Search Results (1,086)

The current known data on the involvement of the peptidergic systems in breast cancer progression is overwhelmingly vast. Peptidergic systems are useful tools for imaging, diagnosis, prognosis and treatment of breast cancer. These systems play a crucial role in both basic and clinical breast cancer research by enabling the exploration of novel molecular mechanisms, signaling pathways, and the development of effective drug design strategies. Breast cancer cells overexpress peptide receptors; at the same time they are known to interact with peptides that (a) exert an oncogenic action (adrenomedullin 2, endothelin, gastrin-releasing peptide, neurokinin A, neuromedin, neuropeptide Y, neurotensin, substance P, vasoactive intestinal peptide), (b) exert an anticancer action (angiotensin (1–7), ghrelin, peptide YY) or (c) exert dual oncogenic and anticancer effects (adrenomedullin, angiotensin II, bradykinin, corticotropin-releasing factor, β-endorphin, glucagon-like peptide 1, gonadotropin-releasing hormone, kisspeptin, methionine-enkephalin, oxytocin). This indicates that peptides, as well as peptide receptor agonists and antagonists, may serve as antitumor agents due to their diverse actions against breast cancer development, including the inhibition of cell proliferation, migration and invasion, induction of apoptosis, and anti-angiogenesis. Multiple strategies have been developed to combat breast cancer, including peptide receptor silencing; antibodies conjugated to specific signaling proteins; antibodies targeting specific peptide receptors or oncogenic peptides; and the use of peptides or peptide receptor agonists/antagonists loaded with antitumor cargo. Future lines of research are suggested in breast cancer using promising anti-breast-cancer peptide receptor antagonists (HOE-140, exendin (9–39), bosentan, macitentan, PD168,368, CGP71,683A, SR48,692, aprepitant) or agonists (FR190,997, semaglutide, exendin 4, goserelin) mentioned in this review. Peptidergic systems have tremendous anti-breast-cancer clinical potential which must be exploited and developed. Taken together, the available data highlight the enormous promise of translational research into breast cancer and peptidergic systems for the development of effective treatments. A full understanding of the roles played by the peptidergic systems in breast cancer will serve to improve diagnosis and treatment. Full article

Peptides are emerging as versatile platforms in medicine, serving as therapeutic agents, diagnostic probes, and drug delivery vehicles. Their physical state—in a form of monomeric cell-penetrating peptides (CPPs), liquid-like coacervates, or solid amyloid fibrils—critically determines their interaction with cell surfaces and subsequent intracellular trafficking pathways. While the transport of CPPs has been extensively studied, the mechanisms governing the cellular uptake of peptide-based coacervates and fibrils are less understood. This review summarizes the current understanding of the intracellular transport mechanisms of all three distinct peptide states and their complexes or conjugates with cargo molecules. We examine a range of pathways, including direct membrane translocation, several endocytosis subtypes, and phagocytosis-like transport. Particular attention is given to unique aspects observed exclusively for CPPs, coacervates, or fibrils. Further verification and detailed characterization of internalization mechanisms are crucial for the rational design of next-generation peptide-based carriers that allow for precise cargo delivery and therapeutic efficacy. Full article

Chronic inflammation constitutes a significant characteristic of sustained infections caused by viral and fungal pathogens, with a strong correlation to the development of cancer, autoimmune disorders, and tissue fibrosis. Viral proteins such as HIV-1 Tat, HBV X (HBx), HPV E6/E7, and EBV LMP1 modulate the host’s immune signaling pathways, primarily through the activation of the NF-κB signaling cascade and the disruption of cytokine equilibrium. These molecular interactions result in a pro-inflammatory microenvironment that facilitates viral persistence, immune evasion, and the process of oncogenesis. Structural investigations have elucidated the mechanisms by which these viral proteins interact with host signaling complexes, thereby highlighting their potential as viable therapeutic targets. Similarly, fungal proteins, including secreted aspartyl proteases (Saps), ribotoxin Asp f1, and chitin-binding proteins, incite chronic inflammation by activating pattern recognition receptors and triggering inflammasome activation. Despite the limited structural information of these fungal proteins, emerging models and bioinformatic analyses identified conserved motifs that are crucial for host interactions. Biologic therapies, encompassing antiviral and antifungal peptides as well as monoclonal antibodies, are currently under development to disrupt these protein-host interactions and modulate inflammatory responses. This review provides structural and functional insight into viral and fungal inflammatory proteins and evaluates the potential of biologics as targeted therapeutic interventions for chronic inflammation associated with infections. We discuss the ongoing clinical trials involving neutralizing antibodies targeting HIV, peptide vaccines aimed at HPV and other promising molecules. Finally, we discuss the current limitations of biologics and possible solutions to translate these promising therapeutics into clinical practice. Full article

