Highly compacted DNA nanoparticles with low MW PEG coatings: in vitro, ex vivo and in vivo evaluation

Elucidation of lipid nanoparticle surface structure in mRNA vaccines

Lipid nanoparticles (LNPs) have been used as a carrier for messenger RNA (mRNA) vaccines. Surface properties of LNPs are important to the stability and function of mRNA vaccines. Polyethylene-glycol (PEG) is a functional lipid at the surface of LNPs that improves colloidal stability, increases circulation time, and impacts cellular uptake. In this study, we explore in-depth lipid composition at the surface of mRNA-LNPs using high-field nuclear magnetic resonance (NMR) spectroscopy. Our results provide a unique surface lipid profile of intact LNPs identifying PEG chains and partial ionizable lipids are present with quantification capability. The surface PEG density is determined to reveal the brush-like conformation on the surface of mRNA-LNPs. Furthermore, we implement a diffusion NMR strategy for routine testing of formulated drug products during drug development. Comparative NMR analysis of different vaccine preparations and stability samples provides a global view of the mRNA-LNP surface structure for enhanced product knowledge.

Advanced approaches to overcome biological barriers in respiratory and systemic routes of administration for enhanced nucleic acid delivery to the lung

INTRODUCTION

Numerous delivery strategies, primarily novel nucleic acid delivery carriers, have been developed and explored to enable therapeutically relevant lung gene therapy. However, its clinical translation is yet to be achieved despite over 30 years of efforts, which is attributed to the inability to overcome a series of biological barriers that hamper efficient nucleic acid transfer to target cells in the lung.

AREAS COVERED

This review is initiated with the fundamentals of nucleic acid therapy and a brief overview of previous and ongoing efforts on clinical translation of lung gene therapy. We then walk through the nature of biological barriers encountered by nucleic acid carriers administered via respiratory and/or systemic routes. Finally, we introduce advanced strategies developed to overcome those barriers to achieve therapeutically relevant nucleic acid delivery efficiency in the lung.

EXPERT OPINION

We are now stepping close to the clinical translation of lung gene therapy, thanks to the discovery of novel delivery strategies that overcome biological barriers via comprehensive preclinical studies. However, preclinical findings should be cautiously interpreted and validated to ultimately realize meaningful therapeutic outcomes with newly developed delivery strategies in humans. In particular, individual strategies should be selected, tailored, and implemented in a manner directly relevant to specific therapeutic applications and goals.

Airway mucus in pulmonary diseases: Muco-adhesive and muco-penetrating particles to overcome the airway mucus barriers

Airway mucus is a complex viscoelastic gel that provides a defensive physical barrier and shields the airway epithelium by trapping inhaled foreign pathogens and facilitating their removal via mucociliary clearance (MCC). In patients with respiratory diseases, such as chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), non-CF bronchiectasis, and asthma, an increase in crosslinking and physical entanglement of mucin polymers as well as mucus dehydration often alters and typically reduces mucus mesh network pore size, which reduces neutrophil migration, decreases pathogen capture, sustains bacterial infection, and accelerates lung function decline. Conventional aerosol particles containing hydrophobic drugs are rapidly captured and removed by MCC. Therefore, it is critical to design aerosol delivery systems with the appropriate size and surface chemistry that can improve drug retention and absorption with the goal of increased efficacy. Biodegradable muco-adhesive particles (MAPs) and muco-penetrating particles (MPPs) have been engineered to achieve effective pulmonary delivery and extend drug residence time in the lungs. MAPs can be used to target mucus as they get trapped in airway mucus by steric obstruction and/or adhesion. MPPs avoid muco-adhesion and are designed to have a particle size smaller than the mucus network, enhancing lung retention of particles as well as transport to the respiratory epithelial layer and drug absorption. In this review, we aim to provide insight into the composition of airway mucus, rheological characteristics of airway mucus in healthy and diseased subjects, the most recent techniques to study the flow dynamics and particle diffusion in airway mucus (in particular, multiple particle tracking, MPT), and the advancements in engineering MPPs that have contributed to improved airway mucus penetration, lung distribution, and retention.

Site-Specific Polyplex on CCR7 Down-Regulation and T Cell Elevation for Lymphatic Metastasis Blocking on Breast Cancer

Tumor metastasis contributes to high cancer mortality. Tumor cells in lymph nodes (LNs) are difficult to eliminate but underlie uncontrollable systemic metastasis. The CC chemokine receptor 7 (CCR7) is overexpressed in tumor cells and interacts with CC chemokine ligand 21 (CCL21) secreted from LNs, potentiating their lymphatic migration. Here, a site-specific polyplex is developed to block the CCR7-CCL21 signal and kill tumor cells toward LNs, greatly limiting their lymphatic infiltration. A CCR7-targeting small interfering RNA (siCCR7) is condensed by mPEG-poly-(lysine) with chlorin e6 (Ce6) modification (PPLC) to form PPLC/siCCR7. The knockdown of CCR7 by siCCR7 in tumor cells significantly reduced their response on CCL21 and LN tropism. Additionally, photodynamic therapy-mediated immune activation precisely targets and kills tumor cells released from the primary foci before they reaches the LNs, reducing the number of tumor cells entering the LNs. Consequently, the PPLC/siCCR7 polyplexes inhibited up to 92% of lung metastasis in 4T1 tumor bearing mice and reduced tumor cell migration to LNs by up to 80%. This site-specific strategy optimized anti-metastasis efficacy and promotes the clinical translational development of anti-metastatic therapy.

Pulmonary delivery nanomedicines towards circumventing physiological barriers: Strategies and characterization approaches

Pulmonary delivery of nanomedicines is very promising in lung local disease treatments whereas several physiological barriers limit its application via the interaction with inhaled nanomedicines, namely bio-nano interactions. These bio-nano interactions may affect the pulmonary fate of nanomedicines and impede the distribution of nanomedicines in its targeted region, and subsequently undermine the therapeutic efficacy. Pulmonary diseases are under worse scenarios as the altered physiological barriers generally induce stronger bio-nano interactions. To mitigate the bio-nano interactions and regulate the pulmonary fate of nanomedicines, a number of manipulating strategies were established based on size control, surface modification, charge tuning and co-delivery of mucolytic agents. Visualized and non-visualized characterizations can be employed to validate the robustness of the proposed strategies. This review provides a guiding overview of the physiological barriers affecting the in vivo fate of inhaled nanomedicines, the manipulating strategies, and the validation methods, which will assist with the rational design and application of pulmonary nanomedicine.

