Cell-penetrating peptides meditated encapsulation of protein therapeutics into intact red blood cells and its application

Comparison of cell delivery and cell membrane camouflaged PLGA nanoparticles in the delivery of shikonin for colorectal cancer treatment

Inspired by the "natural camouflage" strategy, cell-based biomimetic drug delivery systems (BDDS) have shown great potential in cancer therapy. Red blood cell (RBC) delivery vehicles and red blood cell membrane (RBCm)-camouflaged vehicles were commonly used strategies for drug delivery. We prepared shikonin-encapsulated PLGA nanoparticles (PLGA/SK) with different surface charges to obtain both RBC delivery and RBCm-camouflaged PLGA NPs. The physicochemical properties, in vivo circulation and antitumor effects of these biomimetic preparations were studied. Since the positive PLGA NPs may affect the morphology and function of RBCs, the biomimetic preparations prepared by the negative PLGA NPs showed better in vitro stability. However, positive PLGA NP-based biomimetic preparations exhibited longer circulation time and higher tumor region accumulation, leading to stronger anti-tumor effects. Meanwhile, the RBC delivery PLGA(+) NPs possessed better in vitro cytotoxicity, longer circulation time and higher tumor accumulation than RBCm-camouflaged PLGA(+) NPs. Collectively, RBC delivery vehicles possessed more potential than RBCm-camouflaged vehicles on drug delivery for tumor treatment, especially with positive NPs-loaded.

Engineering of Erythrocytes as Drug Carriers for Therapeutic Applications

Erythrocytes, also known as red blood cells (RBCs), have garnered considerable attention as potential carriers for drug delivery, owing to their inherent properties such as biocompatibility, biodegradability, and prolonged circulation half-life. This paper presents a comprehensive overview of the role of erythrocytes in drug delivery, elucidating recent advancements in delivering a diverse array of therapeutic agents, including small molecules, nucleic acids, antibodies, protein enzymes, and nanoparticles. Two primary strategies for encapsulating drugs within erythrocytes are systematically discussed: internal loading and surface loading. Each strategy offers distinct advantages in terms of drug stability and release kinetics. Notably, the utilization of erythrocyte membrane camouflaged nanocarriers holds promise for enhancing the biocompatibility of conventional nanoparticles and facilitating targeted drug delivery. Furthermore, the broad spectrum of biomedical applications of erythrocyte-based drug delivery systems are examined, ranging from cancer treatment to diabetes management, thrombosis prevention, and immunotherapy. This review provides a comprehensive evaluation of current technologies in erythrocyte-loaded drug delivery, highlighting the strengths, weaknesses, and future directions for advancing therapeutic interventions in various disease contexts.

Cell-mediated nanoparticle delivery systems: towards precision nanomedicine

Cell-mediated nanoparticle delivery systems (CMNDDs) utilize cells as carriers to deliver the drug-loaded nanoparticles. Unlike the traditional nanoparticle drug delivery approaches, CMNDDs take the advantages of cell characteristics, such as the homing capabilities of stem cells, inflammatory chemotaxis of neutrophils, prolonged blood circulation of red blood cells, and internalization of macrophages. Subsequently, CMNDDs can easily prolong the blood circulation, cross biological barriers, such as the blood-brain barrier and the bone marrow-blood barrier, and rapidly arrive at the diseased areas. Such advantageous properties make CMNDDs promising delivery candidates for precision targeting. In this review, we summarize the recent advances in CMNDDs fabrication and biomedical applications. Specifically, ligand-receptor interactions, non-covalent interactions, covalent interactions, and internalization are commonly applied in constructing CMNDDs in vitro. By hitchhiking cells, such as macrophages, red blood cells, monocytes, neutrophils, and platelets, nanoparticles can be internalized or attached to cells to construct CMNDDs in vivo. Then we highlight the recent application of CMNDDs in treating different diseases, such as cancer, central nervous system disorders, lung diseases, and cardiovascular diseases, with a brief discussion about challenges and future perspectives in the end.

Red blood cell-derived materials for cancer therapy: Construction, distribution, and applications

Cancer has become an increasingly important public health issue owing to its high morbidity and mortality rates. Although traditional treatment methods are relatively effective, they have limitations such as highly toxic side effects, easy drug resistance, and high individual variability. Meanwhile, emerging therapies remain limited, and their actual anti-tumor effects need to be improved. Nanotechnology has received considerable attention for its development and application. In particular, artificial nanocarriers have emerged as a crucial approach for tumor therapy. However, certain deficiencies persist, including immunogenicity, permeability, targeting, and biocompatibility. The application of erythrocyte-derived materials will help overcome the above problems and enhance therapeutic effects. Erythrocyte-derived materials can be acquired via the application of physical and chemical techniques from natural erythrocyte membranes, or through the integration of these membranes with synthetic inner core materials using cell membrane biomimetic technology. Their natural properties such as biocompatibility and long circulation time make them an ideal choice for drug delivery or nanoparticle biocoating. Thus, red blood cell-derived materials are widely used in the field of biomedicine. However, further studies are required to evaluate their efficacy, in vivo metabolism, preparation, design, and clinical translation. Based on the latest research reports, this review summarizes the biology, synthesis, characteristics, and distribution of red blood cell-derived materials. Furthermore, we provide a reference for further research and clinical transformation by comprehensively discussing the applications and technical challenges faced by red blood cell-derived materials in the treatment of malignant tumors.

Enzyme Engineering Strategies for the Bioenhancement of L-Asparaginase Used as a Biopharmaceutical

Over the past few years, there has been a surge in the industrial production of recombinant enzymes from microorganisms due to their catalytic characteristics being highly efficient, selective, and biocompatible. L-asparaginase (L-ASNase) is an enzyme belonging to the class of amidohydrolases that catalyzes the hydrolysis of L-asparagine into L-aspartic acid and ammonia. It has been widely investigated as a biologic agent for its antineoplastic properties in treating acute lymphoblastic leukemia. The demand for L-ASNase is mainly met by the production of recombinant type II L-ASNase from Escherichia coli and Erwinia chrysanthemi. However, the presence of immunogenic proteins in L-ASNase sourced from prokaryotes has been known to result in adverse reactions in patients undergoing treatment. As a result, efforts are being made to explore strategies that can help mitigate the immunogenicity of the drug. This review gives an overview of recent biotechnological breakthroughs in enzyme engineering techniques and technologies used to improve anti-leukemic L-ASNase, taking into account the pharmacological importance of L-ASNase.

Evaluation of Two Osmosis-Based Methods for the Preparation of Drug Delivery Systems Based on Red Blood Cells

Erythrocytes have been thoroughly investigated as drug delivery systems for a wide range of therapeutic molecules and using different kinds of loading methods, outstanding the osmosis-based methods as the most used ones. Most of them involve too much handling of blood components and the immediate obtention of fresh blood. Based on our group's considerable experience in dialysis-based carrier erythrocyte preparation, this study details a simple method based on hypotonic dilution and subsequent resealing that has been developed for stavudine using packed erythrocytes from a local blood bank. Properties of the obtained carrier erythrocytes were studied in comparison to those prepared by dialysis. Erythrocytes' morphology, osmotic fragility, hematological parameters, and in vitro release profiles were evaluated. Loaded erythrocytes obtained with the proposed method did not show impaired properties in comparison with those obtained with our reference method, provided that the buffer composition remained the same. In the present work, we have optimized a simplified method for erythrocytes' drug loading, which can use blood transfusion products and could be easily automatized and scalable.

