Intranasal delivery of targeted polyfunctional gold-iron oxide nanoparticles loaded with therapeutic microRNAs for combined theranostic multimodality imaging and presensitization of glioblastoma to temozolomide

miRacle of microRNA-Driven Cancer Nanotherapeutics

MicroRNAs (miRNAs) are non-protein-coding RNA molecules 20-25 nucleotides in length that can suppress the expression of genes involved in numerous physiological processes in cells. Accumulating evidence has shown that dysregulation of miRNA expression is related to the pathogenesis of various human diseases and cancers. Thus, stragegies involving either restoring the expression of tumor suppressor miRNAs or inhibiting overexpressed oncogenic miRNAs hold potential for targeted cancer therapies. However, delivery of miRNAs to tumor tissues is a challenging task. Recent advances in nanotechnology have enabled successful tumor-targeted delivery of miRNA therapeutics through newly designed nanoparticle-based carrier systems. As a result, miRNA therapeutics have entered human clinical trials with promising results, and they are expected to accelerate the transition of miRNAs from the bench to the bedside in the next decade. Here, we present recent perspectives and the newest developments, describing several engineered natural and synthetic novel miRNA nanocarrier formulations and their key in vivo applications and clinical trials.

Inhaled Gold Nano-star Carriers for Targeted Delivery of Triple Suicide Gene Therapy and Therapeutic MicroRNAs to Lung Metastases: Development and Validation in a Small Animal Model

Pulmonary metastases pose significant treatment challenges for many cancers, including triple-negative breast cancer (TNBC). We developed and tested a novel suicide gene and therapeutic microRNAs (miRs) combination therapy against lung metastases in vivo in mouse models after intranasal delivery using nontoxic gold nanoparticles (AuNPs) formulated to carry these molecular therapeutics. We used AuNPs coated with chitosan-β-cyclodextrin (CS-CD) and functionalized with a urokinase plasminogen activator (uPA) peptide to carry triple cancer suicide genes (thymidine kinase-p53-nitroreductase: TK-p53-NTR) plus therapeutic miRNAs (antimiR-21, antimiR-10b and miR-100). We synthesized three AuNPs: 20nm nanodots (AuND), and 20nm or 50nm nanostars (AuNS), then surface coated these with CS-CD using a microfluidic-optimized method. We sequentially coated the resulting positively charged AuNP-CS-CD core with synthetic miRNAs followed by TK-p53-NTR via electrostatic interactions, and added uPA peptide through CD-adamantane host-guest chemistry. A comparison of transfection efficiencies for different AuNPs showed that the 50nm AuNS allowed ∼4.16-fold higher gene transfection than other NPs. The intranasal delivery of uPA-AuNS-TK-p53-NTR-microRNAs NPs (pAuNS@TK-p53-NTR-miRs) in mice predominantly accumulated in lungs and facilitated ganciclovir and CB1954 prodrug-mediated gene therapy against TNBC lung metastases. This new nanosystem may serve as an adaptable-across-cancer-type, facile, and clinically scalable platform to allow future inhalational suicide gene-miR combination therapy for patients harboring pulmonary metastases.

MicroRNA delivery systems in glioma therapy and perspectives: A systematic review

Gliomas are the deadliest of all primary brain tumors, and they constitute a serious global health problem. MicroRNAs (miRNAs) are gene expression regulators associated with glioma pathogenesis. Thus, miRNAs represent potential therapeutic agents for treating gliomas. However, miRNAs have not been established as part of the regular clinical armamentarium. This systemic review evaluates current molecular and pre-clinical studies with the aim of defining the most appealing supramolecular platform for administering therapeutic miRNA to patients with gliomas. An integrated analysis suggested that cationic lipid nanoparticles, functionalized with octa-arginine peptides, represent a potentially specific, practical, non-invasive intervention for treating gliomas. This supramolecular platform allows loading both hydrophilic (miRNA) and hydrophobic (anti-tumor drugs, like temozolomide) molecules. This systemic review is the first to describe miRNA delivery systems targeted to gliomas that integrate several types of molecules as active ingredients. Further experimental validation is warranted to confirm the practical value of miRNA delivery systems.

Mitochondrial Genetic and Epigenetic Regulations in Cancer: Therapeutic Potential

Mitochondria are dynamic organelles managing crucial processes of cellular metabolism and bioenergetics. Enabling rapid cellular adaptation to altered endogenous and exogenous environments, mitochondria play an important role in many pathophysiological states, including cancer. Being under the control of mitochondrial and nuclear DNA (mtDNA and nDNA), mitochondria adjust their activity and biogenesis to cell demands. In cancer, numerous mutations in mtDNA have been detected, which do not inactivate mitochondrial functions but rather alter energy metabolism to support cancer cell growth. Increasing evidence suggests that mtDNA mutations, mtDNA epigenetics and miRNA regulations dynamically modify signalling pathways in an altered microenvironment, resulting in cancer initiation and progression and aberrant therapy response. In this review, we discuss mitochondria as organelles importantly involved in tumorigenesis and anti-cancer therapy response. Tumour treatment unresponsiveness still represents a serious drawback in current drug therapies. Therefore, studying aspects related to genetic and epigenetic control of mitochondria can open a new field for understanding cancer therapy response. The urgency of finding new therapeutic regimens with better treatment outcomes underlines the targeting of mitochondria as a suitable candidate with new therapeutic potential. Understanding the role of mitochondria and their regulation in cancer development, progression and treatment is essential for the development of new safe and effective mitochondria-based therapeutic regimens.

Efficient spatially targeted gene editing using a near-infrared activatable protein-conjugated nanoparticle for brain applications

Spatial control of gene expression is critical to modulate cellular functions and deconstruct the function of individual genes in biological processes. Light-responsive gene-editing formulations have been recently developed; however, they have shown limited applicability in vivo due to poor tissue penetration, limited cellular transfection and the difficulty in evaluating the activity of the edited cells. Here, we report a formulation composed of upconversion nanoparticles conjugated with Cre recombinase enzyme through a photocleavable linker, and a lysosomotropic agent that facilitates endolysosomal escape. This formulation allows in vitro spatial control in gene editing after activation with near-infrared light. We further demonstrate the potential of this formulation in vivo through three different paradigms: (i) gene editing in neurogenic niches, (ii) gene editing in the ventral tegmental area to facilitate monitoring of edited cells by precise optogenetic control of reward and reinforcement, and (iii) gene editing in a localized brain region via a noninvasive administration route (i.e., intranasal).

Spatial control of gene expression allows precise control over biological processes. Here, the authors develop an efficient light-responsive formulation based on upconversion nanoparticles, and demonstrate on-demand genetic manipulation in deep brain tissue.

