Inhibition of telomerase activity and bcl-2 expression in berbamine-induced apoptosis in HL-60 cells

The present study was aimed to investigate the effect of telomerase activity in berbamine-induced apoptosis and the regulation of B cell leukemia/lymphoma 2 ( bcl-2) gene expression in human leukemia HL-60 cells. Apoptosis of HL-60 cells was induced by berbamine (10 microM) for 3, 6, 12 and 24 h. Apoptosis and bcl-2 were determined by flow cytometry analysis. A polymerase chain reaction-based telomeric repeat amplification protocol assay was used to detect the telomerase activity. Berbamine induced growth arrest and apoptotic cell death in HL-60 cells. The telomerase activity was inhibited in a time-dependent manner during the berbamine-induced apoptosis of HL-60 cells, and the expression of bcl-2 was progressively down-regulated by berbamine. Inhibition of the telomerase activity of HL-60 cells was closely related to the berbamine-induced apoptosis. The present results indicate that inhibition of telomerase and reduced bcl-2 gene expression may play a role in the berbamine-induced apoptosis of HL-60 cells.     

喜树碱诱导人白血病HL-60细胞凋亡过程中端粒酶的调控(英文)

目的:研究在喜树碱诱导人白血病HL—60细胞凋亡过程中端粒酶的调节变化规律.方法:用MTT法测定药物对细胞存活率的影响;用琼脂糖电泳及流式细胞术检测和定量凋亡的发生;用以PCR为基础的TRAP法测定端粒酶活力;逆转录PCR检测凋亡过程中bcl-2及端粒酶亚基hTR、hEST2/hTERT和TLPl/TPl的基因表达水平的变化.结果:端粒酶活力伴随喜树碱诱导HL-60细胞凋亡的发生而逐渐降低,在此过程中端粒酶各亚基的mRNA水平无可见性变化,而bcl-2的基因表达水平则相应下调.结论:端粒酶活力的下调和喜树碱诱导的HL-60凋亡密切相关,端粒酶活力的阻断并非发生在其亚基基因转录水平,bcl-2对端粒酶活力的调节也不是通过影响端粒酶亚基的转录水平来实现的.     

G-CSF对VP16诱导白血病细胞凋亡及Survivin mRNA表达的调控作用

目的：探讨粒细胞集落刺激因子（G—CSF）对足叶乙甙（VP16）诱导白血病细胞凋亡以及Survivin基因表达的影响。方法：用HL-60白血病细胞株进行传代培养，通过DNA凝胶电泳和流式细胞术（FCM）检测细胞凋亡，用RT—PCR方法检测Survivin基凶表达。结果：VP16可诱导HL-60细胞凋亡，下调Survivin表达：G—CSF可上调SurvivinmRNA表达，与VP16联合应用时，细胞凋亡率低于单独应用VP16组（P〈0．01），Survivin mRNA表达水平高于单用VP16组（P〈0．01）。结论：VP16诱导白血病细胞凋亡可能与其抑制Survivin表达有关；G—CSF能抑制VP16的促凋亡作用。     

Capsaicin potentiates 1,25-dihydoxyvitamin D3- and all-trans retinoic acid-induced differentiation of human promyelocytic leukemia HL-60 cells.

