell line HCT116. HCT116/OxR cells showed cross-resistance to other platinum-based drugs. Pre-treatment with SAHA improved the sensitivity of both L-OHP and its metabolite in HCT116/OxR cells, but not in parental HCT116 cells. However, pre-treatment with SAHA did not affect the sensitivity of other platinum-based drugs. These results indicated that SAHA specifically improved the sensitivity of L-OHP in HCT116/OxR cells. Focusing on NF-E2 p45-related factor 2-Kelch-like ECH-associated protein 1 pathway (Nrf2-Keap1) pathway, which is activated by oxidative stress such as the treatment with anti-cancer drugs, mechanisms behind these observations were elucidated. In HCT116/OxR cells transfected with Nrf2 siRNA, the improving effects on L-OHP resistance by SAHA were abolished, suggesting that Nrf2-Keap1 pathway was involved in L-OHP-resistance. In addition, L-OHP metabolite significantly induced the expression of the nuclear protein Nrf2 and its target gene mRNA expression in HCT116/OxR cells. Pre-treatment with SAHA suppressed these changes observed in HCT116/OxR cells. In conclusion, this study demonstrated that SAHA improved L-OHP resistance by inhibiting Nrf2-Keap1 activation via Nrf2 nuclear translocation by L-OHP metabolite.

Synthesis, in vitro and structural aspects of cap substituted Suberoylanilide hydroxamic acid analogs as potential inducers of apoptosis in Glioblastoma cancer cells via HDAC /microRNA regulation

Glioblastoma multiforme (GBM) is a heterogeneous, aggressive brain cancer characterized by chemo-resistance and cancer stemness. Histone deacetylases (HDACs) are a group of enzymes that regulate chromatin epigenetics which were in turn found to be controlled by microRNAs (miRs). The drug employed in chemotherapy for the treatment of GBM is Temozolomide (TMZ). Unfortunately, many GBM patients exhibit chemo-resistance to this drug. Here we have synthesized various Suberoyl anilide hydroxamic acid (SAHA) analogs with many substitutions at the cap site majority of which not yet studied. These SAHA analogs have exhibited profound cytotoxicity at 2 μM, and 4 μM concentrations in GBM cancer cell line U87MG, and 1 μM, and 2 μM concentrations in breast cancer cell line MCF-7. Surprisingly, these analogs have exhibited cytotoxic effects in chronic lymphoid leukemia cells (Raji) at 64 μM, and 128 μM concentrations due to mutated p53. Among all the synthesized analogs 3-Chloro-SAHA, 3-Chloro-4-fluoro SAHA have exhibited effective cytotoxicity in all cancer cells. These potent analogs inhibited HDAC-8 enzyme activity by 2-folds in U87MG, and MCF-7 cell lines and 7-folds decrease in HDAC-8 activity was observed in Raji cell line. These analogs decreased the expression of HDAC-2, HDAC-3 genes and enhanced the expression of p53 tumor suppressor. Interestingly, these compounds decreased the expression of Rictor, the main component of the mTORC2 complex involved cancer cell metabolism. Furthermore, these molecules have decreased oncogenic microRNA expression such as miR-21 and enhanced the expression of tumor suppressor microRNAs such as miR-143. The HDAC binding ability of these molecules was highly significant and have exhibited the ability to cross blood-brain barrier (BBB), and followed the Lipinski rule of five. Thus, these molecules need to be taken up further to clinics for better therapy against GBM either singly or combination therapy.

Novel Suberoylanilide Hydroxamic Acid Analogs Inhibit Angiogenesis and Induce Apoptosis in Breast Cancer Cells.

