DADS体内诱导人胃癌细胞分化作用中组蛋白乙酰化的变化

目的观察二烯丙基二硫(DADS)在体内诱导胃癌细胞分化的作用及对人胃癌细胞移植瘤组蛋白乙酰化的影响。方法裸鼠皮下注入人胃癌细胞MGC803建立人胃癌异种移植模型,采用光学显微镜观察移植瘤细胞形态变化,流式细胞光度术和W estern b lot分析DADS对MGC803细胞移植瘤细胞周期分布的影响及瘤组织中p21WAF1蛋白、组蛋白H3、H4乙酰化的表达情况。结果腹腔注射DADS剂量为100、200 mg.kg-1时对移植瘤有明显生长抑制作用;光学显微镜显示经DADS处理后瘤细胞密度及异型性明显减小。流式细胞仪分析结果显示DADS呈浓度依赖性将移植瘤细胞阻滞在G2/M期。DADS浓度为100 mg.kg-1和200 mg.kg-1作用瘤细胞后,与对照组相比分别可使G2/M期细胞增加2.22和3.37倍。W estern b lot分析表明在G2/M期阻滞同时有组蛋白H3乙酰化表达增加,但组蛋白H4乙酰化表达水平不受DADS作用的影响;瘤组织中的p21WAF1蛋白表达量也随DADS浓度升高而上升。结论DADS对胃癌细胞裸鼠移植瘤的生长有明显抑制和诱导分化作用,这种抑制可能与其阻滞移植瘤细胞周期、上调瘤细胞组蛋白乙酰化及p21WAF1蛋白水平有关。     

DADS抑制JAK1/STAT3信号通路诱导人白血病HL-60细胞分化

目的探讨JAKs/STATs信号转导通路在二烯丙基二硫(DADS)诱导人白血病HL60细胞分化中的变化及其调控机制。方法将HL60细胞与DADS或JAKs/STATs信号通路的激酶抑制剂AG490在体外共同培养,观察细胞形态变化,检测药物作用前后细胞NBT还原能力及细胞表面分化抗原CD11b的改变;用Westernblot检测JAKs,STATs各家族成员在DADS诱导HL60细胞分化中的改变;并用免疫细胞化学法检测核转录基因STATs,cmyc,cfos,cjun的表达变化。结果DADS和AG490均可诱导HL60细胞向成熟粒系分化,且DADS在1.25mg·L-1时诱导分化作用达峰值;Westernblot检测JAK1,STAT3的酪氨酸激酶发生了磷酸化改变;免疫细胞化学示STAT3与cmyc基因蛋白核内表达下降,cjun,cfos基因蛋白核内表达上升。结论JAK1,STAT3酪氨酸激酶的磷酸化抑制参与了DADS诱导HL60细胞分化的调控,其机制可能通过调控与HL60细胞增殖分化相关的基因表达,抑制细胞DNA合成,从而抑制细胞增殖,诱导分化。DADS的作用相当于JAK1/STAT3信号通路的阻断剂。     

Inhibition of ERK and activation of p38 are involved in diallyl disulfide induced apoptosis of leukemia HL-60 cells

We investigated the effects of diallyl disulfide (DADS) on the induction of apoptosis in human Leukemia cell line HL-60 and explored the roles of mitogen-activated protein kinase (ERK and p38 MAPK) pathways in the growth inhibition and apoptosis induced by DADS. MTT assay was used to determine the DADS induced cell growth inhibition in HL-60 cells. Flow cytometry and DNA fragmentation were used to examine the roles of apoptosis in DADS-mediated cell death. Western blot analysis of the expression of phospho-MAPKs (ERK and p38) was employed to elucidate the possible mechanisms of DADS induced apoptosis. We found that growth inhibition of HL-60 cells treated with DADS exhibited a dose-dependent response (P<0.05) and DADS induced significant apoptosis. DADS at the concentration of 10 mg/L persistently activated p38 and simultaneously reduced ERK activity. PD98059, an inhibitor of ERK upstream activators MAPK kinase MKK1 and MKK2, promoted cytotoxicity and apoptosis in HL-60 cells treated with DADS. In contrast, SB203580, an inhibitor of p38, decreased cytotoxicity and apoptosis induced by DADS. Therefore, DADS can effectively inhibit the proliferation and induce apoptosis of human leukemia cell line HL-60. Inhibition of ERK signaling pathways and activation of p38 signaling pathways are likely involved in DADS induced apoptosis in HL-60 cells.     

