Reorganization of actin in K-562 and HL-60 cells treated with taxol

Influence of taxol, microtubular poison, has been studied on distribution of actin. K-562 and HL-60 cells were treated with taxol in a range of concentrations 0.02-10 microM for 72 hours. The reorganization of F-actin was dependent on its dose. Phalloidin conjugated to TRITC was used to evaluate actin distribution by classical fluorescence and confocal microscopy. Actin was visualized at ultrastructural level by using a postembedding streptavidin-gold method. The treatment of K-562 and HL-60 cells with 2-10 microM of taxol resulted in an increase of F- actin in the cytoplasm, with intense labeling as a ring close to surface of the cell. In HL-60 cells a concentration of F- actin at the site of apoptotic bodies was often observed. Immunogold labeling of actin was localized in the nuclei and cytoplasm in control cells and cells treated with all doses of taxol. At higher doses, compaction of chromatin in the nucleus with strong actin labeling was observed. These observations at the ultrastructural level suggest actin involvement in chromatin reorganization during the process of apoptosis. The present study demonstrated a dose dependent reorganization of actin after treatment with taxol.     

维甲酸对HL—60细胞及NB4细胞端粒酶活性的调节

目的：探讨全反式维甲酸（ATRA）对白病细胞端粒酶活性的调节作用及其机制。方法：采用半定量端粒重复扩增－银染法对ATRA作用后HL－60,NB3细胞的端粒酶活性进行检测,并分析相对端粒酶活性与细胞分化比较之间的关系。结果：1μmol/L ATRA在诱导两种细胞分化成熟的同时,端粒酶活性显著下调,84－96h变为阴性,相对端粒酶活性（Y）与细胞分化比较（X）呈对数相关关系,其拟合对数曲线方程,HL－60细胞Y＝0．46－49．32lgX,NB4细胞Y＝2－44．79 lgX.0.1-10μmol/L ATRA在诱导两种细胞分化成熟的同时,随药物浓度增加,对端粒酶活性的抑制作用逐渐增强,ATRA直接作用于端粒酶提取液对酶活性无显著影响。结论：白血病细胞中存在失活的端粒酶活性负调控机制。恢复端粒酶活性抑制开关的正常功能可能是ATRA治疗白血病的分子机制之一。     

维甲酸对HL-60细胞及NB4细胞端粒酶活性的调节

目的 :探讨全反式维甲酸 (ATRA)对白血病细胞端粒酶活性的调节作用及其机制。方法 :采用半定量端粒重复扩增 -银染法对 ATRA作用后 HL- 6 0、NB4细胞的端粒酶活性进行检测 ,并分析相对端粒酶活性与细胞分化比例之间的关系。结果 :1μmol/L ATRA在诱导两种细胞分化成熟的同时 ,端粒酶活性显著下调 ,84～ 96h变为阴性。相对端粒酶活性 (Y)与细胞分化比例 (X)呈对数相关关系 ,其拟合对数曲线方程 ,HL- 6 0细胞 Y=0 .46 - 49.32 lg X ,NB4细胞 Y=2 - 44 .79lg X。 0 .1～ 10μmol/L ATRA在诱导两种细胞分化成熟的同时 ,随药物浓度增加 ,对端粒酶活性的抑制作用逐渐增强。 ATRA直接作用于端粒酶提取液对酶活性无显著影响。结论 :白血病细胞中存在失活的端粒酶活性负调控机制。恢复端粒酶活性抑制开关的正常功能可能是 ATRA治疗白血病的分子机制之一。     

Induction of polyploidization by jaspamide in HL-60 cells

Jaspamide, a natural peptide isolated from the marine sponge Hemiastrella minor, was used in the study of polyploidy in HL-60 cells. Jaspamide at 5 x 10(-8) M concentration exhibited antiproliferative activity and an increased CD4 and CD14 surface expression. After 2 days of cultivation, 56.3% of the exposed cells became multinuclear compared with 2.4% in controls. Moreover, the size and the number of nuclei of the cells increased in a time-dependent manner. An increased number of metaphase chromosomes was observed by microscopical enumeration after colcemid treatment for 60 min. The analysis of the DNA content of these cells, measured by propidium iodide staining, revealed a significant increase in the cells percentage with increased DNA content. Taken together, these findings indicate that the jaspamide treatment induces polyploidization in the HL-60 cell line.     

