Fluorine-18 Labeling of the HER2-Targeting Single-Domain Antibody 2Rs15d Using a Residualizing Label and Preclinical Evaluation

Zhengyuan Zhou, Ganesan Vaidyanathan*, Darryl McDougald, Choong Mo Kang, Irina V Balyasnikova, Nick Devoogdt, Angeline N. Ta, Brian R. McNaughton, Michael R. Zalutsky

*Corresponding author for this work

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Purpose: Our previous studies with F-18-labeled anti-HER2 single-domain antibodies (sdAbs) utilized 5F7, which binds to the same epitope on HER2 as trastuzumab, complicating its use for positron emission tomography (PET) imaging of patients undergoing trastuzumab therapy. On the other hand, sdAb 2Rs15d binds to a different epitope on HER2 and thus might be a preferable vector for imaging in these patients. The aim of this study was to evaluate the tumor targeting of F-18 -labeled 2Rs15d in HER2-expressing breast carcinoma cells and xenografts. Procedures: sdAb 2Rs15d was labeled with the residualizing labels N-succinimidyl 3-((4-(4-[18F]fluorobutyl)-1H-1,2,3-triazol-1-yl)methyl)-5-(guanidinomethyl)benzoate ([18F]RL-I) and N-succinimidyl 4-guanidinomethyl-3-[125I]iodobenzoate ([125I]SGMIB), and the purity and HER2-specific binding affinity and immunoreactivity were assessed after labeling. The biodistribution of I-125- and F-18-labeled 2Rs15d was determined in SCID mice bearing subcutaneous BT474M1 xenografts. MicroPET/x-ray computed tomograph (CT) imaging of [18F]RL-I-2Rs15d was performed in this model and compared to that of nonspecific sdAb [18F]RL-I-R3B23. MicroPET/CT imaging was also done in an intracranial HER2-positive breast cancer brain metastasis model after administration of 2Rs15d-, 5F7-, and R3B23-[18F]RL-I conjugates. Results: [18F]RL-I was conjugated to 2Rs15d in 40.8 ± 9.1 % yield and with a radiochemical purity of 97–100 %. Its immunoreactive fraction (IRF) and affinity for HER2-specific binding were 79.2 ± 5.4 % and 7.1 ± 0.4 nM, respectively. [125I]SGMIB was conjugated to 2Rs15d in 58.4 ± 8.2 % yield and with a radiochemical purity of 95–99 %; its IRF and affinity for HER2-specific binding were 79.0 ± 12.9 % and 4.5 ± 0.8 nM, respectively. Internalized radioactivity in BT474M1 cells in vitro for [18F]RL-I-2Rs15d was 43.7 ± 3.6, 36.5 ± 2.6, and 21.7 ± 1.2 % of initially bound radioactivity at 1, 2, and 4 h, respectively, and was similar to that seen for [125I]SGMIB-2Rs15d. Uptake of [18F]RL-I-2Rs15d in subcutaneous xenografts was 16–20 %ID/g over 1–3 h. Subcutaneous tumor could be clearly delineated by microPET/CT imaging with [18F]RL-I-2Rs15d but not with [18F]RL-I-R3B23. Intracranial breast cancer brain metastases could be visualized after intravenous administration of both [18F]RL-I-2Rs15d and [18F]RL-I-5F7. Conclusions: Although radiolabeled 2Rs15d conjugates exhibited lower tumor cell retention both in vitro and in vivo than that observed previously for 5F7, given that it binds to a different epitope on HER2 from those targeted by the clinically utilized HER2-targeted therapeutic antibodies trastuzumab and pertuzumab, F-18-labeled 2Rs15d has potential for assessing HER2 status by PET imaging after trastuzumab and/or pertuzumab therapy.

