Novel berberine derivatives as p300 histone acetyltransferase inhibitors in combination treatment for breast cancer.

Adenoviral E1A binding protein p300 (EP300 or p300) and its similar paralog, cyclic-AMP response element binding protein (CBP), are important histone acetyltransferases (HAT) and transcriptional co-activators in epigenetics, participating in numerous cellular pathways including proliferation, differentiation and apoptosis. The overexpression or dysregulation of p300/CBP is closely related to oncology-relevant disease. The inhibition of p300 HAT has been found to be a potential drug target. Berberine has been reported to show anticancer activity and synergistic effect in combination with some of the clinical anticancer drugs via modulation of various pathways. Here, the present study sought to discover more chemotypes of berberine derivatives as p300 HAT inhibitors and to examine the combination of these novel analogues with doxorubicin for the treatment of breast cancer. A series of novel berberine derivatives with modifications of A/B/D rings of berberine have been designed, synthesized and screened. Compound 7b was found to exhibit inhibitory potency against p300 HAT with IC50 values of 1.51 µM. Western blotting proved that 7b decreased H3K27Ac and interfered with the expression of oncology-relevant protein in MCF-7 cells. Further bioactive evaluation showed that combination of compound 7b with doxorubicin could significantly inhibit tumor growth and invasion in vitro and in vivo.

Effects of the omega-3 fatty acid DHA on histone and p53 acetylation in diffuse large B cell lymphoma.

Diffuse large B cell lymphoma (DLBCL) often develops resistance and/or relapses in response to immunochemotherapy. Epigenetic modifiers are frequently mutated in DLBCL, i.e., the lysine (histone) acetyltransferases CREBBP and EP300. Mutations in CBP/p300 can prevent the proper acetylation and activation of (i) enhancer sequences of genes required for essential functions (e.g., germinal center exit and differentiation) and (ii) the tumor suppressor p53. Based on evidence that omega-3 fatty acids (ω-3 FAs) affect histone acetylation in various cancers, we investigated whether ω-3 FA docosahexaenoic acid (DHA) could modify levels of histone and p53 acetylation in three DLBCL cell lines (at different CREBBP/EP300 mutational status) versus normal B cells. Exposure to DHA at clinically attainable doses was shown to significantly alter the genome-wide levels of histone posttranslational modifications in a cell-line-dependent and dose-dependent manner. Although histone acetylation did not increase uniformly, as initially expected, levels of p53 acetylation increased consistently. Quantitative reverse transcription polymerase chain reaction results revealed significant changes in expression of multiple genes, including increased expression of CREBBP and of PRDM1 (required for differentiation into plasma cells or memory B cells). Taken together, our results provide (to our knowledge) the first characterization of the epigenetic effects of ω-3 FAs in DLBCL.

Pantothenate and L-Carnitine Supplementation Improves Pathological Alterations in Cellular Models of KAT6A Syndrome.

Mutations in several genes involved in the epigenetic regulation of gene expression have been considered risk alterations to different intellectual disability (ID) syndromes associated with features of autism spectrum disorder (ASD). Among them are the pathogenic variants of the lysine-acetyltransferase 6A (KAT6A) gene, which causes KAT6A syndrome. The KAT6A enzyme participates in a wide range of critical cellular functions, such as chromatin remodeling, gene expression, protein synthesis, cell metabolism, and replication. In this manuscript, we examined the pathophysiological alterations in fibroblasts derived from three patients harboring KAT6A mutations. We addressed survival in a stress medium, histone acetylation, protein expression patterns, and transcriptome analysis, as well as cell bioenergetics. In addition, we evaluated the therapeutic effectiveness of epigenetic modulators and mitochondrial boosting agents, such as pantothenate and L-carnitine, in correcting the mutant phenotype. Pantothenate and L-carnitine treatment increased histone acetylation and partially corrected protein and transcriptomic expression patterns in mutant KAT6A cells. Furthermore, the cell bioenergetics of mutant cells was significantly improved. Our results suggest that pantothenate and L-carnitine can significantly improve the mutant phenotype in cellular models of KAT6A syndrome.

Celastrol inhibits lung cancer growth by triggering histone acetylation and acting synergically with HDAC inhibitors.

