Quantitative morphological aspects of granulocytic differentiation induced in HL-60 cells by dimethylsulfoxide and retinoic acid

HL-60 cells differentiate to mature granulocytes when cultured with DMSO or retinoic acid. These two drugs can induce different expression of phenotypic or functional properties in these cells. The morphological characteristics of the differentiation sequences elicited by these two drugs have been therefore evaluated by a quantitative cytological analysis technique using a SAMBA 200 cell image processor. The maturation sequences induced by DMSO or retinoic acid differed mainly in nuclear geometry and cytoplasmic granules expression. Multivariate statistical analyses of data reveal that DMSO and retinoic acid elicited granulocytic maturation through two separate morphological pathways which can be individualized as early as 24 hr after differentiation induction. Image processing may therefore offer an interesting tool for studying new drugs with differentiation potential in chemotherapy.     

Granulocytic differentiation of human NB4 promyelocytic leukemia cells induced by all-trans retinoic acid metabolites

The metabolism of all-trans retinoic acid (ATRA) has been reported to be partly responsible for the in vivo resistance to ATRA seen in the treatment of human acute promyelocytic leukemia (APL). However, ATRA metabolism appears to be involved in the growth inhibition of several cancer cell lines in vitro. The purpose of this study was to evaluate the in vitro activity of the principal metabolites of ATRA [4-hydroxy-retinoic acid (4-OH-RA), 18-hydroxy-retinoic acid (18-OH-RA), 4-oxo-retinoic acid (4-oxo-RA), and 5,6-epoxy-retinoic acid (5,6-epoxy-RA)] in NB4, a human promyelocytic leukemia cell line that exhibits the APL diagnostic t(15;17) chromosomal translocation and expresses the PML-RAR alpha fusion protein. We established that the four ATRA metabolites were indeed formed by the NB4 cells in vitro. NB4 cell growth was inhibited (69-78% at 120 h) and cell cycle progression in the G1 phase (82-85% at 120 h) was blocked by ATRA and all of the metabolites at 1 microM concentration. ATRA and its metabolites could induce NB4 cells differentiation with similar activity, as evaluated by cell morphology, by the nitroblue tetrazolium reduction test (82-88% at 120 h) or by the expression of the maturation specific cell surface marker CD11c. In addition, nuclear body reorganization to macropunctated structures, as well as the degradation of PML-RAR alpha, was found to be similar for ATRA and all of its metabolites. Comparison of the relative potency of the retinoids using the nitroblue tetrazolium reduction test showed effective concentrations required to differentiate 50% of cells in 72 h as follows: ATRA, 15.8 +/- 1.7 nM; 4-oxo-RA, 38.3 +/- 1.3 nM; 18-OH-RA, 55.5 +/- 1.8 nM; 4-OH-RA, 79.8 +/- 1.8 nM; and 5,6-epoxy-RA, 99.5 +/- 1.5 nM. The ATRA metabolites were found to exert their differentiation effects via the RAR alpha nuclear receptors, because the RAR alpha-specific antagonist BMS614 blocked metabolite-induced CD11c expression in NB4 cells. These data demonstrate that the principal ATRA Phase 1 metabolites can elicit leukemia cell growth inhibition and differentiation in vitro through the RAR alpha signaling pathway, and they suggest that these metabolites may play a role in ATRA antileukemic activity in vivo.     

维甲酸和桂皮酸诱导HL—60细胞分化的研究

目的 探讨维甲酸和桂皮酸联合对人早幼粒白血病细胞（HL－60）诱导分化作用。方法 用1μmol/L全反式维甲酸（ATRA）和2．5mmol/L桂皮酸单独和联合处理HL－60细胞后,观察细胞形态的改变,进行细胞增殖速度、硝基四氮唑蓝（NBT）还原反应、过氧化酶染色的测定。结果 ATRA和桂皮酸都能使HL－60细胞形态向成熟粒细胞转变,两者对HL－60细胞增殖都有明显抑制作用,都能使细胞的BNT还原反应显著增强（P＜0．01）。前者强于后者。过氧化酶染色两者均为弱阳性或阴性。两者联合作用能使分化作用增强,但未显示相加效应。结论 ATRA和桂皮酸都具有诱导HL－60细胞分化作用,前者优于后者,两者联合分化作用增强。     

Reversible effects of retinoic acid on glycosaminoglycan synthesis during differentiation of HL-60 leukemia cells

