A multivalent approach of imaging probe design to overcome an endogenous anion binding competition for noninvasive assessment of prostate specific membrane antigen

Guiyang Hao, Amit Kumar, Timothy Dobin, Orhan K. Öz, Jer Tsong Hsieh, Xiankai Sun

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6 Citations (Scopus)

Abstract

2[(3-Amino-3-carboxypropyl)(hydroxy)(phosphinyl)methyl]pentane-1,5-dioic acid) (GPI) is a highly potent inhibitor of prostate specific membrane antigen (PSMA) with a rapid in vivo clearance profile from nontarget organs including kidneys, but its use for imaging of PSMA is impeded by an endogenous anion (serum phosphate) competition, which compromises its specific binding to the antigen. Multipresentation of a targeting molecule on a single entity has been recognized as a practical way for imaging sensitivity enhancement. Herein, we demonstrate a multivalent approach based on a 64Cu-specific bifunctional chelator scaffold to overcome the endogenous phosphate competition thus enabling the utility of GPI conjugates for in vivo detection of PSMA and imaging quantification. Both monomeric (H2CBT1G) and dimeric (H 2CBT2G) conjugates were synthesized and labeled with 64Cu for in vitro and in vivo evaluations. A 4-fold enhancement of PSMA binding affinity was observed for H2CBT2G as compared to H2CBT1G from the PSMA competitive binding assays performed on LNCaP cells. In vivo PET imaging studies were conducted on mouse xenograft models established with a PSMA+ cell line, LNCaP, and PSMA- PC3 and H2009 cell lines. 64Cu-CBT2G showed significantly higher LNCaP tumor uptake than 64Cu-CBT1G at 1, 4, and 24 h postinjection (p.i.) (p < 0.05). In addition, tumor uptake of 64Cu-CBT2G remained steady out to 24 h p.i. (1.46 ± 0.54, 1.12 ± 0.56, and 1.00 ± 0.50% ID/g at 1, 4, and 24 h p.i., respectively), while 64Cu-CBT1G showed a great decrease from 1 to 4 h p.i. The PSMA imaging specificity of both H 2CBT1G and H2CBT2G was demonstrated by their low uptake in PSMA- tumors (PC3 and H2009) and further confirmed by a significant signal reduction in PSMA+ LNCaP tumors in the blockade study. In addition, the LNCaP tumor uptake (% ID/g) of 64Cu-CBT2G was found to be in a positive linear correlation with the tumor size (R2 = 0.92, 0.94, and 0.93 for 1 h, 4 h, and 24 h p.i.). This may render the probe with potential application in the management of patients with prostate cancer.

Original languageEnglish (US)
Pages (from-to)2975-2985
Number of pages11
JournalMolecular Pharmaceutics
Volume10
Issue number8
DOIs
StatePublished - Aug 5 2013

Fingerprint

Anions
Neoplasms
Phosphates
human glutamate carboxypeptidase II
Cell Line
Competitive Binding
Chelating Agents
Heterografts
Prostatic Neoplasms
Kidney
Antigens
Acids
Serum

Keywords

  • Cu
  • multivalency
  • PET
  • prostate cancer
  • PSMA

ASJC Scopus subject areas

  • Pharmaceutical Science
  • Molecular Medicine
  • Drug Discovery

Cite this

@article{37ce1f1e908f47458bc8dd750c448e1d,
title = "A multivalent approach of imaging probe design to overcome an endogenous anion binding competition for noninvasive assessment of prostate specific membrane antigen",
abstract = "2[(3-Amino-3-carboxypropyl)(hydroxy)(phosphinyl)methyl]pentane-1,5-dioic acid) (GPI) is a highly potent inhibitor of prostate specific membrane antigen (PSMA) with a rapid in vivo clearance profile from nontarget organs including kidneys, but its use for imaging of PSMA is impeded by an endogenous anion (serum phosphate) competition, which compromises its specific binding to the antigen. Multipresentation of a targeting molecule on a single entity has been recognized as a practical way for imaging sensitivity enhancement. Herein, we demonstrate a multivalent approach based on a 64Cu-specific bifunctional chelator scaffold to overcome the endogenous phosphate competition thus enabling the utility of GPI conjugates for in vivo detection of PSMA and imaging quantification. Both monomeric (H2CBT1G) and dimeric (H 2CBT2G) conjugates were synthesized and labeled with 64Cu for in vitro and in vivo evaluations. A 4-fold enhancement of PSMA binding affinity was observed for H2CBT2G as compared to H2CBT1G from the PSMA competitive binding assays performed on LNCaP cells. In vivo PET imaging studies were conducted on mouse xenograft models established with a PSMA+ cell line, LNCaP, and PSMA- PC3 and H2009 cell lines. 64Cu-CBT2G showed significantly higher LNCaP tumor uptake than 64Cu-CBT1G at 1, 4, and 24 h postinjection (p.i.) (p < 0.05). In addition, tumor uptake of 64Cu-CBT2G remained steady out to 24 h p.i. (1.46 ± 0.54, 1.12 ± 0.56, and 1.00 ± 0.50{\%} ID/g at 1, 4, and 24 h p.i., respectively), while 64Cu-CBT1G showed a great decrease from 1 to 4 h p.i. The PSMA imaging specificity of both H 2CBT1G and H2CBT2G was demonstrated by their low uptake in PSMA- tumors (PC3 and H2009) and further confirmed by a significant signal reduction in PSMA+ LNCaP tumors in the blockade study. In addition, the LNCaP tumor uptake ({\%} ID/g) of 64Cu-CBT2G was found to be in a positive linear correlation with the tumor size (R2 = 0.92, 0.94, and 0.93 for 1 h, 4 h, and 24 h p.i.). This may render the probe with potential application in the management of patients with prostate cancer.",
keywords = "Cu, multivalency, PET, prostate cancer, PSMA",
author = "Guiyang Hao and Amit Kumar and Timothy Dobin and {\"O}z, {Orhan K.} and Hsieh, {Jer Tsong} and Xiankai Sun",
year = "2013",
month = "8",
day = "5",
doi = "10.1021/mp4000844",
language = "English (US)",
volume = "10",
pages = "2975--2985",
journal = "Molecular Pharmaceutics",
issn = "1543-8384",
publisher = "American Chemical Society",
number = "8",

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TY - JOUR

T1 - A multivalent approach of imaging probe design to overcome an endogenous anion binding competition for noninvasive assessment of prostate specific membrane antigen

AU - Hao, Guiyang

AU - Kumar, Amit

AU - Dobin, Timothy

AU - Öz, Orhan K.