Alterations in histone modification have been linked to cancer development and progression. Celastrol, a Chinese herbal compound, shows potent anti-tumor effects through multiple signaling pathways. However, the involvement of histone modifications in this process has not yet been illustrated. In this study, barcode sequencing of a eukaryotic genome-wide deletion library revealed that histone modifications, especially histone acetylation associated with the NuA4 histone acetyltransferase complex, were involved in the anti-proliferation actions of celastrol. The essential roles of histone modification were verified by celastrol sensitivity tests in cells lacking specific genes, such as genes encoding the subunits of the NuA4 and Swr1 complex. The combination of celastrol and histone deacetylase inhibitors (HDACi), rather than the combination of celastrol and histone acetyltransferase inhibitors, synergistically suppressed cancer cell proliferation. In addition to upregulating H4K16 acetylation (H4K16ac), celastrol regulates H3K4 tri-methylation and H3S10 phosphorylation. Celastrol treatment significantly enhanced the suppressive effects of HDACi on lung cancer cell allografts in mice, with significant H4K16ac upregulation, indicating that a combination of celastrol and HDACi is a potential novel therapeutic approach for patients with lung cancer.

The Non-Specific Lethal (NSL) Histone Acetyltransferase Complex Transcriptionally Regulates Yin Yang 1-Mediated Cell Proliferation in Human Cells.

The human males absent on the first (MOF)-containing non-specific lethal (NSL) histone acetyltransferase (HAT) complex acetylates histone H4 at lysine K5, K8, and K16. This complex shares several subunits with other epigenetic regulatory enzymes, which highlights the complexity of its intracellular function. However, the effect of the NSL HAT complex on the genome and target genes in human cells is still unclear. By using a CRISPR/Cas9-mediated NSL3-knockout 293T cell line and chromatin immunoprecipitation-sequencing (ChIP-Seq) approaches, we identified more than 100 genes as NSL HAT transcriptional targets, including several transcription factors, such as Yin Yang 1 (YY1) which are mainly involved in cell proliferation, biological adhesion, and metabolic processes. We found here that the ChIP-Seq peaks of MOF and NSL3 co-localized with H4K16ac, H3K4me2, and H3K4me3 at the transcriptional start site of YY1. In addition, both the mRNA and protein expression levels of YY1 were regulated by silencing or overexpressing NSL HAT. Interestingly, the expression levels of cell division cycle 6, a downstream target gene of YY1, were regulated by MOF or NSL3. In addition, the suppressed clonogenic ability of HepG2 cells caused by siNSL3 was reversed by overexpressing YY1, suggesting the involvement of YY1 in NSL HAT functioning. Additionally, de novo motif analysis of MOF and NSL3 targets indicated that the NSL HAT complex may recognize the specific DNA-binding sites in the promoter region of target genes in order to regulate their transcription.

The histone lysine acetyltransferase HBO1 (KAT7) regulates hematopoietic stem cell quiescence and self-renewal.

The histone acetyltransferase HBO1 (MYST2, KAT7) is indispensable for postgastrulation development, histone H3 lysine 14 acetylation (H3K14Ac), and the expression of embryonic patterning genes. In this study, we report the role of HBO1 in regulating hematopoietic stem cell function in adult hematopoiesis. We used 2 complementary cre-recombinase transgenes to conditionally delete Hbo1 (Mx1-Cre and Rosa26-CreERT2). Hbo1-null mice became moribund due to hematopoietic failure with pancytopenia in the blood and bone marrow 2 to 6 weeks after Hbo1 deletion. Hbo1-deleted bone marrow cells failed to repopulate hemoablated recipients in competitive transplantation experiments. Hbo1 deletion caused a rapid loss of hematopoietic progenitors. The numbers of lineage-restricted progenitors for the erythroid, myeloid, B-, and T-cell lineages were reduced. Loss of HBO1 resulted in an abnormally high rate of recruitment of quiescent hematopoietic stem cells (HSCs) into the cell cycle. Cycling HSCs produced progenitors at the expense of self-renewal, which led to the exhaustion of the HSC pool. Mechanistically, genes important for HSC functions were downregulated in HSC-enriched cell populations after Hbo1 deletion, including genes essential for HSC quiescence and self-renewal, such as Mpl, Tek(Tie-2), Gfi1b, Egr1, Tal1(Scl), Gata2, Erg, Pbx1, Meis1, and Hox9, as well as genes important for multipotent progenitor cells and lineage-specific progenitor cells, such as Gata1. HBO1 was required for H3K14Ac through the genome and particularly at gene loci required for HSC quiescence and self-renewal. Our data indicate that HBO1 promotes the expression of a transcription factor network essential for HSC maintenance and self-renewal in adult hematopoiesis.

