bims-cepepe 2025-02-02 papers

bims-cepepe

Biomed News

on Cell-penetrating peptides

Issue of 2025–02–02
twenty papers selected by
Henry Lamb, Queensland University of Technology

Natural Cyclic Peptides: Synthetic Strategies and Biomedical Applications.
Temporal Microenvironment Mapping (μMap) of Intracellular Trafficking Pathways of Cell-Penetrating Peptides Across the Blood-Brain Barrier.
Advances in cyclotide research: bioactivity to cyclotide-based therapeutics.
A quantitative intracellular peptide binding assay reveals recognition determinants and context dependence of short linear motifs.
Specific Rosetta-based protein-peptide prediction protocol allows the design of novel cholinesterase inhibitor peptides.
Advances and prospects of cell-penetrating peptides in tumor immunotherapy.
Late-Stage Minimal Labeling of Peptides and Proteins for Real-Time Imaging of Cellular Trafficking.
pLM4CPPs: Protein Language Model-Based Predictor for Cell Penetrating Peptides.
Development of novel epoxyketone macrocyclic peptidyl proteasome inhibitors through OPA-mediated one-step cyclization of unprotected peptides.
Scoring Conformational Metastability of Macrocyclic Peptides with Binding Pose Metadynamics.
Exploiting novel placental homing peptides for targeted drug delivery in breast Cancer.
Structure-activity relationship of peptide conjugates derived from BP100 and insights into their interactions with lipid membranes by NMR and MD simulations.
A perspective on the application of macrocyclic design strategies in antitumor drugs.
Strategies and Challenges of Cytosolic Delivery of Proteins.
In Situ Bioconjugation of Synthetic Peptides onto Universal Chimeric Antigen Receptor T Cells for Targeted Cancer Immunotherapies.
Targeting Brain Drug Delivery with Macromolecules Through Receptor-Mediated Transcytosis.
Optimization of Single Relaxin B-Chain Peptide Leads to the Identification of R2R01, a Potent, Long-Acting RXFP1 Agonist for Cardiovascular and Renal Diseases.
Lactoferrin conjugated radicicol nanoparticles enhanced drug delivery and cytotoxicity in prostate cancer cells.
Future applications of cyclic antimicrobial peptides in drug delivery.
Outcome of 177Lu-DOTATATE Peptide Receptor Radionuclide Therapy in Progressive Metastatic Neuroendocrine Tumors from a Tertiary Care Center.

Biomedicines. 2025 Jan 20. pii: 240. [Epub ahead of print]13(1):

Natural Cyclic Peptides: Synthetic Strategies and Biomedical Applications.

Devan Buchanan, Shogo Mori, Ahmed Chadli, Siva S Panda.

  Natural cyclic peptides, a diverse class of bioactive compounds, have been isolated from various natural sources and are renowned for their extensive structural variability and broad spectrum of medicinal properties. Over 40 cyclic peptides or their derivatives are currently approved as medicines, underscoring their significant therapeutic potential. These compounds are employed in diverse roles, including antibiotics, antifungals, antiparasitics, immune modulators, and anti-inflammatory agents. Their unique ability to combine high specificity with desirable pharmacokinetic properties makes them valuable tools in addressing unmet medical needs, such as combating drug-resistant pathogens and targeting challenging biological pathways. Due to the typically low concentrations of cyclic peptides in nature, effective synthetic strategies are indispensable for their acquisition, characterization, and biological evaluation. Cyclization, a critical step in their synthesis, enhances metabolic stability, bioavailability, and receptor binding affinity. Advances in synthetic methodologies-such as solid-phase peptide synthesis (SPPS), chemoenzymatic approaches, and orthogonal protection strategies-have transformed cyclic peptide production, enabling greater structural complexity and precision. This review compiles recent progress in the total synthesis and biological evaluation of natural cyclic peptides from 2017 onward, categorized by cyclization strategies: head-to-tail; head-to-side-chain; tail-to-side-chain; and side-chain-to-side-chain strategies. Each account includes retrosynthetic analyses, synthetic advancements, and biological data to illustrate their therapeutic relevance and innovative methodologies. Looking ahead, the future of cyclic peptides in drug discovery is bright. Emerging trends, including integrating computational tools for rational design, novel cyclization techniques to improve pharmacokinetic profiles, and interdisciplinary collaboration among chemists, biologists, and computational scientists, promise to expand the scope of cyclic peptide-based therapeutics. These advancements can potentially address complex diseases and advance the broader field of biological drug development.

Keywords:  biological properties; cyclic peptides; natural products; synthesis

DOI:  https://doi.org/10.3390/biomedicines13010240
bioRxiv. 2025 Jan 18. pii: 2025.01.15.633151. [Epub ahead of print]

Temporal Microenvironment Mapping (μMap) of Intracellular Trafficking Pathways of Cell-Penetrating Peptides Across the Blood-Brain Barrier.

