Diosgenin inhibits tumor angiogenesis through regulating GRP78-mediated HIF-1α and VEGF/VEGFR signaling pathways.

The present paper describes the molecular mechanism of diosgenin on tumor microenvironment angiogenesis and the regulation of GRP78 in angiogenesis signaling pathway. CCK8 method was used to evaluate the effect of different concentrations of diosgenin on HUVEC activity in hypoxic microenvironment. Apoptosis was detected by Annexin V/PI staining. Tube Formation experiment was conducted to evaluate angiogenesis. Western Blot assay was applied to detect the expressions and phosphorylation levels of the angiogenesis-related pathways HIF-1 alpha, GRP78, VEGF/VEGFR, PI3K/AKT, ERK, and FAK in rheumatoid HUVEC. Silencing GRP78 by siRNA interference technology was employed to investigate the mechanism of GRP78 involved in the regulation of angiogenesis. The results indicated that diosgenin can significantly inhibit the cell viability of hypoxic HUVEC and the significance is dependent on drug concentration. As the concentration increases, HUVEC activity decreases. Cell apoptosis is induced in a dose-dependent manner and angiogenesis can be significantly inhibited. The hypoxic microenvironment can significantly increase the expressions of HIF-1 alpha, GRP78, VEGF/VEGFR, PI3K/AKT, ERK, FAK proteins in angiogenesis-related pathways, and can also enhance the phosphorylation of AKT, ERK1/2 and FAK proteins, which can be decreased by drug intervention. After silencing GRP78, the angiogenesis-related pathway proteins HIF-1 alpha and VEGF/VEGFR are significantly reduced, thus inhibiting the activation of AKT, ERK1/2, and FAK. The anti-tumor angiogenesis mechanism of diosgenin inhibiting the expression of HIF-1 alpha, GRP78, VEGF/VEGFR, PI3K/AKT, ERK1/2 and FAK signaling pathways may be through multiple pathways and targets, and GRP78 is involved in the regulation of angiogenesis signaling pathway.