Single-Chain Antibody Conjugated to a Cage Amine Chelator and Labeled with Positron-Emitting Copper-64 for Diagnostic Imaging of Activated Platelets

Alt, Karen; Paterson, Brett M.; Ardipradja, Katie; Schieber, Christine; Buncic, Gojko; Lim, Bryan; Poniger, Stan; Jakoby, Bjoern; Wang, Xiaowei; O’Keefe, Graeme; Tochon-Danguy, Henri; Scott, Andrew M.; Ackermann, Uwe; Peter, Karlheinz; Donnelly, Paul S.; Hagemeyer, Christoph E.

doi:10.1021/mp500209a

Cited by 42 publications

(40 citation statements)

References 40 publications

(70 reference statements)

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“…MeCOSar-NHS-ester (where MeCOsar = 1-methyl-8-NHCO(CH 2 ) 3 CO 2 H-sarcophagine; sarcophagine = 3, 6, 10, 13, 16, 19-hexaazabicyclo[6.6.6]-icosane = sar) as well as the conjugation of the MeCOSar to the scFv were prepared as described previously1750. Briefly, the activated ester, (t-Boc) 4−5 MeCOSar-NHS-ester, was obtained by reacting (t-Boc) 4–5 MeCOSar with 1-ethyl-3-(3-(dimethylamino)-propyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) in dimethylformamide (DMF), followed by purification by silica gel chromatography.…”

Section: Methodsmentioning

confidence: 99%

“…We have previously generated specific single-chain antibodies (scFv) and have shown their unique suitability for imaging of activated platelets in thrombosis and inflammation using various imaging modalities such as ultrasound and MRI121415. Most recently, we attached these scFvs to the sarcophagine bifunctional chelator MeCOSar thus generating an activated platelet targeted 64 Cu radiotracer for PET1617. Sarcophagines are macrobicyclic chelators that are particularly well suited for copper radiopharmaceutical applications because they form extremely stable complexes with 64 Cu with fast complexation kinetics at room temperature, neutral pH and at low concentrations18192021.…”

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confidence: 99%

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Highly Sensitive Detection of Minimal Cardiac Ischemia using Positron Emission Tomography Imaging of Activated Platelets

Ziegler

Alt

Paterson

et al. 2016

Sci Rep

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A reliable method for the diagnosis of minimal cardiac ischemia would meet a strong demand for the sensitive diagnosis of coronary artery disease in cardiac stress testing and risk stratification in patients with chest pain but unremarkable ECGs and biomarkers. We hypothesized that platelets accumulate early on in ischemic myocardium and a newly developed technology of non-invasive molecular PET imaging of activated platelets can thus detect minimal degrees of myocardial ischemia. To induce different degrees of minimal cardiac ischemia, the left anterior descending artery (LAD) was ligated for 10, 20 or 60 min. Mice were injected with a newly generated scFvanti-GPIIb/IIIa-64CuMeCOSar radiotracer, composed of a single-chain antibody that only binds to activated integrin GPIIb/IIIa (αIIbβIII) and thus to activated platelets, and a sarcophagine cage MeCOSar complexing the long half-life PET tracer copper-64. A single PET/CT scan was performed. Evans Blue/TTC staining to detect necrosis as well as classical serological biomarkers like Troponin I and heart-type fatty acid-binding protein (H-FABP) were negative, whereas PET imaging of activated platelets was able to detect small degrees of ischemia. Taken together, molecular PET imaging of activated platelets represents a unique and highly sensitive method to detect minimal cardiac ischemia.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

Highly Sensitive Detection of Minimal Cardiac Ischemia using Positron Emission Tomography Imaging of Activated Platelets

Ziegler

Alt

Paterson

et al. 2016

Sci Rep

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“…There was also significantly higher uptake of scFv anti-LIBS -BCN/alkyne-OEG-64 CuMeCOSar in the injured vessel compared to scFv mut -BCN/alkyne-OEG-64 CuMeCOSar.I naseparate study,a dministration of scFv anti-LIBS (400 mg) 30 min before radiotracer injection to block the binding sites significantly reduced scFv anti-LIBS -BCN-OEG-64 CuMeCOSar binding to the target receptor (Table 1). Furthermore,the mice were placed in asmall-animal PET/CT 30 min post-injection of as ingle dose of scFv anti-LIBS -BCN/ alkyne-OEG-64 CuMeCOSar or scFv mut -BCN/alkyne-OEG-64 CuMeCOSar (3)(4)(5) with the carotid artery set as the region of interest. TheP ET/CT scans showed an accumulation of scFv anti-LIBS -BCN/alkyne-OEG-64 CuMeCOSar in the injured vessel and no significant uptake of scFv mut -BCN/ alkyne-OEG-64 CuMeCOSar confirming the highly specific GPIIb/IIIa mediated binding ( Figure 5B).…”

