Vascular endothelial growth factor-induced migration of multiple myeloma cells is associated with beta 1 integrin- and phosphatidylinositol 3-kinase-dependent PKC alpha activation.
In multiple myeloma (MM), migration is necessary for the homing of tumor cells to bone marrow (BM), for expansion within the BM microenvironment, and for egress into the peripheral blood. In the present study we characterize the role of vascular endothelial growth factor (VEGF) and beta(1) integrin (CD29) in MM cell migration. We show that protein kinase C (PKC) alpha is translocated to the plasma membrane and activated by adhesion of MM cells to fibronectin and VEGF. We identify beta(1) integrin modulating VEGF-triggered MM cell migration on fibronectin. We show that transient enhancement of MM cell adhesion to fibronectin triggered by VEGF is dependent on the activity of both PKC and beta(1) integrin. Moreover, we demonstrate that PKC alpha is constitutively associated with beta(1) integrin. These data are consistent with PKC alpha-dependent exocytosis of activated beta(1) integrin to the plasma membrane, where its increased surface expression mediates binding to fibronectin; conversely, catalytically active PKC alpha-driven internalization of beta(1) integrin results in MM cell de-adhesion. We show that the regulatory subunit of phosphatidylinositol (PI) 3-kinase (p85) is constitutively associated with FMS-like tyrosine kinase-1 (Flt-1). VEGF stimulates activation of PI 3-kinase, and both MM cell adhesion and migration are PI 3-kinase-dependent. Moreover, both VEGF-induced PI 3-kinase activation and beta(1) integrin-mediated binding to fibronectin are required for the recruitment and activation of PKC alpha. Time-lapse phase contrast video microscopy (TLVM) studies confirm the importance of these signaling components in VEGF-triggered MM cell migration on fibronectin.
Podar
Klaus
K
Jerome Lipper Multiple Myeloma Research Center/Dana-Farber Cancer Institute and the Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA.
Tai
Yu-Tzu
YT
Lin
Boris K
BK
Narsimhan
Radha P
RP
Sattler
Martin
M
Kijima
Takashi
T
Salgia
Ravi
R
Gupta
Deepak
D
Chauhan
Dharminder
D
Anderson
Kenneth C
KC
D015153:Blotting, Western; D002448:Cell Adhesion; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement; D016228:Endothelial Growth Factors / Q000378:metabolism*; D004789:Enzyme Activation; D005089:Exocytosis; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism*; D008222:Lymphokines / Q000378:metabolism*; D018715:Microscopy, Video; D009101:Multiple Myeloma / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D011233:Precipitin Tests; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D021381:Protein Transport; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors; D014407:Tumor Cells, Cultured; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D005353:Fibronectins; D019012:Integrin beta1; D007527:Isoenzymes; D008222:Lymphokines; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D019869:Phosphatidylinositol 3-Kinases; D020794:Receptor Protein-Tyrosine Kinases; D040281:Vascular Endothelial Growth Factor Receptor-1; C496628:PRKCA protein, human; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha