EXPRESSION OF TISSUE KALLIKREIN IN NORMAL AND SV40-TRANSFECTED HUMAN ENDOMETRIAL STROMAL CELLS

The polymerase chain reaction with specific tissue kallikrein primers was utilized to demonstrate the presence of tissue kallikrein mRNA in human endometrial stromal cells. Enzymatic analysis measured with a sp ecific tripeptide nitroanilide substrate demonstrated the presence of tissue kallikrein in the conditioned medium obtained from both normal stromal cells and stromal cells transfected with an origin-defective t emperature-sensitive SV40 large T antigen. The transfected stromal cel l supernatant exhibited approximately twice as much tissue kallikrein activity as normal stromal cells at 60-100 % of cell confluence. The r elease of tisseu kallikrein from transfected stromal cells was confirm ed by Western blot analysis and [S-35]-methionine incorporation into a 35-kD protein which retains tissue kallikrein activity. These results demonstrate for the first time the expression and secretion of tissue kallikrein in human endometrial stromal cells and provide evidence of possible involvement of tissue kallikrein in cell transformation.