Polymeric Delivery of Therapeutic Nucleic Acids

The advent of genome editing has transformed the therapeutic landscape for several debilitating diseases, and the clinical outlook for gene therapeutics has never been more promising. The therapeutic potential of nucleic acids has been limited by a reliance on engineered viral vectors for delivery. Chemically defined polymers can remediate technological, regulatory, and clinical challenges associated with viral modes of gene delivery. Because of their scalability, versatility, and exquisite tunability, polymers are ideal biomaterial platforms for delivering nucleic acid payloads efficiently while minimizing immune response and cellular toxicity. While polymeric gene delivery has progressed significantly in the past four decades, clinical translation of polymeric vehicles faces several formidable challenges. The aim of our Account is to illustrate diverse concepts in designing polymeric vectors towards meeting therapeutic goals of in vivo and ex vivo gene therapy. Here, we highlight several classes of polymers employed in gene delivery and summarize the recent work on understanding the contributions of chemical and architectural design parameters. We touch upon characterization methods used to visualize and understand events transpiring at the interfaces between polymer, nucleic acids, and the physiological environment. We conclude that interdisciplinary approaches and methodologies motivated by fundamental questions are key to designing high-performing polymeric vehicles for gene therapy.

Inhalable PLGA microspheres: Tunable lung retention and systemic exposure via polyethylene glycol modification

Polyethylene glycol (PEG) modification is one of the promising approaches to overcome both mucus and alveolar macrophage uptake barriers in the deep lung for sustained therapy of pulmonary diseases such as asthma. To investigate the feasibility of using PEG-modified microspheres to bypass both barriers, we prepared a collection of polyethylene glycol-distearoyl glycero-phosphoethanolamine (PEG-DSPE)-modified poly (lactide-co-glycolide) (PLGA) microspheres bearing specific PEG molecular weights (0.75, 2, 5, and 10 kDa) and PEG-DSPE/PLGA molar ratios (0.25:1 and 1:1). Drug release, mucus penetration, and macrophage uptake were evaluated in vitro, and the corresponding in vivo activities of microspheres in rats were investigated. It was found that the PEG₂₀₀₀-DSPE/PLGA 1:1 group showed enhanced mucus permeability and reduced macrophage uptake in vitro compared to the PEG₂₀₀₀-DSPE/PLGA 0.25:1 group. At high PEG molar ratios, only the PEG 2000-based group showed significantly prolonged lung retention in vivo compared to the control group. The systemic exposure of the PEG₂₀₀₀-DSPE/PLGA 1:1 group was significantly lower than that of the PEG₂₀₀₀-DSPE/PLGA 0.25:1 group (39% of AUC reduction). Additionally, when using the same molar ratio of 1:1, the PEG 2000 group significantly lowered the systemic drug exposure compared to that of the PEG 5000 and 10000 groups (48% and 33% of AUC reduction, respectively), thus making it a promising sustained lung delivery candidate for pulmonary disease treatment.

Advanced materials for drug delivery across mucosal barriers

Mucus is a viscoelastic gel that traps pathogens and other foreign particles to limit their penetration into the underlying epithelium. Dosage forms containing particle-based drug delivery systems are trapped in mucosal layers and will be removed by mucus turnover. Mucoadhesion avoids premature wash-off and prolongs the residence time of drugs on mucus. Moreover, mucus penetration is essential for molecules to access the underlying epithelial tissues. Various strategies have been investigated to achieve mucoadhesion and mucus penetration of drug carriers. Innovations in materials used for the construction of drug-carrier systems allowed the development of different mucoadhesion and mucus penetration delivery systems. Over the last decade, advances in the field of materials chemistry, with a focus on biocompatibility, have led to the expansion of the pool of materials available for drug delivery applications. The choice of materials in mucosal delivery is generally dependent on the intended therapeutic target and nature of the mucosa at the site of absorption. This review presents an up-to-date account of materials including synthesis, physical and chemical modifications of mucoadhesive materials, nanocarriers, viral mimics used for the construction of mucosal drug delivery systems.

On Complex Coacervate Core Micelles: Structure-Function Perspectives

The co-assembly of ionic-neutral block copolymers with oppositely charged species produces nanometric colloidal complexes, known, among other names, as complex coacervates core micelles (C3Ms). C3Ms are of widespread interest in nanomedicine for controlled delivery and release, whilst research activity into other application areas, such as gelation, catalysis, nanoparticle synthesis, and sensing, is increasing. In this review, we discuss recent studies on the functional roles that C3Ms can fulfil in these and other fields, focusing on emerging structure-function relations and remaining knowledge gaps.

Structural Polymorphism of Single pDNA Condensates Elicited by Cationic Block Polyelectrolytes

DNA folding is a core phenomenon in genome packaging within a nucleus. Such a phenomenon is induced by polyelectrolyte complexation between anionic DNA and cationic proteins of histones. In this regard, complexes formed between DNA and cationic polyelectrolytes have been investigated as models to gain insight into genome packaging. Upon complexation, DNA undergoes folding to reduce its occupied volume, which often results in multi-complex associated aggregates. However, when cationic copolymers comprising a polycation block and a neutral hydrophilic polymer block are used instead, DNA undergoes folding as a single molecule within a spontaneously formed polyplex micelle (PM), thereby allowing the observation of the higher-order structures that DNA forms. The DNA complex forms polymorphic structures, including globular, rod-shaped, and ring-shaped (toroidal) structures. This review focuses on the polymorphism of DNA, particularly, to elucidate when, how, and why DNA organizes into these structures with cationic copolymers. The interactions between DNA and the copolymers, and the specific nature of DNA in rigidity; i.e., rigid but foldable, play significant roles in the observed polymorphism. Moreover, PMs serve as potential gene vectors for systemic application. The significance of the controlled DNA folding for such an application is addressed briefly in the last part.

