Dataset Information

Stabilization Strategies for Linear Minigastrin Analogues: Further Improvements via the Inclusion of Proline into the Peptide Sequence.

ABSTRACT: Minigastrin (MG) analogues, known for their high potential to target cholecystokinin-2 receptor (CCK2R) expressing tumors, have limited clinical applicability due to low enzymatic stability. By introducing site-specific substitutions within the C-terminal receptor-binding sequence, reduced metabolization and improved tumor targeting can be achieved. In this work, the influence of additional modification within the N-terminal sequence has been explored. Three novel 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-conjugated CCK2R ligands with proline substitution at different positions were synthesized. Substitution did not affect CCK2R affinity, and the conjugates labeled with indium-111 and lutetium-177 showed a high enzymatic stability in different incubation media as well as in vivo (57-79% intact radiopeptide in blood of BALB/c mice at 1 h p.i.) combined with enhanced tumor uptake (29-46% IA/g at 4 h in xenografted BALB/c nude mice). The inclusion of Pro contributes significantly to the development of CCK2R ligands with optimal targeting properties for application in targeted radiotherapy.

SUBMITTER: Klingler M

PROVIDER: S-EPMC7734625 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Stabilization Strategies for Linear Minigastrin Analogues: Further Improvements <i>via</i> the Inclusion of Proline into the Peptide Sequence.

Klingler Maximilian M Hörmann Anton A AA Rangger Christine C Desrues Laurence L Castel Hélène H Gandolfo Pierrick P von Guggenberg Elisabeth E

Journal of medicinal chemistry 20201123 23

Minigastrin (MG) analogues, known for their high potential to target cholecystokinin-2 receptor (CCK2R) expressing tumors, have limited clinical applicability due to low enzymatic stability. By introducing site-specific substitutions within the C-terminal receptor-binding sequence, reduced metabolization and improved tumor targeting can be achieved. In this work, the influence of additional modification within the N-terminal sequence has been explored. Three novel 1,4,7,10-tetraazacyclododecane- ...[more]

PMID: 33226806

Similar Datasets

Project description:Self-assembling peptides remain persistently interesting objects for building nanostructures and further assemble into macroscopic structures, e.g. hydrogels, at sufficiently high concentrations. The modulation of self-assembling β-sheet-forming peptide sequences, with a selection from the full library of amino acids, offers unique possibility for rational tuning of the resulting nanostructured morphology and topology of the formed hydrogel networks. In the present work, we explored how a known β-sheet-disassembling amino acid, proline (P), affects the self-assembly and gelation properties of amphipathic peptides. For this purpose, we modified the backbone of a known β-sheet-forming peptide, FEFKFEFK (F8, F = phenylalanine, E = glutamic acid, and K = lysine), with P to form three sequences: FEFKPEFK (FP), FEFKPEFKF (KPE) and FEFEPKFKF (EPK). The replacement of F by P in the hydrophobic face resulted in the loss of the extended β-sheet conformation of the FP peptide and no gelation at concentration as high as 100 mg mL-1, compared to typical 5 mg mL-1 concentration corresponding to F8. However, by retaining four hydrophobic phenylalanine amino acids in the sequences, hydrogels containing a partial β-sheet structure were still formed at 30 mg mL-1 for KPE (pH 4-10) and EPK (pH 2-5). TEM, AFM, small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) revealed that KPE and EPK peptides self-assemble into nanoribbons and twisted nanofibers, respectively. Molecular dynamics confirmed that the single amino acid replacement of F by P prevented the assembly of the FP peptide with respect to the stable β-sheet-forming F8 variant. Moreover, additional prolongation by F in the KPE variant and shuffling of the polar amino acid sequence in the EPK peptide supported aggregation capabilities of both variants in forming distinct shapes of individual aggregates. Although the overall number of amino acids is the same in both KPE and EPK, their shifted charge density (i.e., the chemical environment in which ionic groups reside) drives self-assembly into distinct nanostructures. The investigated structural changes can contribute to new material designs for biomedical applications and provide better understanding in the area of protein folding.

