猪胆酸钠对人早幼粒白血病细胞系(HL-60)作用机理的初步探讨

观察了猪胆酸钠和维甲酸对人早幼粒白血病细胞系(HL-60)体外诱导分化过程中细胞膜脂肪酸的组成、细胞蛋白激酶C(PKC)活性及c-myc癌基因表达的变化,初步探讨猪胆酸钠对HL-60细胞作用的分子机理,结果表明,经100～400μg·ml~(-1)猪胆酸钠处理3d的HL-60细胞,其PKC活性和c-myc表达与对照组比较均明显下调;1μmol·L~(-1)维甲酸诱导3 d的细胞,PKC活性未见明显变化,而癌基因c-myc表达则降至对照组的17％;无论是猪胆酸钠(400 μg·L~(-1))还是维甲酸(1μmol·L~(-1))诱导3d的HL-60细胞,其细胞膜脂肪酸组成均无明显改变。     

Induction of caspase 3 and modulation of some apoptotic genes in human acute promyelocytic leukemia HL-60 cells by carboplatin with amifostine

The influence of carboplatin alone and carboplatin in combination with cytoprotective agent amifostine on the growth, caspase 3 activity and some apoptotic genes expression was investigated in vitro in human acute promyelocytic leukemia HL-60 cells. Proliferation of HL-60 cells exposed to carboplatin dropped down with increasing dose of the drug. This effect was slightly higher when carboplatin was used in combination with amifostine. The cytotoxic index (IC50) was estimated as 6.6 and 4.4 x 10(-4) M (after 24 h) and 3.3 and 2.5 x 10(-5) M (after 48 h) for carboplatin and carboplatin with amifostine, respectively. This effect was accompanied by induction of caspase 3 activity. HL-60 cells treated with carboplatin alone showed about 120-fold increase in caspase 3 activity. Combination of carboplatin with amifostine induced the enzyme activity up to 280 times. Furthermore, the expression of bcl-2, c-myc and bax genes involved in apoptosis as well as p65, which function in this process is unknown, were determined. Semi-quantitative RT-PCR showed a decrease in bcl-2 and an increase in bax, c-myc and p65 expression in HL-60 cells treated with carboplatin in combination with amifostine as compared to the cells treated only with carboplatin. We conclude that amifostine may potentiate carboplatin therapeutic efficiency towards human acute promyelocytic leukemia cells.     

Selective anti-platelet aggregation synergism between a prostacyclin-mimetic, RS93427 and the nitrodilators sodium nitroprusside and glyceryl trinitrate.

1. Citrated platelet-rich plasma from human donors was used to examine turbidometrically the platelet aggregation response to collagen (2.5 micrograms ml-1) and ADP (1.6 microgram ml-1). 2. With collagen as an aggregating agent, the limited (35% maximal inhibition) inhibitory effects of glyceryl trinitrate (GTN, 0.78-50 micrograms ml-1) were markedly potentiated by threshold (3.3-10 ng ml-1) concentrations of RS93427, an orally active prostacyclin-mimetic. Almost complete inhibition of aggregation could then be produced. 3. A threshold concentration of RS93427 (3.3 ng ml-1) similarly potentiated the ability of sodium nitroprusside (NaNp, 0.78-10 micrograms ml-1) to inhibit collagen-induced platelet aggregation. There was an 8 fold reduction in the IC25 concentration of NaNp. 4. Threshold concentrations of the nitrodilators were also able to potentiate the anti-aggregatory effects of RS93427 (0.03-30 ng ml-1) on collagen-induced platelet aggregation. With threshold concentrations of either GTN (6.3-25 micrograms ml-1) or NaNp (0.3-1.3 microgram ml-1), the mean IC50 concentration of RS93427 was reduced 4 or 6 fold, respectively, while the IC25 concentration was reduced 6 or 10 fold, respectively. 5. No similar synergistic interactions were seen between RS93427 and the nitrodilators when ADP was used as an aggregating agent. 6. In spontaneously hypertensive rats, the dose-response for the hypotensive response to bolus doses of RS93427 was not altered by concomitant steady state infusion of a threshold dose (1 micrograms kg-1 min-1) of GTN. 7. Possible therapeutic implications of these findings are discussed.     

Cyclosporine inhibited calcium-mediated apoptosis of HL-60 cells.

