bims-cepepe 2025-08-03 papers

bims-cepepe

Biomed News

on Cell-penetrating peptides

Issue of 2025–08–03
nineteen papers selected by
Henry Lamb, Queensland University of Technology

Direct Cellular Screening of Pd-Mediated Arylation of Cyclic Peptide Binders Targeting Ubiquitin Chains: Toward Modulating NEMO Liquid-Liquid Phase Separation.
A Beautiful Bind: Phage Display and the Search for Cell-Selective Peptides.
Membrane Repair Proteins as Negative Regulators of Cytosolic Delivery Using Attenuated Cationic Lytic Peptide L17E and Cell-Penetrating Peptides: Differences and Similarities.
The Assembly of Fluorescently Labeled Peptide-Oligonucleotide Conjugates.
Membrane-Embedded Anti-Cancer Peptide Causes a Minimal Structural Perturbation That Is Sufficient to Enhance Phospholipid Flip-Flop and Charge Permeation Rates.
Modular helix stabilization via alkenyl butylcarbamate staples: effects of staple length, stereochemistry, and directionality.
Tissue factor derived β-hairpin peptides that bind and inhibit FVII activity.
Macrocycles for Conventionally Druggable Targets: Lessons from Macrocyclic Kinase Inhibitors.
Improving Viral-based Gene Delivery to Mammalian Cells through Simple Co-Incubation with Transportan Peptide In Vitro.
Applying Unbiased, Functional Criteria Allows Selection of Novel Cyclic Peptides for Effective Targeted Drug Delivery to Malignant Prostate Cancer Cells.
Spectroelectrochemical analysis of membrane permeation mechanisms of cell-penetrating peptide-modified fluorescent proteins.
Recombinant Cell-Permeable Puromycin N-Acetyltransferase Confers Puromycin Resistance by Direct Protein Transduction.
A Unified Peptide Generative Framework via a Weakly Order-Dependent Autoregressive Language Model and Lifelong Learning.
Rationale Design of a Zn(II)-Coordinated, Cell Penetrating, and Functionalized Tetrapeptide Self-Assembly for Delivery of Chemotherapeutic Drugs to Folic Acid Receptor-Expressing Cancer Cells.
Novel Lung Cell-Penetrating Peptide Targets Alveolar Epithelial Type II Cells, Basal Cells, and Ionocytes.
A Short Peptide Inhibitor of Measles Virus Fusion Protein that Exhibits Passive Membrane Permeability.
Peptide-driven approaches in advanced wound healing materials.
A Peptide-Based PROTAC Degrader of BRCA2 Sensitizes Metastatic Castration-Resistant Prostate Cancer to PARP Inhibition.
Innovative Peptide Therapeutics in the Pipeline: Transforming Cancer Detection and Treatment.

J Am Chem Soc. 2025 Jul 28.

Direct Cellular Screening of Pd-Mediated Arylation of Cyclic Peptide Binders Targeting Ubiquitin Chains: Toward Modulating NEMO Liquid-Liquid Phase Separation.

Mahdi Hasan, Nagaraju Vodnala, Yuri Glagovsky, Yakop Saed, Julia Kriegesmann, Hiroaki Suga, Ashraf Brik.

Ubiquitination is a critical post-translational modification that regulates key cellular processes such as protein degradation and DNA damage repair. Targeting a specific type of ubiquitin chain (e.g., Lys48 or Lys63-linked ubiquitin chain) via cyclic peptides presents a new strategy to modulate biological processes with therapeutic potential for various diseases. However, such a strategy remains challenging due to the obstacles of cell permeability and bioactivity. Here, we present a new method that directly assesses these parameters by integrating palladium-mediated Cys arylation with direct cellular screening. Using CP4, a previously identified cyclic peptide modulator of Lys63-linked ubiquitin chains, we generated a focused library of arylated analogues and optimized the Pd-mediated arylation for direct cellular screening. We discovered a new analog, CP-P12-ArH, that demonstrated enhanced binding affinity and robust bioactivity, as evidenced by increased γ-H2AX phosphorylation and apoptosis induction in cancer cells. Furthermore, CP-P12-ArH effectively inhibited the in vitro formation of NF-κB essential modulator (NEMO) biomolecular condensates by disrupting the elongation of Lys63-linked ubiquitin chains, offering a novel way to modulate NF-κB signaling. This work establishes a generalizable platform for the rapid optimization of cyclic peptide therapeutics targeting protein-protein interactions.

DOI: https://doi.org/10.1021/jacs.5c09059
Viruses. 2025 Jul 12. pii: 975. [Epub ahead of print]17(7):

A Beautiful Bind: Phage Display and the Search for Cell-Selective Peptides.