Liposomes modified with slightly acidic pH-sensitive peptides (SAPSp-lipo) are effectively delivered to tumor tissues, followed by cellular uptake in the tumor microenvironment. Although SAPSp-lipo can penetrate tumor tissues via the interspace route between cancer cells and the extracellular matrix (ECM), penetration needs to be enhanced to deliver liposomes into tumor cores comprising malignant cancer cells. To enhance the intratumoral penetration of SAPSp-lipo, we focused on the internalizing RGD peptide (iRGD), which can penetrate tumor tissue, differing from the penetration mechanism of SAPSp. In this study, we developed liposomes modified with iRGD-conjugated SAPSp (SAPSp-iRGD-lipo). Compared with SAPSp-lipo, SAPSp-iRGD-lipo was delivered to deeper regions within both spheroids and tumor tissues. The enhanced penetration was suppressed by a co-treatment with a Neuropilin-1 inhibitor, and the fluorescence signals from intratumorally injected SAPSp-iRGD-lipo were localized in Neuropilin-1-expressing regions, indicating a Neuropilin-1-mediated tumor penetration. Moreover, SAPSp-iRGD-lipo reduced F-actin formation in monolayered cells and was not localized in F-actin-rich regions in tumors, suggesting that SAPSp-iRGD-lipo facilitates tumor penetration through actin depolymerization. In addition, anticancer siRNA delivered by SAPSp-iRGD-lipid nanoparticles effectively induced apoptosis in cells under slightly acidic conditions. Taken together, SAPSp-iRGD-modified nanoparticles represent a novel class of tumor-penetrable and microenvironment-responsive drug carriers capable of efficient intratumoral delivery and therapeutic activity. Full article

Non-small cell lung cancer (NSCLC) remains a leading cause of cancer mortality, with therapeutic resistance posing the primary barrier to durable outcomes. Beyond genetic and epigenetic alterations, amino acid transporter-driven metabolic reprogramming—mediated by LAT1 (SLC7A5), ASCT2 (SLC1A5), and xCT (SLC7A11)—supports tumor proliferation, redox homeostasis, and immune escape. Their preferential expression in NSCLC highlights their potential as therapeutic targets and predictive biomarkers. In parallel, α-particle therapy has gained attention for its capacity to eradicate resistant clones through densely clustered, irreparable DNA double-strand breaks. Astatine-211 (²¹¹At) combines a clinically relevant half-life, high linear energy transfer, and predictable decay scheme, positioning it as a unique candidate among α-emitters. Preclinical studies of ²¹¹At-labeled transporter ligands, particularly LAT1-targeted conjugates, demonstrate potent tumor suppression and synergy with targeted therapy, chemotherapy, radiotherapy, immunotherapy, and ferroptosis inducers. Advances in radiochemistry, delivery systems (antibodies, peptides, and nanocarriers), and PET tracers such as [¹⁸F]FAMT and [¹⁸F]FSPG collectively support a theranostic framework for patient stratification and adaptive dosing. By linking transporter biology with α-particle delivery, ²¹¹At-based theranostics offer a mechanistically orthogonal strategy to overcome resistance and heterogeneity in NSCLC. Successful translation will depend on precise dosimetry, scaffold stabilization, and biomarker-guided trial design, enabling progression toward first-in-human studies and future integration into multimodal NSCLC therapy. Full article

