The Interaction Of ICAM-1 And LFA-1 In Adhesion Of AML Blasts And HUVECs

Leukostasis and myeloblast migration to tissues in AML is a life-threatening complication and may lead to rapidly multiple organ failure and death. But the mechanisms of leukostasis and myeloblast migration are poorly understood. The intercellular adhesion molecule-1 (ICAM-1) with their ligands lymphocyte function-associated antigen -1 (LFA-1) has a key role in normal leukocyte adhesion and migration. To evaluate the effect of interaction of ICAM-1 and LFA-1 in adhesion of AML blasts to human umbilical vein endothelial cells (HUVECs). We studied the adhesion between AML blasts and HUVECs in vitro and the role of interaction of ICAM-1 and LFA-1 in this adhesion. We investigated the AML blasts and HUVECs attachment assays and adhesion blockade assay; Observed the effect of the supernatant of AML blasts to the adhesion of the normal neutrophils and unactivated HUVECs; Analyzed the expression of ICAM-1 mRNA and proteins level of HUVECs by RT-PCR and Western blot; Determined the ICAM-1 on the surface of HUVECs and LFA-1 on AML blasts by Flow cytometry; Evaluated the TNF-a and IL-1 expression in AML blasts supernatant by RIA kit and ELISA. The results showed that the AML blast cells and normal mononuclear cells attached to unactivated HUVECs were significantly fewer than that to the TNF-a activated-HUVECs, it means that TNF-a could activate the HUVECs to enhance the attachment of AML blast cellsThe Interaction of ICAM-1 and LFA-1 in Adhesion of AML Blasts and HUVECsor normal mononuclear cells; Prolonging incubation of AML blast and unactivated HUVECs for 24 hours could increased significantly the attachment; The adhesion of neutrophils and unactivated HUVECs treated with AML blasts supernatant increased significantly compared with that of the control with neutrophils and HUVECs treated with supernatant of normal mononuclear cells, revealed that the supernatant of AML blast cells could facilitate the adhesion of HUVEC; HUVECs with AML blasts supernatant for 24 hours could increased the expression of HUVECs ICAM-1 mRNA and proteins level and also facilitate the expression of ICAM-1 on the surface of HUVECs, indicated that supernatant of AML blast might have the ability to stimulate HUVEC expressing more ICAM-1 and might be tend to adhesion to HUVEC; In adhesion blockade assay, the anti-ICAM-1 and anti-LFA-1 could significantly inhibit the adhesion of AML blasts and TNF-cc activated- HUVECs, indicating an important role for ICAM-1 and LFA-1 in attaching AML blast cells to TNF- a activated- HUVECs; TNF- a and IL-1 P expression in the supernatant of AML blasts were increased significantly compared with that in the supernatant in normal bone marrow mononuclear cells. Highly significant positive relationship were found between the levels of TNF- a and IL-1 P expression in the supernatant of AML blasts and the levels of ICAM-1 expression on HUVEC incubated with AML blast supernatant, suggested that AML blasts activating HUVECs to express ICAM-1 was possibly induced by releasing TNF- a and IL-1 3 . In conclusion, this observation suggests that AML blasts can be able to increase the expression of TNF- a and IL-1 3 stimulating factors, which stimulateShanxi Medical University Academic Dissertation for Doctorateendothelium to secrete ICAM-1 and promote their own adhesion to vascular endothelium. The interaction of ICAM-1 and its ligand LFA-1 has a key role in adhesion of AML blasts and HUVECs.