Resveratrol-salicylate derivatives as selective DNMT3 inhibitors and anticancer agents

Natural Stilbenes: Their Role in Colorectal Cancer Prevention, DNA Methylation, and Therapy

The resistance of colorectal cancer (CRC) to conventional therapeutic modalities, such as radiation therapy and chemotherapy, along with the associated side effects, significantly limits effective anticancer strategies. Numerous epigenetic investigations have unveiled that naturally occurring stilbenes can modify or reverse abnormal epigenetic alterations, particularly aberrant DNA methylation status, offering potential avenues for preventing or treating CRC. By modulating the activity of the DNA methylation machinery components, phytochemicals may influence the various stages of CRC carcinogenesis through multiple molecular mechanisms. Several epigenetic studies, especially preclinical research, have highlighted the effective DNA methylation modulatory effects of stilbenes with minimal adverse effects on organisms, particularly in combination therapies for CRC. However, the available preclinical and clinical data regarding the effects of commonly encountered stilbenes against CRC are currently limited. Therefore, additional epigenetic research is warranted to explore the preventive potential of these phytochemicals in CRC development and to validate their therapeutic application in the prevention and treatment of CRC. This review aims to provide an overview of selected bioactive stilbenes as potential chemopreventive agents for CRC with a focus on their modulatory mechanisms of action, especially in targeting alterations in DNA methylation machinery in CRC.

Recent Updates on Epigenetic-Based Pharmacotherapy for Atherosclerosis

Atherosclerosis is one of the most dominant pathological processes responsible in cardiovascular diseases (CVD) caused by cholesterol accumulation accompanied by inflammation in the arteries which will subsequently lead to further complications, including myocardial infarction and stroke. Although the incidence of atherosclerosis is decreasing in some countries, it is still considered the leading cause of death worldwide. Atherosclerosis is a vascular pathological process that is chronically inflammatory and is characterized by the invasion of inflammatory cells and cytokines. Many reports have unraveled the pivotal roles of epigenetics such as DNA methylation, post-translational histone modifications, and non-coding RNAs (ncRNAs) in atherogenesis, which regulate the expression of numerous genes related to various responsible pathways. Many studies have been conducted to develop new therapeutical approaches based on epigenetic changes for combating atherosclerosis. This review elaborates on recent updates on the development of new atherosclerosis drugs whose mechanism of action is associated with the modulation of DNA methylation, posttranslational histone modifications, and ncRNA-based gene regulation.

Cracking a cancer code DNA methylation in epigenetic modification: an in-silico approach on efficacy assessment of Sri Lanka-oriented nutraceuticals

DNA methyltransferase (DNMTs) are essential epigenetic modifiers that play a critical role in gene regulation. These enzymes add a methyl group to cytosine's 5'-carbon, specifically within CpG dinucleotides, using S-adenosyl-L-methionine. Abnormal overexpression of DNMTs can alter the gene expression patterns and contribute to cancer development in the human body. Therefore, the inhibition of DNMT is a promising therapeutic approach to cancer treatment. This study was aimed to identify potential nutraceutical inhibitors from the Sri Lanka Flora database using computational methods, which provided an atomic-level description of the drug binding site and examined the interactions between nutraceuticals and amino acids of the DNMT enzyme. A series of nutraceuticals from Sri Lanka-oriented plants were selected and evaluated to assess their inhibitory effects on DNMT using absorption, distribution, metabolism, excretion and toxicity analysis, virtual screening, molecular docking, molecular dynamics simulation and trajectory analysis. Azacitidine, a DNMT inhibitor approved by the US Food and Drug Administration, was selected as a reference inhibitor. The complexes with more negative binding energies were selected and further assessed for their potency. Seven molecules were identified from 200 nutraceuticals, demonstrating significantly negative binding energies against the DNMT enzyme. Various trajectory analyses were conducted to investigate the stability of the DNMT enzyme. The results indicated that petchicine (NP#0003), ouregidione (NP#0011) and azacitidine increased the stability of the DNMT enzyme. Consequently, these two nutraceuticals showed inhibitory efficacies similar to azacitidine, making them potential candidates for therapeutic interventions targeting DNMT enzyme-related cancers. Additional bioassay testing is recommended to confirm the efficacies of these nutraceuticals and explore their applicability in clinical treatments.Communicated by Ramaswamy H. Sarma.

Effect of Withaferin-A, Withanone, and Caffeic Acid Phenethyl Ester on DNA Methyltransferases: Potential in Epigenetic Cancer Therapy

BACKGROUND

DNA methyltransferases (DNMTs) have been reported to be potential drug targets in various cancers. The major hurdle in inhibiting DNMTs is the lack of knowledge about different DNMTs and their role in the hypermethylation of gene promoters in cancer cells. Lack of information on specificity, stability, and higher toxicity of previously reported DNMT inhibitors is the major reason for inadequate epigenetic cancer therapy. DNMT1 and DNMT3A are the two DNMTs that are majorly overexpressed in cancers.

