5-aza-2’deoxycytidine联合trichostatin A抑制乳腺癌细胞增殖能力的研究

背景与目的:晚近报道应用DNA甲基转移酶抑制剂5-aza-2’deoxycytid ine(AZA)联合组蛋白去乙酰化酶抑制剂trichostatin A(TSA)作用于多种肿瘤,可以达到治疗肿瘤的目的。本文在此探讨通过AZA联合TSA作用,抑制乳腺癌细胞株增殖能力。方法:联合应用两种药物作用于肿瘤细胞,应用RT-PCR的方法检测MDA-MB-435细胞株p21和p27的mRNA转录水平的改变。通过W ST方法来检测乳腺癌细胞的增殖能力变化,将MDA-MB-435细胞根据药物处理共分四组:①对照组;②AZA+TSA组;③AZA+TSA+4-OH TAM组;④4-OH TAM组。并且采用流式细胞仪来分析肿瘤细胞周期分布的改变,将MDA-MB-435分成另外四组:①对照组;②AZA+TSA组;③AZA+TSA+E2组;④AZA+TSA+E2+4-OH TAM组。结果:TSA以及AZA联合应用能使肿瘤细胞MDA-MB-435的p27的mRNA水平增加,而p21mRNA水平略减弱。增殖分析的四个组中:AZA+TSA组细胞增殖能力减弱(P<0.01),同时出现细胞阻滞于S期,加入雌激素后细胞阻滞稍减弱。AZA+TSA+4-OH TAM组增殖能力进一步减弱(P<0.01)。4-OH TAM组增殖能力没有改变。细胞周期分析的四个组中:AZA+TSA组出现细胞阻滞于S期,AZA+TSA+E2组细胞阻滞稍减弱。AZA+TSA+E2+4-OH TAM组细胞阻滞再次提高。结论:两种药物联合应用能使得乳腺癌肿瘤细胞增殖能力下降,对于肿瘤细胞有一定抑制作用。

曲古抑菌素(Trichostatin)A对猪卵母细胞体外成熟及孤雌胚胎发育能力的影响

曲古抑菌素A(Trichostatin A,TSA)是一种组蛋白去乙酰化抑制剂,用TSA处理鼠核移植胚胎可显著提高胚胎的囊胚率。检验TSA对猪卵母细胞体外成熟以及孤雌胚胎发育的影响。在猪卵母细胞体外成熟液及胚胎培养液中添加TSA,比较不同浓度TSA对卵母细胞成熟的影响,不同浓度TSA对孤雌胚胎发育能力的影响以及TSA处理不同时间对孤雌胚胎发育能力的影响。结果发现:(1)5 nmol/L TSA处理对卵母细胞体外核成熟无显著影响,却显著提高了卵母细胞孤雌胚胎的卵裂率和囊胚率(P<0.05);(2)50 nmol/L TSA处理显著提高了孤雌胚胎的卵裂率及囊胚率(P<0.05);(3)50 nmol/L TSA处理24 h能显著提高胚胎的卵裂率及囊胚率(P<0.05,82.1%±2.6%和37.4%±3.1%)。结果表明TSA对猪卵母细胞的体外成熟及孤雌胚胎发育具有显著的促进作用。5 nmol/L的添加量对卵母细胞的体外胞质成熟具有促进作用;胚胎培养基中添加50 nmol/L TSA处理24 h能提高孤雌胚胎的发育能力。

Trichostatin A能导致小麦基因组DNA改变及甲基化修饰

为了研究组蛋白去乙酰化酶抑制剂的作用机制,本实验以组蛋白去乙酰化酶抑制剂Trichostatin A处理小麦根尖,通过随机扩增多态性DNA标记技术(random amplified polymorphic DNA,RAPD)和双限制性内切酶酶切-随机扩增法(Coupled Restriction Enzyme Digestion-Random Amplification,CRED-RA)进行探究的结果发现,与对照组相比,处理组10个随机引物的RAPD扩增条带出现83条多样性差异,多样性比例达到87.4%,同时处理组DNA甲基化比例增加.本研究证实Trichostatin A能使小麦基因组DNA发生改变,并出现了表观修饰,从而从分子和表观水平探讨了该抑制剂的作用机理.

