Down-regulation of histone deacetylase 7 reduces biological activities of retinal microvascular endothelial cells under high glucose condition and related mechanism

AIM:To investigate the expression and effect of histone deacetylase 7(HDAC7)in human retinal microvascular endothelial cells(HRMECs)under high glucose condition and related mechanism,and the expression of HDAC7 in the retinal tissue in diabetic rats.METHODS:The expression of HDAC7 in HRMECs under high glucose and the retinal tissue from normal or diabetic rats were detected with immunohistochemistry and Western blot.LV-shHDAC7 HRMECs were used to study the effect of HDAC7 on cell activities.Cell count kit-8(CCK-8),5-ethynyl2’-deoxyuridine(EdU),flow cytometry,scratch test,Transwell test and tube formation assay were used to examine the ability of cell proliferation,migration,and angiogenesis.Finally,a preliminary exploration of its mechanism was performed by Western blot.RESULTS:The expression of HDAC7 was both upregulated in retinal tissues of diabetic rats and high glucosetreated HRMECs.Down-regulation of HDAC7 expression significantly reduced the ability of proliferation,migration,and tube formation,and reversed the high glucose-induced high expression of CDK1/Cyclin B1 and vascular endothelial growth factor in high glucose-treated HRMECs.CONCLUSION:High glucose can up-regulate the expression of HDAC7 in HRMECs.Down-regulation of HDAC7 can inhibit HRMECs activities.HDAC7 is proposed to be involved in pathogenesis of diabetic retinopathy and a therapeutic target.

Current evidence for histone deacetylase inhibitors in pancreatic cancer

Pancreatic cancer is one of the most aggressive human cancers,with more than 200 000 deaths worldwide every year.Despite recent efforts,conventional treatment approaches,such as surgery and classic chemotherapy,have only slightly improved patient outcomes.More effective and well-tolerated therapies are required to reverse the current poor prognosis of this type of neoplasm.Among new agents,histone deacetylase inhibitors (HDACIs) are now being tested.HDACIs have multiple biological effects related to acetylation of histones and many non-histone proteins that are involved in regulation of gene expression,apoptosis,cell cycle progression and angiogenesis.HDACIs induce cell cycle arrest and can activate the extrinsic and intrinsic pathways of apoptosis in different cancer cell lines.In the present review,the main mechanisms by which HDACIs act in pancreatic cancer cells in vitro,as well as their antiproliferative effects in animal models are presented.HDACIs constitute a promising treatment for pancreatic cancer with encouraging anti-tumor ef-fects,at well-tolerated doses.

Histone deacetylase inhibitors and pancreatic cancer:Are there any promising clinical trials?

Pancreatic cancer,although not very frequent,has an exceptionally high mortality rate,making it one of the most common causes of cancer mortality in developed countries.Pancreatic cancer is difficult to diagnose,allowing few patients to have the necessary treatment at a relatively early stage.Despite a marginal benefit in survival,the overall response of pancreatic cancer to current systemic therapy continues to be poor,and new therapies are desperately needed.Histone deacetylase(HDAC) enzymes play an important role in the development and progression of cancer and HDAC inhibitors(HDACIs) have been shown to induce differentiation and cell cycle arrest,activate the extrinsic or intrinsic pathways of apoptosis,and inhibit invasion,migration and angiogenesis in different cancer cell lines.As a result of promising preclinical data,various HDACIs are being tested as either monotherapeutic agents or in combination regimens for both solid and hematological malignancies.Vorinostat was the first HDACI approved by the Food and Drug Administration for patients with cutaneous T-cell lymphoma.The use of HDACIs in clinical trials,in pretreated and relapsed patients suffering from advanced pancreatic cancer is discussed.Unfortunately,clinical data for HDACIs in patients with pancreatic cancer are inadequate,because only a few studies have included patients suffering from this type of neoplasm and the number of pancreatic cancer patients that entered HDACIs phase Ⅱ/Ⅲ trials,among others with advanced solid tumors,is very limited.More studies recruiting patients with pancreatic cancer remain to determine the efficiency of these therapies.

