Fluid shear regulates the kinetics and molecular mechanisms of activation-dependent platelet binding to colon carcinoma cells.
This study was undertaken to investigate the kinetics and molecular requirements of platelet binding to tumor cells in bulk suspensions subjected to a uniform linear shear field, using a human colon adenocarcinoma cell line (LS174T) as a model. The effects of shear rate (20-1000 s(-1)), shear exposure time (30-300 s), shear stress (at constant shear rate by adjusting the viscosity of the medium from 1.3-2.6 cP), cell concentration, and platelet activation on platelet-LS174T heteroaggregation were assessed. The results indicate that hydrodynamic shear-induced collisions augment platelet-LS174T binding, which is further potentiated by thrombin/GPRP-NH(2). Peak adhesion efficiency occurs at low shear and decreases with increasing shear. Intercellular contact duration is the predominant factor limiting heteroaggregation at shear rates up to 200 s(-1), whereas these interactions become shear stress-sensitive at > or = 400 s(-1). Heteroaggregation increases with platelet concentration due to an elevation of the intercellular collision frequency, whereas adhesion efficiency remains nearly constant. Moreover, hydrodynamic shear affects the receptor specificity of activation-dependent platelet binding to LS174T cells, as evidenced by the transition from a P-selectin-independent/Arg-Gly-Asp (RGD)-dependent process at 100 s(-1) to a P-selectin/alpha(IIb)beta(3)-dependent interaction at 800 s(-1). This study demonstrates that platelet activation and a fluid-mechanical environment representative of the vasculature affect platelet-tumor cell adhesive interactions pertinent to the process of blood-borne metastasis.
Department of Chemical Engineering, Johns Hopkins University, Baltimore, Maryland 21218 USA.
Owen J T
OJ
McCarty
Sameer
S
Jadhav
Monica M
MM
Burdick
William R
WR
Bell
Konstantinos
K
Konstantopoulos
D000911:Antibodies, Monoclonal / Q000378:metabolism; D055592:Biophysical Phenomena; D001703:Biophysics; D001792:Blood Platelets / Q000378:metabolism* / Q000648:ultrastructure; D002448:Cell Adhesion; D002478:Cells, Cultured; D003110:Colonic Neoplasms / Q000378:metabolism*; D005337:Fibrin / Q000096:biosynthesis; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008854:Microscopy, Electron; D008962:Models, Theoretical; D019007:P-Selectin / Q000096:biosynthesis; D013314:Stress, Mechanical; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D005456:Fluorescent Dyes; D019007:P-Selectin; D005337:Fibrin; D016650:Fluorescein-5-isothiocyanate