Sophora subprostrate polysaccharide regulates histone acetylation to inhibit inflammation in PCV2-infected murine splenic lymphocytes in vitro and in vivo.

Porcine circovirus type 2 (PCV2) has caused large economic losses in the swine industry worldwide; therefore, research on relevant therapeutic medicines is still urgently needed. To define the relationship between histone acetylation and inflammation induced by PCV2, we investigated whether traditional Chinese medicinal polysaccharides could alleviate viral infection by regulating histone acetylation. In this study, Sophora subprostrate polysaccharide (SSP)-treated PCV2-infected murine splenic lymphocytes in vitro and murine spleen in vivo were used to explore the regulatory effects of SSP on inflammation and histone acetylation caused by PCV2. SSP at different concentrations significantly reduced the secretion levels of the proinflammatory cytokines TNF-α and IL-6, the activity of COX-2, the mRNA expression levels of TNF-α, IL-6, iNOS and COX-2 and the protein expression levels of iNOS and COX-2 but promoted the secretion and mRNA expression levels of IL-10. Furthermore, the different concentrations of SSP significantly regulated the activity of histone acetylase (HAT) and the mRNA expression of HAT1, increased the activity of histone deacetylase (HDAC) and the mRNA expression of HDAC1 and reduced the protein expression levels of Ac-H3 and Ac-H4. Overall, SSP inhibited inflammation in PCV2-infected murine splenic lymphocytes by regulating histone acetylation in vitro and in vivo, thus playing an important role in PCV2 infection.

Global Microbiota-Dependent Histone Acetylation Patterns Are Irreversible and Independent of Short Chain Fatty Acids.

BACKGROUND AND AIMS: Although germ-free mice are an indispensable tool in studying the gut microbiome and its effects on host physiology, they are phenotypically different than their conventional counterparts. While antibiotic-mediated microbiota depletion in conventional mice leads to physiologic alterations that often mimic the germ-free state, the degree to which the effects of microbial colonization on the host are reversible is unclear. The gut microbiota produce abundant short chain fatty acids (SCFAs), and previous studies have demonstrated a link between microbial-derived SCFAs and global hepatic histone acetylation in germ-free mice. APPROACH AND RESULTS: We demonstrate that global hepatic histone acetylation states measured by mass spectrometry remained largely unchanged despite loss of luminal and portal vein SCFAs after antibiotic-mediated microbiota depletion. In contrast to stable hepatic histone acetylation states, we see robust hepatic transcriptomic alterations after microbiota depletion. Additionally, neither dietary supplementation with supraphysiologic levels of SCFA nor the induction of hepatocyte proliferation in the absence of microbiota-derived SCFAs led to alterations in global hepatic histone acetylation. CONCLUSIONS: These results suggest that microbiota-dependent landscaping of the hepatic epigenome through global histone acetylation is static in nature, while the hepatic transcriptome is responsive to alterations in the gut microbiota.

Acetylation-induced PCK isoenzyme transition promotes metabolic adaption of liver cancer to systemic therapy.

Sorafenib and lenvatinib are approved first-line targeted therapies for advanced liver cancer, but most patients develop acquired resistance. Herein, we found that sorafenib induced extensive acetylation changes towards a more energetic metabolic phenotype. Metabolic adaptation was mediated via acetylation of the Lys-491 (K491) residue of phosphoenolpyruvate carboxykinase isoform 2 (PCK2) (PCK2-K491) and Lys-473 (K473) residue of PCK1 (PCK1-K473) by the lysine acetyltransferase 8 (KAT8), resulting in isoenzyme transition from cytoplasmic PCK1 to mitochondrial PCK2. KAT8-catalyzed PCK2 acetylation at K491 impeded lysosomal degradation to increase the level of PCK2 in resistant cells. PCK2 inhibition in sorafenib-resistant cells significantly reversed drug resistance in vitro and in vivo. High levels of PCK2 predicted a shorter progression-free survival time in patients who received sorafenib treatment. Therefore, acetylation-induced isoenzyme transition from PCK1 to PCK2 contributes to resistance to systemic therapeutic drugs in liver cancer. PCK2 may be an emerging target for delaying tumor recurrence.

Garcinol-A Natural Histone Acetyltransferase Inhibitor and New Anti-Cancer Epigenetic Drug.

