Acid-Induced Activated Cell-Penetrating Peptide-Modified Cholesterol-Conjugated Polyoxyethylene Sorbitol Oleate Mixed Micelles for pH-Triggered Drug Release and Efficient Brain Tumor Targeting Based on a Charge Reversal Mechanism

Cholesterol-modified peptide nanomicelles as a promising platform for cancer therapy: A review

Drug resistance, systemic toxicity, low solubility, and rapid clearance are common issues with chemotherapy drugs and other molecules used to treat cancer. The development of new therapeutic compounds and nanotherapy offers a solution to these issues. Therapeutic peptides have attracted great interest among these molecules due to their unique advantages, including low immunogenicity, efficient cellular internalization, deep tissue penetration, and low systemic toxicity. They have shown promise in cancer treatment by inducing apoptosis, necrosis, or cell lysis and promoting immunotherapy. In addition, peptides can deliver a range of cargoes, such as drugs, nucleic acids, imaging agents, and nanoparticles, and can specifically target cancer cells. However, problems such as their short half-life and low solubility limit their therapeutic use. Recent developments have addressed these constraints through structural alterations and nanoparticle formulations. In particular, cholesterol modification makes it possible for peptides to self-assemble into nanomicelles, which enhances their stability, half-life, and cell penetration. In this review, therapeutic peptides are presented as a versatile and successful cancer treatment option. The potential of cholesterol-modified peptide micelles as a reliable drug, nucleic acid, and imaging agent delivery system is also examined.

Analytical and drug delivery strategies for short peptides: From manufacturing to market

In recent times, biopharmaceuticals have gained attention because of their tremendous potential to benefit millions of patients globally by treating widespread diseases such as cancer, diabetes and many rare diseases. Short peptides (SP), also termed as oligopeptides, are one such class of biopharmaceuticals, that are majorly involved in efficient functioning of biological systems. Peptide chains that are 2-20 amino acids long are considered as oligopeptides by researchers and are some of the functionally vital compounds with widespread applications including self-assembly material for drug delivery, targeting ligands for precise/specific targeting and other biological uses. Using functionalised biomacromolecules such as short chained peptides, helps in improving pharmacokinetic properties and biodistribution profile of the drug. Apart from this, functionalised SP are being employed as cell penetrating peptides and prodrug to specifically and selectively target tumor sites. In order to minimize any unwanted interaction and adverse effects, the stability and safety of SP should be ensured throughout its development from manufacturing to market. Formulation development and characterization strategies of these potential molecules are described in the following review along with various applications and details of marketed formulations.

Recent progress in stimuli-responsive polymeric micelles for targeted delivery of functional nanoparticles

Stimuli-responsive polymeric micelles have emerged as a revolutionary approach for enhancing the in vivo stability, biocompatibility, and targeted delivery of functional nanoparticles (FNPs) in biomedicine. This article comprehensively reviews the preparation methods of these polymer micelles, detailing the innovative strategies employed to introduce stimulus responsiveness and surface modifications essential for precise targeting. We delve into the breakthroughs in utilizing these micelles to selectively deliver various FNPs including magnetic nanoparticles, upconversion nanoparticles, gold nanoparticles, and quantum dots, highlighting their transformative impact in the biomedical realm. Concluding, we present an insight into the current research landscape, addressing the challenges at hand, and envisioning the future trajectory in this burgeoning domain. Join us as we navigate the exciting confluence of polymer science and nanotechnology in reshaping biomedical solutions.

Peptide-Hitchhiking for the Development of Nanosystems in Glioblastoma

Glioblastoma (GBM) remains the epitome of aggressiveness and lethality in the spectrum of brain tumors, primarily due to the blood-brain barrier (BBB) that hinders effective treatment delivery, tumor heterogeneity, and the presence of treatment-resistant stem cells that contribute to tumor recurrence. Nanoparticles (NPs) have been used to overcome these obstacles by attaching targeting ligands to enhance therapeutic efficacy. Among these ligands, peptides stand out due to their ease of synthesis and high selectivity. This article aims to review single and multiligand strategies critically. In addition, it highlights other strategies that integrate the effects of external stimuli, biomimetic approaches, and chemical approaches as nanocatalytic medicine, revealing their significant potential in treating GBM with peptide-functionalized NPs. Alternative routes of parenteral administration, specifically nose-to-brain delivery and local treatment within the resected tumor cavity, are also discussed. Finally, an overview of the significant obstacles and potential strategies to overcome them are discussed to provide a perspective on this promising field of GBM therapy.

