Isolation and partial characterization of an epithelial cell line (RPE-F344) from the regenerating prostate of a normal adult male rat

Normal prostate epithelial cells are difficult to propagate in vitro withou t experimental immortalization. The goal of this study was to isolate and c haracterize a propagable epithelial cell line from normal adult rat prostat e. Enrichment of proliferation-competent cells was accomplished in vivo by initiating a single cycle of prostatic involution/regeneration. The RPE-F34 4 cell line was established from an androgen-deprived, involuted prostate f our days after the initiation of regeneration by administration of testoste rone. The cell line has been cultured in vitro for > 50 passages, forms a u niform monolayer in culture, exhibits contact inhibition at confluence, and does not form colonies in soft agar. Immunocytochemical and RT-PCR analyse s demonstrated that the RPE-F344 cells express anti-apoptotic genes associa ted with cell survival, and several growth factor receptors important in pr ostate development and homeostasis. RPE-F344 cells are p27kip1 negative, te lomerase positive, and express high molecular weight cytokeratins specific for prostatic basal cells. They also express low levels of androgen recepto r (AR) and prostatic acid phosphatase (PAP); features associated with secre tory luminal epithelial cells. RPE-F344 cells are maintained in vitro witho ut androgen supplementation, but addition of 15nM dihydrotesterone (DHT) to the culture media results in a significant but transient enhancement of ce llular proliferation. Establishment of RPE-F344-like colonies from rat pros tate is limited to the ventral and dorsal lobes of the prostate 2-4 days af ter initiation of regeneration, suggesting that RPE-F344 cells may originat e from a stem cell-like compartment that is responsible for regenerative re population.