Use Of Histone Deacetylase Inhibitors Research Articles

Chemical Screen Identifies Diverse and Novel Histone Deacetylase Inhibitors as Repressors of NUT Function: Implications for NUT Carcinoma Pathogenesis and Treatment.

NUT carcinoma (NC), characterized most commonly by the BRD4-NUTM1 fusion, is a rare, aggressive variant of squamous carcinoma with no effective treatment. BRD4-NUT drives growth and maintains the poorly differentiated state of NC by activating pro-growth genes such as MYC, through the formation of massive, hyperacetylated, superenhancer-like domains termed megadomains. BRD4-NUT-mediated hyperacetylation of chromatin is facilitated by the chromatin-targeting tandem bromodomains of BRD4, combined with NUT, which recruits the histone acetyltransferase, p300. Here, we developed a high-throughput small-molecule screen to identify inhibitors of transcriptional activation by NUT. In this dCAS9-based GFP-reporter assay, the strongest hits were diverse histone deacetylase (HDAC) inhibitors. Two structurally unrelated HDAC inhibitors, panobinostat and the novel compound, IRBM6, both repressed growth and induced differentiation of NC cells in proportion to their inhibition of NUT transcriptional activity. These two compounds repressed transcription of megadomain-associated oncogenic genes, such as MYC and SOX2, while upregulating pro-differentiation, non-megadomain-associated genes, including JUN, FOS, and key cell-cycle regulators, such as CDKN1A. The transcriptional changes correlate with depletion of BRD4-NUT from megadomains, and redistribution of the p300/CBP-associated chromatin acetylation mark, H3K27ac, away from megadomains toward regular enhancer regions previously populated by H3K27ac. In NC xenograft models, we demonstrated that suppression of tumor growth by panobinostat was comparable with that of bromodomain inhibition, and when combined they improved both survival and growth suppression. IMPLICATIONS: The findings provide mechanistic and preclinical rationale for the use of HDAC inhibitors, alone or combined with other agents, in the treatment of NUT carcinoma.

Histone Deacetylase Inhibitors Abolish HBZ Protein Expression and Induce Cell Death in HTLV-1 Related Adult T-Cell Leukemia-Lymphoma

Background:Adult T-cell leukemia-lymphoma (ATL) is a malignancy with dismal prognosis caused by HTLV-1. ATL is incurable by conventional drugs. Histone deacetylase (HDAC) inhibitors (HDIs) are broadly active anti-neoplastic agents that can be cautiously exploited in the treatment of viral related lymphomas. HTLV-1 usually establishes lifelong latency in human CD4+ T-cells, which in turn propagate and persist as result of the multifaceted functions of HTLV-1 basic zipper factor (HBZ) through various signaling pathways that promote growth and proliferation, and block apoptosis and cell senescence. All ATL cells harbor at least one copy of latent intact HTLV-1 provirus in most cases, and unlike Tax, all tumors express HBZ from the negative 3‘ proviral strand via SP-1 activity. The HTLV-1 promoter is negatively regulated by HDACs at the 5‘ long terminal repeat (LTR), and by HBZ, which disrupts Tax positive interaction with the transcriptional activator p300/CBP, thus blocking viral transcription. Therefore, treatment of HTLV-1 infected cells with HDIs can induce expression of Tax protein, which is highly immunogenic, and which could promote immune-mediated clearance of ATL cells in vivo.Methods:Low-passage IL-2 dependent ATL cell lines established from patients with acute type ATL and freshly isolated ATL cells were treated with several HDIs (VPA, sodium butyrate, vorinostat, belinostat, panabinostat, and mocetinostat) at various doses and time points. Apoptosis was measured by annexin V and FACS analysis. Expression of HBZ protein, Tax, acetyl and total histone 3 subunits (H3), BIM, caspase 3, caspase 9, Jun B, c-Jun, Jun D, and Sp-1 were measured by Western blots before and after HDI treatment. HBZ and Tax mRNA expression was measured by quantitative RT-PCR. SP-1 binding to HTLV-1 specific oligonucleotide consensus sequence was measured by gel shift assay using nuclear protein extracts before and after HDI treatment.Results:HDIs sequentially increased acetylated H3 levels, blocked HBZ protein, upregulated Tax expression, stabilized BIM, and induced cleavage of pro-caspases 9 and 3 (intrinsic apoptotic pathway), resulting in apoptosis of ATL cells. HDIs tested (VPA and belinostat) blocked expression of Jun-B, which is known to be upregulated by HBZ, while no significant effects were observed on c-Jun and Jun D protein levels. HDIs tested (VPA, belinostat, and panabinostat) did not significantly alter spliced-HBZ RNA levels or affect SP-1 binding to HBZ promoter-specific oligonucleotide sequence, suggesting a post-translational mechanism may contribute to abrogation of HBZ in ATL cells.Conclusions:Our data demonstrate that HDIs target ATL cells in part by abrogating HBZ protein, which could negatively impact the longevity of ATL and HTLV-1 cells in vivo. Long-term clinical use of HDIs might be beneficial for eliminating residual ATL cells after definitive treatment. A pilot clinical trial testing belinostat-based consolidation therapy for aggressive leukemic ATL types is currently ongoing at our institution (available at Clinicaltrials.gov , NCT02737046). DisclosuresNo relevant conflicts of interest to declare.

