The Mechanism Of IGFBP-rP1 Gene In Childhood Acute Leukemias

1 The significance of IGFBP-rP1 expression in childhood acute leukemiasObjective: To explore the role of insulin-like growth factor-binding protein related protein 1(IGFBP-rP1) gene in leukemogenesis and its significance in children acute leukemias.Methods: Real-time quantitative polymerase chain reaction (qRT-PCR) method was used to detect the level of IGFBP-rP1 expression in bone marrow (BM) specimen from 168 children with acute leukemia (AL) at different stages and 30 non-leukemia patients as control. Meanwhile the relationship between the level of IGFBP-rP1 expression and clinical outcome was analyzed according to established clinical prognostic factors.Results: Expression level of IGFBP-rP1 at the initial diagnosed marrow specimen from acute leukemia children was significantly higher than that of non-leukemia children. (M-Estimators are 0.091,0.137 respectively])Expression level of IGFBP-rP1 in newly diagnosed acute myeloid leukemia (AML) is higher than that in newly diagnosed acute lymphocytic leukemia (ALL) (P =0.013), then reduced to less than the control group after complete remission and increased again at relapse(M-Estimator is 0.084). However, IGFBP-rP1 expression level didn't show significant change among three stages in ALL treatment. And the expression level of IGFBP-rP1 has no significant correlation with the risk assessment(P>0.05).Conclusion: IGFBP-rP1 expression demonstrated a close relation with AML at presentation and after treatment which suggested that IGFBP-rP1 may play an important role in leukemogenesis of AML and could be a new MRD marker for AML treatment.2 The mechanism of IGFBP-rP1 gene in Leukemia CellsObjective: To explore the effect of IGFBP-rP1 gene on proliferation,adhesion,migration and invasion in U937 cells after the expression of IGFBP-rP1 was lowered using RNAi. The mechanism of IGFBP-rP1 was studied in AML.Methods: The expression of IGFBP-rP1 in U937 was confirmed by RT-PCR. Three pairs of double-strand siRNA targeting IGFBP-rP1 gene used in the following experiments were purchased from Shanghai GenePharma Co.,Ltd. Optimization in concentration and ratio was performed in order to screen the most effective sequence of siRNAs of IGFBP-rP1 for further experiment. QRT-PCR and Western Blot were used to detect the expression of IGFBP-rP1 in U937 cells after transiently transfected with siRNA of IGFBP-rP1. Cell proliferation, adhesion, transendothelial migration and invasion were performed in transfected cells and controls.Results: After transfected with siRNA of IGFBP-rP1 in U937 cells, the ability of cell proliferation was significantly decreased at 24h (0.580±0.159)compared to normal control and negative contro(l1.049±0.274,0.946±0.195 respectively)(P<0.01); transfected with siRNA targeting IGFBP-rP1 gene, the ability of cell adhesion was significantly lower than their control groups(0.247±0.031 vs 0.406±0.023,0.395±0.011)(P<0.01); cell membrane invasion assay showed that interfere with IGFBP-rP1 gene in U937 to wear invasive ability of membrane less than those in the control groups[(0.387±0.021)×105VS(1.017±0.031)×105, (0.908±0.027)×105; (0.197±0.098)×105 VS (0.493±0.067)×105, (0.469±0.083)×105](P<0.01), the difference was significant.Conclusion: IGFBP-rP1 gene may take part in the development and progression of leukemia by altering the cell proliferation, adhesion, transmembrane and invasion ability.