Garcinol extracted from Garcinia indica fruit peel and leaves is a polyisoprenylated benzophenone. In traditional medicine it was used for its antioxidant and anti-inflammatory properties. Several studies have shown anti-cancer properties of garcinol in cancer cell lines and experimental animal models. Garcinol action in cancer cells is based on its antioxidant and anti-inflammatory properties, but also on its potency to inhibit histone acetyltransferases (HATs). Recent studies indicate that garcinol may also deregulate expression of miRNAs involved in tumour development and progression. This paper focuses on the latest research concerning garcinol as a HAT inhibitor and miRNA deregulator in the development and progression of various cancers. Garcinol may be considered as a candidate for next generation epigenetic drugs, but further studies are needed to establish the precise toxicity, dosages, routes of administration, and safety for patients.

Inhibition of histone acetyltransferase by naringenin and hesperetin suppresses Txnip expression and protects pancreatic ß cells in diabetic mice.

BACKGROUND: The damage of pancreatic ß cells is a major pathogenesis of the development and progression of type 2 diabetes and there is still no effective therapy to protect pancreatic ß cells clinically. In our previous study, we found that Quzhou Fructus Aurantii (QFA), which is rich in flavanones, had the protective effect of pancreatic ß cells in diabetic mice. However, the underlying mechanism is still unclear. PURPOSE: In the current study, we administered naringenin and hesperetin, two major active components of QFA, to protect pancreatic ß cells and to investigate the underlying molecular mechanism focusing on the epigenetic modifications. METHODS: We used diabetic db/db mouse and INS-1 pancreatic ß cell line as in vivo and in vitro models to investigate the protective effect of naringenin and hesperetin on pancreatic ß cells under high glucose environment and the related mechanism. The phenotypic changes were evaluatedby immunostaining and the measurement of biochemical indexes. The molecular mechanism was explored by biological techniques such as western blotting, qPCR, ChIP-seq and ChIP-qPCR, flow cytometry and lentivirus infection. RESULTS: We found that naringenin and hesperetin had an inhibitory effect on histone acetylation. We showed that naringenin and hesperetin protected pancreatic ß cells in vivo and in vitro, and this effect was independent of their direct antioxidant capacity. The further study found that the inhibition of thioredoxin-interacting protein (Txnip) expression regulated by histone acetylation was critical for the protective role of naringenin and hesperetin. Mechanistically, the histone acetylation inhibition by naringenin and hesperetin was achieved through regulating AMPK-mediated p300 inactivation. CONCLUSION: These findings highlight flavanones and the phytomedicine rich in flavanones as important dietary supplements in protecting pancreatic ß cells in advanced diabetes. In addition, targeting histone acetylation by phytomedicine is a potential strategy to delay the development and progression of diabetes.

Food for Bone: Evidence for a Role for Delta-Tocotrienol in the Physiological Control of Osteoblast Migration.

Bone remodeling and repair require osteogenic cells to reach the sites that need to be rebuilt, indicating that stimulation of osteoblast migration could be a promising osteoanabolic strategy. We showed that purified δ-tocotrienol (δ-TT, 10 µg/mL), isolated from commercial palm oil (Elaeis guineensis) fraction, stimulates the migration of both MC3T3-E1 osteoblast-like cells and primary human bone marrow mesenchymal stem cells (BMSC) as detected by wound healing assay or Boyden chamber assay respectively. The ability of δ-TT to promote MC3T3-E1 cells migration is dependent on Akt phosphorylation detected by Western blotting and involves Wnt/ß-catenin signalling pathway activation. In fact, δ-TT increased ß-catenin transcriptional activity, measured using a Nano luciferase assay and pretreatment with procaine (2 µM), an inhibitor of the Wnt/ß-catenin signalling pathway, reducing the wound healing activity of δ-TT on MC3T3-E1 cells. Moreover, δ-TT treatment increased the expression of ß-catenin specific target genes, such as Osteocalcin and Bone Morphogenetic Protein-2, involved in osteoblast differentiation and migration, and increased alkaline phosphatase and collagen content, osteoblast differentiation markers. The ability of δ-TT to enhance the recruitment of BMSC, and to promote MC3T3-E1 differentiation and migratory behavior, indicates that δ-TT could be considered a promising natural anabolic compound.

Synergistic effects of pazopanib and hyperthermia against uterine leiomyosarcoma growth mediated by downregulation of histone acetyltransferase 1.