A Phase II Trial Evaluating the Use of the Histone Deacetylase Inhibitor Panobinostat for Graft-Versus-Host Disease (GVHD) Prevention

Introduction: The use of histone deacetylase inhibitors has shown promising results in the prevention of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic cell transplant (HCT) (Choi et al, Lancet Oncology, 2014). In this protocol, we will build on prior experience by adding panobinostat to tacrolimus and sirolimus for GVHD prevention (Pidala et al, Haematologica, 2012 and idem, 2015). Panobinostat has been proven to be tolerable in our prior study of GVHD treatment in addition to glucocorticoids (Perez et al, ASH 2014 Abstract), in myelodysplastic syndrome (MDS) maintenance (Bug et al, ASH 2015 Abstract), and in early post-HCT epigenetic therapy (panobinostat and decitibine) followed by donor lymphocyte infusion (Cornelissen et al, ASH 2016 Abstract). We hypothesize that panobinostat added to tacrolimus-sirolimus may abolish GVHD while sparing the graft-versus-leukemia effect by enhancing T regulatory cell development and modulating antigen presentation.Methods: This is a phase II Simon's minimax two-stage design; the null hypothesis will be rejected if the number of patients with grade II-IV aGVHD is 12 or less among 38 evaluable patients (≤31.6% incidence rate at day 100). To date, we have enrolled 27 patients with hematological malignancies (3 with AML, 3 with ALL, 3 with MPN, 6 with MDS, and 1 each with CML, chronic neutropenia, PTCL, and BPCDN) and a median age of 56 years (range, 29-72 years). These patients have been followed for at least 100 days after an HLA-compatible unrelated-donor (n=19) or related-donor (n=6) HCT. The conditioning regimen was BU/FLU AUC 5300 for 4 days (16 patients), BU/FLU AUC 3500 for 4 days (1 patient), or fludarabine/melphalan 140 mg/m2 (10 patients). All participants received G-mobilized peripheral blood stem cells. Panobinostat at 5 mg orally 3 times/week was initiated on day -5 or -6 and continued for 26 weeks; panobinostat stopping criteria included GVHD requiring corticosteroids (1 mg/kg) or toxicity. Tacrolimus was given starting on day -3, with taper recommended from day +50, and sirolimus was started on day -1 with taper recommended from day +365.Results: Engraftment occurred at a median of 14.5 days (range, 12-18 days) for ANC over 500/µL and median of 15.5 days (range, 10-27 days) for platelets over 20,000/µL. Sinusoidal obstruction syndrome was seen in 1 patient (resolved). Among 27 patients, 7 completed panobinostat treatment as planned at day 100. The other 20 patients stopped panobinostat due to GVHD treated with 1 mg/kg corticosteroids (n=4), myelosuppression possible related to panobinostat (n=8), mucositis (n=2), QTCF prolongation (n=1), comorbidities (n=5), patient refusal (n=1), peripheral edema/renal failure possible related to panobinostat (n=1), rash/angioedema (n=1) definitively related to panobinostat), and facial erythema possible related to panobinostat (n=1). Among 27 evaluable patients, aGVHD was seen in 6 of 27 patients (22%), with 5 patients having grade II (4 responded to corticosteroids; 1 resolved with no corticosteroids) and 1 having grade III GVHD (Jakafi stopped pre-HCT resolved with re-initiation). We did not observe an increase in infection risk. None of the 27 patients died within 100 days, and 7 relapsed at 3-8 months (3 with AML FLT3+, 1 with AML DNMT3A and IDH1 mutations, 1 with ALL, 1 with MPN and 1 with MDS-complex cytogenetics).Conclusions: The combination of tacrolimus-sirolimus-panobinostat seems to be an effective strategy to reduce aGVHD in myeloablated unrelated-donor or related-donor transplant with a 22% incidence of aGVHD compared with 43% reported with tacrolimus-sirolimus in our previous study. Follow-up and accrual completion are required, and correlative studies are planned that will compare results with control patients receiving tacrolimus-sirolimus only. DisclosuresKharfan-Dabaja:Alexion Pharmaceuticals: Speakers Bureau; Incyte: Speakers Bureau; Seattle Genetics: Speakers Bureau.

