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Updated: Jul 4, 2026
Validated Immunochemical Assay for Comprehensive Determination of the Human Epidermal Growth Factor Receptor 2 Released from and Bound to Cells
Published on: May 9, 2025
Noninvasive imaging and quantification of epidermal growth factor receptor kinase activation in vivo
Wenrong Li1, Fang Li, Qian Huang
1Department of Radiation Oncology, University of Colorado Health Sciences Center, Aurora, Colorado 80010, USA.
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.
Insights
This study introduces a novel bifragment luciferase system to monitor epidermal growth factor receptor (EGFR) activity in vivo. This imaging approach allows for real-time quantification of EGFR activation and its downstream signaling in tumors.
Area of Science:
- Biochemistry
- Molecular Biology
- Oncology
Background:
- Epidermal growth factor receptor (EGFR) is a key receptor tyrosine kinase (RTK) driving tumor growth.
- EGFR is a significant target for anticancer drug development.
- Effective in vivo monitoring systems for EGFR activity are currently lacking.
Purpose of the Study:
- To develop a novel in vivo monitoring system for EGFR activation.
- To quantify EGFR activity and downstream signaling using optical imaging.
- To evaluate the potential of this system for studying RTK biology and drug development.
Main Methods:
- Utilized a bifragment luciferase complementation assay.
- Fused EGFR and interacting proteins (GRB2, SHC) to luciferase fragments.
- Established tumor xenografts from reporter gene-transduced cells for in vivo imaging.
Main Results:
- Demonstrated quantification of EGFR activation and downstream signaling via optical imaging of reconstituted luciferase.
- Visualized changes in EGFR activation following radiotherapy and EGFR inhibitor treatment.
- Observed rapid radiation-induced EGFR activation and inhibitor-mediated signal suppression in xenograft models.
Conclusions:
- Proposed a new methodology for optical imaging and quantification of RTK activities in vivo.
- Highlighted the system's applicability for studying RTK biological regulation.
- Suggested its utility in developing and evaluating novel RTK-targeted therapeutics.
