Peptide-based Drug Delivery Systems Research Articles

Engineering peptide drug therapeutics through chemical conjugation and implication in clinics.

The development of peptide drugs has made tremendous progress in the past few decades because of the advancements in modification chemistry and analytical technologies. The novel-designed peptide drugs have been modified through various biochemical methods with improved diagnostic, therapeutic, and drug-delivery strategies. Researchers found it a helping hand to overcome the inherent limitations of peptides and bring continued advancements in their applications. Furthermore, the emergence of peptide-drug conjugates (PDCs)-utilizes target-oriented peptide moieties as a vehicle for cytotoxic payloads via conjugation with cleavable chemical agents, resulting in the key foundation of the new era of targeted peptide drugs. This review summarizes the various classifications of peptide drugs, suitable chemical modification strategies to improve the ADME (adsorption, distribution, metabolism, and excretion) features of peptide drugs, and recent (2015-early 2024) progress/achievements in peptide-based drug delivery systems as well as their fruitful implication in preclinical and clinical studies. Furthermore, we also summarized the brief description of other types of PDCs, including peptide-MOF conjugates and peptide-UCNP conjugates. The principal aim is to provide scattered and diversified knowledge in one place and to help researchers understand the pinching knots in the science of PDC development and progress toward a bright future of novel peptide drugs.

Mitochondrial Localized In Situ Self-Assembly Reprogramming Tumor Immune and Metabolic Microenvironment for Enhanced Cancer Therapy.

The inherent immune and metabolic tumor microenvironment (TME) of most solid tumors adversely affect the antitumor efficacy of various treatments, which is an urgent issue to be solved in clinical cancer therapy. In this study, a mitochondrial localized in situ self-assembly system is constructed to remodel the TME by improving immunogenicity and disrupting the metabolic plasticity of cancer cells. The peptide-based drug delivery system can be pre-assembled into nanomicelles in vitro and form functional nanofibers on mitochondria through a cascade-responsive process involving reductive release, targeted enrichment, and in situ self-assembly. The organelle-specific in situ self-assemblyeffectively switches the role of mitophagy from pro-survival to pro-death, which finally induces intense endoplasmic reticulum stress and atypical type II immunogenic cell death. Disintegration of the mitochondrial ultrastructure also impedes the metabolic plasticity of tumor cells, which greatly promotes the immunosuppresive TME remodeling into an immunostimulatory TME. Ultimately, the mitochondrial localized in situ self-assembly system effectively suppresses tumor metastases, and converts cold tumors into hot tumors with enhanced sensitivity to radiotherapy and immune checkpoint blockade therapy. This study offers a universal strategy for spatiotemporally controlling supramolecular self-assembly on sub-organelles to determine cancer cell fate and enhance cancer therapy.

Cellular uptake and trafficking of peptide-based drug delivery systems for miRNA

Today, macromolecular compounds such as microRNAs (miRNAs) are becoming more and more widespread as leading therapeutics. However, their application is limited mostly due to their poor stability, limited cellular uptake, and poor target specificity. Cell-penetrating peptides (CPPs), a group of positively charged peptides, represent a breakthrough as delivery systems for macromolecules. In the present study, we used two types of nanoparticles which differ in the type of CPP used for their manufacturing. The first type is composed of protamine, an arginine rich CPP, which is highly positively charged. The arginine residues are able to form electrostatic interactions with miRNAs, stabilize them, and deliver them to cells. The second type is composed of the N-Ter peptide (also known as MPG), an amphipathic peptide rich in lysine. The positively charged parts of the N-Ter peptide electrostatically stabilize miRNAs, whereas its amphipathic character allows it to successfully traverse cell membranes. We used miRNA-27a, a negative regulator of adipogenesis, to form nanoparticles with the peptides and traced their uptake in 3T3-L1 preadipocytes. Motivated by the lengthy discourse regarding the uptake mechanism of CPPs, the focus of our study was to analyse and understand the internalization of proticles (protamine nanoparticles) and N-Ter complexes.The nanoparticles were characterized regarding size, size distribution, and zeta potential, and their cytotoxicity was tested in 3T3-L1 cells. The uptake studies were performed by varying the experimental conditions such as time, concentration, and temperature, as well as by applying different inhibitors of endocytosis. Furthermore, we assessed the biological effect of miRNA-27a on the pro-adipogenic machinery. The obtained data have shown that protamine and the N-Ter peptide form positively charged nanoparticles through non-covalent complexation. The uptake of proticles and N-Ter complexes was found to be dependent on time, concentration, and temperature, and different uptake pathways were discovered to be involved in the internalization of the different nanoparticles. Furthermore, both types of nanoparticles induced the anti-adipogenic effect of miRNA-27a, demonstrating that this approach can be used as a novel miRNA replacement therapy in the treatment of obesity and obesity-related disorders.

Cancer Stem-like Cells-Oriented Surface Self-Assembly to Conquer Radioresistance.

Cancer stem-like cells (CSCs), capable of indefinite self-renewal and differentiation, are considered to be the root cause of tumor radiotherapy (RT) resistance. However, the CSCs-targeted therapy still remains to be a great challenge because they are commonly located in the deep tumor making drugs hard to approach, and their hypoxic and acidic niche can further aggravate radioresistance. Herein, based on our finding that hypoxic CSCs highly express carbonic anhydrase IX (CAIX) on the cell membrane, a CAIX-targeted induced in situ self-assembly system on the surface of CSC is reported to overcome hypoxic CSC-mediated radioresistance. Via the sequential processes of "monomer release-target accumulation-surface self-assembly," the constructed peptide-based drug delivery system (CA-Pt) exhibits the advantages of deep penetration, amplified CAIX inhibition, and enhanced cellular uptake, which greatly relieves the hypoxic and acidic microenvironment to promote the hypoxic CSC differentiation and combines with platinum to boost the RT-inducing DNA damage. In both lung cancer tumor mouse and zebrafish embryo models, CA-Pt treatment can effectively assist RT in suppressing tumor growth and preventing tumor invasion and metastasis. This study used a surface-induced self-assembly strategy to differentiate hypoxic CSCs, which may provide a universal treatment strategy for overcoming tumor radioresistance. This article is protected by copyright. All rights reserved.

Hybrid peptides as platform for synchronized combination therapy

Combination therapy, where two or more therapeutic agents are combined to target different cellular pathways, is an effective tool in cancer treatment but often difficult to execute. Here we present the collagen peptide-based platform that allows for synchronous and colocalized cellular delivery of three different agents. The peptide is a hybrid between collagen and cell penetrating peptide (CPP) that assembles into a heterotrimer helix and forms fully organic, high aspect ratio nanoparticles. The validity of the approach was tested with three chemically different agents (Paclitaxel, Doxorubicin, and 5-Fluorouracil; a combination used in clinical treatment of (ER)-positive and (PR)-positive breast cancer) conjugated to N-terminus of the peptide. The design of this peptide-based drug delivery system provides several advantages: it avoids drug loading problems; removes the need for orthogonal synthesis; and allows for colocalized delivery of up to three drugs (which leads to the same biodistribution for each drug). In addition, hybrid collagen/CPP peptides are known to enhance cellular uptake and improve solubility of drugs. The synergistic effect, in terms of enhanced efficacy, of the Paclitaxel-Doxorubicin-5-Fluorouracil combination was also calculated. We envision self-assembling peptides as a platform for drug codelivery that can be expanded into a library of personalized combinations that may also include other functionalities like targeting or imaging.

A Research on Future Scenario in the Field Of Role of Nanorobotics a Device for Diagnosis and Treatment

Nanorobots are the nano devices that are used for protecting or treatment against pathogens in humans. The use of nanorobots technology has become familiar and increasingly common, especially with pharmaceutical technology. We conducted this research paper by observing the different types of reviews, as well as conducting and evaluating literature review papers. This research is provided detailed overview of the types, properties and application of nanorobot in the diagnosis, prevention and treatment of various diseases. Nanorobots technology is rapidly emerging in the medical field, and this subfield has been termed nanomedicine. Nanorobotics are developing wide potential applications across all fields of medicine, and expanding the number of therapeutic options available, while also improving the efficacy of existing treatments. The most recent applications of these devices include targeted drug delivery to the brain, glucose monitoring in patients with diabetes, bone reconstruction, cancer treatment, blood clot removal, nerve regeneration and protein peptide based drug delivery systems.

Insights into current directions of protein and peptide-based hydrogel drug delivery systems for inflammation

Insights into current directions of protein and peptide-based hydrogel drug delivery systems for inflammation

De Novo Self-Assembling Peptides Mediate the Conversion of Temozolomide and Delivery of a Model Drug into Glioblastoma Multiforme Cells

Glioblastoma multiforme (GBM) is the most aggressive central nervous system tumor, and standard treatment, including surgical resection, radiation, and chemotherapy, has not significantly improved patient outcomes over the last 20 years. Temozolomide (TMZ), the prodrug most commonly used to treat GBM, must pass the blood–brain barrier and requires a basic pH to convert to its active form. Due to these barriers, less than 30% of orally delivered TMZ reaches the central nervous system and becomes bioactive. In this work, we have developed a novel biomaterial delivery system to convert TMZ to its active form and that shows promise for intracellular TMZ delivery. Self-assembling peptides were characterized under several different assembly conditions and evaluated for TMZ loading and conversion. Both solvent and method of assembly were found to affect the supramolecular and secondary structure of peptide assemblies. Additionally, as peptides degraded in phosphate-buffered saline, TMZ was rapidly converted to its active form. This work demonstrates that peptide-based drug delivery systems can effectively create a local stimulus during drug delivery while remaining biocompatible. This principle could be used in many future biomedical applications in addition to cancer treatment, such as wound healing and regenerative medicine.

Delivery of Small Molecules by Syndiotactic Peptides for Breast Cancer Therapy.

The utilization of peptide-based drug delivery systems has been suboptimal due to their poor proteolytic susceptibility, poor cell permeability, and limited tumor homing capabilities. Earlier attempts in using d-enantiomers in peptide sequences increased proteolytic stability but have compromised the overall penetration capability. We designed a series of peptides (STRAPs) with a syndiotactic polypeptide backbone that can potentially form a spatial array of cationic groups, an important feature that facilitates cellular uptake. The peptides penetrate cell membranes through a combination of active and passive modes. Furthermore, the cellular uptake of the peptides was unaffected by the presence of or treatment with bovine serum and human plasma. The designed peptides successfully delivered methotrexate, an anticancer drug, to the in vitro and in vivo models of breast cancer, with the best performing peptide STRAP-4-MTX conjugate having an EC50 value of 1.34 μM. Peptide drug delivery in mouse xenograft models showed a greater reduction of primary tumor and metastasis of breast cancer, in comparison to methotrexate of the same dose. The in vivo biodistribution assay of the STRAP-4 peptide suggests that the peptide accumulates at the tumor site after 2 h of treatment, and in the absence of tumors, the peptide gets metabolized and excreted from the system.

Peptide-Based Drug Delivery Systems.

Peptide-based drug delivery systems have many advantages when compared to synthetic systems in that they have better biocompatibility, biochemical and biophysical properties, lack of toxicity, controlled molecular weight via solid phase synthesis and purification. Lysosomes, solid lipid nanoparticles, dendrimers, polymeric micelles can be applied by intravenous administration, however they are of artificial nature and thus may induce side effects and possess lack of ability to penetrate the blood-brain barrier. An analysis of nontoxic drug delivery systems and an establishment of prospective trends in the development of drug delivery systems was needed. This review paper summarizes data, mainly from the past 5 years, devoted to the use of peptide-based carriers for delivery of various toxic drugs, mostly anticancer or drugs with limiting bioavailability. Peptide-based drug delivery platforms are utilized as peptide–drug conjugates, injectable biodegradable particles and depots for delivering small molecule pharmaceutical substances (500 Da) and therapeutic proteins. Controlled drug delivery systems that can effectively deliver anticancer and peptide-based drugs leading to accelerated recovery without significant side effects are discussed. Moreover, cell penetrating peptides and their molecular mechanisms as targeting peptides, as well as stimuli responsive (enzyme-responsive and pH-responsive) peptides and peptide-based self-assembly scaffolds are also reviewed.