Cell penetrating peptides: Highlighting points in cancer therapy

Cell-penetrating peptides (CPPs), first identified in HIV a few decades ago, deserved great attention in the last two decades; especially to support the penetration of anticancer drug means. In the drug delivery discipline, they have been involved in various approaches from mixing with hydrophobic drugs to the use of genetically conjugated proteins. The early classification as cationic and amphipathic CPPs has been extended to a few more classes such as hydrophobic and cyclic CPPs so far. Developing potential sequences utilized almost all methods of modern science: choosing high-efficiency peptides from natural protein sequences, sequence-based comparison, amino acid substitution, obtaining chemical and/or genetic conjugations, in silico approaches, in vitro analysis, animal experiments, etc. The bottleneck effect in this discipline reveals the complications that modern science faces in drug delivery research. Most CPP-based drug delivery systems (DDSs) efficiently inhibited tumor volume and weight in mice, but only in rare cases reduced their levels and continued further processes. The integration of chemical synthesis into the development of CPPs made a significant contribution and even reached the clinical stage as a diagnostic tool. But constrained efforts still face serious problems in overcoming biobarriers to reach further achievements. In this work, we reviewed the roles of CPPs in anticancer drug delivery, focusing on their amino acid composition and sequences. As the most suitable point, we relied on significant changes in tumor volume in mice resulting from CPPs. We provide a review of individual CPPs and/or their derivatives in a separate subsection.

L-Asparaginase delivery systems targeted to minimize its side-effects

L-asparaginase (L-ASP) is one of the key enzymes used in therapeutic applications, particularly to treat Acute Lymphocytic Leukemia (ALL). L-asparagine is a non-essential amino acid, which means that it can be synthesized by the body and is not required to be obtained through the diet. The synthesis of L-asparagine occurs primarily in the liver, but it also takes place in other tissues throughout the body. In contrast, leukemic cells cannot synthesize L-asparagine due the absence of L-asparagine synthetase and should obtain it from circulating sources for protein synthesis and cell division processes to ensure their vital functions. L-ASP catalyzes the deamination process of L-asparagine amino-acid into aspartic acid and ammonia, depriving leukemic cells of asparagine. This leads to decreased protein synthesis and cell division in tumor cells. However, using L-ASP has side effects, such as hypersensitivity or allergic reaction, antigenicity, short half-life, temporary blood clearance, and toxicity. L-ASP immobilization can minimize the side effects of L-ASP by stopping the immune system from attacking non-human enzymes and improving the enzyme's performance. The first strategy includes modification of enzyme structure, such as covalent binding (conjugation), adsorption to the support material and cross-linking of the enzyme. The chemical modification of residues, often nonspecific, changes the enzyme's hydrophobicity and surface charge, lowering the enzyme's activity. Also, the first strategy exposes the enzyme's surface to the environment. This eliminates its performance and does not allow targeted delivery of the enzyme. The second strategy is based on the entrapment of the enzyme inside the protecting structure or encapsulation. This strategy offers the same benefits as the first. Still, it also enables reducing toxicity, prolonging in vivo half-life, enhancing stability and activity, enables a targeted delivery and controlled release of the enzyme. Compared to the first strategy, encapsulation does not modify the chemical structure of the enzyme since L-ASP is only effective against leukemia in its native tetrameric form. This review aims to present state of the art in L-ASP formulations developed for reducing the side effects of L-ASP, focusing on describing improvements in their safety. The primary focus in the field remains to be improving the overall performance of the L-ASP formulations. Almost all encapsulation systems allow reducing immune response due to screening the enzyme from antibodies and prolonging its half-life. However, the enzyme's activity and stability depend on the encapsulation system type. Therefore, the selection of the right encapsulation system is crucial in therapy due to its effect on the performance parameters of the L-ASP. Biodegradable and biocompatible materials, such as chitosan, alginate and liposomes, mainly attract the researcher's interest in enzyme encapsulation. The research trends are also moving towards developing formulations with targeted delivery and increased selectivity.

Advances in Drug Delivery Systems Based on Red Blood Cells and Their Membrane-Derived Nanoparticles

Red blood cells (RBCs) and RBC membrane-derived nanoparticles have been historically developed as bioinspired drug delivery systems to combat the issues of premature clearance, toxicity, and immunogenicity of synthetic nanocarriers. RBC-based delivery systems possess characteristics including biocompatibility, biodegradability, and long circulation time, which make them suited for systemic administration. Therefore, they have been employed in designing optimal drug formulations in various preclinical models and clinical trials to treat a wide range of diseases. In this review, we provide an overview of the biology, synthesis, and characterization of drug delivery systems based on RBCs and their membrane including whole RBCs, RBC membrane-camouflaged nanoparticles, RBC-derived extracellular vesicles, and RBC hitchhiking. We also highlight conventional and latest engineering strategies, along with various therapeutic modalities, for enhanced precision and effectiveness of drug delivery. Additionally, we focus on the current state of RBC-based therapeutic applications and their clinical translation as drug carriers, as well as discussing opportunities and challenges associated with these systems.

Absence of terminal deoxynucleotidyl transferase expression in T-ALL/LBL accumulates chromosomal abnormalities to induce drug resistance

T-acute lymphoblastic leukemia/lymphoma (T-ALL/LBL) is a malignant neoplasm of immature lymphoblasts. Terminal deoxynucleotidyl transferase (TDT) is a template-independent DNA polymerase that plays an essential role in generating diversity for immunoglobulin genes. T-ALL/LBL patients with TDT^- have a worse prognosis. However, how TDT^- promotes the disease progression of T-ALL/LBL remains unknown. Here we analyzed the prognosis of T-ALL/LBL patients in Shanghai Children's Medical Center (SCMC) and confirmed that TDT^- patients had a higher rate of recurrence and remission failure and worse outcomes. Cellular experiments demonstrated that TDT was involved in DNA damage repair. TDT knockout delayed DNA repair, arrested the cell cycle and decreased apoptosis to induce the accumulation of chromosomal abnormalities and tolerance to abnormal karyotypes. Our study demonstrated that the poor outcomes in TDT^- T-ALL/LBL might be due to the drug resistance (VP16 and MTX) induced by chromosomal abnormalities. Our findings revealed novel functions and mechanisms of TDT in T-ALL/LBL and supported that hematopoietic stem cell transplantation (HSCT) might be a better choice for these patients.