Inhibitory Effects of 5-Aza-2'-Deoxycytidine and Trichostatin A in Combination with p53-Expressing Adenovirus on Human Laryngocarcinoma Cells

Objective： To investigate the effects of 5-Aza-2＇-deoxycytidine （5-Aza-Cdr） and trichostatin A （TSA） combined with p53-expressing adenovirus （Ad-p53） on Hep-2 cell line in vivo and in vitro, in order to explore its possibility in biological treatment of laryngocarcinoma. Methods： Effects of 5-Aza-Cdr and TSA in combination with Ad-p53 on Hep-2 cell line in vivo were determined by Cell Counting Kit-8 （CCK-8） assay. The effect of drug combination was calculated by Jin＇s formula. Effects on the cell line in vitro were investigated by establishing the nude mice model. Results： 5-Aza-Cdr and TSA showed inhibitory effects on the proliferation of Hep-2 cells in dose- and time-dependent manner. Ad-p53 can inhibit the growth of Hep-2 cells in vivo and in vitro. However, the combination of epigenetic reagents （5-Aza-Cdr/TSA） and Ad-p53 was less effective than individual use of Ad-p53. 5-Aza-Cdr and Ad-p53 inhibited the growth of transplanted tumors and reduced the volume of tumors, and the tumor volume of Ad-p53 group was significantly smaller than that of the control group （P0.05）. Conclusion： Both epigenetic reagents （5-Aza-Cdr/TSA） and Ad-p53 can suppress cell proliferation on Hep-2 in vivo and in vitro and there may be some antagonistic mechanism between Ad-p53 and epigenetic reagents （5-Aza-Cdr/ TSA）.

Trichostatin A improves the inflammatory response and liver injury in septic mice through the FoxO3a/autophagy signaling pathway

BACKGROUND:Sepsis-induced liver injury is a fatal complication of sepsis.Trichostatin A(TSA)regulates inflammation and autophagy in some human diseases,and forkhead box O3a(FoxO3a)has been shown to regulate autophagy.The present study aims to investigate whether TSA exerts its effects on septic liver injury through the FoxO3a/autophagy signaling pathway.METHODS:A sepsis mouse model was constructed by the cecal ligation and puncture(CLP)method,and AML12 cells were pretreated with lipopolysaccharide(LPS)(1μg/mL)to establish a sepsis cell model.Forty mice were divided into four groups,namely control group,TSA group,CLP group,and CLP+TSA group,with 10 mice in each group.Cells were divided into control group,TSA group,LPS group,and LPS+TSA group.Hematoxylin-eosin(H&E)staining and biochemical methods were used to evaluate liver tissue injury.Enzyme-linked immunosorbent assay(ELISA)was applied to detect the expression of proinflammatory cytokines,and Western blotting and immunofluorescence were used to measure autophagy-related protein expression.RESULTS:Compared with the CLP group(mice),the proinflammatory cytokines(interleukin-β[IL-β]2,665.27±324.90 pg/mL to 2,080.26±373.66 pg/mL;interleukin-6[IL-6]399.01±60.98 pg/mL to 221.90±46.89 pg/mL)and the hepatocyte injury markers(aspartate transaminase[AST]from 198.18±27.07 U/L to 128.42±20.55 U/L;alanine aminotransferase[ALT]from 634.98±74.10 U/L to 478.60±32.56 U/L)were notably decreased after TSA intervention.Moreover,LC3 II and FoxO3a showed an obvious increase and P62 showed an obvious decrease in the CLP+TSA group.Cell experiment results showed the similar trend.After Fox O3a gene was knocked down in AML12 cells,the promotion of autophagy and the improvement of liver enzyme index and inflammation by TSA were weakened.CONCLUSION:TSA may improve the inflammatory response and liver injury in septic mice through Fox O3a/autophagy.

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.

Mechanisms of trichostatin A inhibiting AGS proliferation and identification of lysine-acetylated proteins