Danielle C Morgan, Steve D Knutson, Chenmengxiao Roderick Pan, David W C MacMillan.

Peptides play critical roles in cellular functions such as signaling and immune regulation, and peptide-based biotherapeutics show great promise for treating various diseases. Among these, cell-penetrating peptides (CPPs) are particularly valuable for drug delivery due to their ability to cross cell membranes. However, the mechanisms underlying CPP-mediated transport, especially across the blood-brain barrier (BBB), remain poorly understood. Mapping intracellular CPP pathways is essential for advancing drug delivery systems, particularly for neurological disorders, as understanding how CPPs navigate the complex environment of the BBB could enable the development of more effective brain-targeted therapies. Here, we leverage a nanoscale proximity labeling technique, termed μMap, to precisely probe the peptide-receptor interactions and intracellular trafficking mechanisms of photocatalyst-tagged CPPs. The unique advantage of the μMap platform lies in the ability to control the timing of light exposure, which enables the collection of time-gated data, depending on when the blue light is applied to the cells. By harnessing this spatiotemporal precision, we can uncover key peptide-receptor interactions and cellular processes, setting the stage for new innovations in drug design and brain-targeted therapies.

DOI: https://doi.org/10.1101/2025.01.15.633151
Mol Divers. 2025 Jan 25.

Advances in cyclotide research: bioactivity to cyclotide-based therapeutics.

Ankita Grover, Sawraj Singh, Sonal Sindhu, Amit Lath, Sanjay Kumar.

  Cyclotides are a class of plant-derived cyclic peptides having a distinctive structure with a cyclic cystine knot (CCK) motif. They are stable molecules that naturally play a role in plant defense. Till date, more than 750 cyclotides have been reported among diverse plant taxa belonging to Cucurbitaceae, Violaceae, Rubiaceae, Solanaceae, and Fabaceae. These native cyclotides exhibit several bioactivities, such as anti-bacterial, anti-HIV, anti-fungal, pesticidal, cytotoxic, and hemolytic activities which have immense significance in agriculture and therapeutics. The general mode of action of cyclotides is related to their structure, where their hydrophobic face penetrates the cell membrane and disrupts it to exhibit anti-microbial, cytotoxic, or hemolytic activities. Thus, the structure-activity relationship is of significance in cyclotides. Further, owing to their, small size, stability, and potential to interact and cross the membrane barrier of cells, they make promising choices for developing peptide-based biologics. However, challenges, such as production complexity, pharmacokinetic limitations, and off-target effects hinder their development. Advancements in cyclotide engineering, such as peptide grafting, ligand conjugation, and nanocarrier integration, heterologous production along with computational design optimization, can help overcome these challenges. Given the potential of these cyclic peptides, the present review focuses on the diversity, bioactivities, and structure-activity relationships of cyclotides, and advancements in cyclotides engineering emphasizing their unique attributes for diverse medical and biotechnological applications.

Keywords:  Bioactivities; Conjugated cyclotides; Cyclic cysteine knot; Cyclotide engineering; Cyclotides; Nanotubes; Peptide-based biologics

DOI:  https://doi.org/10.1007/s11030-025-11113-w
J Biol Chem. 2025 Jan 24. pii: S0021-9258(25)00072-9. [Epub ahead of print] 108225

A quantitative intracellular peptide binding assay reveals recognition determinants and context dependence of short linear motifs.

Mythili S Subbanna, Matthew J Winters, Mihkel Örd, Norman E Davey, Peter M Pryciak.

  Transient protein-protein interactions play key roles in controlling dynamic cellular responses. Many examples involve globular protein domains that bind to peptide sequences known as Short Linear Motifs (SLiMs), which are enriched in intrinsically disordered regions of proteins. Here we describe a novel functional assay for measuring SLiM binding, called Systematic Intracellular Motif Binding Analysis (SIMBA). In this method, binding of a foreign globular domain to its cognate SLiM peptide allows yeast cells to proliferate by blocking a growth arrest signal. A high-throughput application of the SIMBA method involving competitive growth and deep sequencing provides rapid quantification of the relative binding strength for thousands of SLiM sequence variants, and a comprehensive interrogation of SLiM sequence features that control their recognition and potency. We show that multiple distinct classes of SLiM-binding domains can be analyzed by this method, and that the relative binding strength of peptides in vivo correlates with their biochemical affinities measured in vitro. Deep mutational scanning provides high-resolution definitions of motif recognition determinants and reveals how sequence variations at non-core positions can modulate binding strength. Furthermore, mutational scanning of multiple parent peptides that bind human tankyrase ARC or YAP WW domains identifies distinct binding modes and uncovers context effects in which the preferred residues at one position depend on residues elsewhere. The findings establish SIMBA as a fast and incisive approach for interrogating SLiM recognition via massively parallel quantification of protein-peptide binding strength in vivo.

