两种分化诱导剂对HL－60细胞诱导分化过程中酪氨酸蛋白磷酸化作用的影响

研究了两种诱导分化剂星状孢子素（ｓｔａｕｒｏｓｐｏｒｉｎｅ）及金雀异黄素（ｇｅｎｉｓｔｅｉｎ）在诱导人早幼粒白血病细胞（ＨＬ－６０细胞）的过程中酪氨酸蛋白激酶（ＴＰＫ）及酪氨酸蛋白磷酸酶（ＰＴＰＰ）的活力变化。结果表明，两种分化诱导剂对胞浆及膜两部分的ＴＰＫ活力均有不同程度的抑制，而对这两部分的ＰＴＰＰ活力则有不同程度的激活作用，说明分化诱导剂可使ＨＬ－６０细胞内的酪氨酸的磷酸化水平提高，揭示了诱导分化与酪氨酸磷酸化及脱磷酸化之间的关系，为寻找新的抗癌药物提供了帮助。     

Ultrastructural peroxidase cytochemistry of three established human myelogenous leukemia cell lines, HL-60, KG-1 and ML-2

We studied the ultrastructural peroxidase cytochemistry of three established human acute myelogenous leukemia cell lines (HL-60, KG-1 and ML-2) to clarify the cytochemical differences and the differences in maturation/differentiation stages. HL-60 cells contained azurophil granules which exhibited strong peroxidase reaction. The more central region of individual granules is less reactive than the outer portion of these granules. The secretory apparatus of HL-60 cells, i.e. rough endoplasmic reticulum, perinuclear cisterna and Golgi apparatus, also contained peroxidase-reactive material. ML-2 cells contained azurophil granules with peroxidase reaction; however, nuclear membranes were peroxidase-negative and thin cisternae of rough endoplasmic reticulum exhibited only a faint peroxidase reaction. KG-1 cells were peroxidase-negative. From these findings KG-1 is classified as the least mature of the cell lines studied. ML-2 cells are considered early promyelocytes and HL-60 cells as late promyelocytes.     

Induction of erythroid differentiation of K562 human leukemic cells by herbimycin A, an inhibitor of tyrosine kinase activity

Herbimycin A, a benzoquinonoid ansamycin antibiotic, is found to reduce intracellular phosphorylation by tyrosine protein kinase. The human chronic myelogenous leukemia cell line K562 expresses a structurally altered c-abl protein with tyrosine kinase activity. When K562 cells are induced to undergo erythroid differentiation by hemin, reduction in the intracellular level of tyrosine phosphorylation occurs. In order to understand the relationship between induction of differentiation and reduction of tyrosine phosphorylation by the c-abl gene product, the effect that herbimycin A, a selective inhibitor of intracellular tyrosine kinase activity, exerts on the differentiation of K562 cells was examined. Reduction of tyrosine phosphorylation in K562 cells by herbimycin A was observed within 1 h. Noncytotoxic concentrations of herbimycin A induced erythroid differentiation of K562 cells but not of murine erythroleukemia 745A cells. The other human myeloid leukemia cell lines (HL-60, THP-1, and U937) tested were not induced to undergo cell differentiation by this antibiotic. Herbimycin A and the other well-known inducers such as hemin, butyric acid, Adriamycin, and 1-beta-D-arabinofuranosylcytosine had additive or more than additive effects on induction of erythroid differentiation of K562 cells. With respect to inhibition of cell growth, the sensitivity of K562 cells to herbimycin A was highest in the human leukemia cell lines we tested. Noncytotoxic concentrations of herbimycin enhanced the antiproliferative effect of Adriamycin or 1-beta-D-arabinofuranosylcytosine on K562 cells. Combination therapy with herbimycin A and its derivatives may be considered for use in the treatment of some types of leukemia where tyrosine kinase activities are implicated as determinants of the oncogenic state.     

