scholarly journals sMEK1 inhibits endothelial cell proliferation by attenuating VEGFR-2-dependent-Akt/eNOS/HIF-1α signaling pathways

Oncotarget ◽  
2015 ◽  
Vol 6 (31) ◽  
pp. 31830-31843 ◽  
Author(s):  
Boh-Ram Kim ◽  
Seung Hee Seo ◽  
Mi Sun Park ◽  
Seung-Hoon Lee ◽  
Youngjoo Kwon ◽  
...  
2015 ◽  
Vol 35 (5) ◽  
pp. 1689-1705 ◽  
Author(s):  
Heng Cai ◽  
Yixue Xue ◽  
Zhen Li ◽  
Yi Hu ◽  
Zhenhua Wang ◽  
...  

Background and Aims: Endothelial cell (EC) proliferation, migration, and tube formation are the critical steps for tumor angiogenesis, which is involved in the formation of new tumor blood vessels. Roundabout4 (Robo4), a new member of Robo proteins family, is specifically expressed in endothelial cells. This study aimed to investigate the effects of Robo4 on glioma-induced endothelial cell proliferation, migration and tube formation in vitro. Methods and Results: We found that Robo4 was endogenously expressed in Human Brain Microvascular Endothelial Cells (HBMECs), while Robo4 was significantly down-regulated in endothelial cells cultured in glioma conditioned medium. Robo4 over-expression remarkably suppressed glioma-induced endothelial cell proliferation, migration and tube formation in vitro. In addition, Robo4 influenced the glioma-induced angiogenesis via binding to its ligand Slit2. Further studies demonstrated that the knockdown of Robo4 up-regulated the phosphorylation of VEGFR2, PI3K, AKT and FAK in EC cultured in glioma conditioned medium. VEGFR2 inhibitor SU-1498, AKT inhibitor LY294002 and FAK inhibitor 14 (FAK inhibitor) blocked the Robo4 knockdown-mediated alteration in glioma angiogenesis in vitro. Conclusion: Our results proved that Robo4 suppressed glioma-induced endothelial cell proliferation, migration and tube formation in vitro by inhibiting VEGR2-mediated activation of PI3K/AKT and FAK signaling pathways.


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