A rationally identified panel of microRNAs targets multiple oncogenic pathways to enhance chemotherapeutic effects in glioblastoma models

Glioblastoma (GBM) is the most common malignant brain tumor. Available treatments have limited success because most patients develop chemoresistance. Alternative strategies are required to improve anticancer effects of current chemotherapeutics while limiting resistance. Successful targeting of microRNAs (miRNAs) as regulators of gene expression can help reprogram GBM cells to better respond to chemotherapy. We aimed to identify a panel of miRNAs that target multiple oncogenic pathways to improve GBM therapy. We first identified differentially expressed miRNAs and tested if their target genes play central roles in GBM signaling pathways by analyzing data in the Gene Expression Omnibus and The Cancer Genome Atlas databases. We then studied the effects of different combinations of these miRNAs in GBM cells by delivering synthetic miRNAs using clinically compatible PLGA-PEG nanoparticles prior to treatment with temozolomide (TMZ) or doxorubicin (DOX). The successful miRNA panel was tested in mice bearing U87-MG cells co-treated with TMZ. We identified a panel of five miRNAs (miRNA-138, miRNA-139, miRNA-218, miRNA-490, and miRNA-21) and their oncogenic targets (CDK6, ZEB1, STAT3, TGIF2, and SMAD7) that cover four different signaling pathways (cell proliferation and apoptotic signaling, invasion and metastasis, cytokine signaling, and stemness) in GBM. We observed significant in vitro and in vivo enhancement of therapeutic efficiency of TMZ and DOX in GBM models. The proposed combination therapy using rationally selected miRNAs and chemotherapeutic drugs is effective owing to the ability of this specific miRNA panel to better target multiple genes associated with the hallmarks of cancer.

Glioblastoma: Current Status, Emerging Targets, and Recent Advances

Glioblastoma (GBM) is a highly malignant brain tumor characterized by a heterogeneous population of genetically unstable and highly infiltrative cells that are resistant to chemotherapy. Although substantial efforts have been invested in the field of anti-GBM drug discovery in the past decade, success has primarily been confined to the preclinical level, and clinical studies have often been hampered due to efficacy-, selectivity-, or physicochemical property-related issues. Thus, expansion of the list of molecular targets coupled with a pragmatic design of new small-molecule inhibitors with central nervous system (CNS)-penetrating ability is required to steer the wheels of anti-GBM drug discovery endeavors. This Perspective presents various aspects of drug discovery (challenges in GBM drug discovery and delivery, therapeutic targets, and agents under clinical investigation). The comprehensively covered sections include the recent medicinal chemistry campaigns embarked upon to validate the potential of numerous enzymes/proteins/receptors as therapeutic targets in GBM.

Metal-Based Nanostructured Therapeutic Strategies for Glioblastoma Treatment-An Update

Glioblastoma (GBM) is the most commonly diagnosed and most lethal primary malignant brain tumor in adults. Standard treatments are ineffective, and despite promising results obtained in early phases of experimental clinical trials, the prognosis of GBM remains unfavorable. Therefore, there is need for exploration and development of innovative methods that aim to establish new therapies or increase the effectiveness of existing therapies. One of the most exciting new strategies enabling combinatory treatment is the usage of nanocarriers loaded with chemotherapeutics and/or other anticancer compounds. Nanocarriers exhibit unique properties in antitumor therapy, as they allow highly efficient drug transport into cells and sustained intracellular accumulation of the delivered cargo. They can be infused into and are retained by GBM tumors, and potentially can bypass the blood-brain barrier. One of the most promising and extensively studied groups of nanostructured therapeutics are metal-based nanoparticles. These theranostic nanocarriers demonstrate relatively low toxicity, thus they might be applied for both diagnosis and therapy. In this article, we provide an update on metal-based nanostructured constructs in the treatment of GBM. We focus on the interaction of metal nanoparticles with various forms of electromagnetic radiation for use in photothermal, photodynamic, magnetic hyperthermia and ionizing radiation sensitization applications.

Nanoparticle delivery systems for substance use disorder

Innovative breakthroughs in nanotechnology are having a substantial impact in healthcare, especially for brain diseases where effective therapeutic delivery systems are desperately needed. Nanoparticle delivery systems offer an unmatched ability of not only conveying a diverse array of diagnostic and therapeutic agents across complex biological barriers, but also possess the ability to transport payloads to targeted cell types over a sustained period. In substance use disorder (SUD), many therapeutic targets have been identified in preclinical studies, yet few of these findings have been translated to effective clinical treatments. The lack of success is, in part, due to the significant challenge of delivering novel therapies to the brain and specific brain cells. In this review, we evaluate the potential approaches and limitations of nanotherapeutic brain delivery systems. We also highlight the examples of promising strategies and future directions of nanocarrier-based treatments for SUD.

Lipid nanocapsules for intracellular delivery of microRNA: a first step towards intervertebral disc degeneration therapy

Approximately 40% of cases of lower back pain are caused by disc degeneration disease (DDD). It is well established that microRNA (miR) dysregulation is a key player in various diseases, and its impact on DDD has recently been highlighted. RNAi (miR in particular) is increasingly being considered as a novel therapeutic tool. However, free miR is degraded rapidly in vivo, and its protection is thus a prerequisite. Nanoparticular platforms, such as lipid nanocapsules (LNC), could be specifically adapted for miR delivery, allowing the transfer and release of miR in the cell cytoplasm. The objective of the current study was to formulate and characterize miR-loaded LNC to establish their in vitro potential (cell internalization, bioactivity) as well as to determine the safety and feasibility of in situ intervertebral disc (IVD) injection of miR LNC in a healthy sheep model. Using a miR library, miR-155 was clearly identified as being involved in the DDD process and was selected for further assessment. miR-155-loaded LNC (miR-155 LNC) were successfully formulated using a phase inversion process, with the addition of lipoplexes in the cooling step. Following purification, miR-155 LNC were fully characterized, and the optimized formulation had an average diameter of 75 nm, a polydispersity index below 0.1, and a positive zeta potential. By fluorescence spectroscopy, an encapsulation efficiency (EE) of 75.6% and a drug loading (DL) of 0.6% were obtained, corresponding to a sufficient amount of miR per mL of LNC to potentially have a biological effect. The sustained release of miR-155 from LNC was demonstrated compared with free miR-155: only 22% was released after 2 h and 58% after 24 h. miR-155 protection against endonuclease degradation by LNC was confirmed by gel electrophoresis, a sine qua non condition for it to be administered in vivo. Cell viability assays were performed on human adipose stromal cells (hASCs) and ovine Nucleus pulposus cells (oNP), and a cytotoxicity of less than 30% was obtained at the considered concentrations. Additionally, miR-155 LNC cell internalization was demonstrated by flow cytometry and confocal imaging. Moreover, downregulation of total ERK1/2 in hASCs and oNP cells, after miR-155 LNC treatment, was demonstrated by Western blot and quantitative reverse-transcription PCR (qRT-PCR), thus confirming maintenance of its bioactivity after formulation and internalization. Finally, the feasibility and safety of miR-155 LNC in situ injection (compared to control groups: blank LNC and sham condition) was demonstrated in healthy sheep by imaging (MRI and T2wsi measurement) and histology (Boos' scoring) analysis. T2wsi was measured, and no significant difference was observed three months after the injection between the different conditions. No histological impact was observed, with no significant difference in Boos' scoring between the different conditions. All these results suggest LNC may be a potent strategy for the encapsulation and delivery of miR (particularly miR-155) and can be considered as a first step towards IVD regenerative medicine.

