Trdmt1 3'-untranslated region functions as a competing endogenous RNA in leukemia HL-60 cell differentiation

Severe blockage in myeloid differentiation is the hallmark of acute myeloid leukemia (AML). Trdmt1 plays an important role in hematopoiesis. However, little is known about the function of Trdmt1 in AML cell differentiation. In the present study, Trdmt1 was up-regulated and miR-181a was down-regulated significantly during human leukemia HL-60 cell differentiation after TAT-CT3 fusion protein treatment. Accordingly, miR-181a overexpression in HL-60 cells inhibited granulocytic maturation. In addition, our “rescue” assay demonstrated that Trdmt1 3′-untranslated region promoted myeloid differentiation of HL-60 cells by sequestering miR-181a and up-regulating C/EBPα (a critical factor for normal myelopoiesis) via its competing endogenous RNA (ceRNA) activity on miR-181a. These findings revealed an unrecognized role of Trdmt1 as a potential ceRNA for therapeutic targets in AML.     

三七皂甙R1诱导HL—60细胞系分化的形态和功能变化

用三七皂甙R_1(80μg/ml)处理HL-60细胞,发现68%的HL-60细胞向中性粒细胞分化,其中晚幼粒细胞32%,杆状核粒细胞30%,分叶核粒细胞6%;进一步实验显示分化后细胞硝基蓝四氮唑(NBT)还原能力、吞噬功能、细胞膜补体受体以及酸性磷酸酶(ACP)和β葡萄糖醛酸酶(β-Gr)活性都明显增高。结果表明,三七皂甙R_1能诱导HL-60细胞向中性粒细胞分化。     

The loss of IAP expression during HL-60 cell differentiation is caspase-independent

Human promyelocytic leukaemia cells (HL-60) differentiate into neutrophil-like cells that die spontaneously by apoptosis when treated with retinoic acid (RA). Inhibitors of apoptosis proteins (IAP) bind to and inhibit caspases 3, 7, and 9 activity and the induction of apoptosis. In this study, we demonstrate that undifferentiated HL-60 cells express IAP. During their differentiation, IAP expression is decreased at the mRNA and protein levels. In addition, we show that there is a corresponding increase in the expression and functional activity of active caspases 3 and 9. This activity was associated with the cleavage of XIAP, NAIP, and cIAP-2. Most importantly, we demonstrate that blocking caspase activity does not alter the decrease in IAP protein expression during differentiation but prevents caspase activation, IAP cleavage, and the induction of apoptosis. This result shows that the loss of IAP expression is independent of the induction of apoptosis and is solely related to the differentiation process. However, IAP cleavage is caspase-dependent. Terminal differentiation results in an altered apoptotic phenotype that is associated with the induction of HL-60 cell apoptosis.     

Autoinduction of differentiation in human myelocytic leukemia cells (HL-60-Y3)

We conducted a study on autoinduction of differentiation in human myelocytic leukemia cells (HL-60-Y3) in which the effects of serum cytodifferentiation were excluded by the use of a serum-free semisolid culture. In the culture dish the HL-60-Y3 colony count per dish was kept at 100 or below, and only the formation of clumping-type colonies, which consisted of blastoid cells, was observed. The formation of spreading-type colonies increased with the colony count and when the colony count reached 500 per dish, more than 90% of the colonies formed were spreading-type colonies. The main component cells of the spreading-type colonies were mature monocytoid cells, which were positive for alpha-naphthyl butyrate esterase. Moreover, a marked reduction in the recloning ability was observed in differentiated colonies compared to undifferentiated colonies. These results indicate the autoinduction of differentiation in human myelocytic leukemia cells. Furthermore, a single cell study that excluded the effect of colony to colony interactions suggested the presence of a differentiation autoinducing factor in the medium.     