Induction of functional lipoxin A4 receptors in HL-60 cells

The appearance of [11,12-3H]lipoxin A4 (LXA4) specific binding sites was examined with human acute promyelocytic leukemic cell line 60 (HL- 60) cells exposed to either retinoic acid, phorbol 12-myristate 13- acetate (PMA), or dimethyl sulfoxide (DMSO). All three agents induced a threefold to fivefold increase in the expression of specific [11,12- 3H]LXA4 binding. Similar results were obtained in parallel with [14,15- 3H]leukotriene (LT) B4. For both 3H-ligands, homologous displacement curves were similar and independent of the agent used to induce differentiation. Specific binding of [11,12-3H]LXA4 to differentiated HL-60 cells gave a kd = 0.6 +/- 0.3 nmol/L. The appearance of both [11,12-3H]LXA4 and [14,15-3H]LTB4-specific binding sites was inhibited by actinomycin D, and LXA4 binding was sensitive to protease treatment. Specific binding of [11,12-3H]LXA4 was not evident with human platelets, red blood cells (RBCs) or the cultured B-cell (Raji), T-cell (Jurkat) lines save human endothelial cells (kd = 11.0 +/- 0.3 nmol/L). The structural specificity of induced [11,12-3H]-LXA4 recognition sites was assessed with LXB4, LTC4, LTB4, and trihydroxyhepatanoic methyl ester. Only LTC4, at 3-log molar excess, competed for 3H-LXA4-specific binding with HL-60 cells and gave a 30% reduction. The leukotriene D4 receptor antagonist SKF 104353 was ineffective in blocking [11,12- 3H]LXA4-specific binding with HL-60 cells while it competed for specific [11,12-3H]LXA4 binding with endothelial cells where LTD4 binding appears to be virtually identical to that of LXA4 binding. In addition, the LTB4 receptor antagonist ONO 4057 was ineffective at competing for [11,12-3H]LXA4 binding. When phospholipase D activation was monitored in human polymorphonuclear leukocytes (PMN) and HL-60 cells, a correlation was shown between activation and specific 3H-LXA4 binding. LXA4-induced phospholipase D (PLD) activation gave a biphasic concentration-dependent response comprised of at least two components: one phase being islet-activating protein (IAP)-sensitive (LXA4 10(-9) mol/L peak activity) and the other was staurosporine-sensitive (LXA4 10(-7) mol/L peak activity). Results indicate that HL-60 cells exposed to differentiating agents express [11,12-3H]LXA4 recognition sites also present in PMN. In addition, specific LXA4 recognition sites of myeloid cells can be distinguished by competition binding with SKF 104353 and 3H-LXA4 cross-reactivity with putative LTD4 receptors present on human endothelial cells. Moreover, they provide evidence indicating that binding of LXA4 to its recognition sites confers functional responses.     

Hyposialylation of differentiation-inducer-resistant HL-60 cells

The total sialic acid concent of retinoic acid (RA)-resistant or 6- thioguanine (6TG)-resistant HL-60 cells was more than tenfold lower and of dimethylsulfoxide (DMSO)-resistant HL-60 cells was approximately twofold lower than that of parental, wild-type (wt) HL-60 cells. Neuraminidase-inaccessible, ie residual cell-associated sialic acid after neuraminidase treatment, was four- to twelvefold lower in the three differentiation-inducer-resistant sublines than in the parent line. Neuraminidase treatment of 125I-labeled surface membrane glycoproteins (SMGs) from wt HL-60 cells converted the two-dimensional gel electrophoretic pattern to one having features in common with RA- and 6TG-resistant cells. However, neuraminidase treatment did not alter the sensitivity of wt HL-60 cells to differentiation induction by RA, hypoxanthine (purine base), or DMSO. These results indicate that differences in peripheral, neuraminidase-accessible sialic acids are important determinants of the gel electrophoretic mobility of the SMGs of the HL-60 line and sublines but are not likely related to the differentiation-resistance mechanism. Further studies are required to determine if hyposialylation of cryptic, neuraminidase-inaccessible sites has functional significance.     

Differentiation of HL-60 cells into cells with the osteoclast phenotype.