KDELR2 promotes breast cancer proliferation via HDAC3‐mediated cell cycle progression

BackgroundHistone deacetylases (HDACs) engage in the regulation of various cellular processes by controlling global gene expression. The dysregulation of HDACs leads to carcinogenesis, making HDACs ideal targets for cancer therapy. However, the use of HDAC inhibitors (HDACi) as single agents has been shown to have limited success in treating solid tumors in clinical studies. This study aimed to identify a novel downstream effector of HDACs to provide a potential target for combination therapy.MethodsTranscriptome sequencing and bioinformatics analysis were performed to screen for genes responsive to HDACi in breast cancer cells. The effects of HDACi on cell viability were detected using the MTT assay. The mRNA and protein levels of genes were determined by quantitative reverse transcription‐PCR (qRT‐PCR) and Western blotting. Cell cycle distribution and apoptosis were analyzed by flow cytometry. The binding of CREB1 (cAMP‐response element binding protein 1) to the promoter of the KDELR (The KDEL (Lys‐Asp‐Glu‐Leu) receptor) gene was validated by the ChIP (chromatin immunoprecipitation assay). The association between KDELR2 and protein of centriole 5 (POC5) was detected by immunoprecipitation. A breast cancer‐bearing mouse model was employed to analyze the effect of the HDAC3‐KDELR2 axis on tumor growth.ResultsKDELR2 was identified as a novel target of HDAC3, and its aberrant expression indicated the poor prognosis of breast cancer patients. We found a strong correlation between the protein expression patterns of HADC3 and KDELR2 in tumor tissues from breast cancer patients. The results of the ChIP assay and qRT‐PCR analysis validated that HDAC3 transactivated KDELR2 via CREB1. The HDAC3‐KDELR2 axis accelerated the cell cycle progression of cancer cells by protecting the centrosomal protein POC5 from proteasomal degradation. Moreover, the HDAC3‐KDELR2 axis promoted breast cancer cell proliferation and tumorigenesis in vitro and in vivo.ConclusionOur results uncovered a previously unappreciated function of KDELR2 in tumorigenesis, linking a critical Golgi‐the endoplasmic reticulum traffic transport protein to HDAC‐controlled cell cycle progression on the path of cancer development and thus revealing a potential therapeutical target for breast cancer.

A systematic review on the management of pruritus in patients with cutaneous T-cell lymphoma

Introduction: Cutaneous T-cell lymphomas (CTCLs) represent a rare group of primary cutaneous lymphomas. Pruritus is common in patients with CTCL and is severe and intractable in the subtypes Sézary syndrome (SS) and folliculotropic mycosis fungoides (MF). Materials and methods: We conducted a systematic review on interventions demonstrating efficacy in reducing pruritus in patients with CTCL. The primary aim of our study was to identify disease-directed and itch-directed therapies effective in reducing CTCL-associated pruritus. Our secondary aim was to outline various tools used to quantify itch in clinical studies. Results: Our study identified multiple disease-directed therapies effective in reducing CTCL-associated pruritus. Most evidence supported the use of histone deacetylase inhibitors. For the agents romidepsin, vorinostat, and quisinostat, reduction in pruritus was achieved in both disease responders and nonresponders. Various therapies were effective in managing pruritus associated with SS and folliculotropic MF. Vorinostat is effective in reducing pruritus in patients with SS. Extracorporeal photophoresis, total skin electron beam therapy, and romidepsin are effective in reducing pruritus in patients with folliculotropic MF. The antiemetic aprepitant is an effective targeted treatment of CTCL-associated pruritus. Aprepitant demonstrated efficacy in reducing pruritus in patients with all stages of MF, including patients with SS. Lignocaine administered via continuous subcutaneous infusion is effective in reducing pruritus in patients with advanced-stage MF, including patients with SS. The most frequently used tools to quantify itch were the Visual Analogue Scale and Numerical Rating Scale. Definitions of a significant reduction in pruritus were extremely varied between studies. Discussion: To our knowledge, this is the first systematic review specifically addressing the management of itch in patients with CTCL. Patients with all stages of CTCL were represented across included studies, including patients with folliculotropic MF and SS. A wide range of treatment options were identified, including options appropriate for patients with end-stage disease.

Histone Deacetylase Inhibitors in the Treatment of Hepatocellular Carcinoma: Current Evidence and Future Opportunities.