AIM: To explore the effect of lysine acetylation in related proteins on regulation of the proliferation of gastric cancer cells, and determine the lysine-acetylated proteins and the acetylated modified sites in AGS gastric cancer cells. METHODS: The CCK-8 experiment and flow cytometry were used to observe the changes in proliferation and cycle of AGS cells treated with trichostatin A (TSA). Real time polymerase chain reaction and Western blotting were used to observe expression changes in p21, p53, Bax, Bcl-2, CDK2, and CyclinD1 in gastric cancer cells exposed to TSA. Cytoplasmic proteins in gastric cancer cells before and after TSA treatment were immunoprecipitated with anti-acetylated lysine antibodies, separated using sodium dodecyl sulfate polyacrylamide gel electrophoresis gel and silver-stained to detect the proteins by mass spectrometry after removal of the gel. The acetylated proteins in AGS cells were enriched with lysine-acetylated antibodies, and a high-resolution mass spectrometer was used to detect the acetylated proteins and modified sites. RESULTS: TSA significantly inhibited AGS cell proliferation, and promoted cell apoptosis, leading to AGS cell cycle arrest in G0/G1 and G2/M phases, especially G0/G1 phase. p21, p53 and Bax gene expression levels in AGS cells were increased with TSA treatment duration; Bcl-2, CDK2, and CyclinD1 gene expression levels were decreased with TSA treatment duration. Two unknown protein bands, 72 kDa (before exposure to TSA) and 28 kDa (after exposure to TSA), were identified by silver-staining after immunoprecipitation of AGS cells with the lysine-acetylated monoclonal antibodies. Mass spectrometry showed that the 72 kDa protein band may be PKM2 and the 28 kDa protein band may be ATP5O. The acetylated proteins and modified sites in AGS cells were determined. CONCLUSION: TSA can inhibit gastric cancer cell proliferation, which possibly activated signaling pathways in a variety of tumor-associated factors. ATP5O was obviously acetylated in AGS cells following TSA treatment.

TRICHOSTATIN A INHIBITS PROLIFERATION,INDUCES APOPTOSIS AND CELL CYCLE ARREST IN HELA CELLS

Objective： The histone deacetylase inhibitors （HDACIS） have been shown to inhibit cancer cell proliferation, stimulate apoptosis, an induce cell cycle arrest. Our purpose was to investigate the antiproliferative effects of a HDACI, trichostatin A （TSA）, against human cervical cancer cells （HeLa）. Methods： HeLa cells were treated in vitro with various concentrations of TSA. The inhibitory effect of TSA on the growth of HeLa cells was measured by MTT assay. To detect the characteristic of apoptosis chromatin condensation, HeLa cells were stained with Hoechst 33258 in the presence of TSA. Induction of cell cycle arrest was studied by flow cytometry. Changes in gene expression of p53, p21wafl and p27Kipl were studied by semiquantitative RT-PCR. Results： TSA inhibited cell growth in a time- and dose-dependent manner. Hoechst 33258 staining assay showed that TSA induced apoptosis. Cell cycle analysis indicated that treatment with TSA decreased the proportion of cells in S phase and increased the proportion of cells in G0/G1 and/or G2/M phases of the cell cycle. This was concomitant with overexpression of genes related to malignant phenotype, including an increase in p53, p21wall and p27Kipl. Conclusion： These results suggest that TSA is effective in inhibiting growth of HeLa cells in vitro. The findings raise the possibility that TSA may prove particularly effective in treatment of cervical cancers.

Effect and Comparison of Sodium Butyrate and Trichostatin A on the Proliferation/Differentiation of K562

In order to explore the molecular mechanisms of sodium butyrate and trichostatin A on K562 cell proliferation/differentiation, K562 cells were grown in the absence or presence of sodium butyrate or trichostatin A The percentage of viable cells was determined by trypan blue exclusion Differentiation was determined by nitro-blue tetrazolium (NBT) reduction and cell surface adhesion molecules analyzed by FACS Cell cycle distribution was studied after DNA staining by propidium iodide Cell cycle regulatory proteins were detected by Western blot and reverse transcription-polymerase chain reaction The results showed that sodiun butyrate blocked cells mainly at the G0/G1 phase of the cell cycle, whereas trichostatin A arrested the cells at G2 phase Sodium butyrate could down-regulate the mRNA expression of cyclin D1, but not affect its protein expression; down-regulate the protein expression of cyclin D3, but not affect its mRNA expression Trichostatin A showed similar effects on cyclin D1 and D3 as sodium butyrate Both sodium butyrate and trichostatin A could stimulate p21 expression of K562 cells at mRNA and protein levels It may be concluded that sodium butyrate and trichostatin A could promote the proliferation/differentiation of the K562 cells, which might be contributed to the induced expression of cyclin D3 and p21 proteins

Comparative Evaluation of the Effects of 5-Aza-2'-deoxycytidine and Trichostatin A on Reactivation of hMLH1 in COC1/DDP Ovarian Cancer Cell Line