Immunology-Guided Biomaterial Design for Mucosal Cancer Vaccines

Cancer of mucosal tissues is a major cause of worldwide mortality for which only palliative treatments are available for patients with late-stage disease. Engineered cancer vaccines offer a promising approach for inducing antitumor immunity. The route of vaccination plays a major role in dictating the migratory pattern of lymphocytes, and thus vaccine efficacy in mucosal tissues. Parenteral immunization, specifically subcutaneous and intramuscular, is the most common vaccination route. However, this induces marginal mucosal protection in the absence of tissue-specific imprinting signals. To circumvent this, the mucosal route can be utilized, however degradative mucosal barriers must be overcome. Hence, vaccine administration route and selection of materials able to surmount transport barriers are important considerations in mucosal cancer vaccine design. Here, an overview of mucosal immunity in the context of cancer and mucosal cancer clinical trials is provided. Key considerations are described regarding the design of biomaterial-based vaccines that will afford antitumor immune protection at mucosal surfaces, despite limited knowledge surrounding mucosal vaccination, particularly aided by biomaterials and mechanistic immune-material interactions. Finally, an outlook is given of how future biomaterial-based mucosal cancer vaccines will be shaped by new discoveries in mucosal vaccinology, tumor immunology, immuno-therapeutic screens, and material-immune system interplay.

Interface-Enrichment-Induced Instability and Drug-Loading-Enhanced Stability in Inhalable Delivery of Supramolecular Filaments

Filamentous microorganisms traveling in aerosol particles display enhanced deposition and retention in the lungs. Inspired by this shape-related biological effect, we report here on the use of supramolecular filaments as potential inhalable drug carriers within aerosols via jet nebulization. We found that the peptide design and supramolecular stability play a crucial role in the interfacial stability and aerosolization properties of the supramolecular filaments. Monomeric units with a positively charged C-terminus produced filaments with reduced aerosol stability, promoting morphological changes after nebulization. Conversely, having a neutral or negatively charged terminus yielded filaments with enhanced stability, where supramolecular integrity is maintained with only reduced length. Our results suggest that molecular enrichment at the air-liquid interface during nebulization is the primary factor to deplete the monomeric peptide amphiphiles in solution, accounting for the observed morphological disruption/transitions. Importantly, encapsulation of drugs and dyes within filaments notably stabilize their supramolecular structure during nebulization, and the loaded filaments exhibit a linear release profile from a nebulizer device. We envision the use of this supramolecular carrier system as an effective platform for the inhalation-based treatment of many lung diseases.

Inhalable nanotherapeutics to improve treatment efficacy for common lung diseases

Respiratory illnesses are prevalent around the world, and inhalation-based therapies provide an attractive, noninvasive means of directly delivering therapeutic agents to their site of action to improve treatment efficacy and limit adverse systemic side effects. Recent trends in medicine and nanoscience have prompted the development of inhalable nanomedicines to further enhance effectiveness, patient compliance, and quality of life for people suffering from lung cancer, chronic pulmonary diseases, and tuberculosis. Herein, we discuss recent advancements in the development of inhalable nanomaterial-based drug delivery systems and analyze several representative systems to illustrate their key design principles that can translate to improved therapeutic efficacy for prevalent respiratory diseases. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Respiratory Disease.

Current Practices and Potential Nanotechnology Perspectives for Pain Related to Cystic Fibrosis

Pain is a complex, multidimensional process that negatively affects physical and mental functioning, clinical outcomes, quality of life, and productivity for cystic fibrosis (CF) patients. CF is an inherited multi-system disease that requires a complete approach in order to evaluate, monitor and treat patients. The landscape in CF care has changed significantly, with currently more adult patients than children worldwide. Despite the great advances in supportive care and in our understanding regarding its pathophysiology, there are still numerous aspects of CF pain that are not fully explained. This review aims to provide a critical overview of CF pain research that focuses on pain assessment, prevalence, characteristics, clinical association and the impact of pain in children and adults, along with innovative nanotechnology perspectives for CF management. Specifically, the paper evaluates the pain symptoms associated with CF and examines the relationship between pain symptoms and disease severity. The particularities of gastrointestinal, abdominal, musculoskeletal, pulmonary and chest pain, as well as pain associated with medical procedures are investigated in patients with CF. Disease-related pain is common for patients with CF, suggesting that pain assessment should be a routine part of their clinical care. A summary of the use of nanotechnology in CF and CF-related pain is also given. Further research is clearly needed to better understand the sources of pain and how to improve patients’ quality of life.

Vaginal delivery of mucus-penetrating organic nanoparticles for photothermal therapy against cervical intraepithelial neoplasia in mice

Photosensitizer-based photothermal therapy (PTT) may be a good choice for the treatment of severe cervical intraepithelial neoplasia (CIN) compared with conventional thermal ablation.

Lipid Nanoparticle-Delivered Chemically Modified mRNA Restores Chloride Secretion in Cystic Fibrosis

The promise of gene therapy for the treatment of cystic fibrosis has yet to be fully clinically realized despite years of effort toward correcting the underlying genetic defect in the cystic fibrosis transmembrane conductance regulator (CFTR). mRNA therapy via nanoparticle delivery represents a powerful technology for the transfer of genetic material to cells with large, widespread populations, such as airway epithelia. We deployed a clinically relevant lipid-based nanoparticle (LNP) for packaging and delivery of large chemically modified CFTR mRNA (cmCFTR) to patient-derived bronchial epithelial cells, resulting in an increase in membrane-localized CFTR and rescue of its primary function as a chloride channel. Furthermore, nasal application of LNP-cmCFTR restored CFTR-mediated chloride secretion to conductive airway epithelia in CFTR knockout mice for at least 14 days. On day 3 post-transfection, CFTR activity peaked, recovering up to 55% of the net chloride efflux characteristic of healthy mice. This magnitude of response is superior to liposomal CFTR DNA delivery and is comparable with outcomes observed in the currently approved drug ivacaftor. LNP-cmRNA-based systems represent a powerful platform technology for correction of cystic fibrosis and other monogenic disorders.

Mannose and Mannose-6-Phosphate Receptor-Targeted Drug Delivery Systems and Their Application in Cancer Therapy

In order to overcome the main disadvantages of conventional cancer therapies, which prove to be inadequate because of their lack of selectivity, the development of targeted delivery systems is one of the main focuses in anticancer research. It is repeatedly shown that decorating the surface of nanocarriers with high-affinity targeting ligands, such as peptides or small molecules, is an effective way to selectively deliver therapeutics by enhancing their specific cellular uptake via the binding between a specific receptor and the nanosystems. Nowadays, the need of finding new potential biological targets with a high endocytic efficiency as well as a low tendency to mutate is urgent and, in this context, mannose and mannose-6-phosphate receptors appear promising to target anticancer drugs to cells where their expression is upregulated. Moreover, they open the path to encouraging applications in immune-based and gene therapies as well as in theragnostic purposes. In this work, the potential of mannose- and mannose-6-phosphate-targeted delivery systems in cancer therapy is discussed, emphasizing their broad application both in direct treatments against cancer cells with conventional chemotherapeutics or by gene therapy and also their encouraging capabilities in immunotherapy and diagnostics purposes.