二烯丙基二硫对人白血病HL-60细胞株survivin表达的影响

目的:观察二烯丙基二硫(diallyl disulfide,DADS)作用于人白血病HL-60细胞株后,细胞增殖及survivin蛋白表达的变化,探讨DADS对HL-60细胞增殖的影响及其机制。方法:DADS作用HL-60后,MTT法检测细胞增殖情况,SP-免疫组化法检测细胞survivin蛋白表达的变化。结果:DADS可以呈时间-浓度依赖性抑制HL-60细胞增殖并下调survivin蛋白的表达。结论:DADS能通过下调survivin蛋白的表达而抑制HL-60细胞的增殖。     

Pyranocoumarins isolated from Peucedanum praeruptorum as differentiation inducers in human leukemic HL-60 cells

Differentiation therapy for myeloid leukemia offers great potential as a supplement to the current treatment modalities. In the present report, we investigated if the pyranocoumarins, (+/-)-4'- O-acetyl-3'- O-angeloyl- cis-khellactone (or angular pyranocoumarin, APC) isolated from the medicinal plant Peucedanum praeruptorum Dunn, could induce human acute myeloid leukemic HL-60 cells to differentiate and elucidated the molecular mechanism(s) involved. The ability of HL-60 cells to reduce nitroblue tetrazolium (NBT) was significantly increased after APC treatment for 72 h. In these differentiating HL-60 cells, cell surface differentiation markers CD11b (for myeloid cells) and CD14 (for monocytic cells) were detected in 90.3 % and 70.1 % of the cells, respectively. The differentiation inducing effect of APC was time- and dose-dependent. Treatment with 20 microg/mL APC for 72 h inhibited cell growth by 90 % and cell cycle analysis revealed an increase in the proportion of G1 phase cells. In these growth-inhibited cells the expression of the cyclin-dependent kinase inhibitor p27 kip1, but not p21 WAF1, was up-regulated as shown by Western blotting. Differentiation inducing signal pathways were investigated and it was shown that phospho-MEK and phospho-ERK were elevated shortly after the addition of APC. Pre-incubation of the cells with MEK1 inhibitor PD98059 blocked this APC-induced differentiation. Our results suggest that APC are potent inducers of HL-60 cell differentiation along both the myelocytic and monocytic lineages and are potential agents for differentiation-treatment of leukemia.     

Novel dichlorophenyl urea compounds inhibit proliferation of human leukemia HL-60 cells by inducing cell cycle arrest, differentiation and apoptosis

Two novel dichlorophenyl urea compounds, SR4 and SR9, were synthesized in our laboratory and evaluated for anti-cancer activities. Specifically, we investigated the antiproliferative properties of these new compounds on promyelocytic HL-60 leukemia cells by analyzing their effects on cell differentiation, cell cycle progression and apoptosis. SR4 and SR9 were both cytotoxic to HL-60 cells in a dose-and time-dependent manner, with IC(50) of 1.2 μM and 2.2 μM, respectively, after 72 h treatment. Both compounds strongly suppressed growth of HL-60 cells by promoting cell cycle arrest at the G0/G1 transition, with concomitant decrease in protein levels of cyclins D1 and E2 and cyclin-dependent kinases (CDK 2 and CDK 4), and increased protein expression of CDK inhibitors p21(WAF1/Cip1) and p27(Kip1). In addition, either compounds induce cell differentiation as detected by increased NBT staining and expression of CD11b and CD14. Treatment with SR compounds also promoted mitochondrial-dependent apoptosis as confirmed by Annexin V-FITC double staining, DNA fragmentation, increased expression of caspase 3, 7 and 9, cytochrome c release, PARP degradation, and collapse in mitochondrial membrane potential (ΔΨ(MT)). Collectively, these results provide evidence that SR4 and SR9 have the potential for the treatment of human leukemia and merit further investigation as therapeutic agents against other types of cancer.     