Human promyelocytic leukemia HL-60 cells are differentiated into monocytic or granulocytic lineage when treated with 1,25-dihydroxyvitamin D₃ [1,25-(OH)₂D₃] or all-trans retinoic acid, respectively. In this study, the effect of capsaicin, an active component of the red pepper of the genus Capsocum, on cell differentiation was investigated in a HL-60 cell culture system. Treatment of HL-60 cells with 5–30 μg/ml capsaicin for 72 h inhibited cell proliferation and induced a small increase in cell differentiation. Interestingly, synergistic induction of HL-60 cell differentiation was observed when capsaicin was combined with either 5 nM 1,25-(OH)₂D₃ or 50 nM all-trans retinoic acid. Flow cytometric analysis indicated that combinations of 1,25-(OH)₂D₃ and capsaicin stimulated differentiation predominantly to monocytes whereas combinations of all-trans retinoic acid and capsaicin stimulated differentiation predominantly to granulocytes. Capsaicin enhanced protein kinase C activity in 1,25-(OH)₂D₃- and all-trans retinoic acid-treated HL-60 cells. In addition, inhibitors for protein kinase C [bisindolylmaleimide (GF-109203X), chelerythrine, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7)] and an inhibitor for extracellular signal-regulated kinase [2-(2′-amino-3′-methoxyphenyl)-oxanaphthalen-4-one (PD-098059)] significantly inhibited HL-60 cell differentiation induced by capsaicin in combination with either 1,25-(OH)₂D₃ or all-trans retinoic acid. These results indicate that capsaicin potentiates 1,25-(OH)₂D₃- or all-trans retinoic acid-induced HL-60 cell differentiation and that both protein kinase C and extracellular signal-regulated kinase are involved in the cell differentiation synergistically enhanced by capsaicin.     

Toona sinensis extracts induces apoptosis via reactive oxygen species in human premyelocytic leukemia cells

Toona sinensis (T. sinensis), well known in Taiwan as a traditional Chinese medicine, has been shown to exhibit antioxidant effects. In this study, therefore, the ability of T. sinensis to induce apoptosis was studied in cultured human premyelocytic leukemia HL-60 cells. Treatment of the HL-60 cells with a variety of concentrations of the aqueous extracts of T. sinensis (TS extracts) (10–75 μg/ml) and gallic acid (5–10 μg/ml), the natural phenolic components purified from TS extracts, resulted in dose- and time-dependent sequences of events marked by apoptosis, as shown by loss of cell viability and internucleosomal DNA fragmentation. Furthermore, apoptosis in the HL-60 cells was accompanied by the release of cytochrome c, caspase 3 activation and specific proteolytic cleavage of poly (ADP-ribose) polymerase (PARP). This increase in TS extracts- and gallic acid-induced apoptosis was also associated with a reduction in the levels of Bcl-2, a potent cell-death inhibitor, and an increase in those of the Bax protein, which heterodimerizes with and thereby inhibits Bcl-2. Interestingly, TS extracts- and gallic acid-induced dose-dependent reactive oxygen species (ROS) generation in HL-60 cells. We found that catalase significantly decreased TS extracts- or gallic acid-induced cytotoxicity, DNA fragmentation, and ROS production, however, slight reduction was observed with vitamins C and E. Our results indicate that TS extracts- or gallic acid-induced HL-60 apoptotic cell death could be due to the generation of ROS, especially H₂O₂. The data suggest that T. sinensis exerts antiproliferative action and growth inhibition on HL-60 cells through apoptosis induction, and, therefore, that it may have anticancer properties valuable for application in food and drug products.     

3''取代吲哚类衍生物诱导HL-60细胞凋亡的实验研究

目的：研究3-吲哚乙基(3’-甲基-2’-酮)戊酰胺诱导HL-60细胞凋亡的作用机制。方法：用DNA琼脂糖凝胶电泳和流式细胞仪分析3-吲哚乙基(3’-甲基-2’-酮)戊酰胺对HL-60细胞的凋亡诱导作用,检测天冬酰胺特异酶切的半胱氨酸蛋白酶(Caspase)-8和Caspase-3活性来研究其对HL-60细胞的凋亡诱导途径,并通过间接免疫荧光技术检测其对Bcl-2表达的影响。结果：1．8％DNA琼脂糖凝胶电泳可观察到清晰的“DNA ladder”,流式细胞仪检测3-吲哚乙基(3’-甲基-2’-酮)戊酰胺对HL-60细胞具有明显的凋亡诱导作用。Caspase活性检测表明,Csapase-3活性明显升高而Caspase-8活性无明显变化。流式细胞仪分析表明Bcl-2的表达随着受试物浓度的升高而下降。结论：3-吲哚乙基(3’-甲基-2’-酮)戊酰胺可诱导HL-60细胞凋亡,其诱导凋亡与Bcl-2表达及Caspase-3活性有关。     

