Thrombospondin, a potentiator of tumor cell metastasis.
The platelet-secreted protein thrombospondin (TSP) potentiates tumor cell metastasis. Human TSP injected i.v. into mice 5 min prior to i.v. injection of T241 sarcoma cells potentiates lung tumor colony formation. Several lines of evidence suggest that the TSP-enhancing effect involves both TSP-mediated tumor cell adhesion and the host's hemostatic system: TSP potentiates the initial, rapid sequestering of tumor cells in the lung; TSP promotes the adhesion of tumor cells in vitro; the effect of TSP on tumor cell metastasis is dependent on the presence of platelets and a normal plasma clotting system, since TSP does not potentiate lung tumor colony formation in either thrombocytopenic mice or mice anticoagulated with Coumadin. Our results suggest a central role for TSP in the metastatic process.
D000818:Animals; D001777:Blood Coagulation / Q000187:drug effects; D001792:Blood Platelets / Q000502:physiology; D002448:Cell Adhesion / Q000187:drug effects; D006023:Glycoproteins / Q000494:pharmacology*; D006801:Humans; D008168:Lung / Q000503:physiopathology; D008175:Lung Neoplasms / Q000556:secondary*; D051379:Mice; D008810:Mice, Inbred C57BL; D009362:Neoplasm Metastasis / Q000503:physiopathology*; D009368:Neoplasm Transplantation; D009360:Neoplastic Cells, Circulating; D009439:Neuraminidase / Q000494:pharmacology; D012513:Sarcoma, Experimental / Q000556:secondary*; D013268:Stimulation, Chemical; D019699:Thrombospondins; D014859:Warfarin / Q000494:pharmacology
D006023:Glycoproteins; D019699:Thrombospondins; D014859:Warfarin; D009439:Neuraminidase