HUVEC proliferation assays

5-Ethynyl-2′-deoxyuridine (EdU) is a thymidine analogue that is incorporated into replicating DNA when cells are dividing and is used to label proliferating cells. HUVECs were trypsinized, counted, and seeded onto 96-well plates at a density of 1 × 10⁴cells/well. HUVECs were grown to 80% confluence and were pretreated with or without JQ1 (100 nmol/L) for 6 h prior to incubation without or with VEGF for 24 h. Cell proliferation was then measured using a Cell-Light EdU DNA Cell Proliferation Kit according to the manufacturer’s instructions. Each assay was replicated 3 times.