Chelerythrine and dihydrochelerythrine induce G1 phase arrest and bimodal cell death in human leukemia HL-60 cells

A quaternary benzo[c]phenanthridine alkaloid chelerythrine displays a wide range of biological activities including cytotoxicity to normal and cancer cells. In contrast, less is known about the biological activity of dihydrochelerythrine, a product of chelerythrine reduction. We examined the cytotoxicity of chelerythrine and dihydrochelerythrine in human promyelocytic leukemia HL-60 cells. After 4 h of treatment, chelerythrine induced a dose-dependent decrease in the cell viability with IC₅₀ of 2.6 μM as shown by MTT reduction assay. Dihydrochelerythrine appeared to be less cytotoxic since the viability of cells exposed to 20 μM dihydrochelerythrine for 24 h was reduced only to 53%. Decrease in the viability induced by both alkaloids was accompanied by apoptotic events including the dissipation of mitochondrial membrane potential, activation of caspase-9 and -3, and appearance of cells with sub-G1 DNA. Moreover, chelerythrine, but not dihydrochelerythrine, elevated the activity of caspase-8. A dose-dependent induction of apoptosis and necrosis by chelerythrine and dihydrochelerythrine was confirmed by annexin V/propidium iodide dual staining flow cytometry. Besides, both alkaloids were found to induce accumulation of HL-60 cells in G1 phase of the cell cycle. We conclude that both chelerythrine and dihydrochelerythrine affect cell cycle distribution, activate mitochondrial apoptotic pathway, and induce apoptosis and necrosis in HL-60 cells.     

曲古菌素A抑制HL-60细胞端粒酶活性及亚单位hTERT的表达并诱导凋亡

目的研究组蛋白去乙酰化酶抑制剂曲古菌素A(tri-chostatin A,TSA)抑制HL-60细胞端粒酶活性及亚单位hTERT的表达并诱导凋亡的机制。方法采用MTT法和倒置相差显微镜观察不同浓度曲古菌素A对HL-60细胞的抑制作用,流式细胞仪检测600 nmol.L-1TSA作用后的细胞凋亡情况,TRAP-ELISA法检测端粒酶活性变化,RT-PCR分析端粒酶三个亚单位的mRNA表达情况。结果曲古菌素A对HL-60细胞的抑制作用具有时间和剂量依赖性,Annex-inV/PI双染色体法检测凋亡显示,600 nmol.L-1TSA作用48h后,细胞凋亡率为42.6%。600 nmol.L-1曲古菌素A作用12、24和48 h后,端粒酶活性分别下降为1.95±0.25、1.73±0.12和1.52±0.09。RT-PCR显示,端粒酶逆转录酶hTERT表达下降,而端粒酶RNA模板(hTR)和端粒酶相关蛋白(hTP1)表达无明显改变。结论曲古菌素A(trichosta-tin,TSA)抑制HL-60细胞端粒酶活性下降,并诱导凋亡,其机制可能与曲古菌素A下调hTERT转录水平有关。     

四种砷拮抗剂对三氧化二坤诱导的三种粒系白血病细胞凋亡和端粒酶活性的减量调节作用

目的：研究巯基供体N-乙酰兰胱氨酸（NAC）和二巯丁二钠（NDMS）、抗氧化剂过氧化氢酶（CAT）和Ca^2 清除剂（Quin2）对三氧化二砷诱导的三种粒系白血病细胞凋亡和端粒酶活性改变的调控作用。方法：用流式细胞仪和PCR ELISA法分别检测NAC、NDMS、CAT或Quin2与三氧化二砷共同作用于三种粒系白血病细胞后其凋亡和端粒酶活性的变化。结果：三氧化二砷0.6、2.7和8.1μmol/L可分别诱导急性早幼粒细胞白血病细胞株NB4,慢性粒细胞白血病细胞株K562,急性粒细胞白血病细胞株HL-60细胞发生40%-60%的凋亡,同时下调三种细胞的端粒酶活性。NAC4mmol/L,NDMS200μmol/L,CAT80kU/L,Quin 2 20μmol/L不同程度抑制这种凋亡作用,NAC和CAT既可独立降低三种细胞的端粒酶活性,也可促进三氧化二砷对端粒酶的下调作用,而Quin2可抑制K562和HL-60细胞中的这种下调作用。结论：三氧化二砷诱导的三种细胞的凋亡过程涉及了疏基失活、自由基的改变、细胞内Ca^2 浓度改变及端粒酶活性下降,NAC、NDMS、CAT及Quin2可不同程度拮抗三氧化二砷对三种细胞的作用。     

Baicalein induced in vitro apoptosis undergo caspases activity in human promyelocytic leukemia HL-60 cells.

