This study aimed to detect serum miR-203 expression levels in AML and explore its potential clinical significance. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was performed to measure the serum miR-203 levels in 134 patients with AML and 70 healthy controls. The results demonstrated that serum miR-203 expression was significantly reduced in AML patients compared with healthy controls. Receiver operating characteristic curve (ROC) analysis revealed miR-203 could distinguish AML cases from normal controls. Low serum miR-203 levels were associated with worse clinical features, as well as poorer overall survival and relapse free survival of AML patients. Moreover, multivariate analysis confirmed low serum miR-203 expression to be an independent unfavorable prognostic predictor for AML. The bioinformatics analysis showed that the downstream genes and pathways of miR-203 was closely associated with tumorigenesis. Downregulation of miR-203 in AML cell lines upregulated the expression levels of oncogenic promoters such as CREB1, SRC and HDAC1. Thus, these findings demonstrated that serum miR-203 might be a promising biomarker for the diagnosis and prognosis of AML.

BACKGROUND: In a previous study, we demonstrated that deficiency of microRNA-449a (miR-449a) promoted colorectal tumorigenesis. In this study, the significance of miR-449a in the prognosis and relationship with HDAC1 in colorectal cancer was examined.
MATERIALS AND METHODS: Seventy-two patients with colorectal cancer and 16 patients with colorectal liver metastasis who underwent surgery were included. miR-449a expression in tumor tissue of resected specimen was investigated by real-time polymerase chain reaction and histone deacetylase 1 (HDAC1) expression was examined by immunohistochemistry.
RESULTS: Lymphovascular invasion and increased serum carcinoembryonic antigen levels were seen more frequent in patients with low miR-449a expression. Patients with low miR-449a expression were found to have a poorer prognosis than those with high expression. Vascular invasion, increased serum carbohydrate antigen 19-9 level and low miR-449a were associated with poorer disease-free survival. miR-449a expression was lower in metastatic liver tumor compared to primary tumor. HDAC1 positivity was higher in patients with low miR-449a.
CONCLUSION: miR-449a level might be a prognostic indicator for colorectal cancer and miR-449a might regulate HDAC1 expression.

Aberrant epigenetic modifications are responsible for tumor development and cancer progression; however, readily reversible. Bioactive molecules from diets are promising to cure cancer by modulating epigenetic marks and changing immune response. These compounds specifically target the activity of DNMTs and HDACs to cure various human cancers. In view of this, we investigated the anticancer and epigenetic regulatory activities of an edible-plant Paederia foetida. The efficacy of methanolic extract of P. foetida leaves (MEPL) was tested for the modulation of epigenetic factors in gene silencing, i.e. DNMT and HDAC and expression pattern of certain tumor-suppressor genes. After treatment of prostate cancer cells (PC-3 and DU-145) with MEPL, lupeol and β-sitosterol; induction of apoptosis, decrease in cellular-viability and inhibition of cellular-migration were noticed. Simultaneously there was inhibition of DNMT1, HDACs and pro-inflammatory, IL-6, IL1-β, TNF-α and anti-inflammatory, IL-10 genes in cancer and THP1 cell lines. The DNMT1 protein content, enzyme activity and Bcl2 expression decreased significantly; however, expression of E-cadherin (CDH1) and pro-apoptotic gene Bax increased significantly after the treatment of cells with drugs. We conclude plant-derived compounds can be considered to target epigenetic machineries involved with malignant transformation and can open new avenues for cancer therapeutics provoking immune response.

Since imatinib (Glivec or Gleevec) has been used to target the BCR-ABL fusion protein, chronic myeloid leukemia (CML) has become a manageable chronic disease with long-term survival. However, 15%-20% of CML patients ultimately develop resistance to imatinib and then progress to an accelerated phase and eventually to a blast crisis, limiting treatment options and resulting in a poor survival rate. Thus, we investigated whether histone deacetylase inhibitors (HDACis) could be used as a potential anticancer therapy for imatinib-resistant CML (IR-CML) patients. By applying a noninvasive apoptosis detection sensor (NIADS), we found that panobinostat significantly enhanced cell apoptosis in K562 cells. A further investigation showed that panobinostat induced apoptosis in both K562 and imatinib-resistant K562 (IR-K562) cells mainly via H3 and H4 histone acetylation, whereas panobinostat targeted cancer stem cells (CSCs) in IR-K562 cells. Using CRISPR/Cas9 genomic editing, we found that HDAC1 and HDAC2 knockout cells significantly induced cell apoptosis, indicating that the regulation of HDAC1 and HDAC2 is extremely important in maintaining K562 cell survival. All information in this study indicates that regulating HDAC activity provides therapeutic benefits against CML and IR-CML in the clinic.

