Role Of HDACs Research Articles

A novel potent class I HDAC inhibitor reverses the STAT4/p66Shc apoptotic defect in B cells from chronic lymphocytic leukemia patients

Chronic Lymphocytic Leukemia (CLL) patients have a defective expression of the proapoptotic protein p66Shc and of its transcriptional factor STAT4, which evoke molecular abnormalities, impairing apoptosis and worsening disease prognosis and severity. p66Shc expression is epigenetically controlled and transcriptionally modulated by STAT4; epigenetic modifiers are deregulated in CLL cells and specific histone deacetylases (HDACs) like HDAC1, are overexpressed. Reactivation of STAT4/p66Shc expression may represent an attractive and challenging strategy to reverse CLL apoptosis defects. New selective class I HDAC inhibitors (HDACis, 6a-g) were developed with increased potency over existing agents and preferentially interfering with the CLL-relevant isoform HDAC1, to unveil the role of class I HDACs in the upregulation of STAT4 expression, which upregulates p66Shc expression and hence normalizes CLL cell apoptosis. 6c (chlopynostat) was identified as a potent HDAC1i with a superior profile over entinostat. 6c induces marked apoptosis of CLL cells compared with SAHA, which was associated with an upregulation of STAT4/p66Shc protein expression. The role of HDAC1, but not HDAC3, in the epigenetic upregulation of STAT4/p66Shc was demonstrated for the first time in CLL cells and was validated in siRNA-induced HDAC1/HDAC3 knock-down EBV-B cells. To sum up, HDAC1 inhibition is necessary to reactivate STAT4/p66Shc expression in patients with CLL. 6c is one of the most potent HDAC1is known to date and represents a novel pharmacological tool for reversing the impairment of the STAT4/p66Shc apoptotic machinery.

Intestinal-specific Hdac3 deletion increases susceptibility to colitis and small intestinal tumour development in mice fed a high fat diet.

High fat diets, and inflammation are risk factors for colon cancer, however the underlying mechanisms remain to be fully elucidated. The transcriptional co-repressor HDAC3 has recently emerged as a key regulator of intestinal epithelial responses to diet and inflammation with intestinal-specific Hdac3 deletion (Hdac3IKO) in mice increasing lipid oxidation genes and the rate of lipid oxidation in enterocytes. Hdac3IKO mice are also predisposed to experimentally induced colitis, however whether this is driven by the intestinal metabolic reprogramming, and whether this predisposes these mice to intestinal tumourigenesis is unknown. Herein, we examined the effects of intestinal-specific Hdac3 deletion on colitis-associated intestinal tumourigenesis in mice fed a standard (STD) or HF diet (HFD). Hdac3IKO mice were highly prone to experimentally induced colitis, which was further enhanced by a HFD. Hdac3deletion also accelerated intestinal tumour development, specifically when fed a HFD and most notably in the small intestine where lipid absorption is maximal. Expression of proteins involved in fatty acid metabolism and oxidation (SCD1, EHHADH) were elevated in the small intestine of Hdac3IKO mice fed a HFD, and these mice displayed increased levels of lipid peroxidation, DNA damage, and apoptosis in their villi, as well as extensive expansion of the stem cell and progenitor cell compartment. These findings reveal a novel role for Hdac3 in suppressing colitis and intestinal tumorigenesis, particularly in the context of consumption of a HFD, and reveal a potential mechanism by which HFDs may increase intestinal tumorigenesis by increasing lipid oxidation, DNA damage and intestinal epithelial cell turnover.

Single Inhibitors versus Dual Inhibitors: Role of HDAC in Cancer.

Due to the multimodal character of cancer, inhibition of two targets simultaneously by a single molecule is a beneficial and effective approach against cancer. Histone deacetylase (HDAC) was widely investigated as a novel category of anticancer drug targets due to its crucial role in various biological processes like cell-proliferation, metastasis, and apoptosis. Numerous HDAC inhibitors such as vorinostat and panobinostat are clinically approved but have limited usage due to their low efficacy, nonselectivity, drug resistance, and toxicity. Therefore, HDACs with a dual targeting ability have attracted great attention. The strategy of combining a HDAC inhibitor with other antitumor agents has been proved advantageous for combating the nonselectivity and drug resistivity problems associated with single-target drugs. Henceforth, we have highlighted dual-targeting inhibitors to target HDAC along with topoisomerase, receptor tyrosine kinase inhibitors, and the zeste homolog 2 enzyme. Our Review mainly focuses on the impact of the substituent effect along with the linker variation of well-known HDAC-inhibitor-conjugated anticancer drugs.

