Chromatin modifying agents - the cutting edge of anticancer therapy

The novel preventive effect of a Japanese ethical Kampo extract formulation TJ-90 (Seihaito) against cisplatin-induced nephrotoxicity

BACKGROUND AND PURPOSE

Chinese herbal medicine has been developed as the traditional Japanese Kampo medicine, and it has been widely used to cure various symptoms in clinical practice. However, only a few studies are currently available on the effect of the Kampo medicine on renal disease. Nephrotoxicity is one of major side effect of cisplatin, the first metal-based anticancer drug. In the present study, we examined the effect of the Kampo medicine against cisplatin-induced nephrotoxicity (CIN).

METHODS

First, we screened the ethical Kampo extract formulation having positive effect against CIN using HK-2 cells. Next, we examined the preventive action of the selected ethical Kampo extract formulation against CIN in vivo using a mouse model.

RESULTS

Cisplatin-induced cell death was significantly suppressed by TJ-43 (Rikkunshito) and TJ-90 (Seihaito); however, cisplatin-induced cleaved caspase-3 expression was inhibited only by TJ-90. In an in vivo mouse model of cisplatin-induced kidney injury with dysfunction and increased inflammatory cytokine expression, TJ-90 showed amelioration of these damaging effects. Cisplatin-induced apoptosis and superoxide production were inhibited by treatment with TJ-90. The expression of cleaved caspase-3, 4-hydroxynonenal, and MAPK phosphorylation increased after cisplatin administration, but decreased after the administration of TJ-90. Among 16 crude drug extracts present in Seihaito, Bamboo Culm (Chikujo in Japanese) inhibited cisplatin-induced cell death and cleaved caspase-3 expression in HK-2 cells. Moreover, the anti-tumor effect of cisplatin was not affected by TJ-90 co-treatment in cancer cell lines.

CONCLUSION

TJ-90 might have a novel preventive action against CIN through the suppression of inflammation, apoptosis, and oxidative stress without interfering with the anti-tumor effect of cisplatin. Collectively, these findings might contribute to innovations in supportive care for cancer treatment-related side effects.

Combination Treatment of p53-Null HL-60 cells with Histone Deacetylase Inhibitors and Chlorambucil Augments Apoptosis and Increases BCL6 and p21 Gene Expression

BACKGROUND

Treatment of hematological malignancies with conventional DNA-damaging drugs, such as chlorambucil (CLB), commonly results in p53-dependent chemo-resistance. Chromatin modifying agents, such as histone deacetylase inhibitors (HDACIs), sodium butyrate (NaBu) and trichostatin A (TSA), may reverse chemo-resistance by modulating the activity of chromatin remodeling enzymes and/or genes that control cell proliferation, differentiation and survival.

OBJECTIVE

This study examined the potential use of HDACIs and CLB combination therapies in an in vitro chemo-resistant leukemia model.

METHODS

The p53-null promyelocytic leukemia cell line, HL60, was used as an in vitro model of chemo-resistant leukemia. Drug cytotoxicity was determined by tetrazolium salt-based colorimetric assays and Annexin V/propidium iodide staining (flow cytometry). The level of mRNA expression of the chromatin modifying genes was measured by quantitative real-time PCR.

RESULTS

Micromolar concentrations of CLB combined with either NaBu or TSA triggered synergistic cytotoxic effects in HL-60 cells (p < 0.001). The effects of the combination treatments resulted in upregulated p21 gene expression (up to 59-fold; p<0.001) that preceded an increase in BCL6 gene expression (up to 20-fold; p < 0.001). Statistically significant but smaller magnitude changes (≤ 2-fold; p <0.05) were noted in the expression of other genes studied regardless of the treatment type.

CONCLUSION

The combination treatment of p53-null HL-60 cells with DNA-damaging agent CLB and HDACIs NaBu and TSA triggered additive to synergistic effects on apoptosis and upregulated BCL6 and p21 expression. These findings reveal BCL6 and p21 as potential targets of chemo-resistance for the development of anti-leukemic drugs.

