title: Plasmin induces the formation of multicellular spheroids of breast cancer cells.
abstract: MCF7 and ZR75-1 breast cancer cells grow as adherent monolayers in tissue culture. Treatment with the serum serine protease plasmin causes them to detach and to grow as floating multicellular spheroids. Two plasmin activators, urokinase plasminogen activator and streptokinase, induce the same growth pattern changes in the presence of plasminogen. Serum contains also plasminogen activator inhibitors. Aged serum, deficient in plasminogen activator inhibitors, converts spontaneously monolayer breast cancer cells into multicellular spheroids which readily revert to monolayer growth after addition of fresh serum. Urokinase blocks the reversion. The formation of multicellular spheroids does not affect the proliferative rate of breast tumor cells but endows tumor cells with increased resistance to the chemotherapeutic drugs, doxorubicin and paclitaxel.
authors.affiliation: Department of Microbiology and Immunology, New York Medical College, Valhalla 10595, USA.
authors.forename: M H
authors.initials: MH
authors.lastname: Chun
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D001943:Breast Neoplasms / Q000201:enzymology / Q000473:pathology*; D002448:Cell Adhesion / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D004317:Doxorubicin / Q000494:pharmacology; D005341:Fibrinolysin / Q000494:pharmacology; D006801:Humans; D009940:Organoids / Q000473:pathology; D017239:Paclitaxel / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014568:Urokinase-Type Plasminogen Activator / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D004317:Doxorubicin; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator; D017239:Paclitaxel