Glycosaminoglycans (GAGs) play an important role in cell-cell and cell-substratum interactions, and undergo specific changes during neutrophil development. Previous studies (Luikart, S.D., Maniglia, C. A., and Sartorelli, A. C. Cancer Res., 44: 2907-2912, 1984) have shown that both dimethyl sulfoxide and 4-beta-phorbol-12-beta-myristate-13-alpha-acetate decreased GAG production by a hypoxanthine-guanine phosphoribosyl transferase-deficient clone of HL-60 promyelocytic leukemia cells prior to the appearance of a mature myeloid or monocytoid phenotype. To expand these investigations further, GAGs were analyzed by cetylpyridinium chloride precipitation and DEAE-Sephacel ion-exchange chromatography after labeling of parental HL-60 cultures with [35S]sulfate and D-[3H]glucosamine for 6 h, following treatment with 1 microM all-trans retinoic acid (RA). Chondroitin sulfate represented the major GAG species produced, although endo-beta-galactosidase-sensitive undersulfated macromolecules which possibly might be keratan sulfate, were also identified. GAG production decreased over a time period of 144 h in culture. RA treatment reduced the amount of radiolabeled cell-associated GAGs by 50% after 48, 96, and 144 h of exposure. In contrast, commitment to myelocytic maturation of the majority (i.e., approximately 60%) of the cells occurred between 72 and 96 h of RA treatment. Concurrently with the appearance of mature granulocytic cells, two-thirds of the radiolabeled GAGs were recovered from the medium, compared to one-third in untreated cultures, a phenomenon that resulted in an overall alteration in the distribution of GAGs. When RA was removed by washing after either 48 h (i.e., precommitment to differentiation) or 96 h (i.e., postcommitment to differentiation), a 1.5- to 3.5-fold increase in GAG production was noted 48 h later; this increase was unrelated to the medium change or to alterations in cell cycle distribution. The amounts of endo-beta-galactosidase-sensitive macromolecules were unaltered. Thus, although 1 microM RA inhibited the synthesis of chondroitin sulfate by HL-60 leukemia cells, this inhibition was reversible by removal of the drug and appeared to be unrelated to the commitment to myelocytic maturation.     

桂皮酸联合维生素C对HL-60的细胞诱导分化

目的　探讨桂皮酸和维生素C(V C)对人早幼粒白血病细胞 (HL 6 0 )的分化作用。方法　用2 .5mmol L桂皮酸和 0 .5mmol LV C单独和联合处理HL 6 0细胞后 ,观察细胞形态改变 ,测定细胞增殖速度、硝基四氮唑蓝 (NBT)还原反应、过氧化酶染色反应。结果　两者都能使HL 6 0细胞形态向成熟粒细胞转变 ,对细胞增殖有明显抑制作用 ,前者强后者弱 ;桂皮酸使细胞的NBT反应显著增强 (P <0 .0 1) ,过氧化酶染色为弱阳性或阴性 ;V C使NBT反应和染色反应改变不明显 (P <0 .0 5 ) ,两者联合作用 ,分化作用增强。结论　桂皮酸有很强诱导HL 6 0细胞分化的作用 ,v c的分化作用不明显 ,但有增强桂皮酸分化的作用。     

Variable regulation of sensitivity to retinoic acid-induced differentiation in wild-type and retinoic acid-resistant HL-60 cells

The initial cell association and metabolic conversion of retinoic acid (RA) by HL-60 cells in serum-free, transferrin/insulin-supplemented, RPMI 1640 medium was greater than or equal to 10-fold greater than in RPMI 1640 medium containing 10% fetal bovine serum (FBS). This was paralleled under the serum-free conditions by 10-fold greater sensitivity to RA-induced differentiation, which was partially reversed by the addition of purified bovine serum albumin to the same concentration present in 10% FBS. In serum-free HL-1 medium, HL-60 cell sensitivity to RA-induced differentiation was approximately 250-fold less than in serum-free RPMI 1640 medium but, in this comparison, there was little difference in RA cell association or metabolism. A greater than 200-fold RA-resistant HL-60 subline had RA cell-association and metabolism rates similar to those of wild-type cells under all culture conditions. No significant qualitative differences in the high performance liquid chromatography elution patterns of polar metabolites were observed under any circumstances. These results indicate that inherent cellular properties, not associated with gross differences in RA uptake or metabolism, primarily determined the relative sensitivity or insensitivity of HL-60 cells to RA-induced differentiation but that RA responsiveness was markedly regulated by extracellular factors, one of which, serum albumin, appeared to act by decreasing the initial cell association and metabolism of RA, whereas other, as yet unidentified exogenous factors, may have acted independently of these functions.     