OBJECTIVE

In this study, we have presented computational and experimental analyses of the potential of some natural compounds, withaferin A (Wi-A), withanone (Wi-N), and caffeic acid phenethyl ester (CAPE), as DNMT inhibitors, in comparison to sinefungin (SFG), a known dual inhibitor of DNMT1 and DNMT3A.

METHODS

We used classical simulation methods, such as molecular docking and molecular dynamics simulations, to investigate the binding potential and properties of the test compounds with DNMT1 and DNMT3A. Cell culture-based assays were used to investigate the inactivation of DNMTs and the resulting hypomethylation of the p16INK4A promoter, a key tumour suppressor that is inactivated by hypermethylation in cancer cells, resulting in upregulation of its expression.

RESULTS

Among the three test compounds (Wi-A, Wi-N, and CAPE), Wi-A showed the highest binding affinity to both DNMT1 and DNMT3A; CAPE showed the highest affinity to DNMT3A, and Wi-N showed a moderate affinity interaction with both. The binding energies of Wi-A and CAPE were further compared with SFG. Expression analysis of DNMTs showed no difference between control and treated cells. Cell viability and p16INK4A expression analysis showed a dose-dependent decrease in viability, an increase in p16INK4A, and a stronger effect of Wi-A compared to Wi-N and CAPE.

CONCLUSION

The study demonstrated the differential binding ability of Wi-A, Wi-N, and CAPE to DNMT1 and DNMT3A, which was associated with their inactivation, leading to hypomethylation and desilencing of the p16INK4A tumour suppressor in cancer cells. The test compounds, particularly Wi-A, have the potential for cancer therapy.

Mechanistic Insights into Harmine-Mediated Inhibition of Human DNA Methyltransferases and Prostate Cancer Cell Growth

Mammalian DNA methyltransferases (DNMTs), including DNMT1, DNMT3A, and DNMT3B, are key DNA methylation enzymes and play important roles in gene expression regulation. Dysregulation of DNMTs is linked to various diseases and carcinogenesis, and therefore except for the two approved anticancer azanucleoside drugs, various non-nucleoside DNMT inhibitors have been identified and reported. However, the underlying mechanisms for the inhibitory activity of these non-nucleoside inhibitors still remain largely unknown. Here, we systematically tested and compared the inhibition activities of five non-nucleoside inhibitors toward the three human DNMTs. We found that harmine and nanaomycin A blocked the methyltransferase activity of DNMT3A and DNMT3B more efficiently than resveratrol, EGCG, and RG108. We further determined the crystal structure of harmine in complex with the catalytic domain of the DNMT3B-DNMT3L tetramer revealing that harmine binds at the adenine cavity of the SAM-binding pocket in DNMT3B. Our kinetics assays confirm that harmine competes with SAM to competitively inhibit DNMT3B-3L activity with a Ki of 6.6 μM. Cell-based studies further show that harmine treatment inhibits castration-resistant prostate cancer cell (CRPC) proliferation with an IC50 of ∼14 μM. The CPRC cells treated with harmine resulted in reactivating silenced hypermethylated genes compared to the untreated cells, and harmine cooperated with an androgen antagonist, bicalutamide, to effectively inhibit the proliferation of CRPC cells. Our study thus reveals, for the first time, the inhibitory mechanism of harmine on DNMTs and highlights new strategies for developing novel DNMT inhibitors for cancer treatment.

Fruit Extract, Rich in Polyphenols and Flavonoids, Modifies the Expression of DNMT and HDAC Genes Involved in Epigenetic Processes

Recently, the field of epigenetics has been intensively studied in relation to nutrition. In our study, the gene expression patterns of histone deacetylases (HDACs), which regulate the stability of histone proteins, and DNA methyltransferases (DNMTs), which regulate DNA methylation, were determined in mice. The animals were fed a human-equivalent dose of the aqueous extract of fruit seeds and peels, which is rich in flavonoids and polyphenols, for 28 days and then exposed to the carcinogen 7,12-dimethylbenz(a)anthracene (DMBA). The concentrations of trans-resveratrol and trans-piceid were determined in the consumed extract by HPLC and were 1.74 mg/L (SD 0.13 mg/L) and 2.37 mg/L (SD 0.32 mg/L), respectively, which corresponds to the consumption of 0.2-1 L of red wine, the main dietary source of resveratrol, in humans daily. Subsequently, 24 h after DMBA exposure, the expression patterns of the HDAC and DNMT genes in the liver and kidneys were determined by qRT-PCR. The DMBA-induced expression of the tested genes HDAC1, HDAC2, DNMT1, DNMT3A and DNMT3B was reduced in most cases by the extract. It has already been shown that inhibition of the DNMT and HDAC genes may delay cancer development and tumour progression. We hypothesise that the extract studied may exert chemopreventive effects.

