.bcr3/abl2 And Vegf Antisense Oligonucleotides In Combination On K562 Cells In Vivo And In Vitro Studies

Objective: Stimultaneous targeting of BCR-ABL and VEGF could be a rational therapy for Philadephia leukemia. This study was aimed at determining the in vitro and in vivo anti-tumor efficacy of bcr3/abl2 antisense oligodeoxynucleotides (ASO-B3/A2) in combination with VEGF antisense oligodeoxynucleotides (ASO-VEGF).Methods : Antisense oligodeoxynucleotides (AS-ODNs) were synthesized and transfected in K562 cells by Oligofectamine. RT-PCR analysis was performed on total RNA from differently treated cells to assess the levels of bcr3/abl2 and VEGF mRNA expression. Trypan blue exclusion assay was used to determine cell proliferation. For measurement of survival, the MTT assays were performed. Cell apoptosis was analyzed by the fluorescent Annexin V method. A xenotransplant model of human K562 cells was established in nude mice. The mice were subsequently devided into four or five groups and received different treatments were given respectively. The volume of subcutaneous tumors was measured, the number of microvessels was counted and the apoptosis of tumor cells was examined.Results1. At 48 hours after transfection, a partial inhibition of Bcr-Abl mRNA or VEGF mRNA levels using 200 nM ASO-B3/A2 or 200nM ASO-VEGF as compared with the control group. In contrast, the combined treatment with low concentrations of bcr3/abl2 plus VEGF AS-ODNs (100nM each) down-regulated both Bcr-Abl and VEGF mRNA levels.2. 72 hours after the start of transfection, the inhibition of K562 cell proliferation...