Babak Bakhshinejad, Saeedeh Ghiasvand.

  Phage display has advanced the discovery of peptides that selectively bind to a wide variety of cell surface molecules, offering new modalities to modulate disease-related protein-protein interactions (PPIs). These cell-binding peptides occupy a unique pharmaceutical space between small molecules and large biologics, and their growing popularity has opened up new avenues for targeting cell surface proteins that were previously considered undruggable. This work provides an overview of methods for identifying cell-selective peptides using phage display combinatorial libraries, covering in vitro, ex vivo, and in vivo biopanning approaches. It addresses key considerations in library design, including the peptide conformation (linear vs. cyclic) and length, and highlights examples of clinically approved peptides developed through phage display. It also discusses the on-phage chemical cyclization of peptides to overcome the limitations of genetically encoded disulfide bridges and emphasizes advances in combining next-generation sequencing (NGS) with phage display to improve peptide selection and analysis workflows. Furthermore, due to the often suboptimal binding affinity of peptides identified in phage display selections, this article discusses affinity maturation techniques, including random mutagenesis and rational design through structure-activity relationship (SAR) studies to optimize initial peptide candidates. By integrating these developments, this review outlines practical strategies and future directions for harnessing phage display in targeting challenging cell surface proteins.

Keywords:  affinity maturation; biopanning; cell-selective ligands; combinatorial libraries; cyclic peptides; mutagenesis; next-generation sequencing; phage display; secondary libraries; sequence space

DOI:  https://doi.org/10.3390/v17070975
Bioconjug Chem. 2025 Jul 29.

Membrane Repair Proteins as Negative Regulators of Cytosolic Delivery Using Attenuated Cationic Lytic Peptide L17E and Cell-Penetrating Peptides: Differences and Similarities.

Masashi Kuriyama, Yoshimasa Kawaguchi, Shinji Ito, Junko Satoh, Hisaaki Hirose, Shiroh Futaki.

Cytosolic delivery of functional macromolecules is beneficial for intracellular targeting. Although numerous intracellular delivery methods have been developed, the biological factors that govern their efficacy remain poorly understood, thereby limiting further advancement of existing approaches. L17E is an attenuated cationic amphiphilic lytic (ACAL) peptide developed by our research group that facilitates the cytosolic delivery of macromolecules, including antibodies and functional proteins. The L17E peptide exhibits varying levels of cytosolic delivery even within a single cell line, suggesting heterogeneity in the cellular sensitivity to the delivery process. Based on the hypothesis that the specific proteins contribute to this variability, HeLa cells were sorted into L17E-sensitive and L17E-insensitive populations. Comparative proteome analysis of the membrane fractions of these two groups revealed that annexin A2, a membrane repair-related protein, was more abundant in L17E-insensitive cells. Time-lapse imaging and knockdown experiments indicated that annexin A2 negatively regulates L17E-mediated cytosolic delivery by sealing the plasma membrane regions permeabilized by the L17E peptide. To assess whether membrane repair factors also influence cytosolic delivery via conventional cell-penetrating peptides (CPPs), we examined the roles of repair-related proteins. We found that the endosomal sorting complex required for transport (ESCRT) suppressed the cytosolic translocation of the CPPs, whereas annexin A2 did not. These findings suggest that the L17E peptide and the CPPs utilize distinct membrane repair-associated pathways during delivery and that the expression levels of these repair factors affect delivery efficiency. Modulating such factors may therefore provide a strategy for enhancing peptide-based cytosolic delivery systems.

DOI: https://doi.org/10.1021/acs.bioconjchem.5c00177
Methods Mol Biol. 2025 ;2964 319-328

The Assembly of Fluorescently Labeled Peptide-Oligonucleotide Conjugates.

John A Karas, Bradley J Turner, Fazel Shabanpoor.

  Efficient intracellular delivery is critical to the successful application of synthetic antisense oligonucleotides (ASOs) to modulate gene expression. The conjugation of cell-penetrating peptides (CPPs) to ASOs has been shown to significantly improve their intracellular delivery. It is important, however, that formation of the covalent linkage between the peptide and oligonucleotide is efficient and orthogonal, to ensure high yields and a homogeneous product. Described herein are efficient and facile methodologies for the conjugation of CPPs to ASOs, and their subsequent labeling with various moieties such as fluorescent dyes for intracellular tracking studies.