Alpha-tubulin deacetylase as a potential and novel target for the prevention of Parkinson's disease progression

Parkinson＇s disease （PD） is the second most common neurodegenerative disorder and is characterized by its progressive course. The current therapies are aimed at alleviating symptoms by rescuing the unbalanced physiological dopamine metabolism and recovery of damaged neuronal circuits. However, these strategies result in insufficient clinical benefits for many patients and fail to halt disease progression. Therefore, new therapeutic targets could serve as the gateway against PD degeneration. One pathological hallmark of PD is the formation of intracytoplasmic protein inclusions or Lewy bodies, in neurons. Recent studies have suggested that Lewy bodies are formed similarly to aggresomes, and results have supported the concept that the novel cellular organelle, the aggresome, is a cytoprotective response that sequesters and facilitates clearance of potentially toxic protein aggregates. In addition, a-tubulin deacetylase has been shown to regulate aggresome formation and rescue neural cell viability in response to misfolded protein. Therefore, the regulation of aggresome formation to trigger cellular self-protection system could arrest PD progression. The present study discusses research progress related to Lewy bodies, aggresomes, and histone deacetylases, with an emphasis on histone deacetylase 6 and sirtuin type 2.

Deacetylase inhibitors-focus on non-histone targets and effects

Inhibitors of protein deacetylases have recently been established as a novel therapeutic principle for several human diseases,including cancer.The original notion of the mechanism of action of these compounds focused on the epigenetic control of transcriptional processes, especially of tumor suppressor genes,by interfering with the acetylation status of nuclear histone proteins,hence the name histone deacetylase inhibitors was coined.Yet,this view could not explain the high specificity for tumor cells and recent evidence now suggests that non-histone proteins represent major targets for protein deacetylase inhibitors and that the post-translational modification of the acetylome is involved in various cellular processes of differentiation,survival and cell death induction.

Neuroprotective mechanism of TMP269, a selective class ⅡA histone deacetylase inhibitor, after cerebral ischemia/reperfusion injury

TMP269 is a selective class ⅡA histone deacetylase inhibitor that has a protective effect on the central nervous system, whose specific mechanism of action is unclear. We aimed to reveal the optimal concentration of TMP269 for protecting against cerebral ischemia/reperfusion injury and its neuroprotective mechanism. Male Sprague-Dawley rats were randomly divided into sham, ischemia/reperfusion, and 1, 4, 10 and 16 mg/kg TMP269 groups. Cerebral ischemia/reperfusion injury was induced by middle cerebral artery occlusion. TMP269 was intraperitoneally administered at different doses 0.5 hours before ischemia induction. Western blot assay and immunohistochemistry were used to detect effects of TMP269 on histone 2 acetylation. The results showed that the level of histone 2 acetylation was increased 24 hours after TMP269 injection. 2,3,5-Triphenyltetrazolium chloride staining was utilized to examine effect of TMP269 on infarct volume. The results found that different doses of TMP269 could reduce the infarct volume. Western blot assay, immunohistochemistry and Evans blue staining were employed to measure the effect of TMP269 on blood-brain barrier. The results showed that TMP269 counteracted the abnormal endothelial cell permeability changes caused by cerebral ischemia/reperfusion. Western blot assay and immunohistochemistry were used to determine the effect of TMP269 on tissue kallikrein. The results found that TMP269 up-regulated the expression of tissue kallikrein. Western blot assay further determined the optimal concentration to be 4 mg/kg. In conclusion, TMP269 plays a neuroprotective role by up-regulating the level of histone 2 acetylation, alleviating endothelial cell injury after cerebral ischemia/reperfusion, and up-regulating the expression of tissue kallikrein. The experimental protocol was approved in 2014 by the Department of Laboratory Animal Science, Fudan University, China(approval No. 20140143 C001).

lncRNA-SNHG15 accelerates the development of hepatocellular carcinoma by targeting mi R-490-3p/histone deacetylase 2 axis