Histone deacetylases (HDACs) are the enzymes that catalyze the removal of the acetyl group from lysine residues and regulate several biological processes. Suberoylanilide hydroxamic acid (SAHA) is a notable HDAC inhibitor that exhibited remarkable anti-proliferative efficiency by alleviating gene regulation against solid and hematologic cancers. The aim of this study was to develop new chemotherapeutic agents for breast cancer treatment, therefore, a novel series of Suberoylanilide hydroxamic acid (SAHA) analogs were investigated as anticancer agents. We designed and synthesized a novel series of analogs derived from SAHA by substituting alkyl, alkoxy, halo, and benzyl groups at different positions of the phenyl ring. The newly synthesized analogs were assessed for their cytotoxic potential against four human cancer cell lines in comparison with healthy cell lines, using several biological assays. SAHA analogs displayed significant cytotoxic potential with IC50 values ranging from 1.6 to 19.2 μM in various tumor cell lines. Among these analogs, 2d (containing 3-chloro, 4-floro substitutions on phenyl moiety), 2h (containing 3,4-di chloro substitutions on phenyl moiety), and 2j (containing 4-chloro, 3-methyl substitutions on phenyl moiety) showed significant cytotoxic potential with IC50 values ranging from 1.6 to 1.8 μM in MCF-7 (breast carcinoma) cell line. More importantly, these analogs were found to be non-toxic towards healthy primary human hepatocytes (PHH) and mouse fibroblast cells (NIH3T3), which represent their tumor selectivity. These analogs were further analyzed for their effect on cell migration, BrdU incorporation, Annexin V-FITC and cell cycle arrest (Sub-G1 phase). Remarkably, analogs 2d, 2h, and 2j displayed significant HDAC inhibition than the parent SAHA molecule. Further studies also confirmed that these SAHA analogs are efficient in inducing apoptosis, as they regulated the expression of several proteins involved in mitochondrial or intrinsic apoptosis pathways. Findings in the Chick Chorioallantoic Membrane (CAM) assay studies revealed anti-angiogenic properties of the currently described SAHA analogs. From anti-proliferative study results, it is clearly evident that 3,4-substitution at the SAHA phenyl ring improves the anti-proliferative activity of SAHA. Based on these findings, we presume that the synthesized novel SAHA analogs could be potential therapeutic agents in treating breast cancer.

SAHA Alleviates Diarrhea-Predominant Irritable Bowel Syndrome Through Regulation of the p-STAT3/SERT/5-HT Signaling Pathway.

ObjectiveIrritable bowel syndrome (IBS) is characterized by abdominal pain, bloating, and stool irregularity. However, its pathophysiological mechanisms, which trigger intestinal motility disorders and diarrhea leading to diarrhea-predominant IBS (D-IBS), remain largely unknown.MethodsIn the present study, we established a D-IBS rat model by mother–infant separation combined with restraint stress. Then we exposed the modelled rats to suberoylanilide hydroxamic acid (SAHA) treatment, followed by determination of their visceral sensitivity. Toluidine blue staining served to reveal the effects of SAHA treatment on mast cells of D-IBS model rats. Then we measured the expression of serotonin (5-hydroxytryptamine; 5-HT) and its receptors by ELISA.ResultsConstruction of short hairpin RNA (sh)-serotonin transporter (SERT) lentivirus vectors verified the regulation of the 5-HT signaling pathway by phosphorylated (p)-STAT/SERT. SAHA treatment of D-IBS model rats reduced the fecal water content, electromyography integral change rate, abdominal withdrawal reflex score, and number of mast cells, as well as the expression of 5-HT type 3A (5-HT3AR), 3B receptor (5-HT3BR), and 4 receptor (5-HT4R) receptors. The treatment also elevated the expression of signal transducer and activator for transcription 3 (STAT3) and SERT. Activation of p-STAT3 may reverse the inhibitory effect of SAHA on the elevated visceral sensitivity of D-IBS model rats. Moreover, SAHA promoted the transcription of SERT through repression of the p-STAT3/5-HT signaling, thereby inhibiting the visceral sensitivity of D-IBS model rats.ConclusionThis study highlights that SAHA treatment can alleviate D-IBS through regulation of the p-STAT3/SERT/5-HT signaling pathway.