Human leukemic models of myelomonocytic development: a review of the HL-60 and U937 cell lines

The human leukemic myeloblast HL-60 and monoblast U937 cell lines have made important contributions to the disciplines of cancer, hematology, and immunology. As sources of leukemic cells, they have been used for the study of neoplasia and therapeutics. As sources of hemic cells, they have been used for biochemical and biological analysis of regulation and differentiation in myelopoiesis. When stimulated with immunomodulatory factors, the cell lines develop properties of host-defense effector cells. They are also a source of cytokines that affect other cell types.     

In vitro detection of apoptotic stimuli by use of the HL-60 myeloid leukemic cell line.

The human histiocytic lymphoma line HL-60 has served as a model of myeloid cell differentiation and can be induced to differentiate along the neutrophil or monocytic lineage, depending on the external stimulus. The nondifferentiated cell line retains a premyeloid leukemic phenotype and is capable of anchorage-independent growth and proliferation. The role of apoptosis in the regulation of immunologic and inflammatory events associated with homeostasis and disease has been most intensively studied in lymphocytes. In the present study, nondifferentiated HL-60 has served as a model for studying myeloid cell apoptosis by investigating apoptotic changes induced by camptothecin, a DNA topoisomerase inhibitor, as well as physiologic stimuli, including ceramide analogs and a monoclonal antibody against the Fas antigen. Multiparameter flow cytometry was used to evaluate apoptosis by measuring changes in both side scatter and propidium iodide staining. The appearance of apoptotic cells was confirmed biochemically by measuring DNA endonuclease activity by both enzyme-linked immunosorbent assay quantitation and DNA ladder formation on agarose gels and morphologically with the detection of micronuclei by confocal laser microscopy. These studies demonstrate that HL-60 can serve as an in vitro model for the detection of physiologic and pharmacologic apoptotic stimuli and for understanding the early and late cellular changes associated with induction of the apoptotic program.     

Activation of human neutrophils by the air pollutant sodium sulfite (Na(2)SO(3)): comparison with immature promyelocytic HL-60 and DMSO-differentiated HL-60 cells reveals that Na(2)SO(3) is a neutrophil but not a HL-60 cell agonist

Sulfite exposure can induce inflammatory responses characterized by an influx of neutrophils into the airways leading to lung malfunctions. Studies focusing on sodium sulfite (Na(2)SO(3))/neutrophil interactions have shown that this chemical possesses proinflammatory properties based on its ability to induce a respiratory burst. Information regarding how this chemical could alter other neutrophil responses/functions as well as its role on immature promyelocytic cells is currently lacking in the literature. In this study, we report that Na(2)SO(3) can induce tyrosine phosphorylation events in human neutrophils but not in both HL-60 and HL-60 + DMSO. As a positive control, GM-CSF was found to induce tyrosine phosphorylation of a particular protein of 120-130 kDa in both HL-60 and HL-60 + DMSO cells testifying that these cells were responsive. In addition, we report that Na(2)SO(3) does not alter neutrophil phagocytosis and that this chemical increases the release of the proinflammatory cytokine IL-8 but not TNF-alpha. Paradoxically, we found that Na(2)SO(3) acts as a potent inhibitor of de novo neutrophil protein synthesis in a concentration-dependent fashion (0.1, 1, or 10 mM) as assessed by SDS-PAGE from metabolically [(35)S]-labeled cells. In contrast to mature neutrophils, we found that Na(2)SO(3) does not modulate de novo protein synthesis in HL-60 cells treated with low concentrations (0. 1 or 1 mM) and that this pollutant was toxic at 10 mM as judged by a drastic decrease of total protein content stained with Coomassie blue. We conclude that Na(2)SO(3) can activate human neutrophils and that its proinflammatory potential is further supported by its ability to increase IL-8 production. In addition, our results clearly indicate that HL-60 and HL-60 + DMSO respond differently than mature human neutrophils to the inflammatory pollutant Na(2)SO(3). Extrapolation of data obtained with HL-60 (and/or HL-60 + DMSO) to neutrophils should be taken with caution. Our data obtained with Na(2)SO(3) are an example.     