Block Copolymer Micelles in Nanomedicine Applications

Polymeric micelles are demonstrating high potential as nanomedicines capable of controlling the distribution and function of loaded bioactive agents in the body, effectively overcoming biological barriers, and various formulations are engaged in intensive preclinical and clinical testing. This Review focuses on polymeric micelles assembled through multimolecular interactions between block copolymers and the loaded drugs, proteins, or nucleic acids as translationable nanomedicines. The aspects involved in the design of successful micellar carriers are described in detail on the basis of the type of polymer/payload interaction, as well as the interplay of micelles with the biological interface, emphasizing on the chemistry and engineering of the block copolymers. By shaping these features, polymeric micelles have been propitious for delivering a wide range of therapeutics through effective sensing of targets in the body and adjustment of their properties in response to particular stimuli, modulating the activity of the loaded drugs at the targeted sites, even at the subcellular level. Finally, the future perspectives and imminent challenges for polymeric micelles as nanomedicines are discussed, anticipating to spur further innovations.

Enhanced uptake in 2D- and 3D- lung cancer cell models of redox responsive PEGylated nanoparticles with sensitivity to reducing extra- and intracellular environments

In the treatment of lung cancer, there is an urgent need of innovative medicines to optimize pharmacological responses of conventional chemotherapeutics while attenuating side effects. Here, we have exploited some relatively unexplored subtle differences in reduction potential, associated with cancer cell microenvironments in addition to the well-known changes in intracellular redox environment. We report the synthesis and application of novel redox-responsive PLGA (poly(lactic-co-glycolic acid)) -PEG (polyethylene glycol) nanoparticles (RR-NPs) programmed to change surface properties when entering tumor microenvironments, thus enhancing cell internalization of the particles and their drug cargo. The new co-polymers, in which PEG and PLGA were linked by 'anchiomeric effector' dithiylethanoate esters, were synthesized by a combination of ring-opening polymerization and Michael addition reactions and employed to prepare NPs. Non redox-responsive nanoparticles (nRR-NPs) based on related PLGA-PEG copolymers were also prepared as comparators. Spherical NPs of around 120 nm diameter with a low polydispersity index and negative zeta potential as well as good drug loading of docetaxel were obtained. The NPs showed prolonged stability in relevant simulated biological fluids and a high ability to penetrate an artificial mucus layer due to the presence of the external PEG coating. Stability, FRET and drug release studies in conditions simulating intracellular reductive environments demonstrated a fast disassembly of the external shell of the NPs, thus triggering on-demand drug release. FACS measurements and confocal microscopy showed increased and faster uptake of RR-NPs in both 2D- and 3D- cell culture models of lung cancer compared to nRR-NPs. In particular, the 'designed-in' reductive instability of RR-NPs in conditioned cell media, the fast PEG release in the extracellular compartment, as well as a diminution of uptake rate in control experiments where extracellular thiols were neutralized, suggested a partial extracellular release of the PEG fringe that promoted rapid internalization of the residual NPs into cells. Taken together, these results provide further evidence of the effectiveness of PEGylated reducible nanocarriers to permeate mucus layer barriers, and establish a new means to enhance cancer cell uptake of drug carriers by extra-and intra-cellular cleavage of protein- and cell-shielding hydrophilic blocks.

The potential for targeted rewriting of epigenetic marks in COPD as a new therapeutic approach

Chronic obstructive pulmonary disease (COPD) is an age and smoking related progressive, pulmonary disorder presenting with poorly reversible airflow limitation as a result of chronic bronchitis and emphysema. The prevalence, disease burden for the individual, and mortality of COPD continues to increase, whereas no effective treatment strategies are available. For many years now, a combination of bronchodilators and anti-inflammatory corticosteroids has been most widely used for therapeutic management of patients with persistent COPD. However, this approach has had disappointing results as a large number of COPD patients are corticosteroid resistant. In patients with COPD, there is emerging evidence showing aberrant expression of epigenetic marks such as DNA methylation, histone modifications and microRNAs in blood, sputum and lung tissue. Therefore, novel therapeutic approaches may exist using epigenetic therapy. This review aims to describe and summarize current knowledge of aberrant expression of epigenetic marks in COPD. In addition, tools available for restoration of epigenetic marks are described, as well as delivery mechanisms of epigenetic editors to cells. Targeting epigenetic marks might be a very promising tool for treatment and lung regeneration in COPD in the future.

PEGylation for enhancing nanoparticle diffusion in mucus

The viscoelastic mucus secretions coating exposed organs such as the lung airways and the female reproductive tract can trap and quickly eliminate not only foreign pathogens and ultrafine particles but also particle-based drug delivery systems, thus limiting sustained and targeted drug delivery at mucosal surfaces. To improve particle distribution across the mucosa and enhance delivery to the underlying epithelium, many investigators have sought to develop nanoparticles capable of readily traversing mucus. The first synthetic nanoparticles shown capable of rapidly penetrating physiological mucus secretions utilized a dense coating of polyethylene glycol (PEG) covalently grafted onto the surface of preformed polymeric nanoparticles. In the decade since, PEG has become the gold standard in engineering mucus-penetrating drug carriers for sustained and targeted drug delivery to the lungs, gastrointestinal tract, eyes, and female reproductive tract. This review summarizes the history of the development of various PEG-based mucus-penetrating particles, and highlights the key physicochemical properties of PEG coatings and PEGylation strategies to achieve muco-inert PEG coatings on nanoparticle drug carriers for improved drug and gene delivery at mucosal surfaces.

MUC1 aptamer-targeted DNA micelles for dual tumor therapy using doxorubicin and KLA peptide

Targeted delivery of DNA nanoparticles is a promising approach in cancer therapy. Using aptamers, target specific delivery of DNA nanoparticles can be achieved. Further, aptamers can indirectly improve drug encapsulation efficiency of DNA nanoparticles for drugs intercalated within nucleic acid base pairs. Using DNA blocks, a micellar hybrid nanoparticle was prepared for the targeted co-delivery of doxorubicin and a pro-apoptotic peptide, KLA to tumor cells. Results demonstrated that anti-MUC1 aptamer could specifically deliver the synthesized DNA micelle into MCF-7 cells by improving its cellular uptake. Additionally, co-delivery of doxorubicin and KLA could significantly enhance the therapeutic efficacy of the construct resulting in reduction of required dose of doxorubicin that is a pivotal point in reducing chemotherapeutics side effects. Moreover, DOX-KLA-anti-MUC1-micelle remarkably inhibited tumor growth of tumor-bearing mice when compared with free drug. DOX-KLA-anti-MUC1-micelle also reduced toxic effect of free doxorubicin as determined by percent of body weight loss and survival rate in vivo.