The Epigenetics of Alzheimer's Disease: Factors and Therapeutic Implications

Alzheimer’s disease (AD) is a well-known neurodegenerative disorder that imposes a great burden on the world. The mechanisms of AD are not yet fully understood. Current insight into the role of epigenetics in the mechanism of AD focuses on DNA methylation, remodeling of chromatin, histone modifications and non-coding RNA regulation. This review summarizes the current state of knowledge regarding the role of epigenetics in AD and the possibilities for epigenetically based therapeutics. The general conclusion is that epigenetic mechanisms play a variety of crucial roles in the development of AD, and there are a number of viable possibilities for treatments based on modulating these effects, but significant advances in knowledge and technology will be needed to move these treatments from the bench to the bedside.

The Methylation Status of the Epigenome: Its Emerging Role in the Regulation of Tumor Angiogenesis and Tumor Growth, and Potential for Drug Targeting

Approximately 50 years ago, Judah Folkman raised the concept of inhibiting tumor angiogenesis for treating solid tumors. The development of anti-angiogenic drugs would decrease or even arrest tumor growth by restricting the delivery of oxygen and nutrient supplies, while at the same time display minimal toxic side effects to healthy tissues. Bevacizumab (Avastin)—a humanized monoclonal anti VEGF-A antibody—is now used as anti-angiogenic drug in several forms of cancers, yet with variable results. Recent years brought significant progresses in our understanding of the role of chromatin remodeling and epigenetic mechanisms in the regulation of angiogenesis and tumorigenesis. Many inhibitors of DNA methylation as well as of histone methylation, have been successfully tested in preclinical studies and some are currently undergoing evaluation in phase I, II or III clinical trials, either as cytostatic molecules—reducing the proliferation of cancerous cells—or as tumor angiogenesis inhibitors. In this review, we will focus on the methylation status of the vascular epigenome, based on the genomic DNA methylation patterns with DNA methylation being mainly transcriptionally repressive, and lysine/arginine histone post-translational modifications which either promote or repress the chromatin transcriptional state. Finally, we discuss the potential use of “epidrugs” in efficient control of tumor growth and tumor angiogenesis.

Differential effect of quercetin on cisplatin-induced toxicity in kidney and tumor tissues

Strategies to minimize the nephrotoxicity of platinated antineoplastics without affecting its antitumour efficacy are strongly necessary to improve the pharmacotoxicological profile of these drugs. The natural flavonoid quercetin has been shown to afford nephroprotection without affecting cisplatin antitumour effect. The purpose of the present study has been to assess the differential mechanisms of action of cisplatin and quercetin on kidney and tumour tissues that could explain these effects. Wistar rats bearing subcutaneous tumours were treated with cisplatin and quercetin (and the appropriate controls). Tumour size and renal function evolution was monitored during 6 days. Platinum and quercetin content were also determined in both tissues. All the parameters studied, including blood supply, inflammation, apoptosis, critical MAPK signaling and oxidative stress in the cisplatin-treated animals are almost normalized by quercetin in the kidneys, but unaffected in the tumours. Our results suggest that in a cancer model in vivo, the protection exerted by quercetin on cisplatin nephrotoxicity is related to its antioxidant, vascular, anti-inflammatory and antiapoptotic effects, but these properties do not affect the mechanisms responsible for the antitumour effect of cisplatin.

Pharmacological inhibition of arginine and lysine methyltransferases induces nuclear abnormalities and suppresses angiogenesis in human endothelial cells

Posttranslational modifications of histone tails can alter chromatin structure and regulate gene transcription. While recent studies implicate the lysine/arginine protein methyltransferases in the regulation of genes for endothelial metabolism, the role of AMI-1 and AMI-5 compounds in angiogenesis remains unknown. Here, we show that global inhibition of arginine and lysine histone methyltransferases (HMTs) by AMI-5 induced an angiostatic profile in human microvascular endothelial cells and human umbilical vein endothelial cells. Based on FACS analysis, we found that inhibition of HMTs significantly affects proliferation of endothelial cells, by suppressing cell cycle progression in the G₀/G₁ phase. Immunofluorescent studies of the endothelial cells replication pattern by 5-ethynyl-2'-deoxyuridine incorporation disclosed that AMI-5, and the arginine methyltransferase inhibitor AMI-1, induced heterochromatin formation and a number of nuclear abnormalities, such as formation of micronuclei (MNs) and nucleoplasmic bridges (NPBs), which are markers of chromosomal instability. In addition to the modification of the cell cycle machinery in response to AMIs treatment, also endothelial cells migration and capillary-like tube formation processes were significantly inhibited, implicating a stimulatory role of HMTs in angiogenesis.