Poly(lactic-co-glycolic acid) (PLGA) sustained-release systems for intra-articular (IA) delivery aim to extend joint residence time and reduce the reinjection frequency of conventional IA therapies. This review synthesizes current understanding of PLGA degradation, the acidic microenvironment inside degrading microspheres, and release behavior in joints, and surveys clinical experience with extended-release corticosteroid depots alongside emerging platforms for nonsteroidal and biologic agents. To situate PLGA within the broader IA field, we briefly summarize selected non-PLGA sustained-release approaches—such as multivesicular liposomes, hyaluronic acid conjugates, and hybrid matrices—to contextualize comparative performance and safety. For proteins and peptides, central barriers include acidification inside degrading microspheres, aggregation during fabrication and storage, and incomplete or delayed release, as illustrated by glucagon-like peptide-1 analog formulations. Mitigation strategies span pH buffering, excipient-based stabilization, and gentler manufacturing that improve encapsulation efficiency and preserve bioactivity. Translation hinges on manufacturing scale-up and quality systems that maintain critical particle attributes and enable informative in vitro–in vivo interpretation. Clinically, prolonged symptom relief after single dosing has been demonstrated for corticosteroid depots (e.g., ~50% pain reduction over 12 weeks with a single PLGA–triamcinolone injection), whereas repeat-dose safety and indication expansion beyond the knee remain active needs best addressed through multicenter trials incorporating imaging and patient-reported outcomes. Consistent real-world performance will depend on controlling batch-to-batch variability and implementing pharmacovigilance approaches suited to long dosing intervals, enabling broader clinical adoption. Full article

Infectious hematopoietic necrosis virus (IHNV), a salmonid rhabdovirus, causes severe mortality exceeding 90% in both wild and farmed salmon and trout. Frequent outbreaks of IHNV highlight the urgent need for rapid detection methods to support effective prevention and control. This study developed a double-antibody sandwich ELISA (DAS-ELISA) targeting the nucleocapsid (N) protein of IHNV. Two peptides derived from the N protein—selected for their strong antigenicity, high level of conservation, and surface accessibility—were used as immunogens to generate two specific monoclonal antibodies. Following optimization, the DAS-ELISA was established using monoclonal antibody N-15 as the capture antibody and horseradish peroxidase (HRP)-conjugated antibody N-106 as the detection antibody. The results of this study demonstrated that DAS-ELISA exhibited high specificity for multiple IHNV strains and showed no cross-reactivity with IPNV, SVCV, or VHSV. The detection sensitivity of DAS-ELISA for IHNV was determined to be 10³ TCID₅₀/mL. Parallel analysis of 293 clinical samples using DAS-ELISA and WOAH reference method demonstrated a concordance rate of 92.83% (κ = 0.856). These results confirm that the established DAS-ELISA exhibits high sensitivity, specificity, broad-spectrum applicability, and repeatability. In conclusion, this DAS-ELISA provides a reliable and efficient tool for high-throughput early detection of IHNV infection in clinical settings. Full article

Background/Objective: The rise in bacterial resistance necessitates novel therapeutic strategies beyond conventional antibiotics. Antimicrobial peptides represent promising candidates but face challenges such as instability, enzymatic degradation, and host toxicity. To overcome these limitations, conjugation and structural modifications are being explored. This study focuses on designing peptide-based inhibitors of the quorum-sensing (QS) regulator LasR in Pseudomonas aeruginosa, a key mediator of biofilm formation and antibiotic resistance. Methods: Rationally designed tripeptides and dipeptides conjugated with coumarin-3-carboxylic acid and dihydro-3-amino-2-(3H)-furanone were evaluated using molecular docking. The most promising ligand–protein complexes were further analyzed using molecular dynamics (MD) simulations conducted with the CHARMM-GUI and AMBER tools to assess the stability of the ligand–protein complex systems, and the binding affinities were evaluated using Molecular Mechanics–Poisson Boltzmann Surface Area (MM-PBSA) calculations. Pharmacokinetic and toxicity profiles were predicted using ADMETLab 3.0. Selected compounds were synthesized via solid-phase peptide synthesis, structurally confirmed by ¹H NMR and ESI-MS, and tested for antibacterial and antibiofilm activity against P. aeruginosa ATCC 27853. Results: Computational analyses identified several promising inhibitors with stronger binding affinities than the native autoinducer OdDHL. Coumarin conjugates C004 and C006 showed superior docking scores, while MM-PBSA indicated P004 and C004 had the most favorable binding energies. MD simulations confirmed stable ligand–protein complexes. ADMET predictions highlighted C004 and C006 as having excellent pharmacokinetic properties. Experimental assays showed moderate antibacterial activity (MIC 512–1024 µg/mL) and strong antibiofilm inhibition, particularly for C004 (83% inhibition at ½ MIC). Conclusions: The study demonstrates that peptide–coumarin conjugates, especially C004, are promising tools for disrupting QS and biofilm formation in P. aeruginosa. Further optimization and in vivo validation are needed to advance these compounds toward therapeutic application. Full article