BACKGROUND Hepatocellular carcinoma(HCC)has become a great threat for people’s health.Many long noncoding RNAs are involved in the pathogenesis of HCC.SNHG15,as a tissue specific long noncoding RNAs,has been studied in many human cancers,except HCC.AIM To explore the regulatory mechanism of SNHG15 in HCC.METHODS In the present research,101 HCC patient samples,two HCC cell lines and one normal liver cell line were used.RT-qPCR and Western blot analysis were applied to detect SNHG15,miR-490-3p and histone deacetylase 2(HDAC2)expression.The regulatory mechanism of SNHG15 was investigated using CCK-8,Transwell and luciferase reporter assays.RESULTS Our research showed that up-regulation of SNHG15 was found in HCC and was related to aggressive behaviors in HCC patients.Moreover,knockdown of SNHG15 restrained HCC cell proliferation,migration and invasion.In addition,SNHG15 served as a molecular sponge for miR-490-3p.Further,miR-490-3p directly targets HDAC2.HDAC2 was involved in HCC progression by interacting with the SNHG15/miR-490-3p axis.CONCLUSION In conclusion,long noncoding RNA SNHG15 promotes HCC progression by mediating the miR-490-3p/HDAC2 axis in HCC.

Inhibition of histone deacetylase 2 mitigates profibrotic TGF-β1 responses in fibroblasts derived from Peyronie＇s plaque

Epigenetic modifications, such as histone acetylation/deacetylation, have been shown to play a role in the pathogenesis of fibrotic disease. Peyronie＇s disease （PD） is a localized fibrotic process of the tunica albuginea, which leads to penile deformity. This study was undertaken to determine the anti-fibrotic effect of small interfering RNA （siRNA）-mediated silencing of histone deacetylase 2 （HDAC2） in primary fibroblasts derived from human PD plaque. PD fibroblasts were pre-treated with HDAC2 siRNA and then stimulated with transforming growth factor-p1 （TGF-β1）. Protein was extracted from treated fibroblasts for Western blotting and the membranes were probed with antibody to phospho-Smad2/Smad2, phospho-Smad3/Smad3, smooth muscle α-actin and extracellular matrix proteins, including plasminogen activator inhibitor-β 1, fibronectin, collagen I and collagen IV. We also performed immunocytochemistry to detect the expression of extracellular matrix proteins and to examine the effect of HDAC2 siRNA on the TGF-β1-induced nuclear translocation of Smad2/3 in fibroblasts. Knockdown of HDAC2 in PD fibroblasts abrogated TGF-β1-induced extracellular matrix production by blocking TGF-β1-induced phosphorylation and nuclear translocation of Smad2 and Smad3, and by inhibiting TGF-β1-induced transdifferentiation of fibroblasts into myofibroblasts. Decoding the individual function of the HDAC isoforms by use of siRNA technology, preferably siRNA for HDAC2, may lead to the development of specific and safe epigenetic therapies for PD.

Drug repurposing of histone deacetylase inhibitors that alleviate neutrophilic inflammation in acute lung injury and idiopathic pulmonary fibrosis via inhibiting leukotriene a4 hydrolase and blocking LTB4 biosynthesis

OBJECTIVE Leukotriene B4(LTB4)biosynthesis and subsequently neutrophilic inflammation may provide a potential strategy for the treatment of acute lung injury(ALI)or idiopathic pulmonary fibrosis(IPF).To provide a potential strategy for the treatment of ALI or IPF,we identified potent inhibitors of Leukotriene A4 hydrolase(LTA4H),a key enzyme in the biosynthesis of LTB4.METHODS In this study,we identified two known histone deacetylase(HDAC)inhibitors,suberanilohydroxamic acid(SAHA)and its analogue 4-(dimethylamino)-N-[7-(hydroxyamino)-7-oxoheptyl]benzamide(M344),as effective inhibitors of LTA4H using enzymatic assay,thermofluor assay,and X-ray crystallographic investigation.We next tested the effect of SAHA and M344 on endogenous LTB4 biosynthesis in neutrophils by ELISA and neutrophil migration by transwell migration assay.A murine experimental model of ALI was induced by lipopolysaccharide(LPS)inhalation.Histopathological analysis of lung tissue using H&E staining revealed the serious pulmonary damage caused by LPS treatment and the effect of the SAHA.We next examined m RNA and protein levels of pro-inflammatory cytokines in lung tissue and bronchoalveolar lavage fluid using q RT-PCR and ELISA to further investigate the underlying mechanisms of anti-inflammatory activities by SAHA.We also investigated the effects of SAHA and M344 on a murine experimental model of bleomycin(BLM)-induced IPF model.RESULTS The results of enzymatic assay and X-ray crystallography showed that both SAHA and M344 bind to LTA4H,significantly decrease LTB4 levels in neutrophil,and markedly diminish early neutrophilic inflammation in mouse models of ALI and IPF under a clinical safety dose.CONCLUSION Collectively,SAHA and M344 would provide promising agents with well-known clinical safety for potential treatment in patients with ALI and IPF via pharmacologically inhibiting LAT4H and blocking LTB4 biosynthesis.