LPS-induced lipid alterations in microglia revealed by MALDI mass spectrometry-based cell fingerprinting in neuroinflammation studies

Pathological microglia activation can promote neuroinflammation in many neurodegenerative diseases, and it has therefore emerged as a potential therapeutic target. Increasing evidence suggests alterations in lipid metabolism as modulators and indicators in microglia activation and its effector functions. Yet, how lipid dynamics in activated microglia is affected by inflammatory stimuli demands additional investigation to allow development of more effective therapies. Here, we report an extensive matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) whole cell fingerprinting workflow to investigate inflammation-associated lipid patterns in SIM-A9 microglial cells. By combining a platform of three synergistic MALDI MS technologies we could detect substantial differences in lipid profiles of lipopolysaccharide (LPS)- stimulated and unstimulated microglia-like cells leading to the identification of 21 potential inflammation-associated lipid markers. LPS-induced lipids in SIM-A9 microglial cells include phosphatidylcholines, lysophosphatidylcholines (LysoPC), sphingolipids, diacylglycerols and triacylglycerols. Moreover, MALDI MS-based cell lipid fingerprinting of LPS-stimulated SIM-A9 microglial cells pre-treated with the non-selective histone deacetylase inhibitor suberoylanilide hydroxamic acid revealed specific modulation of LPS-induced-glycerolipids and LysoPC(18:0) with a significant reduction of microglial inflammation response. Our study introduces MALDI MS as a complementary technology for fast and label-free investigation of stimulus-dependent changes in lipid patterns and their modulation by pharmaceutical agents.

Induction of funitatin A, a new polyketide from the Yellow River wetland-derived fungus Talaromyces funiculosus

• A novel polyketide was isolated from fungus Talaromyces funiculosus by adding the HDAC inhibitor SAHA. • The structure of the new compound was determined by analysis of 1D and 2D NMR and HRESIMS spectra. • The new compound was the first microbial natural product bearing a rare dimeric cyclopaldic acid structure. • The new compound showed moderate antimicrobial activity against the Proteus species and Escherichia coli . A new, highly modified fatty acid ester, funitatin A ( 1 ), was isolated from the Yellow River wetland-derived fungus Talaromyces funiculosus HPU-Y01 cultivated with the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA). The structure of 1 was established by analysis of NMR and HRESIMS data. Compound 1 featured a rare dimeric cyclopaldic acid structure and showed promising antimicrobial activity against both Proteus species and Escherichia coli with MIC values of 3.13 μM.

SAHA Inhibits Somatic Hyperalgesia Induced by Stress Combined with Orofacial Inflammation Through Targeting Different Spinal 5-HT Receptor Subtypes.

Epigenetic regulation of gene expression has been implicated in the development of chronic pain. However, little is known about whether this regulation is involved in the development and treatment of chronic pain comorbidities such as fibromyalgia syndrome (FMS) and temporomandibular disorder (TMD), a comorbidity predominantly occurring among women. Here we explored the impact of the histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA) on somatic hyperalgesia induced by stress or stress combined with orofacial inflammation, which mimicked the comorbidity of FMS and TMD in rats. Our data showed that somatic thermal hyperalgesia and mechanical allodynia induced by both conditions were completely prevented by intrathecal injection of SAHA, which upregulated 5-HT2C receptors but downregulated 5-HT3 receptors in the spinal dorsal horn. Subsequent spinal administration of RS102221 to inhibit 5-HT2C receptors or SR57227 to activate 5-HT3 receptors reversed the analgesic effect of SAHA under both conditions. These results indicate that SAHA attenuates the pro-nociceptive effects of stress combined with orofacial inflammation and the effects of stress alone. This likely occurs through epigenetic regulation of spinal 5-HT2C and 5-HT3 receptor expression, suggesting that SAHA has potential therapeutic value in FMS or comorbid FMS-TMD patients with somatic hyperalgesia.

Regulation of Opsin Gene Expression by DNA Methylation and Histone Acetylation.