Role of Nano-miRNAs in Diagnostics and Therapeutics

MicroRNAs (miRNA) are key regulators of gene expression, controlling different biological processes such as cellular development, differentiation, proliferation, metabolism, and apoptosis. The relationships between miRNA expression and the onset and progression of different diseases, such as tumours, cardiovascular and rheumatic diseases, and neurological disorders, are well known. A nanotechnology-based approach could match miRNA delivery and detection to move beyond the proof-of-concept stage. Different kinds of nanotechnologies can have a major impact on the diagnosis and treatment of miRNA-related diseases such as cancer. Developing novel methodologies aimed at clinical practice represents a big challenge for the early diagnosis of specific diseases. Within this context, nanotechnology represents a wide emerging area at the forefront of research over the last two decades, whose potential has yet to be fully attained. Nanomedicine, derived from nanotechnology, can exploit the unique properties of nanometer-sized particles for diagnostic and therapeutic purposes. Through nanomedicine, specific treatment to counteract only cancer-cell proliferation will be improved, while leaving healthy cells intact. In this review, we dissect the properties of different nanocarriers and their roles in the early detection and treatment of cancer.

Intranasal Delivery of Functionalized Polymeric Nanomaterials to the Brain

Intravenous delivery of nanomaterials containing therapeutic agents and various cargos for treating neurological disorders is often constrained by low delivery efficacy due to difficulties in passing the blood-brain barrier (BBB). Nanoparticles (NPs) administered intranasally can move along olfactory and trigeminal nerves so that they do not need to pass through the BBB, allowing non-invasive, direct access to selective neural pathways within the brain. Hence, intranasal (IN) administration of NPs can effectively deliver drugs and genes into targeted regions of the brain, holding potential for efficacious disease treatment in the central nervous system (CNS). In this review, current methods for delivering conjugated NPs to the brain are primarily discussed. Distinctive potential mechanisms of therapeutic nanocomposites delivered via IN pathways to the brain are then discussed. Recent progress in developing functional NPs for applications in multimodal bioimaging, drug delivery, diagnostics, and therapeutics is also reviewed. This review is then concluded by discussing existing challenges, new directions, and future perspectives in IN delivery of nanomaterials.

Review: RNA-based diagnostic markers discovery and therapeutic targets development in cancer

The present review aimed to outline different types of RNAs in cancer diagnostics and treatment, and to provide novel insights into their clinical applications. RNAs, including mRNA, long non-coding (lnc)RNA, circular (circ)RNA and micro (mi)RNA, are now increasingly utilized in the diagnosis and treatment of various cancers. Each aforementioned type of RNA possess their own unique characteristics and could be aberrantly expressed as diagnostic markers or therapeutic targets in different cancers. In addition to mRNAs, which have become a promising alternative in cancer diagnostics and therapy, the uses of lncRNA, circRNA and miRNA in predictive tumor diagnostics and therapy has rapidly increased in recent years. In the present review, the mechanisms of mRNA, lncRNA, circRNA and miRNA in regulating and participating in the development of different cancers were determined, and their potential capacity in cancer diagnostics and therapy were investigated. In addition, the present review analyzed the assoaciations between different RNAs and their subsequent potential in cancer prediction and treatment.

Chemical Modification of Chitosan for Developing Cancer Nanotheranostics

Cancer is a worldwide public health issue that has not been conquered. Theranostics, the combination of a therapeutic drug and imaging agent in one formulation using nanomaterials, has been developed to better cure cancer in recent years. Although diverse biomaterials have been applied in cancer theranostics, chitosan (CS), a natural polysaccharide bearing easy modification sites with excellent biocompatibility and biodegradability, shows great potential for developing cancer nanotheranostics. In this review, we seek to describe the chemical functionalities of CS used in cancer theranostics and their synthesis methods. We also present recent discoveries and research progresses on how the CS functionalization could improve the delivery efficiency of CS-based nanotheranostics. Finally, we report several case studies about the application of CS-based nanotheranostics. This paper focuses on the strategies to construct CS-based theranostics systems via chemical routes and highlights their applications in cancer treatment, which can provide useful references for further studies.

Intranasal Delivery in Glioblastoma treatment: Prospective Molecular Treatment Modalities

Glioblastoma multiforme (GBM) is rare and fatal glioma with limited treatment options. Treatments provide minimal improvement in prognosis and only 6.8% of GBM patients have a life expectancy greater than five years. Surgical resection of this malignant glioma is difficult due to its highly invasive nature and follow-up radiotherapy with concomitant temozolomide, the currently approved standard of care, and will only extend the life of patients by a few months. It has been nearly two decades since the approval of temozolomide and there have been no clinically relevant major breakthroughs since, painting a dismal picture for patients with GBM. Although the future of GBM management seems bleak, there are many new treatment options on the horizon that propose methods of delivery to circumvent current limitations in the standard of care, i.e., the blood brain barrier and treatment resistance mechanisms. The nose is a highly accessible non-invasive route of delivery that has been incorporated into many investigational studies within the past five years and potentially paves the path to a brighter future for the management of GBM. Intranasal administration has its limitations however, as drugs can be degraded and/or fail to reach the site of action. This has prompted many studies for implementation of nanoparticle systems to overcome these limitations and to accurately deliver drugs to the site of action. This review highlights the advances in intranasal therapy delivery and impact of nanotechnology in the management of GBM and discusses potential treatment modalities that show promise for further investigation.

Overcoming Vascular Barriers to Improve the Theranostic Outcomes of Nanomedicines

Nanotheranostics aims to utilize nanomaterials to prevent, diagnose, and treat diseases to improve the quality of patients' lives. Blood vessels are responsible to deliver nutrients and oxygen to the whole body, eliminate waste, and provide access for patrolling immune cells for healthy tissues. Meanwhile, they can also nourish disease tissues, spread disease factors or cells into other healthy tissues, and deliver nanotheranostic agents to cover all the regions of a disease tissue. Thus, blood vessels are the first and the most important barrier for highly efficient nanotheranostics. Here, the structure and function of blood vessels are explored and how these characteristics affect nanotheranostics is discussed. Moreover, new mechanisms and related strategies about overcoming vascular obstacles for improved nanotheranostic outcomes are critically summarized, and their merits and demerits of each strategy are analyzed. Moreover, the present challenges to completely exhibit the potential of overcoming vascular barriers to improve the theranostic outcomes of nanomedicines in life science are also discussed. Finally, the future perspective is further discussed.