Pazopanib-a multitargeted tyrosine kinase inhibitor with prominent antiangiogenic effects-has shown promise in the treatment of soft-tissue sarcomas. Hyperthermia has been also applied as an adjunctive treatment to chemotherapy for these malignancies. Here, we show that pazopanib and hyperthermia act synergistically in inhibiting uterine leiomyosarcoma (LMS) cell growth. Compared with either treatment alone, the combination of pazopanib and hyperthermia exerted the highest antitumor activity in a xenograft model. Mechanistically, we found that combined treatment with pazopanib and hyperthermia inhibited histone acetyltransferase 1 (HAT1) expression in LMS cells. The Clock element on the HAT1 promoter was critical for pazopanib- and hyperthermia-induced HAT1 downregulation. Inhibition of HAT1-either by pazopanib and hyperthermia or through HAT1 silencing-was mediated by suppression of Clock. Accordingly, Clock protein reconstitution rescued both HAT1 levels and HAT1-mediated histone acetylation. Immunohistochemistry revealed a higher expression of HAT1 in uterine LMS than in leiomyomas (p = 0.007), with high HAT1 expression levels being associated with poor clinical outcomes (p = 0.007). We conclude that pazopanib and hyperthermia exert synergistic effects against LMS growth by inhibiting HAT1. Further preclinical studies on HAT1 as a potential drug target in uterine LMS are warranted, especially in combination with hyperthermia. KEY MESSAGES: Pazopanib and hyperthermia inhibit the growth of leiomyosarcoma. Their combined use inhibits HAT1 expression in leiomyosarcoma cells. The promoter Clock element is required for HAT1 downregulation. HAT1 expression is higher in leiomyosarcoma than in leiomyomas. An increased HAT1 expression is associated with poor clinical outcomes.

HDAC inhibitors reverse mania-like behavior and modulate epigenetic regulatory enzymes in an animal model of mania induced by Ouabain.

BACKGROUND: The etiology of bipolar disorder (BD) is multifactorial, involving both environmental and genetic factors. Current pharmacological treatment is associated with several side effects, which are the main reason patients discontinue treatment. Epigenetic alterations have been studied for their role in the pathophysiology of BD, as they bridge the gap between gene and environment. OBJECTIVE: Evaluate the effects of histone deacetylase inhibitors on behavior and epigenetic enzymes activity in a rat model of mania induced by ouabain. METHODS: Adult male rats were subjected to a single intracerebroventricular injection of ouabain (10-3 M) followed by 7 days of valproate (200 mg/kg) or sodium butyrate (600 mg/kg) administration. Locomotor and exploratory activities were evaluated in the open-field test. Histone deacetylase, DNA methyltransferase, and histone acetyltransferase activity were assessed in the frontal cortex, hippocampus, and striatum. RESULTS: Ouabain induced hyperactivity in rats, which was reversed by valproate and sodium butyrate treatment. Ouabain did not alter the activity of any of the enzymes evaluated. However, valproate and sodium butyrate decreased the activity of histone deacetylase and DNA methyltransferase. Moreover, there was a positive correlation between these two enzymes. CONCLUSION: These results suggest that targeting epigenetic mechanisms may play an important role in mania-like behavior management.

Epigenetics in rheumatoid arthritis; fibroblast-like synoviocytes as an emerging paradigm in the pathogenesis of the disease.

Rheumatoid arthritis (RA) is characterized by immune dysfunctions and chronic inflammation that mainly affects diarthrodial joints. Genetics has long been surveyed in searching for the etiopathogenesis of the disease and partially clarified the conundrums within this context. Epigenetic alterations, such as DNA methylation, histone modifications, and noncoding RNAs, which have been considered to be involved in RA pathogenesis, likely explain the nongenetic risk factors. Epigenetic modifications may influence RA through fibroblast-like synoviocytes (FLSs). It has been shown that FLSs play an essential role in the onset and exacerbation of RA, and therefore, they may illustrate some aspects of RA pathogenesis. These cells exhibit a unique DNA methylation profile in the early stage of the disease that changes with disease progression. Histone acetylation profile in RA FLSs is disrupted through the imbalance of histone acetyltransferases and histone deacetylase activity. Furthermore, dysregulation of microRNAs (miRNAs) is immense. Most of these miRNAs have shown an aberrant expression in FLSs that are involved in proliferation and cytokine production. Besides, dysregulation of long noncoding RNAs in FLSs has been revealed and attributed to RA pathogenesis. Further investigations are needed to get a better view of epigenetic alterations and their interactions. We also discuss the role of these epigenetic alterations in RA pathogenesis and their therapeutic potential.

