Innovative nanotechnologies for the delivery of oligonucleotides and siRNA

Therapeutic Implications of Dietary Polyphenols-Loaded Nanoemulsions in Cancer Therapy

Cancer is one of the major causes of death worldwide, even the second foremost cause related to non-communicable diseases. Cancer cells typically possess several cellular and biological processes including, persistence, propagation, differentiation, cellular death, and expression of cellular-type specific functions. The molecular picture of carcinogenesis and progression is unwinding, and it appears to be a tangled combination of processes occurring within and between cancer cells and their surrounding tissue matrix. Polyphenols are plant secondary metabolites abundant in fruits, vegetables, cereals, and other natural plant sources. Natural polyphenols have implicated potential anticancer activity by various mechanisms involved in their antitumor action, including modulation of signaling pathways majorly related to cellular proliferation, differentiation, relocation, angiogenesis, metastatic processes, and cell death. The applications of polyphenols have been limited due to the hydrophobic nature and lower oral bioavailability that could be possibly overcome through encapsulating them into nanocarrier-mediated delivery systems, leading to improved anticancer activity. Nanoemulsions (NEs) possess diverse feasible properties, including greater surface area, modifiable surficial charge, higher half-life, site-specific targeting, and formulation imaging capability necessary to create a practical therapeutic impact, and have drawn increased attention in cancer therapy research. This review has summarized and discussed the basic concepts, classification, delivery approaches, and anticancer mechanism of various polyphenols and polyphenols-encapsulated nanoemulsions with improved cancer therapy.

Nanomedicine-based delivery strategies for nucleic acid gene inhibitors in inflammatory diseases

Thanks to their abilities to modulate the expression of virtually any genes, RNA therapeutics have attracted considerable research efforts. Among the strategies focusing on nucleic acid gene inhibitors, antisense oligonucleotides and small interfering RNAs have reached advanced clinical trial phases with several of them having recently been marketed. These successes were obtained by overcoming stability and cellular delivery issues using either chemically modified nucleic acids or nanoparticles. As nucleic acid gene inhibitors are promising strategies to treat inflammatory diseases, this review focuses on the barriers, from manufacturing issues to cellular/subcellular delivery, that still need to be overcome to deliver the nucleic acids to sites of inflammation other than the liver. Furthermore, key examples of applications in rheumatoid arthritis, inflammatory bowel, and lung diseases are presented as case studies of systemic, oral, and lung nucleic acid delivery.

Emerging Applications of Nanotechnology in Healthcare Systems: Grand Challenges and Perspectives

Healthcare, as a basic human right, has often become the focus of the development of innovative technologies. Technological progress has significantly contributed to the provision of high-quality, on-time, acceptable, and affordable healthcare. Advancements in nanoscience have led to the emergence of a new generation of nanostructures. Each of them has a unique set of properties that account for their astonishing applications. Since its inception, nanotechnology has continuously affected healthcare and has exerted a tremendous influence on its transformation, contributing to better outcomes. In the last two decades, the world has seen nanotechnology taking steps towards its omnipresence and the process has been accelerated by extensive research in various healthcare sectors. The inclusion of nanotechnology and its allied nanocarriers/nanosystems in medicine is known as nanomedicine, a field that has brought about numerous benefits in disease prevention, diagnosis, and treatment. Various nanosystems have been found to be better candidates for theranostic purposes, in contrast to conventional ones. This review paper will shed light on medically significant nanosystems, as well as their applications and limitations in areas such as gene therapy, targeted drug delivery, and in the treatment of cancer and various genetic diseases. Although nanotechnology holds immense potential, it is yet to be exploited. More efforts need to be directed to overcome these limitations and make full use of its potential in order to revolutionize the healthcare sector in near future.

Combining dexamethasone and TNF-α siRNA within the same nanoparticles to enhance anti-inflammatory effect

We propose to combine two therapeutic anti-inflammatory approaches with different mechanisms of action in a single drug delivery system consisting of cationic dexamethasone palmitate nanoparticles (CDXP-NP) associated with TNF-α siRNA. The CDXP-NPs are obtained by the solvent emulsion evaporation technique using dexamethasone palmitate, a prodrug of dexamethasone, associated with a cationic lipid, DOTAP. Their physicochemical properties as well as their ability to bind siRNA were evaluated through gel electrophoresis and siRNA binding quantification. SiRNA cellular uptake was assessed by flow cytometry and confocal microscopy on RAW264.7 macrophages. TNF-α inhibition was determined on LPS-activated RAW264.7 macrophages. Stable and monodisperse nanoparticles around 100 nm with a positive zeta potential (+59 mV) were obtained with an encapsulation efficiency of the prodrug of 95%. A nitrogen/phosphate (N/P) ratio of 10 was selected that conferred the total binding of siRNA to the nanoparticles. Using these CDXP-siRNA-NPs, the siRNA was strongly internalized by RAW264.7 macrophage cells and localized within the cytoplasm. On the LPS-induced RAW264.7 macrophages, a larger inhibition of TNF-α was observed with CDXP-siRNA-NPs compared to CDXP-NPs alone. In conclusion, from these data, it is clear that a combination of DXP and TNF-α siRNA therapy could be a novel strategy and optimized alternative approach to cure inflammatory diseases.