Anti-Parkinsonian Therapy: Strategies for Crossing the Blood-Brain Barrier and Nano-Biological Effects of Nanomaterials

Parkinson's disease (PD), a neurodegenerative disease that shows a high incidence in older individuals, is becoming increasingly prevalent. Unfortunately, there is no clinical cure for PD, and novel anti-PD drugs are therefore urgently required. However, the selective permeability of the blood-brain barrier (BBB) poses a huge challenge in the development of such drugs. Fortunately, through strategies based on the physiological characteristics of the BBB and other modifications, including enhancement of BBB permeability, nanotechnology can offer a solution to this problem and facilitate drug delivery across the BBB. Although nanomaterials are often used as carriers for PD treatment, their biological activity is ignored. Several studies in recent years have shown that nanomaterials can improve PD symptoms via their own nano-bio effects. In this review, we first summarize the physiological features of the BBB and then discuss the design of appropriate brain-targeted delivery nanoplatforms for PD treatment. Subsequently, we highlight the emerging strategies for crossing the BBB and the development of novel nanomaterials with anti-PD nano-biological effects. Finally, we discuss the current challenges in nanomaterial-based PD treatment and the future trends in this field. Our review emphasizes the clinical value of nanotechnology in PD treatment based on recent patents and could guide researchers working in this area in the future.

Untangling Mucosal Drug Delivery: Engineering, Designing, and Testing Nanoparticles to Overcome the Mucus Barrier

Mucus is a complex viscoelastic gel and acts as a barrier covering much of the soft tissue in the human body. High vascularization and accessibility have motivated drug delivery to various mucosal surfaces; however, these benefits are hindered by the mucus layer. To overcome the mucus barrier, many nanomedicines have been developed, with the goal of improving the efficacy and bioavailability of drug payloads. Two major nanoparticle-based strategies have emerged to facilitate mucosal drug delivery, namely, mucoadhesion and mucopenetration. Generally, mucoadhesive nanoparticles promote interactions with mucus for immobilization and sustained drug release, whereas mucopenetrating nanoparticles diffuse through the mucus and enhance drug uptake. The choice of strategy depends on many factors pertaining to the structural and compositional characteristics of the target mucus and mucosa. While there have been promising results in preclinical studies, mucus-nanoparticle interactions remain poorly understood, thus limiting effective clinical translation. This article reviews nanomedicines designed with mucoadhesive or mucopenetrating properties for mucosal delivery, explores the influence of site-dependent physiological variation among mucosal surfaces on efficacy, transport, and bioavailability, and discusses the techniques and models used to investigate mucus-nanoparticle interactions. The effects of non-homeostatic perturbations on protein corona formation, mucus composition, and nanoparticle performance are discussed in the context of mucosal delivery. The complexity of the mucosal barrier necessitates consideration of the interplay between nanoparticle design, tissue-specific differences in mucus structure and composition, and homeostatic or disease-related changes to the mucus barrier to develop effective nanomedicines for mucosal delivery.

Using nanotechnology to deliver biomolecules from nose to brain - peptides, proteins, monoclonal antibodies and RNA

There is a growing number of biomolecules, including peptides, proteins, monoclonal antibodies and RNA, that could be potentially used for the treatment of central nervous system (CNS) diseases. However, the realization of their potential is being hampered by the extraordinary difficulties these complex biomolecules have to reach the brain in therapeutically meaningful amounts. Nose-to-brain (N-to-B) delivery is now being investigated as a potential option for the direct transport of biomolecules from the nasal cavity to different brain areas. Here, we discuss how different technological approaches enhance this N-to-B transport, with emphasis on those that have shown a potential for clinical translation. We also analyse how the physicochemical properties of nanocarriers and their modification with cell-penetrating peptides (CPPs) and targeting ligands affect their efficacy as N-to-B carriers for biomolecules.

RNA cancer nanomedicine: nanotechnology-mediated RNA therapy

It has been demonstrated that RNA molecules-mRNA, siRNA, microRNA, and sgRNA-regulate cancer-specific genes, and therefore, RNA-based therapeutics can suppress tumor progression and metastasis by selectively upregulating and silencing these genes. However, the innate defense mechanisms (e.g., exonucleases and RNases) involving the human immune system catalyze the degradation of exogenous RNAs. Thus, nonviral nanoparticles have been employed to deliver therapeutic RNAs for effective cancer gene therapy. In this minireview, we highlight efforts in the past decade to deliver therapeutic RNAs for cancer therapy using novel nanoparticles. Specifically, we review nanoparticles, including lipid, polymer, inorganic, and biomimetic materials, which have been employed to deliver therapeutic RNAs and evoke tumor suppressing responses. Finally, we discuss the challenges and considerations that may accelerate the clinical translation of nanotechnology-mediated RNA therapy.

Gold nanostructures: synthesis, properties, and neurological applications

Recent advances in technology are expected to increase our current understanding of neuroscience. Nanotechnology and nanomaterials can alter and control neural functionality in both in vitro and in vivo experimental setups. The intersection between neuroscience and nanoscience may generate long-term neural interfaces adapted at the molecular level. Owing to their intrinsic physicochemical characteristics, gold nanostructures (GNSs) have received much attention in neuroscience, especially for combined diagnostic and therapeutic (theragnostic) purposes. GNSs have been successfully employed to stimulate and monitor neurophysiological signals. Hence, GNSs could provide a promising solution for the regeneration and recovery of neural tissue, novel neuroprotective strategies, and integrated implantable materials. This review covers the broad range of neurological applications of GNS-based materials to improve clinical diagnosis and therapy. Sub-topics include neurotoxicity, targeted delivery of therapeutics to the central nervous system (CNS), neurochemical sensing, neuromodulation, neuroimaging, neurotherapy, tissue engineering, and neural regeneration. It focuses on core concepts of GNSs in neurology, to circumvent the limitations and significant obstacles of innovative approaches in neurobiology and neurochemistry, including theragnostics. We will discuss recent advances in the use of GNSs to overcome current bottlenecks and tackle technical and conceptual challenges.

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

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

Nanoscale Drug Delivery Systems in Glioblastoma

Glioblastoma is the most aggressive cerebral tumor in adults. However, the current pharmaceuticals in GBM treatment are mainly restricted to few chemotherapeutic drugs and have limited efficacy. Therefore, various nanoscale biomaterials that possess distinct structure and unique property were constructed as vehicles to precisely deliver molecules with potential therapeutic effect. In this review, nanoparticle drug delivery systems including CNTs, GBNs, C-dots, MOFs, Liposomes, MSNs, GNPs, PMs, Dendrimers and Nanogel were exemplified. The advantages and disadvantages of these nanoparticles in GBM treatment were illustrated.

