Function of alpha3beta1-tetraspanin protein complexes in tumor cell invasion. Evidence for the role of the complexes in production of matrix metalloproteinase 2 (MMP-2).
Tumor cell migration through the three- dimensional extracellular matrix (ECM) environment is an important part of the metastatic process. We have analyzed a role played by the integrin-tetraspanin protein complexes in invasive migration by culturing MDA-MB-231 cells within Matrigel. Using time-lapse video recording, we demonstrated that the Matrigel-embedded cells remain round and exhibit only limited ability for migration by extending short, highly dynamic pseudopodia. The alpha3beta1-tetraspanin protein complexes were clustered on the thin microvilli-like protrusions extending from both the main cell body and pseudopodia. Ligation of the alpha3beta1-tetraspanin protein complexes with monoclonal antibodies specifically stimulates production of matrix metalloproteinase 2 (MMP-2) and induces formation of long invasive protrusions within Matrigel. Accordingly, treatment with the monoclonal antibodies to various tetraspanin proteins and to the alpha3 integrin subunit increases invasive potential of the MDA-MB-231 cells in the Matrigel-penetration assay. A specific inhibitor of phosphoinositide 3-kinase (PI3K), LY294002, negated the effect of the monoclonal antibodies on the morphology of the Matrigel-embedded cells and on production of MMP-2. Interestingly, broad-spectrum inhibitors of protein tyrosine kinases (genistein) and protein tyrosine phosphatases (orthovanadate), and actin filament stabilizing compound (jasplakinolide), also block protrusive activity of the Matrigel-embedded cells but have no effect on the production of MMP-2. These results indicate that alpha3beta1-tetraspanin protein complexes may control invasive migration of tumor cells by using at least two PI3K-dependent signaling mechanisms: through rearrangement of the actin cytoskeleton and by modulating the MMP-2 production.
Sugiura
T
T
CRC Institute for Cancer Studies, The University of Birmingham, Edgbaston, Birmingham B15 2TA, United Kingdom.
Berditchevski
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D000199:Actins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D000911:Antibodies, Monoclonal; D001943:Breast Neoplasms / Q000201:enzymology / Q000378:metabolism / Q000473:pathology*; D002448:Cell Adhesion / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D003094:Collagen; D004338:Drug Combinations; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005109:Extracellular Matrix / Q000378:metabolism; D018093:Gelatinases / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D039201:Integrin alpha3beta1; D016023:Integrins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007797:Laminin; D020778:Matrix Metalloproteinase 2; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D008970:Molecular Weight; D009361:Neoplasm Invasiveness; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D011509:Proteoglycans; D011554:Pseudopodia / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D014407:Tumor Cells, Cultured
D000199:Actins; D000911:Antibodies, Monoclonal; D003094:Collagen; D004338:Drug Combinations; D004791:Enzyme Inhibitors; D018093:Gelatinases; D039201:Integrin alpha3beta1; D016023:Integrins; D007797:Laminin; D020778:Matrix Metalloproteinase 2; D008565:Membrane Proteins; D008666:Metalloendopeptidases; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011509:Proteoglycans; C059485:matrigel