Dessecting the toxicological profile of polysorbate 80 (PS80): comparative analysis of constituent variability and biological impact using a zebrafish model

Polysorbate 80, commonly abbreviated as PS80, is a widely used pharmaceutical excipient renowned for its role as a solubilizer and stabilizer in drug formulations. Although PS80 is essential for various pharmaceutical applications, particularly in the formulation of injectable drugs, it has been implicated in a range of adverse reactions. However, due to the complexity of the composition of PS80, the differences in the types and contents of the constituents of PS80 from different manufacturers increase the probability or likelihood of their uneven quality. Addressing the complete spectrum of PS80's components is challenging; thus, most studies to date have examined PS80 as a singular entity. This approach, however, carries a degree of uncertainty, as it overlooks the unique composition and concentration of components within the PS80 used in experiments, which may not reflect the actual diversity in commercially available PS80 products. Recognizing the critical need to understand how PS80's composition influences biological effects and toxicity, our study aims to bridge this knowledge gap. By doing so, we can clarify how different PS80 compositions from various manufacturers might affect the quality of pharmaceutical formulations, and also guide excipient manufacturers toward producing higher-quality PS80. Such insights could further facilitate a more targeted application of PS80 in drug development. Building on our previous work, we isolated and prepared two key components of PS80-polyoxyethylene sorbitan monooleate (PSM) and polyoxyethylene isosorbide monooleate (PIM)-and conducted a systematic comparison. We evaluated the acute, hemolytic, and target organ toxicity of two different PS80 samples, as well as PSM and PIM, using a zebrafish model. Our research also delved into the potential mechanisms behind the observed toxicological effects, providing an in-depth understanding of PS80's impact on biological systems.The results show that PS80, PSM, and PIM resulted in developmental anomalies in larval zebrafish. The primary organs of acute toxicity in zebrafish exposed to PS80 and its typical components PSM and PIM include the cardiovascular system, kidneys, intestines, skin, and liver. Notably, PIM further induced severe pericardial edema and erythrocyte hemolysis, thereby affecting blood flow. The samples also instigated oxidative damage by disrupting the redox equilibrium in the larvae. Compared to PS80, both PSM and PIM induced greater oxidative damage, with PIM notably causing significantly higher lipid oxidation, suggesting that oxidative stress may play a crucial role in polysorbate80-induced toxicity. Furthermore, our study found that PS80 could induce alterations in DNA conformation. The findings underscore the necessity for excipient regulators to establish comprehensive quality standards for Polysorbate 80 (PS80). By implementing such standards, it is possible to minimize the clinical risks associated with the variability in PS80 composition, ensuring safer pharmaceutical products for patients.

Acid-Activated TAT Peptide-Modified Biomimetic Boron Nitride Nanoparticles for Enhanced Targeted Codelivery of Doxorubicin and Indocyanine Green: A Synergistic Cancer Photothermal and Chemotherapeutic Approach

The evolution of nano-drug delivery systems addresses the limitations of conventional cancer treatments with stimulus-responsive nanomaterial-based delivery systems presenting temporal and spatial advantages. Among various nanomaterials, boron nitride nanoparticles (BNNs) demonstrate significant potential in drug delivery and cancer treatment, providing a high drug loading capacity, multifunctionality, and low toxicity. However, the challenge lies in augmenting nanomaterial accumulation exclusively within tumors while preserving healthy tissues. To address this, we introduce a novel approach involving cancer cell membrane-functionalized BNNs (CM-BIDdT) for the codelivery of doxorubicin (Dox) and indocyanine green to treat homologous tumor. The cancer cell membrane biomimetic CM-BIDdT nanoparticles possess highly efficient homologous targeting capabilities toward tumor cells. The surface modification with acylated TAT peptides (dTAT) further enhances the nanoparticle intracellular accumulation. Consequently, CM-BIDdT nanoparticles, responsive to the acidic tumor microenvironment, hydrolyze amide bonds, activate the transmembrane penetrating function, and achieve precise targeting with substantial accumulation at the tumor site. Additionally, the photothermal effect of CM-BIDdT under laser irradiation not only kills cells through thermal ablation but also destroys the membrane on the surface of the nanoparticles, facilitating Dox release. Therefore, the fabricated CM-BIDdT nanoparticles orchestrate chemo-photothermal combination therapy and effectively inhibit tumor growth with minimal adverse effects, holding promise as a new modality for synergistic cancer treatment.

Conjugation to a cell-penetrating peptide drives the tumour accumulation of the GLP1R antagonist exendin(9-39)

PURPOSE

Exendin, an analogue of the glucagon-like peptide 1 (GLP1), is an excellent tracer for molecular imaging of pancreatic beta cells and beta cell-derived tumours. The commonly used form, exendin-4, activates the GLP1 receptor and causes internalisation of the peptide-receptor complex. As a consequence, injection of exendin-4 can lead to adverse effects such as nausea, vomiting and hypoglycaemia and thus requires close monitoring during application. By comparison, the antagonist exendin(9-39) does not activate the receptor, but its lack of internalisation has precluded its use as a tracer. Improving the cellular uptake of exendin(9-39) could turn it into a useful alternative tracer with less side-effects than exendin-4.

