Interferon-gamma induces neuroendocrine-like differentiation of human prostate basal-epithelial cells

Prostatic neuroendocrine (NE) cells are intraglandular hybrid epithelial-neural-endocrine cells that express and secrete numerous hormones and neuropeptides, which presumably regulate growth, differentiation, and secretory activity of the prostatic epithelium. This specialized cell type appears to differentiate from a common basal/precursor/stem cell that also gives rise to the secretory epithelium. In order to elucidate mechanisms of NE-differentiation the effects of type 1 (alpha, beta) and type 2 (gamma) interferons (IFNs) on human prostate basal cells (PrECs) were evaluated.

Application of alpha/beta IFN increased the expression of the cell-cycle inhibitor p21(CIP1) and inhibited DNA synthesis, while only IFN-gamma led to increased apoptosis, cell-cycle inhibitor p27(KIP1) upregulation, and differentiation of PrECs into NE-like cells. In vitro differentiated NE-like cells expressed the glycolytic enzyme neuron-specific enolase (NSE) and chromogranin A (CgA), known markers of NE-cells in vivo in the prostate. These NE-like cells also changed cytokeratin (CK) expression patterns by upregulating CK 8/18, predominantly found in terminally-differentiated secretory luminal/NE epithelial cells.

IFN-gamma produced locally in the prostate by basal cells and, under proinflammatory conditions, by infiltrating lymphocytes could support NE cell differentiation and play a role in NE differentiation processes of tumor cells in hormone-refractory prostate cancer.