Journal of Peptide Science最新文献

Phage display has emerged as a groundbreaking technique for discovering novel biomolecules with significant applications in cancer diagnosis and therapy. This technique employs genetically engineered bacteriophages to display diverse libraries of peptides on their coat proteins, enabling the identification of candidates through a biopanning process targeting specific cancer markers. Biomolecules identified via phage display are widely used as molecular tools, often labeled with imaging agents or conjugated to nanoparticles for noninvasive tumor imaging. This review provides a comprehensive overview of recent advancements in phage display applications in cancer research over the past 5 years and prominent examples of clinical studies. The analysis underscores the potential of phage display to deliver diagnostic and therapeutic biomolecules, highlighting its promise for future clinical implementation in cancer imaging.

The discovery of novel candidate molecules that may transform cancer treatment carries significant clinical implications. Codesane (COD), an 18-amino acid peptide extracted from the wild bee venom of Colletes daviesanus, is categorized as a cationic α-helical amphipathic antimicrobial peptide. COD, produced via solid-phase peptide synthesis, displayed significant antitumor activity in vitro. However, its application as a drug is restricted by conformational flexibility, poor serum stability, and low selectivity. This research focused on designing, synthesizing, and evaluating a series of stapled COD derivatives by all-hydrocarbon stapling strategy. Compared to the original peptide COD, several of these stapled derivatives showed significant enhancements in α-helicity, serum resistance, antitumor activity, and cell selectivity. Significantly, the stapled derivative COD-5, which possesses high helicity, good serum stability, and favorable selectivity, shows promising potential for novel antitumor drug development, whereas COD-3, characterized by high selectivity and good antitumor activity, serves as a preferred candidate for novel breast cancer therapeutic drugs. These findings provide a solid foundation for developing innovative and highly effective antitumor therapies.

Controlled release systems can enhance the efficacy of therapeutic antibodies, particularly for subcutaneous delivery where high or frequent doses are needed. Herein, we designed a peptide hydrogel that displays the binding motif HWRGWV, which targets the Fc-region of IgG. Release studies of FITC-labeled IgG from gel formulations demonstrated slow-release dependent on the Fc-binding motif's content as expected. However, the slow-release profile was diminished when using unlabeled IgG or the antibody Cetuximab, which lacks FITC. This observation and subsequent experiments show that the FITC label directly interacts with the Fc-binding motif displayed from the peptide nanofiber network to modulate release. Further, hydrogels bearing a scrambled version of the Fc-binding motif provide a similar slow-release profile for IgG-FITC but fast release for unlabeled antibodies, indicating that FITC binding of the Fc-binding motif is not specific in nature. Rather, nonspecific electrostatic and aromatic interactions most likely dictate binding and the observed slow-release kinetics of antibody from the gel. This work highlights the importance of considering fluorophore interactions when developing systems for the controlled release of antibodies and more importantly suggests that fluorophores can be used as affinity tags to control the release of protein from hydrogels with possible applications in theragnostic delivery.

Peptide-based nanomolecular constructs offer great possibilities for designing catalytic molecular systems mimicking enzymes. In this study, we designed three tripeptide catalysts that can possibly mimic hydrolase enzymes, with the objective of systematically verifying the scope of modulating enzymatic activity. Histidine residue was placed at three different locations in Fmoc-tripeptide sequences, thus generating three chemically similar but sequentially different molecules, P1, P2, and P3. From our study, the peptide catalyst P3 has shown maximum catalytic activity with a chromogenic substrate, p-nitrophenyl acetate, that gets hydrolyzed to p-nitrophenol. The catalytic activity has increased with an increase in pH and temperature, though pH dependency cannot be generalized and can vary depending on the reaction mechanism. Importantly, this study successfully demonstrates the possibility of modulating the activity of functional mimics of bioactive molecules by tuning the principal components of functional molecules.

Inhibiting MDM2–p53 interactions is a crucial therapeutic strategy in cancer treatment, as it can restore the tumor suppressor activity of p53 and inhibit tumor progression. Peptide inhibitors have shown promise in targeting this interaction; however, their optimization for in vivo use often encounters challenges, particularly in cellular uptake. The present study addresses this limitation by identifying cell-penetrating peptides (CPPs) that are predicted to be nontoxic to humans and capable of inhibiting the MDM2–p53 interaction. We utilized a comprehensive CPP database to extract unmodified peptides, focusing on those predicted to be nontoxic. Selected candidates were subjected to molecular docking followed by 500-ns all-atom explicit-solvent molecular dynamics (MD) simulations, performed in triplicates, to evaluate their binding stability and affinity with MDM2. Binding affinity calculations using MM-PBSA, AREA AFFINITY, and PRODIGY revealed that two peptides consistently exhibited stable binding to MDM2 and demonstrated higher affinity compared with the p53 reference fragment. These peptides not only maintained favorable interactions throughout the simulations but also showed strong potential to disrupt MDM2–p53 binding and reactivate p53 function. The findings highlight these peptides as promising nontoxic anticancer agents and provide a strong foundation for the development of peptide-based therapeutics targeting the MDM2–p53 interaction.

In the synthesis of cetrorelix via solid-phase peptide synthesis (SPPS) employing the Fmoc strategy, the racemization of L-arginine and L-serine was effectively minimized to below 0.5%. This reduction was achieved using the coupling agent HATU, the additive HOBt or HOAt, and the base TMP. Racemization was observed during the coupling of Fmoc-L-arginine(Pbf) and Fmoc-O-tert-butyl-L-serine on Rink Amide AM resin. A gradient reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed for the separation of all the structurally closely related cetrorelix isomers. Optimized RP-HPLC conditions identified D-arginine and D-serine isomeric impurities as the closest eluting peaks to the main cetrorelix peak. Controlling these impurities to the lowest possible levels is essential for developing an efficient preparative HPLC purification process for the commercial production of cetrorelix. This stringent control ensures that the final product meets the high standards required for commercial production and therapeutic use.

Therapeutic peptides targeted at various diseases are becoming increasingly relevant for the pharmaceutical industry. Several of these drugs were originally designed by mimicking a segment of a protein of interest. As such, protein mimicry represents a promising strategy both in immunology, for the identification of B- and T-cell epitopes, as well as for the modulation of protein activity, including the disruption of protein–protein interactions (PPIs) and the interference with biological or pathological cellular functions. Several methods have been developed to pinpoint the (binding) epitopes of a protein or the regions responsible for biological activity. One of such strategies is the scanning of the protein or selected domains with synthetic overlapping peptides. As the mechanism of action of a mimetic peptide can be similar to that of the whole protein, this method offers a powerful tool for the investigation of protein function, along with providing a solid basis for the development of therapeutic candidates. This review gives a general overview of different applications of the peptide scanning methodology, describing a comparison of the preparation and use of solid-phase libraries (peptide arrays) with isolated peptide libraries and highlighting their strengths and most common applications.

Stylissamide B was successfully synthesized for the first time using Fmoc solid-phase peptide synthesis (Fmoc-SPPS) followed by cyclization in solution phase. The Fmoc-SPPS process was monitored using the reversible detection method for amino groups (ReD-A method). The linear peptide, Pro-Pro-Ile-Tyr-Pro-Phe-Pro, was cyclized to form stylissamide B. The spectral data obtained were in agreement with previously reported literature, thereby confirming the reliability of the synthetic method.