Sasanquasaponin inhibited epithelial to mesenchymal transition in prostate cancer by regulating the PI3K/Akt/mTOR and Smad pathways.

Context: Sasanquasaponin (SQS) is a commonly used traditional Chinese medicine proved to have a wide range of pharmacological functions.

Objective: The objective of this study is to explore the effect and underlying mechanism of SQS in the treatment of prostate cancer (PC).

Materials and methods: PC cell lines (22Rv1 and PC-3) were treated with SQS (0, 0.5, 1, 2, and 4 μM) for 12 or 24 h. The viability of cells was evaluated, while the mRNA and protein levels of epithelial to mesenchymal transition (EMT)-related genes in PC cell lines were measured (Groups: Control, TGF-β1, TNF-α, TGF-β1 + TNF-α, and TGF-β1 + TNF-α + SQS). The migration and invasion abilities of PC cell lines were evaluated (Groups: Control, SQS). Finally, the antitumour effect of SQS (25, 50,100, and 200 mg/kg) in BALB/c nude mice (6 weeks, 18-20 g) was evaluated (Groups: Control, Vehicle, 25, 50,100, and 200 mg/kg SQS). The study duration was 1 month.

Results: SQS inhibited the viability and the number of colonies of 22Rv1 or PC-3 cells. The IC₅₀ of SQS of 12 and 24 h in these two cells was 3.25, 1.82, 4.76, and 4.70 μM, respectively. SQS inhibited the adhesion, migration, and invasion of PC cells. It also inhibited the expression of EMT-related markers of PC cells. The PI3K/Akt/mTOR and Smad2/3 signalling pathways were activated in the process of EMT, and SQS could significantly reduce the activation of the PI3K/Akt/mTOR and Smad2/3 pathways. Finally, SQS inhibited the growth of xenograft tumours in vivo.

Conclusions: SQS inhibited EMT in PC by regulating the PI3K/Akt/mTOR and Smad pathways.