[Effect of IGFBP7 gene down-regulation on leukemia cells]

To explore the effect of down-regulation of insulin-like growth factor binding protein 7 (IGFBP7) on the proliferation and invasiveness of leukemia cell line U937 cells.

Three pairs of double-strand siRNA targeting IGFBP7 gene were transfected into SMMC7721 cells to select the most efficient one for U937 cells. qRT-PCR and Western blot were used to detect the expression of IGFBP7 in U937 cells after transiently transfected with siRNA of IGFBP7. Cell proliferation, adhesion, trans-endothelial migration and invasion were performed in transfected cells and control groups.

After transfected with siRNA of IGFBP7 in U937 cells, the ability of cell proliferation was significantly decreased at 24 h (0.580 ± 0.159) compared to that of parental cells and scramble negative control (1.049 ± 0.274, 0.946 ± 0.195, respectively) (P < 0.01). Adhesion of U937 cells transfected with IGFBP7 gene specific siRNA to ECV304 cells was significantly lower than that of the control groups (0.247 ± 0.031 vs 0.406 ± 0.023 and 0.395 ± 0.011) (P < 0.01). Transendothelial membrane of U937 cells into the bottom of the 24-well plate for experimental group were less than those in the control groups \[(0.387 ± 0.021)×10(5) vs (1.017 ± 0.031)×10(5) and (0.908 ± 0.027)×10(5)\]. Cells adherent to the matrigel for experimental group were less than those in the control groups \[(0.197 ± 0.098)×10(5) vs (0.493 ± 0.067)×10(5) and (0.469 ± 0.083)×10(5)\]. The difference was significant (P < 0.01).

IGFBP7 gene plays a contributing role in leukemogenesis involving in leukemic cells' proliferation and interaction with endothelial cells through adhesion, invasion and migration.