No abstract available.
HL-60 Cells* ; Humans

No abstract available.
HL-60 Cells* ; Humans ; Luminescence* ; Tretinoin*

PURPOSE: To investigate the pathways of radiation induced apoptosis and the effect of cysteamine (beta-mercaptoethylamine), as a radioprotector, on it. MATERIALS AND METHODS: HL-60 cells were assigned to control, irradiated, and cysteamine (1 mM, 10mM) pretreated groups, Irradiation was given in a single fraction of 10 Gy (6 MV x-ray) and cysteamine was administered 1 hour before irradiation. The activities of caspase-8 were measured in control and irradiated group to evaluate its relation to the radiation induced apoptosis. To evaluate the role of cysteamine in radiation induced apoptosis, the number of viable cells, the expression and activity of caspase-3, and the expression of poly (ADP-ribose) polymerase (PARP) were measured and compared after irradiation the HL-60 cells with cysteamine pretreatment or not. RESULTS: The intracellular caspase-8 activity, known to be related to the death receptor induced apoptosis, was not affected by irradiation (p>0.05). The number of viable cells began to decrease from 6 hours after irradiation (p>0.05), but the number of viable cells in 1 mM cysteamine pretreated group was not decreased afger irradiation and was similar to those in the control group. In caspase-3 analyses, known as apoptosis executioner, its expression was not different but its activity was increased by irradiation (p>0.05). However, this increase of activity was suppressed by the pretreatment of 1mM crysteamine. The cleavage of PARP, thought to be resulted from caspase-3 activation, occurred after irradiation, which was attenuated by the pretreatment of 1mM cysteamine. CONCLUSION: these results show that radiation induced apoptotic process is somewhat different from death receptor induced one and the pretreatment of 1 mM cysteamine has a tendency to decrease the radiation-induced apoptosis in HL-60 cells.
Apoptosis* ; Caspase 3 ; Caspase 8 ; Cysteamine* ; HL-60 Cells ; Humans

HL-60 cells (human promyelocytic leukemia cells) differentiate into the monocyte/macrophage like cells that die spontaneously by apoptosis when treated with 12-O-tetradecanoylphorbol-13-acetate (TPA). It is known that inhibitors of apoptosis proteins (IAP) bind to and inhibit caspase 3, 7, 9 activity and the induction of apoptosis. In this study, we examined the expression of IAP genes during TPA induced differentiation of HL-60 cells. During the differentiation, HIAP-1, HIAP-2, and XIAP expressions were decreased in protein levels. The pan-caspase inhibitor z-VAD-fmk blocked the decrease of HIAP-1 and HIAP-2, which indicates HIAP-1 and HIAP-2 could be caspase substrates. These findings suggest that the decrease of IAP proteins is related to the induction of apoptosis that is associated with TPA- induced HL-60 cell differentiation.
Apoptosis ; Caspase 3 ; HL-60 Cells* ; Humans ; Leukemia

No abstract available.
HL-60 Cells* ; Humans ; Mass Screening* ; Protein Kinases*

No abstract available.
Bone Marrow* ; HL-60 Cells* ; Humans ; Interferon-gamma*

OBJECTIVETo study the expression of annexin II (AnnII) and the fibrinolytic activity in NB4 cells and their alterations in the presence of arsenic trioxide (ATO) and daunorubicin (DNR).

METHODSLeukemia cell line NB4 was treated with ATO or DNR for 24 ∼ 72 h. Cell surface expression of AnnII and its mRNA were analysed by flow cytometry and real time PCR, respectively, the fibrinolytic activity by chromogenic assay.

RESULTSCompared with other acute leukemia cell lines, the expression of AnnII on untreated NB4 cells was relatively higher. The AnnII positive cell rates on NB4, HL-60, K562, and A3 cells were (94.5 ± 1.6)%, (40.1 ± 2.1)%, (36.3 ± 1.5)% and (11.8 ± 2.5)%, respectively. The fibrinolytic activity of NB4 cells was the greatest with a A value of 0.68 ± 0.02. The fibrinolytic activity of NB4 cells was obviously decreased by ATO, DNR or monoclonal antibody against AnnII, being decreased by 60.4%, 35.8% and 26.0% of the pretreatment level, respectively. The expressions of AnnII and its mRNA in NB4 cells were decreased dramatically after ATO and DNR treated for 48 h. Annexin II positive cells rate were (55.46 ± 4.72)% and (27.00 ± 6.18)%, respectively.

CONCLUSIONNB4 cells have strong ability to enhance the catalytic efficiency of the t-PA-dependent plasminogen activation and AnnII on the cell membrane contributes to this activity. Its high fibrinolytic activity can be corrected by ATO and DNR through down-regulating AnnII.

Alkaloids ; Apoptosis ; HL-60 Cells ; Harringtonines ; Humans ; Quinolizines

In order to study the potential of Venus, lentiviral vector, applied to acute myeloid leukemia, the recombinant vector Venus-C3aR was transfected into 293T packing cells by DNA-calcium phosphate coprecipitation. All virus stocks were collected and transfected into HL-60, the GFP expression in HL-60 cells was measured by flow cytometry. The expression level of C3aR1 in transfected HL-60 cells was identified by RT-PCR and flow cytometry. The lentiviral toxicity on HL-60 was measured by using CCK-8 method and the ability of cell differentiation was observed. The results indicated that the transfection efficacy of lentiviral vector on HL-60 cells was more than 95%, which meets the needs for further study. C3aR1 expression on HL-60 cells increased after being transfected with recombinant lentiviral vector. Before and after transfection, the proliferation and differentiation of cells were not changed much. It is concluded that the lentiviral vector showed a high efficacy to transfect AML cells and can be integrated in genome of HL-60 cells to realize the stable expression of interest gene. Meanwhile, lentiviral vector can not affect HL-60 cell ability to proliferate and differentiate.
Genetic Vectors ; HL-60 Cells ; Humans ; Lentivirus ; genetics ; Transfection

OBJECTIVEThe aim of this study was to explore whether rapamycin can induce the autophagy of HL-60 cells and UCH-L3 expression.

METHODSCell proliferation activity of HL-60 cells treated with rapamycin was measured by CCK-8 assay. After the cells were treated with rapamycin for different time, the fluorescent microscopy was used to detect the cells' modality, the morphology of autophagosomes was observed by transmission electron microscopy, the mRNA levels of autophagy-related genes LC3-II and UCH-L3 were detected by real-time PCR, and the Western blot was employed to detect the expression level of UCH-L3.

RESULTSDifferent concentrations of rapamycin could inhibit the proliferation of HL-60 cells. The inhititory levels in treatment groupall were statistically different from those in the control group (P<0.05). Under fluorescent microscopy, the fluorescence intensity in the control group was low, but in the treatment groups it strengthened along with the extension of process time. After treatmant with 2µmol/L rapamycin for different time (12、24 h), the number of autophagosomes in the control group was less , while in the treatment groups was more, the mRNA level of LC3-II was raised as compared with the control group, while the mRNA and protein level of UCH-L3 declined (P<0.05).

CONCLUSIONRapamycin can inhibit the proliferation of HL-60 cells and induce the autophagic death. UCH-L3 may play a role in the regulation of autophagic death of leukemia.