Original languageEnglish (US)
Pages (from-to)867-877
Number of pages11
JournalMolecular Imaging and Biology
Volume19
Issue number6
DOIs
StatePublished - Dec 1 2017

Fingerprint

Single-Domain Antibodies
Fluorine
Heterografts
Epitopes
Breast Neoplasms
Brain Neoplasms
Positron-Emission Tomography
Radioactivity
Neoplasm Metastasis
Neoplasms
SCID Mice
Intravenous Administration
Therapeutics
X-Rays
N-succinimidyl 4-guanidinomethyl-3-iodobenzoate
Trastuzumab
Antibodies

Keywords

  • Breast cancer
  • Fluorine-18
  • HER2
  • PET
  • Single-domain antibody
  • Trastuzumab

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research

Cite this

Zhou, Zhengyuan ; Vaidyanathan, Ganesan ; McDougald, Darryl ; Kang, Choong Mo ; Balyasnikova, Irina V ; Devoogdt, Nick ; Ta, Angeline N. ; McNaughton, Brian R. ; Zalutsky, Michael R. / Fluorine-18 Labeling of the HER2-Targeting Single-Domain Antibody 2Rs15d Using a Residualizing Label and Preclinical Evaluation. In: Molecular Imaging and Biology. 2017 ; Vol. 19, No. 6. pp. 867-877.
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title = "Fluorine-18 Labeling of the HER2-Targeting Single-Domain Antibody 2Rs15d Using a Residualizing Label and Preclinical Evaluation",
abstract = "Purpose: Our previous studies with F-18-labeled anti-HER2 single-domain antibodies (sdAbs) utilized 5F7, which binds to the same epitope on HER2 as trastuzumab, complicating its use for positron emission tomography (PET) imaging of patients undergoing trastuzumab therapy. On the other hand, sdAb 2Rs15d binds to a different epitope on HER2 and thus might be a preferable vector for imaging in these patients. The aim of this study was to evaluate the tumor targeting of F-18 -labeled 2Rs15d in HER2-expressing breast carcinoma cells and xenografts. Procedures: sdAb 2Rs15d was labeled with the residualizing labels N-succinimidyl 3-((4-(4-[18F]fluorobutyl)-1H-1,2,3-triazol-1-yl)methyl)-5-(guanidinomethyl)benzoate ([18F]RL-I) and N-succinimidyl 4-guanidinomethyl-3-[125I]iodobenzoate ([125I]SGMIB), and the purity and HER2-specific binding affinity and immunoreactivity were assessed after labeling. The biodistribution of I-125- and F-18-labeled 2Rs15d was determined in SCID mice bearing subcutaneous BT474M1 xenografts. MicroPET/x-ray computed tomograph (CT) imaging of [18F]RL-I-2Rs15d was performed in this model and compared to that of nonspecific sdAb [18F]RL-I-R3B23. MicroPET/CT imaging was also done in an intracranial HER2-positive breast cancer brain metastasis model after administration of 2Rs15d-, 5F7-, and R3B23-[18F]RL-I conjugates. Results: [18F]RL-I was conjugated to 2Rs15d in 40.8 ± 9.1 {\%} yield and with a radiochemical purity of 97–100 {\%}. Its immunoreactive fraction (IRF) and affinity for HER2-specific binding were 79.2 ± 5.4 {\%} and 7.1 ± 0.4 nM, respectively. [125I]SGMIB was conjugated to 2Rs15d in 58.4 ± 8.2 {\%} yield and with a radiochemical purity of 95–99 {\%}; its IRF and affinity for HER2-specific binding were 79.0 ± 12.9 {\%} and 4.5 ± 0.8 nM, respectively. Internalized radioactivity in BT474M1 cells in vitro for [18F]RL-I-2Rs15d was 43.7 ± 3.6, 36.5 ± 2.6, and 21.7 ± 1.2 {\%} of initially bound radioactivity at 1, 2, and 4 h, respectively, and was similar to that seen for [125I]SGMIB-2Rs15d. Uptake of [18F]RL-I-2Rs15d in subcutaneous xenografts was 16–20 {\%}ID/g over 1–3 h. Subcutaneous tumor could be clearly delineated by microPET/CT imaging with [18F]RL-I-2Rs15d but not with [18F]RL-I-R3B23. Intracranial breast cancer brain metastases could be visualized after intravenous administration of both [18F]RL-I-2Rs15d and [18F]RL-I-5F7. Conclusions: Although radiolabeled 2Rs15d conjugates exhibited lower tumor cell retention both in vitro and in vivo than that observed previously for 5F7, given that it binds to a different epitope on HER2 from those targeted by the clinically utilized HER2-targeted therapeutic antibodies trastuzumab and pertuzumab, F-18-labeled 2Rs15d has potential for assessing HER2 status by PET imaging after trastuzumab and/or pertuzumab therapy.",
keywords = "Breast cancer, Fluorine-18, HER2, PET, Single-domain antibody, Trastuzumab",
author = "Zhengyuan Zhou and Ganesan Vaidyanathan and Darryl McDougald and Kang, {Choong Mo} and Balyasnikova, {Irina V} and Nick Devoogdt and Ta, {Angeline N.} and McNaughton, {Brian R.} and Zalutsky, {Michael R.}",
year = "2017",
month = "12",
day = "1",
doi = "10.1007/s11307-017-1082-x",
language = "English (US)",
volume = "19",
pages = "867--877",
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Fluorine-18 Labeling of the HER2-Targeting Single-Domain Antibody 2Rs15d Using a Residualizing Label and Preclinical Evaluation. / Zhou, Zhengyuan; Vaidyanathan, Ganesan; McDougald, Darryl; Kang, Choong Mo; Balyasnikova, Irina V; Devoogdt, Nick; Ta, Angeline N.; McNaughton, Brian R.; Zalutsky, Michael R.

