Differential expression of hZnT-4 in human prostate tissues

BACKGROUND: Altered zinc levels in prostate benign prostatic hyperplasia (BPH) and carcinoma is well documented. It is not known whether loss of zinc, necessary to restrain aggressive growth, results from loss of a single specific or multiple zinc transporters. METHODS: Human prostate tissues from patients who underwent radical prostatectomy were screened by RT-PCR analysis for five zinc transporters. Relative cDNA expression was determined in normal, BPH, and tumor specimens and four prostate epithelial cell lines. RESULTS: Surgical specimens were obtained from patients with assigned Gleason scores ranging from 5 to 9. Relative expression of hZIP-1 and hZnT-1 were prominent in most samples with relatively lesser degree of expression of hZIP-2 and no detectable expression of hZnT-3. Expression of hZnT-4 was decreased in BPH and tumor samples compared to normal tissue. CONCLUSIONS: These data suggest that zinc homeostasis in normal prostate tissues results from an interplay of multiple transporters and decreased hZnT-4 expression is associated with prostate tissue abnormalities independent of total cellular zinc content.