Androgen induces differentiation of a human papillomavirus 16 E6/E7 immortalized prostate epithelial cell line

Androgen signaling is crucial for the growth and development, as well, as f or tumorigenesis of the prostate. However, many of the prostate epithelial cell lines developed previously, either normal or tumorigenic, do not expre ss androgen receptor (AR) or respond to androgen. In order to advance our u nderstanding on how androgen signaling regulates the gowth and the differen tiation status, and affects tumorigenicity of the epithelial cell, we perfo rmed experiments on HPr-1, a prostate cell line recently immortalized from normal human prostate epithelial cells. In the present study, AR was stably transfected into HPr-1 cells by replication-detective retrovirus. Treatmen t of HPr-1AR cells with androgen resulted in cell differentiation and growt h retardation accompanied with up-regulation of cytokeratins KS and K18, pr ostate specific antigen, p21 and p27, and down-regulation of c-myc, bcl-2 a nd telomerase activity. Our results suggest that androgen promotes the proc ess of differentiation in a human papillomavirus 16 E6/E7 immortalized pros tate epithelial cell line which may reflect the normal effects of androgen on prostate cells.