Integrity of actin fibers and microtubules influences metastatic tumor cell adhesion.
Tumor cell adhesion within host organ microvasculature, its stabilization and invasion into host organ parenchyma appear to be important steps during formation of distant metastasis. These interactions of circulating tumor cells with the host organs occur in the presence of fluid shear forces and soluble and cellular environmental conditions of the blood that can modulate their cellular responses and possibly their metastatic efficiency. Cytoskeletal components, such as actin filaments and microtubules, can regulate biophysical characteristics and cellular signaling of the circulating cells. Therefore, we investigated the role of these cytoskeletal structures for early steps during metastasis formation in vivo and in vitro. Using an intravital observation technique, tumor cell adhesion of colon carcinoma cells within the hepatic microcirculation of rats and their invasion into liver parenchyma was observed. Disruption of actin filaments increased cell adhesion, whereas tubulin disruption inhibited adhesive interactions in vivo. The impairment of the cytoskeleton modulated adhesion-mediated cell signaling via focal adhesion kinase (FAK) and paxillin under flow conditions in vitro. In the presence of fluid flow, focal adhesions were enlarged and hyperphosphorylated, whereas stress fibers were reduced compared to static cell adhesion. Disruption of microtubules, however, partially inhibited these effects. Combining the in vivo and in vitro results, our study suggested that changes in cell rigidity and avidity of cell adhesion molecules after disruption of cytoskeletal components appear to be more important for initial adhesive interactions in vivo than their interference with adhesion-mediated cellular signal transduction.
Molecular Biology Laboratory, Department of General Surgery, University Hospital Münster, Germany.
Timo
T
Korb
Kerstin
K
Schlüter
Andreas
A
Enns
Hans-Ulrich
HU
Spiegel
Norbert
N
Senninger
Garth L
GL
Nicolson
Jörg
J
Haier
D008841:Actin Cytoskeleton / Q000378:metabolism*; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000378:metabolism; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006801:Humans; D008099:Liver / Q000098:blood supply / Q000166:cytology / Q000378:metabolism; D008297:Male; D008833:Microcirculation / Q000166:cytology / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D009362:Neoplasm Metastasis / Q000503:physiopathology*; D009369:Neoplasms / Q000378:metabolism*; D051419:Paxillin; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D014404:Tubulin / Q000378:metabolism; D050257:Tubulin Modulators; D014407:Tumor Cells, Cultured
D003598:Cytoskeletal Proteins; C496061:PXN protein, human; D051419:Paxillin; D010750:Phosphoproteins; C496063:Pxn protein, rat; D014404:Tubulin; D050257:Tubulin Modulators; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; C496052:Ptk2 protein, rat