Automated Synthesis Of N-succinimidyl 4-"18~F"fluorobenzoate And 18 F-label C2A Domain Of Synaptotagmin I As A Probe For The Detection Of Apoptosis

Objective :1.To develop and optimization a module assisted to automated production of N-succinimidyl 4-[¹⁸F]fluorobenzoate ([¹⁸F]-SFB) that is used for further ¹⁸F labeling C2A Domain of Synaptotagmin I.2. To evaluated it bio-distribution and applied for detecting the tumor apoptosis in rabbit model after chemotherapy. apoptosis of rabbits after chemotherapy. Methods: 1. GE TRACERlab FX FDG and TRACERlab FX FN module which used for regular synthesis of ¹⁸F-FDG were modified and programming to fully produce of ¹⁸F-SFB. High-performance liquid chromatography (HPLC) was used to analyze the products. C2A- glutathione S-transferase (GST) subsequently conjugated with ¹⁸F-SFB and purified by BIO-GEL P6 filtration, and Calculate the yield and specific activity.2. Jurkat cells were induced to apoptosis and assays it vitro binding. Pharmacokineti -cs and biodistribution were studied in healthy rats. Eight rabbits grafted with VX2 lung cancer were first treated by chemotherapy and then, 37MBq of ¹⁸F-FB-C2A- GST was administered via the auricular vein. Serial PET/CT imaging were performed at , VX2 lung cancer rabbits treated by paclitaxel,37MBq(1mCi) ¹⁸F-FB-C2A-GST was administered in rabbits via auricular vein , PET-CT imaging was performed before and post Paclitaxel chemotherapy, calculated the standard uptake value(SUV) of tumor and other imported organs. Rabbits were sacrificed after imaging and determination the apoptosis with pathology and immunohistochemistry in situ end labeling (TUNEL) and flow cytomety. Results: 1. The TRACERlab FXFDG and TRACERlab FXFN synthesizer module was successfully adapted to allow the synthesis of ¹⁸F-SFB. Including the separation of ¹⁸F-SFB using HPLC, the total times of all procedure were 87 min, the synthesis of ¹⁸F-FBA take 48min, the correction yield were 76.41%±4.0%(n=10), and the correction yield of ¹⁸F-SFB were 45.43%, the Radio chemical purity (RCP) were more than 95%. ¹⁸F-SFB can easy labeled to C2A-GST and the labeling ratio about 85%, and the RCP is nearly 99% after purification.2.Bio-distribution of mice shows ¹⁸F-FB-C2A-GST mainly excretion from kidneys, uptake peaks at about 30min, have a good blood clearance, the % ID / g of blood at 4h is1/6 of 15min after injection, no obvious uptake was found in heart,lungs,liver and other main organs. From PET-CT imagings, significant uptake was found in the tumor after chemotherapy , showed that ¹⁸F-FB-C2A-GST mainly excretion from kidneys, fast blood and kidney clearance was observed , no obvious uptake was found in heart,lungs,liver and other main organs .8 /20 rabbit were succeed grafted with VX2 of lung cancer, Then chemotherapy by paclitaxel , Before and after the apoptotic index of tumor apoptosis, Caspase-3 and SUV values were significantly different.Conclusion:¹⁸F-SFB can be automatically synthesized using the GE TRACERlabFXFDG and TRACERlabFXF-N module which regular yield of ¹⁸F-FDG.¹⁸F-SFB was easy conjugated with C2A Domain of Synaptotagmin I. ¹⁸F-FB-C2A-GST might be a potential molecular probe of PET-CT for detect of apoptosis with better bio-distribution and effectively after chemotherapy.