In vivo evaluation and small-animal PET/CT of a prostate cancer mouse model using 64Cu bombesin analogs

Side-by-side comparison of the CB-TE2A and DOTA chelation systems

Jered C Garrison, Tammy L. Rold, Gary L. Sieckman, Said Daibes Figueroa, Wynn A. Volkert, Silvia S. Jurisson, Timothy J. Hoffman

Research output: Contribution to journalArticle

123 Citations (Scopus)

Abstract

The BB2 receptor subtype, of the bombesin family of receptors, has been shown to be highly overexpressed in a variety of human tumors, including prostate cancer. Bombesin (BBN), a 14-amino acid peptide, has been shown to target the BB2 receptor with high affinity. 64Cu (half-life = 12.7 h, β+: 18%, Eβ+max = 653 keV; β-: 37%, Eβ-max = 578 keV) is a radioisotope that has clinical potential for application in both diagnostic imaging and radionuclide therapy. Recently, new chelation systems such as 1,4,8,11-tetraazabicyclo[6.6.2] hexadecane-4,11-diacetic acid (CB-TE2A) have been reported to significantly stabilize the 64Cu radiometal in vivo. The increased stability of the 64Cu-CB-TE2A chelate complex has been shown to significantly reduce nontarget retention compared with tetraazamacrocycles such as 1,4,7,10-tetraazacyclodoadecane-N,N′,N″,N‴-tetraacetic acid (DOTA). The aim of this study was to determine whether the CB-TE2A chelation system could significantly improve the in vivo stability of 64Cu bombesin analogs. The study directly compares 64Cu bombesin analogs using the CB-TE2A and DOTA chelation systems in a prostate cancer xenograft SCID (severely compromised immunodeficient) mouse model. Methods: The CB-TE2A-8-AOC-BBN(7-14)NH2 and DOTA-8-AOC-BBN(7-14) NH2 conjugates were synthesized and radiolabeled with 64Cu. The receptor-binding affinity and internalization profile of each metallated conjugate was evaluated using PC-3 cells. Pharmacokinetic and small-animal PET/CT studies were performed using female SCID mice bearing PC-3 xenografts. Results: In vivo BB2 receptor targeting was confirmed by tumor uptake values of 6.95 ± 2.27 and 4.95 ± 0.91 %ID/g (percentage injected dose per gram) at the 15-min time point for the 64Cu-CB-TE2A and 64Cu-DOTA radioconjugates, respectively. At the 24-h time point, liver uptake was substantially reduced for the 64Cu-CB-TE2A radioconjugate (0.21 ± 0.06 %ID/g) compared with the 64Cu-DOTA radioconjugate (7.80 ± 1.51 %ID/g). The 64Cu-CB-TE2A-8-AOC- BBN(7-14)NH2 radioconjugate demonstrated significant clearance, 98.60 ± 0.28 %ID, from the mouse at 24 h after injection. In contrast, only 67.84 ± 5.43 %ID of the 64Cu activity was excreted using the 64Cu-DOTA-8-AOC-BBN(7-14)NH2 radioconjugate because of nontarget retention. Conclusion: The pharmacokinetic and small-animal PET/CT studies demonstrate significantly improved nontarget tissue clearance for the 64Cu-CB-TE2A8-AOC-BBN(7-14)NH2. This is attributed to the improved in vivo stability of the 64Cu-CB-TE2A chelate complex as compared with the 64Cu-DOTA chelate complex.