The suppressive role of phytochemical-induced glutathione S-transferase Mu 2 in human urothelial carcinoma cells

Glutathione S-transferases (GSTs) belong to one class of phase 2 detoxification enzymes which are important in metabolism and/or detoxification of various electrophilic endogenous metabolites and xenobiotics. From the available database, we found that GSTM2 gene expression is lower in high stages of bladder urothelial carcinoma than in stage 1 and normal bladder tissue. GSTM2 overexpression retards invasion, migration and tumor sphere formation of bladder cancer cells. Analysis of GSTM2 promoter activity shows that one SP1 site located at - 48 to - 40 bp is important for GSTM2 gene expression in BFTC 905 cells. An SP1 inhibitor, mithramycin A, inhibits GSTM2 promoter activity and protein expression. SP1 overexpression also increases GSTM2 expression in BFTC 905 and 5637 cells. Eight potential phytochemicals were analyzed for GSTM2 promoter activation, and results indicated that baicalein, berberrubine, chalcone, curcumin, resveratrol, and wogonin can increase promoter activity. In endogenous GSTM2 expression, berberrubine and resveratrol activated GSTM2 mRNA and protein expression the most. A DNA methylation inhibitor, 5-aza-deoxycytidine, can decrease GSTM2 gene methylation level and then increase its gene expression; 50 μM berberrubine decreased the GSTM2 gene methylation level, providing a mechanism for activating GSTM2 gene expression. Berberrubine and resveratrol also increased SP1 protein expression as one of the mechanisms for GSTM2 gene expression. In summary, berberrubine and resveratrol activates GSTM2 expression which inhibits cell proliferation, migration, and invasion of bladder cancer cells. The GSTM2 expression mechanism is partially via SP1 activation, and the effect of berberrubine is also partly via DNA CpG demethylation.

Resveratrol ameliorates toxic effects of cadmium on placental development in mouse placenta and human trophoblast cells

BACKGROUND

Cadmium (Cd) is a common heavy metal pollutant. Prenatal exposure to Cd results in adverse effects on fetal development. Placental apoptosis, inflammation, and epigenetic disruption have been implicated in Cd-induced placental toxicity. Resveratrol (Res) is a naturally occurring polyphenol with anti-apoptotic, anti-inflammatory, and epigenetic regulatory activities. In present study, the effects of Res on placental toxicity induced by Cd were evaluated.

METHODS

Pregnant CD-1 mice were fed with base diet containing 0.2% Res started on gestational day 0 (GD0), and intraperitoneally injected with 4.5 mg/kg CdCl₂ or saline once on GD9. JEG-3 cells were treated with 20 μM Res for 24 hr in the absence or presence of 20 μM CdCl₂ for the second 12 hr. The fetal outcomes, the apoptosis in placenta and JEG-3 cells, the expression of inflammatory cytokines and chemokines including tumor necrosis factor-α (TNF-α), interferon-gamma (IFN-γ), monocyte chemoattractant protein 1 (MCP-1), macrophage inflammatory protein-2 (MIP-2) and chemokine (C-X-C motif) ligand 1 (KC), and expression of endoplasmic reticulum (ER) stress markers were evaluated. The expression and activities of DNA methyltransferase (DNMT), and the activation of Akt signaling pathway were detected.

RESULTS

Cd exposure resulted in decreased fetal weight and crown-rump length while Res ameliorated these outcomes. Res suppressed Cd-induced apoptosis in placenta and JEG-3 cells, and decreased Cd-induced expression of TNF-α, IFN-γ, MCP-1, MIP-2, and KC in placenta. Cd greatly increased ER stress in placenta in mice, which was partially ameliorated by Res treatment. Res decreased Cd-induced upregulation of DNMT activity and suppressed Cd-induced expression of DNMT3B. Res restored estradiol secretion, enhances activity and protein levels of SIRT1 and inhibited Cd-induced activation of Akt signaling pathway.

CONCLUSION

Res ameliorated Cd-induced placental toxicity and regulated DNMT3 expression and PI3K/Akt pathway activation.

Identification of potential target genes of non-small cell lung cancer in response to resveratrol treatment by bioinformatics analysis

Non-small cell lung cancer (NSCLC) is the most common type in lung cancer in the world, and it severely threatens the life of patients. Resveratrol has been reported to inhibit cancer. However, mechanisms of resveratrol inhibiting NSCLC were unclear. The aim of this study was to identify differentially expressed genes (DEGs) of NSCLC treated with resveratrol and reveal the potential targets of resveratrol in NSCLC. We obtained mRNA expression profiles of two datasets from the National Center for Biotechnology Information Gene Expression Omnibus (NCBI-GEO) and 271 DEGs were selected for further analysis. Data from STRING shown that 177 nodes and 342 edges were in the protein-protein interaction (PPI) network, and 10 hub genes (ANPEP, CD69, ITGAL, PECAM1, PTPRC, CD34, ITGA1, CCL2, SOX2, and EGFR) were identified by Cytoscape plus-in cytoHubba. Survival analysis revealed that NSCLC patients showing low expression of PECAM1, ANPEP, CD69, ITGAL, and PTPRC were associated with worse overall survival (OS) (P < 0.05), and high expression of SOX2 and EGFR was associated with worse OS for NSCLC patients (P < 0.05). Overall, we identified ANPEP, CD69, ITGAL, and PTPRC as potential candidate genes which were main effects of resveratrol on the treatment of NSCLC. ANPEP, ITGAL, CD69, and PTPRC are all clusters of differentiation (CD) antigens, might be the targets of resveratrol. The bioinformatic results suggested that the inhibitory effect of resveratrol on lung cancer may be related to the immune signaling pathway. Further studies are needed to validate these findings and to explore their functional mechanisms.