Keywords:  cyclin-dependent kinase (CDK); high-throughput screening (HTS); intrinsically disordered protein; ligand-binding protein; mutagenesis; peptides; phosphorylation; protein motif; protein-protein interaction; yeast

DOI:  https://doi.org/10.1016/j.jbc.2025.108225
Bioorg Chem. 2025 Jan 22. pii: S0045-2068(25)00082-3. [Epub ahead of print]156 108202

Specific Rosetta-based protein-peptide prediction protocol allows the design of novel cholinesterase inhibitor peptides.

Ivan Sanchis, Florencia Aimaretti, Matias Lupotti, Alvaro Rietmann, José Dias, Xavier Brazzolotto, Roque Spinelli, Álvaro S Siano.

  The search for novel cholinesterase inhibitors is essential for advancing treatments for neurodegenerative disorders such as Alzheimer's disease (AD). In this study, we employed the Rosetta pepspec module, originally developed for designing peptides targeting protein-protein interactions, to design de novo peptides targeting the peripheral aromatic site (PAS) of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). A total of nine peptides were designed for human AChE (hAChE), T. californica AChE (TcAChE), and human BChE (hBChE). These peptides were synthesized using Fmoc-SPPS and tested in vitro using Ellman's reaction to evaluate their inhibitory potency. Peptide 11tA, designed for TcAChE, exhibited potent inhibition of hAChE (IC50 = 1.21 ± 0.25 µM) and demonstrated strong antioxidant activity against DPPH radicals and lipid peroxidation, making it a promising multitherapeutic candidate for AD. Peptide 11hB, designed for hBChE, showed the highest inhibitory activity against hBChE, with a Ki of 12.69 ± 1.27 µM, making it the most potent natural amino acid peptide reported against hBChE. The computational protocol effectively distinguished the specific characteristics of each enzyme target. Toxicity assessments, including hemolysis tests and A. salina lethality assays, revealed no toxic effects at low concentrations, further supporting the potential of these peptides for peptide-based drug development in AD. This study underscores the growing potential of peptides as alternatives to small-molecule drugs. It demonstrates that computational protocols for protein-protein interactions can be successfully adapted to design high-affinity peptide inhibitors.

Keywords:  Cholinesterase inhibitor; De novo design; Peptide inhibitor; Rosetta modeling

DOI:  https://doi.org/10.1016/j.bioorg.2025.108202
Sci Rep. 2025 Jan 27. 15(1): 3392

Advances and prospects of cell-penetrating peptides in tumor immunotherapy.

Di Yang, Baorui Liu, Huizi Sha.

  Cell-penetrating peptides (CPPs) have been shown to have superior material transport ability because poor infiltration of activated lymphocytes into tumors is one of the crucial factors limiting the therapeutic effect of tumor immunotherapy. Numerous studies have investigated the potential application of CPPs in tumor immunotherapy. This review delves into the crucial role that CPPs play in enhancing tumor immunotherapy, emphasizing their impact on various immunotherapy strategies, such as cytokine therapy, adoptive cell therapy, cancer vaccines, and immune checkpoint inhibitors. We also discuss the practical application challenges associated with enhancing the efficiency of CPPs in terms of their stability and targeting ability. In conclusion, the combination of CPPs with tumor immunotherapy is a promising strategy that has potential for precision administration and requires further research for optimal implementation.

Keywords:  Cell-penetrating peptides; Tumor immunotherapy; Tumor-targeted peptide; Vaccine

DOI:  https://doi.org/10.1038/s41598-025-86130-8
ACS Cent Sci. 2025 Jan 22. 11(1): 66-75

Late-Stage Minimal Labeling of Peptides and Proteins for Real-Time Imaging of Cellular Trafficking.

Ferran Nadal-Bufi, Raj V Nithun, Fabio de Moliner, Xiaoxi Lin, Shaimaa Habiballah, Muhammad Jbara, Marc Vendrell.

The cellular uptake routes of peptides and proteins are complex and diverse, often handicapping therapeutic success. Understanding their mechanisms of internalization requires chemical derivatization with approaches that are compatible with wash-free and real-time imaging. In this work, we developed a new late-stage labeling strategy for unprotected peptides and proteins, which retains their biological activity while enabling live-cell imaging of uptake and intracellular trafficking. Benzo-2,1,3-thiadiazoles were selectively incorporated into Cys residues of both linear and cyclic peptides via Pd-mediated arylation with good yields and high purities. The resulting labeled peptides are chemically stable under physiological conditions and display strong fluorogenic character for wash-free imaging studies. We utilized this approach to prepare native-like analogues of cell-penetrating peptides and performed time-course analysis of their internalization routes in live cells by fluorescence lifetime imaging. Furthermore, we applied our strategy to label the chemokine protein mCCL2 and monitor its internalization via receptor-mediated endocytosis in live macrophages. This study provides a straightforward strategy for late-stage fluorogenic labeling of intact peptides and small proteins and direct visualization of dynamic intracellular events.

