HDAC4

Gene Summary

Gene:HDAC4; histone deacetylase 4
Aliases: HD4, AHO3, BDMR, HDACA, HA6116, HDAC-4, HDAC-A
Location:2q37.3
Summary:Histones play a critical role in transcriptional regulation, cell cycle progression, and developmental events. Histone acetylation/deacetylation alters chromosome structure and affects transcription factor access to DNA. The protein encoded by this gene belongs to class II of the histone deacetylase/acuc/apha family. It possesses histone deacetylase activity and represses transcription when tethered to a promoter. This protein does not bind DNA directly, but through transcription factors MEF2C and MEF2D. It seems to interact in a multiprotein complex with RbAp48 and HDAC3. [provided by RefSeq, Jul 2008]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:histone deacetylase 4
HPRD
Source:NCBIAccessed: 25 June, 2015

Ontology:

What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 25 June 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 25 June, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (7)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: HDAC4 (cancer-related)

Guo Y, Shu L, Zhang C, et al.
Curcumin inhibits anchorage-independent growth of HT29 human colon cancer cells by targeting epigenetic restoration of the tumor suppressor gene DLEC1.
Biochem Pharmacol. 2015; 94(2):69-78 [PubMed] Related Publications
Colorectal cancer remains the most prevalent malignancy in humans. The impact of epigenetic alterations on the development of this complex disease is now being recognized. The dynamic and reversible nature of epigenetic modifications makes them a promising target in colorectal cancer chemoprevention and treatment. Curcumin (CUR), the major component in Curcuma longa, has been shown as a potent chemopreventive phytochemical that modulates various signaling pathways. Deleted in lung and esophageal cancer 1 (DLEC1) is a tumor suppressor gene with reduced transcriptional activity and promoter hypermethylation in various cancers, including colorectal cancer. In the present study, we aimed to investigate the inhibitory role of DLEC1 in anchorage-independent growth of the human colorectal adenocarcinoma HT29 cells and epigenetic regulation by CUR. Specifically, we found that CUR treatment inhibited colony formation of HT29 cells, whereas stable knockdown of DLEC1 using lentiviral short hairpin RNA vector increased cell proliferation and colony formation. Knockdown of DLEC1 in HT29 cells attenuated the ability of CUR to inhibit anchorage-independent growth. Methylation-specific polymerase chain reaction (MSP), bisulfite genomic sequencing, and methylated DNA immunoprecipitation revealed that CUR decreased CpG methylation of the DLEC1 promoter in HT29 cells after 5 days of treatment, corresponding to increased mRNA expression of DLEC1. Furthermore, CUR decreased the protein expression of DNA methyltransferases and subtypes of histone deacetylases (HDAC4, 5, 6, and 8). Taken together, our results suggest that the inhibitory effect of CUR on anchorage-independent growth of HT29 cells could, at least in part, involve the epigenetic demethylation and up-regulation of DLEC1.

Laitinen VH, Rantapero T, Fischer D, et al.
Fine-mapping the 2q37 and 17q11.2-q22 loci for novel genes and sequence variants associated with a genetic predisposition to prostate cancer.
Int J Cancer. 2015; 136(10):2316-27 [PubMed] Article available free on PMC after 15/05/2016 Related Publications
The 2q37 and 17q12-q22 loci are linked to an increased prostate cancer (PrCa) risk. No candidate gene has been localized at 2q37 and the HOXB13 variant G84E only partially explains the linkage to 17q21-q22 observed in Finland. We screened these regions by targeted DNA sequencing to search for cancer-associated variants. Altogether, four novel susceptibility alleles were identified. Two ZNF652 (17q21.3) variants, rs116890317 and rs79670217, increased the risk of both sporadic and hereditary PrCa (rs116890317: OR = 3.3-7.8, p = 0.003-3.3 × 10(-5) ; rs79670217: OR = 1.6-1.9, p = 0.002-0.009). The HDAC4 (2q37.2) variant rs73000144 (OR = 14.6, p = 0.018) and the EFCAB13 (17q21.3) variant rs118004742 (OR = 1.8, p = 0.048) were overrepresented in patients with familial PrCa. To map the variants within 2q37 and 17q11.2-q22 that may regulate PrCa-associated genes, we combined DNA sequencing results with transcriptome data obtained by RNA sequencing. This expression quantitative trait locus (eQTL) analysis identified 272 single-nucleotide polymorphisms (SNPs) possibly regulating six genes that were differentially expressed between cases and controls. In a modified approach, prefiltered PrCa-associated SNPs were exploited and interestingly, a novel eQTL targeting ZNF652 was identified. The novel variants identified in this study could be utilized for PrCa risk assessment, and they further validate the suggested role of ZNF652 as a PrCa candidate gene. The regulatory regions discovered by eQTL mapping increase our understanding of the relationship between regulation of gene expression and susceptibility to PrCa and provide a valuable starting point for future functional research.

Shi Q, Li J, Feng Z, et al.
Effect of ginsenoside Rh2 on the migratory ability of HepG2 liver carcinoma cells: recruiting histone deacetylase and inhibiting activator protein 1 transcription factors.
Mol Med Rep. 2014; 10(4):1779-85 [PubMed] Article available free on PMC after 15/05/2016 Related Publications
In previous experiments, ginsenoside Rh2 induced apoptosis and cell cycle arrest, which indicates a potential role for ginsenoside Rh2 in anticancer treatment. The effect of ginsenoside Rh2 on cancer is marked and ginsenoside Rh2 has been shown to inhibit pancreatic tumor migratory ability. In the present study, Transwell chambers were used in order to investigate whether ginsenoside Rh2 inhibits the migratory ability of HepG2 liver carcinoma cells. Furthermore, to analyze activator protein 1 (AP-1) transcription factor expression following Rh2 treatment, ten plasmids encoding Renilla luciferase coupled to the transcription factors were transiently transfected into the HepG2 cells and luciferase was detected by the Luciferase Reporter Assay system reagent. The results indicated that ginsenoside Rh2 inhibited HepG2 cell migratory ability. The expression levels of AP-1 transcription factors were increased in HepG2 cells following induction by phorbol 12-myristate 13-acetate, but ginsenoside Rh2 suppressed this induced AP‑1 expression. AP-1 transcription factors recruit histone deacetylase (HDAC)4 and affect its transcription, thus, the expression levels of HDAC4 were also analyzed, and these were found to be increased in the Rh2 treatment group. Matrix metalloproteinase 3 (MMP3), a gene downstream of AP-1, was then investigated, and the treatment group expressed reduced levels of MMP3 gene and protein. Therefore, the inhibitory effect of ginsenoside Rh2 on the migratory ability of HepG2 may be presumed to occur by the recruitment of HDAC and the resulting inhibition of AP‑1 transcription factors, in order to reduce the expression levels of MMP3 gene and protein.