Design and intestinal mucus penetration mechanism of core-shell nanocomplex

The objective of this study was to design intestinal mucus-penetrating core-shell nanocomplex by functionally mimicking the surface of virus, which can be used as the carrier for peroral delivery of macromolecules, and further understand the influence of nanocomplex surface properties on the mucosal permeation capacity. Taking insulin as a model drug, the core was formed by the self-assembly among positively charged chitosan, insulin and negatively charged sodium tripolyphosphate, different types of alginates were used as the shell forming material. The nanocomplex was characterized by dynamic light scattering (DLS), atomic force microscopy (AFM) and FTIR. Nanocomplex movement in mucus was recorded using multiple particle tracking (MPT) method. Permeation and uptake of different nanocomplex were studied in rat intestine. It was demonstrated that alginate coating layer was successfully formed on the core and the core-shell nanocomplex showed a good physical stability and improved enzymatic degradation protection. The mucus penetration and MPT study showed that the mucus penetration capacity of the nanocomplex was surface charge and coating polymer structure dependent, nanocomplex with negative alginate coating had 1.6-2.5 times higher mucus penetration ability than that of positively charged chitosan-insulin nanocomplex. Moreover, the mucus penetration ability of the core-shell nanocomplex was alginate structure dependent, whereas alginate with lower G content and lower molecular weight showed the best permeation enhancing ability. The improvement of intestine permeation and intestinal villi uptake of the core-shell nanocomplex were further confirmed in rat intestine and multiple uptake mechanisms were involved in the transport process. In conclusion, core-shell nanocomplex composed of oppositely charged materials could provide a strategy to overcome the mucus barrier and enhance the mucosal permeability.

New perspectives in nanotherapeutics for chronic respiratory diseases

According to the World Health Organization (WHO), hundreds of millions of people of all ages and in all countries suffer from chronic respiratory diseases, with particular negative consequences such as poor health-related quality of life, impaired work productivity, and limitations in the activities of daily living. Chronic obstructive pulmonary disease, asthma, occupational lung diseases (such as silicosis), cystic fibrosis, and pulmonary arterial hypertension are the most common of these diseases, and none of them are curable with current therapies. The advent of nanotechnology holds great therapeutic promise for respiratory conditions, because non-viral vectors are able to overcome the mucus and lung remodeling barriers, increasing pharmacologic and therapeutic potency. It has been demonstrated that the extent of pulmonary nanoparticle uptake depends not only on the physical and chemical features of nanoparticles themselves, but also on the health status of the organism; thus, the huge diversity in nanotechnology could revolutionize medicine, but safety assessment is a challenging task. Within this context, the present review discusses some of the major new perspectives in nanotherapeutics for lung disease and highlights some of the most recent studies in the field.

Polyaspartamide-Based Nanoparticles Loaded with Fluticasone Propionate and the In Vitro Evaluation towards Cigarette Smoke Effects

This paper describes the evaluation of polymeric nanoparticles (NPs) as a potential carrier for lung administration of fluticasone propionate (FP). The chosen polymeric material to produce NPs was a copolymer based on α,β-poly(N-2-hydroxyethyl)-d,l-aspartamide (PHEA) whose backbone was derivatised with different molecules, such as poly(lactic acid) (PLA) and polyethylenglycol (PEG). The chosen method to produce NPs from PHEA-PLA-PEG₂₀₀₀ was the method based on high-pressure homogenization and subsequent solvent evaporation by adding Pluronic F68 during the process and trehalose before lyophilisation. Obtained colloidal FP-loaded NPs showed a slightly negative surface charge and nanometric dimensions that are maintained after storage for one year at −20 °C and 5 °C. The FP loading was about 2.9 wt % and the drug was slowly released in simulated lung fluid. Moreover, the obtained NPs, containing the drug or not, were biocompatible and did not induce cell necrosis and cell apoptosis on bronchial epithelial cells (16-HBE). Further in vitro testing on cigarette smoke extract (CSE)-stimulated 16-HBE revealed that FP-loaded NPs were able to reduce the survivin expression, while either free FP or empty NPs were not able to significantly reduce this effect.

Protein nanocages that penetrate airway mucus and tumor tissue

Reports on drug delivery systems capable of overcoming multiple biological barriers are rare. We introduce a nanoparticle-based drug delivery technology capable of rapidly penetrating both lung tumor tissue and the mucus layer that protects airway tissues from nanoscale objects. Specifically, human ferritin heavy-chain nanocages (FTn) were functionalized with polyethylene glycol (PEG) in a unique manner that allows robust control over PEG location (nanoparticle surface only) and surface density. We varied PEG surface density and molecular weight to discover PEGylated FTn that rapidly penetrated both mucus barriers and tumor tissues in vitro and in vivo. Upon inhalation in mice, PEGylated FTn with optimized PEGylation rapidly penetrated the mucus gel layer and thus provided a uniform distribution throughout the airways. Subsequently, PEGylated FTn preferentially penetrated and distributed within orthotopic lung tumor tissue, and selectively entered cancer cells, in a transferrin receptor 1-dependent manner, which is up-regulated in most cancers. To test the potential therapeutic benefits, doxorubicin (DOX) was conjugated to PEGylated FTn via an acid-labile linker to facilitate intracellular release of DOX after cell entry. Inhalation of DOX-loaded PEGylated FTn led to 60% survival, compared with 10% survival in the group that inhaled DOX in solution at the maximally tolerated dose, in a murine model of malignant airway lung cancer. This approach may provide benefits as an adjuvant therapy combined with systemic chemo- or immunotherapy or as a stand-alone therapy for patients with tumors confined to the airways.