Role of HDAC in Mediating Homeostasis in Plants during Stress - A Review

Role of HDAC in Mediating Homeostasis in Plants during Stress - A Review

Evaluation of High-Dose Cytarabine Induction Therapy and Flow Cytometric Measurable Residual Disease Monitoring for Children with De Novo Acute Myeloid Leukemia: A Report from the JPLSG-AML-12 Trial

Background: High-dose cytarabine (HDAC) in initial induction therapy has been tested in several clinical trials both in children and adults with acute myeloid leukemia (AML), however, the trial results are conflicting. In addition, there is growing evidence on significance of measurable residual disease (MRD) monitoring to predict subsequent relapse, but MRD in AML is still challenging in terms of methodology and quality control. In the nationwide clinical trial AML-12 by the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG), the hematological malignancy subgroup of the Japan Children's Cancer Group (JCCG), a role of HDAC in initial induction and feasibility and efficacy of central reference laboratory-based flow cytometric MRD (FCM-MRD) monitoring were evaluated in children with AML. Patients & Methods: JPLSG-AML-12 trial (registered as jRCTs041180128) was designed as a seamless phase II/III trial; because of a safety concern in HDAC induction, children (0-18 years old) with newly diagnosed de novo AML (excluding acute promyelocytic leukemia and AML in Down syndrome patients) registered in selected institutions were randomized to receive either standard ECM (etoposide, standard-dose cytarabine, and mitoxantrone) or experimental HD-ECM (etoposide, HDAC, and mitoxantrone) induction, while patients registered in non-selected institutions were non-randomly allocated to receive standard ECM; in the following phase III part, all the patients were randomized. FCM-MRD were measured at two time points [end of Induction-1 (EOI-1) and end of Induction-2 (EOI-2)] at either of the two central reference laboratories (Mie University or Kyoto University) but was not used to guide subsequent therapies. Following complete remission (CR) evaluation at EOI-2, patients achieving CR were allocated to either of the 3 risk groups and received post-remission chemotherapies; core-binding-factor standard risk (CBF SR), non-CBF SR, or high risk (HR) group. Only HR patients were allocated to receive allogeneic hematopoietic stem cell transplantation in first CR. Primary endpoints of the trial were 3-year EFS and positive FCM-MRD (≥0.1%) rate at EOI-1. Results: Total 359 eligible patients were registered at 102 institutions between 2014-2018. CR, 3-year EFS, and 3-year OS rates of all patients were 94.0%, 63.1% (95%CI, 57.9-67.9%), and 80.3% (95%CI, 75.8-84.1%), respectively. Among all, 324 patients were randomized (ECM, n=168; HD-ECM, n=156). Median follow-up period of these patients was 50.9 months (range, 0.2 - 84.7 months). No significant difference in outcomes were observed between the 2 arms; CR rates were 94.2% vs. 93.8% (p=0.998), 3-year EFS rates were 64.3% (95%CI, 56.5-71.0%) vs. 61.2% (53.1-68.4%) (p=0.551), 3-year OS rates were 84.4% (95%CI, 78.0-89.1%) vs. 75.3% (95%CI, 67.7-81.4%) (p=0.053), 3-year cumulative incidence of relapse were 28.6% (95%CI, 21.5-36.0%) vs. 30.9% (95%CI, 23.3-38.8%) (p=0.585), and 3-year non-relapse mortality rates were 0.9% (95%CI, 0.1-6.4%) vs. 1.8% (95%CI, 0.4-7.1%) (p=0.832). These outcome parameters were not different within each risk groups as well. FCM-MRD at EOI-1 was evaluated in 135 patients (80.4%) in the ECM arm and 127 patients (81.4%) in the HD-ECM arm; the positive FCM-MRD rates were 21.5% vs. 25.2% (p=0.575). Regarding grade 3 or higher adverse events (AEs) evaluated by CTCAE version 4 during Induction-1, disseminated intravascular coagulation was more frequent in the HD-ECM arm (1.8% vs. 6.4%, p=0.046), but no significant difference was observed for other AEs. Univariable Cox regression analysis for baseline characteristics revealed that the intermediate-risk cytogenetics and positive FLT3-ITD were significantly associated with decreased EFS rate. However, in multivariable analyses for EFS after EOI-1 and EOI-2, FCM-MRD was the sole poor prognostic factor; hazard ratios were 5.24 (95%CI, 3.19-8.63) (p<0.001) at EOI-1 and 5.56 (95%CI, 2.93-10.54) (p<0.001) at EOI-2. Conclusions: Although HDAC in initial induction did not improve the outcome of children with AML, overall outcomes were comparable to the recently completed pediatric AML trials worldwide. Central reference laboratory-based FCM-MRD measurement was feasible and MRD at both EOI-1 and EOI-2 were the most powerful prognostic factors to predict outcome of children with AML. Therefore, FCM-MRD should be included in future risk stratification for children with AML. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Abstract LB566: Class 1 HDAC inhibition induces antitumor immunity by NF-kB-mediated enhanced metabolic fitness and generation of unique effector function enriched memory CD8 T cell subtype

