Epithelial-mesenchymal interactions in prostatic development. II. Biochemical observations of prostatic induction by urogenital sinus mesenchyme in epithelium of the adult rodent urinary bladder.

Abstract

Adult [mouse] bladder epithelium (BLE) is induced to differentiate into glandular epithelium after association with urogenital sinus mesenchyme (UGM) and subsequent in vivo growth in syngeneic male hosts. Alterations of epithelial cytodifferentiation is associated with the expression of prostate-specific antigens, histochemical and steroid metabolic activities. Evidently, the inductive influence of the UGM has reprogrammed both the morphological and functional characteristics of the urothelium. Differences regarding the mechanisms and effects of androgenic stimulation of prostate and bladder are exploited to determine the extent to which UGM plus BLE recombinants express a prostatelike, androgen-dependent phenotype. Results from cytosolic autoradiographic binding studies suggest that androgen binding is induced in UGM plus BLE recombinants and that this activity is accounted for by the induced urothelial cells. In UGM plus BLE recombinants, androgen-induced [3H]thymidine or [35S]methionine uptake analyzed by 2-dimensional gel electrophoresis was qualitatively and quantitatively similar to that of prostate as opposed to bladder. Probably, expression within BLE of prostatic phenotype is associated with a loss of urothelial characteristics and androgen sensitivity is presumably a function of the inductive activities of the stroma.