Impact of PEG Chain Length on the Physical Properties and Bioactivity of PEGylated Chitosan/siRNA Nanoparticles in Vitro and in Vivo

PEGylation of cationic polyplexes is a promising approach to enhance the stability and reduce unspecific interaction with biological components. Herein, we systematically investigate the impact of PEGylation on physical and biological properties of chitosan/siRNA polyplexes. A series of chitosan-PEG copolymers (CS-PEG2k, CS-PEG5k and CS-PEG10k) were synthesized with similar PEG mass content but with different molecular weight. PEGylation with higher molecular weight and less grafting degree resulted in smaller and more compacted nanoparticles with relatively higher surface charge. PEGylated polyplexes showed distinct mechanism of endocytosis, which was macropinocytosis and caveolae-dependent and clathrin-independent. In vitro silencing efficiency in HeLa and H1299 cells was significantly improved by PEGylation and CS-PEG5k/siRNA achieved the highest knockdown efficiency. Efficient silence of ribonucleotide reductase subunit M2 (RRM2) in HeLa cells by CS-PEG5k/siRRM2 significantly induced cell cycle arrest and inhibited cell proliferation. In addition, PEGylation significantly inhibited macrophage phagocytosis and unspecific interaction with red blood cells (RBCs). Significant extension of in vivo circulation was achieved only with high molecular weight PEG modification (CS-PEG10k), whereas all CS/siRNA and CS-PEG/siRNA nanoparticles showed similar pattern of biodistribution with major accumulation in liver and kidney. These results imply that PEGylation with higher molecular weight PEG and less grafting rate is a promising strategy to improve chitosan/siRNA nanocomplexes performance both in vitro and in vivo.

MR image-guided delivery of cisplatin-loaded brain-penetrating nanoparticles to invasive glioma with focused ultrasound

Systemically administered chemotherapeutic drugs are often ineffective in the treatment of invasive brain tumors due to poor therapeutic index. Within gliomas, despite the presence of heterogeneously leaky microvessels, dense extracellular matrix and high interstitial pressure generate a "blood-tumor barrier" (BTB), which inhibits drug delivery and distribution. Meanwhile, beyond the contrast MRI-enhancing edge of the tumor, invasive cancer cells are protected by the intact blood-brain barrier (BBB). Here, we tested whether brain-penetrating nanoparticles (BPN) that possess dense surface coatings of polyethylene glycol (PEG) and are loaded with cisplatin (CDDP) could be delivered across both the blood-tumor and blood-brain barriers with MR image-guided focused ultrasound (MRgFUS), and whether this treatment could control glioma growth and invasiveness. To this end, we first established that MRgFUS is capable of significantly enhancing the delivery of ~60nm fluorescent tracer BPN across the blood-tumor barrier in both the 9L (6-fold improvement) gliosarcoma and invasive F98 (28-fold improvement) glioma models. Importantly, BPN delivery across the intact BBB, just beyond the tumor edge, was also markedly increased in both tumor models. We then showed that a CDDP loaded BPN formulation (CDDP-BPN), composed of a blend of polyaspartic acid (PAA) and heavily PEGylated polyaspartic acid (PAA-PEG), was highly stable, provided extended drug release, and was effective against F98 cells in vitro. These CDDP-BPN were delivered from the systemic circulation into orthotopic F98 gliomas using MRgFUS, where they elicited a significant reduction in tumor invasiveness and growth, as well as improved animal survival. We conclude that this therapy may offer a powerful new approach for the treatment invasive gliomas, particularly for preventing and controlling recurrence.

Polymeric nanoparticles in development for treatment of pulmonary infectious diseases

Serious lung infections, such as pneumonia, tuberculosis, and chronic obstructive cystic fibrosis-related bacterial diseases, are increasingly difficult to treat and can be life-threatening. Over the last decades, an array of therapeutics and/or diagnostics have been exploited for management of pulmonary infections, but the advent of drug-resistant bacteria and the adverse conditions experienced upon reaching the lung environment urge the development of more effective delivery vehicles. Nanotechnology is revolutionizing the approach to circumventing these barriers, enabling better management of pulmonary infectious diseases. In particular, polymeric nanoparticle-based therapeutics have emerged as promising candidates, allowing for programmed design of multi-functional nanodevices and, subsequently, improved pharmacokinetics and therapeutic efficiency, as compared to conventional routes of delivery. Direct delivery to the lungs of such nanoparticles, loaded with appropriate antimicrobials and equipped with 'smart' features to overcome various mucosal and cellular barriers, is a promising approach to localize and concentrate therapeutics at the site of infection while minimizing systemic exposure to the therapeutic agents. The present review focuses on recent progress (2005-2015) important for the rational design of nanostructures, particularly polymeric nanoparticles, for the treatment of pulmonary infections with highlights on the influences of size, shape, composition, and surface characteristics of antimicrobial-bearing polymeric nanoparticles on their biodistribution, therapeutic efficacy, and toxicity. WIREs Nanomed Nanobiotechnol 2016, 8:842-871. doi: 10.1002/wnan.1401 For further resources related to this article, please visit the WIREs website.

The Mucus Barrier to Inhaled Gene Therapy

Recent evidence suggests that the airway mucus gel layer may be impermeable to the viral and synthetic gene vectors used in past inhaled gene therapy clinical trials for diseases like cystic fibrosis. These findings support the logic that inhaled gene vectors that are incapable of penetrating the mucus barrier are unlikely to provide meaningful benefit to patients. In this review, we discuss the biochemical and biophysical features of mucus that contribute its barrier function, and how these barrier properties may be reinforced in patients with lung disease. We next review biophysical techniques used to assess the potential ability of gene vectors to penetrate airway mucus. Finally, we provide new data suggesting that fresh human airway mucus should be used to test the penetration rates of gene vectors. The physiological barrier properties of spontaneously expectorated CF sputum remained intact up to 24 hours after collection when refrigerated at 4 °C. Conversely, the barrier properties were significantly altered after freezing and thawing of sputum samples. Gene vectors capable of overcoming the airway mucus barrier hold promise as a means to provide the widespread gene transfer throughout the airway epithelium required to achieve meaningful patient outcomes in inhaled gene therapy clinical trials.