Identification and characterization of small-molecule inhibitors of lysine acetyltransferases

Lysine acetyltransferases (KATs) acetylate various proteins including histones, transcription factors, metabolic enzymes, and other cellular substrates. Protein acetylation significantly impacts protein stability and function. Certain KATs such as p300 (KAT3B) are overexpressed in cancer cells and are linked to tumor progression and drug resistance. Thus, pharmacologic inhibition of KATs represents a new strategy for cancer therapy. Quantitative biochemical assays of KAT enzymatic activity have been developed and adapted for high-throughput screens of small-molecule compounds to discover specific KAT inhibitors. Such compounds are useful probes for understanding the cellular functions of these critical enzymes and importantly, they may be further developed as anticancer therapeutics. Here we describe a fluorescence-based KAT activity assay and cell-based validation of KAT inhibition by small-molecule compounds.

Histone deacetylase inhibitors potentiate photochemotherapy in cutaneous T-cell lymphoma MyLa cells

Cutaneous T cell lymphomas (CTCL) represent rare extranodal non-Hodgkin's lymphomas, which are characterised by pleomorphic skin lesions and distinct T-cell markers. CTCL is a relatively benign disease in its early stages, but survival rates decrease significantly with progression. Histone deacetylase inhibitors (HDACi) have recently emerged as a new class of targeted anticancer therapies for CTCL, which have been shown to induce growth inhibition, terminal differentiation and apoptosis in various cancers in vitro and in vivo. In addition to the intrinsic anticancer properties of HDACi, recent studies have demonstrated its ability to synergise with phototherapy. In particular, we examine the therapeutic potential of HDACi in combination with ultraviolet A (UV-A) phototherapy, employing a halogenated DNA minor groove binding ligand called UVASens as a photosensitiser. In vitro studies have demonstrated that UVASens is approximately 1000-fold more potent than current psoralens. The extreme photopotency of UVASens allows the use of lower radiation doses minimising the carcinogenic risks associated with the long-term use of phototherapy. Considering, previous findings using the photosensitiser UVASens and potential synergy of HDACi with phototherapy, it was hypothesised that HDACi will augment photochemotherapy-induced cytotoxicity in CTCL MyLa cells. The findings indicated that combinations of UVASens/UV-A photochemotherapy and HDACi significantly decreased cell viability and increased apoptosis and DNA double-strand breaks in MyLa cells.

Epigenetics of Alzheimer's disease and frontotemporal dementia

This article will review the recent advances in the understanding of the role of epigenetic modifications and the promise of future epigenetic therapy in neurodegenerative dementias, including Alzheimer's disease and frontotemporal dementia.

Conventional chemotherapy or hypomethylating agents for older patients with acute myeloid leukaemia?

Acute myeloid leukaemia (AML) is the second more frequent hematologic malignancy in developed countries and primarily affects older adults with a median age at diagnosis of 69 years. Given the progressive ageing of the general population, the incidence of the disease in elderly people is expected to further increase in the years to come. Along with cytogenetics at diagnosis, age represents the most relevant prognostic factor in AML, in that the outcome steadily declines with increasing age. Reasons for poor prognosis include more frequent unfavourable karyotype and other adverse biologic characteristics, such as high rates of expression of genes drug resistance related and high prevalence of secondary AML. Noticeably, as compared with young adults, poorer results in elderly patients have been reported within any cytogenetic and molecular prognostic subgroup, because of frequent comorbid diseases, which render many patients ineligible to intensive chemotherapy. Therefore, predictive models have been developed with the aim of achieving best therapeutic results avoiding unnecessary toxicity. Following conventional induction therapy, older AML patients have complete remission rates in the range of 45-65%, and fewer than 10% of them survive for a minimum of 5 years. On the other hand, hypomethylating agents, such as azacytidine and decitabine offer the possibility of long-term disease control without necessarily achieving complete remission and can represent a reasonable alternative to intensive chemotherapy. Either intensive chemotherapy or hypomethylating agents have lights and shadows, and the therapeutic selection is often influenced by physician's and patient's attitude rather than definite criteria. Research is progress in order to assess predictive biologic factors, which would help clinicians in the selection of patients who can take actual benefit from different therapeutic options.

