Inhibition of vegfr-2 gene expression by RNA interference / 中国实验血液学杂志

This study was aimed to explore a novel potential gene target for therapy of malignant tumor. The recombinant expression plasmids of VEGF/VEGFR-2 were designed, constructed and then transfected into A549 cells by using lipofectamine. The expressions of VEGF/VEGFR-2 mRNA and protein were detected by RT-PCR and Western blot respectively. The cell proliferation was assayed by CCK-8 and the cell apoptosis was detected using Hoechst Staining. The results indicated that as compared with the blank control, pGenesil-1 and scramble groups, the interference effect of pGenesil-1-vegfr-2-shRNA-1 vector group was more obvious. As the expression of endogenous vegfr-2 mRNA decreased, the expression of VEGFR-2 protein decreased correspondingly. The proliferation of A549 cells was inhibited significantly by RNAi at 72 hours (p<0.01). The apoptosis of A549 cells was induced at 48 hours after being transfected with pGenesil-1-vegfr-2-shRNA-1 and the typical apoptosis morphology could be seen by fluorescence microscopy. It is concluded that the expression of vegfr-2 gene is inhibited effectively by vegfr-2 specific shRNA. The proliferation of A549 cells is inhibited significantly and the apoptosis of cells is induced. This result showed that VEGF/VEGFR-2 signaling pathway can be an effective target for the prevention and treatment of malignant tumor.

Influence of cytochrome C on apoptosis induced by daunorubicine in acute myeloid leukemia (AML) cells / 中国实验血液学杂志

The purpose was to study the responses of AML cell treated with cytochrome C and to explore the influence of cytochrome C on apoptosis of AML cell induced by daunorudicine (DNR). The differentiation of AML cell was detected by Wright-Giemsa staining and NBT test, the apoptosis of AML cell was assayed by flow cytometry and fluorescence microscopy. The results showed as follows: (1) different concentrations of cytochrome C could induce different effects on AML cells. Concentration of cytochrome C for differentiation was 10 microl/ml, for apoptosis was 20 microl/ml, and for necrosis was 40 microl/ml. (2) the apoptosis of AML cells decreased with the administration of cytochrome C in 10.0 microg/ml before treating AML cells with DNR (P < 0.01), but no change was shown with the administration of cytochrome C in 20.0 microg/ml (P > 0.05). (3) in reverse sequence, administrating of cytochrome C in 10 microl/ml and 20 microl/ml after treating AML cells with DNR, two different concentrations of cytochrome C could increase the apoptosis of AML cells (P < 0.01). It is suggested that cytochrome C may probably affect the apoptosis of AML cells induced by DNR.

Effect of cytochrome C on HL-60 cell apoptosis and its relationship with the relevant genes bcl-2 and bax / 中国实验血液学杂志

To study the effect of cytochrome C on HL-60 cells in vitro and the mechanism of expression changes of relevant apoptotic genes, the inhibition rate of cytochrome C on HL-60 cells was detected by MTT, the morphology of HL-60 cells was observed by light microscopy and fluorescence microscopy, the changes of apoptosis rate and cell cycle were assayed by flow cytometry (FCM), DNA ladder was investigated on electrophoresis, the expression changes of bax and bcl-2 mRNA were examined by RT-PCR, when HL-60 cells were treated with different concentrations of cytochrome C for 24 hours. The results showed that the inhibition rate increased with increase of the cytochrome C concentration within 0 - 150 mg/L; when treated with 0 - 37.5 mg/L cytochtome C for 24 hours, the percentage of apoptotic HL-60 cells increased with the dose increasing, and the typical apoptotic cells and the apoptotic DNA ladder were observed. At the same time, within this range of concentration, the expression of bcl-2 mRNA decreased gradually and the expression of bax increased gradually. When the cytochrome C concentration was higher than 37.5 mg/L, the percentage of apoptotic HL-60 cells not increased, but decreased, while the cells necrosed. The above metioned results suggested that at certain range of concentration of cytochrome C, apoptosis or necrosis can be induced by cytochrome C, and cell cycle arrests at G(1) phase in HL-60 cells, the percentage of apoptotic cells and the changes of expression of bax and bcl-2 depend on the dose of cytochrome C. The mechanism that cytochtome C induced apoptosis in HL-60 cells may be related to the activation of bax and inhibition of bcl-2.

Effect of IL-15 on the proliferation, differentiation and anti-apoptosis of CD34+ cells in patients with MDS / 中国实验血液学杂志

To study the effect of interleukin-15 (IL-15) on the proliferation, differentiation and apoptosis of MDS CD34(+) cells, CD34(+) cells of high enrichment were separated by MACS system, and cultured in liquid media with different concentration of IL-15 in treated group and without IL-15 in the control group. Apoptosis of hematopoietic precursors was assayed by propidium iodine staining and cell by FCM, and the other MDS CD34(+) cells were stained by cytochemical staining after culture. The results showed that after culture with IL-15 the proliferation and differentiation of MDS CD34(+) cells were obviously promoted. It was found the every lineage of mature cells developed, the expressions of cell surface antigens CD71, CD33 and CD19 all increased in the MDS CD34(+) cell treated with IL-15. It is suggested that IL-15 stimulates the proliferation and differentiation of MDS CD34(+) cells, and partly shows anti-apoptosis effects which may be applicable to the therapy MDS.