title: ImmunoPET for assessing the differential uptake of a CD146-specific monoclonal antibody in lung cancer.
abstract: OBJECTIVE
  Overexpression of CD146 in solid tumors has been linked to disease progression, invasion, and metastasis. We describe the generation of a64Cu-labeled CD146-specific antibody and its use for quantitative immunoPET imaging of CD146 expression in six lung cancer models.
  
  
  METHODS
  The anti-CD146 antibody (YY146) was conjugated to 1,4,7-triazacyclononane-triacetic acid (NOTA) and radiolabeled with64Cu. CD146 expression was evaluated in six human lung cancer cell lines (A549, NCI-H358, NCI-H522, HCC4006, H23, and NCI-H460) by flow cytometry and quantitative western blot studies. The biodistribution and tumor uptake of64Cu-NOTA-YY146 was assessed by sequential PET imaging in athymic nude mice bearing subcutaneous lung cancer xenografts. The correlation between CD146 expression and tumor uptake of64Cu-NOTA-YY146 was evaluated by graphical software while ex vivo biodistribution and immunohistochemistry studies were performed to validate the accuracy of PET data and spatial expression of CD146.
  
  
  RESULTS
  Flow cytometry and western blot studies showed similar findings with H460 and H23 cells showing high levels of expression of CD146. Small differences in CD146 expression levels were found among A549, H4006, H522, and H358 cells. Tumor uptake of64Cu-NOTA-YY146 was highest in CD146-expressing H460 and H23 tumors, peaking at 20.1 ± 2.86 and 11.6 ± 2.34 %ID/g at 48 h after injection (n = 4). Tumor uptake was lowest in the H522 model (4.1 ± 0.98 %ID/g at 48 h after injection; n = 4), while H4006, A549 and H358 exhibited similar uptake of64Cu-NOTA-YY146. A positive correlation was found between tumor uptake of64Cu-NOTA-YY146 (%ID/g) and relative CD146 expression (r2= 0.98, p < 0.01). Ex vivo biodistribution confirmed the accuracy of the PET data.
  
  
  CONCLUSIONS
  The strong correlation between tumor uptake of64Cu-NOTA-YY146 and CD146 expression demonstrates the potential use of this radiotracer for imaging tumors that elicit varying levels of CD146. In the future, this tool may promote enhanced monitoring of therapeutic response and improved patient stratification.
authors.affiliation: Department of Radiology, University of Wisconsin - Madison, WI 53705, USA.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Sun
authors.affiliation: Department of Medical Physics, University of Wisconsin - Madison, WI 53705, USA.
authors.forename: Christopher G
authors.initials: CG
authors.lastname: England
authors.affiliation: Department of Medical Physics, University of Wisconsin - Madison, WI 53705, USA.
authors.forename: Reinier
authors.initials: R
authors.lastname: Hernandez
authors.affiliation: Department of Medical Physics, University of Wisconsin - Madison, WI 53705, USA.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Graves
authors.affiliation: Department of Biomedical Engineering, University of Wisconsin - Madison, WI 53705, USA.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Majewski
authors.affiliation: Department of Radiology, University of Wisconsin - Madison, WI 53705, USA.
authors.forename: Anyanee
authors.initials: A
authors.lastname: Kamkaew
authors.affiliation: Department of Radiology, University of Wisconsin - Madison, WI 53705, USA.
authors.forename: Dawei
authors.initials: D
authors.lastname: Jiang
authors.affiliation: Department of Medical Physics, University of Wisconsin - Madison, WI 53705, USA.
authors.forename: Todd E
authors.initials: TE
authors.lastname: Barnhart
authors.affiliation: Department of Radiology, University of Wisconsin - Madison, WI 53705, USA.
authors.forename: Yunan
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Radiology, University of Wisconsin - Madison, WI 53705, USA.|Department of Medical Physics, University of Wisconsin - Madison, WI 53705, USA.|Department of Biomedical Engineering, University of Wisconsin - Madison, WI 53705, USA.|University of Wisconsin Carbone Cancer Center, Madison, WI 53705, USA.
authors.forename: Weibo
authors.initials: W
authors.lastname: Cai
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D051929:CD146 Antigen / Q000276:immunology; D045744:Cell Line, Tumor; D056831:Coordination Complexes / Q000276:immunology*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000276:immunology*; D051379:Mice; D008819:Mice, Nude; D057054:Molecular Imaging / Q000379:methods; D010455:Peptides / Q000276:immunology*; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000276:immunology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: C000600262:64Cu-NOTA-3-4A; D000911:Antibodies, Monoclonal; D051929:CD146 Antigen; D056831:Coordination Complexes; C497902:MCAM protein, human; D010455:Peptides; D019275:Radiopharmaceuticals
keywords: CD146; Lung cancer; Molecular imaging; Monoclonal antibody; Positron emission tomography (PET); YY146