EGFR participates downstream of ERα in estradiol-17β-d-glucuronide-induced impairment of Abcc2 function in isolated rat hepatocyte couplets

BAROSSO, ISMAEL R.; BOAGLIO, ANDREA C; CROCENZI, FERNANDO A.; MISZCZUK, GISEL SABRINA; ROMA, MARCELO G; ZUCCHETTI, ANDRéS ERNESTO; TABORDA, DIEGO; SáNCHEZ POZZI, ENRIQUE J

ARCHIVES OF TOXICOLOGY.

SPRINGER

Lugar: Berlin; Año: 2016 vol. 90 p. 891 - 903

0340-5761

Abstract Estradiol-17â-d-glucuronide (E17G) induces acute endocytic internalization of canalicular transporters, including multidrug resistance-associated protein 2 (Abcc2) in rat, generating cholestasis. Several proteins organized in at least two different signaling pathways are involved inE17G cholestasis: one pathway involves estrogen receptor alpha (ERá), Ca2+-dependent protein kinase C and p38-mitogen activated protein kinase, and the other pathway involves GPR30, PKA, phosphoinositide 3-kinase/AKT and extracellular signal-related kinase 1/2. EGF receptor (EGFR) can potentially participate in both pathways since it interacts with GPR30 and ERá. Hence, the aim of this study was to analyze the potential role of this receptor and its downstream effectors, members of the Src family kinases in E17G-induced cholestasis. In vitro, EGFR inhibition by Tyrphostin (Tyr), Cl-387785 or its knockdown with siRNA strongly prevented E17G-induced impairment of Abcc2 function and localization. Activation of EGFR was necessarybut not sufficient to impair the canalicular transporter function, whereas the simultaneous activation of EGFR and GPR30 could impair Abcc2 transport. The protection of Tyr was not additive to that produced by the ERá inhibitor ICI neither with that produced by Src kinase inhibitors, suggestingthat EGFR shared the signaling pathway of ERá and Src. Further analysis of ERá, EGFR and Src activations inducedby E17G, demonstrated that ERá activation precedes that of EGFR and EGFR activation precedes that of Src. In conclusion, activation of EGFR is a key factor in the alteration of canalicular transporter function and localization induced by E17G and it occurs before that of Src and after that of ERá.