title: Elevation of receptor tyrosine kinase EphA2 mediates resistance to trastuzumab therapy.
abstract: One arising challenge in the treatment of breast cancer is the development of therapeutic resistance to trastuzumab, an antibody targeting the human epidermal growth factor receptor-2 (HER2), which is frequently amplified in breast cancers. In this study, we provide evidence that elevated level of the receptor tyrosine kinase Eph receptor A2 (EphA2) is an important contributor to trastuzumab resistance. In a screen of a large cohort of human breast cancers, we found that EphA2 overexpression correlated with a decrease in disease-free and overall survival of HER2-overexpressing patients. Trastuzumab-resistant cell lines overexpressed EphA2, whereas inhibiting EphA2 restored sensitivity to trastuzumab treatment in vivo. Notably, trastuzumab treatment could promote EphA2 phosphorylation by activating Src kinase, leading in turn to an amplification of phosphoinositide 3-kinase/Akt and mitogen-activated protein kinase signaling in resistant cells. Our findings offer mechanistic insights into the basis for trastuzumab resistance and rationalize strategies to target EphA2 as a tactic to reverse trastuzumab resistance.
authors.affiliation: Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tenessee 37232, USA.
authors.forename: Guanglei
authors.initials: G
authors.lastname: Zhuang
authors.forename: Dana M
authors.initials: DM
authors.lastname: Brantley-Sieders
authors.forename: David
authors.initials: D
authors.lastname: Vaught
authors.forename: Jian
authors.initials: J
authors.lastname: Yu
authors.forename: Lu
authors.initials: L
authors.lastname: Xie
authors.forename: Sam
authors.initials: S
authors.lastname: Wells
authors.forename: Dowdy
authors.initials: D
authors.lastname: Jackson
authors.forename: Rebecca
authors.initials: R
authors.lastname: Muraoka-Cook
authors.forename: Carlos
authors.initials: C
authors.lastname: Arteaga
authors.forename: Jin
authors.initials: J
authors.lastname: Chen
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005260:Female; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D036104:Receptor, EphA2 / Q000096:biosynthesis* / Q000235:genetics; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D016019:Survival Analysis; D000068878:Trastuzumab; D023041:Xenograft Model Antitumor Assays; D019061:src-Family Kinases / Q000187:drug effects / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D036104:Receptor, EphA2; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; D019061:src-Family Kinases; C508053:ERBB2 protein, human