Erythrocyte-Inspired Functional Materials for Biomedical Applications

Erythrocytes are the most abundant cells in the blood. As the results of long-term natural selection, their specific biconcave discoid morphology and cellular composition are responsible for gaining excellent biological performance. Inspired by the intrinsic features of erythrocytes, various artificial biomaterials emerge and find broad prospects in biomedical applications such as therapeutic delivery, bioimaging, and tissue engineering. Here, a comprehensive review from the fabrication to the applications of erythrocyte-inspired functional materials is given. After summarizing the biomaterials mimicking the biological functions of erythrocytes, the synthesis strategies of particles with erythrocyte-inspired morphologies are presented. The emphasis is on practical biomedical applications of these bioinspired functional materials. The perspectives for the future possibilities of the advanced erythrocyte-inspired biomaterials are also discussed. It is hoped that the summary of existing studies can inspire researchers to develop novel biomaterials; thus, accelerating the progress of these biomaterials toward clinical biomedical applications.

Cell-Based Drug Delivery Systems with Innate Homing Capability as a Novel Nanocarrier Platform

Nanoparticle-based drug delivery systems have been designed to treat various diseases. However, many problems remain, such as inadequate tumor targeting and poor therapeutic outcomes. To overcome these obstacles, cell-based drug delivery systems have been developed. Candidates for cell-mediated drug delivery include blood cells, immune cells, and stem cells with innate tumor tropism and low immunogenicity; they act as a disguise to deliver the therapeutic payload. In drug delivery systems, therapeutic agents are encapsulated intracellularly or attached to the surface of the plasma membrane and transported to the desired site. Here, we review the pros and cons of cell-based therapies and discuss their homing mechanisms in the tumor microenvironment. In addition, different strategies to load therapeutic agents inside or on the surface of circulating cells and the current applications for a wide range of disease treatments are summarized.

Red blood cell membrane nanoparticles for tumor phototherapy

Non-invasive phototherapy includes photodynamic therapy (PDT) and photothermal therapy (PTT), and has garnered special interest in anti-tumor therapy. However, traditional photosensitizers or photothermal agents are faced with major challenges, including easy recognition by immune system, rapid clearance from blood circulation, and low accumulation in target sites. Combining the characteristics of natural cell membrane with the characteristics of photosensitizer or photothermal agent is an important technology to achieve the ideal therapeutic effect of cancer. Red cell membrane (RBMs) coated can disguise phototherapy agents as endogenous substances, thus constructing a new nano bionic therapeutic platform, resisting blood clearance and prolonging circulation time. At present, a variety of phototherapy agents based on Nano-RBMs have been isolated or designed. In this review, firstly, the basic principles of Nano-RBMs and phototherapy are expounded respectively. Then, the latest progress of Nano-RBMs for PDT, PTT and PDT/PTT applications in recent five years has been introduced respectively. Finally, the problems and challenges of Nano-RBMs in the field of phototherapy are put forward.

Strategies and progresses for enhancing targeted antibiotic delivery

Antibiotic resistance is a global health issue and a potential risk for society. Antibiotics administered through conventional formulations are devoid of targeting effect and often spread to various undesired body sites, leading to sub-lethal concentrations at the site of action and thus resulting in emergence of resistance, as well as side effects. Moreover, we have a very slim antibiotic pipeline. Drug-delivery systems have been designed to control the rate, time, and site of drug release, and innovative approaches for antibiotic delivery provide a glint of hope for addressing these issues. This review elaborates different delivery strategies and approaches employed to overcome the limitations of conventional antibiotic therapy. These include antibiotic conjugates, prodrugs, and nanocarriers for local and targeted antibiotic release. In addition, a wide range of stimuli-responsive nanocarriers and biological carriers for targeted antibiotic delivery are discussed. The potential advantages and limitations of targeted antibiotic delivery strategies are described along with possible solutions to avoid these limitations. A number of antibiotics successfully delivered through these approaches with attained outcomes and potentials are reviewed.

Cell membrane-based biomimetic nanosystems for advanced drug delivery in cancer therapy: A comprehensive review

Natural types of cells display distinct characteristics with homotypic targeting and extended circulation in the blood, which are worthy of being explored as promising drug delivery systems (DDSs) for cancer therapy. To enhance their delivery efficiency, these cells can be combined with therapeutic agents and artificial nanocarriers to construct the next generation of DDSs in the form of biomimetic nanomedicines. In this review, we present the recent advances in cell membrane-based DDSs (CDDSs) and their applications for efficient cancer therapy. Different sources of cell membranes are discussed, mainly including red blood cells (RBC), leukocytes, cancer cells, stem cells and hybrid cells. Moreover, the extraction methods used for obtaining such cells and the mechanism contributing to the functional action of these biomimetic CDDSs are explained. Finally, a future perspective is proposed to highlight the limitations of CDDSs and the possible resolutions toward clinical transformation of currently developed biomimetic chemotherapies.

Efficient transdermal delivery of functional protein cargoes by a hydrophobic peptide MTD 1067

The skin has a protective barrier against the external environment, making the transdermal delivery of active macromolecules very difficult. Cell-penetrating peptides (CPPs) have been accepted as useful delivery tools owing to their high transduction efficiency and low cytotoxicity. In this study, we evaluated the hydrophobic peptide, macromolecule transduction domain 1067 (MTD 1067) as a CPP for the transdermal delivery of protein cargoes of various sizes, including growth hormone-releasing hexapeptide-6 (GHRP-6), a truncated form of insulin-like growth factor-I (des(1-3)IGF-I), and platelet-derived growth factor BB (PDGF-BB). The MTD 1067-conjugated GHRP-6 (MTD-GHRP-6) was chemically synthesized, whereas the MTD 1067-conjugated des(1-3)IGF-I and PDGF-BB proteins (MTD-des(1-3)IGF-I and MTD-PDGF-BB) were generated as recombinant proteins. All the MTD 1067-conjugated cargoes exhibited biological activities identical or improved when compared to those of the original cargoes. The analysis of confocal microscopy images showed that MTD-GHRP-6, MTD-des(1-3)IGF-I, and MTD-PDGF-BB were detected at 4.4-, 18.8-, and 32.9-times higher levels in the dermis, respectively, compared to the control group without MTD. Furthermore, the MTD 1067-conjugated cargoes did not show cytotoxicity. Altogether, our data demonstrate the potential of MTD 1067 conjugation in developing functional macromolecules for cosmetics and drugs with enhanced transdermal permeability.

Protein corona: challenges and opportunities for targeted delivery of nanomedicines

INTRODUCTION

Targeted drug delivery has been widely explored as a promising way to improve the performance of nanomedicines. However, protein corona formed on the nano-surface represents a major issue that has great impacts on the in vivo fate of targeting nanomedicines, which has been overlooked in the past. With the increasing understanding of protein corona in the recent decade, many efforts have been made to improve targeting efficacy.

AREAS COVERED

In this review, we briefly summarize insights of targeted delivery systems inspired by protein corona, and discuss the promising strategies to regulate protein corona for better targeting.

EXPERT OPINION

The interaction between nanomedicines and endogenous proteins brings great uncertainty and challenges, but it also provides great opportunities for the development of targeting nanomedicines at the same time. With increasing understanding of protein corona, the strategies to regulate protein corona pave new avenues for the development of targeting nanomedicines.