Shan C, Elf S, Ji Q, et al.
Lysine acetylation activates 6-phosphogluconate dehydrogenase to promote tumor growth.
Mol Cell. 2014; 55(4):552-65 [PubMed] Article available free on PMC after 21/08/2015 Related Publications
Although the oxidative pentose phosphate pathway is important for tumor growth, how 6-phosphogluconate dehydrogenase (6PGD) in this pathway is upregulated in human cancers is unknown. We found that 6PGD is commonly activated in EGF-stimulated cells and human cancer cells by lysine acetylation. Acetylation at K76 and K294 of 6PGD promotes NADP(+) binding to 6PGD and formation of active 6PGD dimers, respectively. Moreover, we identified DLAT and ACAT2 as upstream acetyltransferases of K76 and K294, respectively, and HDAC4 as the deacetylase of both sites. Expressing acetyl-deficient mutants of 6PGD in cancer cells significantly attenuated cell proliferation and tumor growth. This is due in part to reduced levels of 6PGD products ribulose-5-phosphate and NADPH, which led to reduced RNA and lipid biosynthesis as well as elevated ROS. Furthermore, 6PGD activity is upregulated with increased lysine acetylation in primary leukemia cells from human patients, providing mechanistic insights into 6PGD upregulation in cancer cells.

Yu H, Lu Y, Li Z, Wang Q
microRNA-133: expression, function and therapeutic potential in muscle diseases and cancer.
Curr Drug Targets. 2014; 15(9):817-28 [PubMed] Related Publications
microRNAs (miRNAs) are a class of small non-coding RNAs that are 18-25 nucleotides (nt) in length and negatively regulate gene expression post-transcriptionally. miRNAs are known to mediate myriad processes and pathways. While many miRNAs are expressed ubiquitously, some are expressed in a tissue specific manner. miR-133 is one of the most studied and best characterized miRNAs to date. Specifically expressed in muscles, it has been classified as myomiRNAs and is necessary for proper skeletal and cardiac muscle development and function. Genes encoding miR-133 (miR-133a-1, miR-133a-2 and miR-133b) are transcribed as bicistronic transcripts together with miR-1-2, miR-1-1, and miR-206, respectively. However, they exhibit opposing impacts on muscle development. miR-133 gets involved in muscle development by targeting a lot of genes, including SFR, HDAC4, cyclin D2 and so on. Its aberrant expression has been linked to many diseases in skeletal muscle and cardiac muscle such as cardiac hypertrophy, muscular dystrophy, heart failure, cardiac arrhythmia. Beyond the study in muscle, miR-133 has been implicated in cancer and identified as a key factor in cancer development, including bladder cancer, prostate cancer and so on. Much more attention has been drawn to the versatile molecular functions of miR-133, making it a truly valuable therapeutic gene in miRNA-based gene therapy. In this review, we identified and summarized the results of studies of miR-133 with emphasis on its function in human diseases in muscle and cancer, and highlighted its therapeutic value. It might provide researchers a new insight into the biological significance of miR-133.

Moreau P, Cavo M, Sonneveld P, et al.
Combination of international scoring system 3, high lactate dehydrogenase, and t(4;14) and/or del(17p) identifies patients with multiple myeloma (MM) treated with front-line autologous stem-cell transplantation at high risk of early MM progression-related death.
J Clin Oncol. 2014; 32(20):2173-80 [PubMed] Related Publications
PURPOSE: To construct and validate among patients with multiple myeloma (MM) who were treated with intensive therapy a prognostic index of early MM progression-related death.
PATIENTS AND METHODS: Patient-level data from the Intergroupe Francophone du Myélome (IFM) 2005-01 trial (N = 482) were used to construct the prognostic index. The event was MM progression-related death within 2 years from treatment initiation. The index was validated using data from three other trials: the Gruppo Italiano Malattie Ematologiche dell' Adulto (GIMEMA) 26866138-MMY-3006 trial (N = 480), the Programa para el Estudio de la Terapéutica en Hemopatía Maligna (PETHEMA)-GEMMENOS65 trial (N = 390), and the Hemato-Oncologie voor Volwassenen Nederland (HOVON) -65/German-Speaking Myeloma Multicenter Group (GMMG) -HD4 trial (N = 827).
RESULTS: The risk of early MM progression-related death was related to three independent prognostic variables: lactate dehydrogenase (LDH) higher than than normal, International Staging System 3 (ISS3), and adverse cytogenetics [t(4;14) and/or del(17p)]. These three variables enabled the definition of an ordinal prognostic classification composed of four scores (0 to 3). Patients with a score of 3, defined by the presence of t(4;14) and/or del(17p) in addition to ISS3 and/or high LDH, comprised 5% (20 of 387 patients) to 8% (94 of 1,139 patients) of the patients in the learning and validation samples, respectively, and they had a very poor prognosis. When applied to the population of 855 patients who had received bortezomib-based induction therapy in the four trials, the prognostic classification was also able to segregate patients into four categories, with a very poor prognosis attributed to patients with a score of 3.
CONCLUSION: Our model allows the simple definition of a subgroup of MM patients at high risk of early MM progression-related death despite the use of the most modern and effective strategies.

Chen DQ, Pan BZ, Huang JY, et al.
HDAC 1/4-mediated silencing of microRNA-200b promotes chemoresistance in human lung adenocarcinoma cells.
Oncotarget. 2014; 5(10):3333-49 [PubMed] Article available free on PMC after 21/08/2015 Related Publications
Chemoresistance is one of the most significant obstacles in lung adenocarcinoma (LAD) treatment, and this process involves genetic and epigenetic dysregulation of chemoresistance-related genes. Previously, we have shown that restoration of microRNA (miR)-200b significantly reverses chemoresistance of human LAD cells by targeting E2F3. However, the molecular mechanisms involved in the silencing of miR-200b are still unclear. Here we showed that histone deacetylase (HDAC) inhibitors could restore the expression of miR-200b and reverse chemoresistant phenotypes of docetaxel-resistant LAD cells. HDAC1/4 repression significantly increased miR-200b expression by upregulating histone-H3 acetylation level at the two miR-200b promoters partially via a Sp1-dependent pathway. Furthermore, silencing of HDAC1/4 suppressed cell proliferation, promoted cell apoptosis, induced G2/M cell cycle arrest and ultimately reversed in vitro and in vivo chemoresistance of docetaxel-resistant LAD cells, at least partially in a miR-200b-dependent manner. HDAC1/4 suppression-induced rescue of miR-200b contributed to downregulation of E2F3, survivin and Aurora-A, and upregulation of cleaved-caspase-3. HDAC1/4 levels in docetaxel-insensitive human LAD tissues, inversely correlated with miR-200b, were upregulated compared with docetaxel-sensitive tissues. Taken together, our findings suggest that the HDAC1/4/Sp1/miR-200b/E2F3 pathway is responsible for chemoresistance of docetaxel-resistant LAD cells.

