Elimination of hydrocortisone from the medium enables tissue plasminogen activator gene expression by normal and immortalized nonmalignant human epithelial cells

Human cervical epithelial cells transfected and immortalized with human pap illomavirus type 16 DNA (HCE16/3) can be, like many other epithelial cells, normally grown in medium supplemented with epidermal growth factor, choler a toxin, hydrocortisone, insulin, transferrin, thyroid hormone and serum. W e found that hydrocortisone diminished tissue plasminogen activator (tPA) p roduction to an undetectable level. The removal of hydrocortisone increased urokinase plasminogen activator (uPA) activity within 24-48 h and tPA acti vity within 48-72 h, and converted the cells to a more elongated and fibrob lastic phenotype. Upregulation of uPA mRNA was seen as early as at 3 In and of tPA mRNA within 48-72 h. Higher molecular weight forms (97-110 kDa) of plasminogen activators were seen in zymograms, apparently complexed with PA I-11, starting at 6 h both in the presence and absence of hydrocortisone. I mmunoprecipitation with a PAI-11 monoclonal antibody confirmed that both uP A and tPA were complexed. We also studied normal diploid human bronchial ep ithelial cells (NHBE) and NHBE cells transformed with an adeno-12/SV40 hybr id virus (BEAS-2B). In both types of nonmalignant epithelial cells, the rem oval of hydrocortisone increased uPA activity. The omission of hydrocortiso ne increased tPA levels significantly in BEAS-2B cell cultures, and in NHBE cell cultures tPA became detectable at 72 h. No PA complexes were seen in these two cell types. We conclude that normal and immortalized nonmalignant epithelial cells produce tPA, but only if hydrocortisone is omitted in the growth medium.