Mechanical properties of HL60 cells: role of stimulation and differentiation in retention in capillary-sized pores

Neutrophil sequestration in pulmonary capillaries occurs prior to the development of lung injury, but the mechanisms by which neutrophils are retained are unclear. We hypothesized that decreases in cell deformability, in the absence of an increase in cell surface adhesive properties, would be sufficient to cause cell retention in a filtration apparatus modeling the pulmonary microvasculature. The myelomonocytic cell line (HL60 cell line) was used to test the hypothesis since these cells were unable to increase adherence in response to n-formylmethionylleucylphenylalanine (FMLP) in either the undifferentiated state or when differentiated towards granulocytes. With differentiation, HL60 cell volume decreased, and f-actin organization changed from a thick cortical rim with focal areas of f-actin in undifferentiated cells to a thin rim in differentiated cells. Differentiated cells responded to FMLP by reorganizing f-actin and increasing stiffness. Undifferentiated cells did not exhibit changes in f-actin with stimulation, were stiffer than differentiated cells, and did not increase stiffness in response to FMLP. Cytochalasin D (CD), which disrupted the cytoarchitecture as assessed by confocal microscopy but did not affect cell volume or adherence, decreased the stiffness of undifferentiated and FMLP-stimulated differentiated cells, thus suggesting the importance of microfilament organization in the stiffness of these cells. Filtration of cells through 8-microns pores showed that undifferentiated cells were markedly retained and did not exhibit any further retention with FMLP. Differentiated cells exposed to FMLP exhibited a concentration-dependent increase in retention in 8-microns pores that was abolished by CD. In addition, CD reduced retention of undifferentiated cells, indicating that microfilament organization is an important factor in determining a cell's rheologic properties. In conclusion, FMLP-stimulated microfilament reorganization, which increased cell stiffness, was sufficient in the absence of adherence factors to cause cell retention in a filtration system. This lends support to the hypothesis that decreases in cell deformability contribute to neutrophil retention in the pulmonary microvasculature.     

CpG-ODN诱导白血病HL60细胞分化和凋亡的研究

目的:研究含CpG基序的寡核苷酸对白血病HL60细胞的作用。方法:设计合成含CpG基序的寡核苷酸(CpG-ODN)、不含CpG基序的寡核苷酸(nonCpG-ODN)和含甲基化CpG基序的寡核苷酸(ZpG-ODN)分别作用于白血病HL60细胞,MTT法测定HL60细胞抑制效应,硝基四氮唑蓝还原实验和细胞表面CD14分子表达状况分析HL60细胞诱导分化结果,流式细胞仪和透射电镜观察HL60细胞的凋亡现象,免疫组化检测HL60细胞后caspase3、Bcl-2和Bax的表达状况。结果:CpG-ODN对白血病HL60细胞有诱导分化和诱导凋亡作用,nonCpG-ODN和ZpG-ODN无此作用。结论:CpG-ODN可直接诱导白血病HL60细胞分化和凋亡,此为白血病免疫治疗提供了新的途径。     

高三尖杉酯碱对HL60细胞凋亡的影响及机制的研究

目的:研究高三尖杉酯碱对HL60细胞凋亡的影响及其机制。方法:运用高三尖杉酯碱作用HL60细胞后撤药实验筛选其诱导HL60细胞凋亡启动时相,流式细胞和免疫组化技术检测高三尖杉酯碱诱导HL60细胞凋亡启动时相凋亡信号分子Bcl-2、Bax、Fas/FasL、caspase-3、ERK2和p38的表达状况。结果:在高三尖杉酯碱诱导HL60细胞凋亡启动时相,Bcl-2表达降低,Bax表达增高,Bcl-2/Bax比值降低,ERK2表达减低,p38表达增加,caspase-3表达增加,Fas/FasL分子的表达无显著变化。结论:Bcl-2、Bax、MAPK途径和caspase-3参与高三尖杉酯碱启动HL60细胞凋亡的信号转导。     

消减免疫法制备抗HL60、HL60/ADR表面抗原差异抗体

目的:建立可特异识别HL60和HL60/ADR细胞膜表面差异蛋白的抗体库,制备单克隆抗体并研究其生物学活性。方法:通过Cp诱导的消减免疫法免疫BALB/c小鼠,采用传统杂交瘤技术制备可特异识别两种细胞差异膜蛋白的单克隆抗体;采用FACS和激光共聚焦显微镜鉴定其和两种靶细胞结合的特异性和差异性。结果:获得51株候选的差异抗体,成功筛选并纯化其中一株单抗(5F6)。5F6与可特异稳定的识别HL60/ADR细胞,结合率扣除本底为68.2%,而该抗体与HL60细胞的结合率为17%。结论:SI结合差异筛选的方法是制备差异抗体便捷可行的方法,所获得的单克隆抗体与HL60和HL60/ADR细胞膜蛋白结合有特异性和差异性,实验中所获得的单抗是寻找肿瘤耐药的新靶点和发现肿瘤耐药新机制的工具,为研究这些问题开拓了新思路。     

荧光示踪PLGA纳米粒与HL60细胞间相互作用

目的 纳米粒作为药物载体在临床诊断和治疗中有着广泛的研究和应用,其跨细胞膜进入细胞内部的过程与其生物效应直接相关,研究纳米粒与细胞间相互作用可揭示其相关机制.方法 通过荧光示踪法研究荧光素标记的PLGA纳米粒与HL60细胞间相互作用,采用激光共聚焦显微镜定量分析了纳米粒的入胞进程.结果 PLGA纳米粒与HL60细胞间相互作用具有很强的温度依赖性,其中受体介导的细胞内吞机制在纳米粒的入胞过程中起到了重要作用.结论 PLGA纳米粒与HL60细胞间相互作用的研究为纳米药物的设计和应用提供了一定的理论基础.     

人参皂苷Rh2调节白血病细胞增殖分化的作用

目的:观察人参皂苷Rh2对白血病细胞HL60增殖分化的影响.方法:免疫印迹法及流式细胞分析法分别检测未处理组HL60细胞及药物处理组HL60细胞的核增殖抗原(PCNA)及成熟粒细胞表面抗原分子CD15的表达水平.结果:药物处理组的HL60细胞体积增大,形状不规则;与未处理组HL60细胞相比,药物处理组的HL60细胞增殖...     

钙离子载体诱导HL-60细胞分化成树突状细胞的实验研究

目的 :探讨一种钙离子载体 (calciumionophore,CI)A2 3187,能否诱导早幼粒白血病细胞株HL 6 0分化成具有活性的树突状细胞 (dendriticcells,DCs)。方法 :将生长状态良好的HL 6 0细胞分别加在普通培养液中 ,或在含不同浓度 (2 5～ 16 0 0 μg/L)的A2 3187及 10 0 μg/L重组人粒 /单集落刺激因子 (rhGM CSF)的普通培养液中培养。 2 4～ 96h后 ,在光镜及电镜下观察细胞的形态 ;用流式细胞仪检测细胞的表面标志 ,MTT比色法检测其刺激同种异体T细胞增殖的作用。结果 :HL 6 0细胞以适量 (2 0 0 μg/L)的A2 3187诱导 2 4h ,DC的特征性表面标志CD83分子的表达最高 ,72h可出现典型的树突状突起 ,96h细胞表面CD80 (B7.1)、CD86 (B7.2 )、MHC II分子及细胞间黏附分子CD5 4的表达最高 ,且能明显激活同种异体T细胞。结论 :钙离子载体A2 3187可将HL 6 0细胞诱导成具有活性的DC样细胞。     

Nucleotide-, chemotactic peptide- and phorbol ester-induced exocytosis in HL-60 leukemic cells

