Evidence for G-quadruplex in the promoter of vegfr-2 and its targeting to inhibit tumor angiogenesis
Salvati E, Zizza P, Rizzo A, Iachettini S, Cingolani C, D\\\'Angelo C, Porru M, Randazzo A, Pagano B, Novellino E, Pisanu ME, Stoppacciaro A, Spinella F, Bagnato A, Gilson E, Leonetti C, Biroccio A
Nucleic Acids Res
Cancer Research/Cell Biology
Cells used in publication:
Endothelial, umbilical vein, human (HUVEC)
Tissue Origin: vein
Tumor angiogenesis is mainly mediated by vascular endothelial growth factor (VEGF), a pro-angiogenic factor produced by cancer cells and active on the endothelium through the VEGF receptor 2 (VEGFR-2). Here we identify a G-rich sequence within the proximal promoter region of vegfr-2, able to form an antiparallel G-quadruplex (G4) structure. This G4 structure can be efficiently stabilized by small molecules with the consequent inhibition of vegfr-2 expression. Functionally, the G4-mediated reduction of VEGFR-2 protein causes a switching off of signaling components that, converging on actin cytoskeleton, regulate the cellular events leading to endothelial cell proliferation, migration and differentiation. As a result of endothelial cell function impairment, angiogenic process is strongly inhibited by G4 ligands both in vitro and in vivo. Interestingly, the G4-mediated antiangiogenic effect seems to recapitulate that observed by using a specific interference RNA against vegfr-2, and it is strongly antagonized by overexpressing the vegfr-2 gene. In conclusion, we describe the evidence for the existence of G4 in the promoter of vegfr-2, whose expression and function can be markedly inhibited by G4 ligands, thereby revealing a new, and so far undescribed, way to block VEGFR-2 as target for anticancer therapy.
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