Use of fluorescent labeled anti–epidermal growth factor receptor antibody to image head and neck squamous cell carcinoma xenografts

Abstract

Physicians and surgeons rely on subtle tissue changes to detect the extent of tumors and the presence of residual disease in the clinical setting. The development of a cancer-specific fluorescent contrast agent has the potential to provide real-time tumor imaging in the clinic or operating room. Because epidermal growth factor receptor (EGFR) is highly overexpressed on the surface of head and neck squamous cell carcinoma (HNSCC), we sought to determine if fluorescently labeled anti-EGFR antibody could be used to image HNSCC xenografts in vivo. Cetuximab or control isotype-matched IgG1 was conjugated with the Cy5.5 fluorochrome and systemically injected into mice bearing human split thickness skin grafts, tumor cell line xenografts, transplanted human tumor xenografts, or mouse mesothelioma tumors. Xenografts were imaged by time-domain fluorescence imaging or fluorescence stereomicroscopy. Both imaging modalities detected specific uptake of cetuximab-Cy5.5 in HNSCC xenografts with significantly higher fluorescence levels relative to control IgG1-Cy5.5. Tumor xenograft fluorescence was higher compared with background (before injection), human split thickness skin grafts, or mouse mesothelioma tumors at 24, 48, and 72 h. Fluorescence was detected in multiple HNSCC tumor cell lines with variable EGFR expression levels. Mock resections of flank tumors using fluorescence stereomicroscopy showed that small (2 mm) specimens could be detected in the surgical wound bed. These results show the feasibility of using fluorescently labeled anti-EGFR antibody to detect human tumors in the surgical setting. [Mol Cancer Ther 2007;6(4):1230 -8]

Intraoperative Near-Infrared Fluorescence Tumor Imaging with Vascular Endothelial Growth Factor and Human Epidermal Growth Factor Receptor 2 Targeting Antibodies

“…This information adds to the recent data obtained for fluorescence-labeled antibodies targeting the epidermal growth factor receptor (EGFR), HER2, and the insulin-like growth factor receptor 1 (IGF-1R) (23)(24)(25)(26). Cetuximab labeled with the NIR fluorescent dye Cy5.5 showed specific tumor uptake in head and neck squamous cell carcinoma xenografts (23), whereas the IGF-1R targeting antibody AVE-1642 labeled with the NIR fluorescent dye Alexa 680 was specifically taken up by the R-/IGF-1R xenograft tumor (24).…”

Fluorescent labeled anti‐EGFR antibody for identification of regional and distant metastasis in a preclinical xenograft model

“…Although not addressed in the current study, we have previously shown that fluorescently labeled cetuximab is specific for primary tumors and demonstrates significantly higher fluorescence compared with human epithelial background (xenografted human skin grafts). 8 These results suggest that this technology could be used to facilitate transoral laser or robotic cases for primary tumors.…”

“…However, previous studies using the technique on human skin grafts did not demonstrate any detectable fluorescence. 8 Because this was a pilot study to demonstrate the feasibility of the imaging technique for detection of metastasis, a relatively small number of mice were used.…”

“…[8][9][10] The purpose of this study is to determine if the fluorescently labeled cetuximab could be used in head and neck cancer to detect metastatic disease. To address feasibility of this hypothesis, we assessed fluorescence imaging of metastatic head and neck cancer in the lung and neck in a preclinical murine model.…”

Imaging in animal models

“…Resection of the tumours was carried out under guidance of near-infrared fluorescence imaging, enabling identification of any remaining cancerous cells in situ [30]. In addition, further studies have utilised optical imaging to detect cervical node metastases in orthotopic mouse models as all nodes that showed a fluorescent signal were found to be malignant metastases from squamous cell carcinoma [31,32]. Thus, near-infrared fluorescence imaging can be used to delineate tumour margins and any malignant cells remaining post resection, making it an invaluable tool for animal model imaging.…”