Abstract Histone/protein deacetylases (HDACs) are a class of enzymes that regulate gene expression and are involved in regulating the transcription process as well as regulating fundamental cellular processes such as proliferation, differentiation and development. Class I HDACs (which includes HDAC1, 2, 3, and 8) contribute in epigenetic regulations of T cell tolerance. Under anergic T cell condition, HDAC1 and HDAC2 are involved in the histone deacetylation. However, the role of HDACs in CD8 T cell function and differentiation is not well understood. Therefore, we aimed to understand the effect of HDAC inhibition (HDACi) on CD8 T cells phenotype and functionality by using Entinostat (ENT), a class I HDAC (HDAC1 and 3) inhibitor. We found that ENT induces strong immune-mediated anti-tumor effects in TC-1 and B16 tumor-bearing mice. Mechanistically, ENT modulated the tumor microenvironment through an increased infiltration of CD8 T cells, enhanced CD8 T cell antigen-specificity and CD8 T cell functionality represented by interferon gamma (IFN-γ) and granzyme B (GrB) secretion. Our in vitro and in vivo data also indicate that ENT enhances central memory phenotype (CD62L+, CD44+) of CD8 T cells. We also found that ENT-treated CD8 T cells have distinct metabolic phenotype compared to activated CD8 T cells. Specifically, these cells relied more on amino acid metabolism while, unexpectedly, they had lower fatty acid uptake with enhanced mitochondrial potential (TMRM). Interestingly, ENT-induced central memory CD8 T cells also showed increased mitochondrial potential as well as reliance on amino acid metabolism. Therefore, ENT treatment induced memory cells with a unique phenotype different from the classical memory CD8 T cells with enhanced effector functions and reliance on distinct metabolic pathways. Furthermore, ENT-treated CD8 T cells have higher peaks at H3K27Ac site compared to the control. Since these peaks are mostly associated with genes such as IFN-γ, GrB, Pim1, EOMES, and IL-2, the known canonical target genes of NF-κB in CD8 T cells, we further dissected the role of NF-κB in these ENT-mediated effects. First, motif analysis showed that NF-κB binding motif is enriched in differential H3K27Ac sites associated with HDACi. Next, flow cytometry and immunofluorescence analysis showed that although ENT does not increase total NF-κB levels in CD8 T cells, it enhances its binding to the chromatin due to enhanced gene accessibility. This research highlights the significance of epigenetic modulation in enhancing the immune-mediated anti-tumor effects and provide fundamental understanding of the mechanism of action of HDAC inhibition in CD8 T cells. Citation Format: Nour Shobaki, Pankaj Gaur, Rahul Nadre, Vivek Verma, Peter Ordentlich, Lei Wang, Nazli Jafarzadeh, Wael Traboulsi, Mikayel Mkrtichyan, Seema Gupta, Samir N. Khleif. Class 1 HDAC inhibition induces antitumor immunity by NF-kB-mediated enhanced metabolic fitness and generation of unique effector function enriched memory CD8 T cell subtype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB566.

Abstract 2607: Inhibition of HDAC3 induces BRCAness and potent synergy with PARP inhibition in neuroendocrine prostate and small cell lung cancers