DOI: https://doi.org/10.1021/acscentsci.4c01249
J Chem Inf Model. 2025 Jan 29.

pLM4CPPs: Protein Language Model-Based Predictor for Cell Penetrating Peptides.

Nandan Kumar, Zhenjiao Du, Yonghui Li.

Cell-penetrating peptides (CPPs) are short peptides capable of penetrating cell membranes, making them valuable for drug delivery and intracellular targeting. Accurate prediction of CPPs can streamline experimental validation in the lab. This study aims to assess pretrained protein language models (pLMs) for their effectiveness in representing CPPs and develop a reliable model for CPP classification. We evaluated peptide embeddings generated from BEPLER, CPCProt, SeqVec, various ESM variants (ESM, ESM-2 with expanded feature set, ESM-1b, and ESM-1v), ProtT5-XL UniRef50, ProtT5-XL BFD, and ProtBERT. We developed pLM4CCPs, a novel deep learning architecture using convolutional neural networks (CNNs) as the classifier for binary classification of CPPs. pLM4CCPs demonstrated superior performance over existing state-of-the-art CPP prediction models, achieving improvements in accuracy (ACC) by 4.9-5.5%, Matthews correlation coefficient (MCC) by 9.3-10.2%, and sensitivity (Sn) by 14.1-19.6%. Among all the tested models, ESM-1280 and ProtT5-XL BFD demonstrated the highest overall performance on the kelm data set. ESM-1280 achieved an ACC of 0.896, an MCC of 0.796, a Sn of 0.844, and a specificity (Sp) of 0.978. ProtT5-XL BFD exhibited superior performance with an ACC of 0.901, an MCC of 0.802, an Sn of 0.885, and an Sp of 0.917. pLM4CCPs combine predictions from multiple models to provide a consensus on whether a given peptide sequence is classified as a CPP or non-CPP. This approach will enhance prediction reliability by leveraging the strengths of each individual model. A user-friendly web server for bioactivity predictions, along with data sets, is available at https://ry2acnp6ep.us-east-1.awsapprunner.com. The source code and protocol for adapting pLM4CPPs can be accessed on GitHub at https://github.com/drkumarnandan/pLM4CPPs. This platform aims to advance CPP prediction and peptide functionality modeling, aiding researchers in exploring peptide functionality effectively.

DOI: https://doi.org/10.1021/acs.jcim.4c01338
Bioorg Chem. 2025 Jan 18. pii: S0045-2068(25)00060-4. [Epub ahead of print]156 108180

Development of novel epoxyketone macrocyclic peptidyl proteasome inhibitors through OPA-mediated one-step cyclization of unprotected peptides.

Gongruixue Zeng, Gaoya Xu, Lixin Gao, Xiaoli Zheng, Xinglong Chi, Zheyuan Shen, Yu Cao, Jianjun Xi, Jinxin Che, Xiaowu Dong, Yaoli Shi, Jiayi Ma, Chong Zhang, Linghui Zeng, Huajian Zhu, Jiaan Shao, Yubo Zhou, Jia Li, Jiankang Zhang.

  Cyclization is a pivotal strategy for enhancing the drug-like characteristics of polypeptides. To develop potent and metabolically stable proteasome inhibitors, we generated a macrocyclic peptide skeleton using a straightforward and efficient cyclization strategy. Subsequent stability assessments confirmed the practicality of this approach. Leveraging this skeleton, we designed and synthesized a series of epoxyketone macrocyclic peptidyl proteasome inhibitors. Approximately half of these compounds showcased robust inhibitory potency, with IC50 values below 200 nM against chymotrypsin-like (ChT-L, β5) activity. Notably, compounds 6f, 6g, and 6m demonstrated pronounced anti-proliferative activities at low nanomolar concentrations against three hematoma cell lines (RPMI-8226, RS4;11, and MV-4-11) as well as the NCI-H1299 cell line. These findings highlight the potential of these cyclic peptides to bolster the stability of proteasome inhibitors, thereby providing valuable insights for the advancement of innovative proteasome inhibitor therapies.

Keywords:  Anti-cancer activities; Macrocycle; Proteasome inhibitors; Stability

DOI:  https://doi.org/10.1016/j.bioorg.2025.108180
J Chem Inf Model. 2025 Jan 29.

