Differential expression of fibronectin receptors during myeloid differentiation and in marrow- and peripheral blood-derived leukemic cells.
A 125I-labeled 120-kDa fibronectin fragment (FN120) containing the RGD binding site was employed to assess FN120 receptor levels in control and dimethylsulfoxide (DMSO)-differentiated HL60 cells, as well as in leukemic peripheral and bone marrow blast cells from acute lymphoid (ALL) and myeloid (AML) patients. Fibronectin CS1 fragment receptor alpha 4 (VLA4-alpha) and RGD-dependent alpha 5 integrin subunits (VLA5-alpha) were characterized by specific monoclonal antibodies (MoAb). HL60 cells, induced along the granulocytic pathway with DMSO, displayed low FN120 binding level densities (36,070 +/- 5142 sites/cell (s/c) vs. 19,780 +/- 4564 s/c, P < 0.005), respectively, for untreated and treated cells) together with decreased VLA5-alpha expression. Granulocytes displayed low levels of FN120 receptors (3167 +/- 1165 s/c) with weak VLA5-alpha expression and absence of VLA4-alpha. Normal lymphocytes displayed 17,670 +/- 8,705 s/c FN120 receptors and VLA4-alpha and VLA5-alpha. The mean FN120 binding levels and mean VLA5-alpha expression were lower in peripheral blast cells, both in ALL and AML, than in the bone marrow leukemic cells. VLA4-alpha remained the same irrespective of cell localization. FN120 binding sites and differential expression of VLA4-alpha and VLA5-alpha integrin molecules on hemopoietic cells could be related to lineage characteristics or cell type distribution within hemopoietic tissue.
Yamamoto
M
M
Disciplina de Hematologia e Hemoterapia da Escola Paulista de Medicina, Universidade de São Paulo, Brazil.
Federico
M H
MH
Maria
D A
DA
Koike
M A
MA
Katayama
M L
ML
Roela
R A
RA
Sonohara
S
S
Brentani
M M
MM
D000293:Adolescent; D000595:Amino Acid Sequence; D001853:Bone Marrow / Q000473:pathology*; D002454:Cell Differentiation / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007951:Leukemia, Myeloid / Q000097:blood*; D008969:Molecular Sequence Data; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000097:blood*; D017469:Receptors, Fibronectin / Q000096:biosynthesis*
D017469:Receptors, Fibronectin