二烯丙基二硫启动人白血病HL-60细胞凋亡模型的建立

目的寻找二烯丙基二硫(diallyl disulfide,DADS)诱导人白血病HL-60细胞凋亡的启动点,建立DADS启动HL-60细胞凋亡模型。方法实验设未处理组、处理组和撤药组,分别采用细胞计数、流式细胞术、DNA凝胶电泳、Western blot等方法,绘制生长曲线,检测凋亡率、活化的caspase-3表达率以及DNALadder、凋亡相关蛋白的检测。结果3.6mg.L-1DADS作用HL-60细胞1d,与对照组相比,细胞数没有明显变化,而作用2～6d,细胞数分别减少24.1%、36.5%、44.2%、52%、53.6%。DADS作用1、2d,凋亡率分别为3.1%、4.3%,与未处理组(3.0%)差异无显著性,而作用3～5d的凋亡率分别达到8.5%,15.2%,27.4%,均高于未处理组(P<0.05)。DADS作用2～5d撤药后再培养至d6,凋亡率分别为7.9%,12.4%,16.5%,18.8%,高于未处理组的3.3%(P<0.05)。处理2～5d后,活化的caspase-3的表达率分别为10.0%、10.4%、14.9%、17.3%,均高于未处理组5.4%(P<0.05)。处理组中DADS处理4d后DNA凝胶电泳出现梯状条带,而DADS作用2～5d撤药后再培养至d6均出现明显梯状条带。Westernblot结果表明,从作用2d起,caspase-3表达开始上调,而Bcl-2表达开始下调。结论3.6mg.L-1DADS诱导人白血病HL-60细胞凋亡的启动点为处理2d。     

The histone deacetylase inhibitor MS‐275 induces p21WAF1/Cip1 expression in human Hep3B hepatoma cells

MS‐275 is a novel synthetic benzamide derivative histone deacetylase (HDAC) inhibitor, that has demonstrated antiproliferative activity in a variety of in vitro human cancer cell lines including breast, colon, lung, myeloma, ovary, pancreas, prostate, and leukemia. Currently, little information is available concerning the effects of MS‐275 on liver cancer cells. In the current study, MS‐275 was found to have potent actions against human hepatoma Hep3B cells including inhibition of cell proliferation and induction of apoptosis. MS‐275 selectively up‐regulated a cyclin‐dependent kinase inhibitor, p21^WAF1/Cip1 without alteration of p27^WAF1. Expression of p21^WAF1/Cip1 is considered to play a pivotal role in Hep3B cell growth arrest and induction of apoptosis. Induction of p21^WAF1/Cip1 expression was accompanied by an accumulation of acetylated histones H3 and H4 associated specifically with p21^WAF1/Cip1 gene. ChIP analysis revealed remarkable alterations in protein components bound to the promoter region of p21^WAF1/Cip1 gene in response to MS‐275 treatment. These included the degradation of HDAC1, HDAC3, and c‐Myc, and as well as increased p300 and RNA polymerase II. The selective effect of MS‐275 on the up‐regulation of the p21^WAF1/Cip1 gene whose expression was suppressed in the hepatoma cancer cell line indicated that it would be a very attractive approach in clinical liver cancer therapy. Drug Dev Res 68:61–70, 2007. © 2007 Wiley‐Liss, Inc.     

Evidence of a functional role for p21WAF1/CIP1 down-regulation in synergistic antileukemic interactions between the histone deacetylase inhibitor sodium butyrate and flavopiridol

