| Popis: |
The effect of various mitogenic lectins on the expression of tissue plasminogen activator from human and guinea pig epithelial cells has been investigated. Of the lectins studied, concanavalin-A, at an optimal concentration of 50μg/ml, increased t-PA yield by about 10–15 fold and wheat germ agglutinin by 6–8 fold. Neither pokeweed mitogen nor phytohaemagglutinin had any significant stimulatory effect. A combination of 5-azacytidine, which had previously been shown to increase t-PA expression by 3–5 fold, and concanavalin A did not have an additive effect on t-PA yield. There was no significant difference in cell yield between Con-A treated and control cell cultures, but DNA synthesis, as measured by 3 H-thymidine uptake, did show a transient increase in Con-A treated cultures. Con-A treated cells were found to be more adherent to the substrate suggesting an altered surface morphology, and this may play a modulatory role in t-PA production. |
