Effect of the interaction between fibronectin and VLA-4 on the proliferation of human B cells, especially a novel human B-cell line, OPM-3.
Very late antigen (VLA)-4 integrin has been suggested to play an important role in haemopoiesis. However, little is known concerning the roles of the fibronectin (FN)/VLA-4 interaction in the proliferation of human B cells. In this study we investigated the effect of immobilized FN on the proliferation of various B-cell lines, including a newly-established B-cell line, OPM-3, and human tonsillar B cells, that primarily express VLA-4 but not VLA-5. Immobilized FN significantly promoted the proliferation of OPM-3 cells and normal B cells via VLA-4. The cross-linking of beta1 integrins of OPM-3 cells resulted in the phosphorylation of the focal adhesion kinase (FAK) associated 90 kD protein, an increase in FAK-associated kinase activity, and the phosphorylation of Raf-1. Furthermore, the MEK1 inhibitor, PD98059, inhibited the FN-promoted proliferation of OPM-3 cells. These results demonstrate that the FN/VLA-4 interaction transmits the growth signal(s) which may be mediated by Ras pathway in OPM-3 cells, and suggest that OPM-3 cells may be of great value in studying the roles of the FN/VLA-4 interaction in human B-cell growth.
Yoshida
H
H
The Second Department of Internal Medicine, Osaka University Medical School, Suita, Japan.
Nishiura
T
T
Karasuno
T
T
Matsumura
I
I
Ishikawa
J
J
Yoshimura
M
M
Yokota
T
T
Okajima
Y
Y
Ogawa
M
M
Kanakura
Y
Y
Tomiyama
Y
Y
Matsuzawa
Y
Y
D001402:B-Lymphocytes / Q000473:pathology*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002455:Cell Division; D003432:Cross-Linking Reagents; D005353:Fibronectins / Q000378:metabolism*; D006801:Humans; D039041:Integrin alpha4beta1; D016023:Integrins / Q000378:metabolism*; D015448:Leukemia, B-Cell / Q000473:pathology*; D016201:Receptors, Lymphocyte Homing / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000378:metabolism
D003432:Cross-Linking Reagents; D005353:Fibronectins; D039041:Integrin alpha4beta1; D016023:Integrins; D016201:Receptors, Lymphocyte Homing; D014443:Tyrosine; D017871:Calcium-Calmodulin-Dependent Protein Kinases