Hepatocellular carcinoma (HCC) remains a major health problem worldwide with a continuous increasing prevalence. Despite the introduction of targeted therapies like the multi-kinase inhibitor sorafenib, treatment outcomes are not encouraging. The prognosis of advanced HCC is still dismal, underlying the need for novel effective treatments. Apart from the various risk factors that predispose to the development of HCC, epigenetic factors also play a functional role in tumor genesis. Histone deacetylases (HDACs) are enzymes that remove acetyl groups from histone lysine residues of proteins, such as the core nucleosome histones, in this way not permitting DNA to loosen from the histone octamer and consequently preventing its transcription. Considering that HDAC activity is reported to be up-regulated in HCC, treatment strategies with HDAC inhibitors (HDACIs) showed some promising results. This review focuses on the use of HDACIs as novel anticancer agents and explains the mechanisms of their therapeutic effects in HCC.

Targeting Histone Modifications in Bone and Lung Metastatic Cancers.

Breast cancer frequently metastasizes to the bone and lung, but the ability to treat metastatic tumor cells remains a pressing clinical challenge. Histone deacetylases (HDACs) and histone acetyltransferases (HATs) have emerged as promising targets since these enzymes are aberrantly expressed in numerous cancers and regulate the expression of genes that drive tumorigenesis and metastasis. This review focuses on the abnormal expression of histone-modifying enzymes in cancers that have a high tropism for the bone and lung and explores the clinical use of histone deacetylase inhibitors for the treatment and prevention of metastasis to these sites. Preclinical studies have demonstrated that the role for HDACs is highly dependent on tumor type and stage of disease progression. HDAC inhibitors can induce apoptosis, senescence, cell differentiation, and tumor dormancy genes and inhibit angiogenesis, making these promising therapeutics for the treatment of metastatic disease. HDAC inhibitors are already FDA approved for hematologic malignancies and are in clinical trials with standard-of-care chemotherapies and targeted agents for several solid tumors, including cases of metastatic disease. However, these drugs can negatively impact bone homeostasis. Although HDAC inhibitors are not currently administered for the treatment of bone and lung metastatic disease, preclinical studies have shown that these drugs can reduce distant metastasis by targeting molecular factors and signaling pathways that drive tumor cell dissemination to these sites. Thus, HDAC inhibitors in combination with bone protective therapies may be beneficial in the treatment of bone metastatic cancers.

Histone Deacetylase Inhibitors Romidepsin and Vorinostat Promote Hepatitis B Virus Replication by Inducing Cell Cycle Arrest.

Background and AimsChronic hepatitis B virus (HBV) infection is a global public health challenge. HBV reactivation usually occurs in cancer patients after receiving cytotoxic chemotherapy or immunosuppressive therapies. Romidepsin (FK228) and vorinostat (SAHA) are histone deacetylase inhibitors (HDACi) approved by the Food and Drug Administration as novel antitumor agents. The aim of this study was to explore the effects and mechanisms of HDACi treatment on HBV replication.MethodsTo assess these effects, human hepatoma cell lines were cultured and cell viability after FK228 or SAHA treatment was measured by the CCK-8 cell counting kit-8 assay. Then, HBV DNA and RNA were quantified by real-time PCR and Southern blotting. Furthermore, analysis by western blotting, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, and flow cytometry was performed.ResultsFK228/SAHA treatment significantly promoted HBV replication and biosynthesis in both HBV-replicating cells and HBV-transgenic mouse model. Flow cytometry assay indicated that FK228/SAHA enhanced HBV replication by inducing cell cycle arrest through modulating the expression of cell cycle regulatory proteins. In addition, simultaneous inhibition of HDAC1/2 by FK228 promoted HBV replication more effectively than the broad spectrum HDAC inhibitor SAHA.ConclusionsOverall, our results demonstrate that cell cycle blockage plays an important role in FK228/SAHA-enhanced HBV replication, thus providing a potential avenue for rational use of HDACi in patients with chronic hepatitis B.

Inhibition of histone deacetylase promotes a neuroprotective mechanism in an experimental model of Parkinson's disease.