Impact of Stilbenes as Epigenetic Modulators of Breast Cancer Risk and Associated Biomarkers

With the recent advancement of genetic screening for testing susceptibility to mammary oncogenesis in women, the relevance of the gene−environment interaction has become progressively apparent in the context of aberrant gene expressions. Fetal exposure to external stressors, hormones, and nutrients, along with the inherited genome, impact its traits, including cancer susceptibility. Currently, there is increasing interest in the role of epigenetic biomarkers such as genomic methylation signatures, plasma microRNAs, and alterations in cell-signaling pathways in the diagnosis and primary prevention of breast cancer, as well as its prognosis. Polyphenols like natural stilbenes have been shown to be effective in chemoprevention by exerting cytotoxic effects that can stall cell proliferation. Besides possessing antioxidant properties against the DNA-damaging effects of reactive oxygen species, stilbenes have also been observed to modulate cell-signaling pathways. With the increasing trend of early-life screening for hereditary breast cancer risks, the potency of different phytochemicals in harnessing the epigenetic biomarkers of breast cancer risk demand more investigation. This review will explore means of exploiting the abilities of stilbenes in altering the underlying factors that influence breast cancer risk, as well as the appearance of associated biomarkers.

Natural Product-Based Hybrids as Potential Candidates for the Treatment of Cancer: Focus on Curcumin and Resveratrol

One of the main current strategies for cancer treatment is represented by combination chemotherapy. More recently, this strategy shifted to the "hybrid strategy", namely the designing of a new molecular entity containing two or more biologically active molecules and having superior features compared with the individual components. Moreover, the term "hybrid" has further extended to innovative drug delivery systems based on biocompatible nanomaterials and able to deliver one or more drugs to specific tissues or cells. At the same time, there is an increased interest in plant-derived polyphenols used as antitumoral drugs. The present review reports the most recent and intriguing research advances in the development of hybrids based on the polyphenols curcumin and resveratrol, which are known to act as multifunctional agents. We focused on two issues that are particularly interesting for the innovative chemical strategy involved in their development. On one hand, the pharmacophoric groups of these compounds have been used for the synthesis of new hybrid molecules. On the other hand, these polyphenols have been introduced into hybrid nanomaterials based on gold nanoparticles, which have many potential applications for both drug delivery and theranostics in chemotherapy.

Roles and Mechanisms of DNA Methylation in Vascular Aging and Related Diseases

Vascular aging is a pivotal risk factor promoting vascular dysfunction, the development and progression of vascular aging-related diseases. The structure and function of endothelial cells (ECs), vascular smooth muscle cells (VSMCs), fibroblasts, and macrophages are disrupted during the aging process, causing vascular cell senescence as well as vascular dysfunction. DNA methylation, an epigenetic mechanism, involves the alteration of gene transcription without changing the DNA sequence. It is a dynamically reversible process modulated by methyltransferases and demethyltransferases. Emerging evidence reveals that DNA methylation is implicated in the vascular aging process and plays a central role in regulating vascular aging-related diseases. In this review, we seek to clarify the mechanisms of DNA methylation in modulating ECs, VSMCs, fibroblasts, and macrophages functions and primarily focus on the connection between DNA methylation and vascular aging-related diseases. Therefore, we represent many vascular aging-related genes which are modulated by DNA methylation. Besides, we concentrate on the potential clinical application of DNA methylation to serve as a reliable diagnostic tool and DNA methylation-based therapeutic drugs for vascular aging-related diseases.

Resveratrol and other Stilbenes: Effects on Dysregulated Gene Expression in Cancers and Novel Delivery Systems

Trans-resveratrol (RESV), pterostilbene, trans-piceid and trans-viniferins are bioactive stilbenes present in grapes and other plants. Several groups applied biotechnology to introduce their synthesis in plant crops. Biochemical interaction with enzymes, regulation of non-coding RNAs, and activation of signaling pathways and transcription factors are among the main effects described in literature. However, solubility in ethanol, short half-life, metabolism by gut bacteria, make the concentration responsible for the effects observed in cultured cells difficult to achieve. Derivatives obtained by synthesis, trans-resveratrol analogs and methoxylated stilbenes show to be more stable and allow the synthesis of bioactive compounds with higher bioavailability. However, changes in chemical structure may require testing for toxicity. Thus, the delivery of RESV and its natural analogs incorporated into liposomes or nanoparticles, is the best choice to ensure stability during administration and appropriate absorption. The application of RESV and its derivatives with anti-inflammatory and anticancer activity is presented with description of novel clinical trials.