The functional significance of disruption of p21(WAF1/CIP1) induction by flavopiridol (FP) in human leukemia cells (Jurkat) exposed to the histone deacetylase (HDAC) inhibitor sodium butyrate (SB) was investigated. Coexposure of leukemic cells to FP blocked SB-mediated induction of p21(WAF1/CIP1) and resulted in a marked increase in mitochondrial injury, activation of procaspases-3 and -8, Bid cleavage, and PARP degradation. Enforced expression of p21(WAF1/CIP1) (i.e., in Jurkat cells inducibly expressing p21(WAF1/CIP1) under the control of a doxycycline-responsive promoter) partially but significantly reduced cytochrome c and apoptosis-inducing factor release, loss of mitochondrial membrane potential, caspase-3 and -8 activation, Bid cleavage, poly(ADP-ribose)polymerase (PARP) degradation, and apoptosis in response to SB/FP. Furthermore, increasing expression of p21(WAF1/CIP1) (i.e., by culturing cells in the presence of higher concentrations of doxycycline) rendered cells more resistant to SB/FP-mediated lethality. Enforced expression of p21(WAF1/CIP1) did not modify SB/FP-mediated JNK activation or generation of reactive oxygen species. Consistent with these results, Jurkat cells stably expressing a p21(WAF1/CIP1) nuclear localization mutant (p21DeltaNLS) were also resistant to SB/FP-mediated mitochondrial injury, activation of procaspases-3 and -8, PARP cleavage, and apoptosis. Finally, enforced expression of full-length or ectopic expression of DeltaNLS p21(WAF1/CIP1) increased the amount of p21(WAF1/CIP1) coimmunoprecipitating with procaspase-3. Together, these findings suggest that interruption of HDAC-mediated p21(WAF1/CIP1) induction by FP plays a significant functional role in potentiating apoptosis, possibly by preventing the formation of a procaspase-3/p21(WAF1/CIP1) complex.     

二烯丙基二硫对人结肠癌HT-29细胞G_1期的阻滞作用

目的探讨二烯丙基二硫(DADS)对人结肠癌HT-29细胞G1期的阻滞作用及分子机制。方法采用MTT、细胞计数法、流式细胞术和免疫细胞化学方法分析DADS对体外培养的HT-29细胞增殖抑制作用、细胞周期分布及细胞周期相关蛋白表达的影响。结果MTT法显示,60、120μmol.L-1DADS作用HT-29细胞24 h后,生长抑制率分别达23.1%、45.6%。细胞计数法表明,常规培养HT-29细胞群体倍增时间为22.58 h,60μmol.L-1DADS作用HT-29细胞后,其细胞群体倍增时间延长到31.20 h。流式细胞仪分析结果显示,60μmol.L-1DADS阻滞HT-29细胞在G1期,与对照组相比,可使G1期细胞增加约2倍,而120μmol.L-1DADS显著地将细胞阻滞在G2/M期。免疫细胞化学分析表明在G1期阻滞同时有p21W af1蛋白表达上调,Cyc lin E、C-myc蛋白表达下降。结论低剂量DADS对HT-29细胞的抑制增殖作用可能与G1期阻滞有关,DADS对HT-29细胞G1期阻滞的分子机制可能与调节p21W af1、Cyc lin E、C-myc表达相关。     

Diallyl trisulfide activates NADPH oxidase by inducing the expression of NADPH oxidase subunits and translocation of both Rac2 and p67phox subunit in HL-60 cells

Objective To explore the effect and mechanism of diallyl trisulfide on the activity of NADPH oxidase in Hl-60 cells.Methods HL-60 cells were treated with DATS at a indicated concentration for 0,1,3,6,12 hours,respectively.The activity of NADPH oxidase was measured by the reduction of the yellow dye nitroblue tetrazolium(NBT).The mRNA expression of NADPH oxidase subunits,including gp91phox,p47 phox,p22 phox,Rac2 and Rac1,was detected by RT-PCR.The protein expression of p67 phox,gp91 phox and Rac2 was analyzed by Western blot.The cell membrane fractions were prepared according to the instruction of Mem-PER kit from Pierce Corp.Results The results showed that reduction ability of HL-60 cells for NBT markedly increased in a concentration-dependent manner following DATS incubation for 3 and 6 hours(P<0.05).HL-60 cells treated by DATS at a concentration of 150 μM for 3 hours have a maximal reduction effect for NBT.The results from RT-PCR indicated that mRNA expression of NADPH oxidase subunits,including p47phox,gp91 phox,p22 phox,Rac2 and Rac1,significantly increased in a concentration-dependent manner in HL-60 cells treated by DATS.The results from western blot showed that HL-60 cells following DATS incubation have a higher level expression of Rac2 and gp91phox,compared with untreated-HL-60 cells.Our results also indicated that a maximal expression level of p47phox,gp91 phox,p22 phox,Rac2 and Rac1in HL-60 cells is present at 3 hours following DATS incubation.We found that levels of both Rac2 and p67phox was reduced in the cytosolic fraction and meanwhile increased in the membrane fraction following HL-60 exposed to DATS,Which is dependent on the concentration and time of DATS treatment.Furthermore,the level of both Rac2 and p67phox located to the plasma membrane translocation was maximized following 150 μM of DATS incubation for 3 hours.Conclusions DATS induce the activation of NADPH oxidase by both up-regulating the expression of NADPH oxidase subunit and translocating the cytosolic Rac2 and p67 phox subunit to the plasma membrane in HL-60 cells.     

