Optimization of Resveratrol Used as a Scaffold to Design Histone Deacetylase (HDAC-1 and HDAC-2) Inhibitors

Histone deacetylases (HDAC) are epigenetic enzymes responsible for repressing gene expression through the deacetylation of histone lysine residues. Therefore, inhibition of HDACs has become an interesting approach for the treatment of several diseases, including cancer, hematology, neurodegenerative, immune diseases, bacterial infections, and more. Resveratrol (RVT) has pleiotropic effects, including pan-inhibition of HDAC isoforms; however, its ability to interfere with membranes requires additional optimization to eliminate nonspecific and off-target effects. Thus, to explore RVT as a scaffold, we designed a series of novel HDAC-1 and -2 inhibitors containing the 2-aminobenzamide subunit. Using molecular modeling, all compounds, except unsaturated compounds (4) and (7), exhibited a similar mode of interaction at the active sites of HDAC 1 and 2. The docking score values obtained from the study ranged from −12.780 to −10.967 Kcal/mol. All compounds were synthesized, with overall yields ranging from 33% to 67.3%. In an initial screening, compounds (4), (5), (7), and (20)–(26), showed enzymatic inhibitory effects ranging from 1 to 96% and 6 to 93% against HDAC-1 and HDAC-2, respectively. Compound (5), the most promising HDAC inhibitor in this series, was selected for IC₅₀ assays, resulting in IC₅₀ values of 0.44 µM and 0.37 µM against HDAC-1 and HDAC-2, respectively. In a panel of selectivity against HDACs 3–11, compound (5) presented selectivity towards Class I, mainly HDAC-1, 2, and 3. All compounds exhibited suitable physicochemical and ADMET properties as determined using in silico simulations. In conclusion, the optimization of the RVT structure allows the design of selective HDAC inhibitors, mainly targeting HDAC-1 and HDAC-2 isoforms.

Synthesis and pharmacological evaluation of pomalidomide derivatives useful for sickle cell disease treatment

Fetal hemoglobin (HbF) induction constitutes a valuable and validated approach to treat the symptoms of sickle cell disease (SCD). Here, we synthesized pomalidomide-nitric oxide (NO) donor derivatives (3a-f) and evaluated their suitability as novel HbF inducers. All compounds demonstrated different capacities of releasing NO, ranging 0.3-30.3%. Compound 3d was the most effective HbF inducer for CD34+ cells, exhibiting an effect similar to that of hydroxyurea. We investigated the mode of action of compound 3d for HbF induction by studying the in vitro alterations in the levels of transcription factors (BCL11A, IKAROS, and LRF), inhibition of histone deacetylase enzymes (HDAC-1 and HDAC-2), and measurement of cGMP levels. Additionally, compound 3d exhibited a potent anti-inflammatory effect similar to that of pomalidomide by reducing the TNF-α levels in human mononuclear cells treated with lipopolysaccharides up to 58.6%. Chemical hydrolysis studies revealed that compound 3d was stable at pH 7.4 up to 24 h. These results suggest that compound 3d is a novel HbF inducer prototype with the potential to treat SCD symptoms.

Discovery of phenylsulfonylfuroxan derivatives as gamma globin inducers by histone acetylation

N-oxide derivatives 5(a-b), 8(a-b), and 11(a-c) were designed, synthesized and evaluated in vitro and in vivo as potential drugs that are able to ameliorate sickle cell disease (SCD) symptoms. All of the compounds demonstrated the capacity to releasing nitric oxide at different levels ranging from 0.8 to 30.1%, in vivo analgesic activity and ability to reduce TNF-α levels in the supernatants of monocyte cultures. The most active compound (8b) protected 50.1% against acetic acid-induced abdominal constrictions, while dipyrone, which was used as a control only protected 35%. Compounds 8a and 8b inhibited ADP-induced platelet aggregation by 84% and 76.1%, respectively. Both compounds increased γ-globin in K562 cells at 100 μM. The mechanisms involved in the γ-globin increase are related to the acetylation of histones H3 and H4 that is induced by these compounds. In vitro, the most promising compound (8b) was not cytotoxic, mutagenic and genotoxic.

Antiplatelet and antithrombotic activities of non-steroidal anti-inflammatory drugs containing an N-acyl hydrazone subunit

Nonsteroidal anti-inflammatory drugs (NSAIDs) 1–5 containing an N-acyl hydrazone subunit were prepared and their antiplatelet and antithrombotic activities assessed in vitro and in vivo. Compounds 1–5 inhibited the platelet aggregation induced by adenosine diphosphate and/or arachidonic acid, with inhibition rates of 18.0%–61.1% and 65.9%–87.3%, respectively. Compounds 1 and 5 were the most active compounds, inhibiting adenosine-diphosphate-induced platelet aggregation by 57.2% and 61.1%, respectively. The inhibitory rates for arachidonic-acid-induced platelet aggregation were similar for compound 2 (80.8%) and acetylsalicylic acid (ASA, 80%). After their oral administration to mice, compounds 1, 3, and 5 showed shorter mean bleeding times than ASA. Compounds 1 and 5 also protected against thromboembolic events, with survival rates of 40% and 33%, respectively, compared with 30% for ASA. In conclusion, these results indicate that these novel NSAIDs containing an NAH subunit may offer better antiplatelet and antithrombotic activities than ASA.