Photoelectrochemical determination of the activity of histone acetyltransferase and inhibitor screening by using MoS2 nanosheets.

The enzyme histone acetyltransferase (HAT) catalyzes the acetylation of a substrate peptide, and acetyl coenzyme A is converted to coenzyme A (CoA). A photoelectrochemical method is described for the determination of the HAT activity by using exfoliated MoS2 nanosheets, phos-tag-biotin, and ß-galactosidase (ß-Gal) based signal amplification. The MoS2 nanosheets are employed as the photoactive material, graphene nanosheets as electron transfer promoter, gold nanoparticles as recognition and capture reagent for CoA, and phos-tag-biotin as the reagent to link CoA and ß-Gal. The enzyme ß-Gal catalyzes the hydrolysis of substrate O-galactosyl-4-aminophenol to generate free 4-aminophenol which is a photoelectrochemical electron donor. The photocurrent increases with the activity of HAT. Under optimal conditions, the response is linear in the 0.3 to 100 nM activity range, and the detection limit is 0.14 nM (at S/N = 3). The assay was applied to HAT inhibitor screening, specifically for the inhibitors C646 and anacardic acid. The IC50 values are 0.28 and 39 µM, respectively. The method is deemed to be a promising tool for epigenetic research and HAT-targeted cancer drug discovery. Graphical abstract Histone acetyltransferase was detected using a sensitive photoelectrochemical method using MoS2 nanosheets as photoactive material.

Garcinol, a multifaceted sword for the treatment of Parkinson's disease.

Garcinol, the principal phytoconstituent of plants belonging to the genus Garcinia, is known for its anti-oxidant as well as anti-inflammatory properties, which can be extended to its possible neuroprotective role. Recent reports disseminate the capacity of garcinol to influence neuronal growth and survival, alter the neurochemical status in brain, as well as regulate memory and cognition. The concomitant neuro-rescue property of garcinol may render it as an effective compound in Parkinson's disease (PD) therapeutics since it is capable of ameliorating the related pathophysiological changes. Emerging pieces of evidence linking histone acetylation defects to the progression of neurodegenerative diseases provide an effective basis for targeting PD. Hyperacetylation of histones has been reported in Parkinsonian brain, which demands the use of pharmacological inhibitors of histone acetyltransferases (HAT). Garcinol serves as a potent natural HAT inhibitor and has unveiled promising results in molecular interaction studies against Monoamine oxidase B (MAO-B) and Catechol-O-Methyltransferase (COMT), as well as in L-DOPA induced dyskinesia. This review highlights the prospective implications of garcinol as a novel anti-Parkinsonian agent, and establishes a bridge between histone acetylation defects and the pathological aspects of PD.

Calebin-A induced death of malignant peripheral nerve sheath tumor cells by activation of histone acetyltransferase.

BACKGROUND: Neurofibromatosis type 1 (NF1) is one of the most common hereditary neurocutaneous disorders. The malignant peripheral nerve sheath tumor (MPNST), transformed from NF1 related plexiform neurofibroma, is a rapidly growing and highly invasive tumor. No effective chemotherapeutic agent is currently available. Calebin-A is a derivative from turmeric Curcuma longa. Given the anti-inflammatory and anticancer potentials of curcumin, whether Calebin-A also had the tumoricidal effect upon MPNST cells is still elusive. PURPOSE: To determine whether Calebin-A has the potential for anti-MPNST effect. METHODS: The MTT and FACS analysis of normal Schwann (HSC) and MPNST cells have been employed to determine the tumoricidal effect of Calebin-A. The expression of the signal pathway molecules was assessed by Western blotting. The CHIP with quantitative PCR assay was performed to quantify the promoter DNA binding to acetylated histone 3 (acetyl H3). The enzyme activities of histone acetyltransferase (HAT) and deacetylase (HDAC) have been evaluated by commercial kits. The measurements of tumor size of the xenograft mouse model were also performed. RESULTS: Calebin-A inhibited the proliferation of MPNST and primary neurofibroma cells in a dose-dependent manner. The flow cytometry analysis of the MPNST cells after treatment of 25 µm of Calebin-A demonstrated an increase of population in the G0/G1 phase but decrease in G2/M phase. Before treatment, the expression of Axl, Tyro3, and acetyl H3 was significantly higher in MPNST cells when compared to HSC. The expression of phosphorylated-AKT, -ERK1/2, survivin, hTERT, and acetyl H3 proteins were reduced after treatment. The CHIP assay shows the promoter DNA copies of survivin (BRIC5) and hTERT genes are significantly reduced post-treatment. The enzyme activity of HAT was significantly reduced, but not that of HDAC. Two HAT inhibitors, epigallocatechin-3-gallate (EGCG) and anacardic acid (AA) have also demonstrated a significant inhibitory effect on MPNST cells. Finally, the measurements of tumor size showed a significant reduction of the xenograft tumors after treatment of Calebin-A. CONCLUSION: Both in vitro and in vivo studies showed Calebin-A could inhibit the proliferation of MPNST with suppression of survivin and hTERT. The reduced expression of these two factors might be through the epigenetic histone modification resulting from the decreased activity of HAT.