Therapies targeting histone deacetylase (HDAC) have gained wider attention in the treatment of various clinical conditions. However, the use of HDAC inhibitors in pre-clinical trials in the case of Parkinson's disease (PD) is very limited. In the present study, the HDAC inhibitor, entinostat, was tested in animals induced with Parkinson's disease experimentally. Wistar male rats (150 ±10 g) were administered with rotenone (2 mg/kg/day, s.c.) for 21 days to induce PD, while entinostat (20 mg/kg) was given intraperitoneally. Then, the neurological functions, PD markers, and HDACs were analysed in the control and experimental animals. The results demonstrated that rats that received entinostat displayed progressive motor, behavioural, and neurological function with attenuated α-synuclein and improved tyrosine-hydroxylase compared to control cells. Moreover, the induction of PD in rats demonstrated reduced levels of H2S, dopamine, 3, and 4-dihydroxyphenylacetic acid (DOPAC), and increased monoamine oxidase activity in PD rats. However, the rats that received entinostat demonstrated progressive levels of dopa and DOPAC, with attenuated levels of HDAC-2, -4, and -6 mRNA in the PD rats compared to controls. On the other hand, elevated (p < 0.01) levels of PD marker genes such as GDF3 and NMDA2b were reduced, with a significant increase in neuroprotective genes such as VDAC3 and CBX5 in entinostat-supplemented rats. The study results suggest that inhibition of HDAC systematically improves the neurological functions, and hence treatments, emphasizing that HDACI, as the speculated mechanism, will be a promising mode of treatment in PD.

Lung fibrosis in COVID-19 survivors: histone deacetylase inhibitors as a promising therapeutic strategy

Over the past twenty years, the world has witnessed several viral epidemics such as the Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), influenza A subtype H1N1 virus, Middle East Respiratory Syndrome Coronavirus (MERS-CoV), and more recently the novel SARS-CoV coronavirus 2, which caused the disease COVID-19. The latest epidemic proved to be the most destructive and claimed more than 2 million lives. Today's efforts to combat COVID-19 are focused on controlling the spread of the coronavirus and identifying effective treatment options. Meanwhile, an analysis of data regarding the long-term clinical consequences of previous coronavirus infections (SARS-CoV and MERS-CoV) shows that with the removal of the virus from the body, the pathological process in many cases does not end and can develop into long-term lung damage, in particular, fibrous interstitial disease or pulmonary fibrosis. Thus, pulmonary fibrosis can become an ongoing problem in patients recovering from COVID-19. Therefore, it is necessary now to determine the strategy of preventive measures both to counteract the development of pulmonary fibrosis in patients with COVID-19 during inpatient treatment, and to prevent its occurrence and progression in the long term. Although anti-fibrotic drugs such as pirfenidone and nintedanib have been shown to be effective in reducing the rate of deterioration in lung function, their results have not significantly improved patient recovery. In addition, the use of these drugs has been associated with serious side effects. In this regard, the purpose of this article is to consider the use of histone deacetylase inhibitors (HDACs) as an alternative epigenetic therapy strategy to prevent the development or progression of pulmonary fibrosis in recovered SARS-CoV-2 patients. (English) [ABSTRACT FROM AUTHOR] За последние двадцать лет мир стал свидетелем нескольких вирусных эпидемий, таких как эпидемии коронавируса тяжелого острого респираторного синдрома (SARS-CoV), вируса гриппа A подтипа H1N1, коронавируса ближневосточного респираторного синдрома (MERS-CoV), а недавно и нового коронавируса SARS-CoV-2, вызвавшего заболевание COVID-19. Последняя эпидемия оказалась наиболее разрушительной и унесла с собой более 2 млн человеческих жизней. Сегодняшние усилия в борьбе с COVID-19 направлены, в основном, на контроль распространения коронавируса и определение эффективных вариантов лече- ния. Между тем анализ данных, касающихся долговременных клинических последствий предыдущих коронавирусных инфекций (SARS-CoV и MERS-CoV), показывает, что с выведением вируса из организма патологический процесс во многих случаях не за- вершается и может перерасти в длительное поражение легких, в частности, фиброзное интерстициальное заболевание, или фиброз легких. Таким образом, фиброз легких может стать постоянной проблемой у пациентов, выздоровевших от COVID-19. Поэтому необходимо уже сейчас определить стратегию превентивных мер как по противодействию развития фиброза легких у пациентов с COVID-19 в период стационарного лечения, так и по недопущению его возникновения и прогрессирования в отда- ленной перспективе. Такие антифибротические препараты, как пирфенидон и нинтеданиб показали свою эффективность в сни- жении скорости ухудшения функции легких, тем не менее результаты их применения не дали существенного улучшения в выздоровлении пациентов. Кроме того, прием этих препаратов был связан с развитием серьезных побочных эффектов. В этой свя- зи, цель работы - рассмотреть возможность использования ингибиторов гистондеацетилазы (HDAC, histonedeacetylase) в каче- стве альтернативной эпигенетической стратегии терапии для предотвращения развития или прогрессирования легочного фиб- роза у выздоровевших пациентов с SARS-CoV-2. (Russian) [ABSTRACT FROM AUTHOR] Copyright of Problems of Biological, Medical & Pharmaceutical Chemistry is the property of Russian Physician Public House Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Creation of monoclonal antibody expressing CHO cell lines grown with sodium butyrate and characterization of resulting antibody glycosylation.