Influence of PEGylation on nanoparticle mobility in different models of the extracellular matrix

Nanoparticle transport inside the extracellular matrix (ECM) is a crucial factor affecting the therapeutic success. In this work, two in vitro ECM models - a neutrally charged collagen I network with an effective pore size of 0.47μm and Matrigel, a basement membrane matrix with strong negative charge and effective pore size of 0.14μm - were assessed for barrier function in the context of diffusing nanoparticles. Nanoparticles with a size of 120nm were coated with poly(ethylene glycol) (PEG) of different molecular weights - 2, 5 and 20kDa - over a range of gradually increasing coating densities - precisely 0.2, 2, 8 and 20PEG/nm². The PEG corona was imaged in its native state without any drying process by atomic force microscopy, revealing that the experimentally determined arrangement of PEG at the surface did not match with what was theoretically expected. In a systematic investigation of nanoparticle mobility via fluorescence recovery after photobleaching, increasing both PEG MW and PEGylation density gradually improved diffusion properties predominately in collagen. Due to its smaller pore size and electrostatic obstruction, diffusion coefficients were about ten times lower in Matrigel than in the collagen network and an extension of the PEG MW and density did not necessarily lead to better diffusing particles. Consequently, collagen gels were revealed to be a poor model for nanoparticle mobility assessment, as neither their pore size nor their electrostatic properties reflect the expected in vivo conditions. In Matrigel, diffusion proceeded according to a sigmoidal increase with gradually increasing PEG densities showing threshold zeta potentials of 11.6mV (PEG_2kDa) and 13.8mV (PEG_5kDa), below which particles were regarded as mobile. Irrespective of the molecular weight particles with a PEGylation density lower than 2PEG/nm² were defined as immobile and those with a PEG coverage of more than 8PEG/nm² as mobile.

Barriers to inhaled gene therapy of obstructive lung diseases: A review

Knowledge of genetic origins of obstructive lung diseases has made inhaled gene therapy an attractive alternative to the current standards of care that are limited to managing disease symptoms. Initial lung gene therapy clinical trials occurred in the early 1990s following the discovery of the genetic defect responsible for cystic fibrosis (CF), a monogenic disorder. However, despite over two decades of intensive effort, gene therapy has yet to help patients with CF or any other obstructive lung disease. The slow progress is due in part to poor understanding of the biological barriers to inhaled gene therapy. Encouragingly, clinical trials have shown that inhaled gene therapy with various viral vectors and non-viral gene vectors is well tolerated by patients, and continued research has provided valuable lessons and resources that may lead to future success of this therapeutic strategy. In this review, we first introduce representative obstructive lung diseases and examine limitations of currently available therapeutic options. We then review key components for successful execution of inhaled gene therapy, including gene delivery systems, primary physiological barriers and strategies to overcome them, and advances in preclinical disease models with which the most promising systems may be identified for human clinical trials.

PEGylation as a strategy for improving nanoparticle-based drug and gene delivery

Coating the surface of nanoparticles with polyethylene glycol (PEG), or "PEGylation", is a commonly used approach for improving the efficiency of drug and gene delivery to target cells and tissues. Building from the success of PEGylating proteins to improve systemic circulation time and decrease immunogenicity, the impact of PEG coatings on the fate of systemically administered nanoparticle formulations has, and continues to be, widely studied. PEG coatings on nanoparticles shield the surface from aggregation, opsonization, and phagocytosis, prolonging systemic circulation time. Here, we briefly describe the history of the development of PEGylated nanoparticle formulations for systemic administration, including how factors such as PEG molecular weight, PEG surface density, nanoparticle core properties, and repeated administration impact circulation time. A less frequently discussed topic, we then describe how PEG coatings on nanoparticles have also been utilized for overcoming various biological barriers to efficient drug and gene delivery associated with other modes of administration, ranging from gastrointestinal to ocular. Finally, we describe both methods for PEGylating nanoparticles and methods for characterizing PEG surface density, a key factor in the effectiveness of the PEG surface coating for improving drug and gene delivery.

Designer nanoparticle: nanobiotechnology tool for cell biology

This article discusses the use of nanotechnology for subcellular compartment isolation and its application towards subcellular omics. This technology review significantly contributes to our understanding on use of nanotechnology for subcellular systems biology. Here we elaborate nanobiotechnology approach of using superparamagnetic nanoparticles (SPMNPs) optimized with different surface coatings for subcellular organelle isolation. Using pulse-chase approach, we review that SPMNPs interacted differently with the cell depending on its surface functionalization. The article focuses on the use of functionalized-SPMNPs as a nanobiotechnology tool to isolate high quality (both purity and yield) plasma membranes and endosomes or lysosomes. Such nanobiotechnology tool can be applied in generating subcellular compartment inventories. As a future perspective, this strategy could be applied in areas such as immunology, cancer and stem cell research.

Targeted gene transfer to the brain via the delivery of brain-penetrating DNA nanoparticles with focused ultrasound

Gene therapy holds promise for the treatment of many pathologies of the central nervous system (CNS), including brain tumors and neurodegenerative diseases. However, the delivery of systemically administered gene carriers to the CNS is hindered by both the blood-brain barrier (BBB) and the nanoporous and electrostatically charged brain extracelluar matrix (ECM), which acts as a steric and adhesive barrier. We have previously shown that these physiological barriers may be overcome by, respectively, opening the BBB with MR image-guided focused ultrasound (FUS) and microbubbles and using highly compact "brain penetrating" nanoparticles (BPN) coated with a dense polyethylene glycol corona that prevents adhesion to ECM components. Here, we tested whether this combined approach could be utilized to deliver systemically administered DNA-bearing BPN (DNA-BPN) across the BBB and mediate localized, robust, and sustained transgene expression in the rat brain. Systemically administered DNA-BPN delivered through the BBB with FUS led to dose-dependent transgene expression only in the FUS-treated region that was evident as early as 24h post administration and lasted for at least 28days. In the FUS-treated region ~42% of all cells, including neurons and astrocytes, were transfected, while less than 6% were transfected in the contralateral non-FUS treated hemisphere. Importantly, this was achieved without any sign of toxicity or astrocyte activation. We conclude that the image-guided delivery of DNA-BPN with FUS and microbubbles constitutes a safe and non-invasive strategy for targeted gene therapy to the brain.

Non-viral gene therapy: Gains and challenges of non-invasive administration methods

Gene therapy is becoming an influential part of the rapidly increasing armamentarium of biopharmaceuticals for improving health and combating diseases. Currently, three gene therapy treatments are approved by regulatory agencies. While these treatments utilize viral vectors, non-viral alternative technologies are also being developed to improve the safety profile and manufacturability of gene carrier formulations. We present an overview of gene-based therapies focusing on non-viral gene delivery systems and the genetic therapeutic tools that will further revolutionize medical treatment with primary focus on the range and development of non-invasive delivery systems for dermal, transdermal, ocular and pulmonary administrations and perspectives on other administration methods such as intranasal, oral, buccal, vaginal, rectal and otic delivery.

