Bicyclic Peptides Conjugated to an Albumin-Binding Tag Diffuse Efficiently into Solid Tumors

Pollaro, Lisa; Raghunathan, Sandeep; Morales-Sanfrutos, Julia; Angelini, Alessandro; Kontos, Stephan; Heinis, Christian

doi:10.1158/1535-7163.mct-14-0534

Cited by 26 publications

(29 citation statements)

References 26 publications

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“…One significant difference was the higher liver uptake of the Cy7 monomer. An alternative approach to slow clearance is to add an albumin binding peptide sequence through solid-phase synthesis [60], but increased liver uptake due to longer plasma exposure and/or scavenger uptake[75–76] and down-regulation of GLP-1R may not provide any targeting benefit over the more rapidly cleared monomer. In the pancreas, total uptake of 800CW and Cy7 monomers was not statistically different (p = 0.26).…”

Section: Discussionmentioning

confidence: 99%

Quantitative Impact of Plasma Clearance and Down-regulation on GLP-1 Receptor Molecular Imaging

Zhang

Thurber

2015

Mol Imaging Biol

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Purpose Quantitative molecular imaging of beta cell mass (BCM) would enable early detection and treatment monitoring of type-1 diabetes. The glucagon like peptide-1 (GLP-1) receptor is an attractive target due to its beta cell specificity and cell surface location. We quantitatively investigated the impact of plasma clearance and receptor internalization on targeting efficiency in healthy B6 mice. Procedures Four exenatide-based probes were synthesized that varied in molecular weight, binding affinity, and plasma clearance. The GLP-1 receptor internalization rate and in vivo receptor expression were quantified. Results Receptor internalization (54,000 receptors/cell in vivo) decreased significantly within minutes, reducing the benefit of a slower clearing agent. The multimers and albumin binding probes had higher kidney and liver uptake, respectively. Conclusions Slow plasma clearance is beneficial for GLP-1 receptor peptide therapeutics. However, for exendin-based imaging of islets, downregulation of the GLP-1 receptor and non-specific background uptake result in a higher TBR for fast-clearing agents.

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Section: Discussionmentioning

confidence: 99%

Quantitative Impact of Plasma Clearance and Down-regulation on GLP-1 Receptor Molecular Imaging

Zhang

Thurber

2015

Mol Imaging Biol

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“…20,21 Most Cys-conjugation procedures involve the thiol monoalkylation of the residue; however, as mentioned above, in nature Cys residues are often found as disulfide bonds, where they play a key role in the structural conformation of proteins. Although bis-alkylating agents have been widely used for peptide cyclization and labelling, [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] only a few examples of bis-alkylation of a previously reduced pair of Cys residues of an antibody using a bis-sulfone linker and bromomaleimides have been described in the literature. [39][40][41][42][43] Thus new chemical entities able to preserve the native structure of the antibodies after bioconjugation are needed.…”

Section: ▪ Introductionmentioning

confidence: 99%

Bioconjugation through Mesitylene Thiol Alkylation

et al. 2018

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The design and generation of complex multifunctional macromolecular structures by bioconjugation is a hot topic due to increasing interest in conjugates with therapeutic applications. In this regard, the development of efficient, selective, and safe conjugation methods is a major objective. In this report, we describe the use of the bis(bromomethyl)benzene scaffold as a linker for bioconjugation with special emphasis on antibody conjugation. We first performed the monothioalkylation of 1,3,5-tris(bromomethyl)benzene, which rendered the reactive dibromotrimethylbenzyl derivatives to be used in thiol bis-alkylation. Next, we introduced into the linker either a bis(Cys)-containing peptide or anti-CD4 and -CD13 monoclonal antibodies, previously subjected to partial reduction of disulfide bonds. Mass spectrometry, UV-vis spectra, and SDS-PAGE experiments revealed that this bis-alkylating agent for bioconjugation preserved both antibody integrity and antibody-antigen binding affinity, as assessed by flow cytometry. Taken together, our results show that the mesitylene scaffold is a suitable linker for thiol-based bioconjugation reactions. This linker could be applicable in the near future for the preparation of antibody drug conjugates.

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“…Many lipophilic agents have been utilized to increase plasma protein binding of peptides including fatty acids 41 , diphenyl cyclohexanol 42 , and lipophilic fluorescent dyes 43, 44 . Alternatively, albumin-binding peptides can be used for a similar purpose 45–47 , although these peptides would also be subject to protease degradation following subcutaneous delivery. Alpha helix stabilization may alter absorption and clearance rates in addition to improving protease stability.…”

Section: Introductionmentioning

confidence: 99%

A Helix-Stabilizing Linker Improves Subcutaneous Bioavailability of a Helical Peptide Independent of Linker Lipophilicity

2016

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Stabilized peptides address several limitations to peptide-based imaging agents and therapeutics such as poor stability and low affinity due to conformational flexibility. There is also active research in developing these compounds for intracellular drug targeting, and significant efforts have been invested to determine the effects of helix stabilization on intracellular delivery. However, much less is known about the impact on other pharmacokinetic parameters such as plasma clearance and bioavailability. We investigated the effect of different fluorescent helix-stabilizing linkers with varying lipophilicity on subcutaneous (SC) bioavailability using the glucagon-like peptide-1 (GLP-1) receptor ligand exendin as a model system. The stabilized peptides showed significantly higher protease resistance and increased bioavailability independent of linker hydrophilicity, and all subcutaneously delivered conjugates were able to successfully target the islets of Langerhans with high specificity. The lipophilic peptide variants had slower absorption and plasma clearance than their respective hydrophilic conjugates, and the absolute bioavailability was also lower likely due to the longer residence times in the skin. The ease and efficiency of double-click helix stabilization chemistries is a useful tool for increasing the bioavailability of peptide therapeutics, many of which suffer from rapid in vivo protease degradation. Helix stabilization using linkers of varying lipophilicity can further control SC absorption and clearance rates to customize plasma pharmacokinetics.

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Bicyclic Peptides Conjugated to an Albumin-Binding Tag Diffuse Efficiently into Solid Tumors

Cited by 26 publications

References 26 publications

Quantitative Impact of Plasma Clearance and Down-regulation on GLP-1 Receptor Molecular Imaging

Quantitative Impact of Plasma Clearance and Down-regulation on GLP-1 Receptor Molecular Imaging

Bioconjugation through Mesitylene Thiol Alkylation

A Helix-Stabilizing Linker Improves Subcutaneous Bioavailability of a Helical Peptide Independent of Linker Lipophilicity

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