Expression of aquaporin 3 in the human prostate

Objective: Aquaporins (AQPs) function as selective pores allowing water, glycerol and other small solutes to pass through the cell membrane. The present study investigated the expression and localization of AQP3 in the human prostate. Methods: Three human prostate cancer cell lines (DU-145, LNCaP and PC-3) and one normal human prostate cell line (PNT1A) were used in this study. Clinical materials from patients with prostate cancer were also used. AQP3 mRNA and protein expression were examined using reverse transcription-polymerase chain reaction and immunohistochemical methods. Results: Aquaporin 3 mRNA was expressed in normal and cancerous prostate cells. Moreover, the expression of AQP3 mRNA was seen in both normal and cancerous epithelia of human prostate tissues, but not in the mesenchyme. In the normal epithelia of the prostate, localization was limited to cell membranes, particularly the basolateral membranes. However, the expression of AQP3 protein in the cancer epithelia was not observed on the cell membranes. Conclusion: The results suggest that water-channel protein may be involved in the preservation of cellular character in the human prostate and prostate cancer is associated with an alteration of water-transporting mechanisms. Changes in the localization of AQP3 in cancer cells may result from tumorigenesis.