曲古霉素A和淫羊藿甙诱导HL-60细胞分化过程中nm23和c-myc及G-CSF表达变化的研究

目的:研究曲古抑菌素A(TSA)、淫羊藿甙(ICA)诱导急性非淋巴细胞白血病HL-60细胞株分化过程中nm23基因的表达变化及其作用机制.方法:通过MTT试验检测HL-60增殖分化变化,观察细胞形态,分析表面标志和硝基四氮唑蓝(NBT)还原反应,观察HL-60细胞分化水平变化情况;通过流式细胞仪检测细胞周期的改变,RT-PCR检测nm23-H1、nm23-H2、G-CSF、c-myc基因表达的变化.结果:HL-60细胞经TSA、ICA作用后增殖受抑制,24、48和72h抑制率分别为(12.73±1.17)%、(38.15±3.32)%和(58.45±3.06)%,向成熟粒细胞系分化,细胞被阻滞在G1期,nm23、c-myc基因的表达下调,G-CSF基因表达上调.结论:HL-60细胞分化过程中c-myc基因的表达下调,G-CSF基因表达上调与下调nm23基因的表达有关.     

曲古抑菌素A诱导HL-60细胞凋亡机制的研究

目的:探讨曲古抑菌素A(TSA)在体外诱导急性早幼粒白血病HL-60细胞凋亡的机制.方法:采用MTT方法检测TSA对HL-60细胞增殖的影响.流式细胞术检测细胞周期和细胞凋亡,RT-PCR检测凋亡相关基因Bax、Caspase-9和Caspase-3的表达.结果:0.1μmol/L的TSA可明显抑制细胞增殖,P<0.01;0.05 μmol/L的TSA可使细胞周期阻滞在G0/G1期(P<0.05),但0.1 μmol/L的TSA才能引起细胞凋亡(P<0.01);经0.1 μmol/L的TSA作用12 h后,Bax、Caspase-9和Caspase-3基因表达明显升高,P<0.01.结论:TSA诱导HL-60细胞凋亡的机制在于引起细胞周期阻滞,上调Bax、Caspase-9和Caspase-3的表达.     

羧甲基茯苓多糖对IL-2促诱生效应的实验与临床研究

采用0.5％～1.0％低血清培养法较好地模拟了小剂量rhTNF-α(50U/ml)对人早幼粒白血病细胞株HL-60的增殖抑制效应,但未发现促分化作用,对细胞株c-myc基因的表达亦无明显影响;而TNF(50μ/ml)具有诱导HL-60细胞分化和抑制细胞增殖的作用,且显著抑制其c-myc癌基因的表达水平。结果表明c-myc基因表达减低主要与TNF诱导HL-60白血病细胞分化相关,并非细胞增殖受抑的结果,对癌基因表达水平的调控可能是小剂量TNF发挥分化诱导作用的重要机制。     

全反式维甲酸对HL-60细胞VEGF表达与分泌影响的分子机制研究

目的 探讨人髓系白血病细胞株HL-60在诱导分化过程中血管内皮生长因子(VEGF)表达及分泌水平变化的分子机制.方法 四甲基偶氮唑蓝(MTT)法检测HL-60细胞被全反式维甲酸(ATRA)诱导分化后的增殖水平变化,流式细胞术测定HL-60细胞CD11b表达和细胞周期的改变,半定量逆转录聚合酶链式反应(RT-PCR)检测HL-60细胞VEGF、c-myc、缺氧诱导因子(HIF)-1α、基质金属蛋白酶(MMP)-9和MMP-2 mRNA表达水平,应用酶联免疫吸附试验(ELISA)法检测药物作用前后HL-60细胞培养上清液中VEGF蛋白的含量.结果 经ATRA诱导分化后,HL-60细胞增殖水平明显降低,CD11b表达水平明显升高,出现粒系定向分化趋势,且分化程度明显升高(P<0.05),c-myc与VEGFmRNA表达水平均明显下调(P<0.05),HIF-1α mRNA表达水平则明显升高(P<0.05).用MMP-2及MMP-9抑制因子Ⅰ阻断HL-60细胞MMP-9和MMP-2表达后,细胞培养上清中VEGF蛋白分泌量明显降低(P<0.05).结论 HL-60细胞被诱导分化过程中VEGF的表达与c-myc表达正相关,与HIF-1α表达负相关.MMP-9、MMP-2可能是调控HL-60细胞分泌VEGF的主要原因之一.     

