Genistein and its analogue enhanced tissue plasminogen activator activity in HeLa S3

Soybean isoflavones of genistein and biochanin A, its analogue, promote the activity for generating tissue-plasminogen activator (tPA) from human cervical cancer cells (HeLa S3) and human umbilical vein endothelial cells (HUVEC). At a concentration of 50 microM, each of 14 types of isoflavones were added to HeLa culture solution and incubated. After 24 h, the culture solution was replaced, and then incubated for another 24 h. When fibrinolytic activity was checked in the resulting culture solution using the fibrin plate method, substantial fibrinolytic activity was confirmed for two types of isoflavones. Genistein showed the highest level of fibrinolytic activity at 12.4 times the control, and for biochanin A, an analogue of genistein, the level was 3.5 times the control. Checking fibrinolytic activity and molecular weight of the protein bands separated by zymography, a rise in the protein band concentration in proportion to the concentration of the reagents added was confirmed for the protein band with activity in the same position as the standard reference tPA, which has a molecular weight of about 68 kDa. ELISA also demonstrated that the concentration of tPA in the culture solution was higher than that of plasminogen activator-1. Fibrinolytic activity of HUVEC incubated with 25 microM of biochanin A was much higher than that of the control, which suggests that these soybean isoflavones could have beneficial effects on blood circulation in vivo.