One important role of epigenetic regulation is controlling gene expression in development and homeostasis. However, little is known about epigenetics’ role in regulating opsin expression. Cell cultures (HEK 293, Y79, and WERI) producing different levels of opsins were treated with 5-aza-2’-deoxycytidine (5-Aza-dc) and/or sodium butyrate (SB) or suberoylanilide hydroxamic acid (SAHA) for 72 h. Global DNA methylation, site-specific methylation, and expressions of opsins were measured by LUMA assay, bisulfite pyrosequencing, and qPCR, respectively. Mouse retinal explants from wild-type P0/P1 pups were ex vivo cultured with/without 5-Aza-dc or SAHA for 6 days. The morphology of explants, DNA methylation, and expressions of opsins was examined. The drugs induced global DNA hypomethylation or increased histone acetylation in cells, including DNA hypomethylation of rhodopsin (RHO) and L-opsin (OPN1LW) and a concomitant increase in their expression. Further upregulation of RHO and/or OPN1LW in HEK 293 or WERI cells was observed with 5-Aza-dc and either SB or SAHA combination treatment. Mouse retinal explants developed normally but had drug-dependent differential DNA methylation and expression patterns of opsins. DNA methylation and histone acetylation directly regulate opsin expression both in vitro and ex vivo. The ability to manipulate opsin expression using epigenetic modifiers enables further study into the role of epigenetics in eye development and disease.

The anti-inflammatory mechanism of SAHA in acute pancreatitis through HDAC5/SLIT2/Akt/β-catenin axis.

Acute pancreatitis (AP) is widely recognized to be an inflammation-related disease, in which HDAC was upregulated. The anti-inflammatory role of suberoylanilide hydroxamic acid (SAHA), a HDAC inhibitor, has been documented. In this context, this research was implemented to figure out whether SAHA manipulated inflammation in AP. Subsequent to induction of AP mouse model, HDAC5 expression was detected. The binding of HDAC5 and SLIT2 was detected by Co-Immunoprecipitation and Chromatin immunoprecipitation assays. SAHA treatment and gain- and loss-of-function approaches were used in AP mice and lipopolysaccharide (LPS)-induced pancreatic acinar cells. In mice, biochemical methods were implemented to measure activities of pancreatic lipase, trypsin, myeloperoxidase (MPO) and pancreatic edema, TUNEL staining to determine pancreatic cell apoptosis, and flow cytometry to assess the total number of leukocytes and neutrophils in pancreas. In pancreatic acinar cells, CCK-8 was performed to evaluate cell viability. HDAC5 exhibited overexpression in AP mice. Mechanical analysis showed that HDAC5 facilitated SLIT2 deacetylation to downregulate SLIT2, thus activating Akt/β-catenin pathway in pancreatic acinar cells. SAHA treatment, HDAC5 silencing or SLIT2 overexpression diminished inflammation in AP in vivo and in vitro. SAHA treatment, HDAC5 silencing or SLIT2 overexpression reduced activities of pancreatic lipase, trypsin, MPO, pancreatic edema and cell apoptosis in AP mice as well as elevated viability of LPS-induced pancreatic acinar cells. SAHA might exert anti-inflammatory effects in AP mice via HDAC5/SLIT2/Akt/β-catenin axis.

Histone Acetylation Defects in Brain Precursor Cells: A Potential Pathogenic Mechanism Causing Proliferation and Differentiation Dysfunctions in Mitochondrial Aspartate-Glutamate Carrier Isoform 1 Deficiency.

Mitochondrial aspartate-glutamate carrier isoform 1 (AGC1) deficiency is an ultra-rare genetic disease characterized by global hypomyelination and brain atrophy, caused by mutations in the SLC25A12 gene leading to a reduction in AGC1 activity. In both neuronal precursor cells and oligodendrocytes precursor cells (NPCs and OPCs), the AGC1 determines reduced proliferation with an accelerated differentiation of OPCs, both associated with gene expression dysregulation. Epigenetic regulation of gene expression through histone acetylation plays a crucial role in the proliferation/differentiation of both NPCs and OPCs and is modulated by mitochondrial metabolism. In AGC1 deficiency models, both OPCs and NPCs show an altered expression of transcription factors involved in the proliferation/differentiation of brain precursor cells (BPCs) as well as a reduction in histone acetylation with a parallel alteration in the expression and activity of histone acetyltransferases (HATs) and histone deacetylases (HDACs). In this study, histone acetylation dysfunctions have been dissected in in vitro models of AGC1 deficiency OPCs (Oli-Neu cells) and NPCs (neurospheres), in physiological conditions and following pharmacological treatments. The inhibition of HATs by curcumin arrests the proliferation of OPCs leading to their differentiation, while the inhibition of HDACs by suberanilohydroxamic acid (SAHA) has only a limited effect on proliferation, but it significantly stimulates the differentiation of OPCs. In NPCs, both treatments determine an alteration in the commitment toward glial cells. These data contribute to clarifying the molecular and epigenetic mechanisms regulating the proliferation/differentiation of OPCs and NPCs. This will help to identify potential targets for new therapeutic approaches that are able to increase the OPCs pool and to sustain their differentiation toward oligodendrocytes and to myelination/remyelination processes in AGC1 deficiency, as well as in other white matter neuropathologies.

