CE3F4 has been used as a selective exchange protein directly activated by cAMP isoform 1 (Epac1) inhibitor in cell proliferation assay to study the influence of Epac type I on cell proliferation of C6 cells (a model of glioma).

CE3F4 is a tetrahydroquinoline derivative that blocks agonist-stimulated Epac1 (exchange protein directly activated by cAMP isoform 1) guanine nucleotide exchange activity toward its effector Rap1 (IC50 = 23 μM; Epac agonist = 2 μM 8-CPT-2′-O-Me-cAMP) by targeting agonist-bound Epac1 in an agonist-uncompetitive manner without affecting the GDP exchange on Rap1, Rap1-Epac1 interaction, or PKA type I/II activity (CβRIβ & CαRIIβ). CE3F4 (20 μM) effectively inhbits cellular Rap1 activation upon 10 μM Sp-8-pCPT-2′-O-Me-cAMPS (Epac1-transfected HEK293 and rat neonatal cardiac myocytes) or 10 μM β-adrenergic receptor agonist isoprenaline stimulation (β1AR & Epac1 dually transfected HEK293). The isolated CE3F4 R enantiomer is reported to display 10-fold Epac1 selectivity over Epac2, and is 10-times more potent than the CE3F S enantiomer against Epac1.

Epac1 is a downstream effector of the cyclic adenosine monophosphate (cAMP) pathway.

Uncompetitive inhibitor against agonist-induced Epac1 (exchange protein directly activated by cAMP isoform 1) guanine nucleotide exchange activity.