The lipoxygenase metabolite 12(S)-HETE promotes alpha IIb beta 3 integrin-mediated tumor-cell spreading on fibronectin.
Tumor-cell interaction with the vessel wall during metastasis involves adhesion, induction of endothelial-cell retraction and spreading on the exposed sub-endothelial matrix. The signals for initiation of tumor-cell spreading and the receptors involved are unknown. A protocol was developed to distinguish between initial tumor-cell (B16 amelanotic melanoma; B16a) adhesion to and spreading on fibronectin. The time for maximum spreading was 50 min. Treatment with a lipoxygenase metabolite of arachidonic acid [12(S)-HETE] resulted in maximum spreading in 15 min (max. effect approx. 0.1 microM). Other lipoxygenase metabolites were ineffective. 12(S)-HETE treatment induced a rearrangement of F-actin, vinculin, vimentin intermediate filaments and integrin alpha IIb beta 3, but not integrin alpha 5 beta 1. Antibodies to alpha IIb beta 3 but not alpha 5 beta 1 blocked the 12(S)-HETE effect on B16a spreading. B16a-cell attachment to fibronectin resulted in increased metabolism of arachidonic acid to 12(S)-HETE, which was inhibited by lipoxygenase but not by cyclo-oxygenase inhibitors. Accordingly, lipoxygenase inhibitors but not cyclo-oxygenase inhibitors blocked spontaneous B16a-cell spreading. The protein-kinase-C inhibitors calphostin C, H7 and staurosporine also inhibited spreading, while the protein-kinase-A inhibitor H8 was ineffective. These data suggest that B16a-cell spreading on fibronectin is initiated by a lipoxygenase metabolite [12(S)-HETE] of arachidonic acid and is mediated by protein kinase C.
Timar
J
J
Department of Biological Sciences, Wayne State University, Detroit, MI.
Chen
Y Q
YQ
Liu
B
B
Bazaz
R
R
Taylor
J D
JD
Honn
K V
KV
D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D003599:Cytoskeleton / Q000737:chemistry / Q000187:drug effects; D005353:Fibronectins / Q000502:physiology*; D006893:Hydroxyeicosatetraenoic Acids / Q000096:biosynthesis / Q000494:pharmacology*; D016023:Integrins / Q000032:analysis / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D011494:Protein Kinases / Q000502:physiology
D005353:Fibronectins; D006893:Hydroxyeicosatetraenoic Acids; D016023:Integrins; D016718:Arachidonic Acid; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D011494:Protein Kinases