Undifferentiated and differentiated HL-60 leukemic cells possess nucleotide receptors which functionally couple to phospholipase C via pertussis toxin-sensitive guanine nucleotide-binding proteins (G-proteins). We investigated the role of extracellular nucleotides in the regulation of beta-glucuronidase release in HL-60 cells. In dibutyryl cyclic AMP (Bt2cAMP)-differentiated HL-60 cells, the chemotactic peptide, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMet-Leu-Phe), the phosphorothioate analogue of ATP, adenosine 5'-O-[3-thio]triphosphate (ATP[gamma S]), and UTP increased cytosolic Ca2+ from 100 nM up to 1.2 microM with EC50 values of 4 nM, 1 microM and 100 nM, respectively. In these cells, ATP[gamma S] induced exocytosis with an EC50 of 4 microM and an effectiveness amounting to 50-70% of that of fMet-Leu-Phe. ATP, ITP, UTP, CTP, and uridine 5'-O-[2-thio]diphosphate activated exocytosis as well. Phorbol myristate acetate (PMA) induced exocytosis with an EC50 of 115 ng/ml and an effectiveness similar to that of ATP[gamma S]. Cytochalasin B (CB) differently potentiated exocytosis induced by ATP[gamma S], fMet-Leu-Phe and PMA. Treatment of Bt2cAMP-differentiated HL-60 cells with pertussis toxin (500 ng/ml) for 24 h resulted in ADP-ribosylation of more than 97.5% of the G-proteins. Under these conditions, pertussis toxin almost completely inhibited the increase in cytosolic Ca2+ and beta-glucuronidase release induced by fMet-Leu-Phe but only partially inhibited the effects of ATP[gamma S] and UTP. fMet-Leu-Phe at a non-stimulatory concentration (1 nM) potentiated ATP[gamma S]-induced beta-glucuronidase release in the presence but not in the absence of CB. In contrast, ATP[gamma S] and fMet-Leu-Phe synergistically activated superoxide formation in the absence of CB. PMA potentiated superoxide formation induced by ATP[gamma S] or fMet-Leu-Phe and did not affect exocytosis induced by ATP[gamma S] or fMet-Leu-Phe. In undifferentiated HL-60 cells, fMet-Leu-Phe, ATP[gamma S], UTP and PMA did not induce beta-glucuronidase release. fMet-Leu-Phe did not increase cytosolic Ca2+ in undifferentiated HL-60 cells, whereas ATP[gamma S] and UTP were similarly potent and effective as in Bt2cAMP-differentiated cells. In differentiated HL-60 cells, fMet-Leu-Phe induced aggregation, and ATP[gamma S] induced a transient shape change. Our results show (I) that exocytosis in HL-60 cells does not obligatorily depend on CB. (II) Purine and pyrimidine nucleotides activate exocytosis via pertussis toxin-sensitive and -insensitive signal transduction pathways.(ABSTRACT TRUNCATED AT 400 WORDS)     

下调GINS2表达抑制HL60细胞周期调控因子

目的 观察下调GINS2的表达后对人白血病细胞系HL60周期调控因子的变化并探讨其机制.方法 脂质体介导并稳定转染干扰质粒的细胞为于扰组,转染阴性对照质粒的细胞为阴性对照组,只加入脂质体的细胞为空白对照组,未转染的HL60细胞为未处理组.集落形成实验测定细胞增殖;流式细胞术分析细胞周期;3 H-TdR掺人实验检测细胞DNA合成;Western blot检测CDK1、cyclinB1等蛋白;RT-PCR检测ATM,CHK2,P53等mRNA水平;Western blot检测其蛋白水平.结果 和其他3组相比,干扰组细胞G2期细胞数明显增加、DNA合成受阻、增殖减慢.与G2期相关周期调控蛋白CDK1,cyclinB1的表达随时间变化而明显降低.和其他3组相比,干扰组细胞ATM,CHK2,P53转录水平和翻译水平显著上调.结论 下调GINS2表达后可抑制HL60细胞DNA复制并影响其G2期进程,机制可能与ATM,CHK2,P53等基因相关.     

