6′-sialyllactose ameliorates in vivo and in vitro benign prostatic hyperplasia by regulating the e2f1/prb–ar pathway

Background: 6′-Sialyllactose (6SL) displays a wide range of the bioactive benefits, such as anti-proliferative and anti-angiogenic activities. However, the therapeutic effects of 6SL on benign prostatic hyperplasia (BPH) remain unknown. Methods: Six-week-old male Wistar rats (n = 40) were used for in vivo experiments. All rats were castrated and experimental BPH was induced in castrated rats by intramuscular injection of testosterone, with the exception of those in the control group. Rats with BPH were administrated finasteride and 0.5 or 1.0 mg/kg 6SL. Furthermore, the inhibitory effects of 6SL on human epithelial BPH cell line (BPH-1) cells were determined in vitro. Results: Rats with BPH exhibited outstanding BPH manifestations, including prostate enlargement, histological alterations, and increased prostate-specific antigen (PSA) levels. Compared to those in the BPH group, rats in the 6SL group showed fewer pathological changes and normal androgen events, followed by restoration of retinoblastoma protein (pRb) and cell cycle-related proteins. In BPH-1 cells, treatment with 6SL significantly suppressed the effects on the androgen receptor (AR), PSA, and E2F transcription factor 1 (E2F1)-dependent cell cycle protein expression. Conclusions: 6SL demonstrated anti-proliferative effects in a testosteroneinduced BPH rat model and on BPH-1 cells by regulating the pRB/E2F1–AR pathway. According to our results, we suggest that 6SL may be considered a potential agent for the treatment of BPH.