Identification of PR-SET7 and EZH2 selective inhibitors inducing cell death in human leukemia U937 cells.

Chemical manipulations undertaken on some bis(bromo- and dibromo-phenol) compounds previously reported by us as wide-spectrum epigenetic inhibitors let us to identify bis (bromo- and dibromo-methoxyphenyl) derivatives highly selective for PR-SET7 and EZH2 (compounds 4, 5, 9, and 10). Western blot analyses were carried out in U937 cells to determine the effects of such compounds on the methyl marks related to the tested enzymes (H3K4me1, H3K9me2, H4H20me1, and H3K27me3). The 1,5-bis(3-bromo-4-methoxyphenyl)penta-1,4-dien-3-one 4 (EC(50) vs EZH2 = 74.

Highlights of the Keystone Symposium: sirtuins in metabolism, aging and disease.

From February 12-16, 2012, leading members of the sirtuin scientific community assembled in Tahoe, CA to attend the Keystone Symposium "Sirtuins in Aging, Metabolism, and Disease." It was a vibrant and lively meeting, and in the spirit of Keystone Symposia, both established sirtuin researchers and those new to the field enjoyed a unique opportunity to interact and exchange ideas.

2-(Alkyl/aryl)amino-6-benzylpyrimidin-4(3H)-ones as inhibitors of wild-type and mutant HIV-1: enantioselectivity studies.

The single enantiomers of two pyrimidine-based HIV-1 non-nucleoside reverse transcriptase inhibitors, 1 (MC1501) and 2 (MC2082), were tested in both cellular and enzyme assays. In general, the R forms were more potent than their S counterparts and racemates and (R)-2 was more efficient than (R)-1 and the reference compounds, with some exceptions. Interestingly, (R)-2 displayed a faster binding to K103N RT with respect to WT RT, while (R)-1 showed the opposite behavior.

An analog of BIX-01294 selectively inhibits a family of histone H3 lysine 9 Jumonji demethylases.

BIX-01294 and its analogs were originally identified and subsequently designed as potent inhibitors against histone H3 lysine 9 (H3K9) methyltransferases G9a and G9a-like protein. Here, we show that BIX-01294 and its analog E67 can also inhibit H3K9 Jumonji demethylase KIAA1718 with half-maximal inhibitory concentrations in low micromolar range. Crystallographic analysis of KIAA1718 Jumonji domain in complex with E67 indicated that the benzylated six-membered piperidine ring was disordered and exposed to solvent.

Novel reversible monoamine oxidase A inhibitors: highly potent and selective 3-(1H-pyrrol-3-yl)-2-oxazolidinones.

Monoamine oxidases (MAOs) are involved in various psychiatric and neurodegenerative disorders; hence, MAO inhibitors are useful agents in the therapy of Parkinson's disease, Alzheimer's dementia, and depression syndrome. Herein we report a novel series of 3-(1H-pyrrol-3-yl)-2-oxazolidinones 3-7 as reversible, highly potent and selective anti-MAO-A agents. In particular, 4b, 5b, and 4c showed a K(i-MAO-A) of 0.

Application of 3 μm particle-based amylose-derived chiral stationary phases for the enantioseparation of potential histone deacetylase inhibitors.

In this work, we report on the difference in performance of the two 3 μm particle-based Chiralpak IA-3 and Chiralpak AD-3 chiral stationary phases (CSPs) in the direct resolution of four racemic cinnamyl 2-aminoanilides, endowed with histone deacetylase inhibitory activity. The 3 μm CSPs were explored to determine if they could provide an effective resolution of enantiomers in presence of alcoholic eluents such as pure methanol, ethanol and 2-propanol. Temperature variable enantioselective HPLC and subsequent van't Hoff analysis were performed.

Screening assays for epigenetic targets using native histones as substrates.

In the past years, a lot of attention has been given to the identification and characterization of selective and potent inhibitors of chromatin-modifying enzymes to better understand their specific role in transcriptional regulation. As aberrant histone methylation is involved in different pathological processes, the search for methyltransferase and demethylase inhibitors has emerged as a crucial issue in current medicinal chemistry research. High-throughput in vitro assays are important tools for the identification of new methyltransferase or demethylase inhibitors.