Cotylenin A-induced differentiation is independent of the transforming growth factor-beta signaling system in human myeloid leukemia HL-60 cells

Cotylenin A, which has been isolated as a plant growth regulator, potently induces the differentiation of human myeloid leukemia cells. Treatment of HL-60 cells with a combination of transforming growth factor (TGF)-beta and 1alpha, 25-dihydroxyvitamin D(3) (VD3) resulted in increased differentiation compared to separate treatments, but TGF-beta did not affect the cotylenin A-induced differentiation of HL-60 cells. It is possible that the signal transduction pathway used by cotylenin A for inducing the differentiation of leukemia cells is the same as that used by TGF-beta. However, cotylenin A did not affect the expression of TGF superfamily or Smad genes in HL-60 cells. Treatment with neutralizing anti-TGF-beta antibody or an inhibitor of TGF-beta signaling did not inhibit cotylenin A-induced differentiation, although VD3-induced differentiation was significantly suppressed by these treatments. The subcellular distribution of Smad3 was also unaffected by cotylenin A. These results suggest that the cotylenin A-induced differentiation of leukemia cells is independent of the TGF-beta signaling system, although TGF-beta acts as an autocrine mediator of the growth arrest and differentiation of leukemia cells induced by VD3 and other inducers.     

Myeloid and monocytoid leukemia cells have different sensitivity to differentiation-inducing activity of deoxyadenosine analogs

The differentiation-inducing effect of clinically applicable analogs of deoxyadenosine on myelomonocytic leukemia cells was examined. Monocytoid leukemia cells were more sensitive to the analogs than were erythroid or myeloid leukemia cells based on the inhibition of cell growth and induction of cell differentiation. Monocytoid leukemia cells were highly sensitive to combined treatment with 2'-deoxycoformycin (dCF) and 9-beta-D-arabinofuranosyladenine (Ara A) for inducing cell differentiation. Ara A induced the differentiation of monocytoid leukemia U937 and THP-1 cells at concentrations which were 1/1000-10000 of that at which it induced the differentiation of other cell lines in the presence of dCF. In combination with a low concentration of 1alpha,25-dihydroxyvitamin D3 (VD3), the induction of the monocytic differentiation was greater in monoblastic U937 cells. Adenosine deaminase-resistant analogs such as fludarabine (FLU) and cladribine (CdA) also induced the differentiation of human myelomonocytic leukemia cells, and these analogs synergistically enhanced the differentiation induced by all-trans retinoic acid (ATRA) or VD3. CdA was the most potent analog for inducing the differentiation of myeloid leukemia NB4 and HL-60 cells in the presence or absence of ATRA. These findings indicate that dCF + Ara A and CdA may be effective for the therapy of acute monocytoid and myeloid leukemia, respectively.     

Changes in cell surface glycoproteins and antigens during differentiation of the human myeloid leukemia cell lines ML-1, ML-2, and HL-60

Two recently derived human myeloid leukemia cell lines, ML-1 and ML-2, were induced to differentiate by treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) or with retinoic acid for 5 to 12 days. They were then compared with similarly treated promyelocytic HL-60 cells. TPA-treated ML-1 and ML-2 cells became firmly surface adhesive with a fibroblastoid morphology, while TPA-treated HL-60 cells adhered as rounded macrophages. In contrast, retinoic acid induced only slight morphological changes in all three cell lines. The differentiation-related alterations of the surface membrane glycoproteins were followed by polyacrylamide gel electrophoresis after surface labeling by the periodate-NaB3H4 or galactose oxidase-NaB3H4 methods. The expression of surface membrane differentiation antigens was analyzed with a panel of monoclonal antibodies against myeloid, myelomonocytic, monocytic, and granulocytic determinants using FACS IV flow cytometry. The acquisition of surface adhesiveness by TPA-treated ML-1 and ML-2 cells coincided with the appearance of membrane surface proteins of varying molecular weights, ranging between 90,000 and 155,000, which were not labeled in untreated ML-1 and ML-2 cells. These findings and the results obtained by monoclonal antibody staining and FACS analysis indicate that treatment of the myeloid lines ML-1, ML-2, and HL-60 by TPA induced the expression of antigenic and membrane molecular features compatible with a monocytic-macrophage phenotype, while treatment by retinoic acid induced granulocytic differentiation. The ML-1 and ML-2 cells offer interesting models for studies on the membrane molecular events occurring when nonadherent, monocytic cells become surface adherent.     