Keywords:  Alkyne-azide; Conjugation; Fluorescent labeling; Oligonucleotides; Peptides; Thiol-maleimide

DOI:  https://doi.org/10.1007/978-1-0716-4730-1_21
Life (Basel). 2025 Jun 25. pii: 1007. [Epub ahead of print]15(7):

Membrane-Embedded Anti-Cancer Peptide Causes a Minimal Structural Perturbation That Is Sufficient to Enhance Phospholipid Flip-Flop and Charge Permeation Rates.

Alfredo E Cardenas, Ron Elber.

  A prime role of biological membranes is to form barriers for material transport into and out of cells. Membranes consist of phospholipids with polar heads, which are presented to the aqueous solutions, and hydrophobic tails that form the membrane core. This construct prevents the permeation of hydrophilic, well-solvated molecules across the lipid hydrophobic barrier. The barrier is not absolute, and several approaches are available for efficient translocation. Channels and pumps enable selective and efficient transport across membranes. Another transport mechanism is passive permeation, in which permeants, without assistance, directly transport across membranes. Passive transport is coupled to transient defects in the membrane structure that make crossing the hydrophobic bilayer easier-for example, displacements of head groups from aqueous solution-membrane interface into the membrane core. The defects, in turn, are rare unless assisted by passively permeating molecules such as cell-penetrating peptides that distort the membrane structure. One possible defect is a phospholipid molecule with a head pointing to the hydrophobic core. This membrane distortion allows head group flipping from one layer to the other. We show computationally, using atomically detailed simulations and the Milestoning theory, that the presence of a cell-penetrating peptide in a membrane greatly increases phospholipid flip-flop rate and hence defect formation and the permeability of membranes.

Keywords:  cell penetrating peptide; membrane defect; membrane permeation

DOI:  https://doi.org/10.3390/life15071007
Bioorg Med Chem. 2025 Jul 26. pii: S0968-0896(25)00275-5. [Epub ahead of print]129 118334

Modular helix stabilization via alkenyl butylcarbamate staples: effects of staple length, stereochemistry, and directionality.

Ha T N Nguyen, Thanh K Pham, Young-Woo Kim.

  Peptide stapling is a widely used approach for stabilizing α-helical peptides, improving their structural integrity, proteolytic resistance, and therapeutic potential. Here, we present a novel stapling strategy employing alkenyl butylcarbamate cross-links formed via ring-closing metathesis (RCM). This platform enables fine control over staple length, stereochemistry, and directionality. Through systematic analysis, the 13-atom hex-2-enyl butylcarbamate staple was identified as optimal, achieving enhanced α-helicity and efficient macrocyclization. We further demonstrate that peptide stereochemistry and staple orientation significantly impact both RCM efficiency and helix stabilization. Notably, the optimized stapled peptides exhibited a 45-fold increase in resistance to trypsin-mediated degradation compared to their unmodified counterparts. In addition, the carbamate linkage provided excellent resistance to non-enzymatic hydrolysis under physiological conditions. Together, these results highlight alkenyl butylcarbamate stapling as a chemically robust, hydrophilic, and conformationally rigid approach for stabilizing α-helical peptides. This strategy offers an attractive alternative to traditional hydrocarbon staples, particularly for therapeutic peptides targeting extracellular or membrane-bound proteins.

Keywords:  Butylcarbamate staple; Peptide stapling; Proteolytic stability; Ring-closing metathesis; α-Helix stabilization

DOI:  https://doi.org/10.1016/j.bmc.2025.118334
Eur J Med Chem. 2025 Jul 18. pii: S0223-5234(25)00752-4. [Epub ahead of print]298 117987

Tissue factor derived β-hairpin peptides that bind and inhibit FVII activity.

Angela Oliver, Emanuela Iaccarino, Arianna Migliorini, Samuele Di Cristofano, Lucia Falcigno, Gabriella D'Auria, Maria Cantile, Raffaele Ronca, Riccardo Sanna, Domenico Raimondo, Annamaria Sandomenico, Menotti Ruvo.

The formation of the Tissue Factor(TF):Factor VII(FVII) complex is a pivotal event that initiates coagulation; targeting this early step allows for the prevention of the subsequent cascade amplification driven by positive feedback loops. For this reason, the TF:FVII complex is attracting increasing interest as a potential therapeutic target for regulating the coagulation cascade in a specific and timely manner. In order to generate TF-mimics capable of inhibiting this protein-protein interaction, we have designed four small cyclic peptides that simulate a TF region containing the two antiparallel β-strands: 106-110 (RVFSY) and 123-128 (EPLYEN). These strands are known to interact with FVII at well-known hot spots surrounding residues 365-369. With the aim of obtaining structures as similar as possible to the corresponding region of TF and therefore able to interact better with FVII, the four combinations of proline-proline dipeptides resulting from the four permutations of D-Pro and L-Pro have been introduced between the two strands. These strands have been connected on the opposite side by a disulphide bond in order to stabilise the resulting structures and also make them more resistant to protease action. The two cyclopeptides with the D-Pro-L-Pro and D-Pro-D-Pro moieties adopt β-hairpin-like conformations that recapitulate the structure of the two strands, as demonstrated by CD, NMR and molecular simulation studies. They also bind FVII and inhibit its activity in a Factor X-generating chromogenic assay. The other two peptides are significantly more disordered and are inactive in the same tests. Overall, the data validate the peptide design and confirm the region 365-369 of FVII as a target site for the design of coagulation inhibitors.