Section: Methodsmentioning

confidence: 99%

“…[1] Conventional strategies include reacting electrophilic groups such as isothiocyanates and carboxylic acids with the amine group of lysine, [2] or Michael addition with the thiol present in cysteine. [2,5] In contrast, site-specific conjugation provides homogeneity and improved outcomes in the retention of biological function. [2,5] In contrast, site-specific conjugation provides homogeneity and improved outcomes in the retention of biological function.…”

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A Versatile Approach for the Site‐Specific Modification of Recombinant Antibodies Using a Combination of Enzyme‐Mediated Bioconjugation and Click Chemistry

Alt,

Paterson,

Westein

et al. 2015

Angew Chem Int Ed

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A unique two-step modular system for site-specific antibody modification and conjugation is reported. The first step of this approach uses enzymatic bioconjugation with the transpeptidase Sortase A for incorporation of strained cyclooctyne functional groups. The second step of this modular approach involves the azide-alkyne cycloaddition click reaction. The versatility of the two-step approach has been exemplified by the selective incorporation of fluorescent dyes and a positron-emitting copper-64 radiotracer for fluorescence and positron-emission tomography imaging of activated platelets, platelet aggregates, and thrombi, respectively. This flexible and versatile approach could be readily adapted to incorporate a large array of tailor-made functional groups using reliable click chemistry whilst preserving the activity of the antibody or other sensitive biological macromolecules.

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“…For example, the conjugate of a single-chain antibody with a monofunctionalized 64 Cu 2+ sarcophaginate (Scheme 17) has been used for diagnostic PET imaging of activated platelets [60]. It accumulated in an injured vessel with high and specific uptake, thus paving the way towards highly sensitive in vivo detection of activated platelets and early diagnosis of acute thrombotic events [60].…”

Section: Cage Complexes For Radiation Therapy and Diagnosticsmentioning

confidence: 99%

Recent advances in biological applications of cage metal complexes

2015

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IntroductionModern technologies heavily rely on the knowledge from different fields of science. Today, novel pharmaceuticals, diagnostic methods and materials, such as biological/non-biological constructs [1], are being constantly produced at the crossroads of biology, materials engineering, biochemistry and synthetic chemistry. Until recently, the main efforts of medicinal chemists have been focused on creating new potent drugs within the realm of organic chemistry; however, over the last decade, the need for pharmaceuticals with improved potency and selectivity has shifted the attention of some researchers towards metal complexes [2]. Advantages they provide over purely organic compounds are structural diversity [3], simple synthesis and specific characteristics, such as redox [4], optical [5], catalytic [6], radioactive [7] and magnetic [8], induced by a metal ion.Whereas some medicinal applications of metal complexes, e.g. catalytic transformations in living organisms [9], require the metal ion to be easily accessible by biological environment, other approaches may benefit from its total isolation, which may help to ensure stability of a biologically-active complex by avoiding its decomposition, transmetallation or unwanted coordination. An intuitive strategy in this case is to bury the metal ion inside a three-dimensional ligand, as in cage complexes (clathrochelates [10]). Encapsulation of a transition metal ion leads to complexes with high chemical stability and unusual properties that can be used as molecular scaffolds for new (photo)electronic devices (molecular switches [11], magnetic [12] and electrochromic [13] materials), molecular machines [14], electrocatalysts for hydrogen production [15], metallomacrocycles [16], metalorganic frameworks [16b] and coordination capsules [17]. Biological applications of clathrochelates have been covered previously in 1995 [18] and 2007[19]. This short review summarizes the progress that has been made in this area since then. First, biological aspects of clathrochelates will be addressed for which the role of the metal ion is purely structural, so all their activity owes to the caging ligand. Then applications will be 3 carboranes and metallacarboranes [24] are large and bulky enough to ensure strong multicentered supramolecular binding by van der Waals interactions with large protein molecules. Design of the topological drugs paves the way towards new antitumor and antiviral drug candidates; it is also possible that drug resistance is less likely to develop in this case, if it is caused by enzymatic deactivation of the active compound.Clathrochelate-based xenobiotics, which have neither natural analogs nor structural similarity to biological molecules, are of particular interest. An example of xenobiotics among polyhedral compounds is derivatives of adamantane carbocycle (Figure 1) widely used in drug therapy of Parkinson's and other human viral, dermatological and psychical diseases. The activity of these compounds is usually attributed to the bulky carbocyclic po...

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Single-Chain Antibody Conjugated to a Cage Amine Chelator and Labeled with Positron-Emitting Copper-64 for Diagnostic Imaging of Activated Platelets

Cited by 42 publications

References 40 publications

Highly Sensitive Detection of Minimal Cardiac Ischemia using Positron Emission Tomography Imaging of Activated Platelets

Highly Sensitive Detection of Minimal Cardiac Ischemia using Positron Emission Tomography Imaging of Activated Platelets

A Versatile Approach for the Site‐Specific Modification of Recombinant Antibodies Using a Combination of Enzyme‐Mediated Bioconjugation and Click Chemistry

Recent advances in biological applications of cage metal complexes

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