QSAR Studies on the Inhibitory Activityof Levofloxacin-thiadiazole HDACi Conjugates to Histone Deacetylases

A molecular electronegativity distance vector(M)based on 13 atomic types has been used to describe the structures of 19 conjugates(LHCc)of levofloxacin-thiadiazole HDAC inhibitor(HDACi)and related inhibitory activities(pH,i=1,2,6)of LHCc against histone deacetylases(HDACs,such as HDAC1,HDAC2 and HDAC6).The quantitative structure-activity relationships(QSAR)were established by using leaps-and-bounds regression analysis for the inhibitory activities(pH)of 19 above compounds to HDAC1,HDAC2 and HDAC6 along with M.The correlation coefficients(R~2)and the leave-one-out(LOO)cross validation Rfor the pH,pHand pHmodels were 0.976 and 0.949;0.985 and 0.977;0.976 and 0.932,respectively.The QSAR models had favorable correlations,as well as robustness and good prediction capability by R~2,F,R~2,A,Fand Vtests.Validated by using 3876 training sets,the models have good external prediction ability.The results indicate that the molecular structural units:–CH–(g=1,2),–NH,–OH,=O,–O–and–S–are the main factors which can affect the inhibitory activity of pH,pHas well as pHbioactivities of these compounds directly.Accordingly,the main interactions between HDACs inhibitor and HDACs are hydrophobic interaction,hydrogen bond,and coordination with Znto form compounds,which is consistent with the results in reports.

Histone deacetylase inhibitor pre-treatment enhances the efficacy of DNA-interacting chemotherapeutic drugs in gastric cancer

BACKGROUND The prognosis of gastric cancer continues to remain poor,and epigenetic drugs like histone deacetylase inhibitors(HDACi)have been envisaged as potential therapeutic agents.Nevertheless,clinical trials are facing issues with toxicity and efficacy against solid tumors,which may be partly due to the lack of patient stratification for effective treatments.To study the need of patient stratification before HDACi treatment,and the efficacy of pre-treatment of HDACi as a chemotherapeutic drug sensitizer.METHODS The expression activity of class 1 HDACs and histone acetylation was examined in human gastric cancer cells and tissues.The potential combinatorial regime of HDACi and chemotherapy drugs was defined on the basis of observed drug binding assays,chromatin remodeling and cell death.RESULTS In the present study,the data suggest that the differential increase in HDAC activity and the expression of class 1 HDACs are associated with hypoacetylation of histone proteins in tumors compared to normal adjacent mucosa tissue samples of gastric cancer.The data highlights for the first time that pretreatment of HDACi results in an increased amount of DNA-bound drugs associated with enhanced histone acetylation,chromatin relaxation and cell cycle arrest.Fraction-affected plots and combination index-based analysis show that pre-HDACi chemo drug combinatorial regimes,including valproic acid with cisplatin or oxaliplatin and trichostatin A with epirubicin,exhibit synergism with maximum cytotoxic potential due to higher cell death at low combined doses in gastric cancer cell lines.CONCLUSION Expression or activity of class 1 HDACs among gastric cancer patients present an effective approach for patient stratification.Furthermore,HDACi therapy in pretreatment regimes is more effective with chemotherapy drugs,and may aid in predicting individual patient prognosis.