Histone deacetylase inhibitors (HDACIs): multitargeted anticancer agents

Histone deacetylase (HDAC) inhibitors are an emerging class of therapeutics with potential as anticancer drugs. The rationale for developing HDAC inhibitors (and other chromatin-modifying agents) as anticancer therapies arose from the understanding that in addition to genetic mutations, epigenetic changes such as dysregulation of HDAC enzymes can alter phenotype and gene expression, disturb homeostasis, and contribute to neoplastic growth. The family of HDAC inhibitors is large and diverse. It includes a range of naturally occurring and synthetic compounds that differ in terms of structure, function, and specificity. HDAC inhibitors have multiple cell type-specific effects in vitro and in vivo, such as growth arrest, cell differentiation, and apoptosis in malignant cells. HDAC inhibitors have the potential to be used as monotherapies or in combination with other anticancer therapies. Currently, there are two HDAC inhibitors that have received approval from the US FDA for the treatment of cutaneous T-cell lymphoma: vorinostat (suberoylanilide hydroxamic acid, Zolinza) and depsipeptide (romidepsin, Istodax). More recently, depsipeptide has also gained FDA approval for the treatment of peripheral T-cell lymphoma. Many more clinical trials assessing the effects of various HDAC inhibitors on hematological and solid malignancies are currently being conducted. Despite the proven anticancer effects of particular HDAC inhibitors against certain cancers, many aspects of HDAC enzymes and HDAC inhibitors are still not fully understood. Increasing our understanding of the effects of HDAC inhibitors, their targets and mechanisms of action will be critical for the advancement of these drugs, especially to facilitate the rational design of HDAC inhibitors that are effective as antineoplastic agents. This review will discuss the use of HDAC inhibitors as multitargeted therapies for malignancy. Further, we outline the pharmacology and mechanisms of action of HDAC inhibitors while discussing the safety and efficacy of these compounds in clinical studies to date.

DNA methylation and cancer

Cancer has been considered a genetic disease with a wide array of well-characterized gene mutations and chromosomal abnormalities. Of late, aberrant epigenetic modifications have been elucidated in cancer, and together with genetic alterations, they have been helpful in understanding the complex traits observed in neoplasia. "Cancer Epigenetics" therefore has contributed substantially towards understanding the complexity and diversity of various cancers. However, the positioning of epigenetic events during cancer progression is still not clear, though there are some reports implicating aberrant epigenetic modifications in very early stages of cancer. Amongst the most studied aberrant epigenetic modifications are the DNA methylation differences at the promoter regions of genes affecting their expression. Hypomethylation mediated increased expression of oncogenes and hypermethylation mediated silencing of tumor suppressor genes are well known examples. This chapter also explores the correlation of DNA methylation and demethylation enzymes with cancer.

Combination therapy: histone deacetylase inhibitors and platinum-based chemotherapeutics for cancer

One of the most promising strategies to increase the efficacy of standard chemotherapy drugs is by combining them with low doses of histone deacetylases inhibitors (HDACis). Regarded as chemosensitizers, the addition of well-tolerated doses of HDACis to platinum-based chemotherapeutics has been proven in vitro and in vivo in recent studies for many cancer types and stages. In this review, we discuss the most commonly used combinations of histone deacetylase inhibitors and platinum based drugs in the context of their possible mechanisms, efficiency, efficacy, and related drawbacks in preclinical and clinical studies.

Molecular and Epigenetic Mechanisms of MLL in Human Leukemogenesis

Epigenetics is often defined as the study of heritable changes in gene expression or chromosome stability that don’t alter the underlying DNA sequence. Epigenetic changes are established through multiple mechanisms that include DNA methylation, non-coding RNAs and the covalent modification of specific residues on histone proteins. It is becoming clear not only that aberrant epigenetic changes are common in many human diseases such as leukemia, but that these changes by their very nature are malleable, and thus are amenable to treatment. Epigenetic based therapies have so far focused on the use of histone deacetylase (HDAC) inhibitors and DNA methyltransferase inhibitors, which tend to have more general and widespread effects on gene regulation in the cell. However, if a unique molecular pathway can be identified, diseases caused by epigenetic mechanisms are excellent candidates for the development of more targeted therapies that focus on specific gene targets, individual binding domains, or specific enzymatic activities. Designing effective targeted therapies depends on a clear understanding of the role of epigenetic mutations during disease progression. The Mixed Lineage Leukemia (MLL) protein is an example of a developmentally important protein that controls the epigenetic activation of gene targets in part by methylating histone 3 on lysine 4. MLL is required for normal development, but is also mutated in a subset of aggressive human leukemias and thus provides a useful model for studying the link between epigenetic cell memory and human disease. The most common MLL mutations are chromosome translocations that fuse the MLL gene in frame with partner genes creating novel fusion proteins. In this review, we summarize recent work that argues MLL fusion proteins could function through a single molecular pathway, but we also highlight important data that suggests instead that multiple independent mechanisms underlie MLL mediated leukemogenesis.