Nanotechnology Enabled Solutions to Combat Covid-19: Prevention, Treatment and Diagnosis

Changes in human lifestyles and environmental deterioration globally causes emergence of new viruses posing research challenges. Recent outburst of disease COVID-19 (nCoV19) is a recent example wherein effective management of virus using conventional medication or adopting preventive and effective diagnostic measures is a challenge. While many ongoing strategies from vaccine development to drug repurposing, are currently being investigated, a targeted approach with nanotechnology can be helpful to meet the demand for preventive and diagnostic measures. The significant results of nanotechnology in resolving better efficacy in pharmaceutical drugs is expected to be helpful in combating nCoV19 by using nanotechnology-based solutions preventive, treatment, and diagnosis. As vaccine development involves long clinical trial procedures, preventive measures such as masks, disinfectants, sanitizers, and personal protective equipment's are gaining popularity for effective management. The present write-up addresses the dire need of the nanotechnology-based solutions in present pandemic and studies of the ongoing innovation and existing patents for developing better solutions. Multiple applications of nanotechnology is expected to be helpful in preventive and diagnostic measures, immune response modulation and immunity boosters along with projecting a pathway for industry and academic researchers for addressing such pandemic.

Current Applications of Nanoemulsions in Cancer Therapeutics

Nanoemulsions are pharmaceutical formulations composed of particles within a nanometer range. They possess the capacity to encapsulate drugs that are poorly water soluble due to their hydrophobic core nature. Additionally, they are also composed of safe gradient excipients, which makes them a stable and safe option to deliver drugs. Cancer therapy has been an issue for several decades. Drugs developed to treat this disease are not always successful or end up failing, mainly due to low solubility, multidrug resistance (MDR), and unspecific toxicity. Nanoemulsions might be the solution to achieve efficient and safe tumor treatment. These formulations not only solve water-solubility problems but also provide specific targeting to cancer cells and might even be designed to overcome MDR. Nanoemulsions can be modified using ligands of different natures to target components present in tumor cells surface or to escape MDR mechanisms. Multifunctional nanoemulsions are being studied by a wide variety of researchers in different research areas mainly for the treatment of different types of cancer. All of these studies demonstrate that nanoemulsions are efficiently taken by the tumoral cells, reduce tumor growth, eliminate toxicity to healthy cells, and decrease migration of cancer cells to other organs.

A journey through the emergence of nanomedicines with poly(alkylcyanoacrylate) based nanoparticles

Starting in the late 1970s, the pioneering work of Patrick Couvreur gave birth to the first biodegradable nanoparticles composed of a biodegradable synthetic polymer. These nanoparticles, made of poly(alkylcyanoacrylate) (PACA), were the first synthetic polymer-based nanoparticulate drug carriers undergoing a phase III clinical trial so far. Analyzing the journey from the birth of PACA nanoparticles to their clinical evaluation, this paper highlights their remarkable adaptability to bypass various drug delivery challenges found on the way. At present, PACA nanoparticles include a wide range of nanoparticles that can associate drugs of different chemical nature and can be administered in vivo by different routes. The most recent technologies giving the nanoparticles customised functions could also be implemented on this family of nanoparticles. Through different examples, this paper discusses the seminal role of the PACA nanoparticles' family in the development of nanomedicines.

Delivery of Small Interfering RNA. A Review and an Example of Application to a Junction Oncogene

RNA interference strategies using small interfering RNA is one of the most important discoveries in biology in recent years. This technology alongside antisense oligonucleotides is very promising and our group has focused its work on the targeting of junction oncogenes with these molecules. We have taken, as first example, papillary thyroid carcinoma. But there is a great need in delivery methods for these molecules in the treatment of cancers. Indeed, many studies have shown that small interfering RNA and antisense oligonucleotides are made efficient by various innovative delivery methods and, under these conditions, offer a powerful new therapeutic tool in cancer treatment.

