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.

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.

Novel hybrids from N-hydroxyarylamide and indole ring through click chemistry as histone deacetylase inhibitors with potent antitumor activities

Novel hybrid molecules 8a-8o were designed and synthesized by connecting indole ring with N- hydroxyarylamide through alkyl substituted triazole, and their in vitro biological activities were evaluated. It was discovered that most of target compounds showed promising anticancer activities, particularly for 8n, which had a significant HDACs inhibitory and antiproliferative activities comparable to or slightly stronger than SAHA against human carcinoma cells. Furthermore, compound 8n exhibited much better selectivity for HDAC1 over HDAC6 and HDAC8 than SAHA. In addition, compound 8n also could dose-dependently induce cancer cell cycling arrest at G0/G1 phase and promote the expression of the acetylation for histone H3 and tubulin in vitro. Therefore, our novel findings may provide a new framework for the design of new selective HDAC inhibitor for the treatment of cancer.

3D-QSAR Models of Anti-tumor Activity for Histone Deacetylase Inhibitors Containing Dihydropyridin-2-one

A 3D-QSAR study was conducted to analyze the anti-tumor activity(pHs,s=1,6)of dihydropyridin-2-one containing histone deacetylase inhibitor(DHDACi)to histone deacetylase(HDACs,s=1,6)by the comparative molecular field analysis(CoMFA)method.The predicting model was established based on the training set of 22 compounds,which was verified by the test set of 6 compounds containing template molecule.The results showed that the contributions of steric and electrostatic fields to pH1 are 37.6%and 62.4%,and those to pH6 are 44.6%and 55.4%,respectively.The coefficients of the cross-validation(Rcv2)and the non cross-validation(R2)are 0.574 and 0.947 for pH1,and 0.488 and 0.884 for pH6,respectively.The models were then used to predict the activities of the compounds for the training and testing sets.The results indicated that the models had strong stability and good predictability.Based on the 3D contour maps,several new potential inhibitors with higher anti-tumor activity were designed.However,the effectiveness of these potential inhibitors is still needed to be verified by the experimental results.

Histone Deacetylase Inhibitors Romidepsin and Vorinostat Promote Hepatitis B Virus Replication by Inducing Cell Cycle Arrest

Background and Aims:Chronic hepatitis B virus(HBV)infection is a global public health challenge.HBV reactivation usually occurs in cancer patients after receiving cytotoxic chemotherapy or immunosuppressive therapies.Romidepsin(FK228)and vorinostat(SAHA)are histone deacetylase inhibitors(HDACi)approved by the Food and Drug Administration as novel antitumor agents.The aim of this study was to explore the effects and mechanisms of HDACi treatment on HBV replication.Methods:To assess these effects,human hepatoma cell lines were cultured and cell viability after FK228 or SAHA treatment was measured by the CCK-8 cell counting kit-8 assay.Then,HBV DNA and RNA were quantified by real-time PCR and Southern blotting.Furthermore,analysis by western blotting,enzyme-linked immunosorbent assay(ELISA),immunohistochemistry,and flow cytometry was performed.Results:FK228/SAHA treatment significantly promoted HBV replication and biosynthesis in both HBV-replicating cells and HBV-transgenic mouse model.Flow cytometry assay indicated that FK228/SAHA enhanced HBV replication by inducing cell cycle arrest through modulating the expression of cell cycle regulatory proteins.In addition,simultaneous inhibition of HDAC1/2 by FK228 promoted HBV replication more effectively than the broad spectrum HDAC inhibitor SAHA.Conclusions:Overall,our results demonstrate that cell cycle blockage plays an important role in FK228/SAHAenhanced HBV replication,thus providing a potential avenue for rational use of HDACi in patients with chronic hepatitis B.

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.

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.

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.

Inhibitory Effect of Histone Deacetylase Inhibitor on the Proliferation of Leukemia Cells and Its Anti-Tumor Pharmacology