Sakai Y, Souzaki R, Yamamoto H, et al.
Testicular sex cord-stromal tumor in a boy with 2q37 deletion syndrome.
BMC Med Genomics. 2014; 7:19 [PubMed] Article available free on PMC after 21/08/2015 Related Publications
BACKGROUND: 2q37 deletion syndrome is a rare congenital disorder that is characterized by facial dysmorphism, obesity, vascular and skeletal malformations, and a variable degree of intellectual disability. To date, common but variable phenotypes, such as skeletal or digit malformations and obesity, have been associated with the deleted size or affected genes at chromosome 2q37. However, it remains elusive whether 2q37 deletion per se or other genetic factors, such as copy number variations (CNVs), may confer the risk for the tumorigenic condition.
CASE PRESENTATION: We report a two-year-old Japanese boy with 2q37 deletion syndrome who exhibited the typical facial appearance, coarctation of the aorta, and a global developmental delay, while lacking the symptoms of brachydactyly and obesity. He developed a sex cord-stromal tumor of the right testis at three months of age. The array comparative genome hybridization analysis identified an 8.2-Mb deletion at 2q37.1 (chr2:234,275,216-242,674,807) and it further revealed two additional CNVs: duplications at 1p36.33-p36.32 (chr1:834,101-2,567,832) and 20p12.3 (chr20:5,425,762-5,593,096). The quantitative PCRs confirmed the heterozygous deletion of HDAC4 at 2q37.3 and duplications of DVL1 at 1q36 and GPCPD1 at 20p12.3.
CONCLUSION: This study describes the unique phenotypes in a boy with 2q37 deletion and additional CNVs at 1p36.33-p36.32 and 20p12.3. The data provide evidence that the phenotypic variations and unusual complications of 2q37 deletion syndrome are not simply explained by the deleted size or genes located at 2q37, but that external CNVs may account at least in part for their variant phenotypes. Accumulating the CNV data for chromosomal disorders will be beneficial for understanding the genetic effects of concurrent CNVs on the syndromic phenotypes and rare complications.

Garee JP, Chien CD, Li JV, et al.
Regulation of HER2 oncogene transcription by a multifunctional coactivator/corepressor complex.
Mol Endocrinol. 2014; 28(6):846-59 [PubMed] Article available free on PMC after 21/08/2015 Related Publications
Transcription of the HER2 oncogene can be repressed by estrogen (E2). We now show that, a splice isoform of the nuclear receptor coactivator AIB1, AIB1-Δ4, is able to reverse E2 repression of HER2 gene expression in breast cancer cells. The first 224 amino acids of AIB1 that are absent in AIB1-Δ4, bind a co-repressor, ANCO1. Using chromatin immunoprecipitation assay approaches in MCF7 and BT474 cell lines, we demonstrate that AIB1 and AIB1-Δ4 can bind to the E2 regulatory site in the first intron of the HER2 gene, after E2 treatment, but only full-length AIB1 recruits ANCO1. Consistent with E2-induced chromatin repression, the AIB1-ANCO1 complex recruits HDAC3 and HDAC4 to the intronic estrogen response element and the proximal promoter acquires the repressive chromatin mark H3K9me3 and loses H3K4me1. In contrast, AIB1-Δ4 does not recruit ANCO 1, HDAC3, or HDAC4 and the proximal promoter retains activation marks of H3K4me1. In cell lines with low levels of ANCO1 (T47D), E2 does not repress HER2 gene transcription but the repressive response can be restored by overexpression of ANCO1. ANCO1 can also repress other E2-responsive genes, indicating that AIB1, AIB1-Δ4 and ANCO1 are important determinants of endocrine and growth factor responsiveness in breast cancer.

Wang Z, Qin G, Zhao TC
HDAC4: mechanism of regulation and biological functions.
Epigenomics. 2014; 6(1):139-50 [PubMed] Article available free on PMC after 21/08/2015 Related Publications
The acetylation and deacetylation of histones plays an important role in the regulation of gene transcriptions. Histone acetylation is mediated by histone acetyltransferase; the resulting modification in the structure of chromatin leads to nucleosomal relaxation and altered transcriptional activation. The reverse reaction is mediated by histone deacetylase (HDAC), which induces deacetylation, chromatin condensation and transcriptional repression. HDACs are divided into three distinct classes: I, II, and III, on the basis of size and sequence homology, as well as formation of distinct complexes. Among class II HDACs, HDAC4 is implicated in controlling gene expression important for diverse cellular functions. Basic and clinical experimental evidence has established that HDAC4 performs a wide variety of functions. Understanding the biological significance of HDAC4 will not only provide new insight into the mechanisms of HDAC4 involved in mediating biological response, but also form a platform to develop a therapeutic strategy to achieve clinical implications.

Bøgsted M, Bilgrau AE, Wardell CP, et al.
Proof of the concept to use a malignant B cell line drug screen strategy for identification and weight of melphalan resistance genes in multiple myeloma.
PLoS One. 2013; 8(12):e83252 [PubMed] Article available free on PMC after 21/08/2015 Related Publications
In a conceptual study of drug resistance we have used a preclinical model of malignant B-cell lines by combining drug induced growth inhibition and gene expression profiling. In the current report a melphalan resistance profile of 19 genes were weighted by microarray data from the MRC Myeloma IX trial and time to progression following high dose melphalan, to generate an individual melphalan resistance index. The resistance index was subsequently validated in the HOVON65/GMMG-HD4 trial data set to prove the concept. Biologically, the assigned resistance indices were differentially distributed among translocations and cyclin D expression classes. Clinically, the 25% most melphalan resistant, the intermediate 50% and the 25% most sensitive patients had a median progression free survival of 18, 32 and 28 months, respectively (log-rank P-value  = 0.05). Furthermore, the median overall survival was 45 months for the resistant group and not reached for the intermediate and sensitive groups (log-rank P-value  = 0.003) following 38 months median observation. In a multivariate analysis, correcting for age, sex and ISS-staging, we found a high resistance index to be an independent variable associated with inferior progression free survival and overall survival. This study provides clinical proof of concept to use in vitro drug screen for identification of melphalan resistance gene signatures for future functional analysis.