In this study, we evaluated the potential apoptosis effects of baicalein on human promyelocytic leukemia HL-60 cells in vitro. Apoptosis induction, cell viability, morphology and caspase-3 activity were then performed to determine by flow cytometric assay, DNA gel electrophoresis, anti-ADP-ribose stain and determination of caspase-3 activity. There is a significant difference in cell death of HL-60 cells that was detected between baicalein-treated and untreated groups. Furthermore, there was a further significant increase in apoptosis induction when cells were treated with baicalein compared to without baicalein treated groups. Flow cytometric assays and DNA fragmentation gel electrophoresis also confirmed baicalein induced apoptosis in HL-60 cells. Baicalein also promoted caspase-3 activity then leading to cleavage of poly-ADP-ribose polymerase finally leading to DNA fragmentation occurrence. Furthermore, the baicalein-induced apoptosis was markedly blocked by the broad-spectrum caspase inhibitor, z-VAD-fmk. Taken together, these results suggest that treatment of human leukemia HL-60 cells with baicalein induced apoptosis through activation of caspase-3 activity.     

Induction of apoptosis and inhibition of telomerase activity in human bone marrow and HL-60 p53 null cells treated with anti-cancer drugs.

Telomerase plays a key role in the maintenance of chromosomal stability in tumours, and the ability of anti-cancer agents to inhibit telomerase activity is under investigation. In this study, we evaluated the effect of etoposide and taxol, on the telomerase activity and telomere length in human leukaemia p53 null cells and human bone marrow cells, as well as apoptosis and cell cycle modulation. Results showed that after exposure to the drugs, HL-60 cells as well as the human progenitors underwent a block in G2 and subsequently apoptosis, whereas stromal cells from bone marrow did not undergo a block in G2 or enter apoptosis after etoposide exposure. Telomere length increased in stromal cells after treatment with both etoposide and taxol whereas in HL-60 cells only after etoposide treatment with. Bax, bcl-2 and bcl-x change their expression in stromal cells, whereas bcl-x was induced after drug treatment and bcl-2 down regulated in progenitor cells. Our data suggest that telomerase activity and apoptosis are correlated and they seem to be modulated by a common gene, bcl-2.     

高三尖杉酯碱对HL-60细胞端粒酶量的抑制效应

目的　研究高三尖杉酯碱 (HHT)对HL 6 0细胞端粒酶活性的影响及诱导凋亡作用。方法　采用端粒重复序列扩增法 (TRAP) 酶联免疫吸附试验(ELISA)检测了HL 6 0细胞的端粒酶量变化 ,用细胞形态学观察 ,DNA琼脂糖凝胶电泳 ,流式细胞术检测和DNA片段原位末端标记 (TUNEL)法检测了细胞凋亡现象。结果　 5～ 5 0 0 μg·L- 1HHT处理HL 6 0细胞 0～ 4 8h ,HL 6 0细胞端粒酶量呈剂量依赖性和时间依赖性下降。同时 ,HL 6 0细胞发生了凋亡。结论　HHT有降低HL 6 0细胞的端粒酶量 ,诱导细胞凋亡作用。     

三丁酸甘油酯对白血病细胞株HL-60体外作用的研究

目的探讨三丁酸甘油酯(TB)对白血病细胞株HL-60细胞增殖的抑制作用,并对其作用机制进行初步探讨。方法采用MTT法观察细胞增殖变化。应用免疫组化检测抑癌基因P16的表达。应用流式细胞仪观察细胞周期的改变。通过DNA电泳观察细胞凋亡。结果TB可以抑制细胞增殖。1.0 mmol/L的TB作用72 h,有典型的DNA梯形条带。细胞周期阻滞在G0/G1期。结论TB能抑制HL-60细胞增殖,诱导细胞凋亡,其机制可能与上调P16表达有关。     