KN-62 analogues as potent differentiating agents of HL-60 cells

KN-62, an inhibitor of the calmodulin-dependent protein kinases (CaMKs), enhances the terminal differentiation of retinoic acid sensitive human myeloid leukemia cell lines. In an effort to identify additional CaMK inhibitors that exhibit more potent activity in triggering leukemia cell differentiation, we synthesized 45 analogues of KN-62 and determined their ability to induce HL-60 cell differentiation. Sixteen of these novel analogues exhibited significant differentiation-inducing activity, and one analogue, AS-004, was five times more potent than KN-62 in inhibiting proliferation and inducing differentiation of HL-60 cells. Such KN-62 analogues and/or related compounds may prove useful in treating promyelocytic leukemia.     

Modulation of retinoic acid-induced differentiation of human leukemia (HL-60) cells by serum factors and sphinganine

The human cell line HL-60 was used to investigate the role of protein kinase C in the regulation of retinoic acid-induced maturation of promyelocytic leukemia cells by growth and differentiation factors found in serum. Cells grown in serum-containing medium differentiated less than cells in serum-free medium due to several factors, including albumin binding of retinoic acid. Addition of an inhibitor (sphinganine) of protein kinase C, an enzyme that participates in cellular responses to many serum factors, facilitated the retinoic acid-induced differentiation. Cells treated with both retinoic acid and sphinganine produced more superoxide when stimulated by formylmethionylleucylphenylalanine; hence, this combination generated a more functional population of cells. The ability of sphinganine to promote retinoic acid-induced differentiation suggests that retinoic acid therapy might be improved by the concurrent use of a modulator of protein kinase C activity.     

Expression of tyrosine kinases encoding protooncogenes in differentiating human leukemia-cells

We investigated the expression of the tyrosine kinase encoding proto-oncogenes c-src and fyn during in vitro differentiation of the human promyelocytic leukemia cell line HL-60 and an HL-60 derived cell line (HL-GOT) with an altered T-cell receptor gene. In HL-60 cells, the fyn and c-src encoded tyrosine kinases are activated in a differentiation-dependent manner, whereas in HL-60T cells high levels of pp59(fyn) and pp60(c-src) specific kinase activities are already present in the untreated cells. From the data obtained we conclude that untreated HL-60T cells represent a more differentiated type of cells compared to the untreated promyelocytic HL-60 cells.     

Effects of transforming growth factor-beta and activin A on vitamin D3-induced monocytic differentiation of myeloid leukemia cells

We examined the effects of transforming growth factors beta(TGF-beta) alone and in combination with 1 alpha,25-dihydroxyvitamin D3 (VD3) on human leukemic cell lines (HEL/S, HL-60 and K562). TGF-beta 1 alone at higher concentrations induced monocytic differentiation of HEL/S cells. Combinations of TGF-beta 1 and VD3 synergistically inhibited cell proliferation and induced monocytic differentiation of HEL/S and HL-60 cells. TGF-beta 2 (a subtype of TGF-beta) and erythroid differentiation factor (EDF/Activin A, a member of the TGF-beta gene family) also inhibited growth and induced monocytic differentiation of HL-60 cells in synergy with VD3. Thus combinations of VD3 and TGF-beta (TGF-beta 1, -beta 2, or EDF) acted synergistically in inhibiting cell proliferation and inducing monocytic differentiation of human leukemia cells.     

Alterations in tyrosine phosphorylation during the granulocytic maturation of HL-60 leukemia cells