Influence of natural and synthetic histone deacetylase inhibitors on chromatin

SIGNIFICANCE

Histone deacetylase inhibitors (HDACIs) have emerged as a new class of anticancer therapeutics. The hydroxamic acid, suberoylanilide hydroxamic acid (Vorinostat, Zolinza™), and the cyclic peptide, depsipeptide (Romidepsin, Istodax™), were approved by the U.S. Food and Drug Administration (FDA) for the treatment of cutaneous T-cell lymphoma in 2006 and 2009, respectively. At least 15 HDACIs are currently undergoing clinical trials either alone or in combination with other therapeutic modalities for the treatment of numerous hematological and solid malignancies.

RECENT ADVANCES

The potential utility of HDACIs has been extended to nononcologic applications, including autoimmune disorders, inflammation, diseases of the central nervous system, and malaria.

CRITICAL ISSUES

Given the promise of HDACIs, there is growing interest in the potential of dietary compounds that possess HDAC inhibition activity. This review is focused on the identification of and recent findings with HDACIs from dietary, medicinal plant, and microbial sources. We discuss the mechanisms of action and clinical potential of natural HDACIs.

FUTURE DIRECTIONS

Apart from identification of further HDACI compounds from dietary sources, further research will be aimed at understanding the effects on gene regulation on lifetime exposure to these compounds. Another important issue that requires clarification.

γ-H2AX and other histone post-translational modifications in the clinic

Chromatin is a dynamic complex of DNA and proteins that regulates the flow of information from genome to end product. The efficient recognition and faithful repair of DNA damage, particularly double-strand damage, is essential for genomic stability and cellular homeostasis. Imperfect repair of DNA double-strand breaks (DSBs) can lead to oncogenesis. The efficient repair of DSBs relies in part on the rapid formation of foci of phosphorylated histone H2AX (γ-H2AX) at each break site, and the subsequent recruitment of repair factors. These foci can be visualized with appropriate antibodies, enabling low levels of DSB damage to be measured in samples obtained from patients. Such measurements are proving useful to optimize treatments involving ionizing radiation, to assay in vivo the efficiency of various drugs to induce DNA damage, and to help diagnose patients with a variety of syndromes involving elevated levels of γ-H2AX. We will survey the state of the art of utilizing γ-H2AX in clinical settings. We will also discuss possibilities with other histone post-translational modifications. The ability to measure in vivo the responses of individual patients to particular drugs and/or radiation may help optimize treatments and improve patient care. This article is part of a Special Issue entitled: Chromatin in time and space.

Controversies Surrounding the Potential Use of Histone Deacetylase Inhibitors for the Treatment of Asthma

Management of asthma with long-acting β2-adrenergic receptor agonists and corticosteroids is exceptionally effective for the majority of asthma patients. However, corticosteroid insensitivity or resistance remains a significant clinical problem for a significant proportion of patients, requiring the investigation of new potential therapeutics for asthma. Histone deacetylase inhibitors represent a different class of compounds that have been evaluated for their potential antiasthmatic effects. Although accumulating evidence is indicating beneficial effects in rodent models of allergic airways disease, the potential use of histone deacetylase inhibitors in asthma remains controversial given their mechanisms of action. The aim of this paper is to provide an overview of histone deacetylases and pharmacological modifiers of these enzymes. The discussion represents a balanced account of the emerging evidence indicating the beneficial effects of histone deacetylase inhibitors in inflammatory lung diseases. The potential problems associated with the use of this class of compounds in asthma are also carefully considered.