The blood–brain barrier (BBB) restricts the entry of therapeutic agents into the brain cardiovascular regulatory region, potentially contributing to drug-resistant hypertension. Objective: The objective of this study was to overcome this limitation by modifying PEGylated liposomes with transferrin (Tf) to facilitate Tf receptor binding at the BBB and penetratin (Pen), a cell-penetrating peptide, to enhance neuronal uptake. Methods: This study evaluated the efficacy of Tf-Pen-liposomes in delivering angiotensin-converting enzyme 2 (ACE2) or EGFP (control) genes across the BBB in rats. In addition, the therapeutic effect of intravenous administration of Tf-Pen-Lip carrying plasmid DNA encoding ACE2 (Tf-Pen-Lip-pACE2) was tested in a neurogenic hypertension model induced by intracerebroventricular (ICV) infusion of angiotensin II (Ang II) via osmotic pump implantation and brain cannulation. Results: Conjugation with Tf and Pen significantly enhanced liposome-mediated gene transfection in cultured cells and increased transport across an in vitro BBB model. In vivo, intravenous administration of Tf-Pen-Lip-pACE2 or Tf-Pen-Lip-pGFP successfully elevated ACE2 or EGFP expression, respectively, in the hypothalamic paraventricular nucleus (PVN). Chronic ICV infusion of Ang II produced a sustained increase in blood pressure and heart rate, accompanied by sympathetic overactivation and elevated arginine vasopressin (AVP) secretion, hallmarks of neurogenic hypertension. Notably, intravenous Tf-Pen-Lip-pACE2 treatment dramatically attenuated Ang II–induced neurogenic hypertension, whereas Tf-Pen-Lip-pGFP had no effect on pressor responses, sympathetic activity, or AVP secretion. Conclusions: This dual-functionalized liposomal delivery system effectively transported the ACE2 gene across the BBB into the brain, increased ACE2 expression, and markedly attenuated neurogenic hypertension following systemic administration. Full article

Herpes simplex virus type 1 (HSV-1) is a leading cause of infectious corneal blindness worldwide. Human donor corneal transplantation remains the primary treatment for scarred corneas resulting from herpes simplex keratitis (HSK), a severe inflammatory corneal disease caused by HSV-1 infection, despite a high risk of re-infection or immune rejection of the allografts. As possible alternatives to donor grafting for HSK, we developed cell-free, regeneration-stimulating corneal implants designed to work even under adverse inflammatory situations such as severe infections. The implants comprised short, fully synthetic collagen-like peptides conjugated to polyethylene glycol (CLP-PEG) and crosslinked using carbodiimide chemistry. Being cell-free, they lacked the cellular targets that an already activated immune system would encounter in these inflamed corneas. We tested the performance of these implants in guinea pig and rabbit models of HSK. Three different HSV-1 strains were used to create experimental HSK in rabbits and guinea pigs. There were no overall statistically significant species differences or species–strain differences in virus-induced mortality. At three months post-operation, all treated corneas showed tissue regeneration, but with haze or neovascularization. The initially cell-free CLP-PEG implants allowed for repopulation by ingrowing cells to regenerate neocorneal tissue, despite the inflammation. However, they did not prevent HSV-1 reactivation nor re-infection, as neovascularization and disorganization were observed within the neocorneas. A detailed histopathological examination revealed viral strain differences, but only KOS infection showed interspecies neovascularization differences. A more detailed examination with larger numbers of animals is merited to fully elucidate the effects of the different viral strains on rabbits versus guinea pigs. Full article