METHODS

We conjugated exendin-4 and exendin(9-39) to the well-known cell-penetrating peptide (CPP) penetratin. We evaluated cell binding and internalisation of the radiolabelled peptides in vitro and their biodistribution in vivo.

RESULTS

Exendin-4 showed internalisation irrespective of the presence of the CPP, whereas for exendin(9-39) only the penetratin conjugate internalised. Conjugation to the CPP also enhanced the in vivo tumour uptake and retention of exendin(9-39).

CONCLUSION

We demonstrate that penetratin robustly improves internalisation and tumour retention of exendin(9-39), opening new avenues for antagonist-based in vivo imaging of GLP1R.

Strategies to overcome/penetrate the BBB for systemic nanoparticle delivery to the brain/brain tumor

Despite its prevalence in the management of peripheral tumors, compared to surgery and radiation therapy, chemotherapy is still a suboptimal intervention in fighting against brain cancer and cancer brain metastases. This discrepancy is mainly derived from the complicatedly physiological characteristic of intracranial tumors, including the presence of blood-brain barrier (BBB) and limited enhanced permeability and retention (EPR) effect attributed to blood-brain tumor barrier (BBTB), which largely lead to insufficient therapeutics penetrating to tumor lesions to produce pharmacological effects. Therefore, dependable methodologies that can boost the efficacy of chemotherapy for brain tumors are urgently needed. Recently, nanomedicines have shown great therapeutic potential in brain tumors by employing various transcellular strategies, paracellular strategies, and their hybrids, such as adsorptive-mediated transcytosis, receptor-mediated transcytosis, BBB disruption technology, and so on. It is compulsory to comprehensively summarize these practices to shed light on future directions in developing therapeutic regimens for brain tumors. In this review, the biological and pathological characteristics of brain tumors, including BBB and BBTB, are illustrated. After that, the emerging delivery strategies for brain tumor management are summarized into different classifications and supported with detailed examples. Finally, the potential challenges and prospects for developing and clinical application of brain tumor-oriented nanomedicine are discussed.

Membrane Internalization Mechanisms and Design Strategies of Arginine-Rich Cell-Penetrating Peptides

Cell-penetrating peptides (CPPs) have been discovered to deliver chemical drugs, nucleic acids, and macromolecules to permeate cell membranes, creating a novel route for exogenous substances to enter cells. Up until now, various sequence structures and fundamental action mechanisms of CPPs have been established. Among them, arginine-rich peptides with unique cell penetration properties have attracted substantial scientific attention. Due to the positively charged essential amino acids of the arginine-rich peptides, they can interact with negatively charged drug molecules and cell membranes through non-covalent interaction, including electrostatic interactions. Significantly, the sequence design and the penetrating mechanisms are critical. In this brief synopsis, we summarize the transmembrane processes and mechanisms of arginine-rich peptides; and outline the relationship between the function of arginine-rich peptides and the number of arginine residues, arginine optical isomers, primary sequence, secondary and ternary structures, etc. Taking advantage of the penetration ability, biomedical applications of arginine-rich peptides have been refreshed, including drug/RNA delivery systems, biosensors, and blood-brain barrier (BBB) penetration. Understanding the membrane internalization mechanisms and design strategies of CPPs will expand their potential applications in clinical trials.

Nanoscale bioconjugates: A review of the structural attributes of drug-loaded nanocarrier conjugates for selective cancer therapy

Nanobioconjugates are nanoscale drug delivery vehicles that have been conjugated to or decorated with biologically active targeting ligands. These targeting ligands can be antibodies, peptides, aptamers, or small molecules such as vitamins or hormones. Most research studies in this field have been devoted to targeting cancer. Moreover, the nanostructures can be designed with an additional level of targeting by being designed to be stimulus-responsive or "smart" by a judicious choice of materials to be incorporated into the hybrid nanostructures. This stimulus could be an acidic pH, raised temperature, enzyme, ultrasound, redox potential, an externally applied magnetic field, or laser irradiation. In this case, the smart capability can increase the accumulation at the tumor site or the on-demand drug release, while the ligand ensures selective binding to the tumor cells. The present review highlights some interesting studies classified according to the nanostructure material. These materials include natural substances (polysaccharides), multi-walled carbon nanotubes (and halloysite nanotubes), metal-organic frameworks and covalent-organic frameworks, metal nanoparticles (gold and silver), and polymeric micelles.