The aim of this study was to explore the inhibitory effect of histone deacetylase inhibitor (HDACI) on the proliferation of leukemia cells. The two kinds of leukemia cells (human promyelocytic leukemia cell (HL-60) and human acute myelogenous leukemia cell (KG-1)) were selected for in vitro research. Besides, Chidamide, a kind of benzamide HDACI, was applied to induce and culture the HL-60 and KG-1 cells, and the anti-tumor cell proliferation activity of Chidamide on HL-60 and KG-1 was detected by the methyl thiazolyl tetrazolium (MTT) assay, which was 5.6 and 6.1 in turn. The cell scratch experiment verified that Chidamide had the metastasis inhibitory effect on HL-60 and KG-1 cells. Flow cytometry was employed to measure the percentage of apoptotic cells, and it was found that the percentage of apoptotic cells was 55.6% ± 1% and 48.6% ± 1% in sequence after HL-60 and KG-1 cells were treated with Chidamide for 36 hours. The number of auto-phagosomes was determined by transmission electron microscopy showing that the number of auto-phagosomes in HL-60 and KG-1 cells was 12 ± 1 and 10 ± 1, respectively after the induction process of Chidamide. The phosphorylated histone H2AX protein (γ-H2AX) recognition antibody immunofluorescence method was adopted to determine the deoxyribonucleic acid (DNA) damage, and the positive rates of HL-60 and KG-1 cells reached 28.41% and 26.35%, respectively after Chidamide treatment. Therefore, Chidamide, as a kind of HDACI, could effectively inhibit the proliferation of leukemia cells, so that the results of this experiment had a good guiding meaning for the clinical diagnosis and treatment of leukemia.

Synthesis,Biological Evaluation and Molecular Modeling of Cyclic Tetrapeptide Based Inhibitors HDAC

Histone deacetylases（HDACs） are considered to be among the most promising targets for the development of anti-cancer drugs,and HDAC inhibitors（HDACIs） have become a promising class of anti-cancer drugs.To explore whether thioacetyl group as the zinc binding group（ZBG） and a slight change in the hydrophobicity of the recognition domain of HDACIs could alter their activities,we synthesized a series of cyclo[-L-Am7（SAc）-Aib-L-Phe（n-Cl）D-Pro-] and evaluated their HDAC-inhibitory and antiproliferative activities.The results show that these peptides could inhibit HDAC at 10-9 mol/L level,and could selectively inhibit the proliferation of three human cancer cell lines with IC 50 at 10-6 mol/L level.Docking study was conducted to examine the mechanisms by which these peptides interact with HDAC2.It appeared that a zinc ion in the active site of HDAC was coordinated by the carbonyl oxygen atom of the ZBG in the inhibitor.Both the ZBG domain of all the peptides and the surface recognition domain of cyclo[-L-Am7（SAc）-Aib-L-Phe（o-Cl）-D-Pro-] and that of cyclo[-L-Am7（SAc）-Aib-L-Phe（m-Cl）-D-Pro-] interacted with HDAC2 via hydrogen bonding.Hydrophobic interaction has been considered to provide favorable contributions to stabilizing the complexes,and the introduction of a chlorine atom at the aromatic ring on the L-Phe position of these peptides affected the interaction between each of these inhibitors and the enzyme,resulting in slight change in the structure of the surface recognition domain of the peptides.

Entinostat,a classⅠselective histone deacetylase inhibitor,plus exemestane for Chinese patients with hormone receptor-positive advanced breast cancer:A multicenter,randomized,double-blind,placebo-controlled,phase 3 trial

Entinostat plus exemestane in hormone receptor-positive(HR+)advanced breast cancer(ABC)previously showed encouraging outcomes.This multicenter phase 3 trial evaluated the efficacy and safety of entinostat plus exemestane in Chinese patients with HR+ABC that relapsed/progressed after≥1 endocrine therapy.Patients were randomized(2:1)to oral exemestane 25 mg/day plus entinostat(n=235)or placebo(n=119)5 mg/week in 28-day cycles.The primary endpoint was the independent radiographic committee(IRC)-assessed progression-free survival(PFS).The median age was 52(range,28—75)years and 222(62.7%)patients were postmenopausal.CDK4/6 inhibitors and fulvestrant were previously used in 23(6.5%)and 92(26.0%)patients,respectively.The baseline characteristics were comparable between the entinostat and placebo groups.The median PFS was 6.32(95%CI,5.30—9.11)and 3.72(95%CI,1.91—5.49)months in the entinostat and placebo groups(HR,0.76;95%CI,0.58—0.98;P=0.046),respectively.Grade≥3 adverse events(AEs)occurred in 154(65.5%)patients in the entinostat group versus 23(19.3%)in the placebo group,and the most common grade≥3 treatment-related AEs were neutropenia[103(43.8%)],thrombocytopenia[20(8.5%)],and leucopenia[15(6.4%)].Entinostat plus exemestane significantly improved PFS compared with exemestane,with generally manageable toxicities in HR+ABC(ClinicalTrials.gov#NCT03538171).