In: Molecular Imaging and Biology, Vol. 19, No. 6, 01.12.2017, p. 867-877.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Fluorine-18 Labeling of the HER2-Targeting Single-Domain Antibody 2Rs15d Using a Residualizing Label and Preclinical Evaluation

AU - Zhou, Zhengyuan

AU - Vaidyanathan, Ganesan

AU - McDougald, Darryl

AU - Kang, Choong Mo

AU - Balyasnikova, Irina V

AU - Devoogdt, Nick

AU - Ta, Angeline N.

AU - McNaughton, Brian R.

AU - Zalutsky, Michael R.

PY - 2017/12/1

Y1 - 2017/12/1

N2 - Purpose: Our previous studies with F-18-labeled anti-HER2 single-domain antibodies (sdAbs) utilized 5F7, which binds to the same epitope on HER2 as trastuzumab, complicating its use for positron emission tomography (PET) imaging of patients undergoing trastuzumab therapy. On the other hand, sdAb 2Rs15d binds to a different epitope on HER2 and thus might be a preferable vector for imaging in these patients. The aim of this study was to evaluate the tumor targeting of F-18 -labeled 2Rs15d in HER2-expressing breast carcinoma cells and xenografts. Procedures: sdAb 2Rs15d was labeled with the residualizing labels N-succinimidyl 3-((4-(4-[18F]fluorobutyl)-1H-1,2,3-triazol-1-yl)methyl)-5-(guanidinomethyl)benzoate ([18F]RL-I) and N-succinimidyl 4-guanidinomethyl-3-[125I]iodobenzoate ([125I]SGMIB), and the purity and HER2-specific binding affinity and immunoreactivity were assessed after labeling. The biodistribution of I-125- and F-18-labeled 2Rs15d was determined in SCID mice bearing subcutaneous BT474M1 xenografts. MicroPET/x-ray computed tomograph (CT) imaging of [18F]RL-I-2Rs15d was performed in this model and compared to that of nonspecific sdAb [18F]RL-I-R3B23. MicroPET/CT imaging was also done in an intracranial HER2-positive breast cancer brain metastasis model after administration of 2Rs15d-, 5F7-, and R3B23-[18F]RL-I conjugates. Results: [18F]RL-I was conjugated to 2Rs15d in 40.8 ± 9.1 % yield and with a radiochemical purity of 97–100 %. Its immunoreactive fraction (IRF) and affinity for HER2-specific binding were 79.2 ± 5.4 % and 7.1 ± 0.4 nM, respectively. [125I]SGMIB was conjugated to 2Rs15d in 58.4 ± 8.2 % yield and with a radiochemical purity of 95–99 %; its IRF and affinity for HER2-specific binding were 79.0 ± 12.9 % and 4.5 ± 0.8 nM, respectively. Internalized radioactivity in BT474M1 cells in vitro for [18F]RL-I-2Rs15d was 43.7 ± 3.6, 36.5 ± 2.6, and 21.7 ± 1.2 % of initially bound radioactivity at 1, 2, and 4 h, respectively, and was similar to that seen for [125I]SGMIB-2Rs15d. Uptake of [18F]RL-I-2Rs15d in subcutaneous xenografts was 16–20 %ID/g over 1–3 h. Subcutaneous tumor could be clearly delineated by microPET/CT imaging with [18F]RL-I-2Rs15d but not with [18F]RL-I-R3B23. Intracranial breast cancer brain metastases could be visualized after intravenous administration of both [18F]RL-I-2Rs15d and [18F]RL-I-5F7. Conclusions: Although radiolabeled 2Rs15d conjugates exhibited lower tumor cell retention both in vitro and in vivo than that observed previously for 5F7, given that it binds to a different epitope on HER2 from those targeted by the clinically utilized HER2-targeted therapeutic antibodies trastuzumab and pertuzumab, F-18-labeled 2Rs15d has potential for assessing HER2 status by PET imaging after trastuzumab and/or pertuzumab therapy.