The Yin and Yang of epigenetics in the field of nanoparticles

Nanoparticles (NPs) have become a very exciting research avenue, with multitudinous applications in various fields, including the biomedical one, whereby they have been gaining considerable interest as drug carriers able to increase bioavailability, therapeutic efficiency and specificity of drugs. Epigenetics, a complex network of molecular mechanisms involved in gene expression regulation, play a key role in mediating the effect of environmental factors on organisms and in the etiology of several diseases (e.g., cancers, neurological disorders and cardiovascular diseases). For many of these diseases, epigenetic therapies have been proposed, whose application is however limited by the toxicity of epigenetic drugs. In this review, we will analyze two aspects of epigenetics in the field of NPs: the first is the role that epigenetics play in mediating nanotoxicity, and the second is the possibility of using NPs for delivery of "epi-drugs" to overcome their limitations. We aim to stimulate discussion among specialists, specifically on the potential contribution of epigenetics to the field of NPs, and to inspire newcomers to this exciting technology.

Nose-to-brain delivery of simvastatin mediated by chitosan-coated lipid-core nanocapsules allows for the treatment of glioblastoma in vivo

Glioblastoma is the most common and lethal malignant brain tumor. Despite simvastatin (SVT) showing potential anticancer properties, its antitumoral effect against glioblastoma appears limited when the conventional oral administration route is selected. As a consequence, nose-to-brain delivery has been proposed as an alternative route to deliver SVT into the brain. This study aimed to prepare chitosan-coated simvastatin-loaded lipid-core nanocapsules (LNC_SVT-chit) suitable for nose-to-brain delivery and capable of fostering antitumor effects against glioblastoma both in vitro and in vivo. Results showed that the nanocapsules present adequate particle size (mean diameter below 200 nm), narrow particle size distribution (PDI < 0.2), positive zeta potential and high encapsulation efficiency (nearly 100%). In vitro cytotoxicity of LNC_SVT-chit was comparable to non-encapsulated SVT in C6 rat glioma cells, whereas LNC_SVT-chit were more cytotoxic than non-encapsulated SVT after 72 h of incubation against U-138 MG human glioblastoma cell line. In studies carried out in rats, LNC_SVT-chit significantly enhanced the amount of drug in rat brain tissue after intranasal administration (2.4-fold) when compared with free SVT. Moreover, LNC_SVT-chit promoted a significant decrease in tumor growth and malignancy in glioma-bearing rats in comparison to control and free SVT groups. Additionally, LNC_SVT-chit did not cause any toxicity in treated rats. Considered overall, the results demonstrated that the nose-to-brain administration of LNC_SVT-chit represents a novel potential strategy for glioblastoma treatment.

A review of recent advances in magnetic nanoparticle-based theranostics of glioblastoma

Rapid vascular growth, infiltrative cells and high tumor heterogenicity are some glioblastoma multiforme (GBM) characteristics, making it the most lethal form of brain cancer. Low efficacy of the conventional treatment modalities leads to rampant disease progression and a median survival of 15 months. Magnetic nanoparticles (MNPs), due to their unique physical features/inherent abilities, have emerged as a suitable theranostic platform for targeted GBM treatment. Thus, new strategies are being designed to enhance the efficiency of existing therapeutic techniques such as chemotherapy, radiotherapy, and so on, using MNPs. Herein, the limitations of the current therapeutic strategies, the role of MNPs in mitigating those inadequacies, recent advances in the MNP-based theranostics of GBM and possible future directions are discussed.

Ultrasound-Guided Microbubble-Mediated Locoregional Delivery of Multiple MicroRNAs Improves Chemotherapy in Hepatocellular Carcinoma

Rationale: To assess treatment effects of 4 complementary miRNAs (miRNA-100/miRNA-122/antimiRNA-10b/antimiRNA-21) encapsulated in a biodegradable PLGA-PEG nanoparticle, administered by an ultrasound-guided microbubble-mediated targeted delivery (UGMMTD) approach in mouse models of hepatocellular carcinoma (HCC). Methods:In vitro apoptotic index was measured in HepG2 and Hepa1-6 HCC cells treated with various combinations of the 4 miRNAs with doxorubicin. Three promising combinations were further tested in vivo by using UGMMTD. 63 HepG2 xenografts in mice were randomized into: group 1, miRNA-122/antimiRNA-10b/antimiRNA-21/US/doxorubicin; group 2, miRNA-100/miRNA-122/antimiRNA-10b/antimiRNA-21/US/doxorubicin; group 3, miRNA-100/miRNA-122/antimiRNA-10b/US/doxorubicin; group 4, miRNA-122/anitmiRNA-10b/antimiRNA-21/doxorubicin; group 5, miRNA-100/miRNA-122/antimiRNA-10b/antimiRNA-21/doxorubicin; group 6, miRNA-100/miRNA-122/antimiRNA-10b/doxorubicin; group 7, doxorubicin only treatment; and group 8, without any treatment. Tumor volumes were measured through 18 days. H&E staining, TUNEL assay, and qRT-PCR quantification for delivered miRNAs were performed. Results:In vivo results showed that UGMMTD of miRNAs with doxorubicin in groups 1-3 significantly (P<0.05) delayed tumor growth compared to control without any treatment, and doxorubicin only from day 7 to 18. On qRT-PCR, levels of delivered miRNAs were significantly (P<0.05) higher in groups 1-3 upon UGMMTD treatment compared to controls. TUNEL assay showed that upon UGMMTD, significantly higher levels of apoptotic cell populations were observed in groups 1-3 compared to controls. Toxicity was not observed in various organs of different groups. Conclusions: UGMMTD of miRNA-100/miRNA-122/antimiRNA-10b/antimiRNA-21 combination improved therapeutic outcome of doxorubicin chemotherapy in mouse models of HCC by substantial inhibition of tumor growth and significant increase in apoptotic index.

Functionalized Nanomaterials as Tailored Theranostic Agents in Brain Imaging

Functionalized nanomaterials of various categories are essential for developing cancer nano-theranostics for brain diseases; however, some limitations exist in their effectiveness and clinical translation, such as toxicity, limited tumor penetration, and inability to cross blood-brain and blood-tumor barriers. Metal nanomaterials with functional fluorescent tags possess unique properties in improving their functional properties, including surface plasmon resonance (SPR), superparamagnetism, and photo/bioluminescence, which facilitates imaging applications in addition to their deliveries. Moreover, these multifunctional nanomaterials could be synthesized through various chemical modifications on their physical surfaces via attaching targeting peptides, fluorophores, and quantum dots (QD), which could improve the application of these nanomaterials by facilitating theranostic modalities. In addition to their inherent CT (Computed Tomography), MRI (Magnetic Resonance Imaging), PAI (Photo-acoustic imaging), and X-ray contrast imaging, various multifunctional nanoparticles with imaging probes serve as brain-targeted imaging candidates in several imaging modalities. The primary criteria of these functional nanomaterials for translational application to the brain must be zero toxicity. Moreover, the beneficial aspects of nano-theranostics of nanoparticles are their multifunctional systems proportioned towards personalized disease management via comprising diagnostic and therapeutic abilities in a single biodegradable nanomaterial. This review highlights the emerging aspects of engineered nanomaterials to reach and deliver therapeutics to the brain and how to improve this by adopting the imaging modalities for theranostic applications.