DOI: https://doi.org/10.1016/j.ejmech.2025.117987
J Med Chem. 2025 Jul 31.

Macrocycles for Conventionally Druggable Targets: Lessons from Macrocyclic Kinase Inhibitors.

Lauren A Viarengo-Baker, Adrian Whitty.

Macrocycles are emerging as a prominent modality in drug discovery, including for conventionally druggable targets for which simpler, acyclic ligands are readily discoverable. Given the additional synthetic challenges associated with macrocyclic chemotypes, we address what benefits macrocycles provided for these highly druggable targets. To do this, we examine the effects of macrocyclization on inhibitors of highly druggable kinase targets. For each example, we isolate closely matched acyclic/macrocyclic compound pairs, allowing us to pinpoint the effects of macrocyclization on binding affinity, selectivity, and ADME properties absent confounding factors. Our findings show that while the impact of macrocyclization on potency is variable, a profound effect on selectivity is common. Macrocyclization can also bring benefits for membrane permeability, efflux ratio, blood-brain barrier penetrance, and metabolic stability. These findings lead us to propose specific circumstances in which a drug discoverer targeting kinases or other conventionally druggable target classes should consider a macrocycle approach.

DOI: https://doi.org/10.1021/acs.jmedchem.4c02886
J Pharm Sci. 2025 Jul 26. pii: S0022-3549(25)00372-7. [Epub ahead of print] 103920

Improving Viral-based Gene Delivery to Mammalian Cells through Simple Co-Incubation with Transportan Peptide In Vitro.

Nianwu Wang, Xiangxiang Hu, Hong-Bo Pang.

  Viral-based platforms, most notably lentivirus and adeno-associated virus (AAV), are widely used to deliver genetic materials into cells for various purposes. One of the challenges in their applications is poor cellular uptake efficiency, especially in difficult-to-transfect cell lines and primary cells. Current mainstream approaches to overcome this problem often require specialized instruments or cause unwanted damages to cell viability. As an alternative, we have developed technologies to improve cellular uptake of macromolecular payloads by simply mixing them with cell-penetrating peptides (co-administration). Our previous studies have shown that co-administration with Transportan (TP), a 27-amino-acid amphiphilic cell-penetrating peptide, could enhance the cellular uptake of nano-sized particles. Here, we set out to investigate whether TP has similar effect on viral-based gene delivery. Using GFP-expressing AAVs and lentivirus, we validated the ability of TP co-administration to increase their transfection in a number of cell lines with limited cytotoxicity. Then, we used one difficult-to-transfect cell lines and two primary cells: a macrophage cell line (Raw264.7), bone marrow-derived macrophages (BMDMs), and retinal pigment epithelium (RPE) cells. Similar effects were seen as well. Overall, we present here an easy approach to improve the efficiency of viral-based gene delivery and transfection, which may benefit various clinical applications.

Keywords:  Cell-penetrating peptides; Viral-based gene delivery

DOI:  https://doi.org/10.1016/j.xphs.2025.103920
Pharmaceutics. 2025 Jul 01. pii: 866. [Epub ahead of print]17(7):

Applying Unbiased, Functional Criteria Allows Selection of Novel Cyclic Peptides for Effective Targeted Drug Delivery to Malignant Prostate Cancer Cells.

Anna Cohen, Maysoon Kashkoosh, Vipin Sharma, Akash Panja, Sagi A Shpitzer, Shay Golan, Andrii Bazylevich, Gary Gellerman, Galia Luboshits, Michael A Firer.