Granulocytic maturation of HL-60 promyelocytic leukemia cells induced by dimethylsulfoxide has been shown to produce a decrease in cellular protein phosphotyrosine residues and increases in both tyrosine kinase and protein phosphotyrosine phosphatase activities (D. A. Frank and A. C. Sartorelli, Biochem. Biophys. Res. Commun., 140: 440-447, 1986). These changes have been shown to not be restricted to dimethylsulfoxide-induced differentiation, since similar changes occur in HL-60 cells initiated with retinoic acid and in HL-60 sublines resistant to dimethylsulfoxide-induced differentiation treated with the retinoid. These regulatory events are not directly coupled to growth arrest, which accompanies terminal maturation, since the anthracycline antibiotics aclacinomycin A and marcellomycin, which induce HL-60 differentiation, cause these changes in phosphotyrosine metabolism, while Adriamycin, at a level which produces an equivalent degree of growth inhibition but does not initiate the maturation of HL-60 cells, does not. Furthermore, an HL-60 subline deficient in hypoxanthine-guanine phosphoribosyltransferase, which differentiates in the presence of 6-thioguanine, produced a decrease in phosphotyrosine residues and increases in tyrosine kinase and phosphotyrosine phosphatase activities in response to the purine antimetabolite, while the parental HL-60 line, in which 6-thioguanine inhibits cellular proliferation but does not induce maturation, does not exhibit these changes. Finally, similar alterations in phosphotyrosine regulation were exhibited during anthracycline-induced differentiation of the murine myelomonocytic leukemia cell line WEHI-3B D+, supporting the concept that the phenomena measured represent a general response to inducers of the granulocytic differentiation of leukemia cells.     

Cellular retinoid-binding proteins in cultured human and mouse myeloid leukemia cells

Retinoic acid and retinol induced functional and morphological differentiation of human promyelocytic leukemia cells (HL-60) into mature granulocytes, but did not induce functional or morphological differentiation of mouse myeloid leukemia cells (M1). Cellular retinoic acid-binding protein, but not retinol-binding protein, was detected on HL-60 cells. Neither binding protein could be detected on M1 cells. These results suggest that retinoic acid-binding protein may be necessary for induction by retinoids of functional and morphological differentiation of myeloid leukemia cells.     

Myeloid differentiation associated tyrosine protein kinase activity in WEHI-3B murine monomyelocytic leukemia cells.

Tyrosine protein kinase activity was examined during the induction of granulocytic differentiation of WEHI-3B murine monomyelocytic leukemia cells by retinoic acid and aclacinomycin A. Tyrosine kinase activity was found to increase throughout the period of induced maturation. The specificity of this increase in enzymatic activity for the differentiated state was demonstrated by the findings that (a) it was independent of the inducer used, and (b) the treatment of a differentiation-resistant subline of this murine leukemia with an inducer did not produce a significant elevation of tyrosine kinase activity. To determine whether tyrosine protein kinase activity was involved in the differentiation process itself or whether it was a product of the mature state, a series of experimental approaches was employed. Kinetic analyses showed that tyrosine protein kinase activity continued to increase beyond the peak in the level of differentiation. In addition, the total cellular protein phosphotyrosine content, measured by immunoblotting and flow cytometric analysis with anti-phosphotyrosine antibodies, did not increase in accord with the elevation of tyrosine kinase activity. Increases in protein phosphotyrosine content, which were dependent upon the length of exposure to the inducing agent, were observed when cultured cells were treated with the phosphotyrosine phosphatase inhibitor, sodium orthovanadate. Thus, the effect of the increasing tyrosine kinase activity in maturing cells appeared to be negated by competing protein phosphotyrosine phosphatase activity. Finally, the inhibitors of tyrosine kinase activity, genistein and PKI-23, did not interfere with the induction of differentiation by retinoic acid. These findings support the concept that myeloid differentiation associated tyrosine protein kinase activity may not be involved in the initiation of the differentiation process itself. This conclusion deviates from previous assumptions, based on earlier work in this laboratory as well as in that of others, that the differentiation associated kinase activity has an essential role in the initiation of the maturation process. An attractive alternative speculation is that this activity may have a functional role in the mature myeloid cell.     

Synergistic effects of clinically achievable concentrations of 12-O-tetradecanoylphorbol-13-acetate in combination with all-trans retinoic acid, 1alpha,25-dihydroxyvitamin D3, and sodium butyrate on differentiation in HL-60 cells.

