Effects of novel chalcone derivatives on human endothelial cell proliferation and migration

Introduction: Angiogenesis is the formation of new blood vessels from the pre-existing vasculature and is essential for some physiological processes including wound healing and menstrual cycles. Unregulated angiogenesis can lead to vascular related diseases such as age related macular degeneration, cancer and rheumatoid arthritis. Chalcones (1,3-diphenylpropenones) are naturally occurring phenolic compounds found in a variety of plants and fruits. Their simple molecular structures have demonstrated an array of pharmacological activity including antioxidant and anti-vascular. Due to Chalcones having an easily modifiable scaffold, they are widely used as parent compounds in drug discovery studies. Endothelial cell proliferation and migration are essential for angiogenic growth, so compounds that possess anti-endothelial activity could be developed further as potential inhibitors of angiogenesis. With this in mind, we report the anti-endothelial activity of two novel analogues (AH1 and AH9) derived from the parent compound 2-chloro-2’5’-dihydroxychalcone.

Method: Chalcones were synthesised via the Claisen-Schmidt condensation and verified via nuclear magnetic resonance (NMR) and mass spectrometry (MS). Primary Human umbilical vein endothelial cells (HUVECs) were cultured according to manufactures protocol. Cells were seeding into 96-well plates (3500 cells/well) and, 24 hours later, treated either with AH1, AH9 or Sorafenib, a known anti-angiogenic drug for 72hr at a concentration of 10 µM. Effects of the compounds on cell proliferation was assessed by quantifying the colorimetric conversion of 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) to purple formazan product (measured at 560 nm). Data are expressed as mean % inhibition of cell proliferation ± SEM (n=4). Anti-migratory activity was assessed via the wound healing assay and the effects of the compounds at 3 µM on the width of the scratch across an 8 hour period were compared to untreated control. Analysis was performed by one-way ANOVA with Tukey-Kramer’s multiple comparisons test. Data are expressed as mean % of maximum migration ± SEM (n=3).

Results: AH1 and AH9 displayed significant anti-proliferative activity with inhibitory values of 94.94 ± 1.64% and 79.62 ± 4.45% compared to Sorafenib, 69.95 ± 4.12%, respectively. Effects on HUVEC migration showed that AH9 limited migration to 16.19 ± 14.44% (P<0.05 vs. control). AH1 (47.23 ± 6.8%) showed similar anti-migratory activity to Sorafenib (52.68 ± 3.32%).

Conclusion: This preliminary data suggests that AH9 has potential antiangiogenic properties and could be developed further as a potential antiangiogenic or vascular remodelling agent. Further studies will elucidate the molecular mechanism of AH9 action in cells stimulated with known angiogenic agent, VEGF.