PTEN regulates tumor cell adhesion of colon carcinoma cells under dynamic conditions of fluid flow.
The regulation of integrin-mediated cell adhesion and its stabilization involves different phosphorylation and dephosphorylation events. Focal adhesion kinase (FAK) has been recently found to be a substrate of the dual-specific phosphatase PTEN in glioma cells, where it appears to be involved in regulation of cell spreading and migration as part of focal adhesions. We have investigated the role of PTEN in cell adhesion of HT-29 human colon carcinoma cells under static and hydrodynamic conditions of fluid flow. PTEN coprecipitated with FAK and paxillin dependent on the formation of adhesions to collagens. This corresponded with an adhesion-dependent increase in Tyr-phosphatase activity of PTEN. Using preparations of native FAK and PTEN from HT-29 cells in a specific Tyr-phosphatase assay FAK was identified as substrate for this dephosphorylation. If expression of PTEN was reduced using antisense oligonucleotides cell adhesion under dynamic conditions of laminar flow, but not under static conditions was significantly increased. In addition, cell spreading was increased in cells with reduced PTEN expression. We conclude that PTEN appears to be involved in the regulation of integrin-mediated adhesion through dephosphorylation of FAK. This phosphatase might play a role as a negative regulator for the formation of stable HT-29 cell adhesion to extracellular matrix.
Haier
Jörg
J
The Institute for Molecular Medicine 15162 Triton Lane, Huntington Beach, California, CA 92649, USA. haier@uni-muenster.de
Nicolson
Garth L
GL
D001152:Arsenicals / Q000494:pharmacology; D015153:Blotting, Western; D002448:Cell Adhesion / Q000187:drug effects; D048429:Cell Size; D003094:Collagen / Q000378:metabolism; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006801:Humans; D016376:Oligonucleotides, Antisense / Q000235:genetics; D051059:PTEN Phosphohydrolase; D051419:Paxillin; D010750:Phosphoproteins / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D011485:Protein Binding; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D012212:Rheology; D013314:Stress, Mechanical; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
D001152:Arsenicals; D003598:Cytoskeletal Proteins; D016376:Oligonucleotides, Antisense; C496061:PXN protein, human; D051419:Paxillin; D010750:Phosphoproteins; D025521:Tumor Suppressor Proteins; C029341:oxophenylarsine; D019000:Phosphotyrosine; D003094:Collagen; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human