Drug and gene delivery across the blood-brain barrier with focused ultrasound

The blood-brain barrier (BBB) remains one of the most significant limitations to treatments of central nervous system (CNS) disorders including brain tumors, neurodegenerative diseases and psychiatric disorders. It is now well-established that focused ultrasound (FUS) in conjunction with contrast agent microbubbles may be used to non-invasively and temporarily disrupt the BBB, allowing localized delivery of systemically administered therapeutic agents as large as 100nm in size to the CNS. Importantly, recent technological advances now permit FUS application through the intact human skull, obviating the need for invasive and risky surgical procedures. When used in combination with magnetic resonance imaging, FUS may be applied precisely to pre-selected CNS targets. Indeed, FUS devices capable of sub-millimeter precision are currently in several clinical trials. FUS mediated BBB disruption has the potential to fundamentally change how CNS diseases are treated, unlocking potential for combinatorial treatments with nanotechnology, markedly increasing the efficacy of existing therapeutics that otherwise do not cross the BBB effectively, and permitting safe repeated treatments. This article comprehensively reviews recent studies on the targeted delivery of therapeutics into the CNS with FUS and offers perspectives on the future of this technology.

Particle tracking in drug and gene delivery research: State-of-the-art applications and methods

Particle tracking is a powerful microscopy technique to quantify the motion of individual particles at high spatial and temporal resolution in complex fluids and biological specimens. Particle tracking's applications and impact in drug and gene delivery research have greatly increased during the last decade. Thanks to advances in hardware and software, this technique is now more accessible than ever, and can be reliably automated to enable rapid processing of large data sets, thereby further enhancing the role that particle tracking will play in drug and gene delivery studies in the future. We begin this review by discussing particle tracking-based advances in characterizing extracellular and cellular barriers to therapeutic nanoparticles and in characterizing nanoparticle size and stability. To facilitate wider adoption of the technique, we then present a user-friendly review of state-of-the-art automated particle tracking algorithms and methods of analysis. We conclude by reviewing technological developments for next-generation particle tracking methods, and we survey future research directions in drug and gene delivery where particle tracking may be useful.

Highly compacted biodegradable DNA nanoparticles capable of overcoming the mucus barrier for inhaled lung gene therapy

Gene therapy has emerged as an alternative for the treatment of diseases refractory to conventional therapeutics. Synthetic nanoparticle-based gene delivery systems offer highly tunable platforms for the delivery of therapeutic genes. However, the inability to achieve sustained, high-level transgene expression in vivo presents a significant hurdle. The respiratory system, although readily accessible, remains a challenging target, as effective gene therapy mandates colloidal stability in physiological fluids and the ability to overcome biological barriers found in the lung. We formulated highly stable DNA nanoparticles based on state-of-the-art biodegradable polymers, poly(β-amino esters) (PBAEs), possessing a dense corona of polyethylene glycol. We found that these nanoparticles efficiently penetrated the nanoporous and highly adhesive human mucus gel layer that constitutes a primary barrier to reaching the underlying epithelium. We also discovered that these PBAE-based mucus-penetrating DNA nanoparticles (PBAE-MPPs) provided uniform and high-level transgene expression throughout the mouse lungs, superior to several gold standard gene delivery systems. PBAE-MPPs achieved robust transgene expression over at least 4 mo following a single administration, and their transfection efficiency was not attenuated by repeated administrations, underscoring their clinical relevance. Importantly, PBAE-MPPs demonstrated a favorable safety profile with no signs of toxicity following intratracheal administration.

Targeted polymeric nanoparticles for cancer gene therapy

In this article, advances in designing polymeric nanoparticles for targeted cancer gene therapy are reviewed. Characterization and evaluation of biomaterials, targeting ligands, and transcriptional elements are each discussed. Advances in biomaterials have driven improvements to nanoparticle stability and tissue targeting, conjugation of ligands to the surface of polymeric nanoparticles enable binding to specific cancer cells, and the design of transcriptional elements has enabled selective DNA expression specific to the cancer cells. Together, these features have improved the performance of polymeric nanoparticles as targeted non-viral gene delivery vectors to treat cancer. As polymeric nanoparticles can be designed to be biodegradable, non-toxic, and to have reduced immunogenicity and tumorigenicity compared to viral platforms, they have significant potential for clinical use. Results of polymeric gene therapy in clinical trials and future directions for the engineering of nanoparticle systems for targeted cancer gene therapy are also presented.

Targeted lung cancer therapy: preparation and optimization of transferrin-decorated nanostructured lipid carriers as novel nanomedicine for co-delivery of anticancer drugs and DNA

Purpose

Nanostructured lipid carriers (NLC) represent an improved generation of lipid nanoparticles. They have specific nanostructures to accommodate drugs/genes, and thus achieve higher loading capacity. The aim of this study was to develop transferrin (Tf)-decorated NLC as multifunctional nanomedicine for co-delivery of paclitaxel (PTX) and enhanced green fluorescence protein plasmid.

Methods

Firstly, Tf-conjugated ligands were synthesized. Secondly, PTX- and DNA-loaded NLC (PTX-DNA-NLC) was prepared. Finally, Tf-containing ligands were used for the surface decoration of NLC. Their average size, zeta potential, drug, and gene loading were evaluated. Human non-small cell lung carcinoma cell line (NCl-H460 cells) was used for the testing of in vitro transfection efficiency, and in vivo transfection efficiency of NLC was evaluated on mice bearing NCl-H460 cells.

Results

Tf-decorated PTX and DNA co-encapsulated NLC (Tf-PTX-DNA-NLC) were nano-sized particles with positive zeta potential. Tf-PTX-DNA-NLC displayed low cytotoxicity, high gene transfection efficiency, and enhanced antitumor activity in vitro and in vivo.

Conclusion

The results demonstrated that Tf-PTX-DNA-NLC can achieve impressive antitumor activity and gene transfection efficiency. Tf decoration also enhanced the active targeting ability of the carriers to NCl-H460 cells. The novel drug and gene delivery system offers a promising strategy for the treatment of lung cancer.

Hitting the bull's eye: targeting HMGA1 in cancer stem cells

Emerging evidence suggests that when cancer cells hijack normal stem cell properties, they acquire the ability to invade, metastasize to distant sites and evade therapy. Thus, eliminating cancer cells with stem cell properties, or cancer stem cells, is of prime importance for the successful treatment of cancer, regardless of the tissue of origin. Previous efforts to target cancer stem cells (CSCs), however, have been largely unsuccessful. Recent studies led to the discovery of a novel role for the high mobility group A1 (HMGA1) protein as a master regulator in both CSCs and normal embryonic stem cells. Here, we present exciting new work unveiling HMGA1 as a promising target for therapies directed at eradicating CSCs.