Expanding the Structural Diversity of DNA Methyltransferase Inhibitors

Inhibitors of DNA methyltransferases (DNMTs) are attractive compounds for epigenetic drug discovery. They are also chemical tools to understand the biochemistry of epigenetic processes. Herein, we report five distinct inhibitors of DNMT1 characterized in enzymatic inhibition assays that did not show activity with DNMT3B. It was concluded that the dietary component theaflavin is an inhibitor of DNMT1. Two additional novel inhibitors of DNMT1 are the approved drugs glyburide and panobinostat. The DNMT1 enzymatic inhibitory activity of panobinostat, a known pan inhibitor of histone deacetylases, agrees with experimental reports of its ability to reduce DNMT1 activity in liver cancer cell lines. Molecular docking of the active compounds with DNMT1, and re-scoring with the recently developed extended connectivity interaction features approach, led to an excellent agreement between the experimental IC₅₀ values and docking scores.

Resveratrol and Resveratrol-Aspirin Hybrid Compounds as Potent Intestinal Anti-Inflammatory and Anti-Tumor Drugs

Resveratrol (3,4,5-Trihydroxy-trans-stilbene) is a naturally occurring polyphenol that exhibits beneficial pleiotropic health effects. It is one of the most promising natural molecules in the prevention and treatment of chronic diseases and autoimmune disorders. One of the key limitations in the clinical use of resveratrol is its extensive metabolic processing to its glucuronides and sulfates. It has been estimated that around 75% of this polyphenol is excreted via feces and urine. To possibly alleviate the extensive metabolic processing and improve bioavailability, we have added segments of acetylsalicylic acid to resveratrol in an attempt to maintain the functional properties of both. We initially characterized resveratrol-aspirin derivatives as products that can inhibit cytochrome P450 Family 1 Subfamily A Member 1 (CYP1A1) activity, DNA methyltransferase (DNMT) activity, and cyclooxygenase (COX) activity. In this study, we provide a detailed analysis of how resveratrol and its aspirin derivatives can inhibit nuclear factor kappa B (NFκB) activation, cytokine production, the growth rate of cancer cells, and in vivo alleviate intestinal inflammation and tumor growth. We identified resveratrol derivatives C3 and C11 as closely preserving resveratrol bioactivities of growth inhibition of cancer cells, inhibition of NFκB activation, activation of sirtuin, and 5’ adenosine monophosphate-activated protein kinase (AMPK) activity. We speculate that the aspirin derivatives of resveratrol would be more metabolically stable, resulting in increased efficacy for treating immune disorders and as an anti-cancer agent.

Resveratrol ameliorates atherosclerosis induced by high-fat diet and LPS in ApoE-/- mice and inhibits the activation of CD4+ T cells

Background

Atherosclerosis (AS), which characterized with the accumulation of lipids on the vessel wall, is the pathological basis of many cardiovascular diseases (CVD) and seriously threatens human health. Resveratrol (RES) has been reported to be benefit for AS treatment. This research aimed to observe the effects of RES on AS induced by high-fat diet (HFD) and LPS in ApoE^-/- mice and investigate the underlying mechanism.

Methods

ApoE^-/- mice were fed with HFD companied with LPS to induce AS and RES was administrated for 20 weeks. Splenic CD4⁺ T cells were cultured and treated with anti-CD3/CD28 together with LPS, and RES was added. Serum lipids and the atherosclerotic areas of aortas were detected. The activation of CD4⁺ T cells were investigated both in vivo and in vitro and the expression of DNA methyltransferases (Dnmt) in CD4⁺ T cells were measured.

Results

In vivo, administration of RES prevented HFD and LPS induced dysfunction of serum lipids including TC (total cholesterol), TG (triglyceride), LDL-C (low density lipoprotein cholesterol) and HDL-C (high density lipoprotein cholesterol), ameliorated the thickened coronary artery wall and decreased the areas of atherosclerotic lesion on aortas. Besides, RES decreased the number of CD4⁺ T cells in peripheral blood, decreased the expression of CD25 and CD44, but not affected the expression of L-selectin (CD62L). In vitro, RES decreased the expression of Ki67, CD25 and CD44 in CD4⁺ T cells. Moreover, RES increased the secretion of IL-2, IL-10 and TGF-β1, decreased IL-6. In addition, RES decreased both the mRNA and protein level of Dnmt1 and Dnmt3b in CD4⁺ T cells.

Conclusion

These results indicated that RES ameliorated AS induced by HFD companied with LPS in ApoE^-/- mice, inhibited the proliferation and activation of CD4⁺ T cells and regulated the expression of Dnmt1 and Dnmt3b.