Abstract HDAC3 is essential for transcriptional repression and is required for the activity of NCOR1 &amp; SMRT co-repressors complexes. Inhibition of HDAC3 results in the suppression of genes responsible for DNA damage repair and maintenance of genomic stability. HDAC3/NCOR1 also play critical roles in tumor metabolism and immune cell biology. GB-3103 is a novel and potent inhibitor of HDAC3 with an IC50 of 0.56nM that was tested for activity against human neuroendocrine prostate (NEPC) and small cell lung cancers (SCLC). RNA-seq analysis of GB-3103 treated human tumor cells revealed induction of BRCAness, inhibition of genes from DNA repair pathways and inhibition of PI3K-AKT1, MYC and p53 signaling. GB-3103 showed potent in vitro anticancer activity against the human H660 NEPC line, with an IC50 of 28nM, and 21nM against the murine PNEC30 line and potent IC50 of 16nM against NCI-H209 human lung neuroendocrine cancer. Because of the potent induction of BRCAness we used zero interaction potency (ZIP) model to test the activity of the combination of GB-3103 with a PARP inhibitor against human H660 and murine PNEC30 cell lines. These experiments revealed synergy for the combination of PARPi with GB-3103 in NEPC. GB-3103 was subsequently tested alone and in combination with olaparib in a xenograft model of H660. GB3103 (TGI=3%) showed minimal activity at the selected dose against H660 compared to single agent olaparib (TGI=67%). However, when combined with olaparib, GB-3103 revealed potent synergy (TGI=96%, p&amp;lt;0.01). In the NCI-H209 human lung neuroendocrine xenograft model, GB-3103 showed robust activity as a single agent (TGI=83%) compared to single agent olaparib (TGI=33%) and single agent talazoparib (TGI=69%). When combined with olaparib, GB-3103 induced synergistic antitumor effect (TGI=99%, p&amp;lt;t0.001) when compared to olaparib treatment alone. When combined with talazoparib, GB-3103 induced synergistic antitumor effect (TGI &amp;gt;100%, p&amp;lt;0.001) when compared to talazoparib treatment alone. Taken together, these data confirm the important role of HDAC3 in neuroendocrine prostate and small cell lung cancers and suggest HDAC3 inhibition by GB-3103 could be an effective approach for patients with neuroendocrine cancers particularly when combined with inhibitors of PARP. Citation Format: Stephanie Nagl, Kendra Devore, Gregg Hirschfeld, Kari Kotlarczyk, Damaris Diaz, Tong Wang, Maggie Murray, Paul Gonzales, Stephen Thomas Gately. Inhibition of HDAC3 induces BRCAness and potent synergy with PARP inhibition in neuroendocrine prostate and small cell lung cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2607.

Histone deacetylase 1 controls cardiomyocyte proliferation during embryonic heart development and cardiac regeneration in zebrafish.

In contrast to mammals, the zebrafish maintains its cardiomyocyte proliferation capacity throughout adulthood. However, neither the molecular mechanisms that orchestrate the proliferation of cardiomyocytes during developmental heart growth nor in the context of regeneration in the adult are sufficiently defined yet. We identified in a forward genetic N-ethyl-N-nitrosourea (ENU) mutagenesis screen the recessive, embryonic-lethal zebrafish mutant baldrian (bal), which shows severely impaired developmental heart growth due to diminished cardiomyocyte proliferation. By positional cloning, we identified a missense mutation in the zebrafish histone deacetylase 1 (hdac1) gene leading to severe protein instability and the loss of Hdac1 function in vivo. Hdac1 inhibition significantly reduces cardiomyocyte proliferation, indicating a role of Hdac1 during developmental heart growth in zebrafish. To evaluate whether developmental and regenerative Hdac1-associated mechanisms of cardiomyocyte proliferation are conserved, we analyzed regenerative cardiomyocyte proliferation after Hdac1 inhibition at the wound border zone in cryoinjured adult zebrafish hearts and we found that Hdac1 is also essential to orchestrate regenerative cardiomyocyte proliferation in the adult vertebrate heart. In summary, our findings suggest an important and conserved role of Histone deacetylase 1 (Hdac1) in developmental and adult regenerative cardiomyocyte proliferation in the vertebrate heart.

The Role of Histone Deacetylase 3 Complex in Nuclear Hormone Receptor Action.

Nuclear hormone receptors (NRs) regulate transcription of the target genes in a ligand-dependent manner in either a positive or negative direction, depending on the case. Deacetylation of histone tails is associated with transcriptional repression. A nuclear receptor corepressor (N-CoR) and a silencing mediator for retinoid and thyroid hormone receptors (SMRT) are the main corepressors responsible for gene suppression mediated by NRs. Among numerous histone deacetylases (HDACs), HDAC3 is the core component of the N-CoR/SMRT complex, and plays a central role in NR-dependent repression. Here, the roles of HDAC3 in ligand-independent repression, gene repression by orphan NRs, NRs antagonist action, ligand-induced repression, and the activation of a transcriptional coactivator are reviewed. In addition, some perspectives regarding the non-canonical mechanisms of HDAC3 action are discussed.

Dissecting Histone Deacetylase 3 in Multiple Disease Conditions: Selective Inhibition as a Promising Therapeutic Strategy.

