title: Heterotrimerization of the growth factor receptors erbB2, erbB3, and insulin-like growth factor-i receptor in breast cancer cells resistant to herceptin.
abstract: Primary and acquired resistance to the breast cancer drug trastuzumab (Herceptin) is a significant clinical problem. Here, we report enhanced activation of downstream signaling pathways emanating from the growth factor receptors erbB2, erbB3, and insulin-like growth factor-I receptor (IGF-IR) in trastuzumab-resistant breast cancer cells. Interactions between IGF-IR and erbB2 or erbB3 occur exclusively in trastuzumab-resistant cells, where enhanced erbB2-erbB3 interactions are also observed. Moreover, these three receptors form a heterotrimeric complex in resistant cells. erbB3 or IGF-IR knockdown by short hairpin RNA-mediated strategies upregulates p27(kip1), inactivates downstream receptor signaling, and resensitizes resistant cells to trastuzumab. Our findings reveal a heterotrimer complex with a key role in trastuzumab resistance. On the basis of our results, we propose that trastuzumab resistance in breast cancer might be overcome by therapeutic strategies that jointly target erbB3, erbB2, and IGF-IR.
authors.affiliation: Departments of Pathology and Obstetrics and Gynecology, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Huang
authors.forename: Lizhi
authors.initials: L
authors.lastname: Gao
authors.forename: Shuiliang
authors.initials: S
authors.lastname: Wang
authors.forename: James L
authors.initials: JL
authors.lastname: McManaman
authors.forename: Ann D
authors.initials: AD
authors.lastname: Thor
authors.forename: Xiaohe
authors.initials: X
authors.lastname: Yang
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Esteva
authors.forename: Bolin
authors.initials: B
authors.lastname: Liu
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000494:pharmacology; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D050760:Cyclin-Dependent Kinase Inhibitor p27; D019008:Drug Resistance, Neoplasm; D006801:Humans; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D055503:Protein Multimerization; D034622:RNA Interference; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020893:Receptor, ErbB-3 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017526:Receptor, IGF Type 1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000068878:Trastuzumab
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D050760:Cyclin-Dependent Kinase Inhibitor p27; D047908:Intracellular Signaling Peptides and Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases; D020893:Receptor, ErbB-3; D017526:Receptor, IGF Type 1; D000068878:Trastuzumab; C436291:CDKN1B protein, human; C508053:ERBB2 protein, human