Vitronectin enhances adhesion force and t-PA production of weakly adherent293 cells exposed to a shear stress

The effects of shear stress on the adhesion and productivity of 293 cells w ere studied quantitatively and compared with those of Vero and human liver cells. These cells were cultured in polystyrene dishes by using shear stres s exposing equipment. 50% of 293 cells cultured in 2% FBS supplemented medi um detached from the dish after 29 h of exposure to a shear stress of 0.10 Pa. On the other hand, 90% of Vero and human liver cells remained on the di sh under the same condition. Observations with scanning electron microscopy about cell adhesion plaques on the surface of the dish showed that the are a covered with lamellipodia and the number of microspikes for 293 cells wer e found to be less than those of the other cell lines. Several attachment f actors, especially vitronectin, were found to enhance the number of microsp ikes and the adhesion force of 293 cells. Almost 100% of 293 cells remained on the vitronectin-coated dish after 40 h under 0.10 Pa of shear stress. A higher shear stress (greater than 0.10 Pa) caused a decrease in tissue pla sminogen activator (t-PA) productivity of 293 cells. But 0.03 Pa stimulated the t-PA secretion on the non-coated dish. Vitronectin also enhanced the t -PA secretion even under 0.10 Pa. These results indicate that the adhesion force of 293 cells is obviously weaker than that of the other cell lines, a nd vitronectin enhances the adhesion force and the productivity of 293 cell s exposed to a shear stress.