scholarly journals Enzymatic Methods for the Site-Specific Radiolabeling of Targeting Proteins

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3492
Author(s):  
Cristina Bolzati ◽  
Barbara Spolaore
Keyword(s):  
Nuclear Medicine ◽  
Polypeptide Chain ◽  
Protein Drug ◽  
Native Structure ◽  
Site Specific ◽  
Physiological Conditions ◽  
Drug Conjugates ◽  
Structure And Activity ◽  
Enzymatic Methods

Site-specific conjugation of proteins is currently required to produce homogenous derivatives for medicine applications. Proteins derivatized at specific positions of the polypeptide chain can actually show higher stability, superior pharmacokinetics, and activity in vivo, as compared with conjugates modified at heterogeneous sites. Moreover, they can be better characterized regarding the composition of the derivatization sites as well as the conformational and activity properties. To this aim, several site-specific derivatization approaches have been developed. Among these, enzymes are powerful tools that efficiently allow the generation of homogenous protein–drug conjugates under physiological conditions, thus preserving their native structure and activity. This review will summarize the progress made over the last decade on the use of enzymatic-based methodologies for the production of site-specific labeled immunoconjugates of interest for nuclear medicine. Enzymes used in this field, including microbial transglutaminase, sortase, galactosyltransferase, and lipoic acid ligase, will be overviewed and their recent applications in the radiopharmaceutical field will be described. Since nuclear medicine can benefit greatly from the production of homogenous derivatives, we hope that this review will aid the use of enzymes for the development of better radio-conjugates for diagnostic and therapeutic purposes.

scholarly journals Dual site-specific chemoenzymatic antibody fragment conjugation using CRISPR-based hybridoma engineering

2020 ◽  
Author(s):  
Camille M. Le Gall ◽  
Johan M.S. van der Schoot ◽  
Iván Ramos-Tomillero ◽  
Melek Parlak Khalily ◽  
Floris J. van Dalen ◽  
...  
Keyword(s):  
Antibody Fragment ◽  
Therapeutic Index ◽  
Stable Cell Line ◽  
Hybridoma Cells ◽  
Target Cells ◽  
Site Specific ◽  
Drug Conjugates ◽  
High Yields ◽  
A Site

I.AbstractFunctionalized antibodies and antibody fragments have found applications in the fields of biomedical imaging, theragnostics, and antibody-drug conjugates (ADC). Antibody functionalization is classically achieved by coupling payloads onto lysine or cysteine residues. However, such stochastic strategies typically lead to heterogenous products, bearing a varying number of payloads. This affects bioconjugate efficacy and stability, as well as its in vivo biodistribution, and therapeutic index, while potentially obstructing the binding sites and leading to off-target toxicity. In addition, therapeutic and theragnostic approaches benefit from the possibility to deliver more than one type of cargo to target cells, further challenging stochastic labelling strategies. Thus, bioconjugation methods to reproducibly obtain defined homogenous conjugates bearing multiple different cargo molecules, without compromising target affinity, are in demand. Here, we describe a straightforward CRISPR/Cas9-based strategy to rapidly engineer hybridoma cells to secrete Fab’ fragments bearing two distinct site-specific labelling motifs, which can be separately modified by two different sortase A mutants. We show that sequential genetic editing of the heavy chain (HC) and light chain (LC) loci enables the generation of a stable cell line that secretes a dual tagged Fab’ molecule (DTFab’), which can be easily isolated in high yields. To demonstrate feasibility, we functionalized the DTFab’ with two distinct cargos in a site-specific manner. This technology platform will be valuable in the development of multimodal imaging agents, theragnostics, and next-generation ADCs.

scholarly journals Synthesis of site-specific antibody-drug conjugates by ADP-ribosyl cyclases

2020 ◽  
Vol 6 (23) ◽  
pp. eaba6752 ◽  
Author(s):  
Zhefu Dai ◽  
Xiao-Nan Zhang ◽  
Fariborz Nasertorabi ◽  
Qinqin Cheng ◽  
Jiawei Li ◽  
...  
Keyword(s):  
Growth Factor Receptor ◽  
Reaction Times ◽  
Single Step ◽  
Her2 Positive ◽  
Site Specific ◽  
Antibody Drug Conjugates ◽  
Drug Conjugates ◽  
Antibody Drug