DNA引物酶抑制剂碘化-3,3′-二乙基-9-甲基-硫杂羰花青诱导人白血病HL-60细胞凋亡

目的研究DNA引物酶抑制剂碘化-3,3′-二乙基-9-甲基-硫杂羰花青(DMTCCI)诱导人粒细胞性白血病HL-60细胞凋亡并探索其机制。方法分别采用不同浓度的DMTCCI处理培养于RPMI-1640培养基的HL-60细胞。采用MTT法检测DMTCCI对HL-60细胞的生长抑制作用。采用流式细胞仪和DNA琼脂糖凝胶电泳方法检测细胞凋亡。采用蛋白免疫印迹(Western blotting)法观察凋亡相关蛋白survivin， Bcl-xL， Bad， Bax， Bcl-2， caspase-9， caspase-3， caspase-6， PARP， DFF45和lamin B的表达。采用ApoAlert Caspase-3分析试剂盒检测caspase-3的活性。结果DMTCCI具有抑制人白血病HL-60细胞增殖的作用，其IC₅₀值为0.24 μmol·L^-1。流式细胞仪和DNA琼脂糖凝胶电泳结果显示，DMTCCI可诱导HL-60细胞凋亡。在经DMTCCI处理的HL-60细胞中，survivin和Bcl-xL蛋白的表达水平下调，Bad和Bax蛋白的表达水平上调，Bcl-2蛋白的表达水平无变化，caspase-9，caspase-3，caspase-6，PARP，DFF45和lamin B被分别裂解，产生相应裂解产物。在HL-60细胞中，caspase-3的活性在1 μmol·L^-1 DMTCCI处理3 h时明显升高，在处理12 h时达到最高峰。结论DMTCCI可抑制人白血病HL-60细胞的增殖并诱导其发生细胞凋亡。Bcl-2家族蛋白、survivin和caspases家族蛋白可能参与了上述诱导HL-60细胞凋亡的过程。     

DNA引物酶抑制剂碘化-3,3''-二乙基-9-甲基-硫杂羰花青诱导人白血病HL-60细胞凋亡

目的 研究DNA引物酶抑制剂碘化-3,3'-二乙基-9-甲基-硫杂羰花青(DMTCCI)诱导人粒细胞性白血病HL-60细胞凋亡并探索其机制.方法 分别采用不同浓度的DMTCCI处理培养于RPMI-1640培养基的HL-60细胞.采用MTT法检测DMTCCI对HL-60细胞的生长抑制作用.采用流式细胞仪和DNA琼脂糖凝胶电泳方法检测细胞凋亡.采用蛋白免疫印迹(Western blotting)法观察捌亡相关蛋白survivin,Bcl-xL,Bad,Bax,Bcl-2,caspase-9,caspase-3,caspase-6,PARP,DFF45和lamin B的表达.采用ApoAlert Caspase-3分析试剂盒检测caspase-3的活性.结果 DMTCCI具有抑制人白血病HL-60细胞增殖的作用,其IC50值为0.24μmol·L-1.流式细胞仪和DNA琼脂糖凝胶电泳结果显示,DMTCCI可诱导HL-60细胞凋亡.在经DMTCCI处理的HL-60细胞中,survivin和Bcl-xL蛋白的表达水平下调,Bad和Bax蛋白的表达水平上调,Bcl-2蛋白的表达水平无变化,caspase-9,caspase-3,caspase-6,PARP, DFF45和lamin B被分别裂解,产生相应裂解产物.在HL-60细胞中,caspase-3的活性在1μmol·L-1 DMTCCI处理3 h时明显升高,在处理12 h时达到最高峰.结论 DMTCCI可抑制人白血病HL-60细胞的增殖并诱导其发生细胞凋亡.Bcl-2家族蛋白、survivin和caspases家族蛋白可能参与了上述诱导HL-60细胞凋亡的过程.     

