PAC1-R null isoform expression in human prostate cancer tissue

BACKGROUND. PACAP is a member of the VIP/GHRH family of neuropeptides and has important effects on prostate cell proliferation. Here we analyze the expression and localization of PACAP and its specific receptor variants (PAC₁-R) in tissues collected from patients undergoing prostate biopsy and surgery for benign prostatic hyperplasia (BPH) and prostate cancer (PCa). METHODS. Reverse transcriptase (RT)-polymerase chain reaction (PCR), DNA sequencing, and immunohistochemistry. RESULTS. PACAP and PAC₁-R were localized by immunohistochemistry in the prostate tissue. While in healthy and BPH tissues PAC₁-R positive staining is present in all the epithelial cells lining the lumen of the acini and in some stromal cells (mostly in the apical portion of the cells), in PCa tissues, anti-PAC₁-R antibody stained the apical portion of the cells. We provide evidence that PAC ₁-R null and SV₁/SV₂ variants are all present in normal and hyperplastic tissues, while in PCa tissue PAC₁-R null is the most relevant receptor variant expressed. CONCLUSIONS. Our data demonstrates that the PAC₁-R null variant is the most relevant isoform expressed in human PCa tissue being suggestively related with the events determining the outcome of prostate cancer.