Facilitative UT-B urea transporters play a pivotal role in maintaining urea homeostasis by regulating levels of urea in various tissues of the human body. However, the precise regulatory mechanisms governing UT-B expression and activity in different tissues remain to be elucidated. Dysregulation of UT-B transporters has also been implicated in numerous pathological conditions including renal disorders, metabolic diseases, and certain cancers, underscoring the significance of understanding their regulatory mechanisms. This current study therefore compared the levels of both UT-B RNA and UT-B protein in various human cell lines – namely PC-3 (prostate adenocarcinoma), PWR-1E (prostatic epithelia), HT-29 (colorectal adenocarcinoma), and RT-4 (urinary bladder epithelia) – to investigate the regulatory mechanisms governing human UT-B expression. Initially endpoint RT-PCR experiments revealed detectable levels of UT-B RNA in PC-3, HT-29, and RT-4 cells. However, despite the presence of RNA, western blotting experiments detected no significant UT-B protein abundance in either the PC-3 or HT-29 cell lines (All NS, N = 3-4, unpaired T-test). In contrast to these findings, our analysis demonstrated a high UT-B protein abundance level in RT-4 cells and a moderate protein abundance level in the PWR-1E cell line (N = 4), with a 30-35 kDa UT-B1 signal/protein. Experiments were then carried out to assess if urea treatment could regulate UT-B abundance in the PWR-1E cell line, however, no significant changes were observed with either 24 or 48 hour exposure to 5mM urea (NS, N = 4, unpaired T-test). This disparity between the cell lines emphasises potential differences in cellular pathways governing protein synthesis and confirmed variances between UT-B1 protein abundance in ‘normal’ and cancerous prostate. Elucidating the intricate mechanisms governing UT-B abundance and its functional implications within prostate cells holds promise for advancing our understanding of prostate physiology and pathology.
    
KEYWORDS
Urea; UT-B transporter; protein