Background/Objectives: Glioblastoma (GBM) is an aggressive primary brain tumor with limited therapeutic options despite multimodal treatment. Small interfering RNA (siRNA)-based therapeutics can silence tumor-promoting genes, but achieving efficient and tumor-specific delivery remains challenging. Lipid nanoparticles (LNPs) are promising siRNA carriers; however, conventional antibody conjugation can impair antigen recognition and complicate manufacturing. This study aimed to establish a modular Fc-binding peptide (FcBP)-mediated post-insertion strategy to enable PD-L1-targeted delivery of VEGF-siRNA via LNPs for GBM therapy. Methods: Preformed VEGF-siRNA-loaded LNPs were functionalized with FcBP–lipid conjugates, enabling non-covalent anchoring of anti-PD-L1 antibodies through Fc interactions. Particle characteristics were analyzed using dynamic light scattering and encapsulation efficiency assays. Targeted cellular uptake and VEGF gene silencing were evaluated in PD-L1-positive GL261 glioma cells. Anti-tumor efficacy was assessed in a subcutaneous GL261 tumor model following repeated intratumoral administration using tumor volume and bioluminescence imaging as endpoints. Results: FcBP post-insertion preserved LNP particle size (125.2 ± 1.3 nm), polydispersity, zeta potential, and siRNA encapsulation efficiency. Anti-PD-L1–FcBP-LNPs significantly enhanced cellular uptake (by ~50-fold) and VEGF silencing in PD-L1-expressing GL261 cells compared to controls. In vivo, targeted LNPs reduced tumor volume by 65% and markedly suppressed bioluminescence signals without inducing weight loss. Final tumor weight was reduced by 63% in the anti-PD-L1–FcBP–LNP group (656.9 ± 125.4 mg) compared to the VEGF-siRNA LNP group (1794.1 ± 103.7 mg). The FcBP-modified LNPs maintained antibody orientation and binding activity, enabling rapid functionalization with targeting antibodies. Conclusions: The FcBP-mediated post-insertion strategy enables site-specific, modular antibody functionalization of LNPs without compromising physicochemical integrity or antibody recognition. PD-L1-targeted VEGF-siRNA delivery demonstrated potent, selective anti-tumor effects in GBM murine models. This platform offers a versatile approach for targeted nucleic acid therapeutics and holds translational potential for treating GBM. Full article

Acinetobacter baumannii is an opportunistic pathogen associated with severe bloodstream infections. It exhibits a high level of multidrug resistance, posing major clinical challenges. Antisense peptide nucleic acids (PNAs) represent a promising alternative to conventional antibiotics; however, their therapeutic efficacy depends on optimal delivery and molecular design. In this study, we aimed to enhance the antibacterial activity of PNAs against A. baumannii by systematically optimizing cell-penetrating peptides (CPPs), PNA length, target region, and chemical modifications. The efficacy and safety of CPP–PNA constructs were evaluated using a comprehensive set of approaches, including determination of minimum bactericidal and minimum inhibitory concentrations, quantitative reverse transcription polymerase chain reaction, Western blotting, and cytotoxicity assays. Three CPP–PNA constructs targeting carA were synthesized. Among these, the KFFK (FFK)₂–PNA conjugate showed the strongest bacterial growth-inhibitory effect, while the addition of extra lysine residues reduced its efficacy. Further analyses showed that a 10-mer alpha (α)-PNA modification targeting the ribosomal binding site of carA had the greatest inhibitory effect. These results underscore the importance of rational CPP design and PNA optimization in developing effective antisense antimicrobials against A. baumannii. Full article

In this study, nanoparticles prepared by the heat-induced self-assembly of bovine serum albumin-dextran conjugates (BSA-DX) were utilized as an effective delivery system for the immunoregulatory peptide Gln-Leu-Asn-Trp-Asp (QLNWD) from Meretrix meretrix. The effects of dry-heating duration on the fabrication and characteristics of glycoprotein nanoparticles (GBA NPs) were investigated. Stable GBA NPs (110.84 nm) were obtained after 9 h of dry-heating. Depending on the addition sequence of QLNWD, the QLNWD-loaded nanoparticles were categorized into two types: pre-loading and post-loading. The two strategies were evaluated based on physicochemical characterization, colloidal stability, and RAW264.7 macrophage uptake. Results showed that upon QLNWD incorporation, both pre-loading NPs and post-loading NPs exhibited spherical morphology, with particle sizes decreasing to 105.51 nm and 94.27 nm, respectively. The encapsulation efficiency of pre-loading NPs for QLNWD was higher (87.74%), and the co-localization ability between post-loading NPs and QLNWD was stronger (Pearson’s correlation coefficient = 0.95). In vitro simulated gastrointestinal digestion experiments showed that QLNWD bioaccessibility increased to 47.5% and 42.7% for pre-loaded and post-loaded NPs, respectively. Compared to free QLNWD, NP encapsulation significantly enhanced the uptake of QLNWD by macrophages. Thus, GBA NPs, particularly those prepared by the pre-loading method, are considered promising delivery systems for marine bioactive peptides. Full article