Membrane glycoprotein changes associated with anthracycline resistance in HL-60 cells

Summary The glycoproteins on the surface of HL-60/S wild-type, drug-sensitive human leukemia cells and HL-60/AR anthracycline-resistant cells which do not overexpress the P-glycoprotein, were characterized by labeling with [³⁵S]-methionine, NaB[³H₄], phosphorus 32, or sodium iodide I 125. HL-60/S and HL-60/AR cell lysates and membrane fractions tagged with [³⁵S]-methionine or phosphorus 32 showed no significant differences in their protein patterns as analyzed by sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) and by autoradiography. HL-60/S cells labeled with NaB[³H₄] yielded glycoproteins that were smeared predominantly in the molecular-weight range of 210,000 and 160,000 Da, with pI values ranging between pH 4 and pH 4.4. In contrast, NaB[³H₄]-labeled HL-60/AR cells showed 7–8 discrete glycoproteins within a molecular-weight range of 170,000 and 140,000 Da, with pI values also ranging between pH 4 and pH 4.4. In addition, [³H]-glucosamine incorporation into HL-60/S and HL-60/AR cells revealed that the latter showed lower uptake of [³H]-glucosamine than did the former. Following treatment with tunicamycin, [³H]-glucosamine uptake in HL-60/S cells decreased, whereas that in HL-60/AR cells remained unchanged. Surface-membrane radioiodination of HL-60/S and HL-60/AR cells showed two distinct protein electrophoretic patterns, with differences being observed in both the high-(220–95 kDa) and low-molecular-weight ranges (21 kDa). Flow cytometric analysis of HL-60/S and HL-60/AR cells using myeloid and lymphoid antigen-specific antibodies demonstrated no antigenic differences between HL-60/S and HL-60/AR cells. HL-60/S cells incubated in the presence of tunicamycin, an inhibitor ofN-linked glycosylation, or the protein kinase C agonist phorbol 12-myristate 13-acetate (PMA) developed a glycoprotein pattern similar to that observed in HL-60/AR cells. In addition, tunicamycin treatment of HL-60/S cells decreased daunorubicin (DNR) retention and altered its intracellular distribution as compared with that in HL-60/AR cells. These data indicate that HL-60/AR cells do not possess either de novo or amplified high-molecular-weight surface-membrane proteins; instead, existing proteins are hypoglycosylated. These results also show that HL-60/AR cells exhibit the multidrug-resistant phenotype in association with altered membrane glycoproteins of both high (220–95 kDa) and low molecular weight (21 kDa), but without overexpression of the P-glycoprotein. Furthermore, in HL-60/S cells, the multidrug-resistant phenotype is partially inducible by inhibition ofN-linked glycosylation of cell-surfac proteins.Abbreviations HL-60/AR anthracycline-resistant cells - HL-60/S parental HL-60 cells - DNR daunorubicin - RA retinoic acid - PBS phosphatebuffered saline (Hanks' Balanced Salt Solution) - PMA phorbol 12-myristate, 13-acetate - DVFM digitized video fluorescence microscopy - DFP diisopropylfluorophosphate - SDS-PAGE sodium dodecyl sulfatepolyacrylamide gel electrophoresis - MDR multidrug resistance - 6GT 6-thioguanine - NP-40 Nonidet-40 detergent Supported by grants ACS CH-357, CA-31 761, CA-42 450, CA-40 188, the, William J. Matheson Foundation, the Medical Research Council of Canada, and the National Cancer Institute of Canada     

Specific cytoskeleton changes during apoptosis accompanying induced differentiation of HL-60 myeloid leukemia cells

Changes in actin filaments and microtubules were studied in the human myeloid leukemia HL-60 cell line during the process of apoptotic cell death accompanying induced differentiation. These cytoskeleton changes were assessed during a 6-day cultivation in the presence of 10(-6) M all-trans retinoic acid (ATRA), a specific inductor of both differentiation into granulocytes and apoptosis, or during a 18-day cultivation in the presence of 1.6 nM phorbol myristylacetate (PMA), which induces differentiation into macrophages. The processes were studied at the morphological level by fluorescence microscopy and, quantitatively, by flow cytometry. The results showed that the actin cytoskeleton underwent specific structural changes during the apoptotic process, but microtubules were not actively involved. In the initial stages of apoptosis, a fine meshwork of actin filaments turned into actin granules that, in the final stages, were transformed into a network of long actin fibres distributed throughout the cytoplasm. These actin structures were considered to play an active role in two main morphological events of apoptosis - formation of blebs and final cell disintegration into apoptotic bodies. In addition, high proportion of cells with apoptotic nuclei and completely destroyed actin structures were found in the differentiating ATRA-treated cell population. Flow cytometric measurement of cytoskeletal proteins content confirmed all these observed changes. Alterations and rearrangements of both cytoskeletal structures are common for the apoptotic cell death of HL-60 cells and they are independent on the course of differentiation.     