Glycocalyx mechanotransduction mechanisms are involved in renal cancer metastasis

Mammalian cells, including cancer cells, are covered by a surface layer containing cell bound proteoglycans, glycoproteins, associated glycosaminoglycans and bound proteins that is commonly referred to as the glycocalyx. Solid tumors also have a dynamic fluid microenvironment with elevated interstitial flow. In the present work we further investigate the hypothesis that interstitial flow is sensed by the tumor glycocalyx leading to activation of cell motility and metastasis. Using a highly metastatic renal carcinoma cell line (SN12L1) and its low metastatic counterpart (SN12C) we demonstrate in vitro that the small molecule Suberoylanilide Hydroxamic Acid (SAHA) inhibits the heparan sulfate synthesis enzyme N-deacetylase-N-sulfotransferase-1, reduces heparan sulfate in the glycocalyx and suppresses SN12L1 motility in response to interstitial flow. SN12L1 cells implanted in the kidney capsule of SCID mice formed large primary tumors and metastasized to distant organs, but when treated with SAHA metastases were not detected. In another set of experiments, the role of hyaluronic acid was investigated. Hyaluronan synthase 1, a critical enzyme in the synthetic pathway for hyaluronic acid, was knocked down in SN12L1 cells and in vitro experiments revealed inhibition of interstitial flow induced migration. Subsequently these cells were implanted in mouse kidneys and no distant metastases were detected. These findings suggest new therapeutic approaches to the treatment of kidney carcinoma metastasis.

Histone deacetylase inhibitors attenuated interleukin-1β-induced chondrogenesis inhibition in synovium-derived mesenchymal stem cells of the temporomandibular joint.

AimsIn the repair of condylar cartilage injury, synovium-derived mesenchymal stem cells (SMSCs) migrate to an injured site and differentiate into cartilage. This study aimed to confirm that histone deacetylase (HDAC) inhibitors, which alleviate arthritis, can improve chondrogenesis inhibited by IL-1β, and to explore its mechanism.MethodsSMSCs were isolated from synovium specimens of patients undergoing temporomandibular joint (TMJ) surgery. Chondrogenic differentiation potential of SMSCs was evaluated in vitro in the control, IL-1β stimulation, and IL-1β stimulation with HDAC inhibitors groups. The effect of HDAC inhibitors on the synovium and condylar cartilage in a rat TMJ arthritis model was evaluated.ResultsInterleukin (IL)-1β inhibited the chondrogenic differentiation potential of SMSCs, while the HDAC inhibitors, suberoylanilide hydroxamic acid (SAHA) and panobinostat (LBH589), attenuated inhibition of IL-1β-induced SMSC chondrogenesis. Additionally, SAHA attenuated the destruction of condylar cartilage in rat TMJ arthritis model. IL-6 (p < 0.001) and matrix metalloproteinase 13 (MMP13) (p = 0.006) were significantly upregulated after IL-1β stimulation, while SAHA and LBH589 attenuated IL-6 and MMP13 expression, which was upregulated by IL-1β in vitro. Silencing of IL-6 significantly downregulated MMP13 expression and attenuated IL-1β-induced chondrogenesis inhibition of SMSCs.ConclusionHDAC inhibitors SAHA and LBH589 attenuated chondrogenesis inhibition of SMSC induced by IL-1β in TMJ, and inhibition of IL-6/MMP13 pathway activation contributes to this biological progress. This study provides a theoretical basis for the application of HDAC inhibitors in the treatment of TMJ arthritis.Cite this article: Bone Joint Res 2022;11(1):40–48.