  Background: Metastatic prostate cancer (mPrC), with a median survival of under 2 years, represents an important unmet medical need which may benefit from the development of more effective targeted drug delivery systems. Several cell surface receptors have been identified as candidates for targeted drug delivery to mPrC cells; however, these receptors were selected for their overabundance on PrC cells rather than for their suitability for targeted delivery and uptake of cytotoxic drug payloads. Methods: We describe a novel, unbiased strategy to isolate peptides that fulfill functional criteria required for effective intracellular drug delivery and the specific cytotoxicity of PrC cells without prior knowledge of the targeted receptor. Phage clones displaying 7-mer cyclic peptides were negatively selected in vivo and then positively biopanned through a series of parent and drug-resistant mPrC cells. Peptides from the internalized clones were then subjected to a panel of biochemical and functional tests that led to the selection of several peptide candidates. Results: The selected peptides do not bind PSMA. Peptide-drug conjugates (PDCs) incorporating one of the peptides selectively killed wild-type and drug-resistant PrC cell lines and patient PrC cells but not normal prostate tissue cells in vitro. The PDC also halted the growth of PC3 tumors in a xenograft model. Conclusions: Our study demonstrates that adding unbiased, functional criteria into drug carrier selection protocols can lead to the discovery of novel peptides with appropriate properties required for effective targeted drug delivery into target cancer cells.

Keywords:  peptide-drug conjugates; phage display; prostate cancer; targeted drug delivery

DOI:  https://doi.org/10.3390/pharmaceutics17070866
Bioelectrochemistry. 2025 Jul 21. pii: S1567-5394(25)00157-4. [Epub ahead of print]166 109054

Spectroelectrochemical analysis of membrane permeation mechanisms of cell-penetrating peptide-modified fluorescent proteins.

Hiroki Sakae, Kaho Takada, Chitose Maruyama, Yoshimitsu Hamano, Hirohisa Nagatani.

  Cell penetrating peptides (CPPs) can translocate substances into cells and have potential as molecular carriers in drug delivery system (DDS). In order to elucidate the cellular internalization mechanism of cargoes utilizing CPPs, the interfacial behavior of fluorescent protein, monomeric Azami-Green (mAG) modified with two types of CPPs, ε-poly-l-lysine (εPL) and octa-arginine (R8), was studied at the liquid|liquid interface as a model of biomembrane surfaces. CPP-unmodified mAG and R8-mAG showed the aqueous adsorption process at the water|1,2-dichloroethane interface. On the other hand, εPL-mAG was transferred across the interface accompanied by the adsorption steps at both sides of the interface. Spectroelectrochemical analysis indicated that the adsorption of mAG was facilitated at the phospholipid-modified biomimetic interface. In the presence of CPPs, the adsorption of mAG on the membrane surface was inhibited by competitive adsorption with εPL, whereas the phase transfer of mAG readily occurred due to the disturbance of the membrane structure by R8. Although the R8-mAG behaves in a similar membrane reaction mechanism to the unmodified mAG, the phase transfer efficiency of εPL-mAG was improved by suppressing the interaction with the phospholipid membrane. Therefore, the membrane permeation of mAG was successfully achieved by the modification with εPL. Present findings demonstrated that εPL is a promising CPP for the membrane permeation of proteins with a high hydrophilicity and molecular weight.

Keywords:  Biomimetic membrane surface; Cell-penetrating peptides (CPPs); ITIES; Monomeric Azami-green (mAG); Potential-modulated fluorescence spectroscopy (PMF); ε-Poly-l-lysine

DOI:  https://doi.org/10.1016/j.bioelechem.2025.109054
J Microbiol Biotechnol. 2025 Jul 18. 35 e2502049

Recombinant Cell-Permeable Puromycin N-Acetyltransferase Confers Puromycin Resistance by Direct Protein Transduction.

Jiwon Choi, Kyung-Hee Cho, Jiwon Im, Yeeun Seo, Amitesh Sharma, Kartic, Shivani Devi, Nattan Stalin, Seo Jin Park, Tae-Sik Park.

  Puromycin N-acetyltransferase (PAC) is an enzyme that catalyzes the acetylation of puromycin, an inhibitor of protein synthesis. The PAC gene is often co-transfected with genes of interest in the same vector to serve as a selective marker, conferring puromycin resistance to mammalian cells. Cell-penetrating peptides (CPPs), which are 5-30 amino acids in length, facilitate the translocation of functional cargoes across the cell membrane. Among these, the HIV-transactivator of transcription (TAT) sequence is widely applied for its cell-penetrating and protein-delivery capabilities. In this study, we investigated whether attachment of the TAT sequence to PAC (TAT-PAC) enables intracellular delivery of TAT-PAC protein into mammalian cells, thereby conferring puromycin resistance. A recombinant TAT-PAC protein was expressed in Escherichia coli and purified to homogeneity. The purified TAT-PAC protein retained enzymatic activity, with a specific activity of 197 nmol/min/mg. Intracellular delivery of TAT-PAC was confirmed using confocal microscopy and flow cytometry, employing an RFP (red fluorescent protein)-tagged TAT-PAC fusion protein. Treatment of HEK293 and SY5Y cells with TAT-PAC resulted in increased cell viability in the presence of puromycin, demonstrating its functionality as a selection marker. This study suggests the potential application of cell-permeable PAC protein for selection of co-delivered therapeutic or gene-editing proteins in mammalian cells, providing a promising alternative to traditional genetic selection methods.