Subcellular co-delivery of two different site-oriented payloads based on multistage targeted polymeric nanoparticles for enhanced cancer therapy

Smart nanoparticles which encapsulated two different site-oriented therapeutic agents for multistage targeted delivery and enhanced antitumor therapy.

The role of nanotechnology in the treatment of viral infections

Infectious diseases are the leading cause of mortality worldwide, with viruses in particular making global impact on healthcare and socioeconomic development. In addition, the rapid development of drug resistance to currently available therapies and adverse side effects due to prolonged use is a serious public health concern. The development of novel treatment strategies is therefore required. The interaction of nanostructures with microorganisms is fast-revolutionizing the biomedical field by offering advantages in both diagnostic and therapeutic applications. Nanoparticles offer unique physical properties that have associated benefits for drug delivery. These are predominantly due to the particle size (which affects bioavailability and circulation time), large surface area to volume ratio (enhanced solubility compared to larger particles), tunable surface charge of the particle with the possibility of encapsulation, and large drug payloads that can be accommodated. These properties, which are unlike bulk materials of the same compositions, make nanoparticulate drug delivery systems ideal candidates to explore in order to achieve and/or improve therapeutic effects. This review presents a broad overview of the application of nanosized materials for the treatment of common viral infections.

miRNA-30 family inhibition protects against cardiac ischemic injury by regulating cystathionine-γ-lyase expression

AIMS

Myocardial infarction (MI) is a leading cause of death globally. MicroRNAs (miRNAs) have been identified as a novel class of MI injury regulators. Hydrogen sulfide (H2S) is a gaseous signaling molecule that regulates cardiovascular function. The purpose of this study was to explore the role of the miR-30 family in protecting against MI injury by regulating H2S production.

RESULTS

The expression of miR-30 family was upregulated in the murine MI model as well as in the primary cardiomyocyte hypoxic model. However, the cystathionine-γ-lyase (CSE) expression was significantly decreased. The overexpression of miR-30 family decreased CSE expression, reduced H2S production, and then aggravated hypoxic cardiomyocyte injury. In contrast, silencing the whole miR-30 family can protect against hypoxic cell injury by elevating CSE and H2S level. Nonetheless, the protective effect was abolished by cotransfecting with CSE-siRNA. Systemic delivery of a locked nucleic acid (LNA)-miR-30 family inhibitor correspondingly increased CSE and H2S level, then reduced infarct size, decreased apoptotic cell number in the peri-infarct region, and improved cardiac function in response to MI. However, these cardioprotective effects were absent in CSE knockout mice. MiR-30b overexpression in vivo aggravated MI injury because of H2S reduction, and this could be rescued by S-propargyl-cysteine (SPRC), which is a novel modulator of CSE, or further exacerbated by propargylglycine (PAG), which is a selective inhibitor of CSE.

INNOVATION AND CONCLUSION

Our findings reveal a novel molecular mechanism for endogenous H2S production in the heart at the miRNA level and demonstrate the therapeutic potential of miR-30 family inhibition for ischemic heart diseases by increasing H2S production.

Target-responsive DNA/RNA nanomaterials for microRNA sensing and inhibition: the jack-of-all-trades in cancer nanotheranostics?

microRNAs (miRNAs) show high potential for cancer treatment, however one of the most significant bottlenecks in enabling miRNA effect is the need for an efficient vehicle capable of selective targeting to tumor cells without disrupting normal cells. Even more challenging is the ability to detect and silence multiple targets simultaneously with high sensitivity while precluding resistance to the therapeutic agents. Focusing on the pervasive role of miRNAs, herein we review the multiple nanomaterial-based systems that encapsulate DNA/RNA for miRNA sensing and inhibition in cancer therapy. Understanding the potential of miRNA detection and silencing while overcoming existing limitations will be critical to the optimization and clinical utilization of this technology.

Small RNA- and DNA-based gene therapy for the treatment of liver cirrhosis, where we are?

Chronic liver diseases with different aetiologies rely on the chronic activation of liver injuries which result in a fibrogenesis progression to the end stage of cirrhosis and liver failure. Based on the underlying cellular and molecular mechanisms of a liver fibrosis, there has been proposed several kinds of approaches for the treatment of liver fibrosis. Recently, liver gene therapy has been developed as an alternative way to liver transplantation, which is the only effective therapy for chronic liver diseases. The activation of hepatic stellate cells, a subsequent release of inflammatory cytokines and an accumulation of extracellular matrix during the liver fibrogenesis are the major obstacles to the treatment of liver fibrosis. Several targeted strategies have been developed, such as antisense oligodeoxynucleotides, RNA interference and decoy oligodeoxynucleotides to overcome this barriers. With this report an overview will be provided of targeted strategies for the treatment of liver cirrhosis, and particularly, of the targeted gene therapy using short RNA and DNA segments.