Original languageEnglish (US)
Pages (from-to)1327-1337
Number of pages11
JournalJournal of Nuclear Medicine
Volume48
Issue number8
DOIs
StatePublished - Aug 1 2007

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Bombesin
Prostatic Neoplasms
Heterografts
Radioisotopes
Pharmacokinetics
Bombesin Receptors
Diagnostic Imaging
Half-Life
Neoplasms
(4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo(6.6.2)hexadecane)copper(II)
bombesin (7-14)
Amino Acids
Peptides
Injections
Acids
Liver

Keywords

  • BB2 receptor
  • Bombesin
  • Cu
  • Preclinical
  • Prostate cancer

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

Cite this

In vivo evaluation and small-animal PET/CT of a prostate cancer mouse model using 64Cu bombesin analogs : Side-by-side comparison of the CB-TE2A and DOTA chelation systems. / Garrison, Jered C; Rold, Tammy L.; Sieckman, Gary L.; Figueroa, Said Daibes; Volkert, Wynn A.; Jurisson, Silvia S.; Hoffman, Timothy J.

In: Journal of Nuclear Medicine, Vol. 48, No. 8, 01.08.2007, p. 1327-1337.

Research output: Contribution to journalArticle

Garrison, Jered C ; Rold, Tammy L. ; Sieckman, Gary L. ; Figueroa, Said Daibes ; Volkert, Wynn A. ; Jurisson, Silvia S. ; Hoffman, Timothy J. / In vivo evaluation and small-animal PET/CT of a prostate cancer mouse model using 64Cu bombesin analogs : Side-by-side comparison of the CB-TE2A and DOTA chelation systems. In: Journal of Nuclear Medicine. 2007 ; Vol. 48, No. 8. pp. 1327-1337.
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title = "In vivo evaluation and small-animal PET/CT of a prostate cancer mouse model using 64Cu bombesin analogs: Side-by-side comparison of the CB-TE2A and DOTA chelation systems",
abstract = "The BB2 receptor subtype, of the bombesin family of receptors, has been shown to be highly overexpressed in a variety of human tumors, including prostate cancer. Bombesin (BBN), a 14-amino acid peptide, has been shown to target the BB2 receptor with high affinity. 64Cu (half-life = 12.7 h, β+: 18{\%}, Eβ+max = 653 keV; β-: 37{\%}, Eβ-max = 578 keV) is a radioisotope that has clinical potential for application in both diagnostic imaging and radionuclide therapy. Recently, new chelation systems such as 1,4,8,11-tetraazabicyclo[6.6.2] hexadecane-4,11-diacetic acid (CB-TE2A) have been reported to significantly stabilize the 64Cu radiometal in vivo. The increased stability of the 64Cu-CB-TE2A chelate complex has been shown to significantly reduce nontarget retention compared with tetraazamacrocycles such as 1,4,7,10-tetraazacyclodoadecane-N,N′,N″,N‴-tetraacetic acid (DOTA). The aim of this study was to determine whether the CB-TE2A chelation system could significantly improve the in vivo stability of 64Cu bombesin analogs. The study directly compares 64Cu bombesin analogs using the CB-TE2A and DOTA chelation systems in a prostate cancer xenograft SCID (severely compromised immunodeficient) mouse model. Methods: The CB-TE2A-8-AOC-BBN(7-14)NH2 and DOTA-8-AOC-BBN(7-14) NH2 conjugates were synthesized and radiolabeled with 64Cu. The receptor-binding affinity and internalization profile of each metallated conjugate was evaluated using PC-3 cells. Pharmacokinetic and small-animal PET/CT studies were performed using female SCID mice bearing PC-3 xenografts. Results: In vivo BB2 receptor targeting was confirmed by tumor uptake values of 6.95 ± 2.27 and 4.95 ± 0.91 {\%}ID/g (percentage injected dose per gram) at the 15-min time point for the 64Cu-CB-TE2A and 64Cu-DOTA radioconjugates, respectively. At the 24-h time point, liver uptake was substantially reduced for the 64Cu-CB-TE2A radioconjugate (0.21 ± 0.06 {\%}ID/g) compared with the 64Cu-DOTA radioconjugate (7.80 ± 1.51 {\%}ID/g). The 64Cu-CB-TE2A-8-AOC- BBN(7-14)NH2 radioconjugate demonstrated significant clearance, 98.60 ± 0.28 {\%}ID, from the mouse at 24 h after injection. In contrast, only 67.84 ± 5.43 {\%}ID of the 64Cu activity was excreted using the 64Cu-DOTA-8-AOC-BBN(7-14)NH2 radioconjugate because of nontarget retention. Conclusion: The pharmacokinetic and small-animal PET/CT studies demonstrate significantly improved nontarget tissue clearance for the 64Cu-CB-TE2A8-AOC-BBN(7-14)NH2. This is attributed to the improved in vivo stability of the 64Cu-CB-TE2A chelate complex as compared with the 64Cu-DOTA chelate complex.",
keywords = "BB2 receptor, Bombesin, Cu, Preclinical, Prostate cancer",
author = "Garrison, {Jered C} and Rold, {Tammy L.} and Sieckman, {Gary L.} and Figueroa, {Said Daibes} and Volkert, {Wynn A.} and Jurisson, {Silvia S.} and Hoffman, {Timothy J.}",
year = "2007",
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language = "English (US)",
volume = "48",
pages = "1327--1337",
journal = "Journal of Nuclear Medicine",
issn = "0161-5505",
publisher = "Society of Nuclear Medicine Inc.",
number = "8",

