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Concept: Hydroxamic acid


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


In this study, the siderophore-producing characteristics and conditions of Bacillus sp. PZ-1 were investigated and the enhancement of siderophores on Pb uptake and translocation in Brassica juncea were determined. Results of single factor experiment showed that glucose, pH and Pb(NO3)2 could stimulate PZ-1 growth and siderophore production. The maximum siderophore production of 90.52% siderophore units was obtained by response surface methodology optimization at glucose concentration of 21.84 g/l, pH 6.18 and Pb(NO3)2 concentration of 245.04 μmol/l. The type of siderophore was hydroxamate and its concentration in the fermentation broth amounted to 32.24 μg/ml. Results of pot experiment indicated that the siderophores enhanced Brassica juncea to assimilate more Pb from soil with the uptake ratio from 1.04 to 2.74 and translocate more Pb from underground to overground with the TF values from 1.21 to 1.48. The results revealed that Bacillus sp. PZ-1 could produce abundant siderophores and might be potentially used to augment the phytoextraction of Pb from soil.

Concepts: Enzyme, Operations research, Response surface methodology, Mathematical optimization, Hydroxamic acid, Phytoremediation, Brassica juncea, Siderophore


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


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


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


Shewanella algae B516 produces avaroferrin, an asymmetric hydroxamate siderophore, which has been shown to inhibit swarming motility of Vibrio alginolyticus. We aimed to elucidate the biosynthesis of this siderophore and to investigate how S. algae coordinates the production of avaroferrin and its two symmetric counterparts. We reconstituted the reaction in vitro with the main enzyme AvbD and the putative biosynthetic precursors, and demonstrate that multispecificity of this enzyme results in the production of all three cyclic hydroxamate siderophores that were previously isolated as natural products from S. algae. Surprisingly, purified AvbD exhibited a clear preference for the larger cadaverine-derived substrate. In live cells, however, siderophore ratios are maximized toward avaroferrin production, and we demonstrate that these siderophore ratios are the result of a regulation on substrate pool level, which may allow rapid evolutionary adaptation to environmental changes. Our results thereby give insights into a unique evolutionary strategy toward metabolite diversity.

Concepts: Natural selection, Bacteria, Metabolism, Adenosine triphosphate, Vibrio, Vibrio alginolyticus, Hydroxamic acid, Siderophore


The use of readily available hydroxamic acids as reagents for chemoselective (ortho-amino)arylation of amides is presented in this manuscript. The reaction proceeds under metal-free mild conditions, displays a very broad scope and constitutes a direct entry for the metal-free attachment of aniline residues to carbonyl derivatives.

Concepts: Amine, Carbonyl, Amide, Vorinostat, Hydroxamic acid, Sigmatropic reaction, Rearrangement reactions, Antarafacial and suprafacial


We constructed novel HIV-1 fusion inhibitors that may overcome the current limitations of enfuvirtide, the first such therapeutic in this class. The three prototypes generated by the Dock-and-Lock (DNL) technology to comprise four copies of enfuvirtide tethered site-specifically to the Fc end of different humanized monoclonal antibodies potently neutralize primary isolates (both R5-tropic and X4-tropic), as well as T-cell-adapted strains of HIV-1 in vitro. All three prototypes show EC(50) values in the subnanomolar range, which are 10- to 100-fold lower than enfuvirtide and attainable whether or not the constitutive antibody targets HIV-1. The potential of such conjugates to purge latently infected cells was also demonstrated in a cell-to-cell viral inhibition assay by measuring their efficacy to inhibit the spread of HIV-1(LAI) from infected human peripheral blood mononuclear cells to Jurkat T cells over a period of 30 days following viral activation with 100 nM SAHA (suberoylanilide hydroxamic acid). The IgG-like half-life was not significantly different from that of the parental antibody, as shown by the mean serum concentration of one prototype in mice at 72 h. These encouraging results provide a rationale to develop further novel anti-HIV agents by coupling additional antibodies of interest with alternative HIV-inhibitors via recombinantly-produced, self-assembling, modules.

Concepts: HIV, Immune system, White blood cell, Blood, Monoclonal antibodies, Inhibitor, Vorinostat, Hydroxamic acid