2-bromo-2',5'-dihydroxychalcone analogue Inhibits Endothelial Migration by Targeting VEGF-induced ERK 1/2 Phosphorylation

Abstract

Angiogenesis, the process of new blood vessel formation, is characterized by three essential hallmarks: endothelial proliferation, migration, and differentiation. Each is integral in angiogenesis related diseases, especially cancer. With drug efficacy stagnated due to acquired drug resistance and off target side effects, the need for combinatorial therapy is ever more present. To identify new compounds that could aid current antiangiogenic therapies, we report the preliminary mechanistic evaluation of a 2-bromo-25-dihydroxychalcone analogue and its antimigratory effects on endothelial cells. After the synthesis and validation of the 2-bromo-25-dihydroxychalcone analogue (AH9), its effect was tested in vitro using human umbilical vein endothelial cells (HUVEC). Initial investigations into 2-bromo-25-dihydroxychalcone effect in vitro was conducted with a cell proliferation assay including MTT, afterward endothelial migration was measured with the scratch assay in subsequent functional studies. For mechanistic evaluation, vascular endothelial growth factor (VEGF) induced ERK phosphorylation using western blot was implemented. AH9 inhibited VEGF-induced ERK [1/2] phosphorylation similar to that of known antiangiogenic drug Sorafenib at all three concentrations 100 M (46%, p = 0.003), 30 M (64%, p = 0.0002) and 10 M (91%, p = 0.0001). In a scratch assay model, whilst sorafenib at 3 M was not able to limit migration after 8-hr compared to an untreated control (p = 0.0978), AH9 did (17.41%, p = 0.0079). Furthermore, AH9 was able to inhibit ERK [1/2] phosphorylation in a concentration dependent manner 100 M (46%, p = 0.003), 30 M (64%, p = 0.0002) and 10 M (91%, p = 0.0001) compared to the VEGF control. These preliminary findings support that AH9 could be exerting antimigratory effects through the inhibition of the VEGF induced MAPK/ERK pathway. This forms the foundation for further studies to explore chalcone analogues in hope to aid current antiangiogenic therapeutic strategies as potential angiogenic inhibitors.