Suberoylanilide Hydroxamic Acid (SAHA) Reduces Glutamate-Induced Oxidative Stress in Hippocampal Cells

Suberoylanilide Hydroxamic Acid (SAHA) Reduces Glutamate-Induced Oxidative Stress in Hippocampal Cells

Histone Deacetylase Inhibitors (HDACi) Promote KLF5 Ubiquitination and Degradation in Basal-like Breast Cancer.

Basal-like breast cancer (BLBC) accounts for approximately 15% of all breast cancer cases, and patients with BLBC have a low survival rate. Our previous study demonstrated that the KLF5 transcription factor promotes BLBC cell proliferation and tumor growth. In this study, we demonstrated that the histone deacetylase inhibitors (HDACi), suberoylanilide hydroxamic acid (SAHA), and trichostatin A (TSA), increased KLF5 acetylation at lysine 369 (K369), downregulated KLF5 protein expression levels, and decreased cell viability in BLBC cell lines. HDACi target KLF5 for proteasomal degradation by promoting KLF5 protein ubiquitination. K369 acetylation of KLF5 decreases the binding between KLF5 and its deubiquitinase, BAP1. These findings revealed a novel mechanism by which HDACi suppress BLBC, and a novel crosstalk between KLF5 protein acetylation and ubiquitination.

Molecular and Thermodynamic Modeling of the Protein-Ligand Interaction. Application to Computer-Assisted Design of Anti-Competitive Inhibitors of Human Histone Deacetylase 2 (HDAC2)

Background: Histone deacetylases (HDACs) are promising drug targets for a variety of therapeutic applications. Here we report in silico design and evaluation of novel amine-based hydroxamic acid derivatives (DAHAs), HDAC2 inhibitors with favorable predicted pharmacokinetic profiles. Methods: By using in situ modifications of the crystal structure of suberoylanilide hydroxamic acid SAHA-HDAC2 complex (PDB entry 4LXZ), 3D models of HDAC2-DAHAx complexes were prepared for a training set of 18 DAHAs with experimentally determined inhibitory potencies (half-maximal inhibitory concentrations IC50exp In the search for active conformations of the DAHA1-18, a linear QSAR model was prepared, which correlated computed gas-phase enthalpies of formation (∆∆HMM) of HDAC2-DAHAx complexes with the IC50exp. Further, taking into account the solvent effect and entropy changes upon ligand, binding resulted in a superior QSAR model correlating computed complexation Gibbs free energies (∆∆Gcom). The successive pharmacophore model (PH4) generated from the active conformations of DAHAs served as a virtual screening tool of novel analogs included in a virtual combinatorial library (VCL) of compounds containing hydroxamic acid scaffolds. The PH4 model to identify new DAHA analogs screened the VCL filtered by Lipinski’s rule-of-five. Results: Gas-phase QSAR model: -log10(IC50exp) = pIC50exp -0.2870 x ∆∆HMM +6.5764, R2= 0.83, superior aqueous phase QSAR model: pIC50exp =-0.4005 x ∆∆Gcom + 6.4402, R2=0.93 and PH4 pharmacophore model : pIC50exp = 1.0107 x pIC50pre - 0.0607, R2 = 0.92. The VCL of more than 198 thousand DAHAs was filtered down to 150,713 analogs Lipinski’s rule. The PH4 screening retained 110 new and potent DAHAs with predicted inhibitory potencies pIC50pre up to 520-fold lower than .that of DAHA1 (IC50exp =260nM). Predicted pharmacokinetic profiles of the new analogs were compared to current per oral anti-cancer drugs. Conclusions: This computational approach, which combines molecular modeling, pharmacophore model, analysis of HDAC2-DAHAs interaction energies, in silico screening of VCL of DAHAs, and ADME properties resulted in a set of proposed new HDAC2 inhibitors.