Bao ZS, Li MY, Wang JY, et al.
Prognostic value of a nine-gene signature in glioma patients based on mRNA expression profiling.
CNS Neurosci Ther. 2014; 20(2):112-8 [PubMed] Related Publications
INTRODUCTION: Gliomas are the most common primary brain tumors in adults and a significant cause of cancer-related mortality. A 9-gene signature was identified as a novel prognostic model reflecting survival situation obviously in gliomas.
AIMS: To identify an mRNA expression signature to improve outcome prediction for patients with different glioma grades.
RESULTS: We used whole-genome mRNA expression microarray data of 220 glioma samples of all grades from the Chinese Glioma Genome Atlas (CGGA) database (http://www.cgga.org.cn) as a discovery set and data from Rembrandt and GSE16011 for validation sets. Data from every single grade were analyzed by the Kaplan-Meier method with a two-sided log-rank test. Univariate Cox regression and linear risk score formula were applied to derive a gene signature with better prognostic performance. We found that patients who had high risk score according to the signature had poor overall survival compared with patients who had low risk score. Highly expressed genes in the high-risk group were analyzed by gene ontology (GO) and gene set variation analysis (GSVA). As a result, the reason for the divisibility of gliomas was likely due to cell life processes and adhesion.
CONCLUSION: This 9-gene-signature prediction model provided a more accurate predictor of prognosis that denoted patients with high risk score have poor outcome. Moreover, these risk models based on defined molecular profiles showed the considerable prospect in personalized cancer management.

Lee YS, Lee JW, Jang JW, et al.
Runx3 inactivation is a crucial early event in the development of lung adenocarcinoma.
Cancer Cell. 2013; 24(5):603-16 [PubMed] Related Publications
Targeted inactivation of Runx3 in mouse lung induced mucinous and nonmucinous adenomas and markedly shortened latency of adenocarcinoma formation induced by oncogenic K-Ras. RUNX3 was frequently inactivated in K-RAS mutated human lung adenocarcinomas. A functional genetic screen of a fly mutant library and molecular analysis in cultured cell lines revealed that Runx3 forms a complex with BRD2 in a K-Ras-dependent manner in the early phase of the cell cycle; this complex induces expression of p14(ARF)/p19(Arf) and p21(WAF/CIP). When K-Ras was constitutively activated, the Runx3-BRD2 complex was stably maintained and expression of both p14(ARF) and p21(WAF/CIP) was prolonged. These results provide a missing link between oncogenic K-Ras and the p14(ARF)-p53 pathway, and may explain how cells defend against oncogenic K-Ras.

Luis-Ravelo D, Antón I, Zandueta C, et al.
A gene signature of bone metastatic colonization sensitizes for tumor-induced osteolysis and predicts survival in lung cancer.
Oncogene. 2014; 33(43):5090-9 [PubMed] Related Publications
Bone metastasis of lung adenocarcinoma (AC) is a frequent complication of advanced disease. The purpose of this study was to identify key mediators conferring robust prometastatic activity with clinical significance. We isolated highly metastatic subpopulations (HMS) using a previously described in vivo model of lung AC bone metastasis. We performed transcriptomic profiling of HMS and stringent bioinformatics filtering. Functional validation was assessed by overexpression and lentiviral silencing of single, double and triple combination in vivo and in vitro. We identified HDAC4, PITX1 and ROBO1 that decreased bone metastatic ability after their simultaneous abrogation. These effects were solely linked to defects in osseous colonization. The molecular mechanisms related to bone colonization were mediated by non-cell autonomous effects that include the following: (1) a marked decrease in osteoclastogenic activity in vitro and in vivo, an effect associated with reduced pro-osteoclastogenic cytokines IL-11 and PTHrP expression levels, as well as decreased in vitro expression of stromal rankl in conditions mimicking tumor-stromal interactions; (2) an abrogated response to TGF-β signaling by decreased phosphorylation and levels of Smad2/3 in tumor cells and (3) an impaired metalloproteolytic activity in vitro. Interestingly, coexpression of HDAC4 and PITX1 conferred high prometastatic activity in vivo. Further, levels of both genes correlated with patients at higher risk of metastasis in a clinical lung AC data set and with a poorer clinical outcome. These findings provide functional and clinical evidence that this metastatic subset is an important determinant of osseous colonization. These data suggest novel therapeutic targets to effectively block lung AC bone metastasis.

Pavlik CM, Wong CY, Ononye S, et al.
Santacruzamate A, a potent and selective histone deacetylase inhibitor from the Panamanian marine cyanobacterium cf. Symploca sp.
J Nat Prod. 2013; 76(11):2026-33 [PubMed] Article available free on PMC after 21/08/2015 Related Publications
A dark brown tuft-forming cyanobacterium, morphologically resembling the genus Symploca, was collected during an expedition to the Coiba National Park, a UNESCO World Heritage Site on the Pacific coast of Panama. Phylogenetic analysis of its 16S rRNA gene sequence indicated that it is 4.5% divergent from the type strain for Symploca and thus is likely a new genus. Fractionation of the crude extract led to the isolation of a new cytotoxin, designated santacruzamate A (1), which has several structural features in common with suberoylanilide hydroxamic acid [(2), SAHA, trade name Vorinostat], a clinically approved histone deacetylase (HDAC) inhibitor used to treat refractory cutaneous T-cell lymphoma. Recognition of the structural similarly of 1 and SAHA led to the characterization of santacruzamate A as a picomolar level selective inhibitor of HDAC2, a Class I HDAC, with relatively little inhibition of HDAC4 or HDAC6, both Class II HDACs. As a result, chemical syntheses of santacruzamate A as well as a structurally intriguing hybrid molecule, which blends aspects of both agents (1 and 2), were achieved and evaluated for their HDAC activity and specificity.

