Altered Egfr Localization and Degradation in Human Breast Cancer Cells with an Amphiregulin/Egfr Autocrine Loop
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Cell Signal. Author manuscript; available in PMC 2010 February 1.
Published in final edited form as: Cell Signal. 2009 February ; 21(2): 212–219. doi:10.1016/j.cellsig.2008.10.003.
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Altered EGFR Localization and Degradation in Human Breast Cancer Cells with an Amphiregulin/EGFR Autocrine Loop
Nicole E. Willmartha,b, Andrea Baillob, Michele L. Dziubinskib, Kristy Wilsonc, David J. Riese IIc, and Stephen P. Ethierb,1 a Department of Cancer Biology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, PA, USA 19107 b Breast Cancer Program, Karmanos Cancer Institute, Department of Pathology, Wayne State University School of Medicine, Detroit, MI, USA 48201 and c Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA 47907
Abstract
The epidermal growth factor receptor (EGFR) and its ligand amphiregulin (AR) have been shown to be co-over expressed in breast cancer. We have previously shown that an AR/EGFR autocrine loop is required for SUM149 human breast cancer cell proliferation, motility and invasion. We also demonstrated that AR can induce these altered phenotypes when expressed in the normal mammary epithelial cell line MCF10A, or by exposure of these cells to AR in the medium. In the present studies, we demonstrate that SUM149 cells and immortalized human mammary epithelial MCF10A cells that over express AR (MCF10A AR) or are cultured in the presence of exogenous AR, express higher levels of EGFR protein than MCF10A cells cultured in EGF. Pulse chase analysis showed that EGFR protein remained stable in the presence of AR, yet was degraded in the presence of EGF. Consistent with this observation, tyrosine 1045 on the EGFR, the c-cbl binding site, exhibited less phosphorylation following stimulation with AR than following stimulation with EGF. Ubiquitination of the receptor was
Author Manuscript
Cell Signal. Author manuscript; available in PMC 2010 February 1.
Published in final edited form as: Cell Signal. 2009 February ; 21(2): 212–219. doi:10.1016/j.cellsig.2008.10.003.
NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author Manuscript
Altered EGFR Localization and Degradation in Human Breast Cancer Cells with an Amphiregulin/EGFR Autocrine Loop
Nicole E. Willmartha,b, Andrea Baillob, Michele L. Dziubinskib, Kristy Wilsonc, David J. Riese IIc, and Stephen P. Ethierb,1 a Department of Cancer Biology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, PA, USA 19107 b Breast Cancer Program, Karmanos Cancer Institute, Department of Pathology, Wayne State University School of Medicine, Detroit, MI, USA 48201 and c Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA 47907
Abstract
The epidermal growth factor receptor (EGFR) and its ligand amphiregulin (AR) have been shown to be co-over expressed in breast cancer. We have previously shown that an AR/EGFR autocrine loop is required for SUM149 human breast cancer cell proliferation, motility and invasion. We also demonstrated that AR can induce these altered phenotypes when expressed in the normal mammary epithelial cell line MCF10A, or by exposure of these cells to AR in the medium. In the present studies, we demonstrate that SUM149 cells and immortalized human mammary epithelial MCF10A cells that over express AR (MCF10A AR) or are cultured in the presence of exogenous AR, express higher levels of EGFR protein than MCF10A cells cultured in EGF. Pulse chase analysis showed that EGFR protein remained stable in the presence of AR, yet was degraded in the presence of EGF. Consistent with this observation, tyrosine 1045 on the EGFR, the c-cbl binding site, exhibited less phosphorylation following stimulation with AR than following stimulation with EGF. Ubiquitination of the receptor was