Most of the current antibody-drug conjugates (ADCs) in clinic are heterogeneous mixtures. To produce homogeneous ADCs, established procedures often require multiple steps or long reaction times. The introduced mutations or foreign sequences may cause high immunogenicity. Here, we explore a new concept of transforming CD38 enzymatic activity into a facile approach for generating site-specific ADCs. This was achieved through coupling bifunctional antibody-CD38 fusion proteins with designer dinucleotide-based covalent inhibitors with stably attached payloads. The resulting adenosine diphosphate–ribosyl cyclase–enabled ADC (ARC-ADC) with a drug-to-antibody ratio of 2 could be rapidly generated through single-step conjugation. The generated ARC-ADC targeting human epidermal growth factor receptor 2 (HER2) displays excellent stability and potency against HER2-positive breast cancer both in vitro and in vivo. This proof-of-concept study demonstrates a new strategy for production of site-specific ADCs. It may provide a general approach for the development of a novel class of ADCs with potentially enhanced properties.

scholarly journals Site-Specific Antibody–Drug Conjugates in Triple Variable Domain Fab Format

Biomolecules ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 764 ◽  
Author(s):  
Dobeen Hwang ◽  
Christoph Rader
Keyword(s):  
Tumor Tissue ◽  
In Vitro Cytotoxicity ◽  
Variable Domain ◽  
Site Specific ◽  
Antibody Drug Conjugates ◽  
Drug Conjugates ◽  
Solid Malignancies ◽  
Antibody Drug

The interest in replacing the conventional immunoglobulin G (IgG) format of monoclonal antibodies (mAbs) and antibody–drug conjugates (ADCs) with alternative antibody and antibody-like scaffolds reflects a need to expand their therapeutic utility and potency while retaining their exquisite specificity, affinity, and low intrinsic toxicity. For example, in the therapy of solid malignancies, the limited tumor tissue penetration and distribution of ADCs in IgG format mitigates a uniform distribution of the cytotoxic payload. Here, we report triple variable domain Fab (TVD–Fab) as a new format that affords the site-specific and stable generation of monovalent ADCs without the Fc domain and a drug-to-antibody ratio (DAR) of 2. TVD–Fabs harbor three variable fragment (Fv) domains: one for tumor targeting and two for the fast, efficient, precise, and stable conjugation of two cargos via uniquely reactive lysine residues. The biochemical and in vitro cytotoxicity properties of a HER2-targeting TVD–Fab before and after conjugation to a tubulin inhibitor were validated. In vivo, the TVD–Fab antibody carrier revealed a circulatory half-life of 13.3 ± 2.5 h and deeper tumor tissue distribution compared to our previously reported dual variable domain (DVD)–IgG1 format. Taken together, the TVD–Fab format merits further investigations as an antibody carrier of site-specific ADCs targeting solid malignancies.

scholarly journals In Vitro and In Vivo Evaluation of Cysteine and Site Specific Conjugated Herceptin Antibody-Drug Conjugates

PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e83865 ◽  
Author(s):  
Dowdy Jackson ◽  
John Atkinson ◽  
Claudia I. Guevara ◽  
Chunying Zhang ◽  
Vladimir Kery ◽  
...  
Keyword(s):  
In Vivo Evaluation ◽  
Site Specific ◽  
Antibody Drug Conjugates ◽  
Drug Conjugates ◽  
Antibody Drug

Patient Exposure and Radiation Risk in Bulgarian Diagnostic Nuclear Medicine I. Survey of Diagnostic Nuclear Medicine Procedures in Bulgaria in 1980

1982 ◽  
Vol 21 (03) ◽  
pp. 85-91 ◽  
Author(s):  
R. Poppitz
Keyword(s):  
Nuclear Medicine ◽  
Radiation Risk ◽  
Patient Exposure ◽  
Diagnostic Nuclear Medicine ◽  
Nuklearmedizinische Diagnostik ◽  
Nuclear Medicine Procedures

Um die Strahlenexposition und das Strahlenrisiko für die Bevölkerung durch die nuklearmedizinische Diagnostik in Bulgarien zu ermitteln, wurde eine Erhebung für das Jahr 1980 über die Arten und Anzahl der Applikationen von Radiopharmaka, über die verwendeten Aktivitäten und über die Geschlechts- und Altersverteilung der untersuchten Patienten durchgeführt. Die Gesamtzahl diagnostischer in vivo Applikationen betrug 116418 (davon 40,5% bei Männern und 59,5% bei Frauen), d.h. 13,1 Applikationen per 1000 Einwohner. Die applizierte Gesamtaktivität aller 44 verwendeter Radiopharmaka betrug ca. 2,1 TBq (56 Ci). Die Geschlechts- und Altersverteilung der untersuchten Patienten war ähnlich jener in anderen Ländern: nur 17,4% aller Patienten waren im reproduktionsfähigen Alter, 52,7% waren über 45 Jahre alt. Im Vergleich zu anderen entwickelten Ländern war in Bulgarien im Jahr 1980 der Anteil der 131J-Jodid-Untersuchungen verhältnismäßig hoch.