The osteoclast is the unique multinucleated cell that is responsible for bone degradation in both physiological and pathological circumstances. However, knowledge of the lineage of this inaccessible cell, the nature of its precursors, and the regulation of its formation and activation is limited and controversial. Here we show that the human promyelocytic cell line HL-60 has the potential, under the appropriate culture conditions, to differentiate into cells that have morphological and functional characteristics of osteoclasts, including multinucleation, presence of tartrate-resistant acid phosphatase activity, cross-reactivity with monoclonal antibodies that preferentially recognize osteoclasts, and capacity to resorb bone and respond to calcitonin. The multinucleated cells also contain high affinity receptors to calcitonin, in contrast to wild-type undifferentiated HL-60 cells. These data suggest that osteoclasts share a common precursor with hematopoietic cells. These undifferentiated and differentiated HL-60 cells should provide a unique model for study of the cell biology of human osteoclast differentiation, allowing molecular biological and biochemical studies heretofore not possible.     

Induction of Toll-like receptor 4 in granulocytic and monocytic cells differentiated from HL-60 cells

Toll-like receptor 4 (TLR4) is the main protein expressed on the cell surface and is an essential receptor for lipopolysaccharide (LPS) signalling in human peripheral blood leucocytes. We examined TLR4 expression and the functional response to LPS in retinoic acid-treated HL-60 cells (HL-60-derived granulocytic cells) and interferon-gamma-treated HL-60 cells (HL-60-derived monocytic cells). Slight TLR4 expression was induced in HL-60-derived granulocytic cells, while strong induction was seen in HL-60-derived monocytic cells. LPS induced interleukin 1beta (IL-1beta) production and TLR4 expression in HL-60-derived monocytic cells, but not HL-60-derived granulocytic cells. These data indicate different responses to LPS in the cells. TLR4 surface expression paralleled LPS-induced phagocytosis and TLR4-neutralizing antibody partially inhibited LPS-induced IL-8 production in HL-60-derived monocytic cells, but not in HL-60-derived granulocytic cells. These results suggest that HL-60-derived monocytic cells are partially activated via TLR4, but that HL-60-derived granulocytic cells are not activated via TLR4.     

Tumor necrosis factor-dependent production of human immunodeficiency virus 1 in chronically infected HL-60 cells

Tumor necrosis factor (TNF) may play a central role in proviral activation and release from latency in cells infected with the human immunodeficiency virus (HIV). We studied viral production and its relation to TNF in a HL-60 cell line (J22-HL-60) infected with a monocytotropic strain of HIV-1JR-FL. Viral production was stimulated to similar levels by TNF, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), and 1,25-dihydroxyvitamin D3 (1,25[OH]2D3). Production of the virus was not suppressed by 3'-azido-3'-deoxythymidine (AZT), indicating that viral production was not caused by superinfection. Low concentrations of TNF (0.1 ng/mL) induced viral production with a short lag period of 8 hours, and this proviral activation was specifically suppressed by anti- TNF antibodies. However, induction of virus production by 1,25(OH)2D3 showed an extended lag period of 2 to 3 days. The effect of 1,25(OH)2D3 on virus production was also blocked by anti-TNF antibodies, which suggests the direct participation of TNF in this process. TNF accumulated in the culture supernatant of cells stimulated with 1,25(OH)2D3 with a kinetics consistent with its involvement in the action of 1,25(OH)2D3 on viral production. The J22-HL-60 cell line produced low levels of virus when cultured in the absence of an external stimulus; however, this basal viral production was suppressed greater than 80% in the presence of anti-TNF antibodies. Corresponding low levels of TNF were detected in the culture supernatants. Viral production decreased slowly with increasing passage of the cells, and no virus was detected in the supernatants of cells maintained in culture for several months. Concomitantly, TNF was no longer detected in the supernatant of these cells, which suggests that endogenous autocrine production of TNF drives viral production in the unstimulated cells. However, viral production was stimulated in these cells by low concentrations (0.1 ng/mL) of added TNF. These results argue for a central role for TNF in HIV proviral activation in chronically infected myeloid cells.     

Autostimulation of growth by human myelogenous leukemia cells (HL-60)