Cell-based drug delivery systems and their in vivo fate

Cell-based drug delivery systems (DDSs) have received attention recently because of their unique biological properties and self-powered functions, such as excellent biocompatibility, low immunogenicity, long circulation time, tissue-homingcharacteristics, and ability to cross biological barriers. A variety of cells, including erythrocytes, stem cells, and lymphocytes, have been explored as functional vectors for the loading and delivery of various therapeutic payloads (e.g., small-molecule and nucleic acid drugs) for subsequent disease treatment. These cell-based DDSs have their own unique in vivo fates, which are attributed to various factors, including their biological properties and functions, the loaded drugs and loading process, physiological and pathological circumstances, and the body's response to these carrier cells, which result in differences in drug delivery efficiency and therapeutic effect. In this review, we summarize the main cell-based DDSs and their biological properties and functions, applications in drug delivery and disease treatment, and in vivo fate and influencing factors. We envision that the unique biological properties, combined with continuing research, will enable development of cell-based DDSs as friendly drug vectors for the safe, effective, and even personalized treatment of diseases.

Bioinspired and Biomimetic Nanomedicines for Targeted Cancer Therapy

Undesirable side effects and multidrug resistance are the major obstacles in conventional chemotherapy towards cancers. Nanomedicines provide alternative strategies for tumor-targeted therapy due to their inherent properties, such as nanoscale size and tunable surface features. However, the applications of nanomedicines are hampered in vivo due to intrinsic disadvantages, such as poor abilities to cross biological barriers and unexpected off-target effects. Fortunately, biomimetic nanomedicines are emerging as promising therapeutics to maximize anti-tumor efficacy with minimal adverse effects due to their good biocompatibility and high accumulation abilities. These bioengineered agents incorporate both the physicochemical properties of diverse functional materials and the advantages of biological materials to achieve desired purposes, such as prolonged circulation time, specific targeting of tumor cells, and immune modulation. Among biological materials, mammalian cells (such as red blood cells, macrophages, monocytes, and neutrophils) and pathogens (such as viruses, bacteria, and fungi) are the functional components most often used to confer synthetic nanoparticles with the complex functionalities necessary for effective nano-biointeractions. In this review, we focus on recent advances in the development of bioinspired and biomimetic nanomedicines (such as mammalian cell-based drug delivery systems and pathogen-based nanoparticles) for targeted cancer therapy. We also discuss the biological influences and limitations of synthetic materials on the therapeutic effects and targeted efficacies of various nanomedicines.

Micro-patterned cell populations as advanced pharmaceutical drugs with precise functional control

Human cells are both advanced pharmaceutical drugs and 'drug deliverers'. However, functional control prior to or after cell implantation remains challenging. Micro-patterning cells through geometrically defined adhesion sites allows controlling morphogenesis, polarity, cellular mechanics, proliferation, migration, differentiation, stemness, cell-cell interactions, collective cell behavior, and likely immuno-modulatory properties. Consequently, generating micro-patterned therapeutic cells is a promising idea that has not yet been realized and few if any steps have been undertaken in this direction. This review highlights potential therapeutic applications, summarizes comprehensively the many cell functions that have been successfully controlled through micro-patterning, details the established micro-pattern designs, introduces the available fabrication technologies to the non-specialized reader, and suggests a quality evaluation score. Such a broad review is not yet available but would facilitate the manufacturing of therapeutically patterned cell populations using micro-patterned cell-instructive biomaterials for improved functional control as drug delivery systems in the context of cells as pharmaceutical products.

[Mechanisms of development of side effects and drug resistance to asparaginase and ways to overcome them]

Asparaginase is one of the most important chemotherapeutic agents against acute lymphoblastic leukemia, the most common form of blood cancer. To date, both asparaginases from E. coli and Dickeya dadantii (formerly known as Erwinia chrysanthemi), used in hematology, induce chemoresistance in cancer cells and side effects in the form of hypersensitivity of immune reactions. Leukemic cells may be resistant to asparaginase due to the increased activity of asparagine synthetase and other mechanisms associated with resistance to asparaginase. Therefore, the search for new sources of L-asparaginases with improved pharmacological properties remains a promising and prospective study. This article discusses the mechanisms of development of resistance and drug resistance to L-asparaginase, as well as possible ways to overcome them.

Recent Strategies for the Immobilization of Therapeutic Enzymes

Therapeutic enzymes play important roles in modern medicine due to their high affinity and specificity. However, it is very expensive to use them in clinical medicine because of their low stability and bioavailability. To improve the stability and effectiveness of therapeutic enzymes, immobilization techniques have been employed to enhance the applications of therapeutic enzymes in the past few years. Reported immobilization techniques include entrapment, adsorption, and covalent attachment. In addition, protein engineering is often used to improve enzyme properties; however, all methods present certain advantages and limitations. For carrier-bound immobilization, the delivery and release of the immobilized enzyme depend on the properties of the carrier and enzyme. In this review, we summarize the advantages and challenges of the current strategies developed to deliver therapeutic enzymes and provide a future perspective on the immobilization technologies used for therapeutic enzyme delivery.

Erythrocyte-enabled immunomodulation for vaccine delivery

Erythrocytes capture pathogens in circulation and present them to antigen-presenting cells (APCs) in the spleen. Senescent or apoptotic erythrocytes are physiologically eliminated by splenic APCs in a non-inflammatory manner as to not induce an immune reaction, while damaged erythrocytes tend to induce immune activation. The distinct characteristics of erythrocytes in their lifespan or different states inspire the design of targeting splenic APCs for vaccine delivery. Specifically, normal or damaged erythrocyte-driven immune targeting can induce antigen-specific immune activation, whereas senescent or apoptotic erythrocytes can be tailored to achieve antigen-specific immune tolerance. Recent studies have revealed the potential of erythrocyte-based vaccine delivery; however, there is still no in-depth review to describe the latest progress. This review summarizes the characteristics, different immune functions, and diverse vaccine delivery behaviors and biomedical applications of erythrocytes in different states. This review aims to contribute to the rational design and development of erythrocyte-based vaccine delivery systems for treating various infections, tumors, inflammatory diseases, and autoimmune diseases.

Nano-engineered immune cells as "guided missiles" for cancer therapy

Immune cells can actively regulate tumors or inflammatory sites and have good biocompatibility and safety. Currently, they are one of the most promising candidates for drug delivery systems. Moreover, immune cells can significantly extend the circulation time of nanoparticles and have broad-spectrum tumor-targeting properties. This article first introduces the immune cell types most commonly used in recent years, analyzes their advantages and disadvantages, and elucidates their application in anti-tumor therapy. Next, the various ways of loading nanoparticles on immune cells that have been used in recent years are summarized and simply divided into two categories: backpacks and Trojan horses. Finally, the two "mountains" that stand in front of us when using immune cells as cell carriers, off-target problems and effective release strategies, are discussed.

