Sex steroids regulate the expression of plasminogen activator inhibitor-1 (PAI-1) and its mRNA in uterine endometrial cancer cell line Ishikawa.

To know the effects of sex steroids on the potentials of growth, invasion, and metastasis with neovascularization of endometrial cancer, the expression of plasminogen activator inhibitor (PAI)-1 [an inhibitor of tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA)] and its mRNA in well-differentiated uterine endometrial cancer cell line Ishikawa was determined by an enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction-Southern blotting (RT-PCR-SB), respectively, under the influence of sex steroids. In Ishikawa cells, either estradiol or progestins (progesterone, medroxyprogesterone acetate, or 17 alpha-hydroxyprogesterone alone) induced the expression of PAI-1 and its mRNA, and those expressions were increased approximately two-fold by both estradiol and progestin administered together. Therefore, sex steroidal induction of PAI-1 might contribute to the inhibition of invasion and metastasis, concomitantly with the inhibition of neovascularization associated with tPA and uPA activities, in well differentiated endometrial cancer.