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Concept: Vorinostat


Increasing evidence shows that the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA) possesses potent anti-inflammatory and immunomodulatory properties. It is tempting to evaluate the potential of SAHA as a therapeutic agent in various neuroinflammatory and neurodegenerative disorders.

Concepts: Histone deacetylase, Neuroscience, Neurology, Vorinostat, Histone deacetylase inhibitor, Trichostatin A, Hydroxamic acid, Hydroxamic acids


Despite antiretroviral therapy, proviral latency of human immunodeficiency virus type 1 (HIV-1) remains a principal obstacle to curing the infection. Inducing the expression of latent genomes within resting CD4(+) T cells is the primary strategy to clear this reservoir. Although histone deacetylase inhibitors such as suberoylanilide hydroxamic acid (also known as vorinostat, VOR) can disrupt HIV-1 latency in vitro, the utility of this approach has never been directly proven in a translational clinical study of HIV-infected patients. Here we isolated the circulating resting CD4(+) T cells of patients in whom viraemia was fully suppressed by antiretroviral therapy, and directly studied the effect of VOR on this latent reservoir. In each of eight patients, a single dose of VOR increased both biomarkers of cellular acetylation, and simultaneously induced an increase in HIV RNA expression in resting CD4(+) cells (mean increase, 4.8-fold). This demonstrates that a molecular mechanism known to enforce HIV latency can be therapeutically targeted in humans, provides proof-of-concept for histone deacetylase inhibitors as a therapeutic class, and defines a precise approach to test novel strategies to attack and eradicate latent HIV infection directly.

Concepts: Antiretroviral drug, HIV, AIDS, Gene, Histone deacetylase, Genome, Vorinostat, Histone deacetylase inhibitor


The genome-wide hyperacetylation of chromatin caused by histone deacetylase inhibitors (HDACi) is surprisingly well tolerated by most eukaryotic cells. The homeostatic mechanisms that underlie this tolerance are unknown. Here we identify the transcriptional and epigenomic changes that constitute the earliest response of human lymphoblastoid cells to two HDACi, valproic acid and suberoylanilide hydroxamic acid (Vorinostat), both in widespread clinical use.

Concepts: DNA, Histone, Histone deacetylase, Chromosome, Vorinostat, Histone deacetylase inhibitor, Trichostatin A, Hydroxamic acid


Abstract Since the first histone deacetylase (HDAC) inhibitor (Zolinza®, widely known as suberoylanilide hydroxamic acid; SAHA) was approved by the Food and Drug Administration for the treatment of T-cell lymphoma in 2006, the search for newer HDAC inhibitors has attracted a great deal of interest of medicinal chemists worldwide. As a continuity of our ongoing research in this area, we designed and synthesized a series of 5-substitutedphenyl-1,3,4-thiadiazole-based hydroxamic acids as analogues of SAHA and evaluated their biological activities. A number of compounds in this series, for example, N(1)-hydroxy-N(8)-(5-(2-chlorophenyl)-1,3,4-thiadiazol-2-yl)octandiamide (5b), N(1)-hydroxy-N(8)-(5-(3-chlorophenyl-1,3,4-thiadiazol-2-yl)octandiamide (5c) and N(1)-hydroxy-N(8)-(5-(4-chlorophenyl)-1,3,4-thiadiazol-2-yl)octandiamide (5d), were found to possess potent anticancer cytotoxicity and HDAC inhibition effects. Compounds 5b-d were generally two- to five-fold more potent in terms of cytotoxicity compared to SAHA against five cancer cell lines tested. Docking studies revealed that these hydroxamic acid displayed higher affinities than SAHA toward HDAC8.

Concepts: Cancer, Histone deacetylase, Lymphoma, Enzyme inhibitor, Vorinostat, Histone deacetylase inhibitor, Trichostatin A, Hydroxamic acid


We disclose the first small molecule histone deacetylase (HDAC) inhibitor (3, BRD73954) capable of potently and selectively inhibiting both HDAC6 and HDAC8 despite the fact that these isoforms belong to distinct phylogenetic classes within the HDAC family of enzymes. Our data demonstrate that meta substituents of phenyl hydroxamic acids are readily accommodated upon binding to HDAC6, and furthermore, are necessary for the potent inhibition of HDAC8.

Concepts: Histone deacetylase, Enzyme inhibitor, Inhibitor, Xanthine oxidase inhibitor, Acetylation, Vorinostat, HDAC6, EC 3.5.1


Arrangement of several hydroxamic acid-derived substituents along the cavity of a cyclodextrin ring leads to compounds that detoxify tabun in TRIS-HCl buffer at physiological pH and 37.0 °C with half-times as low as 3 min.