The acetylation of histone and non-histone proteins has been implicated in several disease states. Modulation of such epigenetic modifications has therefore made histone deacetylases (HDACs) important drug targets. HDAC3, among various class I HDACs, has been signified as a potentially validated target in multiple diseases, namely, cancer, neurodegenerative diseases, diabetes, obesity, cardiovascular disorders, autoimmune diseases, inflammatory diseases, parasitic infections, and HIV. However, only a handful of HDAC3-selective inhibitors have been reported in spite of continuous efforts in design and development of HDAC3-selective inhibitors. In this Perspective, the roles of HDAC3 in various diseases as well as numerous potent and HDAC3-selective inhibitors have been discussed in detail. It will surely open up a new vista in the discovery of newer, more effective, and more selective HDAC3 inhibitors.

Fluoxetine regulates eEF2 activity (phosphorylation) via HDAC1 inhibitory mechanism in an LPS-induced mouse model of depression

BackgroundSelective serotonin reuptaker inhibitors, including fluoxetine, are widely studied and prescribed antidepressants, while their exact molecular and cellular mechanism are yet to be defined. We investigated the involvement of HDAC1 and eEF2 in the antidepressant mechanisms of fluoxetine using a lipopolysaccharide (LPS)-induced depression-like behavior model.MethodsFor in vivo analysis, mice were treated with LPS (2 mg/kg BW), fluoxetine (20 mg/kg BW), HDAC1 activator (Exifone: 54 mg/kg BW) and NH125 (1 mg/kg BW). Depressive-like behaviors were confirmed via behavior tests including OFT, FST, SPT, and TST. Cytokines were measured by ELISA while Iba-1 and GFAP expression were determined by immunofluorescence. Further, the desired gene expression was measured by immunoblotting. For in vitro analysis, BV2 cell lines were cultured; treated with LPS, exifone, and fluoxetine; collected; and analyzed.ResultsMice treated with LPS displayed depression-like behaviors, pronounced neuroinflammation, increased HDAC1 expression, and reduced eEF2 activity, as accompanied by altered synaptogenic factors including BDNF, SNAP25, and PSD95. Fluoxetine treatment exhibited antidepressant effects and ameliorated the molecular changes induced by LPS. Exifone, a selective HDAC1 activator, reversed the antidepressant and anti-inflammatory effects of fluoxetine both in vivo and in vitro, supporting a causing role of HDAC1 in neuroinflammation allied depression. Further molecular mechanisms underlying HDAC1 were explored with NH125, an eEF2K inhibitor, whose treatment reduced immobility time, altered pro-inflammatory cytokines, and NLRP3 expression. Moreover, NH125 treatment enhanced eEF2 and GSK3β activities, BDNF, SNAP25, and PSD95 expression, but had no effects on HDAC1.ConclusionsOur results showed that the antidepressant effects of fluoxetine may involve HDAC1-eEF2 related neuroinflammation and synaptogenesis.

The Role of HDACs and HDACi in Cartilage and Osteoarthritis.

Epigenetics plays an important role in the pathogenesis and treatment of osteoarthritis (OA). In recent decades, HDAC family members have been associated with OA. This paper aims to describe the different role of HDACs in the pathogenesis of OA through interaction with microRNAs and the regulation of relevant signaling pathways. We found that HDACs are involved in cartilage and chondrocyte development but also play a crucial role in OA. However, the distinct HDAC mechanism in the pathogenesis and treatment of OA require further investigation. Furthermore, HDAC inhibitors (HDACi) can protect cartilage from disease, which may represent a potential therapeutic approach against OA.

Histone Deacetylases Inhibitors in Neurodegenerative Diseases, Neuroprotection and Neuronal Differentiation.

Histone deacetylases (HADC) are the enzymes that remove acetyl group from lysine residue of histones and non-histone proteins and regulate the process of transcription by binding to transcription factors and regulating fundamental cellular process such as cellular proliferation, differentiation and development. In neurodegenerative diseases, the histone acetylation homeostasis is greatly impaired, shifting towards a state of hypoacetylation. The histone hyperacetylation produced by direct inhibition of HDACs leads to neuroprotective actions. This review attempts to elaborate on role of small molecule inhibitors of HDACs on neuronal differentiation and throws light on the potential of HDAC inhibitors as therapeutic agents for treatment of neurodegenerative diseases. The role of HDACs in neuronal cellular and disease models and their modulation with HDAC inhibitors are also discussed. Significance of these HDAC inhibitors has been reviewed on the process of neuronal differentiation, neurite outgrowth and neuroprotection regarding their potential therapeutic application for treatment of neurodegenerative diseases.

