Copper chelates as probes of biological systems: Stable copper complexes with a macrocyclic bifunctional chelating agent

doi:10.1016/0003-2697(85)90653-0

Analytical Biochemistry

Volume 148, Issue 1, July 1985, Pages 249-253

https://doi.org/10.1016/0003-2697(85)90653-0 Get rights and content

Abstract

Monoclonal antibodies tagged with chelated metal ions have numerous potential applications. Here we report the synthesis of a new “bifunctional” metal chelator, 6(p-bromoacetamidobenzyl)-1,4,8,11-tetraazacyclotetradecane-N,N′,N″,N‴-tetraacetic acid, which can be covalently attached to proteins and which binds copper stably in human serum under physiological conditions. In contrast, other reagents based on ethylenediaminetetraacetic acid or diethylenetriaminepentaacetic acid rapidly lose copper to serum albumin under the same conditions.

References (19)

C.F. Meares et al.
Anal. Biochem
(1984)
I. Tabushi et al.
Tetrahedron Lett
(1977)
H. Stetter et al.
Tetrahedron
(1981)
R. Delgado et al.
Talanta
(1982)
C.F. Meares et al.
Acc. Chem. Res
(1984)
S.J. DeNardo et al.
I. Bertini et al.
A. Hanaki et al.
Chem. Pharm. Bull
(1978)
A.G. Bearn et al.

There are more references available in the full text version of this article.

Cited by (199)