Requirement of MEF2D in the induced differentiation of HL60 promyeloid cells

The regulatory role of MEF2 (myocyte enhancer binding factor 2) proteins in nonmuscle tissues has not been well characterized. We examined the expression of MEF2 family members, namely, MEF2A, -B, -C, and -D, in the differentiation of HL60 promyeloid cells and observed the remarkable increase in the expressions of MEF2A and MEF2D proteins during the differentiation process into monocytes. To examine the role of MEF2, we expressed a dominant-negative form of MEF2D, without its transactivation domain, in HL60 cells. When the HL60 cell line expressing the mutant MEF2D was induced to differentiate by VitD₃ treatment, cell surface expression of CD14 and the ability to reduce NBT, which are important characteristics of differentiated monocytes, were significantly decreased compared with control HL60 cells. These results show that MEF2D is required in the differentiation process along the monocyte/macrophage lineage,     

Livin反义寡核苷酸对人HL60细胞增殖和凋亡的影响

目的 探讨Livin mRNA反义寡核苷酸（ASODN）对人白血病细胞（HL60）增殖及凋亡的影响。方法 用免疫组织化学检测Livin蛋白表达,设计合成特异性的Livin硫代磷酸ASODN及其对照错义寡核苷酸（MSODN）,脂质体转染HL60细胞。用四甲基偶氮唑盐光吸收法(MTT)检测细胞增殖,反转录-聚合酶链反应（RT-PCR）检测Livin mRNA的表达,原位末端标记技术（TUNEL）、电镜检测细胞凋亡率和形态学改变。结果Livin ASODN在终浓度为600nmol／L作用HL60细胞48h时,能明显地抑制其增殖,降低Livin mRNA的表达,HL60细胞在形态学上出现明显的凋亡改变,细胞凋亡率显著增加 (P<0.01)。结论Livin ASODN可有效抑制HL60细胞的增殖,下调Livin基因表达,并促进HL60细胞凋亡,在诱导肿瘤细胞凋亡、抑制增殖中发挥重要作用。     

Poly-l-arginine and anN-formylated chemotactic peptide act synergistically with lectins and calcium ionophore to induce intense chemiluminescence and superoxide production in human blood leukocytes

Various cationic polyelectrolytes (poly--amino acids and histones), lectins, the chemotactic peptide, f-methionyl-leucyl-phenylalanine (fMLP), the calcium ionophore A23187, and phorbol myristate acetate (PMA) were investigated regarding their capacity to induce luminol-dependent chemiluminescence (LDCL) and superoxide production by human blood leukocytes. Although when tested individually, poly-l-arginine (PARG), phytohemagglutinin (PHA), concanavalin A (Con A), or fMLP induced only a low to moderate LDCL response, very intense synergistic CL reactions were obtained by mixtures of PARG + PHA, PARG + Con A, PARG + PHA + fMLP, Ca² + ionophore + PARG + PHA + fMLP, and PARG + PMA. The sequence of addition of the various agents to WBC in the presence of luminol absolutely determined the intensity of the LDCL signals obtained, the highest reactions being achieved when the WBC were preincubated for 2–3 rain with A23187 followed by the sequential addition of fMLP, PARG, and PHA. These multiple hits induced CL reactions which were many times higher than those obtained by each factor alone. On the other hand, neither poly-L-lysine, poly-L-ornithine, poly-L-histidine, nor poly-L-asparagine, when employed at equimolar concentrations, cooperated efficiently with PHA and fMLP to trigger synergistic LDCL response s in leukocytes. Concomitantly with the induction of LDCL, certain ligand mixtures also triggered the production of superoxide. The LDCL which was induced by the cocktail of agents was markedly inhibited by sodium azide (93% inhibition), but to a lesser extent by catalase (10% inhibition) or by snperoxide dismutase (20%-60% inhibition). On the other hand, scavengers of singlet oxygen and OH' (sodium benzoate, histidine) did not affect the synergistic LDCL responses induced by these multiple ligands. Cytochalasin B also markedly inhibited the LDCL responses induced either by soluble stimuli or by streptococci preopsonized either with histone or with polyanethole sulfonate. The LDCL responses which were induced by mixtures of PARG and concanavalin A were also strongly inhibited by mannose, a-methyl mannoside, and poly-L-glutamic acid: The data suggest that the LDCL responses induced by the soluble ligands involved a myeloperoxidase-catalyzed reaction. The possible employment of cocktails of ligands to enhance the bactericidal effects of PMNs, macrophages, and natural killer cells on microbial cells and mammalian targets is discussed.This work was supported by research grants obtained from Dr. Samuel Robbins of Cleveland, Ohio, who also kindly donated one of the LKB luminometers, and by the Swedish Medical Research Council grant B81-16X-04211-04. Part of this work was performed during the tenure of Isaac Ginsburg as a visiting professor at the University of Lund.     