Objective： hMLH1 protein serves to detect the DNA damage caused by cisplatin （DDP） and destroys the cell. The absence of hMLH1 expression has been correlated with acquired resistance of ovarian cancer cells to platinum. The aim of this study was to determine the possible role of DNA methylation and histone H3 lysine 9 （H3-K9） acetylation on the loss of hMLH1 expression, and to evaluate the reversal effects of 5-Aza-2＇-deoxycytidine （5-Aza-dC） and Trichostatin A （TSA） on DDP-resistance in ovarian cancer cell lines. Methods： Two human ovarian cancer cell lines, COC1 and its DDP-resistant subline, COCI/DDP were cultured. The two cancer cells were treated with 5-Aza-dC or TSA. Using COC1 cells as a control, we used methylation-specific PCR （MSP） to analyze DNA methylation at hMLHI gene promoter, hMLH1 mRNA and protein expressions were analyzed by reverse transcriptase-polymerase chain reaction （RT-PCR） and Western blot. Chromatin immunoprecipitation assay （CHIP） was used to test the levels of histone H3-K9 acetylation at hMLH1 gene promoter. Results： In COC1 cells, there was no DNA methylation at hMLH1 gene promoter, while there were hMLH1 mRNA and protein expression. In COC1/DDP cells, there was DNA hypermethylation at hMLH1 gene promoter, while there was no hMLH1 mRNA or protein expression. The treatment with 5-Aza-dC resulted in DNA demethylation at the promoter region, as well as restoration of hMLH1 expression in COC1/DDP cells. The treatment with TSA had no effects on DNA demethylation or restoration of hMLH1 expression in COC1/DDP cells. Conclusion： Hypermethylation of DNA at the promoter is related to the silencing of hMLH1 in COC1/DDP ovarian cancer cells. DNA methylation at hMLH1 promoter could play a significant role in determining the sensitivity of ovarian cancer to DDP. The drug resistance mediated by methylation of hMLH1 could be overcome by 5-Aza-dC.

Anticancer Activities of Trichostatin A on Maligant Lymphoid Cells

The anticancer activity of trichostain A （TSA） on human B cell non-Hodgkin＇s lymphoma and its mechanism were explored, The effect of TSA on the growth of Raji cells and normal peripheral blood mononuclear cells （NPBMNC） was studied by MTr assay, The effect of TSA on the apoptosis of Raji cells and NPBMNC was studied by flow cytometry and TDT-mediated dUTP nick end labeling （TUNEL）. The effect of TSA on the cell cycle of Raji cells was studied by propidium iodide method. The results showed that TSA potently inhibited proliferation of Raji cells at microgram concentrations and induced apoptosis of Raji cells in a time-and concentration-dependent manner. Treatment with TSA induced accumulation of cells in G0/G1 or G2/M and a concomitant decrease of cell population in S phase. However, NPBMNC was less sensitive to the cytotoxic effect of TSA than Raji cells. It was concluded that TSA may inhibit the proliferation of Raji cells by regulating the cell cycle and inducing the cell apoptosis. Moreover, TSA demonstrates low toxicity in NPBMNC but selectively induces apoptosis of Raji cells.

Regulation of Histone Acetylation and Apoptosis by Trichostatin in HL-60 Cells

Summary: In order to examine the strong anticancer action and low toxicity of Trichostatin A (TSA), the effect of TSA was examined on the growth inhibition, acetylation of histone H_3 and apoptosis in HL-60 cells by employing MTT, immunocytochemical techniques, and Annexin-V-FITC/PI assay. Our results showed that TSA could inhibit proliferation of HL-60 cells in a time-and dose-dependent manner, and the IC_~50 at the 36th h was 100 ng/ml. The apoptosis-inducing effect of TSA on HL-60 cells was also time-and dose-dependent. But it didn't demonstrate apparent apoptosis induction in NPBMNCs within specific dose and time range. Both of the acetylation of histone H_3 in HL-60 cells and NPBMNCs increased significantly (P<0.05) after treated with 100 ng/ml TSA for 4 h. However, there was no significant differences between the two groups (P>0.05). It is concluded that TSA can inhibit growth and induce apoptosis of HL-60 cells in a time-and dose-dependent manner, and is able to selectively induce apoptosis in HL-60 cells but does not respond in NPBMNCs under the same conditions. The difference of TSA between HL-60 cells and NPBMNCs can't be explained by the regulation of histone acetylation.