Investigating Oncogenic Roles of Long Intergenic Non‐Protein Coding RNA 461 (LINC00461) in HDAC6‐Mediated Glioblastoma Malignancy

Glioblastoma (GBM) is the most complex, difficult‐to‐treat, aggressive, and lethal type of brain tumor. Thus, studies are urgently needed to determine the molecular mechanisms of GBM malignancy and develop novel concepts for treating the disease. According to our previous study, the selective histone deacetylase 1, 2, 6 (HDAC1, 2, 6) inhibitor MPT0B291 prevents the development of temozolomide (TMZ) resistance in GBM cells and prolongs the survival of mice bearing orthotopic GBM xenografts. Although HDACs are known to regulate the balance of lysine acetylation on histones and nonhistone substrates, the role of HDACs in regulating long non‐coding RNAs (lncRNAs) affecting GBM malignancy remains unclear. By performing microarray analysis, we identified an evolutionary conserved lncRNA LINC00461 that was clearly reduced by MPT0B291 in both TMZ‐resistant GBM cells and stem‐like tumorspheres. Additionally, we found that LINC00461 depletion suppressed GBM cell proliferation via G1 phase arrest. Because the miRNA‐411‐5p/topoisomerase II alpha (TOP2A) axis is known as a target of LINC00461 for controlling chromosome segregation during mitosis, we examined the TOP2A levels and verified that both MPT0B291 treatment and LINC00461 silencing caused dramatic decreases in TOP2A expression. Furthermore, we identified the interaction between HDAC6 and subunit 6 of CCR4‐NOT exoribonuclease complex (CNOT6), an acetylation‐activated deadenylase that promotes RNA degradation. In conclusion, this study will increase the understanding of the role of LINC00461 in GBM malignant properties and reveal whether targeting the HDACs/CCR4‐NOT/LINC00461 axis and its downstream effectors with a selective inhibitor is an effective therapeutic strategy against GBMs.Support or Funding InformationThis work was supported by grants from the Ministry of Science and Technology (MOST 106‐6601‐003‐112_15060508367900001 &amp; 107‐6601‐004‐112_15553117427110001).

Role of HDAC2 in Regulating Protein Thiol Redox State, Monocyte Function and Atherosclerosis

Role of HDAC2 in Regulating Protein Thiol Redox State, Monocyte Function and Atherosclerosis

Histone deacetylase 1 induced by neddylation inhibition contributes to drug resistance in acute myelogenous leukemia

ObjectiveThis study aimed to investigate the function and mechanism of neddylation of HDAC1 underlying drug resistance of AML cells.MethodsEvaluation experiments of effects of HDAC1 on drug resistance of AML cells were performed with AML cell transfected with constructs overexpressing HDAC1 or multi-drug resistance AML cells transfected with siRNA for HDAC1 through observing cell viability, percentage of apoptotic cell, doxorubicin-releasing index and multidrug resistance associated protein 1 (MRP1) expression. Neddylation or ubiquitination of HDAC1 was determined by immunoprecipitation or Ni2+ pull down assay followed by western blot. The role of HDAC1 was in vivo confirmed by xenograft in mice.ResultsHDAC1 was significantly upregulated in refractory AML patients, and in drug-resistant AML cells (HL-60/ADM and K562/A02). Intracellular HDAC1 expression promoted doxorubicin resistance of HL-60, K562, and primary bone marrow cells (BMCs) of remission AML patients as shown by increasing cell viability and doxorubicin-releasing index, inhibiting cell apoptosis. Moreover, HDAC1 protein level in AML cells was regulated by the Nedd8-mediated neddylation and ubiquitination, which further promoted HDAC1 degradation. In vivo, HDAC1 overexpression significantly increased doxorubicin resistance; while HDACs inhibitor Panobinostat markedly improved the inhibitory effect of doxorubicin on tumor growth. Furthermore, HDAC1 silencing by Panobinostat and/or lentivirus mediated RNA interference against HDAC1 effectively reduced doxorubicin resistance, resulting in the inhibition of tumor growth in AML bearing mice.ConclusionOur findings suggested that HDAC1 contributed to the multidrug resistance of AML and its function turnover was regulated, at least in part, by post-translational modifications, including neddylation and ubiquitination.