Binuclear Co(II) complexes with macrocycle and carboxylato ligands: structure, cytotoxicity and thermal behavior
2021, Journal of Molecular Structure
Citation Excerpt :
The binding diversity of the macrocyclic ligand cyclam (1,4,8,11-tetraazacyclotetradecane) and its derivatives to different metal cations allows their application as biological models for better understanding of the metal protein functions [1, 2], catalysts for CO2 reduction [3], corrosion inhibitors [4, 5], antitumor [6], antiviral (including HIV activity) [7, 8], antibacterial, antifungal or antimalarial agents [9–13].
In vitro cytotoxic evaluation, formation constants and thermal stability of four mixed-ligand Co(II) complexes with tpmc = N,N',N",N'"-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane and carboxylate/dicarboxylate co-ligands of formulas [Co₂(benz)₂tpmc](ClO₄)₂•3H₂O (1), benz^– = benzoate anion; [Co₂(L)tpmc](ClO₄)₂•nH₂O, L = pht^2– (phthalate dianion), n=2 (2), L = ipht^2– (isophthalate dianion), n=4 (3) and L = tpht^2–(terephthalate dianion), n=4 (4) are reported. The stoichiometric composition of the compounds in the solution were determined spectrophotometrically using Job's methods. Formation constants, K and Gibbs free energy, ΔG values were calculated. The thermal behavior of the complexes was investigated by simultaneous TG/DSC and TG – MS measurements. The cytotoxic effect of the complexes, the free ligands, the DMSO solvent and cis-platin, as referent cytostatic drug, was evaluated on Human cervix adenocarcinoma (HeLa), human melanoma (Fem-x) and human colon carcinoma (LS174) cell lines. The IC50 values were between 12.7–42.3 μM. The first crystal structure determination of the Co(II) complex [Co₂(µ-pht)tpmc](ClO₄)₂•H₂O with boat conformation of tpmc ligand, was also done. The complex crystallizes in monoclinic crystal system, C2/c space group. The geometries around both Co(II) atoms are highly distorted octahedral. The Co(II) ions exhibit CoN₄O₂ coordination environments with the four nitrogen donor atoms of the tpmc ligand and two oxygen atoms belonging to the one carboxylate group of pht²⁻ ligand. The carboxylate groups of pht²⁻ are coordinated in an endo-bidentate mode. The tpmc ligand adopted a boat conformation in which the two coordinated Co(II) atoms are located on the same side of the ring, with Co•••Co distance amounting 5.4799(5) Å.
Targeted Antibodies and Peptides
2021, Molecular Imaging: Principles and Practice
Radiolabeled antibodies and peptides have been widely used for molecular imaging and targeted radiopharmaceutical therapy over the course of many decades, for the purposes of detection and treatment of catastrophic diseases, mainly cancer. Although these agents were initially expected to be “magic bullets” for targeting cancer, both antibodies and peptides have major, characteristic limitations. Thus, considerable effort has been placed on modification of these agents to improve pharmacokinetics, tumor uptake, and whole-body clearance.
Monoclonal antibodies typically have high tumor uptake; however, their long residence time in blood and slow and uneven uptake in tumors can compromise imaging contrast and result in dose-limiting bone marrow toxicity associated with radioimmunotherapy. Strategies designed to overcome these barriers have included the engineering of antibody fragments and smaller, nonnatural constructs.
On the other hand, radioactive peptides typically target tumors more rapidly and have more uniform intratumoral distributions, with concomitant and rapid elimination of the agent via renal excretion. These properties often provide superior imaging contrast. However, tumor uptake of peptides is typically lower than that of antibodies, and renal clearance may result in toxicity to the kidneys during radiopharmaceutical therapy. Thus, the search for improvements in peptide targeting often focuses on the development of pharmacokinetic modifiers.
Antibody pretargeting is an approach designed to combine the favorable properties of both antibodies and peptides, while eliminating the undesired effects of each. In pretargeting, a nonradioactive antibody is administered first and allowed to reach its maximum tumor uptake. Then a radioactive small molecule that binds with high affinity and specificity to the antibody is given subsequently. This strategy is intended to combine the high tumor uptake of antibodies with the rapid elimination of small molecules, in an effort to improve imaging contrast, normal organ toxicity, and therapeutic efficacy.
Recent advancements in the use of antibodies and peptides for cancer imaging and therapy include targeted magnetic contrast agents and nanoparticle-based platforms. There is also widespread interest in optical technologies, with the application of antibodies and peptides conjugated to dyes or quantum dots for fluorescence imaging. Taken together, recent progress to expand strategies for antibody- and peptide-based molecular imaging and targeted radiopharmaceutical therapy has the potential to advance detection and treatment of cancers on a molecular level and in a personalized medicine approach.
PET Radiochemistry
2021, Molecular Imaging: Principles and Practice
Nuclear molecular imaging is fueled by a diverse set of radiopharmaceuticals that enable the visualization of biological targets and processes in normal and disease states. Over the last 40–50 years, a rich set of radiochemistry reactions has been amassed to prepare a panoply of radiopharmaceuticals. A diverse set of positron-emitting radionuclides provides an array of physical and chemical properties that may be exploited to radiolabel small molecules to nanoparticles. Carbon, nitrogen, oxygen, and fluorine are elements that are commonly found in biomolecules and drug candidates. These four elements have radioisotopes that are near pure positron emitters with suitable imaging properties. Radiometals, typically with longer half-lives, may be conjugated to molecular agents with similar biological half-life. Creative chemistry approaches enable the preparation of radiopharmaceuticals and labeled drugs for in vivo evaluation. Herein, an overview of positron emission tomography radiochemistry is presented, highlighting the significant advances in the field covering diverse chemical and biological space.
VAPC-1 Targeted <sup>64</sup>Cu-TP3805 kit preparation and its evaluation
2017, Nuclear Medicine and Biology
Citation Excerpt :
Furthermore due to the presence of its crystal-field stabilization energy, 64Cu possesses well-characterized chelation methods [6–8] and is generally less prone to ligand exchange. However the selection of a bifunctional chelating agents (BFCAs) one of the most important criteria for its in vivo stability [9–11]. The majority of BFCAs used for the chelation of “64Cu” have centered on tetraaza-based macrocyles (i.e. DOTA, TETA) [8,12].
Previously, our laboratory has shown that ⁶⁴Cu-TP3805 can specifically target VPAC1 receptors and be used for positron emission tomography (PET) imaging of breast (BC) and prostate cancer (PC) in humans. Present work is aimed at the formulation of a freeze-dried diaminedithiol-peptide (N₂S₂-TP3805) kit and it's evaluation for the preparation of ⁶⁴Cu labeled TP3805. Parameters such as pH, temperature and incubation time were examined that influenced the radiolabeling efficiency and stability of the product.
Kits were prepared under different conditions and radiolabeling efficiency of TP3805 kit was evaluated for a range of pH 3.5–8.5, after addition of ⁶⁴Cu in 30 μl, 0.1 M HCl. Incubation temperature (37-90 °C) and time (30-120 min.) were also investigated. Kits were stored at −10 °C and their long term stability was determined as a function of their radiolabeling efficiency. Further, stability of ⁶⁴Cu-TP3805 complex was evaluated in presence of fetal bovine serum and bovine serum albumin by using SDS polyacrylamide gel electrophoresis. Kits were then used for PET imaging of BC and PC following eIND (101550) and institutional approvals. Specificity of ⁶⁴Cu-TP3805 for VPAC1 was examined with digital autoradiography (DAR) of prostate tissues obtained after prostatectomy, benign prostatic hyperplasia (BPH) tissue, and benign and malignant lymph nodes. Results were compared with corresponding tissue histology.
Radiolabeling efficiency was ≥95% at final pH ~7.2 when incubated at 50 °C for 90 min. Kits were stable up to 18 months when stored at −10 °C, and ⁶⁴Cu-TP3805 complex exhibited excellent stability for up to 4 h at room temperature. ⁶⁴Cu-TP3805 complex did not show any transchelation even after 2 h incubation at 37 °C in 10% FBS as well as in BSA as determined by SDS PAGE analysis. DAR identified ≥95% of malignant lesions 11 new PC lesions, 20 high grade prostatic intraepithelial neoplasia, 2/2 ejaculatory ducts and 5/5 urethra verumontanum not previously identified The malignant lymph nodes were correctly identified by DAR and for 3/3 BPH patients, and 5/5 cysts, DAR was negative. In human BC (n = 19) and PC (n = 26) were imaged with 100% sensitivity.
Availability of ready to use N₂S₂-peptide kits for ⁶⁴Cu labeling is convenient and eliminates possible day to day variation during its routine preparation for clinical use.
Structural Characterization, DFT Analysis and Catalysis by Highly Active Cationic Fe(II)-Cu(I) Complexes in the Green Synthesis of Triazoles in Water
2023, ChemistrySelect
Preclinical Evaluation of hnRNPA2B1 Antibody in Human Triple-Negative Breast Cancer MDA-MB-231 Cells via PET Imaging
2022, Pharmaceutics

View all citing articles on Scopus

^☆: Supported by Research Grants CA 16861 to C.F.M. from the National Cancer Institute and DE-FG03-84ER60233 to S.J.D. from the Department of Energy.

View full text

Copper chelates as probes of biological systems: Stable copper complexes with a macrocyclic bifunctional chelating agent☆

Abstract

Anal. Biochem

Tetrahedron Lett

Tetrahedron

Talanta

Acc. Chem. Res

Chem. Pharm. Bull