The effect and mechanism of Xihuang pill inhibits the formation of vasculogenic mimicry in human glioblastoma cells by down-regulating HIF-1α/VEGFA/VEGFR2 signaling pathway / 药学学报

ABSTRACT

Our studies were aimed to explore the effect and mechanism of the inhibition of the formation of vasculogenic mimicry (VM) in human glioblastoma cells by Xihuang pill (XHP) medicated serum through regulating the hypoxia inducible factor-1α (HIF-1α)/vascular endothelial growth factor A (VEGFA)/vascular endothelial growth factor receptor 2 (VEGFR2) signaling pathway. The medicated serum of XHP was prepared by gavage for 7 days to male SD rats (approval number of animal experiment ethics 202105A051). The hypoxia model of U251 cells was established using 200 μmol·L-1 of CoCl2. After treatment with XHP-medicated serum, cell viability and proliferation of U251 cells were detected by CCK-8 and cell cloning experiment. Cell apoptosis and cell cycle of U251 cells were determined by flow cytometry. Cell migration and invasion were evaluated by wound healing and Transwell invasion assay. The formation of VM was assessed by three-dimensional cell culture of U251 cells. The protein expression levels of HIF-1α, VEGFA, VEGFR2, phosphorylated-VEGFR2 (p-VEGFR2), vascular endothelial-cadherin (VE-cadherin), Eph receptor tyrosine kinases A2 (EphA2), matrix metalloproteinase 2 (MMP2), matrix metalloproteinase 14 (MMP14) and laminin γ2 in U251 cells were detected by Western blot. The results showed that 10% XHP-medicated serum had little effect on the cell viability, proliferation, apoptosis and cell cycle of U251 cells under hypoxia. Compared with the model group, 10% XHP-medicated serum at 1.0, 1.5 and 2.0 h significantly decreased the migration rate (P < 0.01) and the number of invading U251 cells (P < 0.01). 10% XHP-medicated serum at 2.0 h significantly suppressed the formation of VM tubular structures in U251 cells under the condition of hypoxia (P < 0.01). Western blot experiment showed that 10% XHP-medicated serum significantly down-regulated the expression of HIF-1α, VEGFA, phospho-VEGFR2, VE-cadherin, EphA2 and MMP14 proteins (P < 0.05). In conclusion, XHP could inhibit the formation of VM in human glioblastoma U251 cells to suppress the angiogenesis by down-regulating the HIF-1α/VEGFA/VEGFR2 signaling pathway.