Correlation between Histone Deacetylase 9 and Regulatory T Cell in Patients with Chronic Heart Failure

Heart failure （HF） is the end stage of various kinds of cardiovascular diseases and leads to a high mortality worldwide. Numerous studies have demonstrated that frequencies of CD4＋CD25＋Foxp3＋ regulatory T cells （Tregs） are reduced in HF patients and properly expanding Tregs attenuates HF progression. Histone deacetylase （HDAC） 9 has been revealed to contribute to several cardiovascular and cerebrovascular diseases. Plenty of studies showed that HDAC9 negatively regulated the number and function of Tregs. Thus, we aim to investigate the expression of HDAC 9 in patients with chronic heart failure （CHF） and the relationship among HDAC9, Tregs and CHF. Our research showed a reduced number of Tregs and an increased expression of HDAC9 mRNA in CHF patients. Patients with CHF were divided into two groups by heart function grade of New York Heart Association （NYHA）, we found that the HDAC9 mRNA expression level in NYHA grade Ⅱ -Ⅲ group were lower than that in NYHA grade IV group. More importantly, the correlation study suggested that the expression of HDAC9 mRNA was negatively correlated to Tregs frequency and left ventricular ejection fraction （LVEF）, whereas positively correlated to larger left ventricular end-diastolic dimension （LVEDD） and B-type natriuretic peptide （BNP） in patients with CHF. The correlation studies also showed a positive correlation between HDAC9 and the severity of CHF. Our research suggests that HDAC9 may be a new indicator for assessing CHF and it may offer a new direction for research of CHF.

Histone deacetylases and cardiovascular cell lineage commitment

Cardiovascular diseases(CVDs), which include alldiseases of the heart and circulation system, are the leading cause of deaths on the globally. During the development of CVDs, choric inflammatory, lipid metabolism disorder and endothelial dysfunction are widely recognized risk factors. Recently, the new treatment for CVDs that designed to regenerate the damaged myocardium and injured vascular endothelium and improve recovery by the use of stem cells, attracts more and more public attention. Histone deacetylases(HDACs) are a family of enzymes that remove acetyl groups from lysine residues of histone proteins allowing the histones to wrap the DNA more tightly and commonly known as epigenetic regulators of gene transcription. HDACs play indispensable roles in nearly all biological processes, such as transcriptional regulation, cell cycle progression and developmental events, and have originally shown to be involved in cancer and neurological diseases. HDACs are also found to play crucial roles in cardiovascular diseases by modulating vascular cell homeostasis(e.g., proliferation, migration, and apoptosis of both ECs and SMCs). This review focuses on the roles of different members of HDACs and HDAC inhibitor on stem cell/ progenitor cell differentiation toward vascular cell lineages(endothelial cells, smooth muscle cells and Cardiomyocytes) and its potential therapeutics.

Histone deacetylases,microRNA and leptin crosstalk in pancreatic cancer

Because pancreatic cancer(PC) historically has had poor prognosis and five year survival rates,it has been intensely investigated.Analysis of PC incidence and biology has shown a link between different risk factors such as smoking,alcoholism,and obesity and disease progression.Important factors affecting PC include the epigenomic changes driven by DNA methylation and histone acetylation,and actions of microRNA inducing oncogenic or tumor suppressor effects.Studies have identified markers whose dysregulation seem to play important roles in PC progression.PC markers involve classical histone deacetylases(HDAC),PC stem cell(PCSC),and leptin.In this review,we discuss the role of several PC biomarkers,and the potential crosstalk between HDAC,microRNA,and leptin in PC progression.Dysregulated expression of these molecules can increase proliferation,survival,PCSC,resistance to chemotherapy and tumor angiogenesis.The potential relationships between these molecules are further analyzed using data from The Cancer Genome Atlas and crosstalk pathways generated by the Pathway Studio Platform(Ariadne Genomics,Inc.).Oncogenic miRNA21 and tumor suppressor miRNA200 have been previously linked to leptin signaling.Preliminary analysis of PC biopsies and signaling crosstalk suggests that the main adipokine leptin could affect the expression of microRNA and HDAC in PC.Data analysis suggests that HDAC-microRNA-leptin signaling crosstalk may be a new target for PC therapy.

