Fig. 5: Inhibition of ERK1/2 signaling augments EGF-induced apoptosis in metastatic breast cancer cells. | Cell Death & Disease

Fig. 5: Inhibition of ERK1/2 signaling augments EGF-induced apoptosis in metastatic breast cancer cells.

From: Biased signaling downstream of epidermal growth factor receptor regulates proliferative versus apoptotic response to ligand

Fig. 5

a Lung metastatic (NME-LM1) cells were pretreated with trametinib, gefitinib, or a nuclear localization sequence-gefitinib conjugate (NLS-GEF) and then stimulated with EGF (50 ng/ml) for 30 min. These cells were subsequently analyzed for phosphorylation of STAT1 and ERK1/2. IL6 and BSA (0) served as protein stimulation controls and total levels of STAT1 and ERK1/2 were assessed as loading controls. b NME-LM1 cells were stimulated with EGF (100 ng/ml) in the presence or absence of trametinib (Tram), gefitinib (GEF), or the nuclear localization sequence-gefitinib conjugate (NLS-GEF). Following 24 h of treatment, these cells were assayed for caspase 3/7 activity. (Inset) Representative images of cells under control and Tram/EGF stimulation are shown. c As in panel b, NME-LM1 cells were stimulated with EGF (50 ng/ml) in the presence of the indicated inhibitors for 5 days at which point changes in cellular viability were quantified. d NME-LM1 cells were stimulated as indicated for 3 days at which point cell viability was quantified. e NME-LM1 tumorspheres were formed in round bottom wells and subsequently transferred to a hydrogel layer of basement membrane in the presence or absence of EGF and trametinib. Tips of invading cellular branches were quantified. Data in panels b–e are the mean ± SE of three independent experiments completed in triplicate

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