Our recent studies demonstrated that 12-O-tetradecanoylphorbol-13-acetate (TPA) has pharmacological activity for the treatment of acute myelocytic leukemia patients. In the present study, we investigated the potential synergistic effect of all-trans retinoic acid (RA), 1alpha,25-dihydroxyvitamin D3 (VD3), and sodium butyrate (NaB) on TPA-induced differentiation in HL-60 human promyelocytic leukemia cells. The cells were treated once with these agents for 48 h or treated every 24 h for 96 h. Treatment of HL-60 cells once with TPA, RA, VD3, or NaB for 48 h resulted in concentration-dependent growth inhibition and cell differentiation. At clinically achievable concentrations, TPA (0.16 nM) increased the number of adherent cells and RA (0.1-1 microM) increased the number of nitroblue tetrazolium (NBT)-positive cells. The combinations of TPA (0.16 nM) with RA (0.1-1 microM), VD3 (1 nM), or NaB (100 microM) for 48 h synergistically increased differentiation as measured by the formation of adherent cells (P < or = 0.01). Moreover, cells treated with various combinations of low concentrations of TPA, RA, VD3, and NaB every 24 h for 96 h resulted in a further decrease in cell growth and an increase in differentiation. At clinically achievable concentrations, the strongest stimulation of differentiation was achieved in cells treated with a "cocktail" that combined TPA, RA, VD3, and NaB. The synergistic effect of combinations of TPA with RA or NaB at clinically effective concentrations on HL-60 cell differentiation suggests that the combination of these agents may improve the therapeutic efficacy of TPA for the treatment of acute promyelocytic leukemia (APL) patients. A differentiation "cocktail" that combines TPA, RA, VD3, and NaB may provide an even more effective strategy for improving the therapeutic efficacy of TPA and RA.     

Inhibition of proliferation and induction of differentiation of human myeloid leukemia cells by novel nucleoside analogs

Purines such as hypoxanthine and 6-thioguanine have the capacity to induce the differentiation of human myeloid leukemia HL-60 cells in culture. Several nucleoside analogs were synthesized and their effects on cell proliferation and differentiation of HL-60 cells were examined. On incubation with these compounds, proliferation of HL-60 cells was inhibited and the cells were induced to differentiate into morphologically and functionally mature granulocytes. Among the compounds we tested, 2,4-diethyl-7,7,8,8-tetramethyl-cis-2,4-diazabicyclol [4.2.0] octane-3,5-dione was the most effective in inducing differentiation of HL-60 cells. This compound was approximately 100 times more potent on a molar basis than hypoxanthine. The compounds reacted synergistically or additively with a typical antileukemic drug (daunomycin) or another potent differentiation inducer (retinoic acid).     

Inhibition of abl oncogene tyrosine kinase induces erythroid differentiation of human myelogenous leukemia K562 cells

The human chronic myelogenous leukemia cell line K562 expresses a structurally altered c-abl protein with tyrosine kinase activity. Erythroid differentiation of K562 cells was induced by tyrosine kinase inhibitors, but not by other kinase inhibitors. Treatment of K562 cells with 5'd(TACTGGCCGCTG-AAGGGC)3', complementary to the second exon (codons 2 to 7) of c-abl mRNA, inhibited cell growth and induced benzidine-positive cells in a dose-dependent manner. However, exposure to the sense oligomer did not induce erythroid differentiation of the cells. These results suggest that inhibition of abl tyrosine kinase activity is closely related to induction of erythroid differentiation of K562 cells. A multidrug-resistant subline (K562R) was induced to undergo erythroid differentiation by tyrosine kinase inhibitors such as genistein or herbimycin A as effectively as the parent K562 cells were. Therefore, tyrosine kinase inhibitors might be useful as cancer chemotherapeutic agents against some multidrug-resistant leukemias having abnormally high activity of oncogene tyrosine kinase(s).     

Cell cycle-independent down-regulation of BCL-2 protein expression in differentiating HL-60 cells

To understand the relationship between bcl-2 protein expression and the cell cycle during the processes of differentiation, we examined bcl-2 protein levels expressed during cell cycle phases in differentiating HL-60 human leukemia cells by using a two-color flow cytometric method. In exponentially proliferating HL-60 cells bcl-2 protein was constitutively expressed throughout the cell cycle phases, but a small population of G0/G1 cells expressed decreased levels of protein as compared with other cell cycle phases. HL-60 cells can be induced to differentiate to granulocytic pathway by retinoic acid or dimethylsulfoxide, and to monocytic/macrophagic pathway by 1, 25 dihydroxyvitamin D3 or 12-O-tetradecanoylphorbol -13-acetate. During treatment with any of these inducing agents, bcl-2 protein expression was time-dependently down-regulated after 24 h. A two-color flow cytometric analysis revealed that this down-regulation occurred throughout cell cycle phases, indicating that bcl-2 protein expression was down-regulated in cell cycle-independent manner during induction of differentiation in HL-60 cells. To our knowledge, this is the first demonstration suggesting that the regulation of bcl-2 protein expression is not related to the cell cycle during induction of differentiation in HL-60 cells.     