Patients with fever of unknown origin (FUO): diagnosis by nuclear medicine imaging

2001 ◽  
Vol 40 (03) ◽  
pp. 59-70 ◽  
Author(s):  
W. Becker ◽  
J. Meiler
Keyword(s):  
Nuclear Medicine ◽  
Fever Of Unknown Origin ◽  
Tumor Imaging ◽  
White Blood Cells ◽  
Unknown Origin ◽  
Final Diagnosis ◽  
Recurrent Fever ◽  
Nuclear Medicine Imaging

SummaryFever of unknown origin (FUO) in immunocompetent and non neutropenic patients is defined as recurrent fever of 38,3° C or greater, lasting 2-3 weeks or longer, and undiagnosed after 1 week of appropriate evaluation. The underlying diseases of FUO are numerous and infection accounts for only 20-40% of them. The majority of FUO-patients have autoimmunity and collagen vascular disease and neoplasm, which are responsible for about 50-60% of all cases. In this respect FOU in its classical definition is clearly separated from postoperative and neutropenic fever where inflammation and infection are more common. Although methods that use in-vitro or in-vivo labeled white blood cells (WBCs) have a high diagnostic accuracy in the detection and exclusion of granulocytic pathology, they are only of limited value in FUO-patients in establishing the final diagnosis due to the low prevalence of purulent processes in this collective. WBCs are more suited in evaluation of the focus in occult sepsis. Ga-67 citrate is the only commercially available gamma emitter which images acute, chronic, granulomatous and autoimmune inflammation and also various malignant diseases. Therefore Ga-67 citrate is currently considered to be the tracer of choice in the diagnostic work-up of FUO. The number of Ga-67-scans contributing to the final diagnosis was found to be higher outside Germany than it has been reported for labeled WBCs. F-l 8-2’-deoxy-2-fluoro-D-glucose (FDG) has been used extensively for tumor imaging with PET. Inflammatory processes accumulate the tracer by similar mechanisms. First results of FDG imaging demonstrated, that FDG may be superior to other nuclear medicine imaging modalities which may be explained by the preferable tracer kinetics of the small F-l 8-FDG molecule and by a better spatial resolution of coincidence imaging in comparison to a conventional gamma camera.

Supramolecular Enhancement of Aminoxyl ORCA Contrast Agents

2019 ◽  
Author(s):  
Hamilton Lee ◽  
Jenica Lumata ◽  
Michael A. Luzuriaga ◽  
Candace Benjamin ◽  
Olivia Brohlin ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Side Effects ◽  
Magnetic Resonance ◽  
Tobacco Mosaic Virus ◽  
Contrast Agents ◽  
Single Molecule ◽  
Organic Radical ◽  
Resonance Imaging ◽  
Physiological Conditions

<div><div><div><p>Many contrast agents for magnetic resonance imaging are based on gadolinium, however side effects limit their use in some patients. Organic radical contrast agents (ORCAs) are potential alternatives, but are reduced rapidly in physiological conditions and have low relaxivities as single molecule contrast agents. Herein, we use a supramolecular strategy where cucurbit[8]uril binds with nanomolar affinities to ORCAs and protects them against biological reductants to create a stable radical in vivo. We further over came the weak contrast by conjugating this complex on the surface of a self-assembled biomacromolecule derived from the tobacco mosaic virus.</p></div></div></div>

In-vivo anti-oxidant screening of Tectona grandis extract

2020 ◽  
Vol 9 (1) ◽  
pp. 1-4
Author(s):  
Tamilarasi G P ◽  
Sabarees G
Keyword(s):  
Biochemical Parameters ◽  
Tectona Grandis ◽  
The Body ◽  
Altered Expression ◽  
Physiological Conditions ◽  
Synthetic Drugs ◽  
Significant Difference ◽  
Anti Oxidant ◽  
Radical Generation

Oxidation is an essential reaction in the human body, which determines the expression of proteins in the body. This results in the altered expression like rapid growth resulting in cancers and other disorders. Many synthetic drugs are available in the market that is effective in limiting the free radical generation and the reaction of radicals with cells. Unfortunately, all those synthetic drugs were found to cause side effects and adverse effects in the body. But given the accuracy of the predictability of the results and administration, this research focuses on testing the anti-oxidant efficiency in rat models testing the biochemical parameters. Investigations have also been done on the anti-oxidant activity of Tectona, but every research was concentrated to prove the anti-oxidant activity only. extract had been tested for anti-oxidant activity by estimating various tissue parameters and it showed better activity. As predicted, there is a significant difference in the and results which can be explained are due to the physiological conditions that exist inside the body.

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