Strategies for improving the safety and RNAi efficacy of noncovalent peptide/siRNA nanocomplexes

In the past decades, the striking development of cationic polypeptides and cell-penetrating peptides (CPPs) tailored for small interfering RNA (siRNA) delivery has been fuelled by the conception of nuclear acid therapy and precision medicine. Owing to their amino acid compositions, inherent secondary structures as well as diverse geometrical shapes, peptides or peptide-containing polymers exhibit good biodegradability, high flexibility, and bio-functional diversity as nonviral siRNA vectors. Also, a variety of noncovalent nanocomplexes could be built via self-assembling and electrostatic interactions between cationic peptides and siRNAs. Although the peptide/siRNA nanocomplex-based RNAi therapies, STP705 and MIR-19, are under clinical trials, a guideline addressing the current bottlenecks of peptide/siRNA nanocomplex delivery is in high demand for future research and development. In this review, we present strategies for improving the safety and RNAi efficacy of noncovalent peptide/siRNA nanocomplexes in the treatment of genetic disorders. Through thorough analysis of those RNAi formulations using different delivery strategies, we seek to shed light on the rationale of peptide design and modification in constructing robust siRNA delivery systems, including targeted and co-delivery systems. Based on this, we provide a timely and comprehensive understanding of how to engineer biocompatible and efficient peptide-based siRNA vectors.

Gather wisdom to overcome barriers: Well-designed nano-drug delivery systems for treating gliomas

Due to the special physiological and pathological characteristics of gliomas, most therapeutic drugs are prevented from entering the brain. To improve the poor prognosis of existing therapies, researchers have been continuously developing non-invasive methods to overcome barriers to gliomas therapy. Although these strategies can be used clinically to overcome the blood‒brain barrier (BBB), the accurate delivery of drugs to the glioma lesions cannot be ensured. Nano-drug delivery systems (NDDS) have been widely used for precise drug delivery. In recent years, researchers have gathered their wisdom to overcome barriers, so many well-designed NDDS have performed prominently in preclinical studies. These meticulous designs mainly include cascade passing through BBB and targeting to glioma lesions, drug release in response to the glioma microenvironment, biomimetic delivery systems based on endogenous cells/extracellular vesicles/protein, and carriers created according to the active ingredients of traditional Chinese medicines. We reviewed these well-designed NDDS in detail. Furthermore, we discussed the current ongoing and completed clinical trials of NDDS for gliomas therapy, and analyzed the challenges and trends faced by clinical translation of these well-designed NDDS.

CPP-Based Bioactive Drug Delivery to Penetrate the Blood-Brain Barrier: A Potential Therapy for Glioblastoma Multiforme

BACKGROUND

A large number of studies have been conducted on the treatment of glioblastoma multiforme (GBM). Chemotherapeutic drugs cannot penetrate deeply into the brain parenchyma due to the presence of the blood-brain barrier (BBB). Hence, crossing BBB is the significant obstacle in developing new therapeutic methods for GBM.

OBJECTIVE

Cell penetrating peptides (CPPs) have emerged as new tools that can efficiently deliver various substances across BBB. CPPs beneficial properties, such as BBB penetration capacity, low toxicity, and the ability to achieve active targeting and controllable drug release, have made them worthy candidates for GBM treatment. However, their application is limited by several drawbacks, including lack of selectivity, insufficient transport efficacy, and low stability. In order to overcome the selectivity issue, tumor targeting peptides and sequences that can be activated at the target site have been embedded into the structure of CPPs. To overcome their insufficient transport efficacy into the cells, which is mostly due to endosomal entrapment, various endosomolytic moieties have been incorporated into CPPs. Finally, their instability in blood circulation can be solved through different modifications to their structures. As this field is moving beyond preclinical studies, the discovery of new and more efficient CPPs for GBM treatment has become crucial. Thus, by using display techniques, such as phage display, this encouraging treatment strategy can be developed further.

CONCLUSION

Consequently, despite several challenges in CPPs application, recent progress in studies has shown their potential for the development of the next generation GBM therapeutics.

Combination of cell-penetrating peptides with nanomaterials for the potential therapeutics of central nervous system disorders: a review

Although nanomedicine have greatly developed and human life span has been extended, we have witnessed the soared incidence of central nervous system (CNS) diseases including neurodegenerative diseases (Alzheimer's disease, Parkinson's disease), ischemic stroke, and brain tumors, which have severely damaged the quality of life and greatly increased the economic and social burdens. Moreover, partial small molecule drugs and almost all large molecule drugs (such as recombinant protein, therapeutic antibody, and nucleic acid) cannot cross the blood-brain barrier. Therefore, it is especially important to develop a drug delivery system that can effectively deliver therapeutic drugs to the central nervous system for the treatment of central nervous system diseases. Cell penetrating peptides (CPPs) provide a potential strategy for the transport of macromolecules through the blood-brain barrier. This study analyzed and summarized the progress of CPPs in CNS diseases from three aspects: CPPs, the conjugates of CPPs and drug, and CPPs modified nanoparticles to provide scientific basis for the application of CPPs for CNS diseases.

