Effect of macrocalyxin A on HL-60 cells proliferation, differentiation and apoptosis / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the effect of macrocalyxin A (MA) on proliferation, differentiation and apoptosis in HL-60 cells and explore its possible mechanisms.</p><p><b>METHODS</b>Different concentration of MA were used to treat HL-60 cells. Proliferation inhibition was analyzed by Trypan blue staining and MTT assay, cell apoptosis by cell morphology, DNA content, cell cycle analysis, Annexin-V/PI and Hoechst 33258 fluorescence staining. The differentiation of HL-60 cells was evaluated by cell morphology, NBT tests and expression of CD11b, CD13, CD14. The expressions of bcl-2, bax, Fas, P53, mitochondrial transmembrane-potential (DeltaPsim) and mitochondrial membrane protein were analyzed by flow cytometry.</p><p><b>RESULTS</b>MA could inhibit HL-60 cells proliferation capacity in a time-and dose-effect, with a 24 h IC50 value of 8.76 microg/ml, 48 h of 7.17 microg/ml and 72 h of 7.14 microg/ml. The HL-60 cells apoptosis was confirmed by cell morphology, sub-G1 phase and Annexin-V/PI labeling in a time and dose dependent manner. The more mature HL-60 cells were a with higher positivity of NBT and expressions of CD11b than those cultured without MA. The expression of bax was increased, while bcl-2, P53, Fas were unchanged on the MA treatment. MA could increase the expression of mitochondrial membrane protein in a dose-dependent manner while the DeltaPsim was reduced.</p><p><b>CONCLUSION</b>MA can inhibit proliferation and induce differentiation and apoptosis of the HL-60 cells. The mechanism may be related with up-regulating bax, opening the mitochondrial permeability transition pore and reducing DeltaPsim.</p>

Effects of sodium nitroprusside on P38MAPK/STAT3 activation and telomerase reverse transcriptase mRNA expression in inducing apoptosis of K562 cell line / 中国实验血液学杂志

This study was aimed to investigate the activation of P38MAPK/STAT3 and expression of telomerase reverse transcriptase during sodium nitroprusside (SNP) inducing apoptosis of human leukemia cell line K562 and to explore the molecular mechanisms of SNP-inducing apoptosis in K562 cells. The K562 cell were treated with different concentrations of SNP and were cultured for different time. Cell apoptosis was analysed by cell morphology, DNA agarose gel electrophoresis, DNA content, and Annexin-V/PI labeling method. The TdT-mediated dUTP nick end labeling (TUNEL) assay was used to quantitate the in situ cell apoptosis. The expressions of phosphorylated p38MAPK or STAT3 were analysed by flow cytometry, while the expression of hTERT mRNA in transcriptional level was measured by fluorescence quantitative RT-PCR. The results showed that SNP inhibited K562 cell growth. The K562 cell apoptosis was confirmed by typical cell morphology and DNA fragment, peak of sub-G1 phase, TUNEL and Annexin-V/PI labeling. A majority of K562 cells were arrested in G0/G1 phase. After treatment with SNP at 0.5-3.0 mmol/L, the expression of phosphorylated-P38MAPK and phosphorylated-STAT3 increased first and decreased afterwards. Incubation of K562 cell with SNP (2 mmol/L) could increase the expression of phosphorylated-P38MAPK and phosphorylated-STAT3 at 12 hours and 24 hours respectively, and down-regulated at 72 hours and 48 hours. SNP could decrease the expression of hTERT-mRNA in time-and dose-dependent manner. It is concluded that SNP can significantly induce K562 cells apoptosis, its mechanism may be related to the activation of P38MAPK and suppression of phosphorylated-STAT3 and hTRET-mRNA.

Mechanism of sodium nitroprusside-induced apoptosis in K562 cell line / 中国实验血液学杂志

To study the molecular mechanisms of nitric oxide donor sodium nitroprusside (SNP) -induced apoptosis in K562 human leukemia cell line, the different concentrations of SNP and different time of culture were used to treat K562 cell. At the same time, potassium ferricyamide (PFC) was used as control, blank was designed in experiment. Cell apoptosis was analysed by cell morphology, DNA agarose gel electrophoresis, DNA content, and annexin-V/PI labeling method. The TdT-mediated dUTP nick end labeling (TUNEL) assay was used to quantify in situ cell apoptosis. Reactive oxygen species (ROS) in cells and mitochondrial transmembrane potential (DeltaPsim) were labeled by dihydrorhodamin 123, 2', 7'-dichlorodihydrofluorescein diacetate and rhodamin 123/PI. bcl-2, bax, bad, p53 gene proteins and mitochondrial membrane protein were analysed by flow cytometry. The results showed that the K562 cell apoptosis was confirmed by typical cell morphology, DNA fragment, sub-G(1) phase, TUNEL and annexin-V/PI labeling. A majority of K562 cells were arrested in G(0)/G(1) phase. During the process of SNP-induced apoptosis in K562 cell, the mean fluorescence intensity of ROS in cells was significantly higher than those in blank and PFC control, while the DeltaPsim reduced. The expression of p53, bax, bad, Fas protein and mitochondrial membrane protein increased and bcl-2 protein decreased after SNP treatment. It is concluded that SNP induces K562 cell apoptosis through increasing ROS in cells, expressing the p53, bax, bad, Fas protein and mitochondrial membrane protein and decreasing bcl-2 protein, opening the mitochondrial permeability transition pore and reducing DeltaPsim. Furthermore, the Fas was activated during the apoptosis process.

Change of Bcl-2, Bax proteins and mitochondrial membrane protein on nitric oxide induced apoptosis in HL-60 cells / 中国实验血液学杂志

To investigate the possible mechanisms of nitric oxide (NO)-induced apoptosis in leukemia cell line HL-60, HL-60 cells in vitro were incubated with sodium nitroprusside (SNP), the in situ cell apoptosis quantitatively was assayed by TdT-mediated dUTP nick end labeling (TUNEL), the cell cycle DNA and proteins expression of Bcl-2, Bax, mitochondrial membrane protein (APO2.7) were analyzed by flow cytometry. The results showed that SNP induced HL-60 cell apoptosis in a dosage- and time-dependent manner. After exposure to SNP at the concentration of 1.0 mmol/L for 48 hours, the percentage of apoptosis HL-60 was (42.2 +/- 3.5)% for subG1 and (52.5 +/- 7.6)% for TUNEL respectively, and they are significantly higher than those in control and potassium ferricyanide (PFC) groups as same concentration. During the apoptosis process, it showed a decrease of Bcl-2 protein and an increase of Bax protein and mitochondrial membrane protein in HL-60 cell, proteins of Bcl-2, Bax and mitochondrial membrane were expressed in a dosage- and time-dependent manner too. In conclusion, during the process of SNP induced apoptosis in HL-60 cell, the expression of mitochondrial membrane protein was increased, Bcl-2 and Bax proteins may be important regulators.