Radio-labeling of T7 Peptide with 99mTc and Its Biodistribution 
in Nude Mice Bearing Non-small Cell Lung Cancer

Abstract

Background and objective Lung cancer is a malignant tumor with high mortality rates. This study aims to develop potential candidates of integrin αvβ3 imaging agents, which can facilitate the diagnosis and treatment of lung cancer. Methods The T7 peptide was labeled with carbonyl technetium. The thin layer chromatography with acetone as the development system was performed to investigate the purity and stability of 99mTc-T7. The binding affinity of 99mTc-T7 with NCI-H157 tumor cells was determined. The biodistribution of 99mTc-T7 in nude mice bearing non-small cell lung carcinoma was observed after injection of 99mTc-T7 at 0.5 h, 1 h, 2 h, 4 h, and 8 h, and the radioactive ratio of tumor (T) and non-tumor tissues (NT) was calculated. Results 99mTc labeled T7 had high radiochemical purity of more than 90%, which does not require further purification, with good stability in vitro. The association and dissociation constant (KD) of 99mTc-T7 with NCI-H157 tumor cells was 196.1 nM. 99mTc-T7 was mainly metabolism through the internal organs with rapid blood removal. Moreover, the uptake in tumor tissue was significantly higher than the muscle with tumor/muscle ratio of 5.8. In addition, the 99mTc-T7 exhibited a transient accumulation in the lungs. Conclusion The 99mTc-T7 could be prepared using a simple method, had high labeling rate and good stability, and could be accumulated at tumor site. Thus, 99mTc-T7 is a potential lung cancer SPECT/CT imaging agent.

Keywords

• 99mTc-T7
• Tumstatin T7 peptide
• Integrin αvβ3
• Lung cancer imaging
• Biodistribution