Chidamide,Decitabine,Cytarabine,Aclarubicin,and Granulocyte Colony-stimulating Factor Therapy for Patients with Relapsed/Refractory Acute Myeloid Leukemia:A Retrospective Study from a Single-Center

Objective Preclinical evidence and clinical trials have suggested synergistic effects of epigenetic modifiers in combination with cytotoxic agents for the treatment of leukemia.However,their efficacy in patients with relapsed/refractory acute myeloid leukemia(R/R AML)remains unclear.Methods Clinical data of R/R AML patients who received a CDCAG regimen(chidamide,decitabine,cytarabine,aclarubicin,and granulocyte colony-stimulating factor)from July 1,2018 to October 31,2021 at our center were retrospectively assessed,and the safety and efficacy of the CDCAG regimen were evaluated.Patients were followed up until November 30,2021,with a median follow-up of 21.6 months(95%CI:10.0–33.2 months).Results A total of 67 patients were enrolled.Two patients died within 3 weeks after the initiation,and therefore only 65 patients underwent the assement for clinical response and survival.It was found that 56.9%patients achieved complete remission with a median overall survival(OS)of 9.6 months.The median OS of responders was 25.9 months,while that of non-responders was 5.0 months(P<0.0001).Patients with gene mutations had a superior overall response rate(ORR)(80.4%vs.45.5%,P=0.043)compared to those without gene mutations.The presence of DNA methyltransferase 3 A(DNMT3A),ten-eleven translocation-2(TET2),and isocitrate dehydrogenase 1/2(IDH1/2)mutations did not affect the response rate(88.2%vs.68.9%,P=0.220)and reflected a better OS(not attained vs.9.0 months,P=0.05).The most common non-hematologic adverse events were pulmonary infection(73.1%),followed by febrile neutropenia(23.9%)and sepsis(19.4%).Conclusions The CDCAG regimen was effective and well-tolerated in R/R AML patients,increasing the potential for allogeneic hematopoietic stem cell transplantation.Moreover,patients with DNMT3A,TET2,and IDH1/2 mutations might benefit from this regimen.

Design, Synthesis and Biological Evaluation of Novel Selective Thiol-based Histone Deacetylase（HDAC） Ⅵ Inhibitors Bearing Indeno[1,2-c]pyrazole or Benzoindazole Scaffold

A series of thiol-based mdeno[1,2-c]pyrazoles and benzoindazole compounds was designed and synthesized according to the structural specificity of his-tone deacetylase VI（HDAC6） and the structural characteristics of HDAC inhibitors. The inhibitory activities of the target compounds against HDAC6 and HDAC1 were screened by fluorescence analysis. Most of the target compounds showed moderate inhibitory activity against HDAC6（IC50=44-598 nmol/L）. Among them, compound A-4 displayed the highest selectivity against HDAC6 and similar inhibitory activity（IC50=44 nmol/L） to that of the positive drug SAHA（IC50=41 nmol/L） against HDAC6.

Molecular mechanism revealing therapeutic opportunities of histone deacetylases inhibitors in triple-negative breast cancer

Subject Code:H31With the support by the National Natural Science Foundation of China,Ministry of Science and Technology of China and Chinese Academy of Sciences,the research team led by Prof.Geng Meiyu(耿美玉)and Ding Jian(丁健)from Shanghai Institute of Materia Medica,Chinese Academy of Sciences,demonstrated the therapeutic opportunities of histone deacetylases(HDACs)inhibitors in

Epigenetic modulators for brain cancer stem cells: Implications for anticancer treatment

Primary malignant brain tumors are a major cause of morbidity and mortality in both adults and children,with a dismal prognosis despite multimodal therapeutic approaches.In the last years,a specific subpopulation of cells within the tumor bulk,named cancer stem cells(CSCs)or tumor-initiating cells,have been identified in brain tumors as responsible for cancer growth and disease progression.Stemness features of tumor cells strongly affect treatment response,leading to the escape from conventional therapeutic approaches and subsequently causing tumor relapse.Recent research efforts have focused at identifying new therapeutic strategies capable of specifically targeting CSCs in cancers by taking into consideration their complex nature.Aberrant epigenetic machinery plays a key role in the genesis and progression of brain tumors as well as inducing CSC reprogramming and preserving CSC characteristics.Thus,reverting the cancer epigenome can be considered a promising therapeutic strategy.Three main epigenetic mechanisms have been described:DNA methylation,histone modifications,and non-coding RNA,particularly microRNAs.Each of these mechanisms has been proven to be targetable by chemical compounds,known as epigeneticbased drugs or epidrugs,that specifically target epigenetic marks.We review here recent advances in the study of epigenetic modulators promoting and sustaining brain tumor stem-like cells.We focus on their potential role in cancer therapy.