Clinical progress and advanced research of red blood cells based drug delivery system

Red blood cells (RBCs) are biocompatible carriers that can be employed to deliver different bioactive substances. In the past few decades, many strategies have been developed to encapsulate or attach drugs to RBCs. Osmotic-based encapsulation methods have been industrialized recently, and some encapsulated RBC formulations have reached the clinical stage for treating tumors and neurological diseases. Inspired by the intrinsic properties of intact RBCs, some advanced delivery strategies have also been proposed. These delivery systems combine RBCs with other novel systems to further exploit and expand the application of RBCs. This review summarizes the clinical progress of drugs encapsulated into intact RBCs, focusing on the loading and clinical trials. It also introduces the latest advanced research based on developing prospects and limitations of intact RBCs drug delivery system (DDS), hoping to provide a reference for related research fields and further application potential of intact RBCs based drug delivery system.

Multiparametric characterization of red blood cell physiology after hypotonic dialysis based drug encapsulation process

Red blood cells (RBCs) can act as carriers for therapeutic agents and can substantially improve the safety, pharmacokinetics, and pharmacodynamics of many drugs. Maintaining RBCs integrity and lifespan is important for the efficacy of RBCs as drug carrier. We investigated the impact of drug encapsulation by hypotonic dialysis on RBCs physiology and integrity. Several parameters were compared between processed RBCs loaded with l-asparaginase (“eryaspase”), processed RBCs without drug and non-processed RBCs. Processed RBCs were less hydrated and displayed a reduction of intracellular content. We observed a change in the metabolomic but not in the proteomic profile of processed RBCs. Encapsulation process caused moderate morphological changes and was accompanied by an increase of RBCs-derived Extracellular Vesicles release. Despite a decrease in deformability, processed RBCs were not mechanically retained in a spleen-mimicking device and had increased surface-to-volume ratio and osmotic resistance. Processed RBCs half-life was not significantly affected in a mouse model and our previous phase 1 clinical study showed that encapsulation of asparaginase in RBCs prolonged its in vivo half-life compared to free forms. Our study demonstrated that encapsulation by hypotonic dialysis may affect certain characteristics of RBCs but does not significantly affect the in vivo longevity of RBCs or their drug carrier function.

Purification and erythrocyte-membrane perturbing activity of a ketose-specific lectin from Moringa oleifera seeds

This study purified a hemagglutinating protein (MoL) from Moringa oleifera seed, and investigated its hemolytic activity. Molecular weight and stability of MoL were also determined. Modification of some amino acid residues was carried out and the effect on MoL hemagglutinating activity determined. Other investigated parameters are the effects of temperature, concentration, incubation period, pH, and sugars on the protein's hemagglutinating and hemolytic activities. The native and subunit molecular weights were estimated as 30 and 27.5 kDa respectively. Hemagglutinating activity of MoL was slightly inhibited by fructose and sucrose, stable at temperature up to 90°C and within pH range of 2-4. Modification of tryptophan and arginine residues resulted in partial loss of hemagglutinating activity. The hemolytic activity of MoL was concentration, temperature, pH, and time-dependent. The study concluded that MoL showed hemolytic (membrane-perturbing) activity in moderate acidic conditions. This suggests its potential exploitation in improved intracellular delivery of bioactive compounds.

Cell-mediated targeting drugs delivery systems

Drug delivery systems have shown tremendous promise to improve the diagnostic and therapeutic effects of drugs due to their special property. Targeting tissue damage, tumors, or drugs with limited toxicity at the site of infection is the goal of successful pharmaceuticals. Targeted drug delivery has become significantly important in enhancing the pharmaceutical effects of drugs and reducing their side effects of therapeutics in the treatment of various disease conditions. Unfortunately, clinical translation of these targeted drug delivery system mechanisms faces many challenges. At present, only a few targeted drug delivery systems can achieve high targeting efficiency after intravenous injection, even though numerous surface markers and targeting approaches have been developed. Thus, cell-mediated drug-delivery targeting systems have received considerable attention for their enhanced therapeutic specificity and efficacy in the treatment of the disease. This review highlights the recent advances in the design of the different types of cells that have been explored for cell-mediated drug delivery and targeting mechanisms. A better understanding of cell biology orientation and a new generation of delivery strategies that utilize these endogenous approaches are expected to provide better solutions for specific site delivery and further facilitate clinical translation.

Surface loading of nanoparticles on engineered or natural erythrocytes for prolonged circulation time: strategies and applications

Nano drug-delivery systems (DDS) may significantly improve efficiency and reduce toxicity of loaded drugs, but a few nano-DDS are highly successful in clinical use. Unprotected nanoparticles in blood flow are often quickly cleared, which could limit their circulation time and drug delivery efficiency. Elongating their blood circulation time may improve their delivery efficiency or grant them new therapeutic possibilities. Erythrocytes are abundant endogenous cells in blood and are continuously renewed, with a long life span of 100-120 days. Hence, loading nanoparticles on the surface of erythrocytes to protect the nanoparticles could be highly effective for enhancing their in vivo circulation time. One of the key questions here is how to properly attach nanoparticles on erythrocytes for different purposes and different types of nanoparticles to achieve ideal results. In this review, we describe various methods to attach nanoparticles and drugs to the erythrocyte surface, and discuss the key factors that influence the stability and circulation properties of the erythrocytes-based delivery system in vivo. These data show that using erythrocytes as a host for nanoparticles possesses great potential for further development.

Use of Protamine in Nanopharmaceuticals-A Review

Macromolecular biomolecules are currently dethroning classical small molecule therapeutics because of their improved targeting and delivery properties. Protamine-a small polycationic peptide-represents a promising candidate. In nature, it binds and protects DNA against degradation during spermatogenesis due to electrostatic interactions between the negatively charged DNA-phosphate backbone and the positively charged protamine. Researchers are mimicking this technique to develop innovative nanopharmaceutical drug delivery systems, incorporating protamine as a carrier for biologically active components such as DNA or RNA. The first part of this review highlights ongoing investigations in the field of protamine-associated nanotechnology, discussing the self-assembling manufacturing process and nanoparticle engineering. Immune-modulating properties of protamine are those that lead to the second key part, which is protamine in novel vaccine technologies. Protamine-based RNA delivery systems in vaccines (some belong to the new class of mRNA-vaccines) against infectious disease and their use in cancer treatment are reviewed, and we provide an update on the current state of latest developments with protamine as pharmaceutical excipient for vaccines.

Efficient encapsulation of functional proteins into erythrocytes by controlled shear-mediated membrane deformation

Red blood cells (RBCs) are attractive carriers of biomolecular payloads due to their biocompatibility and the ability to shelter their encapsulated cargo. Commonly employed strategies to encapsulate payloads into RBCs, such as hypotonic shock, membrane fusion or electroporation, often suffer from low throughput and unrecoverable membrane impairment. This work describes an investigation of a method to encapsulate protein payloads into RBCs by controlling membrane deformation either transiently or extendedly in a microfluidic channel. Under the optimized conditions, the loading efficiency of enhanced green fluorescent protein into mouse RBCs increased was about 2.5- and 4-fold compared to that with osmotic entrapment using transient and extended deformation, respectively. Significantly, mouse RBCs loaded with human arginase exhibit higher enzymatic activity and membrane integrity compared to their counterparts loaded by osmotic entrapment. These features together with the fact that this shear-mediated encapsulation strategy allows loading with physiological buffers highlight the key advantages of this approach compared to traditional osmotic entrapment.

