OBJECTIVETo compare the expression and activities of urokinase type plasminogen activator (uPA) among different gastric cancer cell lines and investigate their relations with peritoneal metastatic potency.

METHODSThe uPA expression in 4 gastric cancer cell lines (AGS, SGC7901, MKN45, MKMN28) was detected using ELISA and Western blot methods. uPA activity was detected simultaneously using uPA activity kit. The gastric cancer cells were cultured with confluent mesothelial cells in 24-well plates or Boyden chambers for different times. The adhesive cells were counted directly under a microscope. The motility and invasion of gastric cancer cells were determined by MTT assay.

RESULTSAmong four gastric cancer lines,the highest expression of uPA was found in SGC7901 and the highest uPA activity in MKN45, while the lowest expression and activity of uPA in AGS. Compared with the other three lines, MKN45 had stronger adhesion than MKMN28 (P< 0.05), SGC7901 (P< 0.05), and AGS (P< 0.01), but there were no significant differences in motility and invasion among MKN45, MKN28 and SGC7901. The adhesion,motility and invasion of AGS were weaker compared with those of the other three cell lines.

CONCLUSIONThe uPA expression and activity are significantly different among 4 gastric cancer cell lines, and positively correlated with their peritoneal metastatic potency.