The Application of Peptides in Glioma: a Novel Tool for Therapy

BACKGROUND

Glioma is the most aggressive and lethal tumor of the central nervous system. Owing to the cellular heterogeneity, the invasiveness, and blood-brain barrier (BBB), current therapeutic approaches, such as chemotherapy and radiotherapy, are poorly to obtain great anti-tumor efficacy. However, peptides, a novel type of therapeutic agent, displayed excellent ability in the tumor, which becomes a new molecule for glioma treatment.

METHOD

We review the current knowledge on peptides for the treatment of glioma through a PubMed-based literature search.

RESULTS

In the treatment of glioma, peptides can be used as (i) decoration on the surface of the delivery system, facilitating the distribution and accumulation of the anti-tumor drug in the target site;(ii) anti-tumor active molecules, inhibiting the growth of glioma and reducing solid tumor volume; (iii) immune-stimulating factor, and activating immune cells in the tumor microenvironment or recruiting immune cells to the tumor for breaking out the immunosuppression by glioma cells.

CONCLUSION

The application of peptides has revolutionized the treatment of glioma, which is based on targeting, penetrating, anti-tumor activities, and immunostimulatory. Moreover, better outcomes have been discovered in combining different kinds of peptides rather than a single one. Until now, more and more preclinical studies have been developed with multifarious peptides, which show promising results in vitro or vivo with the model of glioma.

Optimized mesoporous silica nanoparticle-based drug delivery system with removable manganese oxide gatekeeper for controlled delivery of doxorubicin

Rapid progress has been made for mesoporous silica nanoparticle (MSN) in recent years; however, efforts to fabricate MSN with adjustable size have been met with limited advancement in drug delivery, especially for the synthesis of MSN with adjustable size in the range of 150-300 nm. Herein we report the construction of a series of MSNs with adjustable specific surface area, size, and pore structure, depending on the different silicon monomers selected. The optimized MSN showed large specific surface area and appropriate size distribution for efficiently anchoring doxorubicin (DOX) through the imine linkage formed. Based on the remarkable features of the unique MSN, a novel MSN-based drug delivery system was prepared through the introduction of polydopamine/manganese oxide (PDA/MnO₂) coating, which reduced the premature leakage of drugs in physiological environments, and yet facilitated drug release when destroyed by responding to endogenous glutathione (GSH) at the tumor sites. Notably, the transformation of MnO₂ to Mn²⁺ resulted in the collapse of the PDA/MnO₂ coating, which facilitated drug release and therefore indicated the controlled release feature. It was demonstrated that the drug-loaded MSN-based drug delivery system delivered drugs into cancer cells and showed effective inhibition against cancer cell growth. These results suggested that the emergence of MSN with adjustable size can expand the application of MSN in drug delivery.

Progress in tumour-targeted drug delivery based on cell-penetrating peptides

Since the discovery of cell-penetrating peptides (CPP) in the 1980s, they have played a unique role in various fields owing to their excellent and unique cell membrane penetration function. In particular, in the treatment of tumours, CPPS have been used to deliver several types of 'cargos' to cancer cells. To address the insufficient targeting ability, non-selectivity, and blood instability, activatable cell-penetrating peptides, which can achieve targeted drug delivery in tumour treatment, enhance curative effects, and reduce toxicity have been developed. This study reviews the application of different cell-penetrating peptides in tumour-targeted delivery, overcoming multidrug resistance, organelle targeting, tumour imaging, and diagnosis, and summarises the different mechanisms of activatable cell-penetrating peptides in detail.

Doxorubicin-Loaded Gold Nanoarchitectures as a Therapeutic Strategy against Diffuse Intrinsic Pontine Glioma

Diffuse Intrinsic Pontine Gliomas (DIPGs) are highly aggressive paediatric brain tumours. Currently, irradiation is the only standard treatment, but is palliative in nature and most patients die within 12 months of diagnosis. Novel therapeutic approaches are urgently needed for the treatment of this devastating disease. We have developed non-persistent gold nano-architectures (NAs) functionalised with human serum albumin (HSA) for the delivery of doxorubicin. Doxorubicin has been previously reported to be cytotoxic in DIPG cells. In this study, we have preclinically evaluated the cytotoxic efficacy of doxorubicin delivered through gold nanoarchitectures (NAs-HSA-Dox). We found that DIPG neurospheres were equally sensitive to doxorubicin and doxorubicin-loaded NAs. Colony formation assays demonstrated greater potency of NAs-HSA-Dox on colony formation compared to doxorubicin. Western blot analysis indicated increased apoptotic markers cleaved Parp, cleaved caspase 3 and phosphorylated H2AX in NAs-HSA-Dox treated DIPG neurospheres. Live cell content and confocal imaging demonstrated significantly higher uptake of NAs-HSA-Dox into DIPG neurospheres compared to doxorubicin alone. Despite the potency of the NAs in vitro, treatment of an orthotopic model of DIPG showed no antitumour effect. This disparate outcome may be due to the integrity of the blood-brain barrier and highlights the need to develop therapies to enhance penetration of drugs into DIPG.

