AUTHOR=Lin Wanfu , Li Shu , Meng Yongbin , Huang Guokai , Liang Shufang , Du Juan , Liu Qun , Cheng Binbin 

TITLE=UDCA Inhibits Hypoxic Hepatocellular Carcinoma Cell–Induced Angiogenesis Through Suppressing HIF-1α/VEGF/IL-8 Intercellular Signaling

JOURNAL=Frontiers in Pharmacology

VOLUME=Volume 12 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2021.755394

DOI=10.3389/fphar.2021.755394

ISSN=1663-9812

ABSTRACT=Background: Hypoxic microenvironment may induce angiogenesis and promote the development of hepatocellular carcinoma (HCC). The aim of this study was to evaluate whether Ursodeoxycholic acid (UDCA) may inhibit hypoxic HCC cells-induced angiogenesis and the possible mechanisms. 
Methods: Tube formation and Matrigel plug angiogenesis assays were used to evaluate angiogenesis in vitro and in vivo, respectively. Real-time PCR, enzyme-linked immunosorbent assay and western blot were used to evaluate the mRNA and protein expressions of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and IL-8, respectively. Dual luciferase reporter assay was applied to assess the reporter gene expression of hypoxia-response-element (HRE).
Results: UDCA antagonized hypoxic Huh 7 cells-induced tube formation of EA.hy 926 cells. In HCC cells, UDCA inhibited hypoxia-induced up-regulation of VEGF and IL-8 both in mRNA and protein levels. UDCA also inhibited IL-8-induced angiogenesis in vitro and in vivo through suppressing IL-8-induced phosphorylation of ERK. The levels of HIF-1α mRNA and protein and HRE-driven luciferase activity in HCC cells were up-regulated by hypoxia and were all inhibited by UDCA. The proteasome inhibitor MG132 antagonized the effect of UDCA on HIF-1α degradation. In hypoxic condition, the phosphorylation of ERK and AKT was obviously increased in HCC cells, which was suppressed by UDCA. Transfection of the HIF-1α overexpression plasmid reversed the effects of UDCA on hypoxic HCC cells-induced angiogenesis, HRE activity, and expression of IL-8 and VEGF.
Conclusions: Our results demonstrated that UDCA could inhibit hypoxic HCC cells-induced angiogenesis through suppressing HIF-1α/VEGF/IL-8 mediated intercellular signaling between HCC cells and endothelial cells.