Novel engineering: Biomimicking erythrocyte as a revolutionary platform for drugs and vaccines delivery

Over the years, extensive studies on erythrocytes, also known as red blood cells (RBCs), as a mechanism for drug delivery, have been explored mainly because the cell itself is the most abundant and has astonishing properties such as a long life span of 100-120 days, low immunogenicity, good biocompatibility, and flexibility. There are various types of RBC-based systems for drug delivery, including those that are genetically engineered, non-genetically engineered RBCs, as well as employing erythrocyte as nanocarriers for drug loading. Although promising, these systems are still in an early development stage. In this review, we aimed to highlight the development of biomimicking RBC-based drug and vaccine delivery systems, as well as the loading methods with illustrative examples. Drug-erythrocyte associations will also be discussed and highlighted in this review. We have highlighted the possibility of exploiting erythrocytes for the sustained delivery of drugs and vaccines, encapsulation of these biological agents within the erythrocyte or coupling to the surface of carrier erythrocytes, and provided insights on genetically- and non-genetically engineered erythrocytes-based strategies. Erythrocytes have been known as effective cellular carriers for therapeutic moieties for several years. Herein, we outline various loading methods that can be used to reap the benefits of these natural carriers. It has been shown that drugs and vaccines can be delivered via erythrocytes but it is important to select appropriate methods for increasing the drug encapsulated or conjugated on the surface of the erythrocyte membrane. The outlined examples will guide the selection of the most effective method as well as the impact of using erythrocytes as delivery systems for drugs and vaccines.

The Use of Alternative Strategies for Enhanced Nanoparticle Delivery to Solid Tumors

Nanomaterial (NM) delivery to solid tumors has been the focus of intense research for over a decade. Classically, scientists have tried to improve NM delivery by employing passive or active targeting strategies, making use of the so-called enhanced permeability and retention (EPR) effect. This phenomenon is made possible due to the leaky tumor vasculature through which NMs can leave the bloodstream, traverse through the gaps in the endothelial lining of the vessels, and enter the tumor. Recent studies have shown that despite many efforts to employ the EPR effect, this process remains very poor. Furthermore, the role of the EPR effect has been called into question, where it has been suggested that NMs enter the tumor via active mechanisms and not through the endothelial gaps. In this review, we provide a short overview of the EPR and mechanisms to enhance it, after which we focus on alternative delivery strategies that do not solely rely on EPR in itself but can offer interesting pharmacological, physical, and biological solutions for enhanced delivery. We discuss the strengths and shortcomings of these different strategies and suggest combinatorial approaches as the ideal path forward.

A cell-based drug delivery platform for treating central nervous system inflammation

Mesenchymal stem cells (MSCs) are promising candidates for the development of cell-based drug delivery systems for autoimmune inflammatory diseases, such as multiple sclerosis (MS). Here, we investigated the effect of Ro-31-8425, an ATP-competitive kinase inhibitor, on the therapeutic properties of MSCs. Upon a simple pretreatment procedure, MSCs spontaneously took up and then gradually released significant amounts of Ro-31-8425. Ro-31-8425 (free or released by MSCs) suppressed the proliferation of CD4⁺ T cells in vitro following polyclonal and antigen-specific stimulation. Systemic administration of Ro-31-8425-loaded MSCs ameliorated the clinical course of experimental autoimmune encephalomyelitis (EAE), a murine model of MS, displaying a stronger suppressive effect on EAE than control MSCs or free Ro-31-8425. Ro-31-8425-MSC administration resulted in sustained levels of Ro-31-8425 in the serum of EAE mice, modulating immune cell trafficking and the autoimmune response during EAE. Collectively, these results identify MSC-based drug delivery as a potential therapeutic strategy for the treatment of autoimmune diseases. KEY MESSAGES: MSCs can spontaneously take up the ATP-competitive kinase inhibitor Ro-31-8425. Ro-31-8425-loaded MSCs gradually release Ro-31-8425 and exhibit sustained suppression of T cells. Ro-31-8425-loaded MSCs have more sustained serum levels of Ro-31-8425 than free Ro-31-8425. Ro-31-8425-loaded MSCs are more effective than MSCs and free Ro-31-8425 for EAE therapy.

Erythrocytes as model cells for biocompatibility assessment, cytotoxicity screening of xenobiotics and drug delivery

Erythrocytes (RBCs) represent the main cell component in circulation and recently have become a topic of intensive scientific interest. The relevance of erythrocytes as a model for cytotoxicity screening of xenobiotics is under the spotlight of this review. Erythrocytes constitute a fundamental cellular model to study potential interactions with blood components of manifold novel polymer or biomaterials. Morphological changes, subsequent disruption of RBC membrane integrity, and hemolysis could be used to determine the cytotoxicity of various compounds. Erythrocytes undergo a programmed death (eryptosis) which could serve as a good model for evaluating certain mechanisms which correspond to apoptosis taking place in nucleated cells. Importantly, erythrocytes can be successfully used as a valuable cellular model in examination of oxidative stress generated by certain diseases or multiple xenobiotics since red cells are subjected to permanent oxidative stress. Additionally, the antioxidant capacity of erythrocytes, and the activity of anti-oxidative enzymes could reflect reactive oxygen species (ROS) generating properties of various substances and allow to determine their effects on tissues. The last part of this review presents the latest findings on the possible application of RBCs as drug delivery systems (DDS). In conclusion, all these findings make erythrocytes highly valuable cells for in vitro biocompatibility assessment, cytotoxicity screening of a wide variety of substances as well as drug delivery.

Deceiving SARS-CoV-2 molecular-tropism clues - A combinational contemporary strategy

Several attempts to control the dreadfulness of SARS-CoV-2 are still underway. Based on the literature evidences we have speculated a prospective contemporary remedy, which was categorized into Specificity, Remedy, and a Conveyor. In which, pros and cons were discussed and inferred the possible alternatives. (a) Specificity: Implicit to express the ACE2 receptors in conveyor cells to deceive SARS-CoV-2 from prepone targets. (b) Remedy: As depletion of pulmonary surfactants causes strong acute respiratory distress syndrome, we propose an entity of a cost-effective artificial surfactant system as a remedy to pulmonary complications. (c) Conveyor: We propose red blood cells (RBCs) as a conveyor with embedded artificial surfactant and protruding ACE2 receptors for the target-specific delivery. Overall we postulate focused insights by employing a combinational contemporary strategy to steer towards a prospective direction on combating SARS-CoV-2.