Challenge to overcome current limitations of cell-penetrating peptides

The penetration of biological membranes is a prime obstacle for the delivery of pharmaceutical drugs. Cell-penetrating peptide (CPP) is an efficient vehicle that can deliver various cargos across the biological membranes. Since the discovery, CPPs have been rigorously studied to unveil the underlying penetrating mechanism as well as to exploit CPPs for various biomedical applications. This review will focus on the various strategies to overcome current limitations regarding stability, selectivity, and efficacy of CPPs.

Polymeric Drug Delivery Systems Bearing Cholesterol Moieties: A Review

This review aims to provide an overview of polymers comprising cholesterol moiety/ies designed to be used in drug delivery. Over the last two decades, there have been many papers published in this field, which are summarized in this review. The primary focus of this article is on the methods of synthesis of polymers bearing cholesterol in the main chain or as side chains. The data related to the composition, molecular weight, and molecular weight distribution of polymers are presented. Moreover, other aspects, such as forms of carriers, types of encapsulated drugs, encapsulation efficiency and capacity, are also included.

Folate-Targeted Cholesterol-Grafted Lipo-Polymeric Nanoparticles for Chemotherapeutic Agent Delivery

Docetaxel (DTX), an FDA approved chemotherapeutic agent, is used as a first-line treatment for triple-negative breast cancer (TNBC). Its poor aqueous solubility, rapid metabolism, short half-life, and effective targeting to the cancer cells limits its optimal therapeutic use. Herein, we report folate targeted amphiphilic lipopolymer grafted with cholesterol conjugated carbonate and DL-lactide prepared by microwave assisted ring opening polymerization, for the efficient actively targeted delivery of DTX. The DTX-loaded folate-targeted lipopolymeric nanoparticles (F-DTX-LPNs) prepared by the emulsion solvent evaporation method exhibited a smaller size of ∼115.17 nm with a PDI of 0.205 and encapsulation efficiency of >80%. Further, these lipopolymeric nanoparticles (F-DTX-LPNs) showed a good on-bench stability and sustained DTX release for 7 days. Cell-based assays in MDA-MB-231 cells revealed a significant enhancement in the intracellular uptake of folate-targeted lipopolymeric nanoparticles compared to non-targeted nanoparticles. Further, methyl beta-cyclodextrin (Mβ-CD) completely inhibited the uptake of these nanoparticles in the cells, indicating a lipid raft-mediated uptake mechanism. The developed F-DTX-LPNs showed improved cytotoxicity, apoptosis, and significant fold-change in expression levels of Bcl-2, BAX and Ki-67 as compared to non-targeted DTX-LPNs and free DTX. Further, F-DTX-LPNs showed an improved in vivo pharmacokinetic profile in Sprague Dawley rats as compared to the free DTX. The bio-imaging of ex vivo tissues demonstrated that the DiR loaded folate targeted LPNs exhibited intense signals after 24 h because of slow release of DiR dye from the nanoparticles.

Cell-Penetrating Peptides in Diagnosis and Treatment of Human Diseases: From Preclinical Research to Clinical Application

Cell-penetrating peptides (CPPs) are short peptides (fewer than 30 amino acids) that have been predominantly used in basic and preclinical research during the last 30 years. Since they are not only capable of translocating themselves into cells but also facilitate drug or CPP/cargo complexes to translocate across the plasma membrane, they have potential applications in the disease diagnosis and therapy, including cancer, inflammation, central nervous system disorders, otologic and ocular disorders, and diabetes. However, no CPPs or CPP/cargo complexes have been approved by the US Food and Drug Administration (FDA). Many issues should be addressed before translating CPPs into clinics. In this review, we summarize recent developments and innovations in preclinical studies and clinical trials based on using CPP for improved delivery, which have revealed that CPPs or CPP-based delivery systems present outstanding diagnostic therapeutic delivery potential.

Precise therapeutic effect of self-assembling gold nanocluster-PTEN complexes on an orthotropic model of liver cancer

PURPOSE

Presently, liver cancer is still one of the malignant tumors with high mortality. As far as the treatment of liver cancer is concerned, the most effective method is still liver transplantation. But every year, many liver cancer patients die from the lack of a proper liver transplant, or from waiting for a liver transplant. Therefore, it is very important to find new and effective treatment for patients with liver cancer.