Accumulating evidence suggests that long noncoding RNA (lncRNA) plays important regulatory roles in cancer biology. However, the involvement of lncRNA in colorectal carcinoma progression remains largely unknown, especially in colorectal carcinoma metastasis. In this study, we investigated the changes in lncRNA expression in colorectal carcinoma and identified a new lncRNA, the antisense transcript of SATB2 (

Colorectal cancer (CRC) is one of the most common cancer diagnoses. Histone deacetylase (HDAC) overactivity in CRC could promote cancer progression. HDAC1, a member of the HDAC family, is found aberrantly expressed in CRC, but it remains unclear whether the expression of HDAC1 can be regulated by microRNA. In the present study, we confirmed the overexpression status of HDAC1 in CRC tissues and cell lines, and its overexpression could promote CRC cell proliferation and invasion

BACKGROUND: Aberrant EVI1 expression is frequently reported in cancer studies; however, its role in nasopharyngeal carcinoma (NPC) has not been examined in detail. The aim of the present study is to investigate the involvement of EVI1 in progression and prognosis of NPC.
METHODS: RT-PCR, immunohistochemistry and western blot assays were used to examine the expression of EVI1 in NPC tissues and cell lines. Fluorescence in situ hybridization assay was used to examine the amplification of EVI1 in NPC tissues. The biological effect of EVI1 was determined by both in vitro and in vivo studies. The dual-luciferase reporter assay was performed to confirm that EVI1 bind at E-cadherin andβ-catenin promoters. The ChIP, EMSA, and coimmunoprecipitation combined with mass spectrometry assays were used to analyze the EVI1 regulated proteins.
RESULTS: EVI1 expression level was up-regulated in NPC tissues and cell lines. EVI1 was amplificated in NPC tissues. We observed that EVI1 down-regulation decreased the cell proliferation and invasive capacity of NPC cells in vitro and in vivo. EVI1, snail, and HDAC1 formed a co-repressor complex to repress E-cadherin expression and ultimately contributed to epithelial mesenchymal transition (EMT) phenotype in NPC cells. In another way, EVI1 directly bound at β-catenin promoter and activated its expression. β-catenin mediated EVI1's function on cancer stem cells (CSCs) properties. EVI1 up-regulation predicted unfavorable prognosis and contributed to chemo/radio-resistance in NPC cells. Finally, we constructed arsenic trioxide-loaded nanoparticles (ALNPs) and revealed that ALNPs exerted anti-tumor effect in NPC cells.
CONCLUSIONS: Our data indicated that EVI1 played an oncogenic role in NPC growth and metastasis and that EVI1 might serve as a novel molecular target for the treatment of NPC.

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. The most important reason for the occurrence of HCC is hepatitis C or B infection. Moreover, genetic factors play an important role in the tumorigenesis of HCC. Here, we demonstrated that Krüppel-like factor 2 (KLF2) expression was downregulated in HCC samples compared with adjacent tissues. Additionally, KLF2 was shown to inhibit the growth, migration and colony-formation ability of liver cancer cells. Further mechanistic studies revealed that KLF2 can compete with Gli1 for interaction with HDAC1 and restrains Hedgehog signal activation. Together, our results suggest that KLF2 has potential as a diagnostic biomarker and therapeutic target for the treatment of HCC.

Anaplastic thyroid carcinoma (ATC) and squamous thyroid carcinoma (STC) are both rare and advanced thyroid malignancies with a very poor prognosis and an average median survival time of 5 months and less than 20% of affected patients are alive 1 year after diagnosis. The clinical management of both ATC and STC is very similar because they are not particularly responsive to radiotherapy and chemotherapy. This inspired us to explore a novel and effective clinically approved therapy for ATC treatment. Histone deacetylase inhibitor (HDACi) drugs are recently FDA-approved drug for malignancies, especially for blood cell cancers. Therefore, we investigated whether an HDACi drug acts as an effective anticancer drug for advanced thyroid cancers. Cell viability analysis of panobinostat treatment demonstrated a significant IC50 of 0.075 µM on SW579 STC cells. In addition, panobinostat exposure activated histone acetylation and triggered cell death mainly through cell cycle arrest and apoptosis-related protein activation. Using CRISPR/Cas9 to knock out

BACKGROUND: Defects in the type and degree of cellular glycosylation impact oncogenesis on multiple levels. Although the type of glycosylation is determined by protein sequence encoded by the genome, the extent and modifications of glycosylation depends on the activity of biosynthetic enzymes and recent data suggests that the glycome is also subject to epigenetic regulation. This study focuses on the ability of HDAC inhibition to alter glycosylation and to lead to pro-oncogenic alterations in the glycome as assessed by metastatic potential and chemoresistance.
METHODS: Epigenetically plastic SW13 adrenocortical carcinoma cells were treated with FK228, an HDAC inhibitor with high affinity for HDAC1 and, to a lesser extent, HDAC2. In comparing HDAC inhibitor treated and control cells, differential expression of glycome-related genes were assessed by microarray. Differential glycosylation was then assessed by lectin binding arrays and the ability of cellular proteins to bind to glycans was assessed by glycan binding arrays. Differential sensitivity to paclitaxel, proliferation, and MMP activity were also assessed.
RESULTS: Treatment with FK228 alters expression of enzymes in the biosynthetic pathways for a large number of glycome related genes including enzymes in all major glycosylation pathways and several glycan binding proteins. 84% of these differentially expressed glycome-related genes are linked to cancer, some as prognostic markers and others contributing basic oncogenic functions such as metastasis or chemoresistance. Glycan binding proteins also appear to be differentially expressed as protein extracts from treated and untreated cells show differential binding to glycan arrays. The impact of differential mRNA expression of glycosylation enzymes was documented by differential lectin binding. However, the assessment of changes in the glycome is complicated by the fact that detection of differential glycosylation through lectin binding is dependent on the methods used to prepare samples as protein-rich lysates show different binding than fixed cells in several cases. Paralleling the alterations in the glycome, treatment of SW13 cells with FK228 increases metastatic potential and reduces sensitivity to paclitaxel.
CONCLUSIONS: The glycome is substantially altered by HDAC inhibition and these changes may have far-reaching impacts on oncogenesis.