Keywords:  Puromycin; antibiotics; cell penetrating peptide; puromycin N-acetyltransferase; transduction

DOI:  https://doi.org/10.4014/jmb.2502.02049
J Chem Inf Model. 2025 Aug 01.

A Unified Peptide Generative Framework via a Weakly Order-Dependent Autoregressive Language Model and Lifelong Learning.

Zhiwei Nie, Daixi Li, Yutian Liu, Fan Xu, Hongyu Zhang, Xiansong Huang, Xudong Liu, Zhennan Wang, Yiming Ma, Yuxin Ye, Feng Yin, Wen-Bin Zhang, Zhixiang Ren, Zhihong Liu, Zigang Li, Jie Chen.

Bioactive peptides have become strong candidates for a variety of clinical therapies due to their diverse advantages, which promote the development of deep generative models for peptide generation. Considering that existing methods cannot effectively deal with the conformational flexibility of peptides and find it difficult to capture accurate residue-to-residue interaction dependencies, we propose a unified peptide generative framework, PepGenWL, via a weakly order-dependent autoregressive language model and lifelong learning. PepGenWL introduces tolerance for out-of-order input as an inductive bias into the autoregressive language model, coupled with Mixture-of-Experts-style plugins to maintain the optimal trade-off between memory stability and learning plasticity across multiple rounds of fine-tuning. The superiority of PepGenWL was demonstrated by generating three classes of therapeutic peptides, including antimicrobial peptides, anticancer peptides, and peptide binders. Under performance evaluation on raw and permuted peptide sequences, PepGenWL not only surpassed state-of-the-art baseline models across the board but also exhibited a significant propensity to incorporate specific residues that are beneficial for antimicrobial or anticancer bioactivity. Furthermore, the property-guided peptide binder generation, screening, and in vitro experimental validation pipeline was presented, achieving a target binding rate of 28.6% with binding specificity. More importantly, the applicability of PepGenWL can be broadened to encompass the peptide SMILES chemical space, thereby facilitating the generation of chemically modified peptides as well as cyclic peptides. Overall, PepGenWL is a unified framework for general-purpose peptide generation that can be flexibly customized for different task requirements.

DOI: https://doi.org/10.1021/acs.jcim.5c00623
ACS Appl Bio Mater. 2025 Jul 30.

Rationale Design of a Zn(II)-Coordinated, Cell Penetrating, and Functionalized Tetrapeptide Self-Assembly for Delivery of Chemotherapeutic Drugs to Folic Acid Receptor-Expressing Cancer Cells.

Nanjundan Raghul, Anushree Lye, Bhagwat Giri Goswami, Suman Nayak, Adele Stewart, Rabindranath Lo, Biswanath Maity, Priyadip Das.

  Design and development of functionalized and biocompatible drug delivery systems (DDS) for site-specific release of small molecules is emerging as a means to target disease sites while sparing healthy tissue. Cell penetrating short peptides capable of self-assembly and drug encapsulation represent one scaffold with which selective DDSs can be rationally designed due to their chemical diversity, biocompatibility, tunable bioactivity, ease of functionality, and high loading capacity. Herein, we designed and synthesized two tetra peptides, BOC-YWWD (PB1 with Trp-Trp-Sequence) and BOC-WYWD (PB2 without Trp-Trp sequence). Structural rigidification of these two peptides with Zn(II) in the self-assembled state were characterized by the density functional theory (DFT) method and demonstrated to shift self-assembly of their characteristic emission from the ultraviolet to visible range allowing for visualization of cellular entry. PB1-Zn, unlike PB2-Zn, exhibits cell penetrating capabilities and is photo and thermally stable and biocompatible. Self-assembled PB1-Zn effectively encapsulated the chemotherapeutic drug Doxorubicin (Dox) and facilitated intracellular drug delivery. To test the utility of PB1-Zn as a DDS, we chemically modified PB1-Zn with folic acid to target folate receptor α (FLOR1), commonly overexpressed on the surface of cancer cells. In HeLa cervical cancer cells, this chemical conjugation with folic acid significantly improved the ability of Dox to activate the pro-apoptotic DNA damage response and trigger oxidative stress and mitochondrial dysfunction critical for the cancer cell killing actions of the drug. However, PB1-Zn failed to facilitate Dox delivery into the lung cancer epithelial cell line, A549, which does not express high levels of FLOR1. Our results represent an important proof of concept describing the fabrication of fluorescent Zn(II) coordinated, self-assembled short peptides containing the sequential Trp-Trp unit that may be used to develop superior imaging reagents and site-specific DDSs.