Project description:Nanoparticulate systems have shown great promise in overcoming the considerable trafficking barriers associated with systemic nucleic acid delivery, which must be addressed to unlock the full potential of technologies such as RNAi and gene editing in vivo. In addition to mediating the cytoplasmic delivery of nucleic cargo and shielding it from nuclease degradation and immunostimulation, nucleic-acid-containing nanomaterials delivered intravenously must also be stable in the bloodstream after administration to avoid toxicity and off-target delivery. To this end, the hydrophilic molecule polyethylene glycol (PEG) has been deployed in many different nanoparticle systems to prevent aggregation and recognition by the reticuloendothelial system. However, the optimal strategy for incorporating PEG into self-assembled nucleic acid delivery systems to obtain nanoparticle stability while retaining important functions such as receptor targeting and cargo activity remains unclear. In this work, we develop substantially improved formulations of tumor-penetrating nanocomplexes (TPNs), targeted self-assembled nanoparticles formulated with peptide carriers and siRNA that have been shown to mitigate tumor burden in an orthotopic model of ovarian cancer. We specifically sought to tailor TPNs for intravenous delivery by systematically comparing formulations with three different classes of modular PEG incorporation (namely PEG graft polymers, PEG lipids, and PEGylated peptide), each synthesized using straightforward bioconjugation techniques. We found that the addition of PEG lipids or PEGylated peptide carriers led to the formation of small and stable nanoparticles, but only nanoparticles formulated with PEGylated peptide carriers retained substantial activity in a gene silencing assay. In vivo, this formulation significantly decreased accumulation in off-target organs and improved initial availability in circulation compared to results from the original non-PEGylated particles. Thus, from among a set of candidate strategies, we identified TPNs with admixed PEGylated peptide carriers as the optimal formulation for systemic administration of siRNA on the basis of their performance in a battery of physicochemical and biological assays. Moreover, this optimized formulation confers pharmacologic advantages that may enable further translational development of tumor-penetrating nanocomplexes, highlighting the preclinical value of comparing formulation strategies and the relevance of this systematic approach for the development of other self-assembled nanomaterials.

Project description:Quantum mechanical calculations have been used to investigate how the incorporation of an amino group to the Cbeta- or Cgamma-positions of the pyrrolidine ring affects the intrinsic conformational properties of the proline. Specifically, a conformational study of the N-acetyl-N'-methylamide derivatives of four isomers of aminoproline, which differ not only in the beta- or gamma-position of the substituent but also in its cis or trans relative disposition, has been performed. To further understand the role of the intramolecular hydrogen bonds between the backbone carbonyl groups and the amino side group, a conformational study was also performed on the corresponding four analogues of (dimethylamino)proline. In addition, the effects of solvation on aminoproline and (dimethylamino)proline dipeptides have been evaluated using a self-consistent reaction field model, and considering four different solvents (carbon tetrachloride, chloroform, methanol and water). Results indicate that the incorporation of the amino substituent into the pyrrolidine ring affects the conformational properties, with backbone...side chain intramolecular hydrogen bonds detected when it is incorporated in a cis relative disposition. In general, the incorporation of the amino side group tends to stabilize those structures where the peptide bond involving the pyrrolidine nitrogen is arranged in cis. The aminoproline isomer with the substituent attached to the Cgamma-position with a cis relative disposition is the most stable in the gas phase and in chloroform, methanol and water solutions. Replacement of the amino side group by the dimethylamino substituent produces significant changes in the potential energy surfaces of the four investigated (dimethylamino)proline-containing dipeptides. Thus, these changes affect not only the number of minima, which increases considerably, but also the backbone and pseudorotational preferences. In spite of these effects, comparison of the conformational preferences, i.e., the more favored conformers, calculated for different isomers of aminoproline and (dimethylamino)proline dipeptides showed a high degree of consistency for the two families of compounds.

Dataset Information

Stabilization Strategies for Linear Minigastrin Analogues: Further Improvements via the Inclusion of Proline into the Peptide Sequence.

Publications

Stabilization Strategies for Linear Minigastrin Analogues: Further Improvements <i>via</i> the Inclusion of Proline into the Peptide Sequence.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Stabilization Strategies for Linear Minigastrin Analogues: Further Improvements via the Inclusion of Proline into the Peptide Sequence.

Publications

Stabilization Strategies for Linear Minigastrin Analogues: Further Improvements &lt;i&gt;via&lt;/i&gt; the Inclusion of Proline into the Peptide Sequence.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Stabilization Strategies for Linear Minigastrin Analogues: Further Improvements <i>via</i> the Inclusion of Proline into the Peptide Sequence.