&lt;p&gt;HOXA10 knockdown inhibits proliferation, induces cell cycle arrest and apoptosis in hepatocellular carcinoma cells through HDAC1&lt;/p&gt;

BackgroundHomeobox A10 (HOXA10) has been implicated in the development and progression of various human cancers. However, the precise biological functions of HOXA10 in hepatocellular carcinoma (HCC) have not been defined.MethodsIn this study, we examined mRNA expression by quantitative real-time PCR (qRT-PCR) of HOXA10 as well as histone deacetylase (HDAC) and protein levels by Western blot of HOXA10, HDAC1, Cyclin D1, proliferating cell nuclear antigen (PCNA), Survivin and p53 acetylation in HCC tissues and cell lines. We also assessed cell proliferation using Cell Counting Kit-8 (CCK-8) and analyzed cell cycle by flow cytometry. Furthermore, tumor growth of HCC cells in vivo was monitored using the nude mouse xenograft model. Finally, HDAC1 promoter activity and binding in HCC cell lines were detected by luciferase reporter assay and chromatin immunoprecipitation (ChIP), respectively.ResultsWe uncovered the elevated expression of HOXA10 in HCC tissues compared to adjacent normal liver tissues. RNA interference-mediated knockdown of HOXA10 inhibited HCC cell proliferation both in vitro and in vivo. HOXA10 knockdown also induced cell cycle arrest at G0/G1 phase and apoptosis, which were accompanied with the reduced expression of Cyclin D1, PCNA and Survivin. Notably, HOXA10 knockdown enhanced p53 acetylation (Lys382), which is crucial to the activation of p53. Likewise, HOXA10 knockdown suppressed the transcription of HDAC1, a potential deacetylase for p53. In line with these observations, HDAC1 downregulation abrogated the effects of HOXA10 overexpression on proliferation, cell cycle progression, apoptosis and p53 acetylation, indicating the role of HDAC1 in mediating HOXA10 functions.ConclusionOur results demonstrate that HOXA10 knockdown inhibits proliferation, induces cell cycle arrest and apoptosis in HCC cells by regulating HDAC1 transcription.

Abstract 4723: Combinatorial efficacy of anti-PD1 treatment and selective histone deacetylase 6 (HDAC6) inhibition in chronic lymphocytic leukemia (CLL)

Abstract A suppressive microenvironment allows CLL B cells to avoid immune surveillance. Coinhibitory antigens, anti-inflammatory cytokines and skewed immune populations support malignancy and contribute to poorer immune responses in CLL patients. Novel approaches to counter immunosuppression are therefore being explored. The HDAC family of proteins epigenetically regulate immune-related pathways in cancer and may be noteworthy immunomodulatory targets. In addition to the recognized role of HDACs in cell survival, HDACi may alter inflammatory status of immune and tumor cells. We have previously reported that HDAC6 regulates IL-10 transcription, and is responsible for T cell anergy in murine and human APCs. IL-10 is secreted by CLL B cells and is thought to influence immunosuppression. Therefore, we hypothesized that HDAC6i could reverse immunosuppression in CLL for antitumor benefit. The purpose of this study was to determine 1) the effects of selective HDAC6i on CLL immune biology and 2) whether combination with HDAC6i could improve efficacy of anti-PD1 for CLL therapy. To accomplish these aims, the euTCL1 and euTCL1/HDAC6KO adoptive transfer models of murine CLL were utilized. ACY738 (selective HDAC6i) was administered orally in chow at 25mpk daily. Anti-PD1 was administered intraperitoneally 3x per week at 3mpk. CLL surface antigens were analyzed via flow cytometry. Functional mixed lymphocyte assays were performed ex vivo, measuring IFNg production, and Th1/Th2 factors were examined via qRT-PCR in CLL T cells. Early PD-L1 expression on B cells correlated to CLL burden in euTCL1 mice. Post ACY738 treatment, euTCL1 B cells downregulated expression of PD-L1 and plasma IL-10. In addition, PD-1 and CTLA4 was decreased on CD4+, CD8+, Tregs and effector memory T cells. Splenic T cells from ACY738 mice upregulated TBET and downregulated GATA3, indicative of a less exhausted phenotype. Subsequently, euTCL1 B cells were treated ex vivo with ACY738 and cocultured with T cells. T cell activation (IFNg production) was increased after coculture with treated B cells compared to control B cells. We then hypothesized that ACY738 could be rationally be combined with anti-PD1 mAb for CLL treatment. Mice treated with anti-PD1 accumulated fewer CD5+ B cells, confirming that PD-1/PD-L1 blockade demonstrated anti-CLL benefit. Strikingly, combination of ACY738 and anti-PD1 further delayed the growth of CLL cells compared to either single agent. Consistently, anti-PD1 treatment in euTCL1/HDAC6KO mice further delayed CLL development. In conclusion, we report here that HDAC6i can reinvigorate CLL T cells, and combination of HDAC6i with anti-PD1 increased anti-CLL efficacy in vivo. This work provides evidence that this combination could be clinically investigated to simultaneously reduce tumor burden and improve immune function in CLL patients. Citation Format: Kamira Maharaj, John Powers, Alex Achille, Eva Sahakian, Javier Pinilla-Ibarz. Combinatorial efficacy of anti-PD1 treatment and selective histone deacetylase 6 (HDAC6) inhibition in chronic lymphocytic leukemia (CLL) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4723.

