title: Epidermal growth factor receptor pathway analysis identifies amphiregulin as a key factor for cisplatin resistance of human breast cancer cells.
abstract: The use of platinum complexes for the therapy of breast cancer is an emerging new treatment modality. To gain insight into the mechanisms underlying cisplatin resistance in breast cancer, we used estrogen receptor-positive MCF-7 cells as a model system. We generated cisplatin-resistant MCF-7 cells and determined the functional status of epidermal growth factor receptor (EGFR), MAPK, and AKT signaling pathways by phosphoreceptor tyrosine kinase and phospho-MAPK arrays. The cisplatin-resistant MCF-7 cells are characterized by increased EGFR phosphorylation, high levels of AKT1 kinase activity, and ERK1 phosphorylation. In contrast, the JNK and p38 MAPK modules of the MAPK signaling pathway were inactive. These conditions were associated with inactivation of the p53 pathway and increased BCL-2 expression. We investigated the expression of genes encoding the ligands for the ERBB signaling cascade and found a selective up-regulation of amphiregulin expression, which occurred at later stages of cisplatin resistance development. Amphiregulin is a specific ligand of the EGFR (ERBB1) and a potent mitogen for epithelial cells. After exposure to cisplatin, the resistant MCF-7 cells secreted amphiregulin protein over extended periods of time, and knockdown of amphiregulin expression by specific short interfering RNA resulted in a nearly complete reversion of the resistant phenotype. To demonstrate the generality and importance of our findings, we examined amphiregulin expression and cisplatin resistance in a variety of human breast cancer cell lines and found a highly significant correlation. In contrast, amphiregulin levels did not significantly correlate with cisplatin resistance in a panel of lung cancer cell lines. We have thus identified a novel function of amphiregulin for cisplatin resistance in human breast cancer cells.
authors.affiliation: Stiftung Center of Advanced European Studies and Research, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
authors.forename: Niels
authors.initials: N
authors.lastname: Eckstein
authors.forename: Kati
authors.initials: K
authors.lastname: Servan
authors.forename: Luc
authors.initials: L
authors.lastname: Girard
authors.forename: Di
authors.initials: D
authors.lastname: Cai
authors.forename: Georg
authors.initials: G
authors.lastname: von Jonquieres
authors.forename: Ulrich
authors.initials: U
authors.lastname: Jaehde
authors.forename: Matthias U
authors.initials: MU
authors.lastname: Kassack
authors.forename: Adi F
authors.initials: AF
authors.lastname: Gazdar
authors.forename: John D
authors.initials: JD
authors.lastname: Minna
authors.forename: Hans-Dieter
authors.initials: HD
authors.lastname: Royer
mesh_terms: D066258:Amphiregulin; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001943:Breast Neoplasms; D001973:Bromodeoxyuridine / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm; D066255:EGF Family of Proteins; D004797:Enzyme-Linked Immunosorbent Assay; D066246:ErbB Receptors / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006023:Glycoproteins / Q000502:physiology*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000502:physiology*; D009361:Neoplasm Invasiveness; D010766:Phosphorylation; D011494:Protein Kinases / Q000187:drug effects / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
chemical_list: C587848:AREG protein, human; D066258:Amphiregulin; D000970:Antineoplastic Agents; D066255:EGF Family of Proteins; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D011494:Protein Kinases; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt; D001973:Bromodeoxyuridine; D002945:Cisplatin