Trichostatin A Regulates hGCN5 Expression and Cell Cycle on Daudi Cells in vitro

The expression of human general control of amino acid synthesis protein 5 （hGCN5） in human Burkitt＇s lymphoma Daudi cells in vitro, effects of Trichostatin A （TSA） on cell proliferation and apoptosis and the molecular mechanism of TSA inhibiting proliferation of Daudi cells were investigated. The effects of TSA on the growth of Daudi cells were studied by 3-（4, 5-dimethyl-2-thiazolyl）-2,5-diphenyl-2H-tetrazolium （MTT） assay. The effect of TSA on the cell cycle of Daudi cells was assayed by a propidium iodide method. Immunochemistry and Western blot were used to detect the expression of hGCN5. The proliferation of Daudi cells was decreased in TSA-treated group with a 24 h IC50 value of 415.3979 μg/L. TSA induced apoptosis of Daudi cells in a timeand dose-dependent manner. Treatment with TSA （200 and 400 μg/L） for 24 h, the apoptosis rates of Daudi cells were （14.74±2.04） % and （17.63±1.25） %, respectively. The cell cycle was arrested in G0/G1 phase （50, 100 μg/L） and in G2/M phase （200 μg/L） by treatment with TSA for 24 h. The expression of hGCN5 protein in Daudi cells was increased in 24 h TSA-treated group by immunochemistry and Western blot （P〈0.05）. It was suggested that TSA as HDACIs could increase the expression of hGCN5 in Daudi cells, and might play an important role in regulating the proliferation and apoptosis of B-NHL cell line Daudi cells.

Microarray Study of Mechanism of Trichostatin A Inducing Apoptosis of Molt-4 Cells

Histone deacetylase was overexpressed in a variety of cancers and was closely correlated with oncogenic factors. The histone deacetylase inhibitor, trichostatin A （TSA） was shown to induce apoptosis in many cancer cells. However, the mechanism of TSA on induction of cancer cells apoptosis is poorly understood. This study was designed to characterize the global gene expression profiles before and after treatment of human leukemia cell line Molt-4 with TSA. Flow cytometry, MTT and DNA ladder were used to observe the effect of TSA on the apoptosis of MOLT-4 cells and normal human peripheral blood mononuclear cells （PBMC）. Microarray, reverse transcription-polymerase chain reaction （RTopCR） and Western blotting were used to detect the difference of gene and protein expressions of Molt-4 cells after incubation of the cells with TSA. The results showed that TSA could induce Molt-4 apoptosis in dose- and time-dependent manners but spared PBMCs. Microarray analysis showed that after incubation with TSA for 9 h, 310 genes were upregulated and 313 genes were deregulated. These genes regulate the growth, differentiation and survival of cells. Among these genes, STATSA was down-regulated by 80.4% and MYC was down-regulated by 77.3%. It was concluded that TSA has definite growth-inhibiting and apoptosis-inducing effects on Molt-4 cells in time- and dose-dependent manners, with weak cytotoxic effects on PBMCs at the same time. The mechanism of TSA selectively inducing apoptosis and inhibiting growth may be ascribed to the changes of pro-proliferation genes and anti-apoptosis genes.

Cell-Cycle-Dependent Variations in the FTIR Spectroscopy of HeLa Cells Treated with Trichostatin A

It is quite complex to evaluate the mechanism of action for antitumor drugs on cancer cells.Studies have pointed out that there is an unique advantage of Fourier transform infrared spectrum to obtain a fingerprint of all molecules present in the cells when cancer cells were exposed to anti-cancer drugs.Trichostatin A(TSA) is a most potent reversible inhibitor of mammalian histone deacetylases.It can inhibit cancer cell growth in vitro and in vivo.In the present study,HeLa cells were exposed to 0,50,100,200,300 and 400 nmol·L-1 TSA,and FTIR spectra were applied to evaluate the effect of TSA on cancer cells.Results show that there is some significant relationship between the changes in FTIR absorption and cell cycle arresting.On the other hand,this investigation shows that the concentration of TSA had to be more than 200 nmol·L-1 in order to ensure A1 080 cm-1/A1 540 cm-1≥1 for inhibiting cell proliferation.

The histone deacetylase inhibitor trichostatin A induces cell cycle arrest and rapid upregulation of gadd45β in LS174T human colon cancer cells