金荞麦Fr4诱导HL-60细胞凋亡及对端粒酶活性的影响

目的研究金荞麦有效部位Fr4能否诱导HL-60细胞凋亡及对端粒酶活性的影响。方法用MTT法检测Fr4对细胞增殖的影响;光学显微镜和透射电镜观察细胞形态改变;Annexin-V/PI双染法检测细胞膜介导的凋亡;琼脂糖凝胶电泳观察DNA碎片;TRAP-PCR-ELISA检测端粒酶活性。结果金荞麦Fr4 60~240 mg.L-1能诱导HL-60细胞凋亡,电镜观察到典型的凋亡细胞,电泳呈现出阶梯状条带,流式细胞仪检测到早期凋亡细胞数随剂量的增加而升高。MTT法示金荞麦Fr4抑制HL-60细胞增殖,并且呈剂量依赖性趋势,药物作用24 h的IC50为115 mg.L-1,Fr4诱导HL-60细胞凋亡过程中,端粒酶活性下降。结论金荞麦Fr4可诱导HL-60细胞凋亡,其机制可能与端粒酶活力下降有关。     

十四酰佛波乙酸酯抑制三尖杉酯碱诱导的人白血病HL—60细胞凋亡

目的：研究十四酰佛波乙酸酯（ＴＡ）预处理后，三尖杉酯碱（Ｈａｒ）和喜树碱（Ｃａｍ）诱导人白血病ＨＬ－６０细胞凋亡的变化。方法：染色质凝集观察，流式细胞术，ＤＮＡ琼脂糖凝胶电泳和点杂交。结果：ＴＡ２００ｎｍｏｌ·Ｌ＾－１预处理ＨＬ－６０细胞６ｈ，明显抑制Ｈａｒ０．１ｍｇ·Ｌ＾－１作用３ｈ诱导的细胞凋亡，但只部分抑制Ｃａｍ０．２ｍｇ·Ｌ＾－作用３ｈ诱导的细胞凋亡。ＴＡ预处理ＨＬ－６０细胞明显降低ｃ－ｍ     

Oridonin induced A375-S2 cell apoptosis via bax-regulated caspase pathway activation, dependent on the cytochrome c/caspase-9 apoptosome

Two diterpenoids, oridonin (1) and ponicidin (2), were isolated from the 95% ethanol extract of Rabdosia rubescens and were evaluated for antiproliferative activity on cancer cells and human peripheral blood mononuclear cells (PBMC) in vitro. Oridonin has much more potent cytotoxic effects on four tumor cells (human melanoma A375-S2, human cervical cancer HeLa, human breast adenocarcinoma MCF-7, murine fibrosarcoma L929) than does ponicidin. The growth-inhibitory activity of oridonin for A375-S2 cells was more potent than that for the other cell lines, with an IC₅₀ of 15.1±1.2 μmol L^-1. Treatment with oridonin (34.3 μmol L_-1) for 12 h significantly inhibited A375-S2 cell growth, and showed weaker cytotoxicity against PBMC. By contrast, ponicidin markedly inhibited the growth of PBMC under the same conditions. When caspases-3 and -8 were activated at early stages after treatment of A375-S2 cells with oridonin (34.3 μmol L_-1), apoptotic bodies were formed, nuclear damage was observed by Hoechst 33258 staining and DNA fragmentation was exhibited. In addition, oridonin increased the expression of the apoptosis inducer, Bax, promoted the release of cytochrome c without affecting Bcl-2 expression, and activated down-stream caspase-9 in the mitochondrial pathway. These observations indicated that an appropriate dose of oridonin gave an initial premitochondrial phase that involved the Bcl-2 family of the pro-apoptotic protein Bax that required the participation of caspase-9 and caspase-3. However, on treatment with oridonin (137.4 μmol L_-1) for 12 h, the majority of A375-S2 cells underwent necrosis as measured by an LDH activity-based assay. Our results suggest that oridonin induces A375-S2 cell death on the balance of apoptosis and necrosis.