}

TY - JOUR

T1 - In vivo evaluation and small-animal PET/CT of a prostate cancer mouse model using 64Cu bombesin analogs

T2 - Side-by-side comparison of the CB-TE2A and DOTA chelation systems

AU - Garrison, Jered C

AU - Rold, Tammy L.

AU - Sieckman, Gary L.

AU - Figueroa, Said Daibes

AU - Volkert, Wynn A.

AU - Jurisson, Silvia S.

AU - Hoffman, Timothy J.

PY - 2007/8/1

Y1 - 2007/8/1

N2 - The BB2 receptor subtype, of the bombesin family of receptors, has been shown to be highly overexpressed in a variety of human tumors, including prostate cancer. Bombesin (BBN), a 14-amino acid peptide, has been shown to target the BB2 receptor with high affinity. 64Cu (half-life = 12.7 h, β+: 18%, Eβ+max = 653 keV; β-: 37%, Eβ-max = 578 keV) is a radioisotope that has clinical potential for application in both diagnostic imaging and radionuclide therapy. Recently, new chelation systems such as 1,4,8,11-tetraazabicyclo[6.6.2] hexadecane-4,11-diacetic acid (CB-TE2A) have been reported to significantly stabilize the 64Cu radiometal in vivo. The increased stability of the 64Cu-CB-TE2A chelate complex has been shown to significantly reduce nontarget retention compared with tetraazamacrocycles such as 1,4,7,10-tetraazacyclodoadecane-N,N′,N″,N‴-tetraacetic acid (DOTA). The aim of this study was to determine whether the CB-TE2A chelation system could significantly improve the in vivo stability of 64Cu bombesin analogs. The study directly compares 64Cu bombesin analogs using the CB-TE2A and DOTA chelation systems in a prostate cancer xenograft SCID (severely compromised immunodeficient) mouse model. Methods: The CB-TE2A-8-AOC-BBN(7-14)NH2 and DOTA-8-AOC-BBN(7-14) NH2 conjugates were synthesized and radiolabeled with 64Cu. The receptor-binding affinity and internalization profile of each metallated conjugate was evaluated using PC-3 cells. Pharmacokinetic and small-animal PET/CT studies were performed using female SCID mice bearing PC-3 xenografts. Results: In vivo BB2 receptor targeting was confirmed by tumor uptake values of 6.95 ± 2.27 and 4.95 ± 0.91 %ID/g (percentage injected dose per gram) at the 15-min time point for the 64Cu-CB-TE2A and 64Cu-DOTA radioconjugates, respectively. At the 24-h time point, liver uptake was substantially reduced for the 64Cu-CB-TE2A radioconjugate (0.21 ± 0.06 %ID/g) compared with the 64Cu-DOTA radioconjugate (7.80 ± 1.51 %ID/g). The 64Cu-CB-TE2A-8-AOC- BBN(7-14)NH2 radioconjugate demonstrated significant clearance, 98.60 ± 0.28 %ID, from the mouse at 24 h after injection. In contrast, only 67.84 ± 5.43 %ID of the 64Cu activity was excreted using the 64Cu-DOTA-8-AOC-BBN(7-14)NH2 radioconjugate because of nontarget retention. Conclusion: The pharmacokinetic and small-animal PET/CT studies demonstrate significantly improved nontarget tissue clearance for the 64Cu-CB-TE2A8-AOC-BBN(7-14)NH2. This is attributed to the improved in vivo stability of the 64Cu-CB-TE2A chelate complex as compared with the 64Cu-DOTA chelate complex.