The epithelial zinc transporter ZIP10 epigenetically regulates human epidermal homeostasis by modulating histone acetyltransferase activity.

BACKGROUND: The skin is the first organ that manifests changes in response to zinc deficiency. However, the molecular mechanism underlying how zinc is involved in skin homeostasis, especially its epigenetic regulation, is largely unknown. OBJECTIVES: In this study we demonstrate the importance of zinc levels and the zinc transporter ZIP10 in the epigenetic maintenance of human epidermal homeostasis. METHODS: Adult human skin, including skin appendages, were stained with anti-ZIP10 antibody. Histone acetyltransferase (HAT) activity was assessed after treating human keratinocytes with ZIP10 small interfering (si)RNAs or the zinc chelator TPEN. ZIP10- or HAT-regulated genes were analysed based on limma bioinformatics analysis for keratinocytes treated with ZIP10 siRNAs or a HAT inhibitor, or using a public database for transcription factors. A reconstituted human skin model was used to validate the role of ZIP10 in epidermal differentiation and the functional association between ZIP10 and HAT. RESULTS: ZIP10 is predominantly expressed in the interfollicular epidermis, epidermal appendages and hair follicles. ZIP10 depletion resulted in epidermal malformations in a reconstituted human skin model via downregulation of the activity of the epigenetic enzyme HAT. This decreased HAT activity, resulting from either ZIP10 depletion or treatment with the zinc chelator TPEN, was readily restored by zinc supplementation. Through bioinformatics analysis for gene sets regulated by knockdown of SLC39A10 (encoding ZIP10) and HAT inhibition, we demonstrated that ZIP10 and HATs were closely linked with the regulation of genes related to epidermal homeostasis, particularly filaggrin and metallothionein. CONCLUSIONS: Our study suggests that ZIP10-mediated zinc distribution is crucial for epidermal homeostasis via HATs. Therefore, zinc-dependent epigenetic regulation could provide alternatives to maintaining healthy skin or alleviating disorders with skin barrier defects.

Histone acetylation increases in response to ferulic, gallic, and sinapic acids acting synergistically in vitro to inhibit Candida albicans yeast-to-hyphae transition.

Novel treatments are needed to prevent candidiasis/candidemia infection due to the emergence of Candida species resistant to current antifungals. Considering the yeast-to-hyphae switch is a critical factor to Candida albicans virulence, phenols common in plant sources have been reported to demonstrating their ability to prevent dimorphism. Therefore, phenols present in many agricultural waste stress (ferulic (FA) and gallic (GA) acid) were initially screened in isolation for their yeast-to-hyphae inhibitory properties at times 3, 6, and 24 hr. Both FA and GA inhibited 50% of hyphae formation inhibitory concentration (IC50 ) but at a concentration of 8.0 ± 0.09 and 90.6 ± 1.05 mM, respectively, at 24 hr. However, the inhibitory effect of FA increased by 1.9-2.6 fold when combined with different GA concentrations. GA and FA values decreased even lower when sinapic acid (SA) was added as a third component. As evidenced by concave isobolograms and combination indexes less than 1, both GA:F A and GA:FA:SA combinations acted synergistically to inhibit 50% hyphae formation at 24 hr. Lastly, acetylation of histone H3 lysine 56 acetylation (H3K56) was higher in response to the triple phenolic cocktail (using the IC50 24 hr inhibitory concentration level) comparable with the nontreated samples, indicating that the phenols inhibited hyphal growth in part by targeting H3K56 acetylation.