Concepts: Acid, Acid dissociation constant, PH, Buffer solution, Vorinostat, Bicarbonate, Cyclodextrin, Hydroxamic acid


To improve the bioavailability and anticancer potential of suberoylanilide hydroxamic acid (SAHA) by developing a drug-loaded polymeric nanomicellar system.

Concepts: In vivo, In vitro fertilisation, In vitro, Vorinostat, Hydroxamic acid, Hydroxamic acids


The histone deacetylase (HDAC) inhibitor vorinostat (VOR) can increase HIV RNA expression in vivo within resting CD4+ T cells of aviremic HIV+ individuals. However, while studies of VOR or other HDAC inhibitors have reported reversal of latency, none has demonstrated clearance of latent infection. We sought to identify the optimal dosing of VOR for effective serial reversal of HIV latency.

Concepts: HIV, Gene, Histone deacetylase, Vorinostat, Histone deacetylase inhibitor, HDAC1, Valproic acid, Trichostatin A


A novel strategy to treat anxiety and fear-related disorders such as phobias, panic and PTSD (post-traumatic stress disorder) is combining CBT (cognitive behavioural therapy), including extinction-based exposure therapy, with cognitive enhancers. By targeting and boosting mechanisms underlying learning, drug development in this field aims at designing CBT-augmenting compounds that help to overcome extinction learning deficits, promote long-term fear inhibition and thus support relapse prevention. Progress in revealing the role of epigenetic regulation of specific genes associated with extinction memory generation has opened new avenues in this direction. The present review examines recent evidence from pre-clinical studies showing that increasing histone acetylation, either via genetic or pharmacological inhibition of HDACs (histone deacetylases) by e.g. vorinostat/SAHA (suberoylanilide hydroxamic acid), entinostat/MS-275, sodium butyrate, TSA (trichostatin A) or VPA (valproic acid), or by targeting HATs (histone acetyltransferases), augments fear extinction and, importantly, generates a long-term extinction memory that can protect from return of fear phenomena. The molecular mechanisms and pathways involved including BDNF (brain-derived neurotrophic factor) and NMDA (N-methyl-D-aspartate) receptor signalling are just beginning to be revealed. First studies in healthy humans are in support of extinction-facilitating effects of HDAC inhibitors. Very recent evidence that HDAC inhibitors can rescue deficits in extinction-memory-impaired rodents indicates a potential clinical utility of this approach also for exposure therapy-resistant patients. Important future work includes investigation of the long-term safety aspects of HDAC inhibitor treatment, as well as design of isotype(s)-specific inhibitors. Taken together, HDAC inhibitors display promising potential as pharmacological adjuncts to augment the efficacy of exposure-based approaches in anxiety and trauma therapy.

Concepts: Histone, Histone deacetylase, Cognitive behavioral therapy, Acetylation, Vorinostat, Histone deacetylase inhibitor, Histone acetyltransferase, Trichostatin A


Single-agent post-autologous transplant maintenance therapy with lenalidomide is standard of care for patients with multiple myeloma. The tolerability and effectiveness of combination post-transplant maintenance therapy is unknown, so we investigated lenalidomide and vorinostat (suberoylanilide hydroxamic acid) in this setting, hypothesizing that the regimen would be well tolerated and associated with an improved post-transplant response. This trial followed a standard 3 × 3 dose escalation phase 1 design. Vorinostat was administered beginning day +90 post-haematopoietic stem cell transplantation for days 1-7 and 15-21, and lenalidomide was started at 10 mg days 1-21, both on a 28-d cycle. The primary endpoint was maximum tolerated dose and dose limiting toxicities were assessed during the first cycle. Treatment was well tolerated in 16 enrolled patients. During Cycle 1, the most common toxicities included cytopenias, gastrointestinal complaints and fatigue. Seven patients improved their transplant response after starting combination therapy. The median follow-up was 38·4 months, and the median progression-free survival and overall survival have yet to be reached. This oral post-transplant maintenance regimen was well tolerated. This is the first trial to publish results on the use of a histone deacetylase inhibitor in the maintenance setting, and it provides rationale for the ongoing randomized trial in maintenance (ISRCTN 49407852).

Concepts: Multiple myeloma, Histone deacetylase, Vorinostat, Histone deacetylase inhibitor, Trichostatin A, Hydroxamic acid, Hydroxamic acids