Potential of chromatin modifying compounds for the treatment of Alzheimer's disease

Alzheimer's disease is a very common progressive neurodegenerative disorder affecting the learning and memory centers in the brain. The hallmarks of disease are the accumulation of β-amyloid neuritic plaques and neurofibrillary tangles formed by abnormally phosphorylated tau protein. Alzheimer's disease is currently incurable and there is an intense interest in the development of new potential therapies. Chromatin modifying compounds such as sirtuin modulators and histone deacetylase inhibitors have been evaluated in models of Alzheimer's disease with some promising results. For example, the natural antioxidant and sirtuin 1 activator resveratrol has been shown to have beneficial effects in animal models of disease. Similarly, numerous histone deacetylase inhibitors including Trichostatin A, suberoylanilide hydroxamic acid, valproic acid and phenylbutyrate reduction have shown promising results in models of Alzheimer's disease. These beneficial effects include a reduction of β-amyloid production and stabilization of tau protein. In this review we provide an overview of the histone deacetylase enzymes, with a focus on enzymes that have been identified to have an important role in the pathobiology of Alzheimer's disease. Further, we discuss the potential for pharmacological intervention with chromatin modifying compounds that modulate histone deacetylase enzymes.

Overview of the Classical Histone Deacetylase Enzymes and Histone Deacetylase Inhibitors

The important role of histone deacetylase enzymes in regulating gene expression, cellular proliferation, and survival has made them attractive targets for the development of histone deacetylase inhibitors as anticancer drugs. Suberoylanilide hydroxamic acid (Vorinostat, Zolinza), a structural analogue of the prototypical Trichostatin A, was approved by the US Food and Drug Administration for the treatment of advanced cutaneous T-cell lymphoma in 2006. This was followed by approval of the cyclic peptide, depsipeptide (Romidepsin, Istodax) for the same disease in 2009. Currently numerous histone deacetylase inhibitors are undergoing preclinical and clinical trials for the treatment of hematological and solid malignancies. Most of these studies are focused on combinations of histone deacetylase inhibitors with other therapeutic modalities, particularly conventional chemotherapeutics and radiotherapy. The aim of this paper is to provide an overview of the classical histone deacetylase enzymes and histone deacetylase inhibitors with an emphasis on potential combination therapies.

Histone deacetylases and their role in asthma

OBJECTIVE

The aim of this article is to provide an overview of the classical histone deacetylase (HDAC) enzymes and HDAC inhibitors. The discussion is focused on the potential anti-asthmatic effects of this group of compounds.

METHODS

Medline was used with the search terms, "asthma and HDAC," "asthma and Trichostatin A," "asthma and valproic acid," "allergic airways disease and HDAC," "allergic airways disease and Trichostatin A," and "allergic airways disease and valproic acid." Manuscripts from the past decade were accessed. Historical literature dating from the 1960s was accessed for the use of anti-epileptics in the treatment of asthma.

RESULTS

Preliminary clinical trials with anti-epileptic drugs including the well-known HDAC inhibitor, valproic acid, have shown long-lasting anti-asthmatic effects providing the basis for the evaluation of this class of compounds in asthma. Studies using the prototypical HDAC inhibitor, Trichostatin A, in well-established murine models of allergic airways disease have also indicated beneficial effects.

CONCLUSION

Although the precise mechanisms are still controversial, inhibition of airway hyperresponsiveness and agonist-induced contraction as well as anti-inflammatory effects have been described for HDAC inhibitors in asthma.

Histone deacetylase inhibition and dietary short-chain Fatty acids

Changes in diet can also have dramatic effects on the composition of gut microbiota. Commensal bacteria of the gastrointestinal tract are critical regulators of health and disease by protecting against pathogen encounter whilst also maintaining immune tolerance to certain allergens. Moreover, consumption of fibre and vegetables typical of a non-Western diet generates substantial quantities of short-chain fatty acids (SCFAs) which have potent anti-inflammatory properties. Dietary interventions such as probiotic supplementation have been investigated for their pleiotropic effects on microbiota composition and immune function. Probiotics may restore intestinal dysbiosis and improve clinical disease through elevated SCFA levels in the intestine. Although the precise mechanisms by which such dietary factors mediate these effects, SCFA metabolites such as butyrate also function as histone deacetylase inhibitors (HDACi), that can act on the epigenome through chromatin remodeling changes. The aim of this review is to provide an overview of HDAC enzymes and to discuss the biological effects of HDACi. Further, we discuss the important relationship between diet and the balance between health and disease and how novel dietary interventions such as probiotics could be alternative approach for the prevention and/or treatment of chronic inflammatory disease through modulation of the intestinal microbiome.