HL-60细胞高三尖杉酯碱诱导后CD44表达变化及机制的研究

目的:研究高三尖杉酯碱(homohar-ringtonine,HHT)诱导HL-60细胞分化后CD44表达变化及其与细胞周期调控的关系,探讨HHT的作用机制。方法:建立HHT诱导分化模型,瑞氏染色观察细胞形态,MTT法检测细胞增殖变化,NBT还原实验测定细胞分化状态,流式细胞术检测细胞表面CD11b表达及细胞周期变化,RT-PCR检测CD44、p27、p21和Cyclin E基因在mRNA水平的表达变化。结果:MTT实验显示,HHT对HL-60细胞产生增殖抑制作用,HL-60细胞G0/G1期细胞百分比明显上升,S期细胞百分比明显下降,P<0.05。半定量分析PCR扩增产物光密度相对表达量显示,HHT诱导后HL-60细胞中CD44基因表达逐渐减弱,p27和p21基因逐渐增强,Cyclin E基因逐渐减弱。CD44与p27表达呈明显负相关,r=-0.686,P<0.05。结论:HHT可能通过下调CD44基因,进而提高p27和p21表达,抑制Cyclin E活性而对HL60细胞产生诱导分化作用。     

曲古抑菌素A促进As2O3诱导HL-60细胞分化与分子机制的研究

目的：研究曲古抑菌素A能否促进小剂量三氧化二砷（As2O3）诱导HL-60细胞分化并对其机制进行初步探讨.方法：用MTT实验测定药物对细胞增殖的变化;流式细胞仪检测细胞表面CD11b表达率观察药物对细胞的分化作用; RT-PCR方法检测p21和cyclin D3在mRNA水平的表达变化.结果：HL-60细胞经曲古抑菌素A和（或）小剂量As2O3作用24 h后,联合用药组较单用As2O3组能明显抑制细胞增殖,促进细胞分化,p21在mRNA水平表达增加,cyclin D3在mRNA水平表达降低.结论：曲古抑菌素A能促进小剂量As2O3诱导HL-60细胞的分化,其机制可能与细胞周期蛋白cyclin D3和细胞周期蛋白依赖性激酶抑制剂p21的表达变化有关.     

巴西菇多糖诱导HL-60细胞分化的研究

目的研究巴西菇多糖诱导白血病细胞系HL-60细胞的分化作用并探讨其机制.方法采用ABC免疫染色法、硝基蓝四氮唑(NBT)还原试验、流式细胞仪、逆转录聚合酶链反应(RT-PCR)检测巴西菇多糖对HL-60细胞的诱导分化作用及其对细胞周期和癌基因表达的影响.结果巴西菇多糖0.6125g/L作用HL-60细胞4天后,CD33下降至1/3、CD11b升高至38.29%、CD15升高至56.02%,与对照组比较均有显著性差异(P＜0.001).药物作用后HL-60细胞NBT还原能力逐步增强,G2/M+S期细胞比例减少.结论巴西菇多糖可诱导HL-60细胞向成熟粒系分化:巴西菇多糖对HL-60细胞的诱导分化作用与其下调c-myc基同表达、阻滞细胞在G1期有关.     

环氧合酶-2抑制剂尼美舒利对白血病HL-60细胞增殖的抑制作用

 目的　探讨选择性环氧合酶-2（COX-2）抑制剂尼美舒利对人类急性髓系白血病HL-60细胞的增殖抑制作用。方法　以不同浓度的尼美舒利体外处理HL-60细胞,采用CCK-8、流式细胞术、Western blotting、ELISA等方法,检测尼美舒利对HL-60细胞增殖的作用及对细胞凋亡、细胞周期、COX-2、前列腺素E2（PGE2）、Bax、bcl-2、c-myc的影响。结果　尼美舒利对HL-60细胞增殖的抑制呈剂量、时间依赖性,可诱导细胞凋亡,将细胞周期阻滞于G0～G1期。尼美舒利作用HL-60细胞48 h后,细胞COX-2表达下调,100、200、400 μmol／L尼美舒利处理组与对照组HL-60细胞总凋亡率分别为（24.97±6.36）%、（34.22±5.76）%、（44.59±6.69）%及（4.11±1.26）%,差异有统计学意义（P＜0.05）。HL-60细胞合成PGE2减少,同时bcl-2、c-myc蛋白表达明显减少,Bax蛋白表达明显上调。结论　尼美舒利可抑制HL-60细胞增殖,诱导细胞凋亡,其作用与抑制COX-2表达,减少PGE2合成,阻滞细胞周期和调节凋亡相关蛋白bcl-2、c-myc、Bax的表达等有关。     