Keywords:  Apoptosis; Cell penetrating peptide; Cellular imaging; Folate receptor; Site-specific drug delivery

DOI:  https://doi.org/10.1021/acsabm.5c00965
Pharmaceutics. 2025 Jun 25. pii: 824. [Epub ahead of print]17(7):

Novel Lung Cell-Penetrating Peptide Targets Alveolar Epithelial Type II Cells, Basal Cells, and Ionocytes.

Jin Wen, Gajalakshmi Singuru, Jeffrey Stiltner, Sanjay Mishra, Kyle S Feldman, Kayla McCandless, Raymond Yurko, Kazi Islam, Ray Frizzell, Hisato Yagi, Jonathan M Brown, Maliha Zahid.

  Background: Cell-penetrating peptides cross cell membrane barriers while carrying cargoes in a functional form. Our work identified two novel lung-targeting peptides, S7A and R11A. Here, we present studies on biodistribution, the cell types targeted, and an in vitro proof of application. Methods: Studies were performed in human bronchial epithelial cells (HBECs) with and without various endocytic inhibitors, and coincubation with fluorescently labeled transferrin or endocytic markers. Cyclic R11A (cR11A) was conjugated to siRNA duplexes and anti-viral activity against SARS-CoV-2 was tested. Biodistribution studies were performed by injecting wild-type mice with fluorescently labeled peptides, and various circulation times were allowed for, as well as cross-staining of lung sections or isolated single cells with various cellular markers, followed by fluorescence-activated cell sorting or confocal microscopy. Results: cR11A showed peak uptake in 15 min, with the highest uptake in airway epithelial type II (ATII) cells, followed by p63+ basal cells and ionocytes. Cyclization increased transduction efficiencies ~100-fold. Endocytosis studies showed a decrease in peptide uptake by pre-treatment with Pitstop2 but not Amiloride or Nystatin. Endocytic marker Lamp1 showed colocalization at the earliest time point, with the escape of the peptide from endocytic vesicles later. cR11A conjugated to ant-spike and anti-envelop proteins showed anti-viral effects with an EC90 of 0.6 μM and 1.0 µM, respectively. Conclusions: We have identified a novel peptide, cR11A, that targets ATII, basal cells, and ionocytes, the cyclization of which increased transduction efficiency in vitro and in vivo. The uptake mechanism appears to be via clathrin-mediated endocytosis with escape from endocytic vesicles. cR11A can act as a vector to deliver anti-viral siRNA to epithelial cells.

Keywords:  alveolar type II cells; basal cells; cell-penetrating peptides; ionocytes; siRNA

DOI:  https://doi.org/10.3390/pharmaceutics17070824
ChemMedChem. 2025 Jul 28. e202500532

A Short Peptide Inhibitor of Measles Virus Fusion Protein that Exhibits Passive Membrane Permeability.

Ziwei Gao, Jiei Sasaki, Tateki Suzuki, Shinsuke Sando, Takao Hashiguchi, Jumpei Morimoto.

  In this study, a passively membrane-permeable short peptide inhibitor targeting the measles virus fusion protein (MeV-F) is reported. Measles virus (MeV) is highly contagious, yet no approved antiviral drugs are currently available. MeV-F plays a crucial role in viral infection, making it an attractive target for drug development. The fusion inhibitor peptide (FIP) is a well-known short peptide that binds to MeV-F and prevents its structural rearrangement. However, improving both inhibitory activity and passive membrane permeability is essential for developing orally available MeV-F inhibitors. Herein, FIP derivatives are explored through hydrogen-to-fluorine substitution and a derivative with enhanced inhibitory activity (IC50 = 90 nM) and passive membrane permeability (Pe = 1.4 × 10-6 cm s-1) was identified. This study highlights the potential of the long-studied fusion inhibitor peptide as a promising lead compound for the development of orally available drugs against measles infection.

Keywords:  fluorination; fusion inhibitor peptides; measles virus; membrane permeability

DOI:  https://doi.org/10.1002/cmdc.202500532
Drug Discov Today. 2025 Jul 30. pii: S1359-6446(25)00153-9. [Epub ahead of print] 104440

Peptide-driven approaches in advanced wound healing materials.

Zhang Chen, Lei Meng, Gautam Sethi, Jinxiang Wang, Baisen Li.

