TY - JOUR
T1 - Comparative biodistribution of imaging agents for in vivo molecular profiling of disseminated prostate cancer in mice bearing prostate cancer xenografts
T2 - Focus on 111In- and 125I-labeled anti-HER2 humanized monoclonal trastuzumab and ABY-025 Affibody
AU - Malmberg, Jennie
AU - Sandström, Mattias
AU - Wester, Kenneth
AU - Tolmachev, Vladimir
AU - Orlova, Anna
N1 - Funding Information:
This study was supported by the Swedish Cancer Society (Cancerfonden) and Swedish Research Council (Vetenskapsrådet) . The authors thank Affibody (Stockholm) for providing ABY-025 and Apoteket Farmaci (Cytostatikaberedniongen, Sjukhusapoteket Uppsala) for assistance in obtaining of Herceptin.
Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2011/11
Y1 - 2011/11
N2 - Introduction: Human epidermal growth factor receptor type 2 (HER2) overexpression supports proliferation of androgen-independent prostate cancer (PC). Radionuclide molecular imaging of HER2 expression in disseminated PC would aid in the selection of patients who are likely responders to HER2 targeting therapy. In this study, we evaluated whether ABY-025 Affibody molecule, a small (~ 7-kDa) HER2-binding scaffold protein, produces superior tumor-to-nontumor ratios compared with those obtained through the use of radiolabeled humanized anti-HER2 antibody, trastuzumab. The influence of 111In vs. 125I radiolabel was evaluated for both tracers. Methods: ABY-025 was labeled with 111In using 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid chelator, site-specifically coupled to the C-terminus via the maleimido derivative. Trastuzumab was labeled with 111In using a CHX-A diethylene triamine pentaacetic acid (DTPA) chelator. An indirect radioiodination with [ 125I]-N-succinimidyl-para-iodobenzoate was used for both targeting proteins. Biodistribution of all labeled targeting proteins was evaluated in mice bearing DU-145 PC xenografts. Results: The use of residualizing 111In-label facilitated better tumor uptake and better tumor-to-nontumor ratios for both targeting agents. [ 111In]-ABY-025 provided tumor uptake of 7.1±0.8% injected dose per gram of tissue (% ID/g) and tumor-to-blood ratio of 47±13 already at 6 h postinjection. The maximum tumor-to-nontumor ratios with [ 111In]-CHX-DTPA-trastuzumab were achieved at 72 h postinjection, whereas tumor uptake was 11±4% ID/g and tumor-to-blood ratio was 18±7. The biodistribution data were confirmed with gamma-camera imaging. Conclusions: Radiolabeled ABY-025 Affibody molecule provides higher contrast in imaging of HER2-expressing PC xenografts than radiolabeled trastuzumab. Residualizing radiometal label for ABY-025 provides better contrast in imaging of HER2-expressing PC xenografts than nonresidualizing radiohalogen.
AB - Introduction: Human epidermal growth factor receptor type 2 (HER2) overexpression supports proliferation of androgen-independent prostate cancer (PC). Radionuclide molecular imaging of HER2 expression in disseminated PC would aid in the selection of patients who are likely responders to HER2 targeting therapy. In this study, we evaluated whether ABY-025 Affibody molecule, a small (~ 7-kDa) HER2-binding scaffold protein, produces superior tumor-to-nontumor ratios compared with those obtained through the use of radiolabeled humanized anti-HER2 antibody, trastuzumab. The influence of 111In vs. 125I radiolabel was evaluated for both tracers. Methods: ABY-025 was labeled with 111In using 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid chelator, site-specifically coupled to the C-terminus via the maleimido derivative. Trastuzumab was labeled with 111In using a CHX-A diethylene triamine pentaacetic acid (DTPA) chelator. An indirect radioiodination with [ 125I]-N-succinimidyl-para-iodobenzoate was used for both targeting proteins. Biodistribution of all labeled targeting proteins was evaluated in mice bearing DU-145 PC xenografts. Results: The use of residualizing 111In-label facilitated better tumor uptake and better tumor-to-nontumor ratios for both targeting agents. [ 111In]-ABY-025 provided tumor uptake of 7.1±0.8% injected dose per gram of tissue (% ID/g) and tumor-to-blood ratio of 47±13 already at 6 h postinjection. The maximum tumor-to-nontumor ratios with [ 111In]-CHX-DTPA-trastuzumab were achieved at 72 h postinjection, whereas tumor uptake was 11±4% ID/g and tumor-to-blood ratio was 18±7. The biodistribution data were confirmed with gamma-camera imaging. Conclusions: Radiolabeled ABY-025 Affibody molecule provides higher contrast in imaging of HER2-expressing PC xenografts than radiolabeled trastuzumab. Residualizing radiometal label for ABY-025 provides better contrast in imaging of HER2-expressing PC xenografts than nonresidualizing radiohalogen.
KW - Affibody molecule
KW - Biodistribution
KW - HER2
KW - Prostate cancer
KW - Radiolabeling
KW - Trastuzumab
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U2 - 10.1016/j.nucmedbio.2011.04.005
DO - 10.1016/j.nucmedbio.2011.04.005
M3 - Article
C2 - 22137850
AN - SCOPUS:82655172565
VL - 38
SP - 1093
EP - 1102
JO - Nuclear Medicine and Biology
JF - Nuclear Medicine and Biology
SN - 0969-8051
IS - 8
ER -