Evaluation of 99m Tc-MccJ25 peptide analog in mice bearing B16F10 melanoma tumor as a diagnostic radiotracer

Abstract

<strong><em>Objective(s): </em></strong>Despite recent advances in treatment modalities, cancer remains a major source of morbidity and mortality throughout the world. Currently, the development of sensitive and specific molecular imaging probes for early diagnosis of cancer is still a problematic challenge. Previous studies have been shown that some of the antimicrobial peptides (AMPs) exhibit a broad spectrum of cytotoxic activity against cancerous cells in addition to their antimicrobial activities. MicrocinJ25 (MccJ25) is an antimicrobial peptide that is produced by <em>Escherichia coli </em>(<em>E. coli</em>) strain. The aim of this study was to investigate the potential of a new peptide radiopharmaceutical derived from MccJ25 for diagnosis of melanoma tumor bearing C57BL/6 mice.<br /> <strong><em>Methods: </em></strong>A 14 amino acid analog of MccJ25 was labeled with technetium-99m (99mTc) through hydrazinonicotinamide (HYNIC) chelator and tricine as coligand. In vivo tumor uptake and tissue distribution were evaluated. The in vivo biodistribution studies were determined in C57BL/6 mice bearing B16F10 tumor.<br /> <strong><em>Results: </em></strong>The amount of non-peptide related 99mTc-impurities that measured by thin layer chromatography (TLC) did not exceed 5% of the total radioactivity. The in vitro binding to B16F10 cells was 30.73 ± 0.9% after 1 h incubation at 37°C, and saturation binding experiments showed good affinity for radio-complex (K_d=47.98±6.25 nM). The melanoma tumor was clearly visible up 1 h post-injection by gamma camera imaging.<br /> <strong><em>Conclusion: </em></strong>The results showed that 99mTc-labeld peptide could be a promising candidate as a targeting radiopharmaceutical for melanoma tumor imaging in mice.