title: Cerenkov luminescence tomography of aminopeptidase N (APN/CD13) expression in mice bearing HT1080 tumors.
abstract: In vivo imaging of aminopeptidase N (APN/CD13) expression is crucial for the early detection of cancer. This study attempted to show that APN/CD13 expression can be imaged and quantified with novel Cerenkov luminescence tomography (CLT). Na131I with various activities was placed at different depths in a tissue-mimicking phantom, and various porcine tissues and luminescent images were acquired. The binding of 131I-NGR with human fibrosarcoma HT1080 and human colon cancer HT-29 cells was detected with Cerenkov luminescence imaging (CLI). Nude mice bearing HT-1080 tumors were imaged after injection with 131I-NGR using both planar and tomographic CLI methods. The penetration depth increased with ascending activity of Na131I. There was a robust linear correlation between the optical signal intensity and the HT1080 cell numbers (r2 = .9691), as well as the activity (r2 = .9860). The three-dimensional visualization CLT results clearly showed that 131I-NGR uptake in tumor tissues represented a high expression of the APN/CD13 receptor. CLT also allowed quantifying 131I-NGR uptake in tumor tissues showing an average activity of 0.1388 ± 4.6788E-6 MBq in tumor tissues. Our study indicated that 131I-NGR combined with CLT allowed us to image and quantify tumor-associated APN/CD13 expression noninvasively. The promising CLT technique could be potentially used for sensitively evaluating tumor angiogenesis in vivo.
authors.affiliation: School of Life Sciences and Technology, Xidian University, Xi’an, China.
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Hu
authors.forename: Weidong
authors.initials: W
authors.lastname: Yang
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Ma
authors.forename: Wenhui
authors.initials: W
authors.lastname: Ma
authors.forename: Xiaochao
authors.initials: X
authors.lastname: Qu
authors.forename: Jimin
authors.initials: J
authors.lastname: Liang
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Jie
authors.initials: J
authors.lastname: Tian
mesh_terms: D000818:Animals; D018826:CD13 Antigens / Q000378:metabolism*; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000175:diagnosis / Q000378:metabolism; D005354:Fibrosarcoma / Q000175:diagnosis* / Q000378:metabolism; D019073:HT29 Cells; D006801:Humans; D007457:Iodine Radioisotopes; D008163:Luminescent Measurements / Q000379:methods*; D051379:Mice; D008819:Mice, Nude
chemical_list: D007457:Iodine Radioisotopes; D018826:CD13 Antigens