We have studied the effects of medium conditioned by the human progranulocytic leukemia cell line, HL-60, on the subsequent growth of new inocula of HL-60 cells. When HL-60 cells were cultured at high cell density, optimal growth rate occurred in liquid suspension and confluent colony growth was observed in viscous medium without the addition of conditioned medium. However, when cells were cultured at lower cell density, growth rate was reduced and colony growth was nil unless conditioned medium from HL-60 culture was added. All HL-60 populations studied, including the earliest available passage, 9, both elaborated and responded to HL-60 CM. HL-60 CM did not stimulate normal human or mouse granulocyte-monocyte colony-forming cell (CFU-GM) growth. Conditioned media from other human cell lines varied in the ability to stimulate HL-60 cell and CFU-GM proliferation. Some, such as GCT CM, stimulated both HL-60 cells and normal CFU-GM, whereas others, like HL-60 CM, stimulated only HL-60 growth. The majority of cell line CMs tested did not stimulate either HL-60 or CFU-GM. Chromatography of HL-60 CM on Ultrogel AcA54 showed a single peak of HL-60 stimulating activity of apparent molecular weight 13,000. The ability of HL-60 cells to elaborate this activity provides a possible explanation for their proliferation at higher cell densities. Autostimulation may prove to be important in the high growth potential of other cell populations that undergo unrepressed proliferation.     

脂质体介导c-myc反义核酸对HL-60细胞作用的研究

目的 探讨脂质体介导ｃ－ｍｙｃ反义核酸的抗肿瘤作用。方用 用人工合成互补于ｃ－ｍｙｃ基因５’端转录起始部位的反义－寡核苷酸（ＡＳ－ＯＤＮ）,直接转染ＨＬ－６０细胞,或以脂质体ｌｉｐｏｆｅｃｔｉｎ为载体进行基因转染实验,研究ＩＬ－６０细胞的基因后的形态和功能变化。结果 脂质体介导的ｃ－ｍｙｃ反义核酸可抑制约５０％ＨＬ－６０细胞的增殖;促进细胞分化成熟,四唑氮蓝（ＮＢＴ）还原率从空白组２９％上升至５６     

BCNU-induced increase in sulfated glycosaminoglycan production by human bone marrow stromal cells

The etiology of alkylator-induced leukemia is obscure, but may be due in part to alternations in the bone marrow stromal microenvironment. Marrow extracellular matrix, including collagen, glycosaminoglycans/proteoglycans, and glycoproteins, may play a crucial role in the control of normal and abnormal hematopoiesis. Twenty-four hours after seeding, confluent human bone marrow stromal cell cultures were exposed for 3 h to 15 micrograms/ml of 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU), an alkylating agent with leukemogenic potential. On the eighth day of culture, [35S]sulfate was added and radiolabeled glycosaminoglycan(s) (GAGs) was harvested 24 h later. BCNU treatment resulted in a 104% increase of the radiolabel incorporation into cetylpyridinium chloride precipitable GAG. In addition, spectrophotometric measurement of total GAG in treated cells revealed a similar GAG increase. However, BCNU treatment did not alter compartmental GAG distribution or GAG species. Our results demonstrate a profound quantitative change in the production of important extracellular matrix components by bone marrow stromal cells after exposure to a nitrosourea. This increase may be a factor in microenvironmental alterations leading to bone marrow toxicity following alkylator exposure.     

HL-60 cells have abnormal myeloperoxidase transport and packaging

An unusual distribution of myeloperoxidase has been observed in HL-60 cells using enzyme cytochemistry and electron microscopy. Its localization in these cells differed in two ways from its previously observed distribution in normal human promyelocytes developing in vivo. First, the majority of Golgi cisternae and vesicles of HL-60 cells did not contain detectable peroxidase, whereas the rough endoplasmic reticulum (RER), granules, and dilated vacuoles were positive. This suggests that there is a block in vesicular transport from RER to the Golgi complex, or in fusion of the vesicles with Golgi membranes. Second, the peroxidase-positive granules that were formed in vitro varied greatly from those formed in vivo as follows: (1) their limiting membrane was narrower, (2) their contents were less concentrated, and (3) they resemble autophagic vacuoles rather than normal storage granules because they contained numerous membranes. These findings suggest that information gleaned from HL-60 cells about the biosynthetic pathway of myeloperoxidase and the formation of granules should be interpreted with caution.     

Expression of IMP dehydrogenase in differentiating HL-60 cells

Addition of mycophenolic acid to cultures of HL-60 cells results in a decreased cellular level of guanine nucleotides and the induction of cell differentiation. During the early stages of this induction, steady-state levels of cellular IMP dehydrogenase (IMPDH), messenger RNA (mRNA), and protein are increased, perhaps because of cellular compensation for the inhibition of IMPDH activity. The subsequent decrease in IMPH mRNA and protein levels after several days of treatment suggests a change in the control of IMPDH expression. In contrast to the pattern of increased IMPDH expression observed in the mycophenolic acid-treated cells, treatment of HL-60 cells with two other inducers of differentiation, namely retinoic acid and phorbol 12-myristate 13-acetate, resulted in stable or decreased levels of cellular IMPDH mRNA and protein. However, the kinetics of this expression were different. These results suggest that a number of factors influence the regulation of IMPDH expression during the induction of HL-60 cell differentiation, including the nature of the inducer. A decrease in the cellular IMPDH activity was observed for all of the inducers, suggesting that this decreased activity may be a determining factor in the acquisition of a mature phenotype in the HL-60 cells.     