BACKGROUND: The Slug-E-cadherin axis plays a critical role in non-small-cell lung cancers (NSCLCs) where aberrant upregulation of Slug promotes cancer metastasis. Now, the post-translational modifications of Slug and their regulation mechanisms still remain unclear in lung cancer. Hence, exploring the protein linkage map of Slug is of great interest for investigating the scenario of how Slug protein is regulated in lung cancer metastasis.
METHODS: The Slug associated proteins, Ubc9 and SUMO-1, were identified using yeast two-hybrid screening; and in vitro SUMOylation assays combined with immunoprecipitation and immunoblotting were performed to explore the detail events and regulations of Slug SUMOylation. The functional effects of SUMOylation on Slug proteins were examined by EMSA, reporter assay, ChIP assay, RT-PCR, migration and invasion assays in vitro, tail vein metastatic analysis in vivo, and also evaluated the association with clinical outcome of NSCLC patients.
RESULTS: Slug protein could interact with Ubc9 and SUMO-1 and be SUMOylated in cells. Amino acids 130-212 and 33-129 of Slug are responsible for its binding to Ubc9 and protein inhibitor of activated STAT (PIAS)y, respectively. SUMOylation could enhance the transcriptional repression activity of Slug via recruiting more HDAC1, resulting in reduced expression of downstream Slug target genes and enhanced lung cancer metastasis. In addition, hypoxia could increase Slug SUMOylation through attenuating the interactions of Slug with SENP1 and SENP2. Finally, high expression Slug and Ubc9 levels were associated with poor overall survival among NSCLC patients.
CONCLUSIONS: Ubc9/PIASy-mediated Slug SUMOylation and subsequent HDAC1 recruitment may play a crucial role in hypoxia-induced lung cancer progression, and these processes may serve as therapeutic targets for NSCLC.

BACKGROUND: B7 homolog 1 (B7-H1) overexpression on tumor cells is an important mechanism of immune evasion in gastric cancer (GC). Elucidation of the regulation of B7-H1 expression is urgently required to guide B7-H1-targeted cancer therapy. Interferon gamma (IFN-γ) is thought to be the main driving force behind B7-H1 expression, and epigenetic factors including histone acetylation are recently linked to the process. Here, we investigated the potential role of histone deacetylase (HDAC) in IFN-γ-induced B7-H1 expression in GC. The effect of Vorinostat (SAHA), a small molecular inhibitor of HDAC, on tumor growth and B7-H1 expression in a mouse GC model was also evaluated.
RESULTS: RNA-seq data from The Cancer Genome Atlas revealed that expression of B7-H1, HDAC1-3, 6-8, and 10 and SIRT1, 3, 5, and 6 was higher, and expression of HDAC5 and SIRT4 was lower in GC compared to that in normal gastric tissues; that HDAC3 and HDAC1 expression level significantly correlated with B7-H1 in GC with a respective r value of 0.42 (p < 0.001) and 0.21 (p < 0.001). HDAC inhibitor (Trichostatin A, SAHA, and sodium butyrate) pretreatment suppressed IFN-γ-induced B7-H1 expression on HGC-27 cells. HDAC1 and HDAC3 gene knockdown had the same effect. SAHA pretreatment or HDAC knockdown resulted in impaired IFN-γ signaling, demonstrated by the reduction of JAK2, p-JAK1, p-JAK2, and p-STAT1 expression and inefficient STAT1 nuclear translocation. Furthermore, SAHA pretreatment compromised IFN-γ-induced upregulation of histone H3 lysine 9 acetylation level in B7-H1 gene promoter. In the grafted mouse GC model, SAHA treatment suppressed tumor growth, inhibited B7-H1 expression, and elevated the percentage of tumor-infiltrating CD8+ T cells.
CONCLUSION: HDAC is indispensable for IFN-γ-induced B7-H1 in GC. The study suggests the possibility of targeting B7-H1 using small molecular HDAC inhibitors for cancer treatment.

