Evaluation of 68Ga-labeled MG7 antibody: a targeted probe for PET/CT imaging of gastric cancer.
MG7-Ag, a specific gastric cancer-associated antigen, can be used to non-invasively monitor gastric cancer by molecular imaging with positron emission tomography/computed tomography (PET/CT). In this study, we prepared and evaluated a (68)Ga-labeled MG7 antibody as a molecular probe for nanoPET/CT imaging of gastric cancer in a BGC-823 tumor xenografted mouse model. Macrocyclic chelator 1,4,7-triazacyclononane-N,N0,N00-triacetic acid (NOTA)-conjugated MG7 antibody was synthesized and radiolabeled with (68)Ga (t1/2 = 67.71 min). Then, (68)Ga-NOTA-MG7 was tested using in vitro cytological studies, in vivo nanoPET/CT and Cerenkov imaging studies as well as ex vivo biodistribution and histology studies. The in vitro experiments demonstrated that (68)Ga-NOTA-MG7 has an excellent radiolabeling efficiency of approximately 99% without purification, and it is stable in serum after 120 min of incubation. Cell uptake and retention studies confirmed that (68)Ga-NOTA-MG7 has good binding affinity and tumor cell retention. For the nanoPET imaging study, the predominant uptake of (68)Ga-NOTA-MG7 was visualized in tumor, liver and kidneys. The tumor uptake reached at its peak (2.53 ± 0.28%ID/g) at 60 min pi. Cherenkov imaging also confirmed the specificity of tumor uptake. Moreover, the biodistribution results were consistent with the quantification data of nanoPET/CT imaging. Histologic analysis also demonstrated specific staining of BGC-823 tumor cell lines.
State Key Laboratory of Cancer Biology &Institute of Digestive Diseases, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
Bing
B
Xu
State Key Laboratory of Cancer Biology &Institute of Digestive Diseases, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
Xiaowei
X
Li
State Key Laboratory of Cancer Biology &Institute of Digestive Diseases, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
Jipeng
J
Yin
State Key Laboratory of Cancer Biology &Institute of Digestive Diseases, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
Cong
C
Liang
State Key Laboratory of Cancer Biology &Institute of Digestive Diseases, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
Lijuan
L
Liu
State Key Laboratory of Cancer Biology &Institute of Digestive Diseases, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
Zhaoyan
Z
Qiu
State Key Laboratory of Cancer Biology &Institute of Digestive Diseases, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
Liping
L
Yao
State Key Laboratory of Cancer Biology &Institute of Digestive Diseases, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
Yongzhan
Y
Nie
Department of Nuclear Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
Jing
J
Wang
State Key Laboratory of Cancer Biology &Institute of Digestive Diseases, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
Kaichun
K
Wu
D000818:Animals; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000276:immunology*; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D005260:Female; D005710:Gallium Radioisotopes; D064593:Heterografts; D006801:Humans; D051379:Mice; D018613:Microscopy, Confocal; D049268:Positron-Emission Tomography; D013274:Stomach Neoplasms / Q000175:diagnosis* / Q000276:immunology*; D014018:Tissue Distribution; D014057:Tomography, X-Ray Computed
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D005710:Gallium Radioisotopes