Drug Delivery Systems and Strategies to Overcome the Barriers of Brain

The transport of drugs to the central nervous system is the most challenging task for conventional drug delivery systems. Reduced permeability of drugs through the blood-brain barrier is a major hurdle in delivering drugs to the brain. Hence, various strategies for improving drug delivery through the blood-brain barrier are currently being explored. Novel drug delivery systems (NDDS) offer several advantages, including high chemical and biological stability, suitability for both hydrophobic and hydrophilic drugs, and can be administered through different routes. Furthermore, the conjugation of suitable ligands with these carriers tend to potentiate targeting to the endothelium of the brain and could facilitate the internalization of drugs through endocytosis. Further, the intranasal route has also shown potential, as a promising alternate route, for the delivery of drugs to the brain. This can deliver the drugs directly to the brain through the olfactory pathway. In recent years, several advancements have been made to target and overcome the barriers of the brain. This article deals with a detailed overview of the diverse strategies and delivery systems to overcome the barriers of the brain for effective delivery of drugs.

Cyclodextrin-Modified Nanomaterials for Drug Delivery: Classification and Advances in Controlled Release and Bioavailability

In drug delivery, one widely used way of overcoming the biopharmaceutical problems present in several active pharmaceutical ingredients, such as poor aqueous solubility, early instability, and low bioavailability, is the formation of inclusion compounds with cyclodextrins (CD). In recent years, the use of CD derivatives in combination with nanomaterials has shown to be a promising strategy for formulating new, optimized systems. The goals of this review are to give in-depth knowledge and critical appraisal of the main CD-modified or CD-based nanomaterials for drug delivery, such as lipid-based nanocarriers, natural and synthetic polymeric nanocarriers, nanosponges, graphene derivatives, mesoporous silica nanoparticles, plasmonic and magnetic nanoparticles, quantum dots and other miscellaneous systems such as nanovalves, metal-organic frameworks, Janus nanoparticles, and nanofibers. Special attention is given to nanosystems that achieve controlled drug release and increase their bioavailability during in vivo studies.

Blood-Brain Barrier in Brain Tumors: Biology and Clinical Relevance

The presence of barriers, such as the blood–brain barrier (BBB) and brain–tumor barrier (BTB), limits the penetration of antineoplastic drugs into the brain, resulting in poor response to treatments. Many techniques have been developed to overcome the presence of these barriers, including direct injections of substances by intranasal or intrathecal routes, chemical modification of drugs or constituents of BBB, inhibition of efflux pumps, physical disruption of BBB by radiofrequency electromagnetic radiation (EMP), laser-induced thermal therapy (LITT), focused ultrasounds (FUS) combined with microbubbles and convection enhanced delivery (CED). However, most of these strategies have been tested only in preclinical models or in phase 1–2 trials, and none of them have been approved for treatment of brain tumors yet. Concerning the treatment of brain metastases, many molecules have been developed in the last years with a better penetration across BBB (new generation tyrosine kinase inhibitors like osimertinib for non-small-cell lung carcinoma and neratinib/tucatinib for breast cancer), resulting in better progression-free survival and overall survival compared to older molecules. Promising studies concerning neural stem cells, CAR-T (chimeric antigen receptors) strategies and immunotherapy with checkpoint inhibitors are ongoing.

A Microfluidics-Based Scalable Approach to Generate Extracellular Vesicles with Enhanced Therapeutic MicroRNA Loading for Intranasal Delivery to Mouse Glioblastomas

Extracellular vesicles (EVs), including exosomes and microvesicles derived from different cell sources, are used as promising nanovesicles for delivering therapeutic microRNAs (miRNAs) and drugs in cancer therapy. However, their clinical translation is limited by the quantity, size heterogeneity, and drug or small RNA loading efficiency. Herein, we developed a scalable microfluidic platform that can load therapeutic miRNAs (antimiRNA-21 and miRNA-100) and drugs while controlling the size of microfluidically processed EVs (mpEVs) using a pressure-based disruption and reconstitution process. We prepared mpEVs of optimal size using microvesicles isolated from neural stem cells engineered to overexpress CXCR4 receptor and characterized them for charge and miRNA loading efficiency. Since the delivery of therapeutic miRNAs to brain cancer is limited by the blood-brain barrier (BBB), we adopted intranasal administration of miRNA-loaded CXCR4-engineered mpEVs in orthotopic GBM mouse models and observed a consistent pattern of mpEVs trafficking across the nasal epithelia, bypassing the BBB into the intracranial compartment. In addition, the CXCR4-engineered mpEVs manifested selective tropism toward GBMs by stromal-derived factor-1 chemotaxis to deliver their miRNA cargo. The delivered miRNAs sensitized GBM cells to temozolomide, resulting in prominent tumor regression, and improved the overall survival of mice. A simple and efficient approach of packaging miRNAs in mpEVs using microfluidics, combined with a noninvasive nose-to-brain delivery route presents far-reaching potential opportunities to improve GBM therapy in clinical practice.

Gold-Nanostar-Chitosan-Mediated Delivery of SARS-CoV-2 DNA Vaccine for Respiratory Mucosal Immunization: Development and Proof-of-Principle

The COVID-19 pandemic is caused by the coronavirus SARS-CoV-2 (SC2). A variety of anti-SC2 vaccines have been approved for human applications, including those using messenger RNA (mRNA), adenoviruses expressing SC2 spike (S) protein, and inactivated virus. The protective periods of immunization afforded by these intramuscularly administered vaccines are currently unknown. An alternative self-administrable vaccine capable of mounting long-lasting immunity via sterilizing neutralizing antibodies would be hugely advantageous in tackling emerging mutant SC2 variants. This could also diminish the possibility of vaccinated individuals acting as passive carriers of COVID-19. Here, we investigate the potential of an intranasal (IN)-delivered DNA vaccine encoding the S protein of SC2 in BALB/c and C57BL/6J immunocompetent mouse models. The immune response to IN delivery of this SC2-spike DNA vaccine transported on a modified gold-chitosan nanocarrier shows a strong and consistent surge in antibodies (IgG, IgA, and IgM) and effective neutralization of pseudoviruses expressing S proteins of different SC2 variants (Wuhan, beta, and D614G). Immunophenotyping and histological analyses reveal chronological events involved in the recognition of SC2 S antigen by resident dendritic cells and alveolar macrophages, which prime the draining lymph nodes and spleen for peak SC2-specific cellular and humoral immune responses. The attainable high levels of anti-SC2 IgA in lung mucosa and tissue-resident memory T cells can efficiently inhibit SC2 and its variants at the site of entry and also provide long-lasting immunity.