Scoring Conformational Metastability of Macrocyclic Peptides with Binding Pose Metadynamics.

Ryan Dykstra, Dan Sindhikara.

Potency optimization of macrocyclic peptides can include both modifying intermolecular interactions and modifying the conformational stability of the bioactive conformation. However, the number of possible modifications is vast. To identify modifications that enhance the stability of the binding conformations in a cost-effective manner, there is a need for a high-throughput in-silico method that scores the conformational stability of these modified molecules. For the common case where a binding conformation of a similar compound is known, the relative stability of this conformation for a series of compounds can theoretically be estimated by modeling the metastability of the bound state via conformational sampling techniques. Herein, we survey several sampling methods and report solution-state binding pose metadynamics as the most efficient of such sampling methods. In this manuscript, we compare both estimations of metastability from shorter solution-state sampling methods to both experimental affinities and more rigorous sampling methods to properly isolate the conformational effect on potency. In our benchmark calculations on macrocyclic peptide data sets where chemical modifications can be expected to influence the stability of the binding pose, our solution-state binding pose metadynamics workflow, which estimates conformational metastability of the bioactive state, agrees with more rigorous REST2 simulations while using significantly less computational resources. Further, for both the cases where REST2 simulations converge, as well as some others, the binding pose metadynamics metastability estimations correlated well with experimentally measured potencies, suggesting binding pose metadynamics may be an efficient method for quickly estimating the effect of binding pose metastability on potency.

DOI: https://doi.org/10.1021/acs.jcim.4c01408
Nanomedicine. 2025 Jan 22. pii: S1549-9634(25)00004-8. [Epub ahead of print] 102805

Exploiting novel placental homing peptides for targeted drug delivery in breast Cancer.

Abdulaziz A Alobaid, Harmesh Aojula, Richard A Campbell, Lynda K Harris.

  More effective drug formulations are needed to increase the selectivity and efficacy of available chemotherapeutics. We have previously shown that nanoparticles decorated with the tumour homing peptide CGKRK can selectively deliver payloads to the placenta. In this study, we investigated whether two novel placental homing peptides NKGLRNK (NKG) and RSGVAKS (RSG) can be utilized to selectively deliver doxorubicin (DOX) to breast cancer cells. Fluorescence microscopy and flow cytometry showed that NKG and RSG bind to and accumulate in MDA-MB-231 and MCF-7 cells in a time-dependent manner, to a similar extent as CGKRK, but accumulate in healthy MCF-10 A cells to a much lesser degree. NKG- and RSG-decorated liposomes facilitated equivalent delivery of DOX to MDA-MB-231 and MCF-7 cells, with a comparable efficacy to CGKRK-decorated liposomes. These findings suggest that NKG and RSG represent novel breast tumour-binding sequences that could be utilized to develop more efficacious targeted breast cancer therapies.

Keywords:  Breast cancer; Doxorubicin; Homing peptides; Nanoparticles; Targeted delivery

DOI:  https://doi.org/10.1016/j.nano.2025.102805
J Biomol Struct Dyn. 2025 Jan 31. 1-18

Structure-activity relationship of peptide conjugates derived from BP100 and insights into their interactions with lipid membranes by NMR and MD simulations.

Gerard Riesco-Llach, Àngel Oliveras, Sergio Gil-Caballero, Esther Badosa, Anna Bonaterra, Emilio Montesinos, Ferran Feixas, Marta Planas, Lidia Feliu.

  Antimicrobial and plant defence elicitor peptides have received attention on last decades as novel tools to combat bacterial plant diseases. We previously reported a library of peptide conjugates resulting from the combination of an antimicrobial peptide (BP16, BP143, BP387 or BP475) and a plant defence elicitor sequence (flg15, BP13, Pep13 or PIP1). From this library, we selected a set of 14 peptide conjugates including both highly and poorly active sequences and we performed a structure-activity relationship study by NMR and MD simulations. Analysis of their structure by NMR in 30% TFE-d3 and in zwitterionic DPC-d38 and anionic SDS-d25 micelles showed that the presence of an α-helix fragment together with a flexible random coil can be related to a high antibacterial activity and a low hemolysis. In contrast, the sequences with a rigid α-helix structure were low active and highly hemolytic. PRE-NMR experiments in presence of MnCl2 and 16-DSA revealed that the highly active peptides flg15-BP475 and BP100-Pep13 interacted stronger with DPC-d38 micelles than the low active peptide BP13-BP16. In the two former sequences this interaction took place through the α-helix region. From GaMD simulations of BP100-Pep13 conducted in membranes composed of anionic DPPG lipids, after its electrostatic interaction, the peptide flipped and the hydrophobic residues were faced to the membrane triggering its insertion and also causing membrane thinning. Thus, the flexibility and moderate cationicity of BP100-Pep13 seem to be crucial for its biological activity. These findings can help to establish the guidelines for future rational design of BP100 derivatives.