抑制c-myc基因表达对HL-60细胞表面分化抗原CD13、CD33的影响

目的:利用重组反义c-myc腺病毒载体(Ad-AS-c-myc)抑制HL-60细胞c-myc基因表达,检测细胞表面分化抗原CD13、CD33变化,了解抑制HL-60细胞c-myc表达,对细胞分化及分化抗原的影响。方法:重组Ad-AS-c-myc病毒按感染强度(MOI)为100的转染剂量,转染HL-60细胞。RT-PCR检测c-myc表达。流式细胞仪检测CD13、CD33阳性细胞率。同时对转染细胞行Wright’s染色,观察细胞形态变化。结果:Ad-AS-c-myc转染HL-60细胞后,c-myc基因表达降低,CD13阳性细胞率升高,CD33阳性细胞率降低。结论:抑制c-myc基因表达,使HL-60细胞CD13表达增强,CD33表达降低。细胞形态向成熟粒细胞方向分化。     

1,25二羟基维生素D3对体外培养的HL-60细胞的作用

[目的]研究1,25二羟基维生素D3[1,25(OH)2D3]对人HL-60细胞株生长、分化、凋亡及对维生素D受体(VDR)蛋白表达的影响.[方法]在体外用不同浓度的1,25(OH)2D3作用于对数生长期的HL-60细胞.甲基噻唑基四唑(MTT)比色法分析细胞增殖抑制作用,硝基四氮唑蓝(NBT)还原实验法分析HL-60细胞的分化指标,末端脱氧核糖核酸转移酶介导的dUTP缺口末端标记染色法(TUNEL)检测细胞晚期凋亡的变化,免疫细胞化学法检测VDR蛋白表达.[结果]不同浓度的1,25(OH)2D3作用后均可抑制HL-60细胞的生长,呈剂量和时间依赖性;可诱导HL-60细胞向成熟粒细胞分化并促其凋亡.1,25(OH)2D3作用前后HL-60细胞均表达VDR蛋白,药物作用后VDR蛋白表达上调.[结论]1,25(OH)2D3在一定浓度范围内可抑制HL-60细胞增殖,诱导细胞分化及凋亡,使VDR蛋白表达上调.     

三氧化二砷和曲古抑菌素A协同诱导HL-60细胞凋亡的作用及分子机制研究

目的 探讨三氧化二砷(As2O3)和曲古抑菌素A(TSA)在体外诱导急性早幼粒白血病细胞HL-60凋亡过程中的协同作用.方法 采用MTT法检测As2O3和(或)TSA对HL-60细胞增殖的影响,流式细胞术检测细胞周期和细胞凋亡,逆转录-聚合酶链反应(RT-PCR)检测凋亡相关基因Bax和Bcl-2的表达.结果 As2O3和TSA联用较单独用药能明显抑制细胞,引起细胞周期阻滞和凋亡,Bax基因表达升高,Bcl-2基因表达降低,Bax/Bcl-2比值升高.结论 As2O3和TSA均能够引起HL-60凋亡,二者具有协同效应,其机制是引起细胞周期阻滞,且上调Bax与Bcl-2比值.     

HL-60细胞淫羊藿甙诱导后信号传导因子表达变化与意义

目的检测急性早幼粒白血病细胞HL-60经过淫羊藿甙(ICA)诱导后信号传导与转录激活因子(STAT1、STAT3)和有丝分裂原激活蛋白激酶(p38MAPK、p42MAPK)表达变化在分化中的作用。方法建立ICA诱导分化模型,用瑞氏染色观察细胞形态,MTT实验测定细胞增殖的变化,NBT还原实验测定细胞分化状态,RT-PCR方法检测STAT1、STAT3、p38MAPK、p42MAPK 的mRNA的表达。结果 HL-60细胞经ICA作用24 h后,随着细胞增殖降低和分化的发生, p42MAPK的mRNA表达增加,STAT3的mRNA表达降低,STAT1和p38MAPK的mRNA未见明显的表达。结论 p42MAPK和STAT3与ICA诱导HL-60细胞分化有关,而p38MAPK和STAT1则与ICA诱导HL-60细胞分化无关。     

Inhibitory effects of prostaglandin A2 on c-myc expression and cell cycle progression in human leukemia cell line HL-60