Chinese hamster ovary (CHO) cells are the primary mammalian cell lines utilized to produce monoclonal antibodies (mAbs). The upsurge in biosimilar development and the proven health benefits of mAb treatments reinforces the need for innovative methods to generate robust CHO clones and enhance production, while maintaining desired product quality attributes. Among various product titer-enhancing approaches, the use of histone deacetylase inhibitors (HDACis) such as sodium butyrate (NaBu) has yielded promising results. The titer-enhancing effect of HDACi treatment has generally been observed in lower producer cell lines but those studies are typically done on individual clones. Here, we describe a cell line development (CLD) platform approach for creating clones with varying productivities. We then describe a method for selecting an optimal NaBu concentration to evaluate potential titer-enhancing capabilities in a fed-batch study. Finally, a method for purifying the mAb using protein A chromatography, followed by glycosylation analysis using mass spectrometry, is described. The proposed workflow can be applied for a robust CLD process optimization to generate robust clones, enhance product expression, and improve product quality attributes.

Anticancer Effects of Valproic Acid via Regulation of Epigenetic Mechanisms in Non-small-cell Lung Cancer A549 Cell Line.

Epigenetic mechanisms are the most important factors contributing to both the development and metastasis of cancer cells. We aimed to scrutinize the role of epigenetic alternations of genes involved in cancer metastasis, including CD44v6 (metastasis indicator) and Nm23-H1 (a novel tumor suppressor), in the A549 lung cancer cell line. The A549 cells were cultured in the DMEM medium. Valproic acid (VPA) was used as a histone deacetylase inhibitor. Caspase-3 activity was assessed by adding DEVD-pNA substrate to the cell lysate. Gene expression was determined by real-time PCR. Finally, protein expression was assessed by western blot. The results showed that VA significantly decreased the expression of the CD44v6 gene and its protein level. This was further accompanied by lower expressions of MMP-2 and MMP-9 genes. On the other hand, the expression of Nm23-H1 and its protein were significantly increased in the cells accompanied by higher activity of caspase-3 (P ˂ 0.05). Our results showed that epigenetic regulation of CD44v6, Nm23-H1, MMP-2, and MMP-9 might be involved in the pathogenesis and metastasis of lung cancer. Therefore, the use of histone deacetylase inhibitors can be effective in the suppression of metastases and the treatment of these tumors.

The histone deacetylase inhibitor PCI-24781 impairs calcium influx and inhibits proliferation and metastasis in breast cancer.

Histone deacetylases (HDACs) are involved in key cellular processes and have been implicated in cancer. As such, compounds that target HDACs or drugs that target epigenetic markers may be potential candidates for cancer therapy. This study was therefore aimed to identify a potential epidrug with low toxicity and high efficiency as anti-tumor agents.Methods: We first screened an epigenetic small molecule inhibitor library to screen for an epidrug for breast cancer. The candidate was identified as PCI-24781 and was characterized for half maximal inhibitory concentration (IC50), for specificity to breast cancer cells, and for effects on carcinogenesis and metastatic properties of breast cancer cell lines in vitro. A series of in silico and in vitro analyses were further performed of PCI-24781 to identify and understand its target.Results: Screening of an epigenetic inhibitor library in MDA-MB-231 cells, a malignant cancer cell line, showed that PCI-24781 is a potential anti-tumor drug specific to breast cancer. Ca2+ related pathways were identified as a potential target of PCI-24781. Further analyses showed that PCI-24781 inhibited Gαq-PLCβ3-mediated calcium signaling by activating the expression of regulator of G-protein signaling 2 (RGS2) to reduce cell proliferation, metastasis, and differentiation, resulting in cell death in breast cancer. In addition, RGS2 depletion reversed anti-tumor effect and inhibition of calcium influx induced by PCI-24781 treatment in breast cancer cells.Conclusions: We have demonstrated that PCI-24781 is an effective anti-tumor therapeutic agent that targets calcium signaling by activating RGS2. This study also provides a novel perspective into the use of HDAC inhibitors for cancer therapy.