Histone deacetylase inhibitor trichostatin A induced caspase-independent apoptosis in human gastric cancer cell

Background Histone deacetylase inhibitors （HDACIs） have been reported to induce apoptosis in cancer cells. The effects of trichostatin A （TSA） on gastric cancer cells have not been well characterized. This study was aimed to explore the effects and mechanisms of TSA on human gastric cancer SGC-7901 cells. Methods The cells were treated with TSA and analyzed by cell proliferation assay, Western blot, TUNEL assay, flow cytometry by fluorescein isothiocyanate （FITC） conjugated with Annexin V and PI staining, immunofluorescence analysis, analysis of subcellular fractionation, gene chips and real time polymerase chain reaction （PCR）. Results TSA could inhibit cell growth and induced apoptosis in gastric cancer SGC-7901 cells through the regulation of apoptosis-related genes, such as Bcl-2, Bax and survivin. Further study indicated that the pan-caspase inhibitor z-VAD-fmk did not inhibit the apoptosis induced by TSA, and we did not observe the cleavage of poly ADP ribose polymerase （PARP） after TSA treatment too. In addition, apoptosis inducing factor （AIF） and EndoG were found to translocate from mitochondria to nucleus in the immunofluorescence assay and the Western analysis of subcellular fractionation confirmed the result of immunofluorescence assay. Conclusions The apoptosis induced by TSA in gastric cancer SGC-7901 cells involves a caspase-independent pathway.

Epigenetic reprogramming, gene expression and in vitro development of porcine SCNT embryos are significantly improved by a histone deacetylase inhibitor--- m-carboxycinnamic acid bishydroxamide （CBHA）

Insufficient epigenetic reprogramming of donor nuclei is believed to be one of the most important causes of low development efficiency of mammalian somatic cell nuclear transfer （SCNT）. Previous studies have shown that both the in vitro and in vivo development of mouse SCNT embryos could be increased significantly by treat- ment with various histone deacetylase inhibitors （HDACi）, including Trichostatin A, Scriptaid, and m-carboxycin- namic acid bishydroxamide （CBHA）, in which only the effect of CBHA has not yet been tested in other species. In this paper we examine the effect of CBHA treatment on the development of porcine SCNT embryos. We have dis- covered the optimum dosage and time for CBHA treat- ment： incubating SCNT embryos with 2 pmol/L CBHA for 24 h after activation could increase the blastocyst rate from 12.7% to 26.5%. Immunofluorescence results showed that the level of acetylation at histone 3 lysine 9 （AcH3K9）, acetylation at histone 3 lysine 18 （AcH3K18）, and acetylation at histone 4 lysine 16 （AcH4K16） was raised after CBHA treatment. Meanwhile, CBHA treatment improved the expression of development relating genes such as pou5fl, cdx2, and the imprinted genes like igf2. Despite these promising in vitro results and histone reprogramming, the full term development was notsignificantly increased after treatment. In conclusion, CBHA improves the in vitro development of pig SCNT embryos, increases the global histone acetylation and corrects the expression of some developmentally important genes at early stages. As in mouse SCNT, we have shown that nuclear epigenetic reprogramming in pig early SCNT embryos can be modified by CBHA treatment.

Molecular determinants of the antitumor effects of trichostatin A in pancreatic cancer cells