Resveratrol - A comprehensive review of recent advances in anticancer drug design and development

Resveratrol is a natural polyphenolic stilbene isolated from various plants, foods and beverages with a broad spectrum of biological and pharmacological properties through modulating diverse targets and signaling pathways. Particularly, it has attracted a great deal of attention as a promising and multitarget anticancer agent due to its potential use in chemoprevention and chemotherapy of various tumors. However, unfavorable pharmacokinetics/pharmacodynamics profile such as poor bioavailability restricted its applications. Therefore, medicinal chemists have synthesized a lot of novel derivatives and analogues of resveratrol using different modification strategies to overcome these limitations and improve anticancer efficacy. Herein, we reviewed the design, synthesis, structure-activity relationship and mechanism of the most potent and privileged resveratrol-based compounds that showed promising anticancer activities in the last five years. We classified these compounds into the ten different categories based on their chemical structure similarities.

Epigenetics, HIV, and Cardiovascular Disease Risk

Human immunodeficiency virus (HIV) is currently considered a risk factor for cardiovascular disease (CVD). With the advent of antiretroviral treatment and prevention, HIV-related morbidity and mortality rates have decreased significantly. Prolonged life expectancy heralded higher prevalence of diseases of aging, including CVD-associated morbidity and mortality, having an earlier onset in people living with HIV (PLHIV) compared to their noninfected counterparts. Several epigenetic biomarkers are now available as predictors of health and disease, with DNA methylation being one of the most widely studied. Epigenetic biomarkers are changes in gene expression without alterations to the intrinsic DNA sequence, with the potential to predict risk of future CVD, as well as the outcome and response to therapy among PLHIV. We sought to review the available literature referencing epigenetic markers to determine underlying biomechanism predisposing high-risk PLHIV to CVD, elucidating areas of possible intervention.

Resveratrol alleviates non-alcoholic fatty liver disease through epigenetic modification of the Nrf2 signaling pathway

Recent findings have demonstrated the aberrant DNA methylation of the Nrf2-Keap1 genes in human cancers; however, the epigenetic control of this pathway in non-alcoholic fatty liver disease (NAFLD) is unknown. Resveratrol can modify epigenetic mechanisms. Our objectives in this study were to explore the correlation between promoter methylation of the Nrf2-Keap1 genes and NAFLD, and that investigate the effect of resveratrol on the epigenetic regulation Nrf2-Keap1 in vitro and in vivo models of NAFLD. Resveratrol attenuated high fat-diet (HFD)-induced methylation of the Nrf2 promoter in the liver of mice, and this effect was correlated with reduction in triglyceride level and decrease in the expression of lipogenesis-related genes such as FAS and SREBP-1c. In addition, treatment of HepG2 cells with high glucose (HG) enhanced methylation level of the Nrf2 promoter, whereas resveratrol reversed this effect. Treatment of the cells with resveratrol or 5-aza, a demethylating agent, could prevent HG-induced reactive oxygen species production and expression of Nrf2-controlled antioxidant genes. Moreover, resveratrol or 5-aza could significantly attenuate HG-induced triglyceride accumulation in HepG2 cells. These findings indicate that resveratrol attenuates NAFLD through the epigenetic modification the Nrf2 signaling.

Cheminformatics Explorations of Natural Products

The chemistry of natural products is fascinating and has continuously attracted the attention of the scientific community for many reasons including, but not limited to, biosynthesis pathways, chemical diversity, the source of bioactive compounds and their marked impact on drug discovery. There is a broad range of experimental and computational techniques (molecular modeling and cheminformatics) that have evolved over the years and have assisted the investigation of natural products. Herein, we discuss cheminformatics strategies to explore the chemistry and applications of natural products. Since the potential synergisms between cheminformatics and natural products are vast, we will focus on three major aspects: (1) exploration of the chemical space of natural products to identify bioactive compounds, with emphasis on drug discovery; (2) assessment of the toxicity profile of natural products; and (3) diversity analysis of natural product collections and the design of chemical collections inspired by natural sources.

Rational Drug Design of Antineoplastic Agents Using 3D-QSAR, Cheminformatic, and Virtual Screening Approaches

Background:

Computer-Aided Drug Design has strongly accelerated the development of novel antineoplastic agents by helping in the hit identification, optimization, and evaluation.

Results:

Computational approaches such as cheminformatic search, virtual screening, pharmacophore modeling, molecular docking and dynamics have been developed and applied to explain the activity of bioactive molecules, design novel agents, increase the success rate of drug research, and decrease the total costs of drug discovery. Similarity, searches and virtual screening are used to identify molecules with an increased probability to interact with drug targets of interest, while the other computational approaches are applied for the design and evaluation of molecules with enhanced activity and improved safety profile.

Conclusion:

In this review are described the main in silico techniques used in rational drug design of antineoplastic agents and presented optimal combinations of computational methods for design of more efficient antineoplastic drugs.