Keywords:  Antimicrobial peptides; computational studies; mechanism; micelles; secondary structure

DOI:  https://doi.org/10.1080/07391102.2025.2458328
Bioorg Chem. 2025 Jan 19. pii: S0045-2068(25)00070-7. [Epub ahead of print]156 108190

A perspective on the application of macrocyclic design strategies in antitumor drugs.

Yan-Hong Li, Yu-Kang Lin, Jian-Fan Cai, Zhong-Kai Zou, Pei-Liang Zhao.

  The macrocyclization of inhibitors has become gradually favored as a new approach for drug design in the field of anticancer agents, since the recent approvals of lorlatinib, pacritinib, and repotrectinib, and feasibility of macrocyclic modification to improve inhibitor drug-like properties has also been confirmed. Macrocycles are receiving increasing attention due to their enhanced binding affinity, target selectivity, and pharmacokinetic properties through conformational constraints. Therefore, this review summarizes various strategies for improving drug-like properties in macrocyclization and structural optimization, and reveals that macrocyclization is a new favorable strategy for drug design, aiming to provide insights for the drug discovery in different targets.

Keywords:  Antitumor activity; Kinase inhibitors; Macrocyclic design strategies

DOI:  https://doi.org/10.1016/j.bioorg.2025.108190
J Drug Target. 2025 Jan 25. 1-32

Strategies and Challenges of Cytosolic Delivery of Proteins.

Yuanyuan Li, Baojie Du, Lichao Yu, Hong Luo, Haibo Rong, Xiangdong Gao, Jun Yin.

  The cytosolic delivery of therapeutic proteins represents a promising strategy for addressing diseases caused by protein dysfunction. Despite significant advances, efficient delivery remains challenging due to barriers such as cell membrane impermeability, endosomal sequestration, and protein instability. This review summarizes recent progress in protein delivery systems, including physical, chemical, and biological approaches, with a particular focus on strategies that enhance endosomal escape and targeting specificity. We further discuss the clinical translatability of these approaches and propose future directions for improving delivery efficiency and safety, ultimately unlocking the therapeutic potential of intracellular proteins.

Keywords:  Cytoplasmic delivery; Endosomal escape; Protein delivery vectors; Protein drugs; Targeted delivery

DOI:  https://doi.org/10.1080/1061186X.2025.2458616
ACS Nano. 2025 Jan 27.

In Situ Bioconjugation of Synthetic Peptides onto Universal Chimeric Antigen Receptor T Cells for Targeted Cancer Immunotherapies.

Ian I Cardle, Dylan R Scherer, Michael C Jensen, Suzie H Pun, Drew L Sellers.

  The recent development of modular universal chimeric antigen receptor (CAR) T-cell platforms that use bifunctional adaptor intermediates to redirect engineered T-cell effector function has greatly expanded the capabilities of adoptive T-cell therapy, enabling safer and more comprehensive cancer treatment. However, universal CAR receptor systems rely on unstable transient recognition of tag-coupled intermediates for T-cell activation, and the array of targeting intermediates has been limited to antibodies and small molecules. Addressing these shortcomings, we engineered universal CAR T-cell receptors that can be covalently modified with synthetic biomaterials in vivo by accelerated SpyCatcher003-SpyTag003 chemistry for cancer-cell targeting. SpyCatcher003-modified CARs, nicknamed DB5 CARs, displayed fast, low-nanomolar reaction kinetics with a synthetic αvβ6-binding peptide that incorporates a SpyTag003 peptide via branched peptide synthesis to comprise a bifunctional intermediate. Prearming DB5 CAR T cells or prelabeling target cells with the bifunctional peptide produced selective CD4+ and CD8+ CAR T-cell responses against αvβ6+ cancer cells in vitro. Furthermore, the synthetic targeting intermediate showed robust DB5 CAR T-cell arming in vivo and selectively reduced αvβ6+ tumor progression in a dual flank xenograft model. We demonstrate the versatility and therapeutic potential of "Cyborg" CAR T-cell therapies that utilize synthetic biomaterials to direct CAR T-cell activity via highly selective bioconjugation that occurs in vivo.

Keywords:  CAR T cells; SpyCatcher; immunotherapy; peptides; synthetic adaptors

DOI:  https://doi.org/10.1021/acsnano.4c16824
Pharmaceutics. 2025 Jan 15. pii: 109. [Epub ahead of print]17(1):

Targeting Brain Drug Delivery with Macromolecules Through Receptor-Mediated Transcytosis.

Yuanke Li, Ruiying Liu, Zhen Zhao.

