Molecular Mechanisms Of Myricetin Reverses Epithelial-endothelial Transition And Inhibits Vasculogenic Mimicry Of Hepatocellular Carcinoma By Directly Targeting PAR1

Most anti-angiogenic inhibitors targeting endothelium-dependent vessels can not inhibit tumor growth in some patients,but promote tumor invasion and metastasis in some cases.Inhibition of tumor angiogenesis will be a new research direction of tumor angiogenesis.Vasculogenic mimicry(VM),a functional microcirculation pattern in malignant tumors,has different mechanisms from endothelium-dependent vessels.VM is induced by tumor cells by hypoxia and other factors,the tumor cells by epithelial phenotype into endothelial phenotype,to form similar to the vascular channels,main effect is to provide oxygen and other nutrients for the tumor.Inhibit VM may be a novel anti-angiogenic strategy.In this paper,the antagonistic effect on PAR1 activation of several antitumor flavonoids compounds,were evaluated by Ca mobilization analysis,Myricetin exhibited the best antagonistic effect.In two different hepatocellular carcinoma(HCC)cell lines,Myricetin inhibited cell migration,VM formation and change the expression of epithelial-endothelial transition(EET)markers,up-regulated E-cadherin expression,and down-regulated VEGFR1/2 expression in a dose-dependent manner by inhibit PAR1 activation.Docking assay revealed that Myricetin bind to Leu258 and Thr261 in PAR1 activity pocket.Mutant Leu258 and Thr261 inhibited the anti-tumor effect of Myricetin in vitro and vivo.In summary,Myricetin inhibits invasion,metastasis and VM formation of HCC cells through directly targeting PAR1 Leu258 and Thr261 and reverse PAR1-mediated EET.In summary,this study aims to investigate the molecular mechanism of myricetin targeting PAR1 in inhibiting tumor VM formation.The inhibitory effect of myricetin on the formation of VM was studied by cell function experiment in vitro and animal experiment in vivo.Through the establishment of PAR1 knockout system and point mutation system,the anti-tumor target of myricetin was further confirmed.