Comparative Transcriptomes of Canine and Human Prostate Cancers Identify Mediators of Castration Resistance

Prostate cancer continues to be one of the most lethal cancers in men. While androgen-deprivation therapy is initially effective in treating prostate cancer, most cases of advanced prostate cancer eventually progress to castration-resistant prostate cancer (CRPC), which is incurable. Similarly, the most aggressive form of prostatic carcinoma occurs in dogs that have been castrated. To identify molecular similarities between canine prostate cancer and human CRPC, we performed a comparative analysis of gene expression profiles. Through this transcriptomic analysis, we found that prostatic carcinoma in castrated dogs demonstrate an androgen indifferent phenotype, characterized by low androgen receptor and neuroendocrine associated genes. Notably, we identified two genes, ISG15 and AZGP1 that were consistently up- and downregulated, respectively, in both canine prostatic carcinoma and human CRPC. Additionally, we identified several other genes, including GPX3, S100P, and IFITM1, that exhibited similar expression patterns in both species. Protein-protein interaction network analysis demonstrated that these 5 genes were part of a larger network of interferon-induced genes, suggesting that they may act together in signaling pathways that are disrupted in prostate cancer. Accordingly, our findings suggest that the interferon pathway may play a role in the development and progression of CRPC in both dogs and humans and chart a new therapeutic approach.