Brain Delivery of Curcumin Through Low-Intensity Ultrasound-Induced Blood-Brain Barrier Opening via Lipid-PLGA Nanobubbles

Background

Parkinson's disease (PD) is a progressive neurodegenerative disorder. Owing to the presence of blood-brain barrier (BBB), conventional pharmaceutical agents are difficult to the diseased nuclei and exert their action to inhibit or delay the progress of PD. Recent literatures have demonstrated that curcumin shows the great potential to treat PD. However, its applications are still difficult in vivo due to its poor druggability and low bioavailability through the BBB.

Methods

Melt-crystallization methods were used to improve the solubility of curcumin, and curcumin-loaded lipid-PLGA nanobubbles (Cur-NBs) were fabricated through encapsulating the curcumin into the cavity of lipid-PLGA nanobubbles. The bubble size, zeta potentials, ultrasound imaging capability and drug encapsulation efficiency of the Cur-NBs were characterized by a series of analytical methods. Low-intensity focused ultrasound (LIFU) combined with Cur-NB was used to open the BBB to facilitate curcumin delivery into the deep brain of PD mice, followed by behavioral evaluation for the treatment efficacy.

Results

The solubility of curcumin was improved by melt-crystallization methods, with 2627-fold higher than pure curcumin. The resulting Cur-NBs have a nanoscale size about 400 nm and show excellent contrast imaging performance. Curcumin drugs encapsulated into Cur-NBs could be effectively released when Cur-NBs were irradiated by LIFU at the optimized acoustic pressure, achieving 30% cumulative release rate within 6 h. Importantly, Cur-NBs combined with LIFU can open the BBB and locally deliver the curcumin into the deep-seated brain nuclei, significantly enhancing efficacy of curcumin in the Parkinson C57BL/6J mice model in comparison with only Cur-NBs and LIFU groups.

Conclusion

In this work, we greatly improved the solubility of curcumin and developed Cur-NBs for brain delivery of curcumin against PD through combining with LIFU-mediating BBB. Cur-NBs provide a platform for these potential drugs which are difficult to cross the BBB to treat PD disease or other central nervous system (CNS) diseases.

miRNA Delivery by Nanosystems: State of the Art and Perspectives

MicroRNAs (miRNAs) are short (~21-23 nucleotides), non-coding endogenous RNA molecules that modulate gene expression at the post-transcriptional level via the endogenous RNA interference machinery of the cell. They have emerged as potential biopharmaceuticals candidates for the treatment of various diseases, including cancer, cardiovascular and metabolic diseases. However, in order to advance miRNAs therapeutics into clinical settings, their delivery remains a major challenge. Different types of vectors have been investigated to allow the delivery of miRNA in the diseased tissue. In particular, non-viral delivery systems have shown important advantages such as versatility, low cost, easy fabrication and low immunogenicity. Here, we present a general overview of the main types of non-viral vectors developed for miRNA delivery, with their advantages, limitations and future perspectives.

microRNA-based diagnostic and therapeutic applications in cancer medicine

It has been almost two decades since the first link between microRNAs and cancer was established. In the ensuing years, this abundant class of short noncoding regulatory RNAs has been studied in virtually all cancer types. This tremendously large body of research has generated innovative technological advances for detection of microRNAs in tissue and bodily fluids, identified the diagnostic, prognostic, and/or predictive value of individual microRNAs or microRNA signatures as potential biomarkers for patient management, shed light on regulatory mechanisms of RNA-RNA interactions that modulate gene expression, uncovered cell-autonomous and cell-to-cell communication roles of specific microRNAs, and developed a battery of viral and nonviral delivery approaches for therapeutic intervention. Despite these intense and prolific research efforts in preclinical and clinical settings, there are a limited number of microRNA-based applications that have been incorporated into clinical practice. We review recent literature and ongoing clinical trials that highlight most promising approaches and standing challenges to translate these findings into viable microRNA-based clinical tools for cancer medicine. This article is categorized under: RNA in Disease and Development > RNA in Disease.

Nanoparticles modified with vasculature-homing peptides for targeted cancer therapy and angiogenesis imaging

The two major challenges in cancer treatment include lack of early detection and ineffective therapies with various side effects. Angiogenesis is the key process in the growth, survival, invasiveness, and metastasis of many of cancerous tumors. Imaging of the angiogenesis could lead to diagnosis of tumors in the early stage and evaluation of the therapeutic responses. Angiogenic blood vessels express specific molecular markers different from normal blood vessels (in level or kind). This fact would make the tumor vasculature a suitable site to target therapeutics and imaging agents within the tumor. Surface modified nanoparticles using peptide ligands with high binding affinity to the vasculature markers, provide efficient delivery of therapeutic and imaging agents, while avoiding undesirable side effects. In this review, we discuss discoveries of various tumor targeting peptides useful for tumor angiogenesis imaging and targeted therapy with emphasis on surface modified nanomedicines using vasculature targeting peptides.

Nanotechnology-Assisted RNA Delivery: From Nucleic Acid Therapeutics to COVID-19 Vaccines

In recent years, the main quest of science has been the pioneering of the groundbreaking biomedical strategies needed for achieving a personalized medicine. Ribonucleic acids (RNAs) are outstanding bioactive macromolecules identified as pivotal actors in regulating a wide range of biochemical pathways. The ability to intimately control the cell fate and tissue activities makes RNA-based drugs the most fascinating family of bioactive agents. However, achieving a widespread application of RNA therapeutics in humans is still a challenging feat, due to both the instability of naked RNA and the presence of biological barriers aimed at hindering the entrance of RNA into cells. Recently, material scientists' enormous efforts have led to the development of various classes of nanostructured carriers customized to overcome these limitations. This work systematically reviews the current advances in developing the next generation of drugs based on nanotechnology-assisted RNA delivery. The features of the most used RNA molecules are presented, together with the development strategies and properties of nanostructured vehicles. Also provided is an in-depth overview of various therapeutic applications of the presented systems, including coronavirus disease vaccines and the newest trends in the field. Lastly, emerging challenges and future perspectives for nanotechnology-mediated RNA therapies are discussed.

Nanoprobe-mediated precise imaging and therapy of glioma

Gliomas are the most common primary brain tumors in adults, accounting for 80% of primary intracranial tumors. Due to the heterogeneous and infiltrating nature of malignant gliomas and the hindrance of the blood-brain barrier (BBB), it is very difficult to accurately image and differentiate the malignancy grade of gliomas, thus significantly influencing the diagnostic accuracy and subsequent surgery or therapy. In recent years, the rapid development of emerging nanoprobes has provided a promising opportunity for the diagnosis and treatment of gliomas. After rational component regulation and surface modification, functional nanoprobes could efficiently cross the BBB, target gliomas, and realize single-modal or multimodal imaging of gliomas with high clarity. Moreover, these contrast nanoagents could also be conjugated with therapeutic drugs and cure cancerous tissues at the same time. Herein, we focus on the design strategies of nanoprobes for effective crossing of the BBB, and introduce the recent advances in the precise imaging and therapy of gliomas using functional nanoprobes. Finally, we also discuss the challenges and future directions of nanoprobe-based diagnosis and treatment of gliomas.