Current Therapies in Nephrotic Syndrome: HDAC inhibitors, an Emerging Therapy for Kidney Diseases

• Nephrotic syndrome (NS) is one among the chronic kidney conditions occurring in children as well as in adult population. • Conventional therapies for NS include treatment with steroids, ACE inhibitors and monoclonal antibodies, with no universal treatment for the condition as yet. • HDAC inhibitors have been greatly explored in the recent past for their anti-fibrotic, anti-inflammatory and immunosuppressive effects in several tissues and organs. • Increasing evidence suggests that treatment with HDAC inhibitors can attenuate renal sclerosis, fibrosis and proteinuria associated with chronic kidney diseases. • HDAC inhibitors can be considered as an emerging therapy for treating NS however; further preclinical and clinical investigations are indispensable. Nephrotic syndrome (NS) is one amongst the foremost chronic kidney conditions occurring in children as well as in adults with a characteristic feature of podocyte injury. Currently, there is no refined treatment available for this condition and in most of the cases, the treatment is essentially experiential. Therapies for NS presently include angiotensin converting enzyme inhibitors, angiotensin receptor blockers, monoclonal antibodies, steroids, and immunosuppresants. Steroids continue to be the initial treatment approach for NS patients and are considered as the foundation of the therapy. However, it is observed that about 50% of the patients with NS are steroid sensitive and therefore portray some response to steroids while the remainder are considered to be steroid-resistant and patients advance to end stage renal disease. As a result, the freight of morbidity becomes prodigious to patients and health services, specifically in the management of dialysis and transplantation. Although numerous studies have been done in the area of renal disorders, treatment of NS remains a critical challenge till date. This is due to the fact that the underlying mechanisms and causes are still not clearly understood. Therapies are now being refined and directed specifically to target the podocyte. In the recent past, histone deacetylase inhibitors (HDACi) have been greatly explored to treat chronic kidney diseases because of the anti-fibrotic, anti-inflammatory, and immunosuppressive effects that they exhibit. Histone deacetylases (HDACs) are the class of enzymes that remove the acetyl groups from the lysine amino acid on histone and thereby promote chromatin condensation and repression of transcription. HDACi are the chemical compounds that inhibit HDAC and alter gene transcription by inducing changes in the structure of proteins in transcription factor complexes. An irregular expression of HDACs has been noted that subsequently play a role in renal fibrosis and glomerulosclerosis associated with chronic renal conditions. Therefore, targeting HDACs can be a favourable therapeutic strategy to treat NS. In the present review, we outline the potential use of HDACi as therapeutic alternatives in treating NS. The promise of HDACi in NS is pragmatically put forth in this review.

P.760 Effects of novel cholinesterase inhibitors on mitochondrial respiration and MAO activity - in vitro study

Based on the lately identified role for the interstitial cells of Cajal (ICCs) of mouse prostate in catecholamine production, as well as the well-established role for the master coregulator metastasis-associated protein 1 (MTA1) in inflammation, we probed into the functional link between aberrant MTA1 expression and pathogenesis of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) using both a MTA1−/− mouse model of experimental autoimmune prostatitis (EAP) and an in vitro chronic prostatitis model in cultured murine ICCs. EAP-induced MTA1 expression was enriched in ICCs of mouse prostate. EAP resulted in a higher increase in the pelvic pain response in MTA1−/− mice compared to WT mice. Consistently, the ICCs from MTA1−/− mice produced higher levels of catecholamines upon induction of in vitro chronic prostatitis. Mechanistically, MTA1 could directly suppress the transcription of Aadc, a rate-limiting enzyme during catecholamine synthesis, in a HDAC2-depdendent manner. Importantly, treatment with AADC inhibitor NSD-1015 significantly ameliorated EAP-elicited pain response and catecholamine overactivity in MTA1−/− mice. Taken together, our findings reveal an inherent regulatory role of the MTA1/AADC pathway in the maintenance of catecholamine production homeostasis in prostate ICCs, and also point to a potential use of HDAC inhibitors and/or AADC inhibitors to treat CP/CPPS.

Histone Deacetylase Inhibition in Non-small Cell Lung Cancer: Hype or Hope?

Epigenetic modulation, including acetylation, methylation, phosphorylation, and ubiquitination, plays a pivotal role in regulation of gene expression. Histone acetylation—a balance between the activities of histone acetyltransferases (HATs) and histone deacetylases (HDACs)—is one of the key epigenetic events. Our understanding of the role of HDACs in cancer is evolving. A number of HDAC isoenzymes are overexpressed in a variety of malignancies. Aberrant histone acetylation is associated with dysregulation of tumor suppressor genes leading to development of several solid tumors and hematologic malignancies. Pre-clinical studies have demonstrated that HDAC-1 gene expression is associated with lung cancer progression. Histone hypoacetylation is associated with more aggressive phenotype in adenocarcinoma of the lung. HDAC inhibitors (HDACi) have pleiotropic cellular effects and induce the expression of pro-apoptotic genes/proteins, cause cellular differentiation and/or cell cycle arrest, inhibit angiogenesis, and inhibit transition to a mesenchymal phenotype. Consequently, treatment with HDACi has shown anti-proliferative activity in non-small cell lung cancer (NSCLC) cell lines. Despite promising results in pre-clinical studies, HDACi have shown only modest single agent activity in lung cancer clinical trials. HDAC activation has been implicated as one of the mechanisms causing resistance to chemotherapy, molecularly targeted therapy, and immune checkpoint inhibition. Therefore, there is a growing interest in combining HDACi with these agents to enhance their efficacy or reverse resistance. In this paper, we review the available preclinical and clinical evidence for the use of HDACi in NSCLC. We also review the challenges precluding widespread clinical utility of HDACi as a cancer therapy and future directions.