AB - Purpose: Our previous studies with F-18-labeled anti-HER2 single-domain antibodies (sdAbs) utilized 5F7, which binds to the same epitope on HER2 as trastuzumab, complicating its use for positron emission tomography (PET) imaging of patients undergoing trastuzumab therapy. On the other hand, sdAb 2Rs15d binds to a different epitope on HER2 and thus might be a preferable vector for imaging in these patients. The aim of this study was to evaluate the tumor targeting of F-18 -labeled 2Rs15d in HER2-expressing breast carcinoma cells and xenografts. Procedures: sdAb 2Rs15d was labeled with the residualizing labels N-succinimidyl 3-((4-(4-[18F]fluorobutyl)-1H-1,2,3-triazol-1-yl)methyl)-5-(guanidinomethyl)benzoate ([18F]RL-I) and N-succinimidyl 4-guanidinomethyl-3-[125I]iodobenzoate ([125I]SGMIB), and the purity and HER2-specific binding affinity and immunoreactivity were assessed after labeling. The biodistribution of I-125- and F-18-labeled 2Rs15d was determined in SCID mice bearing subcutaneous BT474M1 xenografts. MicroPET/x-ray computed tomograph (CT) imaging of [18F]RL-I-2Rs15d was performed in this model and compared to that of nonspecific sdAb [18F]RL-I-R3B23. MicroPET/CT imaging was also done in an intracranial HER2-positive breast cancer brain metastasis model after administration of 2Rs15d-, 5F7-, and R3B23-[18F]RL-I conjugates. Results: [18F]RL-I was conjugated to 2Rs15d in 40.8 ± 9.1 % yield and with a radiochemical purity of 97–100 %. Its immunoreactive fraction (IRF) and affinity for HER2-specific binding were 79.2 ± 5.4 % and 7.1 ± 0.4 nM, respectively. [125I]SGMIB was conjugated to 2Rs15d in 58.4 ± 8.2 % yield and with a radiochemical purity of 95–99 %; its IRF and affinity for HER2-specific binding were 79.0 ± 12.9 % and 4.5 ± 0.8 nM, respectively. Internalized radioactivity in BT474M1 cells in vitro for [18F]RL-I-2Rs15d was 43.7 ± 3.6, 36.5 ± 2.6, and 21.7 ± 1.2 % of initially bound radioactivity at 1, 2, and 4 h, respectively, and was similar to that seen for [125I]SGMIB-2Rs15d. Uptake of [18F]RL-I-2Rs15d in subcutaneous xenografts was 16–20 %ID/g over 1–3 h. Subcutaneous tumor could be clearly delineated by microPET/CT imaging with [18F]RL-I-2Rs15d but not with [18F]RL-I-R3B23. Intracranial breast cancer brain metastases could be visualized after intravenous administration of both [18F]RL-I-2Rs15d and [18F]RL-I-5F7. Conclusions: Although radiolabeled 2Rs15d conjugates exhibited lower tumor cell retention both in vitro and in vivo than that observed previously for 5F7, given that it binds to a different epitope on HER2 from those targeted by the clinically utilized HER2-targeted therapeutic antibodies trastuzumab and pertuzumab, F-18-labeled 2Rs15d has potential for assessing HER2 status by PET imaging after trastuzumab and/or pertuzumab therapy.

KW - Breast cancer

KW - Fluorine-18

KW - HER2

KW - PET

KW - Single-domain antibody

KW - Trastuzumab

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U2 - 10.1007/s11307-017-1082-x

DO - 10.1007/s11307-017-1082-x

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VL - 19

SP - 867

EP - 877

JO - Molecular Imaging and Biology

JF - Molecular Imaging and Biology

SN - 1536-1632

IS - 6

ER -