Vascular Drug Delivery Using Carrier Red Blood Cells: Focus on RBC Surface Loading and Pharmacokinetics

Red blood cells (RBC) have great potential as drug delivery systems, capable of producing unprecedented changes in pharmacokinetics, pharmacodynamics, and immunogenicity. Despite this great potential and nearly 50 years of research, it is only recently that RBC-mediated drug delivery has begun to move out of the academic lab and into industrial drug development. RBC loading with drugs can be performed in several ways-either via encapsulation within the RBC or surface coupling, and either ex vivo or in vivo-depending on the intended application. In this review, we briefly summarize currently used technologies for RBC loading/coupling with an eye on how pharmacokinetics is impacted. Additionally, we provide a detailed description of key ADME (absorption, distribution, metabolism, elimination) changes that would be expected for RBC-associated drugs and address unique features of RBC pharmacokinetics. As thorough understanding of pharmacokinetics is critical in successful translation to the clinic, we expect that this review will provide a jumping off point for further investigations into this area.

Microbial enzymes for deprivation of amino acid metabolism in malignant cells: biological strategy for cancer treatment

Amino acid deprivation therapy (AADT) is emerging as a promising strategy for the development of novel therapeutics against cancer. This biological therapy relies upon the differences in the metabolism of cancer and normal cells. The rapid growth of tumors results in decreased expression of certain enzymes leading to auxotrophy for some specific amino acids. These auxotrophic tumors are targeted by amino acid-depleting enzymes. The depletion of amino acid selectively inhibits tumor growth as the normal cells can synthesize amino acids by their usual machinery. The enzymes used in AADT are mostly obtained from microbes for their easy availability. Microbial L-asparaginase is already approved by FDA for the treatment of acute lymphoblastic leukemia. Arginine deiminase and methionase are under clinical trials and the therapeutic potential of lysine oxidase, glutaminase and phenylalanine ammonia lyase is also being explored. The present review provides an overview of microbial amino acid depriving enzymes. Various attributes of these enzymes like structure, mode of action, production, formulations, and targeted cancers are discussed. The challenges faced and the combat strategies to establish AADT in standard cancer armamentarium are also reviewed.Key Points • Amino acid deprivation therapy is a potential therapy for auxotrophic tumors. • Microbial enzymes are used due to their ease of manipulation and high productivity. • Enzyme properties are improved by PEGylation, encapsulation, and genetic engineering. • AADT can be employed as combinational therapy for better containment of cancer.

Using a Membrane-Penetrating-Peptide to Anchor Ligands in the Liposome Membrane Facilitates Targeted Drug Delivery

Antimicrobial peptides (AMPs) are typical cell penetrating peptides (CPPs) that intercalate into biomembranes and exhibit broad activities. We designed a triple fusion protein consisting of an AMP, Ib-AMP4 at the N-terminus, a fluorescent GFP probe in the center, and the tumor-targeting peptide P1c at the other terminus. After purification from E. coli, the interaction between the Ib-AMP4-GFP-P1c fusion protein (IGP) and the lipid membrane was characterized. Experiments using isothermal titration calorimetry (ITC) and quartz crystal microbalance with dissipation (QCM-D) demonstrated that IGP proteins spontaneously bound the lipid bilayer with a maximal molar ratio of 1:52 (protein:lipid). Furthermore, transmission electron microscopy (TEM) confirmed that the IGP protein was present in the liposome membrane. After decoration with IGP proteins, the DOPC:DOPG liposomes were applied to cancer cells. Microscopy and flow cytometry reveal that the decorated liposomes selectively bound integrin αvβ3-positive A549 cells. In addition, compared with the common chemical conjugation method, the reported method seemed to be superior in certain aspects, such as simple sample preparation and cost-effectiveness. Next, the IGP protein was applied to decorate red blood cell (RBC) liposomes for targeted delivery in both in vitro and in vivo applications. The IGP-decorated RBC liposomes preferentially targeted integrin αvβ3 expressing A549 cancer cells. The in vivo imaging showed that IGP-decorated RBC liposomes were concentrated in tumor tissue and were primarily metabolized by the liver and kidney.

Cell penetrating peptides: the potent multi-cargo intracellular carriers

Introduction: Cell penetrating peptides (CPPs) known as protein translocation domains (PTD), membrane translocating sequences (MTS), or Trojan peptides (TP) are able to cross biological membranes without clear toxicity using different mechanisms, and facilitate the intracellular delivery of a variety of bioactive cargos. CPPs could overcome some limitations of drug delivery and combat resistant strains against a broad range of diseases. Despite delivery of different therapeutic molecules by CPPs, they lack cell specificity and have a short duration of action. These limitations led to design of combined cargo delivery systems and subsequently improvement of their clinical applications. Areas covered: This review covers all our studies and other researchers in different aspects of CPPs such as classification, uptake mechanisms, and biomedical applications. Expert opinion: Due to low cytotoxicity of CPPs as compared to other carriers and final degradation to amino acids, they are suitable for preclinical and clinical studies. Generally, the efficiency of CPPs was suitable to penetrate the cell membrane and deliver different cargos to specific intracellular sites. However, no CPP-based therapeutic approach has approved by FDA, yet; because there are some disadvantages for CPPs including short half-life in blood, and nonspecific CPP-mediated delivery to normal tissue. Thus, some methods were used to develop the functions of CPPs in vitro and in vivo including the augmentation of cell specificity by activatable CPPs, specific transport into cell organelles by insertion of corresponding localization sequences, incorporation of CPPs into multifunctional dendrimeric or liposomal nanocarriers to improve selectivity and efficiency especially in tumor cells.

Improved Protein Toxin Delivery Based on ATTEMPTS Systems

BACKGROUND

Ribosome-inactivating proteins (RIPs) are wildly found in multiple species of plants, bacteria and fungi. As a special family of protein toxins, RIPs can inhibit protein synthesis and induce cell death via inactivating ribosome in eukaryotic cells. Thus, RIPs have been applied for anti-tumor therapy in the past two decades. However, because of poor cell permeability, nonselective mode of action for tumor cells, poor pharmacokinetic profiles and immunogenicity, their clinical application has been severely constrained. As an effort to overcome these obstacles, tumor-specific monoclonal antibodies (mAb) have been conjugated to RIPs (forming so called "immunotoxins") specifically to increase their cytotoxicity and provide tumor targeting. Nevertheless, immunotoxins yet have not fully resolved all the issues and critical challenges still remain, such as immunogenicity and inability to penetrate into the deep site of tumor.

OBJECTIVE

To overcome the constrain of immunotoxins, the novel cell-penetrating peptide (CPP)- modified ATTEMPTS systems based on combination of CPP-mediated penetration and antibodymediated tumor targeting, with triggerable drug release function, were developed to achieve effective and safe delivery of protein toxin.

RESULTS

The CPP-modified ATTEMPTS systems showed effective protamine-triggered CPP-toxin release and thus enhanced CPP-mediated cellular uptake and cytotoxicity. It also showed antibodymediated in vivo tumor targeting and significantly increased in vivo tumor growth suppression with limited systematic toxicity.

CONCLUSION

The CPP-modified ATTEMPTS systems were developed and demonstrated as a proof-ofconcept for CPP-based protein toxin delivery with triggerable antibody targeting to improve the druggability of protein toxin drugs. The systems showed the potential application of protein toxin clinical translation in anticancer treatment.