The effect of prostaglandin A2 (PGA2) on c-myc expression was investigated in a human promyelocytic leukemia cell line, HL-60, which responded to PGA2 with a dose-dependent growth inhibition. Northern blot analysis indicated that treatment with PGA2 at 0.5 to 5.0 micrograms/ml remarkably reduced the steady state level of c-myc mRNA within 3 h, and then it gradually recovered according to the order of concentration of the drug. In contrast to c-myc, the level of class I HLA mRNA, as an internal control, was not diminished by PGA2 treatment. Further, this reduction of c-myc was not disturbed by cycloheximide, suggesting that this PGA2 action on c-myc expression is independent of de novo protein synthesis. Cytofluorometric analysis revealed that the exposure of HL-60 cells to PGA2 at 0.5 or 5.0 micrograms/ml arrested the cells in the G0-G1 phase of the cell cycle. This accumulation of the cells in G0-G1 phase continues until 24 or 36 h at 0.5 or 5.0 micrograms/ml, respectively. The G0-G1 arrest of the cell cycle was also recovered as the inhibition of c-myc was released. This recovery may be due to the loss of activity of PGA2 in culture medium. This study clearly showed that PGA2 treatment arrested HL-60 cells in the G0-G1 phase of the cell cycle and was associated with the reduction of c-myc mRNA.     

Differential effect of 6-ethylmercaptopurine on c-myc expression in wild-type and HGPRT-deficient HL-60 cells

Summary A variety of compounds inhibit the growth and induce differentiation of human promyelocytic leukemia (HL-60) cells. HL-60 subclones that lack the purine salvage enzyme hypoxanthine-guanine phosphoribosyl-transferase (HGPRT) can also be induced to differentiate with purine analogs. Mechanisms by which purine analogs induce differentiation offer unique possibilities for cancer chemotherapy. We have studied the effect of the purine analog 6-ethylmercaptopurine (e⁶MP) on the growth and induction of differentiation in both wild-type and HGPRT-deficient HL-60 cells. We have previously shown that e⁶MP inhibits cell growth in both wild-type and HGPRT-deficient HL-60 cells without activation through salvage pathways [8]. In this report we evaluate the effect of e⁶MP on c-myc mRNA expression. c-Myc mRNA, which is amplified in HL-60 cells, has been shown to play a role in the induction of granulocytic differentiation in HL-60 cells. e⁶MP transiently down-regulates c-myc mRNA in wild-type cells but has no efect on c-myc mRNA expression in HGPRT-deficient HL-60 cells. Despite the differential effects of e⁶MP on c-myc mRNA, both wild-type and HGPRT-deficient HL-60 cells appear to engage in terminal differentiation. The morphological changes and nonspecific esterase activity induced by e⁶MP suggest differentiation down the monocytic pathway. However, early monocytic markers such as the rapid induction of c-fos and the stabilization of c-fms mRNA are not observed. In addition, e⁶MP inhibits TPA-induced monocytic/macrophage differentiation as characterized by stabilization of c-fms mRNA and cellular adherence.Abbreviations e⁶MP 6-ethylmercaptopurine - 6-TG 6-thioguanine - MP 6-mercaptopurine - 8-AzaG 8-azaguanine - FBS fetal bovine serum - HGPRT hypoxanthine-guanine phosphoribosyltransferase Supported by grant CH-396 (R.W.T., M.R.G.) from the American Cancer Society, developmental grant IN16Y (B.T.F.) from the American Cancer Society, and grant P30-CA-16058-15 [OSUCCC] from the National Cancer Institute, Department of Health and Human Services     

The c-myc oncogene is regulated independently of differentiation in myeloid cell lines

Human myeloid leukaemia (U-937 and HL-60) cells when incubated at low cell densities with human recombinant gamma-interferon underwent functional maturation without any loss of proliferative potential relative to uninduced cells. In addition, the proportion of cells in S,G2/M and levels of c-myc oncogene (mRNA and protein) were maintained at the same level as those of untreated control cells. However, cells grown under similar conditions but with retinoic acid matured to the same extent but became growth inhibited with concomitant reductions in the proportion of cells in S,G2/M and levels of c-myc mRNA and protein. These studies indicate firstly that c-myc levels are regulated independently from differentiation in myeloid (non lymphoid) cells, secondly that gamma-interferon can induce differentiation without growth arrest under conditions of low cell density and thirdly emphasise the close association of c-myc expression with proliferative capacity.