Strategies to Improve Resveratrol Systemic and Topical Bioavailability: An Update

In recent years, a great deal of attention has been paid to natural compounds due to their many biological effects. Polyphenols are a class of plant derivatives that have been widely investigated for preventing and treating many oxidative stress-related pathological conditions, such as neurodegenerative and cardiovascular diseases, cancer, diabetes mellitus and inflammation. Among these polyphenols, resveratrol (RSV) has attracted considerable interest owing to its high antioxidant and free radical scavenging activities. However, the poor water solubility and rapid metabolism of RSV lead to low bioavailability, thus limiting its clinical efficacy. After discussing the main biochemical mechanisms involved in RSV biological activities, this review will focus on the strategies attempted to improve RSV effectiveness, both for systemic and for topical administration. In particular, technological approaches involving RSV incorporation into different delivery systems such as liposomes, polymeric and lipid nanoparticles, microemulsions and cyclodextrins will be illustrated, highlighting their potential clinical applications. In addition, chemical modifications of this antioxidant aimed at improving its physicochemical properties will be described along with the results of in vitro and in vivo studies.

Epigenetic modification of Nrf2 by sulforaphane increases the antioxidative and anti-inflammatory capacity in a cellular model of Alzheimer's disease

Sulforaphane was reported to exert neuroprotective effects via upregulating expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and has received increasing attention as an alternative candidate for treatment of Alzheimer's disease (AD). However, the mechanism to account for Nrf2 upregulation by sulforaphane in AD remains unknown. Herein, we found that sulforaphane upregulated Nrf2 expression and promoted Nrf2 nuclear translocation via decreasing DNA methylation levels of the Nrf2 promoter in mouse neuroblastoma N2a cells stably expressing human Swedish mutant amyloid precursor protein (N2a/APPswe cells), a cellular model of AD. Furthermore, sulforaphane (1.25 and 2.5 μM) decreased the levels of amyloid β 1-40 (Aβ_1-40) (21.7% and 33.4% decrease for intracellular Aβ_1-40; 22.0% and 30.2% decrease in culture medium), Aβ_1-42 (26.4% and 42.9% decrease for intracellular Aβ_1-42; 25.8% and 43.8% decrease in culture medium), reactive oxygen species (15.0% and 28.5% decrease), and malondialdehyde (MDA) (34.4% and 39.2% decrease) and increased superoxide dismutase (SOD) (60.0% and 89.3% increase) activity in N2a/APPswe cells. Sulforaphane also decreased the levels of pro-inflammatory cytokines interleukin 1β (IL-1β) (16.5% and 33.6% decrease) and IL-6 (15.6% and 26.1% decrease) and reduced phosphorylated nuclear factor-κB (NF-κB) p65 (19.2% and 32.2% decrease), cyclooxygenase-2 (COX-2) (20.5% and 28.6% decrease), and iNOS protein (40.2% and 54.7% decrease) expression levels in N2a/APPswe cells. Our study suggested that sulforaphane upregulated the expression of Nrf2 and promoted the nuclear translocation of Nrf2 by decreasing DNA demethylation levels of the Nrf2 promoter, thus leading to antioxidative and anti-inflammatory effects in a cellular model of AD.

The Impact of Environmental Factors in Influencing Epigenetics Related to Oxidative States in the Cardiovascular System

Oxidative states exert a significant influence on a wide range of biological and molecular processes and functions. When their balance is shifted towards enhanced amounts of free radicals, pathological phenomena can occur, as the generation of reactive oxygen species (ROS) in tissue microenvironment or in the systemic circulation can be detrimental. Epidemic chronic diseases of western societies, such as cardiovascular disease, obesity, and diabetes correlate with the imbalance of redox homeostasis. Current advances in our understanding of epigenetics have revealed a parallel scenario showing the influence of oxidative stress as a major regulator of epigenetic gene regulation via modification of DNA methylation, histones, and microRNAs. This has provided both the biological link and a potential molecular explanation between oxidative stress and cardiovascular/metabolic phenomena. Accordingly, in this review, we will provide current insights on the physiological and pathological impact of changes in oxidative states on cardiovascular disorders, by specifically focusing on the influence of epigenetic regulation. A special emphasis will highlight the effect on epigenetic regulation of human's current life habits, external and environmental factors, including food intake, tobacco, air pollution, and antioxidant-based approaches. Additionally, the strategy to quantify oxidative states in humans in order to determine which biological marker could best match a subject's profile will be discussed.

Cancer Chemoprevention by Phytochemicals: Nature's Healing Touch

Phytochemicals are an important part of traditional medicine and have been investigated in detail for possible inclusion in modern medicine as well. These compounds often serve as the backbone for the synthesis of novel therapeutic agents. For many years, phytochemicals have demonstrated encouraging activity against various human cancer models in pre-clinical assays. Here, we discuss select phytochemicals—curcumin, epigallocatechin-3-gallate (EGCG), resveratrol, plumbagin and honokiol—in the context of their reported effects on the processes of inflammation and oxidative stress, which play a key role in tumorigenesis. We also discuss the emerging evidence on modulation of tumor microenvironment by these phytochemicals which can possibly define their cancer-specific action. Finally, we provide recent updates on how low bioavailability, a major concern with phytochemicals, is being circumvented and the general efficacy being improved, by synthesis of novel chemical analogs and nanoformulations.