Regulation of transcription is a key process in cellular homeostasis. It depends on regulators that either repress or stimulate the transcription of genes, therefore controlling different biological functions. The Nuclear Receptor Corepressor 1 (NCOR1) is one of those co-repressors that regulate the transcription by facilitating the recruitment of HDAC1, 2, 3, 4, 5 and 7. In our article, by using an in silico approach, we evaluate the mutational status of NCOR1 in breast and lung tumors. We identified that NORC1 is mutated in more than 3% of breast tumors and lung adenocarcinomas and linked this fact with detrimental outcome in some subtypes, particularly in those that are hormone receptor negative. In addition to these findings, as mutations in this gene are deleterious, we confirmed that high levels of this gene were linked with good prognosis in the same tumor subtypes. Findings in the same direction were identified in lung adenocarcinomas, with mutations associated with detrimental prognosis and high expression with better outcome. In conclusion, hereby we describe the presence and prognostic role of mutations in the NCOR1 gene in hormone receptor negative breast and lung adenocarcinomas, and we also confirm that NCOR1 is a tumor suppressor gene. Further studies should be performed to explore therapeutic mechanisms to restore its function.

GM2-synthase produces sialic acid-containing glycosphingolipids called gangliosides, and its mRNA overexpression and the gangliosides it generates are linked to tumor progression, migration, and suppression of tumor-specific host immune responses. However, the mechanism underlying GM2-synthase de-repression in renal cell carcinoma (RCC) is poorly understood. Here, we demonstrate that higher GM2-synthase mRNA expression levels in various cancer cells and in human RCC tumors correlate with higher histone acetylation levels (H3K9, H3K14, or both) at region +38/+187 relative to the transcription start site (TSS) of the GM2-synthase gene than in normal kidney epithelial (NKE) cells or healthy adjacent tissues. An increase in GM2-synthase mRNA expression in cells treated with a histone deacetylase (HDAC) inhibitor was accompanied by increased histone acetylation levels at this promoter region. DNA methylation around the TSS was absent in both RCC cell lines and NKE cells. Of note, both the transcription factor Sp1 and corepressor HDAC1 associated with the +38/+187 region when the GM2-synthase gene was repressed in NKE and tumor-adjacent tissues, indicating plausible site-specific repressive roles of HDAC1 and Sp1 in GM2-synthase mRNA expression. Site-directed mutagenesis of the Sp1-binding site within the +38/+187 region relieved repressed luciferase activity of this region by limiting HDAC1 recruitment. Moreover, Sp1 or HDAC1 knock down increased GM2-synthase transcription, and butyrate-mediated activation of GM2-synthase mRNA expression in SK-RC-45 cells was accompanied by Sp1 and HDAC1 loss from the +38/+187 region. Taken together, we have identified an epigenetic mechanism for the de-repression of the GM2-synthase gene in RCC.

Chronic inflammation is known to contribute to tumor initiation and cancer progression. In breast tissue, the core circadian gene Period (PER)2 plays a critical role in mammary gland development and possesses tumor suppressor function. Interleukin (IL)-6 and C-C motif chemokine ligand (CCL) 2 are among the most abundant cytokines in the inflammatory microenvironment. We found that acute stimulation by IL-6/CCL2 reduced PER2 expression in non-tumorigenic breast epithelial cells. Longer term exposure to IL-6/CCL2 suppressed PER2 to an even lower level. IL-6 activated STAT3/NFκB p50 signaling to recruit HDAC1 to the PER2 promoter. CCL2 activated the PI3K/AKT pathway to promote ELK-1 cytoplasm-to-nucleus translocation, recruit HDAC1 to the proximal PER2 promoter and facilitate DNMT3-EZH2-PER2 promoter association. Ectopic expression of PER2 inhibited IL-6 or CCL2 induced mammosphere forming ability and reduced sphere size indicating that PER2 repression in breast epithelial cells can be crucial to activate tumorigenesis in an inflammatory microenvironment. The diminished expression of PER2 can be observed over a time scale of hours to weeks following IL-6/CCL2 stimulation suggesting that PER2 suppression occurs in the early stage of the interaction between an inflammatory microenvironment and normal breast epithelial cells. These data show new mechanisms by which mammary cells interact with a cancerous microenvironment and provide additional evidence that PER2 expression contributes to breast tumorigenesis.

Chlorpyrifos (CPF) is an organophosphorus pesticide used for agricultural pest control all over the world. We have previously demonstrated that environmental concentrations of this pesticide alter mammary gland histological structure and hormonal balance in rats chronically exposed. In this work, we analyzed the effects of CPF on mammary tumors development. Our results demonstrated that CPF increases tumor incidence and reduces latency of NMU-induced mammary tumors. Although no changes were observed in tumor growth rate, we found a reduced steroid hormone receptor expression in the tumors of animals exposed to the pesticide. Moreover, we analyzed the role of epigenetic mechanisms in CPF effects. Our results indicated that CPF alters HDAC1 mRNA expression in mammary gland, although no changes were observed in DNA methylation. In summary, we demonstrate that the exposure to CPF promotes mammary tumors development with a reduced steroid receptors expression. It has also been found that CPF affects HDAC1 mRNA levels in mammary tissue pointing that CPF may act as a breast cancer risk factor.