METHODS

Herein, the cell model and the orthotropic liver tumor mice model have been performed to verify the results of our treatment. We found that the in situ synthesized gold nanocluster-PTEN (GNC-PTEN) complexes can effectively target and realize the fluorescence imaging of the liver tumor.

RESULTS

GNC-PTEN complexes could inhibit the proliferation, invasion, and metastasis of liver cancer cells. And the results also showed that GNC-PTEN complexes could be well targeted liver tumor at 6 h and the liver tumor in mice group treated with GNC-PTEN complexes almost disappeared.

CONCLUSION

This is a simply and effectively method to realize liver cancer imaging and inhibition. This may raise the possibility for the accurate image/diagnosis and simultaneously efficient treatment of liver cancer in the relevant clinic application.

Macrophage escape by cholesterol-polyoxyethylene sorbitol oleate micelles for pulmonary delivery

Aim: Micelles are one of the most promising nanoplatforms for drug delivery, and here, cholesterol-conjugated polyoxyethylene sorbitol oleate (CPSO) micelles have been fabricated for the pulmonary delivery of paclitaxel (PTX). Materials & methods: PTX-CPSO micelles were prepared by a dialysis-ultrasonic method, and a single-factor experiment with a Box-Behnken design was conducted to optimize the formulation. Furthermore, intracellular and phagocytosis escape studies of the optimized formulation were performed on A549 and NR8383 cells. Results: The optimal micelles exhibited satisfactory encapsulation efficiency (78.48 ± 2.36%) and drug loading (17.06 ± 1.71%). In vitro studies showed enhanced CPSO micelle A549 cellular uptake and their ability to escape macrophages. Conclusion: PTX-CPSO micelles could be a promising system for pulmonary targeting by intravenous administration.

Improvement of conventional anti-cancer drugs as new tools against multidrug resistant tumors

Multidrug resistance (MDR) is the dominant cause of the failure of cancer chemotherapy. The design of antitumor drugs that are able to evade MDR is rapidly evolving, showing that this area of biomedical research attracts great interest in the scientific community. The current review explores promising recent approaches that have been developed with the aim of circumventing or overcoming MDR. Encouraging results have been obtained in the investigation of the MDR-modulating properties of various classes of natural compounds and their analogues. Inhibition of P-gp or downregulation of its expression have proven to be the main mechanisms by which MDR can be surmounted. The use of hybrid molecules that are able to simultaneously interact with two or more cancer cell targets is currently being explored as a means to circumvent drug resistance. This strategy is based on the design of hybrid compounds that are obtained either by merging the structural features of separate drugs, or by conjugating two drugs or pharmacophores via cleavable/non-cleavable linkers. The approach is highly promising due to the pharmacokinetic and pharmacodynamic advantages that can be achieved over the independent administration of the two individual components. However, it should be stressed that the task of obtaining successful multivalent drugs is a very challenging one. The conjugation of anticancer agents with nitric oxide (NO) donors has recently been developed, creating a particular class of hybrid that can combat tumor drug resistance. Appropriate NO donors have been shown to reverse drug resistance via nitration of ABC transporters and by interfering with a number of metabolic enzymes and signaling pathways. In fact, hybrid compounds that are produced by covalently attaching NO-donors and antitumor drugs have been shown to elicit a synergistic cytotoxic effect in a variety of drug resistant cancer cell lines. Another strategy to circumvent MDR is based on nanocarrier-mediated transport and the controlled release of chemotherapeutic drugs and P-gp inhibitors. Their pharmacokinetics are governed by the nanoparticle or polymer carrier and make use of the enhanced permeation and retention (EPR) effect, which can increase selective delivery to cancer cells. These systems are usually internalized by cancer cells via endocytosis and accumulate in endosomes and lysosomes, thus preventing rapid efflux. Other modalities to combat MDR are described in this review, including the pharmaco-modulation of acridine, which is a well-known scaffold in the development of bioactive compounds, the use of natural compounds as means to reverse MDR, and the conjugation of anticancer drugs with carriers that target specific tumor-cell components. Finally, the outstanding potential of in silico structure-based methods as a means to evaluate the ability of antitumor drugs to interact with drug transporters is also highlighted in this review. Structure-based design methods, which utilize 3D structural data of proteins and their complexes with ligands, are the most effective of the in silico methods available, as they provide a prediction regarding the interaction between transport proteins and their substrates and inhibitors. The recently resolved X-ray structure of human P-gp can help predict the interaction sites of designed compounds, providing insight into their binding mode and directing possible rational modifications to prevent them from becoming P-gp drug substrates. In summary, although major efforts were invested in the search for new tools to combat drug resistant tumors, they all require further implementation and methodological development. Further investigation and progress in the abovementioned strategies will provide significant advances in the rational combat against cancer MDR.