  Brain diseases pose significant treatment challenges due to the restrictive nature of the blood-brain barrier (BBB). Recent advances in targeting macromolecules offer promising avenues for overcoming these obstacles through receptor-mediated transcytosis (RMT). We summarize the current progress in targeting brain drug delivery with macromolecules for brain diseases. This exploration details the transport mechanisms across the BBB, focusing on RMT and its use of natural ligands for drug delivery. Furthermore, the review examines macromolecular ligands such as antibodies, peptides, and aptamers that leverage RMT for effective BBB traversal. Advancements in macromolecules-based delivery systems for brain diseases are summarized, emphasizing their therapeutic potential and limitations. Finally, emerging RMT strategies, including viral vectors, exosomes, and boron neutron capture therapy, are discussed for their precision in brain-targeted treatments. This comprehensive overview underscores the potential of RMT-based approaches to revolutionize brain disease therapy.

Keywords:  CNS; antibody; aptamer; drug delivery; ligands; peptide; receptor-mediated transcytosis

DOI:  https://doi.org/10.3390/pharmaceutics17010109
J Med Chem. 2025 Jan 31.

Optimization of Single Relaxin B-Chain Peptide Leads to the Identification of R2R01, a Potent, Long-Acting RXFP1 Agonist for Cardiovascular and Renal Diseases.

Sergio Mallart, Raffaele Ingenito, Paola Magotti, Alberto Bresciani, Annalise Di Marco, Simone Esposito, Edith Monteagudo, Fulvia Caretti, Laura Orsatti, Alessia Santoprete, Daniela Roversi, Federica Tucci, Maria Veneziano, Denis Brasseur, Xavier Chénedé, Alain Corbier, Laurence Gauzy-Lazo, Vincent Gervat, Frank Marguet, Claire Minoletti, Olivier Pasquier, Bruno Poirier, Aurélien Azam, Bernard Maillère, Elisabetta Bianchi, Philip Janiak, Olivier Duclos, Stephane Illiano.

Peptide 1, a C18 fatty acid-modified single-chain relaxin analogue, was recently identified as a potent, selective, and long-lasting relaxin family peptide receptor 1 (RXFP1) agonist. Further advanced pharmacokinetic profiling of this compound highlighted elevated levels of oxidative metabolism occurring in dogs and mini pigs but only marginally in rats. This study aimed to design long-lasting relaxin analogues with increased stability against metabolic oxidation while securing subnanomolar RXFP1 potency. Key structural elements, including fatty acid chain length, attachment position, and linker structure, were modified to reduce oxidative metabolism and improve pharmacokinetic parameters. Additionally, incorporating α-methyl lysine (Mly) at position 30, alongside other selective sequence mutations, resulted in several analogues with subnanomolar RXFP1 potency and improved duration of action compared to 1. Compound 21 (R2R01) was then selected as a candidate for an in-depth characterization. It is currently undergoing phase 2 clinical development for renal and cardiovascular diseases.

DOI: https://doi.org/10.1021/acs.jmedchem.4c03085
Eur J Pharmacol. 2025 Jan 25. pii: S0014-2999(25)00053-6. [Epub ahead of print] 177300

Lactoferrin conjugated radicicol nanoparticles enhanced drug delivery and cytotoxicity in prostate cancer cells.

Zeinab Kooshan, Srilakshmi Srinivasan, Taskeen Iqbal Janjua, Amirali Popat, Jyotsna Batra.

  Pyruvate dehydrogenase kinase-1 (PDK1) plays a crucial role in cancer cell metabolism by regulating the glycolytic pathway. Although, inhibitors targeting PDK1 have been effective in inhibiting glycolysis in multiple cancers, their lack of selectivity leading to off-target effects limit their therapeutic benefit. Herein, we investigated the inhibitory potential of six PDK1 inhibitors on cellular proliferation, migration, and invasion of androgen-sensitive LNCaP and androgen-negative PC-3 prostate cancer cells. Of the six PDK1 inhibitors, radicicol and dicumarol significantly inhibited cellular proliferation and exhibited lower metabolic activity in both LNCaP and PC-3 metastatic prostate cancer cells. Radicicol was highly effective at lower concentration. Moreover, radicicol significantly inhibited migration and invasion in PC-3 cells. We then developed a lactoferrin nanoparticle (LF-NP) encapsulated with Radicicol (Ra-LF-NP), using a rotary evaporation method. Spheroid assays confirmed the higher inhibitory potential of Ra-LF-NP with a reduction in spheroid area by 80%, and invasiveness compared to radicicol alone. Lactoferrin receptors are overexpressed on the surface of many cancer cells, including prostate cancer. Conjugating radicicol with lactoferrin nanoparticles, potentially enhanced the specific uptake of the drug by prostate cancer cells while minimizing the off-target effects on healthy cells. This targeted therapy approach could lead to improved treatment outcomes and reduced side effects. Our study demonstrated the potential of radicicol delivery by lactoferrin-conjugated nanoparticle as an efficient drug delivery strategy for prostate cancer treatment.

