VEGFR-2 kinase domain inhibition as a scaffold for anti-angiogenesis: Validation of the anti-angiogenic effects of carotenoids from Spondias mombin in DMBA model of breast carcinoma in Wistar rats
Damilohun Samuel Metibemu, Oluseyi Adeboye Akinloye, Adio J. Akamo, Jude Ogechukwu Okoye, D. A. Ojo, Eric Morifi, Olaposi Idowu Omotuyi
Abstract
Vascular endothelial growth factor (VEGF) and its receptor-2 (VEGFR-2) mediated tumorigenesis, metastasis, and angiogenesis are the cause of the increased levels of mortality associated with breast cancer and other forms of cancer. Inhibition of VEGF and VEGFR-2 provides a great therapeutic option in the management of cancer. This study employed VEGFR-2 kinase domain inhibition as an anti-angiogenic scaffold and further validate the anti-angiogenic effects of the lead phytochemicals, carotenoids from Spondias mombin in 7, 12-Dimethylbenz[a]anthracene (DMBA) model of breast carcinoma in Wistar rats. Phytochemicals characterized from 6 reported anti-cancer plants were screened against the VEGFR-2 kinase domain. The lead phytochemicals, carotenoids from Spondias mombin were isolated and subjected to Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (LC-ESI-MS) for characterization. The anti-angiogenic potentials of the carotenoid isolates were validated in the DMBA model of breast carcinoma in female Wistar rats through assessment of the expression of anti-angiogenic related mRNAs, histopathological analysis, and molecular docking. Treatment with carotenoid isolates (100 mg/kg and 200 mg/kg) significantly (p < 0.05) downregulated the expression of VEGF, VEGFR, Epidermal Growth Factor Receptor (EGFR), Hypoxia-Inducible Factor-1(HIF-1), and Matrix Metalloproteinase-2 (MMP-2) mRNAs in the mammary tumours, while the expression of Chromodomain Helicase DNA-Binding Protein-1 (CHD-1) mRNA was significantly (p < 0.05) upregulated. DMBA induced comedo and invasive ductal subtypes of breast carcinoma. The binding of astaxanthin, 7,7',8,8'-tetrahydro-β,β-carotene, and beta-carotene-15,15′-epoxide to the ATP binding site led to the DFG-out conformation with binding energies of -8.2 kcal/mol, -10.3 kcal/mol, and -10.5 kcal/mol respectively. Carotenoid isolates demonstrated anti-angiogenic and anti-proliferating potentials via VEGFR-2 kinase domain inhibition.