Gastric cancer (GC) development can be attributed to several risk factors including atrophic gastritis (AG), intestinal metaplasia (IM), and the presence of Helicobacter pylori (HP). Also, histone modification is an epigenetic mechanism that plays a pivotal role in GC carcinogenesis. In this preliminary study, we aimed to describe the expression profiles of histone modification in the AG, IM, and GC patient groups. A total of 80 patients with AG (n = 27), IM (n = 25), and GC (n = 28) with an additional 20 control subjects were included in the study. Expression profiles of three histone phosphorylation genes (PAK1, NEK6, and AURKA) and five histone deacetylation genes (HDACs 1, 2, 3, 5, and 7) were examined based on the results of Real Time qPCR method. It was observed that AURKA and HDAC2 genes were significantly overexpressed in all groups compared to the control (P < 0.05). In GC patients, overexpression of HDAC2 gene was detected in the absence of metastasis, and overexpression of AURKA, HDAC2, and NEK6 genes was detected in the presence of metastasis. When cancer involvements were compared, significant overexpression of the HDAC2 gene was noted in overall and corpus involvements (P < 0.05). In addition, overexpression of AURKA, NEK6, HDAC1, and HDAC2 genes and underexpression of HDAC5 gene were detected in the antrum involvement (P < 0.05). In conclusion, decreased expression of HDAC5 in GC is reported for the first time in this study, while supporting the existing literature in AURKA, NEK6, HDAC1, and HDAC2 up regulations during GC development.

AIMS: The aim of this study was to investigate the combinatorial effects of IM and a novel HDAC inhibitor AR-42 on the proliferation, apoptosis, cell cycle arrest, migration and invasion of CML cells, and to explore the underlying mechanisms.
MAIN METHODS: We assessed the ability of the pan-HDAC inhibitor AR-42 and IM, to synergistically kill CML cells by survival, apoptosis, cell cycle, migration and invasion assays in vitro. We also assessed the HDAC1 expression by Western blot and real-time PCR. Synergy was calculated using combinatorial indices as determined by CalcuSyn.
KEY FINDINGS: We found that Combining AR-42 with IM synergistically inhibited CML cell proliferation, enhanced cell apoptosis, induced cell cycle arrest, and decreased migration and invasion. The expression of HDAC1 in K562R cells was higher than that in K562 cells. AR-42 enhanced IM-induced HDAC1 expression inhibition in K562 and K562R cells. Importantly, HDAC1 overexpression partly reversed the apoptosis, G2/M phase arrest, migration and invasion of K562 cells induced by the combination of IM with AR-42. Moreover, HDAC1 knockdown partly promoted K562R cell apoptosis and G2/M phase arrest, migration and invasion induced by IM in combination with AR-42.
SIGNIFICANCE: In conclusion, AR-42 may increase the sensitivity of CML cells to IM and reverse IM resistance by regulating HDAC1 expression. This study provides new insights into the effects of combined therapy using IM and pan-HDAC inhibitor AR-42, paving the way for overcoming IM resistance in clinical practice.

BACKGROUND/AIMS: Cisplatin-based treatment is first-line chemotherapy for several cancers including ovarian cancer. The development of cisplatin resistance results in treatment failure, but the underlying mechanisms are not fully understood. Histone deacetylases (HDACs) are a large family of enzymes that deacetylate lysine residues on histones and non-histone proteins. High expression of HDAC1 is associated with poor outcomes in ovarian cancer. Furthermore, resistance to chemotherapeutic agents is associated with HDAC1 overexpression in ovarian cancer cells. The goals of this study were to determine whether targeting HDAC1 can sensitize ovarian cancer cells to cisplatin and to explore the underlying mechanisms.
METHODS: Small interfering RNA (siRNA)-targeting HDAC1 was designed to silence HDAC1 in the cisplatin-resistant ovarian cancer cell line A2780CDDP and its cisplatin-sensitive cell line A2780. The effects of targeting HDAC1 on cell viability assay, colony formation, and apoptosis were detected. c-Myc re-expression or miR-34a inhibitors were used to examine the relationship among HDAC1, c-Myc, and miR-34a expression, which was assessed by western blot analysis and quantitative reverse transcription PCR. We established stable transfectants of A2780CDDP/HDAC1 short hairpin RNA (shRNA) and A2780/HDAC1 shRNA. The therapeutic effectiveness of cisplatin in murine xenograft models was assessed following shRNA-mediated HDAC1 silencing in A2780CDDP and A2780 cells. The mechanism of cell death was studied in tumor sections obtained from different mouse tumors.
RESULTS: In cisplatin-resistant A2780CDDP cells, HDAC1 knockdown by siRNA suppressed cell proliferation, and increased apoptosis and chemosensitivity by downregulating c-Myc and upregulating miR-34a. In cisplatin-sensitive A2780 cells, HDAC1 knockdown did not affect cell proliferation and apoptosis. Cisplatin treatment activated HDAC1 and c-Myc and inactivated miR-34a. Inhibition of HDAC1 with siRNA reduced c-Myc expression, increased miR-34a expression, and sensitized A2780 cells to cisplatin-induced apoptosis. c-Myc re-expression or miR-34a targeting by miR-34a inhibitors protected cells from apoptosis or reversed cisplatin resistance following HDAC1 knockdown or/and cisplatin exposure. Finally, in vivo studies showed that targeting HDAC1 inhibited A2780CDDP-induced xenograft tumor growth but not A2780-induced xenograft tumor growth. Targeting HDAC1 sensitized both A2780- and A2780CDDP-induced xenograft tumors to cisplatin treatment.
CONCLUSIONS: Upregulation of HDAC1 is a crucial event in the development of drug resistance to current treatments in ovarian cancer. Thus, targeting HDAC1 by enhancing c-Myc-dependent miR-34a expression might be an effective strategy for increasing the efficacy of cisplatin treatment.