新型组蛋白去乙酰化酶抑制剂致U251细胞周期阻滞、凋亡及其机制的研究

目的探讨新型组蛋白去乙酰化酶抑制剂(HDACi)2,2,3,3-四甲基环丙酰硫脲(TCCT)诱导人脑胶质瘤U251细胞周期阻滞、凋亡及其作用机制。方法以不同药物浓度与U251细胞共同培养48 h后,采用MTT法检测药物作用48 h后肿瘤细胞的增殖。药物作用24 h后,采用RT-PCR检测肿瘤细胞的p21WAF1/CIP1与Cyclin D1 mRNA的表达,Western blot检测HDAC3、HDAC4、Cyclin D1与p21WAF1/CIP1蛋白的表达,PI单染法分析细胞周期,Annexin V-PI双染法检测肿瘤细胞凋亡。结果 TCCT对U251细胞增殖具有明显抑制作用,药物干预48 h时的IC50为(0.461±0.108)mmol·L-1,并呈现剂量依赖性。TCCT药物干预24 h后U251细胞p21WAF1/CIP1mRNA表达上调,Cyclin D1 mRNA下调;组蛋白去乙酰化酶3(HDAC3)和组蛋白去乙酰化酶4(HDAC4)表达下调,Cyc-lin D1蛋白表达弱下调,p21WAF1/CIP1蛋白表达上调;S期细胞比例明显提高(P<0.05);细胞凋亡率明显增高(P<0.01)。结论 TCCT对U251细胞增殖有明显的抑制作用,引起肿瘤细胞S期阻滞和凋亡。其作用机制可能与其下调HDAC3、HDAC4表达,促进组蛋白乙酰化,而影响p21WAF1/CIP1和Cyclin D1的基因、蛋白的表达有关。     

Quantitative characterization of mitosis-blocked tetraploid cells using high content analysis

A range of cellular evidence supporting a G1 tetraploidy checkpoint was obtained from different assay methods including flow cytometry, immunoblotting, and microscopy. Cancer research would benefit if these cellular properties could instead be measured by a single, quantitative, automated assay method, such as high content analysis (HCA). Thus, nocodazole-treated cells were fluorescently labeled for different cell cycle-associated properties, including DNA content, retinoblastoma (Rb) and histone H3 phosphorylation, p53 and p21(WAF1) expression, nuclear and cell sizes, and cell morphology, and automatically imaged, analyzed, and correlated using HCA. HCA verified that nocodazole-induced mitosis block resulted in tetraploid cells. Rb and histone H3 were maximally hyperphosphorylated by 24 h of nocodazole treatment, accompanied by cell and nuclear size decreases and cellular rounding. Cells remained tetraploid and mononucleated with longer treatments, but other targets reverted to G1 levels, including Rb and histone H3 dephosphorylation accompanied by cellular respreading. This was accompanied by increased p53 and p21(WAF1) expression levels. The range of effects accompanying nocodazole-induced block of mitosis and the resulting tetraploid cells' reversal to a pseudo-G1 state can be quantitatively measured by HCA in an automated manner, recommending this assay method for the large-scale biology challenges of modern cancer drug discovery.     

Effects of FK228, a novel histone deacetylase inhibitor,on human lymphoma U-937 cells in vitro and in vivo