Cell Cycle-Independent Down-Regulation of BCL-2 Protein Expression in Differentiating HL-60 Cells

To understand the relationship between bcl-2 protein expression and the cell cycle during the processes of differentiation, we examined bcl-2 protein levels expressed during cell cycle phases in differentiating HL-60 human leukemia cells by using a two-color flow cytometric method. In exponentially proliferating HL-60 cells bcl-2 protein was constitutively expressed throughout the cell cycle phases, but a small population of G0/G1 cells expressed decreased levels of protein as compared with other cell cycle phases. HL-60 cells can be induced to differentiate to granulocytic pathway by retinoic acid or dimethylsulfoxide, and to monocytic/macrophagic pathway by 1, 25 dihydroxyvitamin D3 or 12-O-tetradecanoylphorbol-13-acetate. During treatment with any of these inducing agents, bcl-2 protein expression was time-dependently down-regulated after 24h. A two-color flow cytometric analysis revealed that this down-regulation occurred throughout cell cycle phases, indicating that bcl-2 protein expression was down-regulated in cell cycle-independent manner during induction of differentiation in HL-60 cells. To our knowledge, this is the first demonstration suggesting that the regulation of bcl-2 protein expression is not related to the cell cycle during induction of differentiation in HL-60 cells.     

视黄酸依赖反义cyclin D1对HL-60细胞细胞周期素依赖性激酶的影响

目的探讨视黄酸(retinoic acid,RA)及其诱导的反义(anti-sense,AS)cyclin D1对HL-60细胞的细胞周期素激酶CDK4的影响.方法通过构建含有视黄酸反应元件(retinoic acid response element, RARE)的反义cyclin D1 RNA表达载体pCI-neo/RARE3-TK/Ascyclin D1,使反义cyclin D1的表达可受视黄酸诱导调控.以脂质体转染HL-60白血病细胞后,运用MTT比色法检测细胞增殖功能、NBT还原实验观测细胞分化状况,RT-PCR以及western-blot等方法观测视黄酸处理后CDK4的mRNA和蛋白表达水平的改变.结果 RA处理后,细胞生长显著减慢,分化能力明显增强,CDK4 mRNA和蛋白表达水平均有所降低,其中,以反义cyclin D1转染细胞经RA处理后变化更为显著.结论 RA及其诱导的反义cyclin D1对HL-60细胞的抑制增殖与诱导分化效应可能与CDK4表达下调有关.     

Inhibition of abl Oncogene Tyrosine Kinase Induces Erythroid Differentiation of Human Myelogenous Leukemia K562 Cells

The human chronic myelogenous leukemia cell line K562 expresses a structurally altered c- abl protein with tyrosine kinase activity. Erythroid differentiation of K562 cells was induced by tyrosine kinase inhibitors, but not by other kinase inhibitors. Treatment of K562 cells with 5'd(TACTGGCCGCTG-AAGGGC)3', complementary to the second exon (codons 2 to 7) of c- abl mRNA, inhibited cell growth and induced benzidine-positive cells in a dose-dependent manner. However, exposure to the sense oligomer did not induce erythroid differentiation of the cells. These results suggest that inhibition of abl tyrosine kinase activity is closely related to induction of erythroid differentiation of K562 cells. A multidrug-resistant subline (K562R) was induced to undergo erythroid differentiation by tyrosine kinase inhibitors such as genistein or herbimycin A as effectively as the parent K562 cells were. Therefore, tyrosine kinase inhibitors might be useful as cancer chemotherapeutic agents against some multidrug-resistant leukemias having abnormally high activity of oncogene tyrosine kinase(s).