AB - The BB2 receptor subtype, of the bombesin family of receptors, has been shown to be highly overexpressed in a variety of human tumors, including prostate cancer. Bombesin (BBN), a 14-amino acid peptide, has been shown to target the BB2 receptor with high affinity. 64Cu (half-life = 12.7 h, β+: 18%, Eβ+max = 653 keV; β-: 37%, Eβ-max = 578 keV) is a radioisotope that has clinical potential for application in both diagnostic imaging and radionuclide therapy. Recently, new chelation systems such as 1,4,8,11-tetraazabicyclo[6.6.2] hexadecane-4,11-diacetic acid (CB-TE2A) have been reported to significantly stabilize the 64Cu radiometal in vivo. The increased stability of the 64Cu-CB-TE2A chelate complex has been shown to significantly reduce nontarget retention compared with tetraazamacrocycles such as 1,4,7,10-tetraazacyclodoadecane-N,N′,N″,N‴-tetraacetic acid (DOTA). The aim of this study was to determine whether the CB-TE2A chelation system could significantly improve the in vivo stability of 64Cu bombesin analogs. The study directly compares 64Cu bombesin analogs using the CB-TE2A and DOTA chelation systems in a prostate cancer xenograft SCID (severely compromised immunodeficient) mouse model. Methods: The CB-TE2A-8-AOC-BBN(7-14)NH2 and DOTA-8-AOC-BBN(7-14) NH2 conjugates were synthesized and radiolabeled with 64Cu. The receptor-binding affinity and internalization profile of each metallated conjugate was evaluated using PC-3 cells. Pharmacokinetic and small-animal PET/CT studies were performed using female SCID mice bearing PC-3 xenografts. Results: In vivo BB2 receptor targeting was confirmed by tumor uptake values of 6.95 ± 2.27 and 4.95 ± 0.91 %ID/g (percentage injected dose per gram) at the 15-min time point for the 64Cu-CB-TE2A and 64Cu-DOTA radioconjugates, respectively. At the 24-h time point, liver uptake was substantially reduced for the 64Cu-CB-TE2A radioconjugate (0.21 ± 0.06 %ID/g) compared with the 64Cu-DOTA radioconjugate (7.80 ± 1.51 %ID/g). The 64Cu-CB-TE2A-8-AOC- BBN(7-14)NH2 radioconjugate demonstrated significant clearance, 98.60 ± 0.28 %ID, from the mouse at 24 h after injection. In contrast, only 67.84 ± 5.43 %ID of the 64Cu activity was excreted using the 64Cu-DOTA-8-AOC-BBN(7-14)NH2 radioconjugate because of nontarget retention. Conclusion: The pharmacokinetic and small-animal PET/CT studies demonstrate significantly improved nontarget tissue clearance for the 64Cu-CB-TE2A8-AOC-BBN(7-14)NH2. This is attributed to the improved in vivo stability of the 64Cu-CB-TE2A chelate complex as compared with the 64Cu-DOTA chelate complex.

KW - BB2 receptor

KW - Bombesin

KW - Cu

KW - Preclinical

KW - Prostate cancer

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JO - Journal of Nuclear Medicine

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