It has been suggested that formin-like protein 1 (FMNL1) plays an important role in the pathogenic process of several hematopoietic malignancies. In this study, we performed a series of in vivo and in vitro assays to elucidate the biological functions of FMNL1 and underlying mechanisms in human nasopharyngeal carcinoma (NPC) pathogenesis. Herein, we report that high expression of FMNL1 in NPC is positively associated with an aggressive disease and/or poor patient survival. Ectopic overexpression of FMNL1 in NPC cells substantially promoted cell invadopodia formation, epithelial-mesenchymal transition (EMT) and invasiveness, whereas depletion of FMNL1 potently suppressed NPC cells invadopodia formation, EMT, and invasive/metastatic capacities. We further show that FMNL1 could enhance NPC cell aggressiveness by increasing a key downstream target, the metastasis-associated protein 1 (MTA1) gene. Importantly, ectopic overexpression of FMNL1 in NPC cells markedly improved the binding of HDAC1 with Profilin2 in the cytoplasm and suppressed the enrichment of HDAC1 on the promoter of MTA1 and thereby, leading to an increased MTA1 transcription and expression. Furthermore, in addition to the amplification of FMNL1 gene, decreased level of miR-16 in NPCs is another critical mechanism to upregulate FMNL1 expression. These results, collectively, provide first-line of evidences that high expression of FMNL1, resulted from decreased miR-16 and/or MTA1 amplification, has a potent oncogenic role to drive the development and aggressive process of NPC by upregulating MTA1, and FMNL1 might be employed as a new prognostic biomarker and therapeutic target for human NPC.

Histone deacetylase inhibitors (HDACi) had emerged as promising drugs in leukaemia, but their toxicity due to lack of specificity limited their use. Therefore, there is a need to elucidate the role of HDACs in specific settings. The study of HDAC expression in childhood leukaemia could help to choose more specific HDACi for selected candidates in a personalized approach. We analysed HDAC1-11, SIRT1, SIRT7, MEF2C and MEF2D mRNA expression in 211 paediatric patients diagnosed with acute leukaemia. There was a global overexpression of HDACs, while specific HDACs correlated with clinical and biological features, and some even predicted outcome. Thus, some HDAC and MEF2C profiles probably reflected the lineage and the maturation of the blasts and some profiles identified specific oncogenic pathways active in the leukaemic cells. Specifically, we identified a distinctive signature for patients with KMT2A (MLL) rearrangement, with high HDAC9 and MEF2D expression, regardless of age, KMT2A partner and lineage. Moreover, we observed an adverse prognostic value of HDAC9 overexpression, regardless of KMT2A rearrangement. Our results provide useful knowledge on the complex picture of HDAC expression in childhood leukaemia and support the directed use of specific HDACi to selected paediatric patients with acute leukaemia.

Current therapies for pancreatic ductal cancer (PDAC) do not sufficiently control distant metastasis. Thus, new therapeutic targets are urgently needed. Numerous studies have suggested that the epithelial-mesenchymal transition (EMT) is pivotal for metastasis of carcinomas. The fact that the EMT is reversible suggests the possibility that it is induced by an epigenetic mechanism. In this study, we aimed to investigate the role of histone deacetylase 1 (HDAC1), which is an epigenetic mechanism on distant metastasis of PDAC. We investigated the HDAC1 expression in 103 resected PDAC specimens obtained from patients who were treated with/without preoperative therapy using immunohistochemistry. To validate the findings in the clinical samples, we evaluated the HDAC1 activity, the EMT-associated genes and the migration/invasion ability in vitro, and performed an HDAC1 inhibitor assay. The high expression of HDAC1 in clinical samples was significantly associated with poor progression-free survival, especially distant metastasis-free survival. In vitro, HDAC1 inhibitors decreased the invasion ability and reversed the EMT change; the only factor to show a concomitant decrease was the expression of SNAIL. We confirmed that the HDAC1 expression was associated with the SNAIL expression in clinical samples. Moreover, the resistant cells and parental cells did not show any significant differences in the expression of HDAC1; this was consistent with the finding that preoperative therapy did not alter the HDAC1 expression in clinical samples. The targeting of HDAC1, which could suppress metastasis by inhibiting the EMT, is a promising treatment option for PDAC.

