title: Noninvasive imaging and quantification of epidermal growth factor receptor kinase activation in vivo.
abstract: Epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase (RTK) critical in tumor growth and a major target for anticancer drug development. However, thus far, there is no effective system to monitor its activities in vivo. Here, we report a novel approach to monitor EGFR activation based on the bifragment luciferase reconstitution system. The EGFR receptor and its interacting partner proteins (EGFR, growth factor receptor binding protein 2, and Src homology 2 domain-containing) were fused to NH(2) terminal and COOH terminal fragments of the firefly luciferase. After establishing tumor xenograft from cells transduced with the reporter genes, we show that the activation of EGFR and its downstream factors could be quantified through optical imaging of reconstituted luciferase. Changes in EGFR activation could be visualized after radiotherapy or EGFR inhibitor treatment. Rapid and sustained radiation-induced EGFR activation and inhibitor-mediated signal suppression were observed in the same xenograft tumors over a period of weeks. Our data therefore suggest a new methodology where activities of RTKs can be imaged and quantified optically in mice. This approach should be generally applicable to study biological regulation of RTK, as well as to develop and evaluate novel RTK-targeted therapeutics.
authors.affiliation: Department of Radiation Oncology, University of Colorado Health Sciences Center, Aurora, Colorado 80010, USA.
authors.forename: Wenrong
authors.initials: W
authors.lastname: Li
authors.forename: Fang
authors.initials: F
authors.lastname: Li
authors.forename: Qian
authors.initials: Q
authors.lastname: Huang
authors.forename: Barbara
authors.initials: B
authors.lastname: Frederick
authors.forename: Shideng
authors.initials: S
authors.lastname: Bao
authors.forename: Chuan-Yuan
authors.initials: CY
authors.lastname: Li
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis / Q000188:drug therapy* / Q000378:metabolism / Q000532:radiotherapy; D003952:Diagnostic Imaging / Q000379:methods*; D016503:Drug Delivery Systems / Q000379:methods; D004789:Enzyme Activation / Q000187:drug effects; D066246:ErbB Receptors / Q000032:analysis / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D005260:Female; D051380:GRB2 Adaptor Protein / Q000235:genetics / Q000378:metabolism; D017930:Genes, Reporter; D045325:HCT116 Cells; D006801:Humans; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008175:Lung Neoplasms / Q000175:diagnosis / Q000188:drug therapy* / Q000378:metabolism / Q000532:radiotherapy; D051379:Mice; D008819:Mice, Nude; D008954:Models, Biological; D047428:Protein Kinase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D016896:Treatment Outcome; D023041:Xenograft Model Antitumor Assays
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000970:Antineoplastic Agents; D051380:GRB2 Adaptor Protein; D047428:Protein Kinase Inhibitors; D011993:Recombinant Fusion Proteins; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; C528034:Shc1 protein, mouse; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D008156:Luciferases; D066246:ErbB Receptors