Preparation and characterization of BSA as a model protein loaded chitosan nanoparticles for the development of protein-/peptide-based drug delivery system

BackgroundThe purpose of this study was to develop protein-/peptide-loaded nanoparticle-based delivery system, which can efficiently deliver therapeutic molecules to the lung via pulmonary delivery. The chitosan nanoparticles were prepared by the ionic gelation method, and bovine serum albumin was used as a model protein. These nanoparticles were characterized for size, zeta potential, encapsulation efficiency, cell cytotoxicity, uptake study, release profile and size distribution and uniformity. The chemical interaction of chitosan and protein was studied by XRD and FTIR. The integrity assessment of encapsulated protein into nanoparticle was studied by native and SDS-PAGE gel electrophoresis.ResultsThe size and zeta potential of BSA nanoparticles were 193.53 ± 44.97 to 336.36 ± 94.63 and 12.73 ± 0.41 to 18.33 ± 0.96, respectively, with PDI values of 0.35–0.45. The encapsulation efficiency was in the range of 80.73 ± 6.37% to 92.34 ± 1.72%. The cumulative release of the BSA from the nanoparticles was 72.56 ± 6.67% in 2 weeks. The BSA-loaded nanoparticles showed good uptake and no significant cytotoxicity observed into the A549 cell line. In this study, it was also observed that during nanoparticles’ synthesis protein structure and integrity is not compromised. The nanoparticles showed controlled and sustained release with initial burst release. In TEM images, it was shown that nanoparticles’ distribution is uniform within nanometre range.ConclusionFrom this study, it was concluded that nanoparticles prepared by this method are suitable to deliver protein/peptide into the cells without any degradation of protein during process of nanoparticle fabrication.

The Cysteine-Containing Cell-Penetrating Peptide AP Enables Efficient Macromolecule Delivery to T Cells and Controls Autoimmune Encephalomyelitis.

T cells are key immune cells involved in the pathogenesis of several diseases, rendering them important therapeutic targets. Although drug delivery to T cells is the subject of continuous research, it remains challenging to deliver drugs to primary T cells. Here, we used a peptide-based drug delivery system, AP, which was previously developed as a transdermal delivery peptide, to modulate T cell function. We first identified that AP-conjugated enhanced green fluorescent protein (EGFP) was efficiently delivered to non-phagocytic human T cells. We also confirmed that a nine-amino acid sequence with one cysteine residue was the optimal sequence for protein delivery to T cells. Next, we identified the biodistribution of AP-dTomato protein in vivo after systemic administration, and transduced it to various tissues, such as the spleen, liver, intestines, and even to the brain across the blood–brain barrier. Next, to confirm AP-based T cell regulation, we synthesized the AP-conjugated cytoplasmic domain of CTLA-4, AP-ctCTLA-4 peptide. AP-ctCTLA-4 reduced IL-17A expression under Th17 differentiation conditions in vitro and ameliorated experimental autoimmune encephalomyelitis, with decreased numbers of pathogenic IL-17A+GM-CSF+ CD4 T cells. These results collectively suggest the AP peptide can be used for the successful intracellular regulation of T cell function, especially in the CNS.

Drug-Bearing Peptide-Based Nanospheres for the Inhibition of Metastasis and Growth of Cancer.

Employing a peptide-based nanoscale drug delivery system is an effective strategy to overcome the poor therapeutic outcomes of chemotherapeutic drugs. Here, we developed a self-assembling peptide-drug delivery system comprising a self-assembling anticancer peptide (R-lycosin-I), as revealed in our previous study, and 10-hydroxycamptothecin (HCPT) for cancer therapy. The results showed that peptide-drug conjugates (R-L-HCPT) could assemble into nanospheres of 40-60 nm in water. Compared with free HCPT, R-L-HCPT nanospheres not only inhibited tumor growth but also suppressed pulmonary metastatic nodules on B16-F10 cells in vivo. In summary, these results indicated that the self-assembling R-lycosin-I could provide a promising nanoscale platform for delivering small-molecule drugs. Moreover, our study might provide new opportunities for the development of a new class of functional peptide-drug-conjugated systems based on nanomaterials, which could synergistically enhance anticancer outcomes.