Red blood cells as an efficient in vitro model for evaluating the efficacy of metallic nanoparticles

Blood and the linings of blood vessels may be regarded as a fifth tissue type. The human body contains 5 × 10⁹ red blood cells (RBCs) per ml, a total of 2.5 × 10¹³ cells in the 5 l of blood present in the body. With an average lifetime of 125 days, human RBCs are destroyed by leukocytes in the spleen and liver. Nowadays red blood cells are extensively used to study various metabolic functions. Nanoparticles (NP) are being widely accepted for drug delivery system. This review summarizes the red blood cells, NPs and their characteristics on the basis of the RBC components along with drug delivery systems through RBCs. Further, we also discussed that how erythrocytes can be used as an efficient in vitro model for evaluating the efficacy of various nanocomposite materials.

Tunneling Nanotubular Expressways for Ultrafast and Accurate M1 Macrophage Delivery of Anticancer Drugs to Metastatic Ovarian Carcinoma

It is extremely difficult for cancer chemotherapy to control the peritoneal metastasis of advanced ovarian carcinoma given its inability to target disseminated tumors and the severe toxic side effects on healthy organs. Here, we report antitumor M1 macrophages developed as live-cell carriers that deliver anticancer drugs for the treatment of the metastatic ovarian carcinoma. Engineered doxorubicin-loaded M1 macrophages (M1-Dox) significantly enhanced tumor tropism by upregulation of CCR2 and CCR4 compared with their parent cells. Meanwhile, M1-Dox inhibited doxorubicin-induced tumor invasion, whereas commercial Lipo-Dox did not limit these side effects. Importantly, our data uncovered a drug delivery mechanism by which M1-Dox transferred drug cargoes into tumor cells  via a tunneling nanotube pathway. The tunneling nanotube network acted as a transportation expressway for ultrafast drug delivery of M1-Dox, leading to efficient ovarian carcinoma cell death. Furthermore, genetic, pharmacological, and physical perturbations of these tunneling nanotubes obviously decreased drug transfer of M1-Dox, which further validated the evident correlation between drug delivery of M1-Dox and tunneling nanotubes. Finally, in peritoneal metastatic ovarian carcinoma-burdened mice, M1-Dox specifically penetrated into and accumulated deep within disseminated neoplastic lesions compared with commercial Lipo-Dox, resulting in reducing metastatic tumors to a nearly undetectable level and significantly increasing overall survival. Overall, the strategy of engineered macrophages for ultrafast and accurate drug delivery via the tunneling nanotubular expressway potentially revolutionizes the treatment of metastatic ovarian carcinoma.

Isolation, Purification, Characterisation and Application of L-ASNase: A Review

BACKGROUND

L-ASNase (L-asparagine aminohydrolase EC 3.5.1.1) is used for the conversion of L-asparagine to L-aspartic acid and ammonia and also it was found as an agent of chemotherapeutic property according to recent patents. It is known as an anti-cancer agent and recently it has received an immense attention. Various microorganisms have the ability to secrete the L-ASNase. It is famous world-wide as anti-tumor medicine for acute lymphoblastic leukemia and lymphosarcoma. L-ASNase helps in deamination of Asparagine and Glutamine.

SOURCE

L-ASNase mainly found in two bacterial sources; Escherichia coli and Erwinia carotovora. Isolation from plants: Endophytes were also a great source of L-ASNase. It was isolated from four types of plants named as; C. citratus, O. diffusa, M. koengii, and also P. bleo.

APPLICATIONS

L-ASNase is used as a potential anti-tumor medicine. It plays a very much essential role for the growth of tumor cells. Tumor cells require a lot of asparagine for their growth. But ASNase converts to aspartate and ammonia from asparagine. So the tumor cell does not proliferate and fails to survive. The L-ASNase is used as the medicine for the major type of cancer like acute lymphocytic leukemia (ALL), brain. It also used as a medicine for central nervous system (CNS) tumors, and also for neuroblastoma. Two types of L-ASNase have been found.

CONCLUSION

L-ASNase becomes a powerful anti-tumor medicine and researchers should develop a potent strain of asparaginase which can produce asparaginase in the industrial level. It is also used in the pharmaceutical industry and food industry on a broader scale.

Autologous Red Blood Cell Delivery of Betamethasone Phosphate Sodium for Long Anti-Inflammation

Although glucocorticoids are highly effective in treating various types of inflammation such as skin disease, rheumatic disease, and allergic disease, their application have been seriously limited for their high incidence of side effects, particularly in long term treatment. To improve efficacy and reduce side effects, we encapsulated betamethasone phosphate (BSP) into biocompatible red blood cells (RBCs) and explored its long acting-effect. BSP was loaded into rat autologous erythrocytes by hypotonic preswelling method, and the loading amount was about 2.5 mg/mL cells. In vitro, BSP loaded RBCs (BSP-RBCs) presented similar morphology, osmotic fragility to native RBCs (NRBCs). After the loading process, the loaded cells can maintain around 70% of Na⁺/K⁺-ATPase activity of natural cells. In vivo, a series of tests including survival, pharmacokinetics, and anti-inflammatory effect were carried out to examine the long-acting effect of BSP-RBCs. The results shown that the loaded cells could circulate in plasma for over nine days, the release of BSP can last for over seven days and the anti-inflammatory effect can still be observed on day 5 after injection. Totally, BSP-loaded autologous erythrocytes seem to be a promising sustained releasing delivery system with long anti-inflammatory effect.

Granzyme B-loaded, cell-selective penetrating and reduction-responsive polymersomes effectively inhibit progression of orthotopic human lung tumor in vivo

The clinical use of protein therapeutics with intracellular targets is hampered by its in vivo fragility and low cell permeability. Here, we report that cell-selective penetrating and reduction-responsive polymersomes (CPRPs) mediate high-efficiency targeted delivery of granzyme B (GrB) to orthotopic human lung tumor in vivo. Model protein studies using FITC-labeled cytochrome C (FITC-CC) revealed efficient and high protein loading up to 17.2 wt% for CPRPs. FITC-CC-loaded CPRPs exhibited a small size of 82-90 nm, reduction-responsive protein release, as well as greatly enhanced internalization and cytoplasmic protein release in A549 lung cancer cells compared with the non-targeted FITC-CC-loaded RPs control. GrB-loaded CPRPs showed a high potency toward A549 lung cancer cells with a half maximal inhibitory concentration (IC₅₀) of 20.7 nM. Under the same condition, free GrB was essentially non-toxic. Importantly, installing cell-selective penetrating peptide did not alter the circulation time but did enhance tumor accumulation of RPs. Orthotopic A549-Luc lung tumor-bearing nude mice administered with GrB-loaded CPRPs at a dosage of 2.88 nmol GrB equiv./kg showed complete tumor growth inhibition with little body weight loss throughout the treatment period, resulting in significantly improved survival rate over the non-targeted and non-treated controls. These cell-selective penetrating and reduction-responsive polymersomes provide a targeted protein therapy for cancers.