Nanotechnologies for intranasal drug delivery: an update of literature

Scientific research has focused its attention on finding an alternative route to systemic oral and parenteral administration, to overcome their usual drawbacks, such as hepatic first-pass which decreases drug bioavailability after oral administration, off-target effects, low patient compliance and low speed of onset of the pharmacological action in first-aid cases. Innovative drug delivery systems (DDS), mainly based on polymer and lipid biocompatible materials, have given a great prompt in this direction in the last years. The intranasal (IN) route of administration is a valid non-invasive alternative. It is highly suitable for self-administration, the drug quickly reaches the bloodstream, largely avoiding the first pass effect, and can also reach directly the brain bypassing BBB. Association of IN route with DDS can thus become a winning strategy for the controlled delivery of drugs, especially when a very quick effect is desired or needed. This review aims at analyzing the scientific literature regarding IN-DDS and their different ways of administration (systemic, topical, pulmonary, nose-to-brain). In particular, attention was devoted to polymer- and lipid-based micro- and nanocarriers, being the topic of most published articles in the last decade, but the whole plethora of colloidal DDS investigated in recent years for IN administration was presented.

Temozolomide nano enabled medicine: promises made by the nanocarriers in glioblastoma therapy

Glioblastoma multiforme (GBM) is abnormal cell proliferation of glial cells. GBM is the grade IV glioma brain cancer which is life-threatening to many individuals affected by this cancer. The DNA alkylating agent Temozolomide (TMZ) has the distinctiveness of being FDA approved anticancer drug for the first line treatment for GBM. However, treatment of GBM still remains a challenge. This is attributed to TMZ's toxic nature, severe side effects, and fast degradation in vivo. In addition, the lack of targeting ability increases the chances of systemic toxicities. A nano enabled targeted delivery system not only improves the efficiency of TMZ by making it cross the blood brain barrier, have specificity to target, but also reduces toxicity to healthy tissues. Over the last decade the significant advances in the area of nanotechnology applied to medicine have developed many multifunctional therapeutics. In this context, the present review article comprehends the significant progress in the field of TMZ loaded nanocarriers showing promise for futuristic nanomedicine therapies in treating GBM.

MicroRNA Therapeutics in Cancer: Current Advances and Challenges

Simple Summary

Cancer is a complex disease associated with deregulation of numerous genes. In addition, redundant cellular pathways limit efficiency of monotarget drugs in cancer therapy. MicroRNAs are a class of gene expression regulators, which often function by targeting multiple genes. This feature makes them a double-edged sword (a) as attractive targets for anti-tumor therapy and concomitantly (b) as risky targets due to their potential side effects on healthy tissues. As for conventional antitumor drugs, nanocarriers have been developed to circumvent the problems associated with miRNA delivery to tumors. In this review, we highlight studies that have established the pre-clinical proof-of concept of miRNAs as relevant therapeutic targets in oncology. Particular attention was brought to new strategies based on nanovectorization of miRNAs as well as to the perspectives for their applications.

Abstract

The discovery of microRNAs (miRNAs) in 1993 has challenged the dogma of gene expression regulation. MiRNAs affect most of cellular processes from metabolism, through cell proliferation and differentiation, to cell death. In cancer, deregulated miRNA expression leads to tumor development and progression by promoting acquisition of cancer hallmark traits. The multi-target action of miRNAs, which enable regulation of entire signaling networks, makes them attractive tools for the development of anti-cancer therapies. Hence, supplementing downregulated miRNA by synthetic oligonucleotides or silencing overexpressed miRNAs through artificial antagonists became a common strategy in cancer research. However, the ultimate success of miRNA therapeutics will depend on solving pharmacokinetic and targeted delivery issues. The development of a number of nanocarrier-based platforms holds significant promises to enhance the cell specific controlled delivery and safety profile of miRNA-based therapies. In this review, we provide among the most comprehensive assessments to date of promising nanomedicine platforms that have been tested preclinically, pertaining to the treatment of selected solid tumors including lung, liver, breast, and glioblastoma tumors as well as endocrine malignancies. The future challenges and potential applications in clinical oncology are discussed.

Combinatorial miRNA-34a replenishment and irinotecan delivery via auto-fluorescent polymeric hybrid micelles for synchronous colorectal cancer theranostics

The synergistic combination of microRNA (miRNA) modulation and chemotherapy has emerged as an effective strategy to combat cancer. Irinotecan (IRI) is a potent antitumor chemotherapeutic in clinical practice and has been used for treating various malignant tumors, including colorectal cancer (CRC). However, IRI is not effective for advanced CRC or metastatic behavior. Herein, novel polymeric hybrid micelles were engineered based on two different amphiphilic copolymers, polyethyleneimine-poly(d,l-lactide) (PEI-PLA) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethyleneglycol) (DSPE-PEG), in which IRI and a tumor suppressive microRNA-34a (miR-34a) gene were efficiently co-loaded (MINPs) to achieve a chemo-miRNA combination therapy against CRC. MINPs were successfully constructed by two-step film dispersion and electrostatic interaction methods. IRI and miR-34a could be efficaciously encapsulated as MINPs and transferred to CRC cells. After encapsulation, MINPs would then upregulate miR-34a expression and regulate miR-34a-related downstream genes, which in turn led to enhanced cell cytotoxicity and apoptosis ratios. MINPs presented an excitation-dependent multi-wavelength emission feature due to the intrinstic fluorescence properties of PEI-PLA and could be utilized for in vitro/vivo imaging. According to the in vivo experimental results, MINPs possess the great characteristic of accumulating in situ in a tumor site and lightening it after intravenous administration. Furthermore, MINPs presented extraordinary antitumor efficacy owing to the combined therapy effects of IRI and miR-34a with good biocompability. Overall, our findings validated MINPs-mediated miR-34a replenishment and IRI co-delivery to serve as an effective theranostic platform and provided an innovative horizon for combining chemo-gene therapy against CRC.

Construction of nanomaterials as contrast agents or probes for glioma imaging

Malignant glioma remains incurable largely due to the aggressive and infiltrative nature, as well as the existence of blood-brain-barrier (BBB). Precise diagnosis of glioma, which aims to accurately delineate the tumor boundary for guiding surgical resection and provide reliable feedback of the therapeutic outcomes, is the critical step for successful treatment. Numerous imaging modalities have been developed for the efficient diagnosis of tumors from structural or functional aspects. However, the presence of BBB largely hampers the entrance of contrast agents (Cas) or probes into the brain, rendering the imaging performance highly compromised. The development of nanomaterials provides promising strategies for constructing nano-sized Cas or probes for accurate imaging of glioma owing to the BBB crossing ability and other unique advantages of nanomaterials, such as high loading capacity and stimuli-responsive properties. In this review, the recent progress of nanomaterials applied in single modal imaging modality and multimodal imaging for a comprehensive diagnosis is thoroughly summarized. Finally, the prospects and challenges are offered with the hope for its better development.