DNA Methylation Targeting: The DNMT/HMT Crosstalk Challenge

Chromatin can adopt a decondensed state linked to gene transcription (euchromatin) and a condensed state linked to transcriptional repression (heterochromatin). These states are controlled by epigenetic modulators that are active on either the DNA or the histones and are tightly associated to each other. Methylation of both DNA and histones is involved in either the activation or silencing of genes and their crosstalk. Since DNA/histone methylation patterns are altered in cancers, molecules that target these modifications are interesting therapeutic tools. We present herein a vast panel of DNA methyltransferase inhibitors classified according to their mechanism, as well as selected histone methyltransferase inhibitors sharing a common mode of action.

DNMT3B in vitro knocking-down is able to reverse embryonal rhabdomyosarcoma cell phenotype through inhibition of proliferation and induction of myogenic differentiation

Aberrant DNA methylation has been frequently observed in many human cancers, including rhabdomyosarcoma (RMS), the most common soft tissue sarcoma in children. To date, the expression and function of the de novo DNA methyltransferase (DNMT) 3B in RMS have not yet been investigated. Our study show for the first time a significant up-regulation of DNMT3B levels in 14 RMS tumour samples and 4 RMS cell lines in comparison to normal skeletal muscle. Transfection of RD and TE671 cells, two in vitro models of embryonal RMS (ERMS), with a synthetic DNMT3B siRNA decreased cell proliferation by arresting cell cycle at G1 phase, as demonstrated by the reduced expression of Cyclin B1, Cyclin D1 and Cyclin E2, and by the concomitant up-regulation of the checkpoint regulators p21 and p27. DNMT3B depletion also impaired RB phosphorylation status and decreased migratory capacity and clonogenic potential. Interestingly, DNMT3B knock-down was able to commit ERMS cells towards myogenic terminal differentiation, as confirmed by the acquisition of a myogenic-like phenotype and by the increased expression of the myogenic markers MYOD1, Myogenin and MyHC. Finally, inhibition of MEK/ERK signalling by U0126 resulted in a reduction of DNMT3B protein, giving evidence that DNMT3B is a down-stream molecule of this oncogenic pathway.Taken together, our data indicate that altered expression of DNMT3B plays a key role in ERMS development since its silencing is able to reverse cell cancer phenotype by rescuing myogenic program. Epigenetic therapy, by targeting the DNA methylation machinery, may represent a novel therapeutic strategy against RMS.

Treatment of cardiovascular pathology with epigenetically active agents: Focus on natural and synthetic inhibitors of DNA methylation and histone deacetylation

Cardiovascular disease (CVD) retains a leadership as a major cause of human death worldwide. Although a substantial progress was attained in the development of cardioprotective and vasculoprotective drugs, a search for new efficient therapeutic strategies and promising targets is under way. Modulation of epigenetic CVD mechanisms through administration epigenetically active agents is one of such new approaches. Epigenetic mechanisms involve heritable changes in gene expression that are not linked to the alteration of DNA sequence. Pathogenesis of CVDs is associated with global genome-wide changes in DNA methylation and histone modifications. Epigenetically active compounds that influence activity of epigenetic modulators such as DNA methyltransferases (DNMTs), histone acetyltransferases, histone deacetylases (HDACs), etc. may correct these pathogenic changes in the epigenome and therefore be used for CVD therapy. To date, many epigenetically active natural substances (such as polyphenols and flavonoids) and synthetic compounds such as DNMT inhibitors or HDAC inhibitors are known. Both native and chemical DNMT and HDAC inhibitors possess a wide range of cytoprotective activities such as anti-inflammatory, antioxidant, anti-apoptotic, anti-anfibrotic, and anti-hypertrophic properties, which are beneficial of treatment of a variety of CVDs. However, so far, only synthetic DNMT inhibitors enter clinical trials while synthetic HDAC inhibitors are still under evaluation in preclinical studies. In this review, we consider epigenetic mechanisms such as DNA methylation and histone modifications in cardiovascular pathology and the epigenetics-based therapeutic approaches focused on the implementation of DNMT and HDAC inhibitors.

Molecular Modeling and Chemoinformatics to Advance the Development of Modulators of Epigenetic Targets: A Focus on DNA Methyltransferases

In light of the emerging field of Epi-informatics, ie, computational methods applied to epigenetic research, molecular docking, and dynamics, pharmacophore and activity landscape modeling and QSAR play a key role in the development of modulators of DNA methyltransferases (DNMTs), one of the major epigenetic target families. The increased chemical information available for modulators of DNMTs has opened up the avenue to explore the epigenetic relevant chemical space (ERCS). Herein, we discuss recent progress on the identification and development of inhibitors of DNMTs as potential epi-drugs and epi-probes that have been driven by molecular modeling and chemoinformatics methods. We also survey advances on the elucidation of their structure-activity relationships and exploration of ERCS. Finally, it is illustrated how computational approaches can be applied to identify modulators of DNMTs in food chemicals.