Synthesis and biodistribution of 99Tcm-Cetuximab antibody for lung tumor targeted molecular imaging / 中华核医学与分子影像杂志

ABSTRACT

Objective To prepare and evaluate 99Tcm radiolabeled Cetuximab (C225) for imaging of EGFR specific binding.Methods Cetuximab antibody was reduced by 2-iminothiophene (2-IT).The radiolabeling of IT-Cetuximab with 99Tcm(99Tcm-IT-Cetuximab) was analyzed by HPLC,and was tested for in vitro stability and molecular integrity.The human lung cancer line (A549)-bearing nude mouse model was prepared for biodistribution and tumor targeted study.Tumor uptake was also measured by in vivo γ imaging.Results The labeling efficiency was 93.15％.The radiochemical purity was 96.46％ after purification.The in vitro stability was good in 5％ HSA,in which the radiochemical purity maintained above 80％ at 4 ℃ for 24 h.99Tcm-IT-Cetuximab showed good specific binding to tumor with peak uptake of (3.417±0.769) ％ID/g after 4 h.The T/NT ratio of blood increased to 1.454±0.174 at 24 h.γ imaging of A549-bearing nude mice xenografts also showed high T/NT ratio.Conclusions 99Tcm-IT-Cetuximab molecular probe could be prepared with high radiolabeling yield and radiochemical purity.It has excellent in vitro and in vivo stability,and shows specific uptake in A549 tumor.