Specific control of pancreatic endocrine β- and δ-cell mass by class IIa histone deacetylases HDAC4, HDAC5, and HDAC9.

Objective: Class IIa histone deacetylases (HDACs) belong to a large family of enzymes involved in protein deacetylation and play a role in regulating gene expression and cell differentiation. Previously, we showed that HDAC inhibitors modify the timing and determination of pancreatic cell fate. The aim of this study was to determine the role of class IIa HDACs in pancreas development.

Targeting Histone Demethylases: A New Avenue for the Fight against Cancer.

In addition to genetic disorders, epigenetic alterations have been shown to be involved in cancer, through misregulation of histone modifications. Miswriting, misreading, and mis-erasing of histone acetylation as well as methylation marks can be actually associated with oncogenesis and tumor proliferation. Historically, methylation of Arg and Lys residues has been considered a stable, irreversible process due to the slow turnover of methyl groups in chromatin.

Sirtinol treatment reduces inflammation in human dermal microvascular endothelial cells.

Histone deacetylases (HDAC) are key enzymes in the epigenetic control of gene expression. Recently, inhibitors of class I and class II HDAC have been successfully employed for the treatment of different inflammatory diseases such as rheumatoid arthritis, colitis, airway inflammation and asthma. So far, little is known so far about a similar therapeutic effect of inhibitors specifically directed against sirtuins, the class III HDAC.

Identification of small-molecule inhibitors of the XendoU endoribonucleases family.

The XendoU family of enzymes includes several proteins displaying high sequence homology. The members characterized so far are endoribonucleases sharing similar biochemical properties and a common architecture in their active sites. Despite their similarities, these proteins are involved in distinct RNA-processing pathways in different organisms.

Epigenetic modulation of PGC-1α activity by GCN5 inhibitors: WO2010007085.

The transcriptional peroxisome proliferator-activated receptor γ (PPARγ) co-activator PGC-1α plays a central role in the regulation of cellular energy metabolism. Among the wide range of its activities, PGC-1α controls mitochondrial biogenesis and function and is one of the main factors involved in hormonal and nutrient regulation of hepatic gluconeogenesis. PGC-1α is present in a multiprotein complex, and its activity can also be modulated through epigenetic modifications.

Modulation of cell differentiation, proliferation, and tumor growth by dihydrobenzyloxopyrimidine non-nucleoside reverse transcriptase inhibitors.

A series of 5-alkyl-2-(alkylthio)-6-(1-(2,6-difluorophenyl)propyl)-3,4-dihydropyrimidin-4(3H)-one derivatives (3a-h) belonging to the F(2)-DABOs class of non-nucleoside HIV-1 reverse transcriptase inhibitors (NNRTIs) are endowed with a strong antiproliferative effect and induce cytodifferentiation in A375 melanoma cells. Among tested compounds, the most potent is 3g (SPV122), which also induces apoptosis in a cell-density-dependent manner and antagonizes tumor growth in animal models. All these effects are similar or even more pronounced than those previously reported for other nucleoside or non-nucleoside inhibitors of reverse transcriptase or by functional knockout of the reverse-transcriptase-encoding long interspersed element 1 by RNA interference (RNAi).

A photoreactive small-molecule probe for 2-oxoglutarate oxygenases.

2-oxoglutarate (2-OG)-dependent oxygenases have diverse roles in human biology. The inhibition of several 2-OG oxygenases is being targeted for therapeutic intervention, including for cancer, anemia, and ischemic diseases. We report a small-molecule probe for 2-OG oxygenases that employs a hydroxyquinoline template coupled to a photoactivable crosslinking group and an affinity-purification tag.

HDAC4-regulated STAT1 activation mediates platinum resistance in ovarian cancer.