人急性髓系白血病HL-60来源的树突样细胞诱导的CTL体内外作用研究

目的 观察人急性髓系白血病HL－60来源的树突样细胞（HL－60DC）对细胞毒T淋巴细胞（CTL）的免疫调节作用。方法 采用PKC激活剂佛波酯（PMA）及细胞因子GM－CSF、IL－4、TNF－α在体外诱导培养HL－60细胞，获得具有树突状细胞形态、表型（CD1a、CD80、CD86、RelB阳性表达）的HL60DC，观察HL－60DC诱导的CTL体外抗瘤效应，并建立人白血病HL－60／SCID（严重联合免疫缺陷）小鼠异种移植模型进行过继治疗。结果 联合GM－CSF、TNF－α及PMA处理7－11d，获得的HL－60DC体外激活的CTL在体外对HL－60细胞有显著的细胞毒活性。CTL以5：1效靶比多次腹腔回输，能够明显延长荷瘤鼠存活时间，降低瘤块重量，减轻肝、脾、骨髓受肿瘤浸润程度，但流式细胞检测发现部分受治疗的存活小鼠有微小病灶的存在。结论 人急性髓系白血病HL－60来源的树突样细胞诱导的CTL在体内外有一定的抗瘤效应。     

Changes in binding of staphylococcal leukocidin to HL-60 cells during differentiation induced by dimethyl sulfoxide

The susceptibility of HL-60 cells to the cytotoxic activity of leukocidin increased depending on the degree of differentiation induced by dimethyl sulfoxide (DMSO). To compare binding characteristics of two components (S and F) of leukocidin to HL-60 and DMSO-treated HL-60 cells, the S and F components were labeled with 125I. Scatchard analysis of the binding curve of the 125I-labeled S component to HL-60 cells showed two classes of binding sites. The binding sites with higher affinity had a dissociation constant of 3.39 nM, and the number of binding sites per cell was 730. The specific binding of the 125I-labeled S component to DMSO-treated cells increased depending on the period of DMSO treatment. Scatchard analysis of the binding curve of cells treated with DMSO for 7 days gave a straight line. The dissociation constant was 1.78 nM, and the number of binding sites per cell was 6,920. The total binding of the 125I-labeled F component to DMSO-treated cells increased about twofold over binding to HL-60 cells. However, in the presence of the unlabeled S component, the increase of binding of the F component to DMSO-treated cells was much greater. These data suggested that the increased susceptibility of DMSO-treated cells to leukocidin was dependent on the changes in the number of high-affinity binding sites of the S component and of the bound F component.     

Experimental model of hemorrhagic stroke: Rabbit immunization with HL-60 promyelocytic cell differentiation factor

Rabbits immunized with synthetic HLDF differentiation factor developed hemorrhagic stroke with thrombosis of small cerebral vessels and destruction of vascular endotheliocytes. The severity of stroke correlated with serum level of antibodies to differentiation factor. The role of different sites of HLDF molecule in the induction of clinical signs of hemorrhagic stroke was studied. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 141, No. 2, pp. 237–240, February, 2006     

HL-60细胞ATRA诱导后MMP-9/TIMP-1表达的变化

为了检测HL-60细胞经过全反式维甲酸(ATRA)诱导后基质金属蛋白酶(MMP-9、MMP-2)及金属蛋白酶组织抑制剂1(TIMP-1)表达变化,并探讨其变化的意义。采用瑞氏染色观察细胞形态,WST1实验测定细胞增殖变化,NBT还原实验测定细胞分化状态,RT-PCR方法检测MMP-9、MMP-2、TIMP-1、VEGF的mRNA的表达。结果显示,HL-60细胞经ATRA作用24h后,随着细胞增殖降低与分化的发生,MMP-9mRNA表达增加,TIMP-1mRNA和VEGF表达降低,MMP-2mRNA未见明显表达。ATRA诱导HL-60细胞分化后MMP-9表达增加,而TIMP-1表达降低,MMP-9不促进HL-60细胞表达VEGF。     