AIM:To gain molecular insights into the action of the histone deacetylase inhibitor(HDACI) trichostatin-A(TSA) in pancreatic cancer(PC) cells.METHODS:Three PC cell lines,BxPC-3,AsPC-1 and CAPAN-1,were treated with various concentrations of TSA for def ined periods of time.DNA synthesis was assessed by measuring the incorporation of 5-bromo-2'deoxyuridine.Gene expression at the level of mRNA was quantif ied by real-time polymerase chain reaction.Expression and phosphorylation of proteins was monitored by immunoblotting,applying an infrared imaging technology.To study the role of p38 MAP kinase,the specif ic enzyme inhibitor SB202190 and an inactive control substance,SB202474,were employed.RESULTS:TSA most eff iciently inhibited BrdU incorporation in BxPC-3 cells,while CAPAN-1 cells displayed the lowest and AsPC-1 cells an intermediate sensitivity.The biological response of the cell lines correlated with the increase of histone H3 acetylation after TSA application.In BxPC-3 cells(which are wild-type for KRAS),TSA strongly inhibited phosphorylation of ERK 1/2 and AKT.In contrast,activities of ERK and AKT in AsPC-1 and CAPAN-1 cells(both expressing oncogenic KRAS) were not or were only modestly affected by TSA treatment.In all three cell lines,but most pronounced in BxPC-3 cells,TSA exposure induced an activation of the MAP kinase p38.Inhibition of p38 by SB202190 slightly but signif icantly diminished the antiproliferative effect of TSA in BxPC-3 cells.Interestingly,only BxPC-3 cells responded to TSA treatment by a signif icant increase of the mRNA levels of bax,a pro-apoptotic member of the BCL gene family.Finally,in BxPC-3 and AsPC-1 cells,but not in the cell line CAPAN-1,signif icantly higher levels of the cell cycle inhibitor protein p21Waf1 were observed after TSA application.CONCLUSION:The biological effect of TSA in PC cells correlates with the increase of acetyl-H3,p21Waf1,phospho-p38 and bax levels,and the decrease of phosphoERK 1/2 and phospho-AKT.

Epigenetic regulation of dental pulp stem cells and its potential in regenerative endodontics

Regenerative endodontics(RE)therapy means physiologically replacing damaged pulp tissue and regaining functional dentin–pulp complex.Current clinical RE procedures recruit endogenous stem cells from the apical papilla,periodontal tissue,bone marrow and peripheral blood,with or without application of scaffolds and growth factors in the root canal space,resulting in cementum-like and bone-like tissue formation.Without the involvement of dental pulp stem cells(DPSCs),it is unlikely that functional pulp regeneration can be achieved,even though acceptable repair can be acquired.DPSCs,due to their specific odontogenic potential,high proliferation,neurovascular property,and easy accessibility,are considered as the most eligible cell source for dentin–pulp regeneration.The regenerative potential of DPSCs has been demonstrated by recent clinical progress.DPSC transplantation following pulpectomy has successfully reconstructed neurovascularized pulp that simulates the physiological structure of natural pulp.The self-renewal,proliferation,and odontogenic differentiation of DPSCs are under the control of a cascade of transcription factors.Over recent decades,epigenetic modulations implicating histone modifications,DNA methylation,and noncoding(nc)RNAs have manifested as a new layer of gene regulation.These modulations exhibit a profound effect on the cellular activities of DPSCs.In this review,we offer an overview about epigenetic regulation of the fate of DPSCs;in particular,on the proliferation,odontogenic differentiation,angiogenesis,and neurogenesis.We emphasize recent discoveries of epigenetic molecules that can alter DPSC status and promote pulp regeneration through manipulation over epigenetic profiles.

The combination of chidamide with the CHOEP regimen in previously untreated patients with peripheral T-cell lymphoma: a prospective, multicenter, single arm, phase 1b/2 study

Objective:To assess the efficacy and safety of the novel histone deacetylase inhibitor,chidamide,in combination with cyclophosphamide,doxorubicin,vincristine,etoposide,and prednisone(Chi-CHOEP)for untreated peripheral T-cell lymphoma(PTCL).Methods:A prospective,multicenter,single arm,phase 1 b/2 study was conducted.A total of 128 patients with untreated PTCL(18–70 years of age)were enrolled between March 2016 and November 2019,and treated with up to 6 cycles with the Chi-CHOEP regimen.In the phase 1 b study,3 dose levels of chidamide were evaluated and the primary endpoint was determination of the maximumtolerated dose and recommended phase 2 dose(RP2 D).The primary endpoint of the phase 2 study was 2-year progression-free survival(PFS).Results:Fifteen patients were enrolled in the phase 1 b study and the RP2 D for chidamide was determined to be 20 mg,twice a week.A total of 113 patients were treated at the RP2 D in the phase 2 study,and the overall response rate was 60.2%,with a complete response rate of 40.7%.At a median follow-up of 36 months,the median PFS was 10.7 months,with 1-,2-,and 3-year PFS rates of 49.9%,38.0%,and 32.8%,respectively.The Chi-CHOEP regimen was well-tolerated,with grade 3/4 neutropenia occurring in approximately two-thirds of the patients.No unexpected adverse events(AEs)were reported and the observed AEs were manageable.Conclusions:This large cohort phase 1 b/2 study showed that Chi-CHOEP was well-tolerated with modest efficacy in previously untreated PTCL patients.