Immune Checkpoint Blockade Mediated by a Small-Molecule Nanoinhibitor Targeting the PD-1/PD-L1 Pathway Synergizes with Photodynamic Therapy to Elicit Antitumor Immunity and Antimetastatic Effects on Breast Cancer

Targeting programmed cell death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) immunologic checkpoint blockade with monoclonal antibodies has achieved recent clinical success in antitumor therapy. However, therapeutic antibodies exhibit several issues such as limited tumor penetration, immunogenicity, and costly production. Here, Bristol-Myers Squibb nanoparticles (NPs) are prepared using a reprecipitation method. The NPs have advantages including passive targeting, hydrophilic and nontoxic features, and a 100% drug loading rate. BMS-202 is a small-molecule inhibitor of the PD-1/PD-L1 interaction that is developed by BMS. Transfer of BMS-202 NPs to 4T1 tumor-bearing mice results in markedly slower tumor growth to the same degree as treatment with anti-PD-L1 monoclonal antibody (α-PD-L1). Consistently, the combination of Ce6 NPs with BMS-202 NPs or α-PD-L1 in parallel shows more efficacious antitumor and antimetastatic effects, accompanied by enhanced dendritic cell maturation and infiltration of antigen-specific T cells into the tumors. Thus, inhibition rates of primary and distant tumors reach >90%. In addition, BMS-202 NPs are able to attack spreading metastatic lung tumors and offer immune-memory protection to prevent tumor relapse. These results indicate that BMS-202 NPs possess effects similar to α-PD-L1 in the therapies of 4T1 tumors. Therefore, this work reveals the possibility of replacing the antibody used in immunotherapy for tumors with BMS-202 NPs.

The rational design of cell-penetrating peptides for application in delivery systems

Cell penetrating peptides (CPPs) play a crucial role in the transportation of bioactive molecules. Although CPPs have been used widely in various delivery systems, further applications of CPPs are hampered by several drawbacks, such as high toxicity, low delivery efficiency, proteolytic instability and poor specificity. To design CPPs with great cell-penetrating ability, physicochemical properties and safety, researchers have tried to develop new methods to overcome the defects of CPPs. Briefly, (1) the side chain of arginine containing the guanidinium group is essential for the facilitation of cellular uptake; (2) the hydrophobic counterion complex around the guanidinium-rich backbone can "coat" the highly cationic structure with lipophilic moieties and act as an activator; (3) the conformation-constrained strategy was pursued to shield the peptide, thereby impeding access of the proteolytic enzyme; (4) targeting strategies can increase cell-type specificity of CPPs. In this review, the above four aspects were discussed in detail.

Biodistribution of TAT or QLPVM coupled to receptor targeted liposomes for delivery of anticancer therapeutics to brain in vitro and in vivo

Combination therapy has emerged as an efficient way to deliver chemotherapeutics for treatment of glioblastoma. It provides collaborative approach of targeting cancer cells by acting via multiple mechanisms, thereby reducing drug resistance. However, the presence of impermeable blood brain barrier (BBB) restricts the delivery of chemotherapeutic drugs into the brain. To overcome this limitation, we designed a dual functionalized liposomes by modifying their surface with transferrin (Tf) and a cell penetrating peptide (CPP) for receptor and adsorptive mediated transcytosis, respectively. In this study, we used two different CPPs (based on physicochemical properties) and investigated the influence of insertion of CPP to Tf-liposomes on biocompatibility, cellular uptake, and transport across the BBB both in vitro and in vivo. The biodistribution profile of Tf-CPP liposomes showed more than 10 and 2.7 fold increase in doxorubicin and erlotinib accumulation in mice brain, respectively as compared to free drugs with no signs of toxicity.

Cell-penetrating peptide: a means of breaking through the physiological barriers of different tissues and organs

The selective infiltration of cell membranes and tissue barriers often blocks the entry of most active molecules. This natural defense mechanism prevents the invasion of exogenous substances and limits the therapeutic value of most available molecules. Therefore, it is particularly important to find appropriate ways of membrane translocation and therapeutic agent delivery to its target site. Cell penetrating peptides (CPPs) are a group of short peptides harnessed in this condition, possessing a significant capacity for membrane transduction and could be exploited to transfer various biologically active cargoes into the cells. Since their discovery, CPPs have been employed for delivery of a wide variety of therapeutic molecules to treat various disorders including cranial nerve involvement, ocular inflammation, myocardial ischemia, dermatosis and cancer. The promising results of CPPs-derived therapeutics in various tumor models demonstrated a potential and worthwhile scope of CPPs in chemotherapy. This review describes the detailed description of CPPs and CPPs-assisted molecular delivery against various tissues and organs disorders. An emphasis is focused on summarizing the novel insights and achievements of CPPs in surmounting the natural membrane barriers during the last 5 years.