Effect In Proliferation And Apoptosis Of Recombinant Human Vascular Endothelial On K562and K562/A02Cells Of Myeloid Leukemia

BackgroundChronic Myeloid Leukemia (CML),one of the most common myeloproliferative disorders, is amalignant disease of the human hematopoietic stem cell. The main characteristic of the CML is the ectopicgene of the t(9;22) q(34;11) which is called Philadelphia chromosome(Philadelphia chromosome, Ph),andresulting in theBCR-ABL fusion gene. BCR-ABL fusion gene is related to the pathogenesis of chronicmyeloid leukemia (CML), and the oncoprotein p210which is encoded by the BCR-ABL with anti-apoptoticactivity.Imatinib resistance, occurring in nearly33%of patients, has been associated with a variety ofmechanisms subclassified as BCR-ABL-dependent or BCR-ABL-independent mechanisms. Themechanisms of IM resistance, which are including BCR-ABL-dependent or BCR-ABL-independent, willlead to the failure of the IM treatment. Although the second and third generation TKIs have permitted tocure the CML, the price of the drugs is so high and is still limitations. More and more data have shown that,neovascularization is taking part in the occurrence and progress of the leukemia. Anti-angiogenesis isbecoming a new treatment for the CML. If the balance between proliferation and cell death is broken, thismay directly lead to the tumor expansion. Defects in the apoptotic machinery may contribute to themalignant phenotype in CML. BCL-2family, a member of the anti-apoptotic protein, is related to theapoptosis of the cell. The overexpression of the BCL-XL and BCL-2, which are the members of the BCL-2family, is usually appeared in the tumor and the cancer.Objective1.Study of recombinant human endostatin (recombinant human endostatin, rhES) of K562/A02proliferation of chronic myeloid leukemia cell line K562chronic myeloid leukemia multidrug resistant cellline inhibition.2.Research K562, K562/A02cell strains after rhES role observe the cells secrete apoptotic proteinBCL-2, BCL-XL and vascular endothelial growth factor (VEGF) expression levels change. Research Methods1.K562and K562/A02cells were cultured in the incubator at37℃,5%CO2until the growth of thecells are stabile. To observe the cell morphology and growth status of the K562and K562/A02cells underthe microscope; counting the cell growth curve.2.K562cells and K562/A02cell were cultured with diferent concentrations of rhES(0、10、20、50、100、200�'�400μg/ml)for6-72h. Cell viability and IC50values were determined by CCK-8assay.3.IC50values acted as the role of concentration and time on the and the apoptosis of the K562andK562/A02cells was conducted by AnnexinV/PI．4.The expression of the BCL-2, BCL-XL, VEGF were detected by Elisa and RT-PCR.Results1.The result of CCK-8showed that the rhES could inhibit the growth of K562and K562/A02cellssignificantly (P<0.05) in a time-and dose-dependent manner. After K562cells and K562/A02cell werecultured with rhES for24h and48h, the IC50values were100μg/ml and200μg/ml.2.The AnnexinV/PI tests showed that K562was cultured in the rhES at100μg/ml and200μg/ml for24h, the apoptosis rate of the cell was13.60%and14.84%. When the K562cell was cultured in the rhESat100μg/ml and200μg/ml for48h, the apoptosis rate of the cell was20.02%and23.64%.When the K562/A02cell was cultured in the rhES at100μg/ml and200μg/ml for24h, the apoptosisrate of the cell was10.97%and16.57%. When the K562/A02cell was cultured in the rhES at100μg/mland200μg/ml for48h, the apoptosis rate of the cell was13.33%and15.42%.3.The results of Elisa and RT-PCR showed that, after the rhES acted on the K562and K562/A02cells,the expression of the BCL-2, BCL-XL, VEGF has decreased remarkably（P＜0.05）.Conclusion1.RhES can inhibit K562and multi-drug resistance of leukemia cell lines K562/A02cells proliferationin vitro and also can induce the apoptosis of the two cells.2.RhES can reduce the expressions of BCL-2, BCL-XL,VEGF in the K562and K562/A02cells.