Formononetin is a bioactive non-steroidal polyphenol found in a variety of plants. In this study we evaluated the effects of formononetin on neuroinflammation in LPS-stimulated BV2 microglia. Results showed that formononetin significantly reduced the production of TNF-α, IL-6 and IL-1β, nitrite and PGE

The ligands L

Histone deacetylase 1 (HDAC1) plays a crucial role in cancer progression and development. This enzyme has been confirmed to be a key regulator of tumor biology functions, such as tumor cell proliferation, migration and invasion. However, HDAC1 expression in glioma remains controversial, and its specific function and molecular mechanism in glioblastoma is poorly understood. In this study, our findings demonstrated that protein and mRNA levels of HDAC1 were increased in glioma cell lines and glioma tissues compared to normal glial cell lines and non-neoplastic brain tissues, respectively. Furthermore, HDAC1 knockdown cells displayed decreased proliferation and invasion capabilities, whereas HDAC1 overexpressing glioblastoma cells displayed more proliferation and invasion capabilities in vitro. These novel outcomes suggested that knockdown of HDAC1 possibly suppressed the expression of phosphorylated AKT (p-AKT) and phosphorylated ERK (p-ERK) proteins, while overexpression of HDAC1 significantly increased p-AKT and p-ERK protein in glioblastoma cells. In addition, knockdown of HDAC1 repressed subcutaneous tumor growth in vivo, and led to down-regulation of p-AKT and p-ERK protein in U87 MG xenograft tumors. For the first time, we have demonstrated that HDAC1 promotes proliferation and invasion in glioblastoma cells by activating PI3K/AKT and MEK/ERK signaling pathways in vitro and in vivo. These results suggest that HDAC1 may be a novel biomarker and potential therapeutic target in glioblastoma.

T-cell acute lymphoblastic leukaemia (T-ALL) is a hematological malignancy caused by the accumulation of genomic lesions that affect the development of T-cells. ZEB1, a member of zinc finger-homeodomain family transcription factor, exhibits crucial function in promoting T-cell differentiation and potentially acts as a tumor suppressor in T-ALL. However, the molecular mechanism by which ZEB1 regulates T-ALL leukaemogenesis remains obscure. Here, we showed that oncogenic LIM only 2 (LMO2) could recruit Sap18 and HDAC1 to assemble an epigenetic regulatory complex, thus inducing histone deacetylation in ZEB1 promoter and chromatin remodeling to achieve transcriptional repression. Furthermore, downregulation of ZEB1 by LMO2 complex results in an increased leukaemia stem cell (LSC) phenotype as well as unsensitivity in response to methotrexate (MTX) chemotherapy in T-ALL cells. Importantly, we demonstrated that Trichostatin A (TSA, a HDAC inhibitor) addition significantly attenuates MTX unsensitivity caused by dysfunction of LMO2/ZEB1 signaling. In conclusion, these findings have identified a molecular mechanism underlying LMO2/ZEB1-mediated leukaemogenesis, paving a way for treating T-ALL with a new strategy of epigenetic inhibitors.

BACKGROUND: Wnt signaling plays an essential role in tumor cell growth, including the development of malignant mesothelioma (MM). Epigenetic silencing of negative Wnt regulators leading to constitutive Wnt signaling has been observed in various cancers and warrants further attention. We have reported that a succinate ether derivative of α-tocotrienol (T3E) has potent cytotoxic effects in MM cells. Thus, in this study, we investigated whether the anti-MM effect of T3E could be mediated via the epigenetic alteration of the Wnt antagonist gene, Dickkopf-1 (DKK1).
METHODS: WST-1 and cell analyzers were employed to analyze the effects of T3E on cell viability and apoptosis of human MM cell lines (H2452, H28). Real-time PCR and Western blot were performed to evaluate the expression at mRNA and protein levels. Methylation status and epigenetic modifications of DKK1's promoter regions after T3E treatment in MM cells were studied using methylation-specific PCR and Chromatin immunoprecipitation. Small interfering RNA-mediated knockdown -(siRNA), and specific inhibitors, were used to validate DKK1 as a target of T3E.
RESULTS: T3E markedly impaired MM cell viability, increased the expression of phosphorylated-JNK and DKK1 and suppressed cyclin D, a downstream target gene of Wnt signaling. Knockdown of DKK1 expression by siRNA or a specific JNK inhibitor confirmed the contribution of DKK1 and JNK to T3E-induced cytotoxicity in MM cells. On the other hand, cytoskeleton-associated protein 4 (CKAP4) expression, which promotes cell proliferation as a Wnt-independent DKK1 receptor was inhibited by T3E. Silencing CKAP4 by -siRNA did not appear to directly affect MM cell viability, thereby indicating that expression of both DKK1 and CKAP4 is required. Furthermore, T3E-mediated inhibition of both DNA methyltransferases (DNMT1, 3A, and 3B) and histone deacetylases (HDAC1, 2, 3, and 8) in MM cells leads to increased DKK1 expression, thereby promoting tumor growth inhibition. MM cells treated with Zebularine (a DNMT inhibitor) and sodium butyrate (an HDAC inhibitor) exhibited cytotoxic effects, which may explain the inhibitory action of T3E on MM cells. In addition, an enhanced expression of DKK1 in MM cells following T3E treatment is positively correlated with the methylation status of its promoter; T3E decreased DNA methylation and increased histone acetylation. Moreover, T3E specifically increased histone H3 lysine 4 (H3K4) methylation activity, whereas no effects were observed on histone H3K9 and H3K27.
CONCLUSIONS: Targeting the epigenetic induction of DKK1 may lead to effective treatment of MM, and T3E has great potential to induce anti-MM activity.

