Hypoxia enhances cancer development in a solid tumor. Hypoxia-inducible factor-1 á (HIF-1á) is a transcription factor that is dominantly expressed under hypoxia in solid tumor cells and is a key factor that regulates tumor. HIF-1á regulates several target genes involved in many aspects of cancer progression, including angiogenesis, metastasis, anti-apoptosis and cell proliferation as well as imparts resistance to cancer treatment. In this study, we assessed Crataegus Pinnatifida Bunge var. typical Schneider ethanol extract (CPE) for its anti-cancer effects in hypoxia-induced DU145 human prostate cancer cell line. CPE decreased the abundance of HIF-1á and sphingosine kinase-1 (SPHK-1) in hypoxia-induced prostate cancer DU145 cells. CPE decreased HIF-1á and SPHK-1 as well as SPHK-1 activity. Chlorogenic acid (CA) is one of four major compounds of CPE. Compared to CPE, CA significantly decreased the expression of HIF-1á and SPHK-1 as well as SPHK-1 activity in hypoxia-induced DU145 cells. Furthermore, CA decreased phosphorylation AKT and GSK-3â, which are associated with HIF-1á stabilization and affected SPHK-1 in a concentration-dependent manner. We confirmed the mechanism of CA-induced inhibition of HIF-1á by SPHK-1 signaling pathway using SPHK-1 siRNA and SPHK inhibitor (SKI). CA decreased the secretion and cellular expression of VEGF, thus inhibiting hypoxia-induced angiogenesis. Treatment of DU145cells with SPHK1 siRNA and CA for 48 h decreased cancer cell growth, and the inhibitory action of SPHK siRNA and CA on cell growth was confirmed by decrease in the abundance of Proliferating cell nuclear antigen (PCNA).
Cell Line, Tumor Cell Proliferation