Cohen AL, Piccolo SR, Cheng L, et al.
Genomic pathway analysis reveals that EZH2 and HDAC4 represent mutually exclusive epigenetic pathways across human cancers.
BMC Med Genomics. 2013; 6:35 [PubMed] Article available free on PMC after 21/08/2015 Related Publications
BACKGROUND: Alterations in epigenetic marks, including methylation or acetylation, are common in human cancers. For many epigenetic pathways, however, direct measures of activity are unknown, making their role in various cancers difficult to assess. Gene expression signatures facilitate the examination of patterns of epigenetic pathway activation across and within human cancer types allowing better understanding of the relationships between these pathways.
METHODS: We used Bayesian regression to generate gene expression signatures from normal epithelial cells before and after epigenetic pathway activation. Signatures were applied to datasets from TCGA, GEO, CaArray, ArrayExpress, and the cancer cell line encyclopedia. For TCGA data, signature results were correlated with copy number variation and DNA methylation changes. GSEA was used to identify biologic pathways related to the signatures.
RESULTS: We developed and validated signatures reflecting downstream effects of enhancer of zeste homolog 2(EZH2), histone deacetylase(HDAC) 1, HDAC4, sirtuin 1(SIRT1), and DNA methyltransferase 2(DNMT2). By applying these signatures to data from cancer cell lines and tumors in large public repositories, we identify those cancers that have the highest and lowest activation of each of these pathways. Highest EZH2 activation is seen in neuroblastoma, hepatocellular carcinoma, small cell lung cancer, and melanoma, while highest HDAC activity is seen in pharyngeal cancer, kidney cancer, and pancreatic cancer. Across all datasets studied, activation of both EZH2 and HDAC4 is significantly underrepresented. Using breast cancer and glioblastoma as examples to examine intrinsic subtypes of particular cancers, EZH2 activation was highest in luminal breast cancers and proneural glioblastomas, while HDAC4 activation was highest in basal breast cancer and mesenchymal glioblastoma. EZH2 and HDAC4 activation are associated with particular chromosome abnormalities: EZH2 activation with aberrations in genes from the TGF and phosphatidylinositol pathways and HDAC4 activation with aberrations in inflammatory and chemokine related genes.
CONCLUSION: Gene expression patterns can reveal the activation level of epigenetic pathways. Epigenetic pathways define biologically relevant subsets of human cancers. EZH2 activation and HDAC4 activation correlate with growth factor signaling and inflammation, respectively, and represent two distinct states for cancer cells. This understanding may allow us to identify targetable drivers in these cancer subsets.

Di Giorgio E, Clocchiatti A, Piccinin S, et al.
MEF2 is a converging hub for histone deacetylase 4 and phosphatidylinositol 3-kinase/Akt-induced transformation.
Mol Cell Biol. 2013; 33(22):4473-91 [PubMed] Article available free on PMC after 21/08/2015 Related Publications
The MEF2-class IIa histone deacetylase (HDAC) axis operates in several differentiation pathways and in numerous adaptive responses. We show here that nuclear active HDAC4 and HDAC7 display transforming capability. HDAC4 oncogenic potential depends on the repression of a limited set of genes, most of which are MEF2 targets. Genes verified as targets of the MEF2-HDAC axis are also under the influence of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway that affects MEF2 protein stability. A signature of MEF2 target genes identified by this study is recurrently repressed in soft tissue sarcomas. Correlation studies depicted two distinct groups of soft tissue sarcomas: one in which MEF2 repression correlates with PTEN downregulation and a second group in which MEF2 repression correlates with HDAC4 levels. Finally, simultaneous pharmacological inhibition of the PI3K/Akt pathway and of MEF2-HDAC interaction shows additive effects on the transcription of MEF2 target genes and on sarcoma cells proliferation. Overall, our work pinpoints an important role of the MEF2-HDAC class IIa axis in tumorigenesis.

Gruhn B, Naumann T, Gruner D, et al.
The expression of histone deacetylase 4 is associated with prednisone poor-response in childhood acute lymphoblastic leukemia.
Leuk Res. 2013; 37(10):1200-7 [PubMed] Related Publications
This study aimed at the identification of histone deacetylase (HDAC) isoforms relevant for childhood acute lymphoblastic leukemia (ALL). Expression of HDAC1-11 was determined in 93 primary ALL and eight healthy donor samples. HDAC1, HDAC2 and HDAC8 showed significantly higher expressions in ALL samples. Correlation analysis of HDAC expression with clinicopathological parameters revealed that high HDAC1, HDAC2, HDAC4 and HDAC11 levels were significantly associated with unfavorable prognostic factors. Particularly, high HDAC4 expression was associated with high initial leukocyte count, T cell ALL and prednisone poor-response. siRNA-mediated inhibition of HDAC4 sensitized a T-ALL cell line to etoposide-induced cell death. In conclusion, our data point to HDAC4 as drug target in childhood ALL, especially in prednisone poor-responders.

Singh A, Happel C, Manna SK, et al.
Transcription factor NRF2 regulates miR-1 and miR-206 to drive tumorigenesis.
J Clin Invest. 2013; 123(7):2921-34 [PubMed] Article available free on PMC after 21/08/2015 Related Publications
The mechanisms by which deregulated nuclear factor erythroid-2-related factor 2 (NRF2) and kelch-like ECH-associated protein 1 (KEAP1) signaling promote cellular proliferation and tumorigenesis are poorly understood. Using an integrated genomics and ¹³C-based targeted tracer fate association (TTFA) study, we found that NRF2 regulates miR-1 and miR-206 to direct carbon flux toward the pentose phosphate pathway (PPP) and the tricarboxylic acid (TCA) cycle, reprogramming glucose metabolism. Sustained activation of NRF2 signaling in cancer cells attenuated miR-1 and miR-206 expression, leading to enhanced expression of PPP genes. Conversely, overexpression of miR-1 and miR-206 decreased the expression of metabolic genes and dramatically impaired NADPH production, ribose synthesis, and in vivo tumor growth in mice. Loss of NRF2 decreased the expression of the redox-sensitive histone deacetylase, HDAC4, resulting in increased expression of miR-1 and miR-206, and not only inhibiting PPP expression and activity but functioning as a regulatory feedback loop that repressed HDAC4 expression. In primary tumor samples, the expression of miR-1 and miR-206 was inversely correlated with PPP gene expression, and increased expression of NRF2-dependent genes was associated with poor prognosis. Our results demonstrate that microRNA-dependent (miRNA-dependent) regulation of the PPP via NRF2 and HDAC4 represents a novel link between miRNA regulation, glucose metabolism, and ROS homeostasis in cancer cells.

