Fig. 7.

Signaling pathways in EGF-induced AREG mRNA expression. EGF-induced AREG expression was mediated by the extracellular signal-regulated kinase 1/2 (ERK1/2) in three cell lines, however only partially in the C12 and E10. AREG induction was seemingly mediated through an additional, unknown pathway (denoted “?”) in these cell lines. The two stress MAPKs negatively regulated the EGF-induced AREG expression, p38 in the C12 and E10 cell lines, and JNK in the D2 and E10 cell lines. Additionally, EGF-induced AREG expression was negatively regulated by PI3K in all three cell lines