Phage Display-Based Homing Peptide-Daunomycin Conjugates for Selective Drug Targeting to PANC-1 Pancreatic Cancer.

The Pancreatic Ductal Adenocarcinoma (PDAC) is one of the most aggressive and dangerous cancerous diseases, leading to a high rate of mortality. Therefore, the development of new, more efficient treatment approaches is necessary to cure this illness. Peptide-based drug targeting provides a new tool for this purpose. Previously, a hexapeptide Cys-Lys-Ala-Ala-Lys-Asn (CKAAKN) was applied efficiently as the homing device for drug-loaded nanostructures in PDAC cells. In this research, Cys was replaced by Ser in the sequence and this new SKAAKN targeting moiety was used in conjugates containing daunomycin (Dau). Five different structures were developed and tested. The results indicated that linear versions with one Dau were not effective on PANC-1 cells in vitro; however, branched conjugates with two Dau molecules showed significant antitumor activity. Differences in the antitumor effect of the conjugates could be explained with the different cellular uptake and lysosomal degradation. The most efficient conjugate was Dau=Aoa-GFLG-K(Dau=Aoa)SKAAKN-OH (conjugate 4) that also showed significant tumor growth inhibition on s.c. implanted PANC-1 tumor-bearing mice with negligible side effects. Our novel results suggest that peptide-based drug delivery systems could be a promising tool for the treatment of pancreatic cancers.

A New NT4 Peptide-Based Drug Delivery System for Cancer Treatment.

The development of selective tumor targeting agents to deliver multiple units of chemotherapy drugs to cancer tissue would improve treatment efficacy and greatly advance progress in cancer therapy. Here we report a new drug delivery system based on a tetrabranched peptide known as NT4, which is a promising cancer theranostic by virtue of its high cancer selectivity. We developed NT4 directly conjugated with one, two, or three units of paclitaxel and an NT4-based nanosystem, using NIR-emitting quantum dots, loaded with the NT4 tumor-targeting agent and conjugated with paclitaxel, to obtain a NT4-QD-PTX nanodevice designed to simultaneously detect and kill tumor cells. The selective binding and in vitro cytotoxicity of NT4-QD-PTX were higher than for unlabeled QD-PTX when tested on the human colon adenocarcinoma cell line HT-29. NT4-QD-PTX tumor-targeted nanoparticles can be considered promising for early tumor detection and for the development of effective treatments combining simultaneous therapy and diagnosis.

Functional peptide-based drug delivery systems.

Peptides are one of the most important functional motifs for constructing smart drug delivery systems (DDSs). Functional peptides can be conjugated with drugs or carriers via covalent bonds, or assembled into DDSs via supramolecular forces, which enables the DDSs to acquire desired functions such as targeting and/or environmental responsiveness. In this mini review, we first introduce the different types of functional peptides that are commonly used for constructing DDSs, and we highlight representative strategies for designing smart DDSs by using functional peptides in the past few years. We also state the challenges of peptide-based DDSs and come up with prospects.

Dual Stimuli-Responsive Peptide-Based Palladium Nano-Lychee Spheres for Synergistic Antitumor Therapy.

The application of peptide-based biomaterials in nanocarriers can effectively reduce toxicity and improve the biocompatibility. In our study, a dual stimuli-responsive peptide-based drug delivery system was designed and synthesized, which was nontoxic and achieved the chem-photothermal therapy synergistic effect. Lanreotide (Lan), a kind of somatostatin analogue, was used as internal template to prepared lychee-shaped palladium (Pd) nanoparticles (Lan-PdNPs). Glutathione (GSH) and doxorubicin (DOX) were combined on the surface of Lan-PdNPs to obtain the nanosystem of Lan-PdNPs@GSH/DOX. Based on the lychee-shaped structures, the system demonstrated higher photothermal conversion performance and photothermal stability. Under NIR laser irradiation, Lan-PdNPs@GSH/DOX could convert light energy to heat in effect and accelerate drug release. Moreover, in acidic conditions, the system also exhibited the pH-responsive drug release. Owing to the synergism, the antitumor effects of Lan-PdNPs@GSH/DOX in vitro and in vivo were superior, and the inhibition ratio was much higher than that of chemotherapy or photothermal therapy alone. The good biocompatibility and nontoxicity of the system also provide the possibility for serving as an antitumor drug candidate.