Giaginis C, Alexandrou P, Delladetsima I, et al.
Clinical significance of histone deacetylase (HDAC)-1, HDAC-2, HDAC-4, and HDAC-6 expression in human malignant and benign thyroid lesions.
Tumour Biol. 2014; 35(1):61-71 [PubMed] Related Publications
Histone deacetylases (HDACs) have been associated with human malignant tumor development and progression, and HDAC inhibitors are currently being explored as anticancer agents in clinical trials. The present study aimed to evaluate the clinical significance of HDAC-1, HDAC-2, HDAC-4, and HDAC-6 proteins' expression in human malignant and benign thyroid lesions. HDAC-1, HDAC-2, HDAC-4, and HDAC-6 proteins' expression was assessed immunohistochemically on paraffin-embedded thyroid tissues obtained from 74 patients with benign and malignant thyroid lesions. Enhanced HDAC-2 and HDAC-6 expression was significantly more frequently observed in malignant, compared to benign, thyroid lesions (p = 0.0042 and p = 0.0069, respectively). Enhanced HDAC-2, HDAC-4, and HDAC-6 expression was significantly more frequently observed in cases with papillary carcinoma compared to hyperplastic nodules (p = 0.0065, p = 0.0394, and p = 0.0061, respectively). In malignant thyroid lesions, HDAC-1, HDAC-4, and HDAC-6 expression was significantly associated with tumor size (p = 0.0169, p = 0.0056, and p = 0.0234, respectively); HDAC-2 expression with lymphatic and vascular invasion (p = 0.0299 and p = 0.0391, respectively); and HDAC-4 expression with capsular invasion (p = 0.0464). The cellular pattern of HDAC-1 and HDAC-2 distribution (nuclear vs. nuclear and cytoplasmic) presented a distinct discrimination between malignant and benign thyroid lesions (p = 0.0030 and p = 0.0028, respectively) as well as between papillary carcinoma and hyperplastic nodules (p = 0.0036 and p = 0.0028, respectively). HDAC-1, HDAC-2, HDAC-4, and HDAC-6 may be associated with the malignant thyroid transformation and could be considered as useful biomarkers and possible therapeutic targets in this neoplasia.

Yu SL, Lee DC, Son JW, et al.
Histone deacetylase 4 mediates SMAD family member 4 deacetylation and induces 5-fluorouracil resistance in breast cancer cells.
Oncol Rep. 2013; 30(3):1293-300 [PubMed] Related Publications
Histone deacetylases (HDACs) have been shown to play important roles in the regulation of chromatin remodeling by histone deacetylation, and their expression is induced in several types of cancer. In addition, they are known to be associated with resistance to anticancer drugs. However, the relevance of HDAC4 in chemoresistance remains unclear. Therefore, we investigated the interaction between HDAC4 expression and chemoresistance in breast cancer cells. We found that increased HDAC4 expression in MDA-MB-231 cells was associated with resistance to the anticancer drug 5-fluorouracil (5-FU). To verify these results, a cell line stably overexpressing HDAC4 was generated using MCF-7 cells (HDAC4OE). This cell line displayed increased 5-FU resistance, and HDAC4 knockdown in HDAC4OE cells restored 5-FU sensitivity. Consequently, we concluded that HDAC4 is a critical gene associated with 5‑FU chemoresistance. Further investigation using a microarray approach revealed that 355 genes were differentially expressed following HDAC4 overexpression. Based on functional annotation of the array results, HDAC4 overexpression was found to downregulate genes related to the transforming growth factor (TGF) β signaling pathway, including SMAD4, SMAD6, bone morphogenetic protein 6, inhibitor of DNA binding 1 and TGFβ2. We also found that HDAC4 expression regulates SMAD4 expression by inducing deacetylation of histone H3 in the SMAD4 promoter region. In addition, SMAD4 knockdown in MCF‑7 cells increased 5-FU resistance. In summary, our data suggest that HDAC4‑mediated deacetylation of the SMAD4 promoter may lead to 5-FU resistance in breast cancer cells.

De Cecco L, Berardi M, Sommariva M, et al.
Increased sensitivity to chemotherapy induced by CpG-ODN treatment is mediated by microRNA modulation.
PLoS One. 2013; 8(3):e58849 [PubMed] Article available free on PMC after 21/08/2015 Related Publications
We recently reported that peritumoral CpG-ODN treatment, activating TLR-9 expressing cells in tumor microenvironment, induces modulation of genes involved in DNA repair and sensitizes cancer cells to DNA-damaging cisplatin treatment. Here, we investigated whether this treatment induces modulation of miRNAs in tumor cells and their relevance to chemotherapy response. Array analysis identified 20 differentially expressed miRNAs in human IGROV-1 ovarian tumor cells from CpG-ODN-treated mice versus controls (16 down- and 4 up-regulated). Evaluation of the role of the 3 most differentially expressed miRNAs on sensitivity to cisplatin of IGROV-1 cells revealed significantly increased cisplatin cytotoxicity upon ectopic expression of hsa-miR-302b (up-modulated in our array), but no increased effect upon reduced expression of hsa-miR-424 or hsa-miR-340 (down-modulated in our array). Accordingly, hsa-miR-302b expression was significantly associated with time to relapse or overall survival in two data sets of platinum-treated ovarian cancer patients. Use of bio-informatics tools identified 19 mRNAs potentially targeted by hsa-miR-302b, including HDAC4 gene, which has been reported to mediate cisplatin sensitivity in ovarian cancer. Both HDAC4 mRNA and protein levels were significantly reduced in IGROV-1 cells overexpressing hsa-miR-302b. Altogether, these findings indicate that hsa-miR-302b acts as a "chemosensitizer" in human ovarian carcinoma cells and may represent a biomarker able to predict response to cisplatin treatment. Moreover, the identification of miRNAs that improve sensitivity to chemotherapy provides the experimental underpinning for their possible future clinical use.

Dehennaut V, Loison I, Dubuissez M, et al.
DNA double-strand breaks lead to activation of hypermethylated in cancer 1 (HIC1) by SUMOylation to regulate DNA repair.
J Biol Chem. 2013; 288(15):10254-64 [PubMed] Article available free on PMC after 21/08/2015 Related Publications
HIC1 (hypermethylated in cancer 1) is a tumor suppressor gene frequently epigenetically silenced in human cancers. HIC1 encodes a transcriptional repressor involved in the regulation of growth control and DNA damage response. We previously demonstrated that HIC1 can be either acetylated or SUMOylated on lysine 314. This deacetylation/SUMOylation switch is governed by an unusual complex made up of SIRT1 and HDAC4 which deacetylates and thereby favors SUMOylation of HIC1 by a mechanism not yet fully deciphered. This switch regulates the interaction of HIC1 with MTA1, a component of the NuRD complex and potentiates the repressor activity of HIC1. Here, we show that HIC1 silencing in human fibroblasts impacts the repair of DNA double-strand breaks whereas ectopic expression of wild-type HIC1, but not of nonsumoylatable mutants, leads to a reduced number of γH2AX foci induced by etoposide treatment. In this way, we demonstrate that DNA damage leads to (i) an enhanced HDAC4/Ubc9 interaction, (ii) the activation of SIRT1 by SUMOylation (Lys-734), and (iii) the SUMO-dependent recruitment of HDAC4 by SIRT1 which permits the deacetylation/SUMOylation switch of HIC1. Finally, we show that this increase of HIC1 SUMOylation favors the HIC1/MTA1 interaction, thus demonstrating that HIC1 regulates DNA repair in a SUMO-dependent way. Therefore, epigenetic HIC1 inactivation, which is an early step in tumorigenesis, could contribute to the accumulation of DNA mutations through impaired DNA repair and thus favor tumorigenesis.

