Effects Of Antisense Oligodeoxynucleotides Targeting VEGF MRNA On Drug-sensitivity Of Leukemic Cells

Objective: To investigate the effects antisense oligodeoxynucleotides of VEGF on survival, growth, chemosensitivity of leukemic cells and observe if regulate expression of VEGF protein and VEGF mRNA . The effective antisense sequences targeted VEGF mRNA be screened. Biological activity of VEGF in leukemias was releaved.Methods: Seven antisense sequences were selected and synthesized , which consisted of 18-20 deoxynucleotide acid and were modified with phosphorothioate , according to principle of low free energy of Overall A 637. Cell growth was assayed by trypan blue dye exclusion assay and level of VEGF protien in the media was determined by ELISA. expression of VEGF mRNA was analysed by RT-PCR , IC50 of Antisense oligodeoxynucleotides of VEGF and drugs were counted by MTT. The morpholologic signs of apoptotic cells were observed by Giemsa staining, the propotion of apoptotic cells was detected by flow cytometry.Results: Six of seven sequences were capable of inhibing growth of HL60, K562 cells and downregulate expression of VEGF protein and mRNA expression significantly. Compared with Scrambed control group , growth of HL60, K562 cells were inhibited by 36.6% ,31.9% , respectively. VEGF protein exprssion of HL60, K562 cells were inhibited by 42.72% , 51.4%, respectively .It was found that there was a close correlation between low level of Overall AG37 and antisense effectiveness (HL60: r=-0.842, P<0.01, K562: r=-0.887, p<0.01). antisense effectiveness showed dose-dependent relation. Signs of apoptosis of K562 cells were not observed.. Antisense oligonucleotide increase the sensitivity of HL60 and K562 cellto As2O3, H, DNR and maekedly promote apoptosisof HL60, K562 to these drugs. Antisense oligonucleotide effectively inhibite survival of primary leukemia cells and enhance the sensitivity and apoptosis of of primary leukemia cells to As2O3, H , DNR,Conclusions:(1) Antisense oligodeoxynucleotides of VEGF effectively inhibited growth of HL60, K562 cells and downregulated expression of the VEGF protein and VEGF mRNA significantly.(2) inhibition proliferation of HL60, K562 cells,,not induce cells apoptosis were the mechanism of inhibing growth of HL60, K562 cells by antisense oligodeoxynucleotides targeted VEGF mRNA, (3) Antisense oligonucleotide increase the sensitivity of HL60 and K562 cell to As2O3 , H , DNR and maekedly promote the propotion of apoptotic of HL60, K562 to these drugs. (4) Antisense oligonucleotide effectively inhibite survival of primary leukemia cells and enhance the sensitivity and the propotion of apoptotic of of primary leukemia cells to As2O3 , H , DNR. (5) computer aided antisense oligodeoxynucleotides design was helpful to obtain antisense sequence with better effects. ( 6) At same time, VEGF had functin of promoting proliferation and decreasing chemosensitivity of leukemic cells. VEGF mRNA may be new target attached by drugs.