Panax Notoginseng Flower Extracted by Methanol on Platelet Function in Healthy Human in Vitro / 中山大学学报(医学科学版)

@#【Objective】To evaluate the effects of methanol extract of Panax Notoginseng flower（PNFM）on platelet function in healthy human.【Methods】Platelet rich plasma were separated from venous blood of healthy volunteers and incubated with different concentrations（0，100，300 and 500 μg/mL）of PNFM for 20 min. After using ADP as agonist， granule-secretion were tested by CD62P expression and ATP release；integrin-αIIbβ3 activation was examined by PAC-1； Test platelet aggregation by turbidimetry ；Immunofluorescence examine platelet spreading on fibrinogen ；Changes in cytoplasmic calcium was studied using Fluo 3-AM，calcium ionophore. 【Results】After using ADP as agonist ，PNFM significantly inhibited platelet aggregation，compared to the control group（72.00±6.08），the 500μg/mL group decreased to 35.67±3.78（P<0.01）；Compared to the control group（30.05±6.48），PNFM reduced the CD62P expression on platelet surface，the 500 μg/mL group decreased to 2.66±0.90（P<0.001）；PNFM inhibited the expression of PAC-1 as a marker of the integrin- αIIbβ3 comformation，compared to the control group（33.37 ± 8.12），the 500 μg/mL group decreased to 11.89±6.12（P<0.01）；Compared to the control group（1.93±0.47），all dose groups attenuated platelet ATP release，the 500 μg/mL group decreased to 35.67±3.78（P<0.01）；Results demonstrated that 500 μg/mL PNFM markedly decreases the surface area of the spreading platelets（89.57±17.34 to 25.12±3.52，P<0.001），and all doses were affected；The Ca2 + mobilization was also reduced by all PNFM doses，compared to the control group（183.87 ± 11.59），the 500 μg/mL group was decreased to 71.25±5.33（P<0.001）.【Conclusions】PNFM attenuated platelet activation，spreading，and aggregation； Our results provided new ideas for prevention and treatment of cardiovascular and cerebrovascular diseases.

The role of Src kinase inhibitor ZD6474 on multi-drug resistant K562/A02 cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the role of Src kinase inhibitor ZD6474 on the growth of multidrug-resistant K562/A02 cells and its regulatory mechanisms.</p><p><b>METHODS</b>The possible mechanisms of drug-resistance were tested by Western blot. Proliferation assays and cell cycle distribution were analyzed by WST metric analysis. Western blot were used to investigate the mechanisms of antiproliferative activity induced by tyrosine kinase inhibitor ZD6474. The in vivo anti-tumor activity was evaluated in K562, K562/A02 xenografted nude mice by administration of ZD6474 (25 - 100 mg×kg(-1)×d(-1), PO).</p><p><b>RESULTS</b>Compared with parental K562 cells, marked high levels of p-Src and Src expression were detected in K562/A02 cells. WST results showed that the IC(50) values of ZD6474 on K562 and K562/A02 after 48 hours incubation were (1.61 ± 0.07) µmol/L and (3.22 ± 0.21)µmol/L, respectively. ZD6474 caused an accumulation of cells in the G(0)/G(1) fraction and apoptosis by inhibiting the expressions of p-Src and Src kinase. Administration of ZD6474 produced a dose-dependent inhibition of tumor growth. 50 mg/kg ZD6474 produced the growth inhibition rates of 43.7% and 56.3%, respectively in K562 and K562/A02.</p><p><b>CONCLUSION</b>Our results indicated that inhibiting Src kinase could induce K562/A02 cells apoptosis in vitro and in vivo.</p>

Effect of ZD6474 on the proliferation of imatinib-resistant K562 cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the effect of tyrosine kinase inhibitor ZD6474 (Vandetanib) on the proliferative inhibition of K562 cells and its derived imatinib-resistant K562/G cells and its mechanism.</p><p><b>METHODS</b>Imatinib-resistant K562/G cells were obtained by culturing cells in gradually increasing concentrations of imatinib. The changed factors related to drug-resistance were tested by Western blot. ZD6474 and imatinib affected K562/G and parental K562 cells proliferation were analyzed by WST assay. Flow cytometry was used to analyze cell cycle. Direct inhibition of Src activity by ZD6474 was measured by a colorimetric ELISA assay with recombinant human Src kinase.</p><p><b>RESULTS</b>10 µmol/L imatinib failed to inhibit K562/G cells proliferation or induce cell cycle arrest. Compared with that in parental K562 cells, there were marked high levels of p-Src and Src protein in K562/G cells. The expression of Bcl-2 and p-STAT3 also increased in K562/G cells. After 48 hours incubation, the IC(50) values of ZD6474 in K562 and K562/G cells were 1.61 µmol/L and 3.18 µmol/L, respectively. ZD6474 treatment caused accumulation of cells in the G(0)/G(1) fraction and cell apoptosis in K562 and K562/G cells. ZD6474 decreased the expression of p-Src and Src at post-transcriptional level. Moreover, ZD6474 increased the ratio of Bax/Bcl-2 and decreased the expression of p-STAT3 at the same concentration for inducing apoptosis.</p><p><b>CONCLUSIONS</b>ZD6474 is effective in inhibiting the proliferation of imatinib-resistant K562/G cells and parental K562 cells, and induces their apoptasis by significant inhibition of Src kinase activity. Our study provides a reliable experimental basis for chronic myeloid leukemia treatment with ZD6474.</p>