Induction of differentiation in HL-60 cells by retinoic acid and lymphocyte-derived differentiation-inducing factor but not by recombinant G-CSF and GM-CSF

Various concentrations of retinoic acid (RA, 10⁻⁹ to 10⁻⁷ M), lymphocyte-derived differentiation-inducing factor (DIF, 10–30%), and recombinant human G-CSF (100–4000 U/ml) and GM-CSF (100–4000 U/ml) were used to induce the differentiation of the HL-60 promyelocytic leukemia cells. Retinoic acid at a concentration of 10⁻⁷M could significantly inhibit the growth of HL-60 cells both in suspension and in soft agar cultures, and induced these cells to differentiate into mature granulocytes capable of reducing nitro-blue tetrazolium and ingesting latex beads. Thirty per cent (v/v) DIF was also an effective inducer of HL-60 cell differentiation, but it triggered the cells to mature into monocytes rather than granulocytes. In contrast, rG-CSF and rGM-CSF had no growth inhibitory effect on HL-60 cells either in suspension or in agar cultures at all concentrations tested, nor could these factors induce HL-60 cells to acquire the more mature granulocytic or monocytic phenotypes. Furthermore, rG-CSF/rGM-CSF had no differentiation-enhancing effect when added to RA-containing HL-60 cultures. These results argue against the efficacy of using CSFs for the treatment of myelocytic leukemia based on the principle of differentiation induction.     

Alternative differentiation of human promyelocytic leukemia cells (HL-60) induced selectively by retinoic acid and 1 alpha,25-dihydroxyvitamin D3

Induction of hematopoietic differentiation was investigated in human promyelocytic leukemia cells [HL-60] using two lipophilic vitamins, retinoic acid and 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3]. Both vitamins suppressed proliferation and induced differentiation of HL-60 cells, but 1 alpha,25(OH)2D3 was 70- to 100-fold more potent than was retinoic acid on a molar basis. Simultaneous treatment with suboptimal concentrations of 1 alpha,25(OH)2D3 (0.12 to 1.2 nM) and retinoic acid (10 to 100 nM) showed additive effects in reducing nitroblue tetrazolium, a common marker for monocyte-macrophage and granulocyte differentiation. For the study of alternative differentiation of the cells by the two vitamins, we used monoclonal antibodies specific for either human monocyte-macrophages or granulocytes and other markers specific for macrophage differentiation such as alpha-naphthyl acetate esterase activity and adherence to the dish surface. HL-60 cells were induced to differentiate alternatively into macrophages by 1 alpha,25(OH)2D3 or into granulocytes by retinoic acid. When HL-60 cells were treated with various concentrations of 1 alpha,25(OH)2D3 (1.2 to 120 nM) in the presence of 1000 nM retinoic acid which is a concentration sufficient to induce maximal granulocyte differentiation, the appearance of the markers for monocyte-macrophage differentiation by 1 alpha,25(OH)2D3 was not at all affected by the retinoic acid. These results indicate that 1 alpha,25(OH)2D3 and retinoic acid have additive effects in inducing differentiation of HL-60 cells, but monocyte-macrophage differentiation by 1 alpha,25(OH)2D3 occurs much more readily than does granulocyte differentiation by retinoic acid.     

