title: In vitro urokinase type plasminogen activator levels and total plasminogen activator activity in squamous cell carcinomas of the head and neck.
abstract: OBJECTIVE
  Determine total plasminogen activator (PA) activity and urokinase-type plasminogen activator (u-PA) levels in cell-free supernatants derived from primary and metastatic squamous cell carcinoma of the head and neck.
  
  
  METHODS
  Plasminogen activator activity was measured by spectrophotometric assay with chromogenic substrate Val-Leu-Lys-para-nitroanilide. Urokinase-type plasminogen activator levels were measured with enzyme-linked immunosorbent assay technique.
  
  
  RESULTS
  Fourteen established squamous cell carcinoma lines from patients with head and neck cancer were assayed for both total PA activity and u-PA levels at 24 to 48 hours of incubation. Compared with control and fibroblast-conditioned media, cell lines established from squamous cell carcinoma of the head and neck had significantly (P < .005) higher levels of both total PA activity and u-PA levels. Linear regression analysis showed a positive correlation (r = .65, P = .007) between total PA activity and u-PA levels.
  
  
  CONCLUSIONS
  Squamous cell carcinomas of the head and neck are able to activate plasminogen and produce u-PA in vitro. The production of PA by squamous cell carcinomas of the head and neck may play an important role in the biology of invasion and metastasis.
authors.affiliation: Department of Otolaryngology, Eye and Ear Institute of Pittsburgh, Pa.
authors.forename: G J
authors.initials: GJ
authors.lastname: Petruzzelli
authors.forename: C H
authors.initials: CH
authors.lastname: Snyderman
authors.forename: J T
authors.initials: JT
authors.lastname: Johnson
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000201:enzymology* / Q000556:secondary; D006258:Head and Neck Neoplasms / Q000201:enzymology*; D006801:Humans; D010960:Plasminogen Activators / Q000096:biosynthesis* / Q000378:metabolism; D012044:Regression Analysis; D013997:Time Factors; D014407:Tumor Cells, Cultured; D014568:Urokinase-Type Plasminogen Activator / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D010960:Plasminogen Activators; D014568:Urokinase-Type Plasminogen Activator