RAPGEF3 and ovarian adenocarcinoma: To test whether the formation of nuclear structures could be recapitulated by endogenous EPAC1, we used two different cell models, Human Umbilical Vein Endothelial Cells (HUVEC) and an ovary adenocarcinoma cell line (SKOV3) both expressing endogenous EPAC1 in the nucleus as confirmed by nuclear fractionation and Western Blotting (Fig. 1d).