Expression Of VEGF And BFGF In Acute Leukemia And Effects Of VEGF Specific Antisense Oligodeoxynucleotide On HL-60 Cell Growth

AIM Recently, higher bone marrow microvessel density(MVD) has been demonstrated in the patients with acute leukemia than in the healthy controls. In order to get insight into the complex connection among MVD increased, angiogenic factor and biological features of acute leukemia cells, we investigate the expression levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in the serum of patients with acute leukemia and supernatants of leukemia cell lines(HL-60, U937, NB4, JM, K562) and effects of VEGF-specific antisense oligodeoxynucleotides (ASODN) on the growth of HL-60 cells. METHODS The levels of VEGF and bFGF in the serum from 32 patients with acute leukemia and 10 healthy subjects and in the supernatants of 5 various human leukemia cell lines were quantified by means of the enzyme-linked immunosorbent assay (ELISA), VEGF levels were standardized by platelet or cell counts and finally expressed as pg.mL-1/10 PLT or pg .mL-1/105 cells to minimize the impact of platelet or cell counts on the results measured; after treatment of HL-60 cells with different concentrations of VEGF ASODN, cell viability was examined with MTT assay and VEGF levels in supernatants were measured with ELISA, respectively. RESULTS Afterstandardization, the serum VEGF levels in the serum from leukemia patients were significantly higher than those in healthy controls (20.43+8.32 vs 0.99+ 0.27pg. mL-1/106PLT, P <0.05); 4 of 5 luekemia cell lines (U937 excluded) were found to expresse VEGF at the levels ranged from 91.19 to 260.98 pg. mL-1/l05cells; bFGF can be detected ( >3 pg.mL-1) in 14 of 32 serum samples from patients with acute leukemia, and the positivity(37.5%) was higher than that in healthy controls(10%); 2 of 5 supernanant samples obtained from leukemia cell lines demonstrated positivity for bFGF, too; after exposure of HL-60 cells to VEGF ASODN at a concentration of 0.125, 0.5, 1 and 5 umol.L-1 for 24h, the cell viability gradually droped to 77.8%+1.2%(P >0.05 vs controls), 61.1%+0.6%(P <0.05 vs controls), 30.9%+0.9%(P <0.05 vs controls) and 22.7% +1.7% (P<0.05 vs controls); after treatment of HL-60 cells with VEGF ASODN at a concentration of 0.1, 1, 5 and 20wmol .L-1 for 24h, the VEGF levels in supernatants of target cells tapered to 164.33+3.56(P >0.05 vs controls), 91.41+7.24(P <0.05 vs controls), 43.15+ 0.98(P<0.05 vs controls) and 35.23+1.24(P <0.05 vs controls) pg . mL-1/l05cells. CONCLUSION The patients with acute leukemia represent the higher levels of serum VEGF and bFGF than controls; most of leukemia cell lines express VEGF and bFGF at different levels; VEGF may plays a pivotal role in the bone marrow angiogenesis of leukemia; VEGF-specific ASODN is able to specifically inhibit HL-60 cell growth with VEGF expression downregulated.