Impaired stimulus-response coupling in association with increased growth rate of HL60 cells.

Impairments in the respiratory burst and stimulus-response coupling were studied with respect to the increased rate of cell replication that occurred in HL60 cells during repetitive passages in cell culture. During a 45-week period of culture, HL60 cells developed a progressive increase in rate of replication. Concomitantly, undifferentiated cells developed an impairment in ATP-induced calcium mobilization. The percentage of cells that could be differentiated with dimethyl sulfoxide progressively diminished. Differentiated cells developed an impairment in both the respiratory burst and secretion of beta-glucuronidase. In addition, regulation of the respiratory burst by cAMP agonists including isoproterenol, adenosine, and prostaglandin E2 was reduced in rapidly proliferating cells. Thus, multiple changes in stimulus-response coupling occur during cell culture in association with an increase in rate of cell replication. It may be important to recognize progressive impairments in cell function in studies using repetitive samples of HL60 cells from a continuously maintained cell population. The observed impairments in stimulus-response coupling may be relevant to unregulated cell growth in neoplastic disease.     

重组灵芝免疫调节蛋白抑制HL60细胞增殖及诱导凋亡的研究

目的:探讨重组灵芝免疫调节蛋白(rLZ-8)对HL60细胞抑制作用及诱导凋亡的研究。方法:采用MTT法检测rLZ-8对HL60细胞的体外杀伤作用;通过Annexin V/PI双染检测细胞凋亡率;应用钙离子荧光探针Fluo-3/AM染色,检测rLZ-8作用HL60细胞后细胞内钙离子浓度变化;分光光度法测定细胞caspase-3活性。结果:rLZ-8可明显抑制HL60细胞增殖,随着rLZ-8浓度增加,细胞凋亡率也增加;激光共聚焦检测细胞内钙离子水平明显升高,并且细胞内caspase-3活性增高。结论:rLZ-8可诱导HL60细胞发生凋亡,细胞内钙超载及caspase-3活性增高可能是rLZ-8诱导HL60细胞凋亡的途径之一。     

三氧化二砷逆转HL60/ADR细胞耐药的研究

背景：临床应用三氧化二砷(As₂O₃)治疗复发难治性急性早幼粒细胞白血病已获得较好效果。 目的：探讨As₂O₃逆转急性髓系白血病细胞株HL60/ADR耐药的作用及其机制。 方法：以HL60/ADR细胞为研究对象,分为空白对照组和As₂O₃组,空白对照组不加任何药物培养,As₂O₃组加入48 h IC50 As₂O₃进行培养。 结果与结论：As₂O₃能提高HL60/ADR细胞摄取阿霉素水平,降低HL60/ADR细胞多药耐药相关蛋白1表达率(P < 0.05),能够促进HL60/ADR细胞凋亡,细胞早期和晚期凋亡率均高于空白对照组(P < 0.01),并随时间增加而提高。可减低细胞IκBα、p65、抗凋亡蛋白Bcl-2表达,使促凋亡蛋白Bax,断裂的Caspase-3、Caspase-9、PARP表达升高,说明As₂O₃能够逆转HL60/ADR细胞耐药,与其上述变化有关。