Identification of genes targeted by the androgen and PKA signaling pathways in prostate cancer cells.

Progression of prostate cancer to androgen independence is suspected to involve the androgen and protein kinase A (PKA) signaling pathways. Here for the first time, the transcriptomes associated with each pathway and common transcriptional targets in response to stimulation of both pathways were identified in human prostate cancer cells using Affymetrix GeneChip technology (Human Genome U133 plus2). Statistically significant changes in the levels of 858 genes in response to androgen and 303 genes in response to activation of the PKA pathway were determined using GeneSpring software. Expression of a subset of these genes (22) that were transcriptional targets for the androgen and/or PKA pathways were validated by reverse transcriptase-polymerase chain reaction and Western blot analyses. Application of small interfering RNAs to the androgen receptor (AR) revealed that in addition to KLK3, levels of expression of KLK2 and SESN1 were regulated by AR activated by both the androgen and PKA signaling pathways. SESN1 was identified as a gene repressed by activated AR. These results provide a broad view of the effects of the androgen and PKA signaling pathways on the transcriptional program of prostate cancer cells and indicate that only a limited number of genes are targeted by cross-talk between AR and PKA pathways.