AU - Hsieh, Jer Tsong

AU - Sun, Xiankai

PY - 2013/8/5

Y1 - 2013/8/5

N2 - 2[(3-Amino-3-carboxypropyl)(hydroxy)(phosphinyl)methyl]pentane-1,5-dioic acid) (GPI) is a highly potent inhibitor of prostate specific membrane antigen (PSMA) with a rapid in vivo clearance profile from nontarget organs including kidneys, but its use for imaging of PSMA is impeded by an endogenous anion (serum phosphate) competition, which compromises its specific binding to the antigen. Multipresentation of a targeting molecule on a single entity has been recognized as a practical way for imaging sensitivity enhancement. Herein, we demonstrate a multivalent approach based on a 64Cu-specific bifunctional chelator scaffold to overcome the endogenous phosphate competition thus enabling the utility of GPI conjugates for in vivo detection of PSMA and imaging quantification. Both monomeric (H2CBT1G) and dimeric (H 2CBT2G) conjugates were synthesized and labeled with 64Cu for in vitro and in vivo evaluations. A 4-fold enhancement of PSMA binding affinity was observed for H2CBT2G as compared to H2CBT1G from the PSMA competitive binding assays performed on LNCaP cells. In vivo PET imaging studies were conducted on mouse xenograft models established with a PSMA+ cell line, LNCaP, and PSMA- PC3 and H2009 cell lines. 64Cu-CBT2G showed significantly higher LNCaP tumor uptake than 64Cu-CBT1G at 1, 4, and 24 h postinjection (p.i.) (p < 0.05). In addition, tumor uptake of 64Cu-CBT2G remained steady out to 24 h p.i. (1.46 ± 0.54, 1.12 ± 0.56, and 1.00 ± 0.50% ID/g at 1, 4, and 24 h p.i., respectively), while 64Cu-CBT1G showed a great decrease from 1 to 4 h p.i. The PSMA imaging specificity of both H 2CBT1G and H2CBT2G was demonstrated by their low uptake in PSMA- tumors (PC3 and H2009) and further confirmed by a significant signal reduction in PSMA+ LNCaP tumors in the blockade study. In addition, the LNCaP tumor uptake (% ID/g) of 64Cu-CBT2G was found to be in a positive linear correlation with the tumor size (R2 = 0.92, 0.94, and 0.93 for 1 h, 4 h, and 24 h p.i.). This may render the probe with potential application in the management of patients with prostate cancer.

AB - 2[(3-Amino-3-carboxypropyl)(hydroxy)(phosphinyl)methyl]pentane-1,5-dioic acid) (GPI) is a highly potent inhibitor of prostate specific membrane antigen (PSMA) with a rapid in vivo clearance profile from nontarget organs including kidneys, but its use for imaging of PSMA is impeded by an endogenous anion (serum phosphate) competition, which compromises its specific binding to the antigen. Multipresentation of a targeting molecule on a single entity has been recognized as a practical way for imaging sensitivity enhancement. Herein, we demonstrate a multivalent approach based on a 64Cu-specific bifunctional chelator scaffold to overcome the endogenous phosphate competition thus enabling the utility of GPI conjugates for in vivo detection of PSMA and imaging quantification. Both monomeric (H2CBT1G) and dimeric (H 2CBT2G) conjugates were synthesized and labeled with 64Cu for in vitro and in vivo evaluations. A 4-fold enhancement of PSMA binding affinity was observed for H2CBT2G as compared to H2CBT1G from the PSMA competitive binding assays performed on LNCaP cells. In vivo PET imaging studies were conducted on mouse xenograft models established with a PSMA+ cell line, LNCaP, and PSMA- PC3 and H2009 cell lines. 64Cu-CBT2G showed significantly higher LNCaP tumor uptake than 64Cu-CBT1G at 1, 4, and 24 h postinjection (p.i.) (p < 0.05). In addition, tumor uptake of 64Cu-CBT2G remained steady out to 24 h p.i. (1.46 ± 0.54, 1.12 ± 0.56, and 1.00 ± 0.50% ID/g at 1, 4, and 24 h p.i., respectively), while 64Cu-CBT1G showed a great decrease from 1 to 4 h p.i. The PSMA imaging specificity of both H 2CBT1G and H2CBT2G was demonstrated by their low uptake in PSMA- tumors (PC3 and H2009) and further confirmed by a significant signal reduction in PSMA+ LNCaP tumors in the blockade study. In addition, the LNCaP tumor uptake (% ID/g) of 64Cu-CBT2G was found to be in a positive linear correlation with the tumor size (R2 = 0.92, 0.94, and 0.93 for 1 h, 4 h, and 24 h p.i.). This may render the probe with potential application in the management of patients with prostate cancer.

KW - Cu

KW - multivalency

KW - PET

KW - prostate cancer

KW - PSMA

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U2 - 10.1021/mp4000844

DO - 10.1021/mp4000844

M3 - Article

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