Tumors accumulate high levels of mutant p53 (mutp53), which contributes to mutp53 gain-of-function properties. The mechanisms that underlie such excessive accumulation are not fully understood. To discover regulators of mutp53 protein accumulation, we performed a large-scale RNA interference screen in a Burkitt lymphoma cell line model. We identified transformation/transcription domain-associated protein (TRRAP), a constituent of several histone acetyltransferase complexes, as a critical positive regulator of both mutp53 and wild-type p53 levels. TRRAP silencing attenuated p53 accumulation in lymphoma and colon cancer models, whereas TRRAP overexpression increased mutp53 levels, suggesting a role for TRRAP across cancer entities and p53 mutations. Through clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 screening, we identified a 109-amino-acid region in the N-terminal HEAT repeat region of TRRAP that was crucial for mutp53 stabilization and cell proliferation. Mass spectrometric analysis of the mutp53 interactome indicated that TRRAP silencing caused degradation of mutp53 via the MDM2-proteasome axis. This suggests that TRRAP is vital for maintaining mutp53 levels by shielding it against the natural p53 degradation machinery. To identify drugs that alleviated p53 accumulation similarly to TRRAP silencing, we performed a small-molecule drug screen and found that inhibition of histone deacetylases (HDACs), specifically HDAC1/2/3, decreased p53 levels to a comparable extent. In summary, here we identify TRRAP as a key regulator of p53 levels and link acetylation-modifying complexes to p53 protein stability. Our findings may provide clues for therapeutic targeting of mutp53 in lymphoma and other cancers.

Several studies have revealed that endosomal sorting controls the steady-state levels of Notch at the cell surface in normal cells and prevents its inappropriate activation in the absence of ligands. However, whether this highly dynamic physiologic process can be exploited to counteract dysregulated Notch signaling in cancer cells remains unknown. T-ALL is a malignancy characterized by aberrant Notch signaling, sustained by activating mutations in Notch1 as well as overexpression of Notch3, a Notch paralog physiologically subjected to lysosome-dependent degradation in human cancer cells. Here we show that treatment with the pan-HDAC inhibitor Trichostatin A (TSA) strongly decreases Notch3 full-length protein levels in T-ALL cell lines and primary human T-ALL cells xenografted in mice without substantially reducing NOTCH3 mRNA levels. Moreover, TSA markedly reduced the levels of Notch target genes, including pTα, CR2, and DTX-1, and induced apoptosis of T-ALL cells. We further observed that Notch3 was post-translationally regulated following TSA treatment, with reduced Notch3 surface levels and increased accumulation of Notch3 protein in the lysosomal compartment. Surface Notch3 levels were rescued by inhibition of dynein with ciliobrevin D. Pharmacologic studies with HDAC1, 6, and 8-specific inhibitors disclosed that these effects were largely due to inhibition of HDAC6 in T-ALL cells. HDAC6 silencing by specific shRNA was followed by reduced Notch3 expression and increased apoptosis of T-ALL cells. Finally, HDAC6 silencing impaired leukemia outgrowth in mice, associated with reduction of Notch3 full-length protein in vivo. These results connect HDAC6 activity to regulation of total and surface Notch3 levels and suggest HDAC6 as a potential novel therapeutic target to lower Notch signaling in T-ALL and other Notch3-addicted tumors.

PURPOSE: The aim of this study is to investigate the inhibition of cancer growth by pterostilbene through Metastasis-Associated Protein 1 (MTA1) and the histone deacetylase 1 (HDAC1) complex in hepatocellular carcinoma (HCC).
METHODS: We investigate the antitumor effects of pterostilbene (PTER) in HCC. The SMMC-7721 hepatoma cell line was cultured and treated with PTER for different time depending on the experiment. After treatment, we tested the cellular expression of proteins by Western blot and the expression of MTA1 mRNA by real-time PCR. And the immunoprecipitation was performed to confirm the acetylation in PTEN. Animal models have been established to confirm the anti-cancer effects of PTER.
RESULTS: PTER treatment could downregulate the expression of MTA1, and HDAC1 and elevates the Ac-PTEN ratio in tumors. The results suggest that PTER can decrease the expression of MTA1 and destabilize the MTA1/HDAC1 complex allowing acetylation/activation of PTEN on Lys
CONCLUSION: We demonstrated that PTER suppressed the growth, and invasion of HCC and was effective in regulating the levels of the MTA1/HDAC1/NuRD complex, promoting PTEN acetylation and apoptosis in HCC. Our findings suggest that the novel epigenetic nature of PTER anticancer activity opens up new avenues for primary chemoprevention, as well as anticancer and antimetastatic treatment.