FK228 [(E)-(1S,4S,10S,21R)-7-[(Z)-ethylidene]-4,21-diisopropyl-2-oxa-12,13-dithia-5,8,20,23-tetraazabicyclo-[8,7,6]-tricos-16-ene-3,6,9,19,22-pentanone; FR901228, depsipeptide] is a novel histone deacetylase inhibitor that shows therapeutic efficacy in Phase I trials of patients with malignant lymphoma. However, its mechanism of action has not been characterized. In this study, we examined the in vitro and in vivo effects of FK228 on human lymphoma U-937 cells. FK228 very strongly inhibited the growth of U-937 cells with an IC(50) value of 5.92 nM. In a scid mouse lymphoma model, mice treated with FK228 once or twice a week survived longer than control mice, with median survival times of 30.5 (0.56 mg/kg) and 33 days (0.32 mg/kg), respectively (vs. 20 days in control mice). Remarkably, 2 out of 12 mice treated with FK228 (0.56 mg/kg once or twice a week) survived past the observation period of 60 days. The apoptotic population of U-937 cells time-dependently increased to 37.7% after 48 hr of treatment with FK228. In addition, FK228 induced G1 and G2/M arrest and the differentiation of U-937 cells to the CD11b(+)/CD14(+) phenotype. Expression of p21(WAF1/Cip1) and gelsolin mRNA increased up to 654- and 152-fold, respectively, after 24hr of treatment with FK228. FK228 caused histone acetylation in p21(WAF1/Cip1) promoter regions, including the Sp1-binding sites. In conclusion, (i) FK228 prolonged the survival time of scid mice in a lymphoma model, and (ii) the beneficial effects of FK228 on human lymphoma may be exerted through the induction of apoptosis, cell cycle arrest, and differentiation via the modulation of gene expression by histone acetylation.     

盐酸小檗碱对HL-60细胞增殖与分化的影响

目的　研究盐酸小檗碱对人早幼粒白血病HL 6 0细胞增殖与分化的影响。方法　应用生长曲线测定法、克隆形成实验检测药物对HL 6 0细胞生长抑制作用 ;细胞分化根据细胞形态、硝基蓝四氮唑 (NBT)还原能力、细胞表面标记的改变来决定 ;细胞周期变化用流式细胞仪测定。结果　HL 6 0细胞经小檗碱处理后生长明显受抑 ,呈时间和浓度依赖性。选择 1、2、4、8mg·L-1小檗碱作用于HL 6 0细胞 ,动态观察发现 ,HL 6 0细胞向成熟细胞分化 :细胞核变小 ,核浆比减少 ;NBT还原能力增强 ;CD11b表达升高。细胞周期分析发现 ,小檗碱处理后细胞阻滞于G0 /G1期 ,S期细胞明显减少。结论　盐酸小檗碱可抑制HL 6 0细胞的增殖 ,并诱导HL 6 0细胞向成熟细胞分化。     

Induction of CDK inhibitors (p21(WAF1) and p27(Kip1)) and Bak in the beta-lapachone-induced apoptosis of human prostate cancer cells

beta-Lapachone, a novel anti-neoplastic drug, induces various cancer cells to undergo apoptosis. In a previous report, we showed that beta-lapachone-induced apoptosis of HL-60 cells is mediated by oxidative stress. However, in the present study, we found that beta-lapachone-induced apoptosis of human prostate cancer (HPC) cells may be independent of oxidative stress. In contrast to the 10-fold beta-lapachone-induced increase in H(2)O(2) production seen in HL-60 cells, only a 2- to 4-fold increase was observed in HPC cells. N-acetyl-L-cysteine (NAC), a thiol antioxidant, inhibited the apoptosis in DU145 cells after 12 h exposure to beta-lapachone. Nonetheless, NAC, along with other antioxidants, failed to exert similar effect in HPC cells subjected to beta-lapachone treatment for 24 h. Under this premise, we suggest that the oxidative stress may not play a crucial role in beta-lapachone-mediated HPC cell apoptosis. Here we demonstrate that damage to genomic DNA is the trigger for the apoptosis of HPC cells induced by beta-lapachone. According to our results, beta-lapachone stimulates DNA dependent kinase expression and poly(ADP-ribose) polymerase cleavage in advance of significant morphological changes. beta-Lapachone promotes the expression of cyclin-dependent kinase (cdk) inhibitors (p21(WAF1) and p27(Kip1)), induces bak expression, and subsequently stimulates the activation of caspase-7 but not of caspase-3 or caspase-8 during the apoptosis of HPC cells. Taken together, these results suggest that the signaling pathway involving the beta-lapachone-induced apoptosis of HPC cell may be by DNA damage, induction of cdk inhibitors (p21 and p27), and then subsequent stimulation of caspase-7 activation.