Algamas-Dimantov A, Yehuda-Shnaidman E, Peri I, Schwartz B
Epigenetic control of HNF-4α in colon carcinoma cells affects MUC4 expression and malignancy.
Cell Oncol (Dordr). 2013; 36(2):155-67 [PubMed] Related Publications
BACKGROUND: We previously found that enhanced expression of hepatocyte nuclear factor 4α (HNF-4α) is associated with hyper-proliferation of colon carcinoma cells. Here, the effect of histone deacetylase (HDAC) inhibitors on proliferation and the expression of HNF-4α and its downstream target genes were assessed in HM7, LS174T, HT29 and Caco-2 colon carcinoma cell lines.
RESULTS: HNF-4α expression was found to vary in the different colon carcinoma cell lines tested, being highest in HM7. Additionally, a direct correlation with proliferation was observed. In HM7 cells, the weak HDAC inhibitor butyrate significantly inhibited the transcription of HNF-4α, its downstream target gene MUC4, and genes associated with proliferation, including the proliferating cell nuclear antigen gene PCNA. siRNA-mediated silencing of HNF-4α exerted an effect similar to butyrate on HM7 cell proliferation. The stronger HDAC inhibitor trichostatin A (TSA) exerted an effect similar to that of siRNA-mediated HNF-4α silencing and, concomitantly, inhibited the expression of the transcription factor gene SP1. Also, siRNA-mediated silencing of HDAC3 and HDAC4 reduced HNF-4α expression. Chromatin immunoprecipitation (ChIP) assays revealed that TSA induces hyperacetylation of histones H3 and H4 and, concomitantly, inhibits SP1 binding to the HNF-4α promoter. Subsequent electromobility shift assays supported these latter findings.
CONCLUSIONS: HNF-4α transcriptional expression and activity are tightly controlled by epigenetic mechanisms. HDAC inhibitor targeting of HNF-4α may serve as an effective treatment for advanced colon carcinomas, since downstream cancer-associated target genes such as MUC4 are significantly down-regulated by this treatment.

Broyl A, Kuiper R, van Duin M, et al.
High cereblon expression is associated with better survival in patients with newly diagnosed multiple myeloma treated with thalidomide maintenance.
Blood. 2013; 121(4):624-7 [PubMed] Related Publications
Recently, cereblon (CRBN) expression was found to be essential for the activity of thalidomide and lenalidomide. In the present study, we investigated whether the clinical efficacy of thalidomide in multiple myeloma is associated with CRBN expression in myeloma cells. Patients with newly diagnosed multiple myeloma were included in the HOVON-65/GMMG-HD4 trial, in which postintensification treatment in 1 arm consisted of daily thalidomide (50 mg) for 2 years. Gene-expression profiling, determined at the start of the trial, was available for 96 patients who started thalidomide maintenance. In this patient set, increase of CRBN gene expression was significantly associated with longerprogression-free survival (P = .005). In contrast, no association between CRBN expression and survival was observed in the arm with bortezomib maintenance. We conclude that CRBN expression may be associated with the clinical efficacy of thalidomide. This trial has been registered at the Nederlands Trial Register (www.trialregister.nl) as NTR213; at the European Union Drug Regulating Authorities Clinical Trials (EudraCT) as 2004-000944-26; and at the International Standard Randomized Controlled Trial Number (ISRCTN) as 64455289.

Sandhu SK, Volinia S, Costinean S, et al.
miR-155 targets histone deacetylase 4 (HDAC4) and impairs transcriptional activity of B-cell lymphoma 6 (BCL6) in the Eμ-miR-155 transgenic mouse model.
Proc Natl Acad Sci U S A. 2012; 109(49):20047-52 [PubMed] Article available free on PMC after 21/08/2015 Related Publications
Multiple studies have established that microRNAs (miRNAs) are involved in the initiation and progression of cancer. Notably, miR-155 is one of the most overexpressed miRNAs in several solid and hematological malignancies. Ectopic miR-155 expression in mice B cells (Eμ-miR-155 transgenic mice) has been shown to induce pre-B-cell proliferation followed by high-grade lymphoma/leukemia. Loss of miR-155 in mice resulted in impaired immunity due to defective T-cell-mediated immune response. Here we provide a mechanistic insight into miR-155-induced leukemogenesis in the Eμ-miR-155 mouse model through genome-wide transcriptome analysis of naïve B cells and target studies. We found that a key transcriptional repressor and proto-oncogene, Bcl6 is significantly down-regulated in Eμ-miR-155 mice. The reduction of Bcl6 subsequently leads to de-repression of some of the known Bcl6 targets like inhibitor of differentiation (Id2), interleukin-6 (IL6), cMyc, Cyclin D1, and Mip1α/ccl3, all of which promote cell survival and proliferation. We show that Bcl6 is indirectly regulated by miR-155 through Mxd1/Mad1 up-regulation. Interestingly, we found that miR-155 directly targets HDAC4, a corepressor partner of BCL6. Furthermore, ectopic expression of HDAC4 in human-activated B-cell-type diffuse large B-cell lymphoma (DLBCL) cells results in reduced miR-155-induced proliferation, clonogenic potential, and increased apoptosis. Meta-analysis of the diffuse large B-cell lymphoma patient microarray data showed that miR-155 expression is inversely correlated with Bcl6 and Hdac4. Hence this study provides a better understanding of how miR-155 causes disruption of the BCL6 transcriptional machinery that leads to up-regulation of the survival and proliferation genes in miR-155-induced leukemias.