Influence of collagen substrata on glycosaminoglycan production by B16 melanoma cells.

A cloned metastatic murine melanoma cell line exhibited similar growth characteristics when propagated on either type I collagen, type IV collagen, or plastic. However, cells grown on both types of collagen exhibited an altered cellular morphology and on type IV collagen only, an increased substrate adhesiveness, relative to those maintained on a plastic substratum. Incorporation of [3H]glucosamine and [35S]sulfate into glycosaminoglycans (GAGs) of cells grown on collagen substrates was 20% and 40% less, respectively, than cells grown on plastic, whereas degradation of cell-associated [35S]sulfate-labeled GAGs was similar in cells grown on collagen or plastic. Although the composition of GAGs was similar in all cultures, consisting of approximately 60% chondroitin and 40% heparin or heparan sulfate, the degree of sulfation of the heparin or heparan sulfate molecules was markedly decreased in cultures grown on collagen. The results indicate that the composition of the extracellular matrix influences the biological behavior of B16 melanoma cells, in part by altering the amount and nature of the GAG molecules produced.     

Hck expression correlates with granulocyte-macrophage colony- stimulating factor-induced proliferation in HL-60 cells

The human myeloid cell line HL-60 expresses approximately 300 high- affinity granulocyte-macrophage colony-stimulating factor receptors (GM- CSFRs), yet treatment of these cells with GM-CSF does not result in enhanced cellular proliferation or increases in protein tyrosine phosphorylation. In contrast, GM-CSF induces rapid increases in protein tyrosine phosphorylation and proliferative responses in HL-60 cells pretreated for 3 days in dimethyl sulfoxide (DMSO). Similarly, HL-60 cells pretreated with retinoic acid or 1,25 dihydroxyvitamin D3 were also capable of responding to GM-CSF. Interestingly, each of these treatments resulted in increased expression of the src-like tyrosine kinase hck. Stimulation with GM-CSF increased hck autophosphorylation in DMSO-treated HL-60 cells, suggesting that hck is a component of the GM-CSF signal transduction pathway. To determine if hck has a role in the DMSO-induced recoupling of the GM-CSFR, we overexpressed hck in HL- 60 cells. The resulting cell line (HL-60/hck) expresses hck mRNA and protein at levels comparable with DMSO-treated HL-60 cells. Stimulation of HL-60/hck cells with GM-CSF results in activation of hck, increases in protein tyrosine phosphorylation, and increased proliferation. These results show that cytokine receptors can exist in an uncoupled form and suggest that in HL-60 cells, appropriate levels of the src-like tyrosine kinase hck are critical for functional coupling of the GM-CSFR to biologic responses.     

Synthesis of eosinophil-associated enzymes in HL-60 promyelocytic leukemia cells

Eosinophils derived from HL-60 cells share many of the abnormalities of granule histochemistry and morphology frequently seen in eosinophils of patients with certain malignancies, especially those seen in acute myelomonocytic leukemia with abnormal eosinophils (FAB class M4eo). In order to understand the pathogenesis of these abnormalities, four enzymes, characteristic of the eosinophil, were studied in HL-60 promyelocytic leukemia cells at various stages of eosinophilic differentiation. Using biochemical and ultrahistochemical techniques, the following differences from normal eosinophil development were demonstrated. First, both myeloperoxidase and eosinophil peroxidase coexisted in the population of maturing HL-60 eosinophils. Second, the granules formed from the condensation of material in vacuoles which were derived from dilated segments of the endoplasmic reticulum; the role of the Golgi apparatus in processing of peroxidase appeared minimal. Third, low levels of lysophospholipase and arylsulfatase were present in the cells compared to normal eosinophils. Finally, crystallizations resembling precursor structures of Auer rods appeared in the granules of about 5% of the cells. These findings suggest that several disorders of the control of protein synthesis and processing exist in HL-60 eosinophils which may be responsible for the abnormal granule morphology and histochemistry.