Keywords:  Prostate cancer; chemotherapy; inhibitor; lactoferrin; nanoparticle; pyruvate dehydrogenase kinase-1

DOI:  https://doi.org/10.1016/j.ejphar.2025.177300
Expert Opin Drug Deliv. 2025 Jan 28.

Future applications of cyclic antimicrobial peptides in drug delivery.

Dorna Davani-Davari, Rakesh Kumar Tiwari, Keykavous Parang.

   INTRODUCTION: Cyclic antimicrobial peptides (CAMPs) are gaining attention as promising candidates in advanced drug delivery systems due to their structural stability, resistance to proteolytic degradation, and versatile therapeutic potential. Their unique properties enable applications that extend beyond combating multidrug-resistant (MDR) pathogens. Their amphipathic and cell-penetrating properties allow them to efficiently transport drugs across cellular membranes.
AREAS COVERED: This review explores the structural advantages and mechanisms of action of CAMPs, emphasizing their role in drug delivery. The literature analysis (2010-2024) from PubMed, Scopus, and Web of Science highlights developments in CAMP-conjugated therapies, liposomal formulations, and encapsulation systems. The review also examines their antimicrobial potency, amphipathic and cell-penetrating properties, and integration into nanocarrier technologies to enhance drug stability, bioavailability, and precision targeting. Challenges such as toxicity, scalability, and cost are also discussed. CAMPs have the potential to revolutionize drug delivery through their robustness and multifunctionality, particularly in precision medicine.
EXPERT OPINION: Future advancements in peptide engineering, nanotechnology, and AI-driven design are expected to enhance CAMPs' therapeutic specificity, reduce toxicity, and broaden their applications, including oncology and gene therapy, paving the way for their integration into next-generation therapeutics.

Keywords:  Antimicrobial peptides; Peptide-drug conjugates; Self-assembling peptide vesicles; cellular uptake; cyclic antimicrobial peptides (CAMPs); cyclic peptide; drug delivery; liposomal nanocarriers

DOI:  https://doi.org/10.1080/17425247.2025.2460661
Indian J Endocrinol Metab. 2024 Nov-Dec;28(6):28(6): 601-610

Outcome of 177Lu-DOTATATE Peptide Receptor Radionuclide Therapy in Progressive Metastatic Neuroendocrine Tumors from a Tertiary Care Center.

David Mathew, Saumya S Sunny, Justin Benjamin, Junita R John, Felix K Jebasingh, Josh T Georgy, Ashish Singh, Regi Oommen.

   Introduction: Functioning neuroendocrine tumors (NETs) that do not respond to standard therapies are commonly considered for Peptide Receptor Radionuclide Therapy (PRRT). The benefit of 177Lu-DOTATATE PRRT in patients with progressive metastatic NET was analyzed and survival in multi-organ involvement.
Methods: Forty-one patients with refractory, progressive, or advanced symptomatic NETs, with or without previous treatment modalities were studied. They were treated with 177Lu-DOTATATE IV infusion 150 mCi per dose up to four cycles. Retrospectively, they were assessed for response to PRRT based on clinical, Imaging-Contrast CT/68Ga-DOTATATE PET-CT, and biochemical markers. After treatment, classification based on disease status, symptomatic improvement, and response to treatment based on Chromogranin A level was done. The organs involved and their respective survival benefits, as estimated by Kaplan Meier, were plotted for 60 months.
Results: The mean serum Chromogranin A level at baseline was 2841 U/ml (Median = 3150). The main site of primary NET was in the pancreas, and the most common site for metastases was the liver. Following PRRT, all patients, except one, reported an improvement in their baseline complaints. Most (82%) reported no new symptoms, and 50% had a reduction in serum Chromogranin A levels. Follow-up imaging showed regression in one patient, static tumor in 18, and progression in rest. Considering radiological and clinical responses, the overall benefit was noticed in 29 (70%) patients. Despite symptomatic improvement, there was no significant survival benefit for those with pancreatic, liver, or nodal metastasis.
Conclusion: A majority of patients who were treated with PRRT demonstrated clinical, radiological as well as biochemical positive responses warranting an earlier consideration for this well-tolerated treatment modality.

Keywords:  177Lu-dotatate; 68Ga-dotatate; Kaplan–Meier survival estimates; NET; PRRT; neuroendocrine tumor; peptide receptor radionuclide therapy

DOI:  https://doi.org/10.4103/ijem.ijem_372_23