Inhibition Effect and Mechanism of YSY-01A,a Novel Proteasome Inhibitor,on Tumor-induced Angiogenesis

Compound YSY-01A is a recently synthesized proteasome inhibitor.It has been proved for potent growth-inhibitory effect on tumor cells in previous studies.However,the effect of YSY-01A on tumor angiogenesis remains unclear.Our research aims to reveal the inhibition effect and mechanism of YSY-01A on tumor-induced angiogenesis.Firstly,we combined the Sulforhodamine B(SRB) assay and Transwell co-culture model to observe the inhibition of YSY-01A on human umbilical vein endothelial cells(HUVECs) proliferation induced by tumor cells(HT-29 cells).In succession,high content screening(HCS) assay was used to investigate effect of YSY-01A on NF-κB nuclear translocation in HT-29 cells.Finally,Western blot was used to measure the expression of hypoxia-inducible factor-1α(HIF-1α) and vascular endothelial growth factor(VEGF) in HT-29 cells inhibited by YSY-01A.To further determine mechanism of inhibition,SRB and HCS methods were used to investigate the effect of YSY-01A against HUVECs proliferation and motility,respectively.The results showed that YSY-01A could prohibit HUVECs proliferation induced by HT-29 cells in a concentration-dependent manner.Furthermore,YSY-01A significantly inhibited NF-κB nuclear translocation and reduced the expression of HIF-1α and VEGF in HT-29 cells.Further investigation revealed concentration-dependent suppress of YSY-01A on HUVECs proliferation and motility without obvious cytotoxic effect.In conclusion,through proteasome inhibition,YSY-01A could down-regulate pro-angiogenesis factors expression in tumor cells and exhibit remarkable anti-angiogenesis activity on vascular endothelial cells.