[Expression and effect of neuropilin-1 in acute myeloid leukemic cells]

This study was aimed to investigate the expression of neuropilin-1 (NRP-1) and NRP-2 mRNA in myeloid leukemia cells and the effect of NRP-1 on cell proliferation and migration. The expressions of NRP-1 and NRP-2 mRNA in bone marrow mononuclear cells of 24 patients with acute myeloid leukemia and in 7 myeloid leukemic cell lines (HL-60, KGIa, NB4, U937, HEL MEG01 and K562) were detected by RT-PCR. The effects of NRP-1 interfered with siRNA on proliferation and migration in leukemic cell line HEL were examined by MTT and migration test. The results showed that the expression of NRP-1 mRNA was found in bone marrow mononuclear cells (BMMNCS) of 24 AML patients, the positive rate was 100% and significantly higher than that in control group (positive rate 67%). The expressions of NRP-2 mRNA were seen in 79% AML patients and in 67% health control, there was no significant difference between them. The increased NRP-1 expression was directly correlated with the blast percentage in both peripheral blood and bone marrow of AML patients (r=05, r=0.4, p<0.05). The expressions of NRP-1 and NRP-2 mRNA were observed in 6/7 and 3/7 myeloid leukemic cell lines respectively. After HEL cells were transfected with siRNA for 24 hours, the expression levels of NRP-1 mRNA and protein decreased obviously. Under VEGF action, the cell number in control group significantly increased, while the cell proliferation in interfered group had been not changed. After being transfected for 24 hours, the migration in interfered group decreased significantly. It is concluded that the higher level of NRP-1 mRNA is expressed in bone marrow mononuclear cells of leukemia patients and plays a pivotal role in proliferation and migration of myeloid leukemic cells. Inhibition of NRP-1 functions may provide a new therapeutic strategy for AML.