AIM: To study the effects of cyclosporine (Cyc) on apoptosis of HL-60 cells. METHODS: Apoptotic cells induced by harringtonine (Har), camptothecin (Cam), or calcimycin (Cal), thapsigargin (Tha) were identified with DNA electrophoresis, morphology, and flow cytometry. Relative [Ca2+]i alteration of apoptotic HL-60 cells were determined with flow cytometry. RESULTS: Cal 1 mg.L-1 or Tha 0.5 mg.L-1 induced apoptosis of HL-60 cells. This effect was inhibited by nontoxic concentration of Cyc 1 mg.L-1. Cyc did not inhibit Har- or Cam-induced apoptosis of HL-60 cells. Both Cal and Tha increased intracellular calcium, whereas Har or Cam did not. CONCLUSION: Cyc inhibited apoptosis only induced by calcium increasement in HL-60 cells. The mechanism of apoptosis induced by Cal or Tha was different from that by Har or Cam.     

十四酰佛波乙酸酯抑制三尖杉酯碱诱导的人白血病HL—60细胞凋亡

目的：研究十四酰佛波乙酸酯（ＴＡ）预处理后，三尖杉酯碱（Ｈａｒ）和喜树碱（Ｃａｍ）诱导人白血病ＨＬ－６０细胞凋亡的变化。方法：染色质凝集观察，流式细胞术，ＤＮＡ琼脂糖凝胶电泳和点杂交。结果：ＴＡ２００ｎｍｏｌ·Ｌ＾－１预处理ＨＬ－６０细胞６ｈ，明显抑制Ｈａｒ０．１ｍｇ·Ｌ＾－１作用３ｈ诱导的细胞凋亡，但只部分抑制Ｃａｍ０．２ｍｇ·Ｌ＾－作用３ｈ诱导的细胞凋亡。ＴＡ预处理ＨＬ－６０细胞明显降低ｃ－ｍ     

Induction of monocytic differentiation by calcitriol (1,25-dihydroxyvitamin D3) in the human promyelocytic leukemic cell line (HL-60) in serum-free medium

The effect of calcitriol on the induction of differentiation in human promyelocytic leukemic cell line (HL-60) cultured in serum-free chemically defined medium (SFM) was investigated. The utilization of SFM containing RPMI-1640 basal medium supplemented with insulin (5 micrograms/ml), transferrin (5 micrograms/ml), sodium selenite (5 ng/ml), and bovine serum albumin (0.5 micrograms/ml), transferrin examination of the cellular/molecular mechanism of calcitriol's action in HL-60 cell differentiation without interference of components present in serum. HL-60 cells grown in SFM were induced to differentiate into monocytes/macrophages by calcitriol as indicated by induction of differentiation-associated biological and biochemical parameters: chemiluminescent (CL) responsiveness, lysozyme activity, nonspecific esterase, expression of cell surface antigens, and reduced proliferation. The exposure of HL-60 cells in SFM to calcitriol (from 10(-10) to 10(-8)M) resulted in dose-dependent induction of these parameters, which was similar to those obtained with cells grown in 10% fetal calf serum containing medium (10% SCM). However, calcitriol was 5-fold more potent for HL-60 cells cultured in SFM than those cultured in 10% SCM as indicated by shifts in dose-response curves for induction of CL responsiveness and lysozyme activity. The effect of calcitriol on the proliferation and acquisition of several monocyte-associated cell surface antigens was also more sensitive for HL-60 cells cultured in SFM than for cells grown in 10% SCM. We characterized and quantitated calcitriol receptors in HL-60 cells cultured in SFM in comparison to those in 10% SCM after exposing intact cells to radiolabeled calcitriol. Cells cultured in either SFM or 10% SCM exhibited calcitriol receptors that migrated at 3.4S as a single peak on sucrose gradients and elicited inherent DNA binding ability. There was essentially no difference in the apparent dissociation constants (Kd) nor in the number of calcitriol binding sites per HL-60 cell, that is approximately 6.0 X 10(-11) M and approximately 3000 binding sites/cell respectively. It is concluded that culturing HL-60 cells in SFM results in full expression of calcitriol-induced phenotypic changes excluding the possibility that such changes result from the indirect effect of calcitriol mediated by identified and/or unidentified components present in serum.     

Interaction between methotrexate and indomethacin on a human normal haemopoietic cell line.

1. The interaction between methotrexate and indomethacin has been examined, at a physiological folate concentration (20 nM), on a human normal lymphoblast-like cell line (RPMI 1788) in vitro. 2. Indomethacin (1 microgram ml-1) increased the reduction of lymphoblast growth caused by methotrexate (10-80 ng ml-1). 3. Indomethacin (0.1 and 1 microgram ml-1) potentiated the cytotoxicity of methotrexate (20 and 40 ng ml-1) after 4 days in culture. 4. Indomethacin (0.4 micrograms ml-1) reduced the accumulation of tritium in lymphoblasts incubated with [3H]-methotrexate after 30 min; therefore initial drug accumulation was not responsible for the potentiation seen after 4 days. 5. If indomethacin increases the killing of human cancer cells by methotrexate in vivo, with a smaller potentiation on lymphoblasts, this combination may be beneficial in treating human malignancy.