Molecular Cloning and Phylogenetic Analysis of a Chitin Deacetylase Isolated from the Epidermis of the Red Snow Crab <i>Chionoecetes japonicas</i>

Chitin deacetylase (CDA;EC 3. 5. 1. 41) catalyzes the deacetylation of chitin. In this study, we successfully cloned and sequenced a chitin deacetylase gene from the red snow crab Chionoecetes japonicas. By using reverse transcription-polymerase chain reaction (RT-PCR) and 5' and 3' rapid amplification of cDNA ends, we obtained a 2141-bp amplicon containing a chitin deacetylase gene (CjCDA) from the epidermis of C. japonicas. The amplicon contains a 1575-bp open reading frame that is predicted to encode a 525-amino acid protein. The structure predicted from the deduced amino acid sequence included an N-terminal signal peptide, chitin-binding domain (CBD), low-density lipoprotein receptor class A domain (LDL-A), and catalytic domain. Comparative analysis of the deduced amino acid sequence of CjCDA revealed the highest homology (74%) to gastrolith protein 59 of Cherax quadricarinatus. We used RT-PCR to evaluate the expression of CjCDA in various tissues of C. japonicas, and we observed that CjCDA was expressed only in the epidermis. A phylogenetic analysis, using the amino acid sequences of CjCDA and other known chitin deacetylases, showed that CjCDA belonged to a group of crustacean chitin deacetylases. To our knowledge, this is the first study reporting the cDNA cloning of a chitin deacetylase from a crab.

Histone deacetylase 6 mediated NALP3 inflammasome activation contributes to dopaminergic injury in experimental models of Parkinson disease

OBJECTIVE To investigate the mechanisms of histone deacetylase 6(HDAC6)deacetylation activity on NALP3 inflammasome activation and explore the protective effect s of pharmacological inhibition of HDAC6 on dopaminergic injury.METHODS In vitro and in vivo6-OHDA induced Parkinson disease(PD) model was used.To distinguish the effect of deacetylase catalytic domains of HDAC6,we used a specific HDAC6 inhibitor tubastatin A(TBA),siRNAHDAC6,and pcDNA-HDAC6-FLAG plasmid.First,the role of pharmacological inhibition or siRNA or overexpression of HDAC6 on NALP3 inflammasome and cell death was explored by using Western blotting,TUNEL,and flow cytometric analysis.Then,the acetylation level of peroxiredoxin 2(Prx2) and the production of reactive oxygen species(ROS) in cells under different treatments was examined by using immunoprecipitation and DCFH-DA fluorescence assay.The effects of TBA on neuroinflammation and nigrostriatal dopaminergic system in vivo was further investigated by using Western blotting,immunohistochemistry and HPLC analysis.RESULTS TBA remarkably inhibited 6-OHDA induced NALP3 inflammasome activation,reduced dopaminergic neurodegeneration and neuroinflammation as demonstrated by increased TH-positive neurons,striatal levels of DA and its metabolites,and decreased gliocyte proliferation.TBA recovered acetylation of Prx2,and reduced ROS production,which was associated with decreased NALP3 inflammasome activation.CONCLUSION HDAC6 may medicate deacetylation of Prx2 contributes to NALP3 inflammasome activation in PD pathology,suggesting that the development of specific pharmacological inhibitors of HDAC6 be required for this kind of disease.

Histone deacetylases in hearing loss: Current perspectives for therapy

Hearing loss is one of the most frequent health issues in industrialized countries. The pathogenesis and molecular mechanisms of hearing loss are still unclear. Histone deacetylases(HDACs) are emerging as key enzymes in many physiological processes, including chromatin remodeling,regulation of transcription, DNA repair, metabolism, genome stability and protein secretion. Recent studies indicated that HDACs are associated with the development and progression of hearing loss. Dysfunction of HDACs could promote the oxidative stress and aging in the inner ear. In light of considering the current stagnation in the development of therapeutic options, the need for new strategies in the treatment of hearing loss has never been so pressing. In this review, we will summarize the reported literatures for HDACs in hearing loss and discuss how HDAC family members show different performances for the possibility of process of diseases development. The possibility of pharmacological intervention on hearing loss opens a novel path in the treatment of hearing loss.