Histone deacetylase (HDAC) inhibitors are considered as promising therapeutic agents against several malignant diseases because they inhibit cancer cell proliferation. The stress sensor genes of the growth arrest and DNA damage-inducible protein (gadd45) family exhibit disordered expression in several types of malignant diseases and are thus a novel target for cancer therapy. However, there have been only few investigations of whether HDAC inhibitors affect the expression of gadd45 genes. We examined the effects of a HDAC inhibitor, trichostatin A (TSA), on the time-dependent expression of gadd45 genes in the human colon cancer cell line LS174T. Addition of TSA to LS174T cells induced inhibition of cell proliferation by arresting the cell cycle. We found that TSA treatment of LS174T cells induced rapid upregulation of gadd45β mRNA expression within 15 min, reaching a peak level at 3 h. Although the time-dependent expression pattern of gadd45β mRNA was similar to that of gadd45β mRNA, the peak level of gadd45β was lower than that of gadd45β. TSA treatment also upregulated the mRNA level of p21Waf1/Cip1, a prolif- eration inhibitor, after 3 h, but downregulated the mRNA levels of cyclin D1, a proliferation inducer, after 3 h, and of c-Myc after 1 h. TSA treatment induced a certain level of apoptosis, but the mRNA level of p53, a potent apoptosis inducer, was down-regulated after 3 h. These results suggest that the up-regulation of p21Waf1/Cip1 and apoptosis was independent of p53 and that the early upregulation of gadd45β gene, which precedes the upregulation of p21Waf1/Cip1 and the downregulation of cyclin D1, are important in TSA-treated LS174T cells.

Gastric cancer cell lines induced by trichostatin A

AIM: To explore the effect of trichostatin A (TSA) on apoptosis and acetylated histone H3 levels in gastric cancer cell lines BGC-823 and SGC-7901. METHODS: The effect of TSA on growth inhibition and apoptosis was examined by MTT, fluorescence microscopy and PI single-labeled flow cytometry. The acetylated histone H3 level was detected by Western blot. RESULTS: TSA induced apoptosis in gastric cancer cell lines BGC-823 and SGC-7901 was in a dose and time-dependent manner. Apoptotic cells varied significantly between TSA treated groups (37.5 ng/mL 72 h for BGC-823 cell line and 75 ng/mL 72 h for SGC-7901 cell line) and control group (0.85 ± 0.14 vs 1.14 ± 0.07, P = 0.02; 0.94 ± 0.07 vs 1.15 ± 0.06, P = 0.02). Morphologic changes of apoptosis, including nuclear chromatin condensation and fluorescence strength, were observed under fluorescence microscopy. TSA treatment in BGC-823 and SGC-7901 cell lines obviously induced cell apoptosis, which was demonstrated by the increased percentage of sub-G1 phase cells, the reduction of G1-phase cells and the increase of apoptosis rates in flow cytometric analysis. The result of Western blot showed that the expression of acetylated histone H3 increased in BGC-823 and SGC-7901 TSA treatment groups as compared with the control group.CONCLUSION: TSA can induce cell apoptosis in BGC-823 and SGC-7901 cell lines. The expression of acetylated histone H3 might be correlated with apoptosis.

Trichostatin A在体内对鸡胚翅芽发生中基因表达模式的作用

表观遗传和染色质重塑参与了胚胎形成及肿瘤发生,乙酰化作用是调控基因转录的关键修饰之一,组蛋白去乙酰基酶抑制剂被视为肿瘤治疗中最有前景的药物开发目标.然而哪些基因在体内对乙酰化作用修饰更敏感?这些基本问题仍未完全知晓.以鸡胚翅芽作为实验模型,用HDAC抑制剂trichostatin A(TSA)处理翅芽,研究翅芽发生中一系列基因对TSA的反应.结果显示,TSA(75μmol/L)能够改变某些对翅芽发育具有重要功能的基因的表达水平,其中SF/HGF和Twist1基因的表达被上调;FGF8,Shh,TCF4,Myf5及MyoD基因的表达被下调;与此不同,Pax3,Paraxis,CREB和PCNA基因的表达水平不受TSA作用的影响.结果提示,发育的鸡胚翅芽能够作为一个便利的、供体内研究HDACs抑制剂对基因表达作用的模型,有助于提高对染色质重塑和表观遗传对基因表达的调控作用,以及对正在开发的抗癌药物的认识.

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.

The secondary laticifer differentiation in rubber tree is induced by trichostatin A, an inhibitor of histone acetylation

The secondary laticifer, a specific tissue in the secondary phloem of rubber tree, is differentiated from the vascular cambia. The number of the secondary laticifer in the trunk bark of rubber tree is positively correlated with rubber yield. Although jasmonates have been demonstrated to be crucial in the regulation of secondary laticifer differentiation, the mechanism for the jasmonate-induced secondary laticifer differentiation remains to be elucidated.By using an experimental morphological technique, the present study revealed that trichostatin A(TSA), an inhibitor of histone deacetylation, could induce the secondary laticifer differentiation in a concentrationdependent manner. The results suggest that histone acetylation is essential for the secondary laticifer differentiation in rubber tree.