Dual blockade of VEGFR1 and VEGFR2 by a novel peptide abrogates VEGF-driven angiogenesis, tumor growth, and metastasis through PI3K/AKT and MAPK/ERK1/2 pathway

Background: Neutralization of vascular endothelial growth factor receptor 1 (VEGFR1) and/or VEGFR2 is a widely used means of inhibiting tumor angiogenesis. Methods: Based on the complex X-ray structures of VEGFA/VEGFR1, VEGFA/VEGFR2, and VEGFB/VEGFR1, a peptide (referred to as VGB) was designed to simultaneously bind to VEGFR1 and VEGFR2, and binding, antiangiogenic and antitumor properties of the peptide was investigated in vitro. Results: VGB bound to both VEGFR1 and VEGFR2 in human umbilical vein endothelial cells (HUVECs) and 4 T1 mammary carcinoma tumor (MCT) cells, and inhibited the proliferation of HUVE, 4 T1 MCT, and U87 glioblastoma cells. Through abrogation of AKT and ERICl/2 phosphorylation, VEGFA-stimulated proliferation, migration, and two- and three-dimensional tube formation in HUVECs were inhibited more potently by VGB than by bevacizumab. In a murine 4T1 MCT model, VGB strongly inhibited tumor growth without causing weight loss, accompanied by inhibition of AKT and ERK112 phosphorylation, a significant decrease in tumor cell proliferation (Ki-67 expression), angiogenesis (CD31 and CD34 expression), an increase in apoptosis index (increased TUNEL staining and p53 expression and decreased Bc1-2 expression), and the suppression of systematic spreading of the tumor (reduced NF-kappa B and MMP-9 and increased E-cadherin expression). Conclusion: The dual specificity of VGB for VEGFR1 and VEGFR2, through which the PI3K/AKT and MAPK/ERK1/2 signaling pathways can be abrogated and, subsequently, angiogenesis, tumor growth, and metastasis are inhibited. General significance: This study demonstrated that simultaneous blockade of VEGFR1 and VEGFR2 downstream cascades is an effective means for treatment of various angiogenic disorders, especially cancer.