Peanut testa extracts enhance anticancer effect of cisplatin against human cholangiocarcinoma cells via modulation of histone deacetylase inhibitory activity

Objective:To investigate the effect of combination treatments of cisplatin and KK4 and ICG15042 peanut testa extracts against cholangiocarcinoma cells in vitro.Methods:The growth inhibition,cell cycle arrest and apoptosis of cholangiocarcinoma cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry analysis,respectively.The levels of proteins involved in apoptosis were assessed using Western blotting assays.The caspase activity was assessed using a colorimetric caspase activity assay.Results:Cisplatin and peanut(KK4 and ICG15042)testa extracts inhibited the growth of cholangiocarcinoma cell lines(KKUM214 and KKU-100 cells)in a dose-and time-dependent manner.The combination treatments reduced cell viability and induced apoptosis of cholangiocarcinoma cells more efficiently than singledrug treatments.Cancer cell death synergistically mediated by cisplatin and peanut testa extracts was observed in KKU-M214 cells(combination index<1.0)but not in KKU-100 cells(combination index>1.0).The combination treatments also increased the subG1 population and caused KKU-M214 cell cycle arrest at S and G2/M phases,which were the combined effects of cisplatin(S phase arrest)and peanut testa extracts(G2/M phase arrest).In addition,p ERK1/2,Ac-H3,Bcl-2 and proteins related to apoptosis,including Bax and caspases 3,8,9,exhibited enhanced expression in KKUM214 cells.The combination treatments caused down-regulation of p53,whereas the expression of p21 was fairly constant when compared with cisplatin single drug treatment.Conclusions:Peanut testa extracts in combination with cisplatin synergistically reduce cell viability and induce apoptosis through stimulation of caspases 3,8 and 9 in KKU-M214 cells.

Induction of Myelogenous Leukemia Cells with Histone Deacetylase Inhibitors through Down-regulating the Daxx Protein Expression

The effects of two different histone deacetylase （HDAC） inhibitors, sodium butyrate （NAB） and trichostatin A （TSA）,on apoptosis of human leukemic cells in vitro and the molecular mechanisms were investigated. The experiments were divided up 5 groups： control group, NaB group, TSA group, NaB＋Z-VAD-FMK group and TSA＋Z-VAD-FMK group. The apoptosis rate was determined by mor- phological analysis and flow cytomytry. The expression of Daxx, Bcl-2, and Bcl-xl proteins was detected by Western blot. NaB and TSA could induce the apoptosis of HL-60 and K562 cells, and Z-VAD-FMK caused a marked decrease in apoptosis induced by HDAC inhibitors. HDAC inhibitors could down-regulate the expression of Daxx protein, but had no significant influence on the expression of Bcl-2 and Bcl-xl proteins. The results suggested that NaB and TSA induce distinct caspase-dependent apoptosis of human leukemic cells through down-regulating the expression of Daxx protein in vitro.

Targeting pancreatic cancer immune evasion by inhibiting histone deacetylases

The immune system plays a vital role in maintaining the delicate balance between immune recognition and tumor development.Regardless,it is not uncommon that cancerous cells can intelligently acquire abilities to bypass the antitumor immune responses,thus allowing continuous tumor growth and development.Immune evasion has emerged as a significant factor contributing to the progression and immune resistance of pancreatic cancer.Compared with other cancers,pancreatic cancer has a tumor microenvironment that can resist most treatment modalities,including emerging immunotherapy.Sadly,the use of immunotherapy has yet to bring significant clinical breakthrough among pancreatic cancer patients,suggesting that pancreatic cancer has successfully evaded immunomodulation.In this review,we summarize the impact of genetic alteration and epigenetic modification(especially histone deacetylases,HDAC)on immune evasion in pancreatic cancer.HDAC overexpression significantly suppresses tumor suppressor genes,contributing to tumor growth and progression.We review the evidence on HDAC inhibitors in tumor eradication,improving T cells activation,restoring tumor immunogenicity,and modulating programmed death 1 interaction.We provide our perspective in targeting HDAC as a strategy to reverse immune evasion in pancreatic cancer.