Comparison of marker protein expression in benign prostatic hyperplasia in vivo and in vitro.

OBJECTIVE

To use multiple immunofluorescence to compare the in vivo and in vitro expression of tissue-specific proteins in BPH. Materials and methods Pure populations of prostate epithelial and stromal cells were produced using standard methods. Serum-free media for epithelial cells were compared. Co-localization of proteins was compared in frozen-tissue sections and cultured cells by simultaneous multiple immunofluorescence, and recorded using a high-resolution charge-coupled device camera.

RESULTS

In contrast to the other serum-free media tested, epithelial cells grew without squamous differentiation or vacuolation in prostate epithelial growth medium (PrEGM, Clonetics, BioWhittaker UK Ltd., Berks, UK). These cells were predominantly of a basal phenotype, with some cells showing a luminal phenotype. Most of the stromal cells had features of myofibroblasts, but smooth muscle cells and fibroblasts also were present.

CONCLUSION

PrEGM is a commercially available serum-free medium in which primary cultures of prostate epithelial cells can be propagated reproducibly. This study provides a comprehensive description of tissue-specific protein expression in BPH in vivo and in vitro. The use of simultaneous multiple immunofluorescence to study co-localization has resulted in a more precise definition of phenotype than has previously been possible, thereby establishing the relevance of the in vitro model system BPH.