Ovarian cancer frequently acquires resistance to platinum chemotherapy, representing a major challenge for improving patient survival. Recent work suggests that resistant clones exist within a larger drug-sensitive cell population prior to chemotherapy, implying that resistance is selected for rather than generated by treatment. We sought to compare clinically derived, intrapatient paired models of initial platinum response and subsequent resistant relapse to define molecular determinants of evolved resistance.

Pharmacological inhibition of HDAC6 attenuates endothelial barrier dysfunction induced by thrombin.

Background: Endothelial barrier dysfunction (EBD) involves microtubule disassembly and enhanced cell contractility. Histone deacetylase 6 (HDAC6) deacetylates α-tubulin, and thereby destabilizes microtubules. This study investigates a role for HDAC6 in EBD.

Gold drug auranofin restricts the viral reservoir in the monkey AIDS model and induces containment of viral load following ART suspension.

Objectives: A small pool of long-lived memory CD4 T cells harboring the retroviral genome is one main obstacle to HIV eradication. We tested the impact of the gold compound, auranofin, on phenotype and viability of CD4 T cells in vitro, and on persistence of lentiviral reservoir cells in vivo.

Design: In-vitro and in-vivo study.

Diarylpyrimidine-dihydrobenzyloxopyrimidine hybrids: new, wide-spectrum anti-HIV-1 agents active at (sub)-nanomolar level.

Here, we describe a novel small series of non-nucleoside reverse transcriptase inhibitors (NNRTIs) that combine peculiar structural features of diarylpyrimidines (DAPYs) and dihydro-alkoxy-benzyl-oxopyrimidines (DABOs). These DAPY-DABO hybrids (1-4) showed a characteristic SAR profile and a nanomolar anti-HIV-1 activity at both enzymatic and cellular level. In particular, the two compounds 4d and 2d, with a (sub)nanomolar activity against wild-type and clinically relevant HIV-1 mutant strains, were selected as lead compounds for next optimization studies.

Discovery, synthesis, and pharmacological evaluation of spiropiperidine hydroxamic acid based derivatives as structurally novel histone deacetylase (HDAC) inhibitors.

New spiro[chromane-2,4'-piperidine] and spiro[benzofuran-2,4'-piperidine] hydroxamic acid derivatives as HDAC inhibitors have been identified by combining privileged structures with a hydroxamic acid moiety as zinc binding group. The compounds were evaluated for their ability to inhibit nuclear extract HDACs and for their in vitro antiproliferative activity on different tumor cell lines. This work resulted in the discovery of spirocycle 30d that shows good oral bioavailability and tumor growth inhibition in an HCT-116 murine xenograft model.

Novel cinnamyl hydroxyamides and 2-aminoanilides as histone deacetylase inhibitors: apoptotic induction and cytodifferentiation activity.

Four novel series of cinnamyl-containing histone deacetylase (HDAC) inhibitors 1-4 are described, containing hydroxamate (1 and 3) or 2-aminoanilide (2 and 4) derivatives. When screened against class I (maize HD1-B and human HDAC1) and class II (maize HD1-A and human HDAC4) HDACs, most hydroxamates and 2-aminoanilides displayed potent and selective inhibition toward class I enzymes. Immunoblotting analyses performed in U937 leukemia cells generally revealed high acetyl-H3 and low acetyl-α-tubulin levels.

Histone deacetylase inhibition modulates deoxyribonucleotide pools and enhances the antitumor effects of the ribonucleotide reductase inhibitor 3'-C-methyladenosine in leukaemia cells.

Histone deacetylase (HDAC) inhibitors are a new class of epigenetic agents that were reported to enhance the cytotoxic effects of classical anticancer drugs through multiple mechanisms. However, which of the possible drug combinations would be the most effective and clinically useful are to be determined. We treated the HL60 and NB4 promyelocytic leukaemia cells with a combination of the ribonucleotide reductase (RR) inhibitor 3'-C-methyladenosine (3'-Me-Ado) and several hydroxamic acid-derived HDAC inhibitors, including two recently synthesized molecules, MC1864 and MC1879, and the reference compound trichostatin A (TSA).