Background:

ESI-09 is a specific inhibitor of EPAC with IC50 values of 1.4 and 3.2 μM for EPAC2 and EPAC1, respectively [1].

cAMP/cAMP regulated guanine nucleotide exchange factor (EPAC/cAMP-GEF) is a guanine nucleotide exchange factor for small GTPases Rap1 and Rap2 in response to intracellular cAMP [2].

ESI-09 is a specific EPAC inhibitor. ESI-09 (25 μM) reduced EPAC1 and EPAC2 GEF activity to basal levels in the presence of 25 μM cAMP. In the presence of 25 μM cAMP, ESI-09 inhibited cAMP-mediated EPAC2 and EPAC1 GEF activity with IC50 values of 1.4 and 3.2 μM respectively and exhibited 100 times selectivity than PKA. In the pancreatic cancer cell line AsPC-1, ESI-09 inhibited Akt phosphorylation at T308 and S473 stimulated by 007-AM in a dose dependent way. In pancreatic endocrine β cells, ESI-09 inhibited the increase of insulin secretion stimulated by 007-AM in a dose dependent way. In pancreatic cancer cell lines AsPC-1 and PANC-1, ESI-09 significantly reduced cell migration through the inhibition of EPAC1 [1]. In the presence of 20 μM cAMP, ESI-09 inhibited cAMP-mediated EPAC2 and EPAC1 GEF activity with IC50 values of 4.4 and 10.8 μM, respectively [2].

参考文献:
[1].  Almahariq M, Tsalkova T, Mei FC, et al. A novel EPAC-specific inhibitor suppresses pancreatic cancer cell migration and invasion. Mol Pharmacol, 2013, 83(1): 122-128.
[2].  Zhu Y, Chen H, Boulton S, et al. Biochemical and pharmacological characterizations of ESI-09 based EPAC inhibitors: defining the ESI-09 ""therapeutic window"". Sci Rep, 2015, 5: 9344.