Niegisch G, Knievel J, Koch A, et al.
Changes in histone deacetylase (HDAC) expression patterns and activity of HDAC inhibitors in urothelial cancers.
Urol Oncol. 2013; 31(8):1770-9 [PubMed] Related Publications
OBJECTIVE: To determine histone deacetylase (HDAC) isoenzyme expression patterns in urothelial cancer tissues and cell lines and investigate their potential to predict the efficacy of the HDAC inhibitor vorinostat.
MATERIALS AND METHODS: Expression of HDAC mRNAs was determined by quantitative RT-PCR in 18 urothelial cancer cell lines (UCC), normal uroepithelial controls (NUC), 24 urothelial cancer tissues, and 12 benign controls. Results were compared with published microarray data. Effects of pan-HDAC inhibitor vorinostat and on UCCs were determined by viability and apoptosis assays, cell cycle analysis, and measurements of p21(CIP1), thymidylate synthase (TS), and EZH2. In addition, protein expression levels of HDACs were investigated in UCCs.
RESULTS: Prominent changes in UCCs were HDAC2 and/or HDAC8 up-regulation in 11 of 18 cell lines and decreased expression of HDAC4, HDAC5, and/or HDAC7 mRNA in 15 of 18 cell lines. In cancer tissues, HDAC8 was likewise significantly up-regulated (P = 0.002), whereas HDAC2 up-regulation was detected only in a subset of tumors (9/24, P = 0.085). Overexpression of HDAC2 and HDAC8 mRNA did not correspond with the protein level. Vorinostat induced G2/M arrest, an increase in the sub-G1 fraction, up-regulation of p21, and down-regulation of TS in all UCC. Effects on EZH2 and PARP cleavage as well as activation of caspase 3/7 differed between cell lines. Associations between the overall sensitivity to the pan-HDACi vorinostat and overexpression of HDAC2 and HDAC8 mRNA were not observed.
CONCLUSIONS: In urothelial cancer, up-regulation of HDAC2 and HDAC8 and down-regulation of HDAC4, HDAC5, and HDAC7 mRNA are common findings. The treatment effect of the pan-HDAC inhibitor vorinostat was variable in UCCs and up-regulation of HDAC2 and HDAC8 was not predictive for treatment response. Whether selective targeting of HDAC2, HDAC8, or other HDACs deregulated in urothelial cancer (e.g., HDAC4, HDAC5, and HDAC7) result in a more consistent treatment response needs further investigation.

Cahill N, Bergh AC, Kanduri M, et al.
450K-array analysis of chronic lymphocytic leukemia cells reveals global DNA methylation to be relatively stable over time and similar in resting and proliferative compartments.
Leukemia. 2013; 27(1):150-8 [PubMed] Related Publications
In chronic lymphocytic leukemia (CLL), the microenvironment influences gene expression patterns; however, knowledge is limited regarding the extent to which methylation changes with time and exposure to specific microenvironments. Using high-resolution 450K arrays, we provide the most comprehensive DNA methylation study of CLL to date, analyzing paired diagnostic/follow-up samples from IGHV-mutated/untreated and IGHV-unmutated/treated patients (n=36) and patient-matched peripheral blood and lymph node samples (n=20). On an unprecedented scale, we revealed 2239 differentially methylated CpG sites between IGHV-mutated and unmutated patients, with the majority of sites positioned outside annotated CpG islands. Intriguingly, CLL prognostic genes (for example, CLLU1, LPL, ZAP70 and NOTCH1), epigenetic regulator (for example, HDAC9, HDAC4 and DNMT3B), B-cell signaling (for example, IBTK) and numerous TGF-β and NF-κB/TNF pathway genes were alternatively methylated between subgroups. Contrary, DNA methylation over time was deemed rather stable with few recurrent changes noted within subgroups. Although a larger number of non-recurrent changes were identified among IGHV-unmutated relative to mutated cases over time, these equated to a low global change. Similarly, few changes were identified between compartment cases. Altogether, we reveal CLL subgroups to display unique methylation profiles and unveil methylation as relatively stable over time and similar within different CLL compartments, implying aberrant methylation as an early leukemogenic event.

Beaver LM, Yu TW, Sokolowski EI, et al.
3,3'-Diindolylmethane, but not indole-3-carbinol, inhibits histone deacetylase activity in prostate cancer cells.
Toxicol Appl Pharmacol. 2012; 263(3):345-51 [PubMed] Article available free on PMC after 21/08/2015 Related Publications
Increased consumption of cruciferous vegetables is associated with a reduced risk of developing prostate cancer. Indole-3-carbinol (I3C) and 3,3'-diindolylmethane (DIM) are phytochemicals derived from cruciferous vegetables that have shown promise in inhibiting prostate cancer in experimental models. Histone deacetylase (HDAC) inhibition is an emerging target for cancer prevention and therapy. We sought to examine the effects of I3C and DIM on HDACs in human prostate cancer cell lines: androgen insensitive PC-3 cells and androgen sensitive LNCaP cells. I3C modestly inhibited HDAC activity in LNCaP cells by 25% but no inhibition of HDAC activity was detected in PC-3 cells. In contrast, DIM significantly inhibited HDAC activity in both cell lines by as much as 66%. Decreases in HDAC activity correlated with increased expression of p21, a known target of HDAC inhibitors. DIM treatment caused a significant decrease in the expression of HDAC2 protein in both cancer cell lines but no significant change in the protein levels of HDAC1, HDAC3, HDAC4, HDAC6 or HDAC8 was detected. Taken together, these results show that inhibition of HDAC activity by DIM may contribute to the phytochemicals' anti-proliferative effects in the prostate. The ability of DIM to target aberrant epigenetic patterns, in addition to its effects on detoxification of carcinogens, may make it an effective chemopreventive agent by targeting multiple stages of prostate carcinogenesis.

Ahn MY, Kang DO, Na YJ, et al.
Histone deacetylase inhibitor, apicidin, inhibits human ovarian cancer cell migration via class II histone deacetylase 4 silencing.
Cancer Lett. 2012; 325(2):189-99 [PubMed] Related Publications
This study examined the molecular mechanisms of apicidin in the modulation of human ovarian cancer SKOV-3 cells invasion and migration. Apicidin markedly decreased histone deacetylase 4 (HDAC4) expression and blocked cell migration and invasion. Cell migration was inhibited via down-regulation of matrix metalloproteinase-2 (MMP-2) and up-regulation of RECK in the HDAC4-blocked SKOV-3 cells. Apicidin significantly suppressed the binding of HDAC4 to Sp1 binding elements of the RECK promoter via repression of HDAC4. In an in vivo model, apicidin suppressed the growth of transplanted SKOV-3 cells by down-regulating HDAC4 and MMP-2. Apicidin may potentially be used as an anti-cancer agent for inhibition of cancer cell migration and invasion through the repression of MMP-2 which is related to the reduction of HDAC4.

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