Oxygen metabolism of the HL-60 cell line: comparison of the effects of monocytoid and neutrophilic differentiation

HL-60 cells are promyelocytic leukemia cells that respond to culture conditions with differentiation into granulocytelike or macrophagelike phagocytes. O2 metabolism is critical to the microbicidal function of phagocytic cells. O2 metabolism was studied in HL-60 cells differentiated with dimethylsulfoxide (Me2SO) and 1,25(OH)2D3, with the objective of 1) determining the validity of these cells as models for human neutrophils and monocytes, respectively, and 2) determining whether these cells are capable of forming hydroxyl radical. Me2SO-treated cells had morphology consistent with human neutrophils. O2 consumption by these cells in response to phorbol myristate acetate (PMA; 100 ng/ml) or opsonized zymosan (3 mg/ml) was less than that by neutrophils, as was superoxide formation. O2 metabolism was not inhibited by KCN or antimycin A. Myeloperoxidase (MPO) activity decreased during differentiation but remained greater than that of human neutrophils. Cytochalasin B enhanced recovery of superoxide secreted in response to zymosan, implying its release from the phagosome. 1,25(OH)2D3-treated cells had morphology consistent with monocytes. O2 consumption and superoxide release were less than with Me2SO-treated cells. Unlike the case with human monocytes, O2 consumption was not inhibited by KCN or antimycin A. MPO activity was minimally reduced by differentiation. Cytochalasin B inhibited recovery of superoxide. Luminol-dependent luminescence was greater among 1,25(OH)2D3-treated cells than among Me2SO-treated cells. Free radicals were also measured with a spin trapping technique using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). Spin trapping allows direct, simultaneous detection of superoxide and hydroxyl radicals. Regardless of the mechanism of differentiation, only superoxide was formed by HL-60 cells. These results show that Me2SO-treated HL-60 cells represent an excellent model for the study of human neutrophil oxidative function. However, 1,25(OH)2D3-treated cells are quite different in their O2 metabolism from peripheral blood monocytes.     

Loss of amplification and appearance of a novel translocation site of the c-myc oncogene in HL-60 leukemia cells.

The chromosomal localization of c-myc sequences was determined by in situ hybridization in HL-60 cells (HL-60a) which contain an amplified c-myc locus and in an HL-60 subline (T-HL60) which has lost the amplification and has proportionately lower levels of c-myc RNA. While in HL-60a cells amplified c-myc sequences were found on the M3q+ marker chromosome, in T-HL60 cells one or few residual c-myc copies were found on a novel 4q+ marker chromosome. Comparative phenotypic analysis of HL-60a and T-HL60 cells show that the decrease in c-myc amplification/expression is not accompanied by changes in the malignant phenotype, namely in doubling time and clonogenic capability in semi-solid media. The significance of these results is discussed in the context of the role of c-myc amplification in the establishment and/or maintenance of the leukemic phenotype in HL-60 cells. In general, these results further underscore the utility of in situ hybridization analysis in identifying oncogene translocations which are not detectable by conventional karyotypic analysis.     

HL—60细胞产生的肿瘤免疫抑制因子对T细胞的作用及其生物学特性

白血病细胞培养上清液和白血病人血清能抑制PHA—P诱导的人外周血T淋巴细胞的增殖;抑制白细胞介素2(IL—2)的产生和反应性。以正常2BS人胚肺细胞培养上清液和正常人血清作对照则无抑制作用。白血病细胞培养上清液无细胞毒作用。聚丙烯酰胺凝胶电泳(PAGE)结果表明,来源HL—60人早幼粒白血病细胞的肿瘤免疫抑制因子(tumor-derived immunosuppressive factor,TDSF)的分子量约为87KD,其化学本质为蛋白质。抗急非淋白血病药物对这种TDSF的分泌有部分抑制作用。