The effect of vascular endothelial growth factor antagonist peptide on endothelial cells and the inhibition of angiogenesis in breast tumor

Farzaneh Behelgardi, Maryam and Zahri, Saber and Asghari, Seyed Mohsen and Mashayekhi, Farhad (2018) The effect of vascular endothelial growth factor antagonist peptide on endothelial cells and the inhibition of angiogenesis in breast tumor. Doctoral thesis, University of Mohaghegh Ardabili.

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Abstract

Research Aim: The vascular endothelial growth factors secreted by tumors play an important role in vascular permeability and tumor angiogenesis through binding to their receptors on the surface of the endothelial cells. In this study, an antagonist peptide of vascular endothelial growth factor (VEGF) was designed, interfering in the binding of VEGFA and VEGFB to VEGFR1 and VEGFR2, to block the signaling pathways in downstream of both the receptors whereby angiogenesis and tumor growth are inhibited. Research method: To confirm the binding of the designed peptide (VGB4) to VEGFR1 and VEGFR2, the flow cytometry and immunofluorescence microscopy assay were carried out. In order to examine the anti-angiogenic activity of VGB4 peptide, endothelial cell proliferation, migration, and angiogenesis tests were performed on HUVECs. Likewise, using 4T1 mammary carcinoma cell line, as a murine breast cancer model in BALB/c mice, VGB4 delivery potential to tumor was evaluated via in vivo imaging. Then,Anti-tumor potential of different doses of VGB4 was examined by intraperitoneal injection to 4T1 breast tumor-bearing mice.The level of angiogenesis, proliferation and apoptosis markers in VGB4 treated tumors was assessed by immunohistochemistry analysis. For the evaluation of the key signaling molecules as well as metastasis markers in down stream pathways of VEGFR1 and VEGFR2, western blot analysis was used. The effect of VGB4 on the expression level of migration and invasion markers in tumor cells was examined using real time PCR. Findings: VGB4 peptide had the binding ability to both VEGFR1 and VEGFR2 and significantly inhibited endothelial cell proliferation, migration, and angiogenesis. The accumulation potential of VGB4 in tumor tissue was confirmed. In addition, the results of in vivo study revealed that VGB4 administration dose-dependently led to an effective decrease in tumor growth as well as angiogenesis and an increase in apoptosis. Likewise, VGB4 significantly inactivated the signaling pathways related to both VEGFR1 and VEGFR2 in vitro and in vivo. The anti-metastatic potential of VGB4 was also verifiedin 4T1 breast tumor samples. Conclusion: Given the significant antagonistic effects of VGB4 on the suppression of angiogenesis and tumor growth, this peptide can be considered as a suitable candidate for cancer therapy.

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