A Protocol To Characterize Peptide-Based Drug Delivery Systems for miRNAs.

Micro RNA (miRNA)-based medicines have attracted attention as new therapeutic strategies to treat genetic diseases and metabolic and immunological disorders. MiRNAs have emerged as key mediators of metabolic processes fulfilling regulatory functions in maintaining physiological conditions, while altered miRNA expression profiles are often associated with genetic diseases. However, naked miRNAs exhibit poor enzymatic stability, biomembrane permeation, and cellular uptake. To overcome these limitations, the development of appropriate drug delivery systems (DDS) is necessary. Herein, a DDS is characterized being assembled from miRNA-27a (negative regulator in fat metabolism) and the amphipathic N-TER peptide. Dynamic light scattering (DLS), electrophoretic light scattering, and atomic force microscopy (AFM) are used to investigate physicochemical properties (i.e., size, shape, and charge) of the DDS. Although surface charges should provide decent stabilization, the AFM results confirm a state of agglomeration, which is also suggested by DLS. Furthermore, AFM studies reveal adhesion on hydrophilic as well as hydrophobic substrates, which is related to the amphipathic properties of the N-TER peptide. Physicochemical properties of DDS are important parameters, which have an impact on cell internalization/uptake and have to be taken into account for in vitro studies to develop a successful peptide-based DDS for miRNA replacement therapy in metabolic diseases, such as obesity and others.

Peptide-Based Drug-Delivery Systems in Biotechnological Applications: Recent Advances and Perspectives.

Peptides of natural and synthetic sources are compounds operating in a wide range of biological interactions. They play a key role in biotechnological applications as both therapeutic and diagnostic tools. They are easily synthesized thanks to solid-phase peptide devices where the amino acid sequence can be exactly selected at molecular levels, by tuning the basic units. Recently, peptides achieved resounding success in drug delivery and in nanomedicine smart applications. These applications are the most significant challenge of recent decades: they can selectively deliver drugs to only pathological tissues whilst saving the other districts of the body. This specific feature allows a reduction in the drug side effects and increases the drug efficacy. In this context, peptide-based aggregates present many advantages, including biocompatibility, high drug loading capacities, chemical diversity, specific targeting, and stimuli responsive drug delivery. A dual behavior is observed: on the one hand they can fulfill a structural and bioactive role. In this review, we focus on the design and the characterization of drug delivery systems using peptide-based carriers; moreover, we will also highlight the peptide ability to self-assemble and to actively address nanosystems toward specific targets.

In situ hydrogelation of forky peptides in prostate tissue for drug delivery.

Herein, we have designed and synthesized a novel forky peptide D3F3 that transforms into a hydrogel through crosslinking induced by ZIs stimuli. We have employed D3F3 as a suitable drug carrier that is conjugated with DOX. Since the concentration of zinc ions necessary for triggering gelation falls into the physiological range present in prostate tissue, while other cationic ions fail to trigger at physiological concentrations, the peptide-based drug delivery system (DDS) is injectable and would achieve prostate tissue-specific self-assembly in situ. The D3F3 hydrogels exhibited an optimal gelation time, satisfactory mechanical strength (can be enhanced after incorporation of DOX) as well as excellent thixotropic properties. The DDS reserved some DOX in the prostate 24 h after the injection, making local sustained release possible. In addition, the peptide materials demonstrated no cytotoxicity against normal fibroblast cells and no damage was observed to the prostate tissue of rats. The drug release followed a non-Fickian diffusion model, with no burst release observed. Importantly, the DOX-hydrogel system exhibited good anti-cancer efficacy when incubated with prostate cancer cells DU-145. Therefore, this study lays the groundwork for the future design of tissue-specific DDSs that are triggered by cationic ions (e.g. zinc ions), and the platform could be further developed to incorporate other potent drugs utilized in the field of prostate cancer therapy, thereby increasing their potency and reducing their side effects.