全反式维甲酸对HL-60细胞hTERT基因表达和端粒酶活性的影响

目的 探讨全反式维甲(ATRA)诱导HL-60细胞分化过程中人类端粒酶逆转录酶(hTERT)蛋白表达和端粒酶活性的改变。 方法 应用间接免疫荧光标记法通过流式细胞仪检测hTERT蛋白含量的变化;采用多聚酶链反应-酶联免疫反应(PCR-ELISA)方法检测ATRA处理HL-60细胞前后端粒酶活性的改变,用碘化丙锭染色经流式细胞仪检测细胞周期变化。 结果 1μmol/L ATRA作用HL-60细胞24、48、72h,hTERT蛋白平均荧光强度分别为61.87±4.36、37.47±2.85、33.45±2.37,与空白对照组相比,具有显著性差异,P<0.05。1μmol/L ATRA作用48h后,HL-60细胞的端粒酶活性即出现下降,作用72h,端粒酶的活性明显受到抑制。 结论 在HL-60细胞分化过程中,ATRA能抑制HL60细胞的hTERT基因的表达和端粒酶活性。     

Fatty acid composition of HL-60 cells is modified upon proliferation arrest and differentiation

The human leukemic cell line HL-60 undergoes differentiation to granulocytic-like cells in response to dimethyl sulfoxide (DMSO) or retinoic acid (RA). This differentiation is accompanied by an arrest in cell proliferation. Studies have implicated alterations in the phospholipid fatty acid (FA) composition as a result of HL-60 differentiation. However, changes in FA's are also known to occur during the arrest of cellular proliferation. Using a highly efficient capillary gas-liquid chromatography technique, the phospholipid FA composition of HL-60 and of DMSO-resistant and RA-resistant HL-60 subclones was determined in proliferating cells, in density-arrested cells, and in terminally differentiated cells. The same specific modifications in some of the FAs of the three cell lines were observed when proliferation was inhibited by cell density; 16:0 and 18:2n-6 were decreased and 22:6n-3 increased. Moreover, 16 and 18 dimetylacetals were both increased when proliferation was decreased, indicating modifications in plasmalogen contents. Granulocytic differentiation of HL-60 cells and of its subclones with DMSO and/or RA provoked modifications in phospholipid FAs different from that found in density-arrested, undifferentiated cells such as decreases in monoenoic FAs of 16 and 18 carbons as well as an increase in arachidonic acid, the major polyunsaturated FA. The biological significance of these changes upon arrest of proliferation and differentiation are discussed. These results indicate that, when arrest of proliferation accompanies differentiation, these two phenomena can be responsible for different changes and, whenever possible, they have to be considered separately in order to know which modifications are effectively due to differentiation itself.     

Induction of differentiation by tumour necrosis factor in HL-60 cells is associated with the formation of large DNA fragments

The DNA fragmentation induced by tumor necrosis factor (TNF) of differentiable human myeloid leukemic HL-60 cells has been further characterized. TNF increased the appearance of very high molecular weight DNA fragments detected by agarose gel electrophoresis. The use of pulsed-field gel electrophoresis (PFGE) revealed these fragments to be as high as 200-400 kilobase pairs. The pattern of HL-60 DNA fragmentation contrasted with that of U937 cells, which exhibited lower molecular weight, nucleosome multiple sized fragments, and greater cytotoxicity in response to TNF. The peak increase of fragments from HL-60 occurred between one and two hours of incubation, with TNF concentrations of 10 U/ml or higher, and was inhibitable by 1 mM Zn2+. Southern blotting of these fragments disclosed enrichment for c-myc related sequences compared with control probes including beta-actin and kappa and lambda light chains. Treatment of DNA with NotI or gamma-irradiation, followed by PFGE, disclosed a class of still higher molecular weight DNA, which decreased following TNF treatment, and which was apparently the precursor of the TNF-induced fragments. TNF thus rapidly increases a class of high molecular weight DNA fragments which are enriched for c-myc related sequences and may arise preferentially from higher molecular weight structures which are detectable following linearization by NotI or gamma-irradiation. Such major but non-random alterations in chromatin structure may contribute to TNF-induced monocytoid differentiation of HL-60.     

Crocidolite asbestos suppresses the differentiation of HL-60 cells induced by DMSO.

This study was undertaken to determine if the biological function of inducers for cell differentiation is affected by asbestos fibers, which are sometimes deposited in human tissues. Protein kinase C activity, c-myc protein expression and cell surface CR3 expression were used as the markers of cell differentiation. The function of dimethylsulfoxide (DMSO), an inducer of cell differentiation, was suppressed by the co-culturing of crocidolite asbestos, because DMSO reacted with the hydroxyl radical released after the stimulation with crocidolite and spent itself. Superoxide dismutase (SOD) inhibited the effect of crocidolite, reacting rapidly with .O2- before the secondary release of .OH. Asbestos fibers deposited in tissues may inhibit the function of inducers which stimulate immature cells to differentiate, because such inducers frequently are also radical scavengers.     

