Abstract
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Objectives Cetuximab, a chimeric (mouse/human) monoclonal antibody, is an epidermal growth factor receptor (EGFR) inhibitor used for the treatment of metastatic colorectal cancer, metastatic non-small cell lung cancer and head and neck cancer. In this study, we developed the HT-29-luc2 human colorectal xenograft models and using Re-188 labeled with cetuximab for cancer diagnostic imaging.
Methods Nude mice were inoculated with 1×106 HT29-luc2 cells by subcutaneous injection. Tumor was measured weekly by a digital caliper to document tumor growth. Nano-SPECT/CT imaging was performed in HT-29-luc2 tumor bearing mice model at 24 and 48h after injection of 188Re-cetuximab.
Results HT-29-luc2 tumor volume doubling time was 7.5days. The correlation (r2) between mean tumor volumn and bioluminescent imaging was 0.99. For nano-SPECT/CT imaging study, the highest SUV in tumor was 14.49 at 48 h after injection of 188Re-cetuximab. The Tumor/Muscle ratio at 24 and 48 h after administration was 2.39 and 6.25, respectively. The Tumor/Liver ratio at 24 and 48 h after administration was 0.75 and 1.44, respectively. Nano-SPECT/CT imaging showed that 188Re-cetuximab could target the tumor region.
Conclusions The nano-SPECT/CT imaging study results suggested potential benefit and advantage of 188Re-cetuximab was suitable as a diagnostic tracer for the imaging of colorectal cancer.