Sodium/Glucose Co-transporter 1 Expression Increases in Human Diseased Prostate

Abstract

Sodium/glucose co-transporter 1 (SGLT1) is an active glucose transporter that takes up glucose into cells independent of the extracellular concentration of glucose. This transporter plays a critical role in maintaining glucose homeostasis at both physiological and pathological levels. The expression level of SGLT1 in normal and diseased human prostatic tissue has not been determined. We produced two rabbit polyclonal antibodies against human SGLT1, one each for immunohistochemical and Western blot analyses, and characterized the expression of SGLT1 in human prostate tissues: normal prostate (n=3), benign prostatic hyperplasia (BPH) (n=53), prostatic intraepithelial neoplasia (PIN) (n=9), and prostate cancer (PCa) (n=44). In normal prostate tissue, SGLT1 was weakly expressed exclusively in the epithelium. The transporter was significantly increased in the basal cells and stromal cells of BPH, increased in the epithelial cells of PIN, and frequently overexpressed in stromal cells and universally overexpressed in the tumor cells of PCa. The pattern of expression was shown as membranous/ cytoplasmic staining in low-grade cancer cells and nuclear envelope staining in high-grade cancer cells. The SGLT1-positive stromal cells of BPH and PCa tissues were negative for tenascin, a marker of reactive stromal cells. We concluded that SGLT1 is up-regulated in BPH and PCa, and SGLT1 may serve as a potential therapeutic target for treating these prostate disorders.