  Peptide-based materials such as antimicrobial peptides (AMPs), cell-penetrating peptides (CPPs), angiogenic peptides, and extracellular matrix (ECM)-mimetic peptides offer unique multifunctional benefits for wound healing, including infection control, enhanced angiogenesis, immunomodulation, and tissue regeneration. Representative platforms, including hydrogels, nanofibers, functionalized dressings, and delivery systems, leverage these peptides for sustained therapeutic action and improved healing outcomes. Despite promising advances, significant translational barriers remain, including peptide stability, enzymatic degradation, manufacturing scalability, and regulatory approval. Addressing these barriers through optimized peptide engineering and delivery strategies is essential for clinical translation and wider clinical adoption of peptide-driven wound therapies.

Keywords:  antimicrobial peptides; bioactive hydrogels; peptide-based materials; tissue regeneration; wound healing

DOI:  https://doi.org/10.1016/j.drudis.2025.104440
Cancer Res. 2025 Jul 29.

A Peptide-Based PROTAC Degrader of BRCA2 Sensitizes Metastatic Castration-Resistant Prostate Cancer to PARP Inhibition.

Qi Ye, Bohan Ma, Lei Li, Zixi Wang, Mingming Lu, Jialu Kang, Yuzeshi Lei, Shan Xu, Ke Wang, Yanlin Jian, Yizeng Fan, Bin Wang, Jing Liu, Yang Gao, Jian Ma, Lei Li.

Defects in homologous recombination repair (HR) make cells highly susceptible to PARP inhibitors. However, the limited efficacy of PARP inhibitors in targeting HR wild-type tumors restricts their broad utility in cancer treatment. Clinical trials of PARP inhibitors have revealed greater efficacy in men with metastatic castration-resistant prostate cancer (mCRPC) harboring BRCA2 mutations compared to those with mutations in other HR genes. To address this, we developed a peptide-based proteolysis-targeting chimera (PROTAC) drug that specifically targets BRCA2, leading to its degradation in a DDB1-dependent manner. The interaction between DDB1 and BRCA2 facilitated nuclear accumulation of the BRCA2 peptide PROTAC (BPD), thereby promoting BRCA2 degradation in response to DNA damage. Combining BPD treatment with PARP inhibitors promoted cell death in prostate cancer cells and induced tumor regression in animal models. These findings suggest that development of a PROTAC drug targeting BRCA2 offers a promising strategy in combination with PARP inhibitor therapy for treating cancers without HR defects. This approach holds potential for expanding the therapeutic application of PARP inhibition for prostate cancer management.

DOI: https://doi.org/10.1158/0008-5472.CAN-24-4096
Int J Mol Sci. 2025 Jul 16. pii: 6815. [Epub ahead of print]26(14):

Innovative Peptide Therapeutics in the Pipeline: Transforming Cancer Detection and Treatment.

Yanyamba Nsereko, Amy Armstrong, Fleur Coburn, Othman Al Musaimi.

  Cancer remains a leading global health burden, profoundly affecting patient survival and quality of life. Current treatments-including chemotherapy, radiotherapy, immunotherapy, and surgery-are often limited by toxicity or insufficient specificity. Conventional chemotherapy, for instance, indiscriminately attacks rapidly dividing cells, causing severe side effects. In contrast, peptide-based therapeutics offer a paradigm shift, combining high tumour-targeting precision with minimal off-target effects. Their low immunogenicity, multi-pathway modulation capabilities, and adaptability for diagnostics and therapy make them ideal candidates for advancing oncology care. Innovative peptide platforms now enable three transformative applications: (1) precision molecular diagnostics (e.g., 18F-PSMA-1007 for prostate cancer detection), (2) targeted therapies (e.g., BT5528 and SAR408701 targeting tumour-specific antigens), and (3) theranostic systems (e.g., RAYZ-8009 and 177Lu-FAP-2286 integrating imaging and radiotherapy). Despite their promise, peptides face challenges like metabolic instability and short half-lives. Recent advances in structural engineering (e.g., cyclization and D-amino acid incorporation) and delivery systems (e.g., nanoparticles and PEGylation) have significantly enhanced their clinical potential. This review highlights peptide-based agents in development, showcasing their ability to improve early cancer detection, reduce metastasis, and enhance therapeutic efficacy with fewer adverse effects. Examples like CLP002 underscore their role in personalised medicine. By overcoming current limitations, peptide drugs are poised to redefine cancer management, offering safer, more effective alternatives to conventional therapies. Their integration into clinical practice could mark a critical milestone in achieving precision oncology.

Keywords:  cancer; diagnostic; peptides; targeted therapy; theranostic

DOI:  https://doi.org/10.3390/ijms26146815