Role of HDAC1 in the progression of gastric cancer and the correlation with lncRNAs

Gastric cancer (GC) is a common life-threatening cancer type worldwide, with an increasing prevalence and a high rate of mortality. Due to limitations in clinical treatment, surgery has become the most efficient strategy for the treatment of GC. It is urgent to identify novel biomarkers, which are useful for the diagnosis of GC and for improving the survival rate of patients with GC. HDACs are multi-functional proteins and are involved in regulating gene expression, cell proliferation and the epigenetic regulation. However, the precise role of HDACs in the progression of GC remains unknown. The present study demonstrated that HDAC1 is involved in the promotion of GC cell proliferation, possibly by upregulating the expression of the lncRNAs, BC01600 and AF116637, in the tissues of patients with GC. Abnormal expression profiles of lncRNAs were observed in the tissues of patients with GC. lncRNAs were analyzed in the GSE64951 and GSE19826 databases, and it was revealed that BC01600 and AF116637 were two typically upregulated lncRNAs. Furthermore, it was revealed that BC01600 and AF116637 are regulated by HDAC1, as evidenced by decreased expression of these two lncRNAs in HDAC1-knockout SC-M1 cell lines, and by reduced expression of HDAC1 in these two lncRNA-knockout SC-M1 cell lines. Silencing of HDAC1 decreased the proliferation and increased the apoptosis of SC-M1 cell lines, but had no effect on the migration of the SC-M1 cell lines. The present study provided evidence of the importance of HDAC1 in the progression of SC-M1, and the association between HDAC1 and the expression of lncRNAs. The results of the present study indicated that HDAC1 may be a promising target for the clinical treatment of GC.

Histone Deacetylase 2 Regulates Autophagy &lt;i&gt;via&lt;/i&gt; ULK1-NLRP3-Pyroptosis Pathway Associated with the Inflammatory Response in Acute Liver Failure

Background: Pyroptosis is new necrosis pattern of hepatocytes during liver inflammation in acute liver failure (ALF). The autophagy-NLRP3-pyroptosis pathway plays an important role in the process of cell damage. HDAC2 is a regulator of the autophagy protein ULK1. Methods: The role of HDAC2 on ULK1-NLRP3-pyroptosis pathway during ALF was decteced in clinlincal sample. It was investigated the mechanism in transfected cells and ALF mouse model. The RNA-seq technology revealed that ULK1 was a negative regulatory molecule by HDAC2. Findings: The results from clinical specimens showed that with the elevated liver severity, the levels of HDAC2, NLRP3, caspase 1, GSDMD, IL-18 and IL-1β in liver tissue increased gradually, the expression of ULK1 decreased. Targeting knockdown or overexpression of HDAC2 could accordingly up-regulate or down-regulate ULK1. Then NLRP3-pyroptosis pathway was inhibited and activated. The results of mass spectrometry showed that ULK1 K68 lysine site was modified by acetylation. The degree of acetylation of K68 site in ALF liver tissue was lower than normal liver tissue. Furthermore, the study using ULK1 acetyl-silencing mutants (K68R) showed that HDAC2 could hardly attenuat D-galactosamine (D-Gal) and TNF-α induced pyroptosis in K68R-transfected L02 cells. The ALF mouse was significantly attenuated by HDAC2 innibitor in mice model, leading to reduced liver tiusse pyroptosis and liver function. Duing the process of injury, HDAC2 and pyroptosis exserted the antagonistic effect with ULK1. Interpretation: HDAC2 in hepatocytes plays a pivotal role in an ULK1-NLRP3 pathway driven auto-amplification of pyroptosis in the inflammation and liver damage of ALF. One of the important mechanisms is that inhibition HDAC2 to reduce pyroptosis may be by modulating the K68 lysine site of ULK1. These results provide a treatment strategy against hepatocyte injury in ALF. Funding Statement: This work was supported by the Natural Science Foundation of China (81870413). Declaration of Interests: The authors declare that they have no conflicts of interests. Ethics Approval Statement: Animal experiments were approved by the Animal Ethics Committee of Renmin Hospital of Wuhan University. The ethical approval for research involving animal number was WDRM (Welfare) 20181018. The ALF patient and normal donor liver tissues were provided by the Liver Transplantation Center of Renmin Hospital of Wuhan University. The study was signed with informed consent of patient and agreed with Ethics Committee of Renmin Hospital of Wuhan University.