Epidermal growth factor (EGF) suppresses staurosporine-induced apoptosis by inducing mcl-1 via the mitogen-activated protein kinase pathway

CM Leu, C Chang, C Hu - Oncogene, 2000 - nature.com
CM Leu, C Chang, C Hu
Oncogene, 2000nature.com
Overexpression of epidermal growth factor receptor (EGFR) and establishment of
transforming growth factor α (TGF α)/EGF autocrine system are frequently detected in tumor
cells. In addition to mitogenic ability, we demonstrate in this report that EGF protects a
human esophageal carcinoma (CE) cell line, CE81T/VGH, from staurosporine-induced
apoptosis. The anti-apoptotic signal of EGF is alleviated by a MEK inhibitor PK98059 or an
ERK2 dominant negative mutant but not by a phosphatidylinositol-3′-kinase (PI-3K) …
Abstract
Overexpression of epidermal growth factor receptor (EGFR) and establishment of transforming growth factor α (TGF α)/EGF autocrine system are frequently detected in tumor cells. In addition to mitogenic ability, we demonstrate in this report that EGF protects a human esophageal carcinoma (CE) cell line, CE81T/VGH, from staurosporine-induced apoptosis. The anti-apoptotic signal of EGF is alleviated by a MEK inhibitor PK98059 or an ERK2 dominant negative mutant but not by a phosphatidylinositol-3′-kinase (PI-3K) inhibitor wortmannin. Furthermore, v-raf blocks apoptosis induced by staurosporine. This evidence implies that the survival signal of EGF is mediated via the Raf-MEK-ERK pathway but not the PI3-K pathway. The survival effect of EGF is coincident with the induction of mcl-1, an anti-apoptotic gene in the bcl-2 family. PD98059 also suppresses the induction of Mcl-1 by EGF, implying that EGF may up-regulate Mcl-1 via the MAP kinase pathway. Overexpression of mcl-1 is sufficient to protect against apoptosis, while transfection of a mcl-1 antisense plasmid causes cell death. The expression of mcl-1 antisense plasmid also suppresses the anti-apoptotic effect of EGF. Taken together, these results indicate that EGF may up-regulate Mcl-1 through the MAP kinase pathway to suppress apoptosis.
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