Since the first paper published by Susan Cole in 1990 detailing multidrug resistance mediated by ABCC1/MRP1, research into the C-subfamily of ATP-binding cassette transporters has continued to uncover a wide range of functionally divergent proteins. However, several orphan transporters remain in the C-subfamily, and the physiological function and substrates of ABCC5, ABCC11, and ABCC12 remain elusive. This review explores the emerging understanding of human ABCC5. Unlike other ABC transporters with well-defined drug export functions, ABCC5’s physiological roles remain only partially understood. While it is known for its involvement in multidrug resistance in cancers, recent studies suggest broader implications in development, metabolism, neurobiology, and male fertility. ABCC5 exports various endogenous substrates, including cyclic nucleotides (cAMP and cGMP), glutamate conjugates like NAAG, and possibly haem. Knockout models in mice, zebrafish, and sea urchins reveal ABCC5’s role in gut formation, brain function, eye development, and iron metabolism. In mice, its deletion results in lower adipose tissue mass, enhanced insulin sensitivity, and neurobehavioral changes resembling schizophrenia, highlighting its role in glutamatergic signalling and circadian regulation. Functionally, ABCC5 appears to impact adipocyte differentiation and GLP-1 release, implicating it in type 2 diabetes susceptibility in humans. Structural studies using human ABCC5 revealed a novel autoinhibitory mechanism involving a peptide segment (C46–S64) that blocks substrate binding, offering new potential for selective inhibitor development. However, this review emphasises caution in targeting ABCC5 for cancer therapy due to its underappreciated physiological function(s), particularly in the brain and male reproductive system. Understanding ABCC5’s substrate specificity, regulatory mechanisms, and functional redundancy with its paralog ABCC12 remains critical for successful therapeutic strategies in humans. Full article

Background/Objectives: This study explores the potential of the inducible G protein-coupled kinin B1 receptor (B1R) as a target for the diagnosis and treatment of prostate cancer (PCa) and aims to develop the first theranostic agent targeting hB1R for both molecular imaging and radionuclide therapy. Methods: B1R expression was analyzed via qPCR and immunohistochemistry in human PCa cells and tissues specimens. A novel ⁶⁴Cu/NOTA-conjugated peptide analog of the potent B1R antagonist R954 was synthetized and evaluated in vitro and in vivo. Results: B1R was confirmed to be expressed (RNA, protein) by varying degrees in all PCa cell lines and tissues investigated, with protein level significantly correlating with tumor grades. This finding was supported by similar analyses from the TCGA and MSKCC databases. In vitro, the ⁶⁴Cu/NOTA-βAla-R954 conjugate showed nanomolar affinity/potency at hB1R, complete plasma stability over 24 h, significant cellular uptake (up to 33% of ID at 24 h), and dose-dependent anti-clonal growth effects. In vivo, the radioconjugate remained stable in circulation for up to 90 min and was primarily excreted intact via the kidneys following IV administration. Intravenous ⁶⁴Cu/NOTA-βAla-R954 (7.5 MBq) effectively detected subcutaneous PCa xenografts via µPET imaging in male athymic nude mice. At a single higher dose (65 MBq; 50 µg/kg), it significantly reduced tumor growth without observable toxicity. This antitumor effect was associated with increased apoptosis (active caspase-3) and reduced proliferation (Ki67), as shown by immunohistochemistry. In contrast, the nonradioactive ^NatCu/NOTA-βAla-R954 had no therapeutic effect at the same dose. Conclusions: Our findings provide proof-of-concept for the potential theranostic use of ⁶⁴Cu/NOTA-R954 in PCa, and potentially other types of B1R-positive solid cancers. Full article