冬凌草甲素联合丙戊酸钠对HL-60细胞的生长抑制和诱导凋亡作用研究

目的 研究中药单体冬凌草甲素(ORI)联合组蛋白去乙酰化酶抑制剂丙戊酸钠(VPA)诱导急性早幼粒白血病细胞株HL-60凋亡,探讨其应用于临床的可行性.方法 在对数生长期的HL-60细胞中分别加入6～12 la,mol/L的ORI和0.5~1 mmol/L的VPA,采用细胞计数法测定ORI和VPA单独和联合应用时对细胞的...     

HL-60 cell differentiation induced by phorbol- and 12-deoxyphorbol-esters

The haman promyelocytlc leukaemia cell (HL-60) under goes differentiationinto a macrophage-like form when exposed to both tumour promoting-and non-promoting phorbol esters. We have Investigated the effectof the two non-promoting phorbol esters, 12-deoxyphorbol-13-O-phenylacetate(Dopp) and 12-deoxyphorbol-13-O-phenyl-acetate-20-acetate (Doppa)on HL-60 cultures, and compared them with the twnour promoter12-O-tetradecanoylphor-bol-13-acetate (TPA). All phorbol esterstested were found to be able to stop HL-60 proliferation andinduce cell adherence and morphological changes characteristicof differentiation. TPA, fully differentiating at 1 nM, wasmore potent than Dopp and Doppa, which required 100 nM for fulldifferentiation effects within the 4 day study. Doppa initiallyappeared weaker than Dopp at inhibiting incorporation of thymidine,the earliest effect studied, but we were able to detect rapidC-20 deacylation of Doppa, converting It to Dopp, using an HPLCprotocol presented here. A detailed study of this thymidineIncorporation Inhibition showed that both TPA (10 nM or greater)and Dopp (500 nM or greater) have very similar time courses,wIth 50% inhibition occurring at     

雷公藤多甙诱导HL-60细胞凋亡

目的：探讨雷公藤多甙对ＨＬ－６０细胞凋亡的作用。方法：应用细胞形态学检查,ＤＮＡ凝胶电泳及流式细胞仪分析检测。结果：ＨＬ－６０细胞加上雷公藤多甙１０ｍｇ／Ｌ孵育７２ｈ,流式细胞仪检测细胞凋亡率为２９．４％（与空白对照组比较,Ｐ〈０．０１）。电检查和光镜检查均可见细胞核固缩、碎裂等。ＤＮＡ电泳显示明显的梯状条带。结论：雷公藤多甙能诱导ＨＬ－６０细胞凋亡,提示雷公藤多甙可能具有抗白血病作用。     

Changes in thymidine kinase activity during differentiation of HL-60 leukemic cells

Induction of granulocyte maturation in HL-60 leukemic cells by DMSO (1.2%) or RA (1 microM) is accompanied by a 50-60% decrease in cellular thymidine kinase activity. Similarly, the differentiation of HL-60 cells into monocyte-macrophage phenotype by the addition of PMA is paralleled by a 60-80% suppression of thymidine kinase specific activity. Measurement of thymidine kinase kinetic parameters shows that the Vmax decreases from 0.7 pmol/min in control cells to 0.43 pmol/min in PMA-treated cells and to 0.38 pmol/min in RA-treated cells. The Km of the enzyme is not affected by either inducing agent and remains at 2.1 microM. Studies with PMA analogs suggest that thymidine kinase modulation is coupled to HL-60 differentiation.     

蟾蜍灵联合ATRA诱导HL-60细胞分化并上调Syk表达

目的:观察低剂量蟾蜍灵、全反式维甲酸(All-trans retinoic acid,ATRA)单药或联合应用对HL-60细胞增殖及分化的影响,同时检测上游通路Syk表达的变化.方法:流式细胞仪技术检测CD11b表达;Western Blot检测Syk和Tubulin表达.结果:与对照组相比,低剂量蟾蜍灵、ATRA或联合用药不同程度地抑制HL-60细胞增殖,同时蟾蜍灵联合ATRA以时间依赖性的方式诱导HL-60细胞分化,并伴有Syk表达上调,但是Syk的酪氨酸磷酸化并未受影响.结论:Syk表达上调可能参与调节低剂量蟾蜍灵联合ATRA对HL-60细胞的分化诱导作用.     

All-trans retinoic acid induced the differentiation of human glioma cells

Objective  

To observe the effect of all-trans retinoic acid (ATRA) on inducing human glioma MO59K cells differentiation and further explore the underlying molecular mechanisms.