Synthesis and evaluation of a 68Ga-labeled spermine derivative for tumor PET imaging

Background: The polyamine transporter system (PTS), which renders it a promising target for tumor therapy and imaging applications, facilitates the transmembrane transport of polyamines. We reported a novel derivative of spermine labeled with gallium-68 ([Ga-68]Ga-NOTA-Spermine) for the imaging of the PTS in mouse models of tumor. Results: The radiochemical yield of [Ga-68]Ga-NOTA-Spermine was determined to be 64-69 %, demonstrating exceptional stability and radiochemical purity (>98 %). Cellular uptake experiments revealed that A549 cells exhibited peak uptake of [Ga-68]Ga-NOTA-Spermine at 90 min (15.4 % +/- 0.68 %). Biodistribution analysis demonstrated significant accumulation of [Ga-68]Ga-NOTA-Spermine in kidneys and liver, while exhibiting low uptake levels in muscle, brain, and bones. Furthermore, Micro-PET/CT scans conducted on A549 tumor-bearing mouse models indicated substantial uptake of [Ga-68]Ga-NOTA-Spermine, with maximum tumor/muscle (T/M) ratios reaching 3.71. Conclusion: These results suggest that [Ga-68]Ga-NOTA-Spermine holds potential as a PET imaging agent for tumors with high levels of PTS.