Histone Deacetylases and Histone Deacetylase Inhibitors in Neuroblastoma.

Histone deacetylases (HDACs) are enzymes that play a key role in regulating gene expression by remodeling chromatin structure. An imbalance of histone acetylation caused by deregulated HDAC expression and activity is known to promote tumor progression in a number of tumor types, including neuroblastoma, the most common solid tumor in children. Consequently, the inhibition of HDACs has emerged as a potential strategy to reverse these aberrant epigenetic changes, and several classes of HDAC inhibitors (HDACi) have been shown to inhibit tumor proliferation, or induce differentiation, apoptosis and cell cycle arrest in neuroblastoma. Further, the combined use of HDACi with other chemotherapy agents, or radiotherapy, has shown promising pre-clinical results and various HDACi have progressed to different stages in clinical trials. Despite this, the effects of HDACi are multifaceted and more work needs to be done to unravel their specific mechanisms of actions. In this review, we discuss the functional role of HDACs in neuroblastoma and the potential of HDACi to be optimized for development and use in the clinic for treatment of patients with neuroblastoma.

EPIGENETIC CHANGES IN MALIGNANT UVEAL MELANOMA AND POSSIBILITIES OF THEIR THERAPEUTIC TARGETING.

Uveal melanoma (UM) is a deadly cancer that leads to metastatic disease in more than 50 % of the patients. Despite the improvement in the treatment of primary disease, there is still no effective therapy to prevent the development of metastases. Therefore, the disease requires intensive research to identify new treatment strategies. In preclinical UM models, epigenetic drugs have been shown to increase the sensitivity of resistant tumour cells to treatment. The successful use of histone deacetylase inhibitors, which induced cell cycle arrest, reprogramming consistent with melanocyte differentiation and inhibition of tumour growth in preclinical models, demonstrates the role of epigenetic regulation in UM metastasis. Identification of epigenetic changes associated with UM development an progression could contribute to the discovery of more effective drugs that, in combination with traditional approaches, may yield better therapeutic results for high-risk patients.

Synergistic Enhancement of Cancer Therapy Using HDAC Inhibitors: Opportunity for Clinical Trials.

Chemotherapy is one of the most established and effective treatments for almost all types of cancer. However, the elevated toxicity due to the non-tumor-associated effects, development of secondary malignancies, infertility, radiation-induced fibrosis and resistance to treatment limit the effectiveness and safety of treatment. In addition, these multiple factors significantly impact quality of life. Over the last decades, our increased understanding of cancer epigenetics has led to new therapeutic approaches and the promise of improved patient outcomes. Epigenetic alterations are commonly found in cancer, especially the increased expression and activity of histone deacetylases (HDACs). Dysregulation of HDACs are critical to the development and progression of the majority of tumors. Hence, HDACs inhibitors (HDACis) were developed and now represent a very promising treatment strategy. The use of HDACis as monotherapy has shown very positive pre-clinical results, but clinical trials have had only limited success. However, combinatorial regimens with other cancer drugs have shown synergistic effects both in pre-clinical and clinical studies. At the same time, these combinations have enhanced the efficacy, reduced the toxicity and tumor resistance to therapy. In this review, we will examine examples of HDACis used in combination with other cancer drugs and highlight the synergistic effects observed in recent preclinical and clinical studies.

The combination of histone deacetylase inhibitors and radiotherapy: a promising novel approach for cancer treatment.

HDAC inhibitors (HDACi) play an essential role in various cellular processes, such as differentiation and transcriptional regulation of key genes and cytostatic factors, cell cycle arrest and apoptosis that facilitates the targeting of epigenome of eukaryotic cells. In the majority of cancers, only a handful of patients receive optimal benefit from chemotherapeutics. Additionally, there is emerging interest in the use of HDACi to modulate the effects of ionizing radiations. The use of HDACi with radiotherapy, with the goal of reaching dissimilar, often distinct pathways or multiple biological targets, with the expectation of synergistic effects, reduced toxicity and diminished intrinsic and acquired resistance, conveys an approach of increasing interest. In this review, the clinical potential of HDACi in combination with radiotherapy is described as an efficient synergy for cancer treatment will be overviewed.