Stimuli-responsive polymeric nanoparticles for nanomedicine

Nature continues to be the ultimate in nanotechnology, where polymeric nanometer-scale architectures play a central role in biological systems. Inspired by the way nature forms functional supramolecular assemblies, researchers are trying to make nanostructures and to incorporate these into macrostructures as nature does. Recent advances and progress in nanoscience have demonstrated the great potential that nanomaterials have for applications in healthcare. In the realm of drug delivery, nanomaterials have been used in vivo to protect the drug entity in the systemic circulation, ensuring reproducible absorption of bioactive molecules that do not naturally penetrate biological barriers, restricting drug access to specific target sites. Several building blocks have been used in the formulation of nanoparticles. Thus, stability, drug release, and targeting can be tailored by surface modification. Herein the state of the art of stimuli-responsive polymeric nanoparticles are reviewed. Such systems are able to control drug release by reacting to naturally occurring or external applied stimuli. Special attention is paid to the design and nanoparticle formulation of these so-called smart drug-delivery systems. Future strategies for further developments of a promising controlled drug delivery responsive system are also outlined.

Use of RNA in drug design

This is a review of RNA as a target for small molecules (ribosomes, riboswitches, regulatory RNAs) and RNA-derived oligonucleotides as tools (antisense/small interfering RNA, ribozymes, aptamers/decoy RNA and microRNA). This review highlights the present state of research using RNA as a drug target or as a potential drug candidate and explains at which stage and to what extent rational design could eventually be involved. Special attention has been paid to the recent potential clinical applications of RNA either as drugs or drug targets. The review deals mainly with mechanistic approaches rather than with physicochemical or computational aspects of RNA-based drug design.

Anti-HIV-1 nanotherapeutics: promises and challenges for the future

The advent of highly active antiretroviral therapy (HAART) has significantly improved the prognosis for human immunodeficiency virus (HIV)-infected patients, however the adverse side effects associated with prolonged HAART therapy use continue. Although systemic viral load can be undetectable, the virus remains sequestered in anatomically privileged sites within the body. Nanotechnology-based delivery systems are being developed to target the virus within different tissue compartments and are being evaluated for their safety and efficacy. The current review outlines the various nanomaterials that are becoming increasingly used in biomedical applications by virtue of their robustness, safety, multimodality, and multifunctionality. Nanotechnology can revolutionize the field of HIV medicine by not only improving diagnosis, but also by improving delivery of antiretrovirals to targeted regions in the body and by significantly enhancing the efficacy of the currently available antiretroviral medications.

Delivery of chemo-sensitizing siRNAs to HER2+-breast cancer cells using RNA aptamers

Human epidermal growth factor receptor 2 (HER2) expression in breast cancer is associated with an aggressive phenotype and poor prognosis, making it an appealing therapeutic target. Trastuzumab, an HER2 antibody-based inhibitor, is currently the leading targeted treatment for HER2(+)-breast cancers. Unfortunately, many patients inevitably develop resistance to the therapy, highlighting the need for alternative targeted therapeutic options. In this study, we used a novel, cell-based selection approach for isolating 'cell-type specific', 'cell-internalizing RNA ligands (aptamers)' capable of delivering therapeutic small interfering RNAs (siRNAs) to HER2-expressing breast cancer cells. RNA aptamers with the greatest specificity and internalization potential were covalently linked to siRNAs targeting the anti-apoptotic gene, Bcl-2. We demonstrate that, when applied to cells, the HER2 aptamer-Bcl-2 siRNA conjugates selectively internalize into HER2(+)-cells and silence Bcl-2 gene expression. Importantly, Bcl-2 silencing sensitizes these cells to chemotherapy (cisplatin) suggesting a potential new therapeutic approach for treating breast cancers with HER2(+)-status. In summary, we describe a novel cell-based selection methodology that enables the identification of cell-internalizing RNA aptamers for targeting therapeutic siRNAs to HER2-expressing breast cancer cells. The future refinement of this technology may promote the widespread use of RNA-based reagents for targeted therapeutic applications.

Nanoscale Particles for Lung Delivery of siRNA

Small interfering RNAs (siRNAs) are potent molecules capable of blocking gene expression after entering cell cytoplasm. Despite their strong efficacy, they need to be carried by nanoscale delivery systems that can protect them against degradation in biological fluids, increase their cellular uptake and favor their subcellular distribution. Several studies have highlighted the potential of local pulmonary delivery of siRNAs for the treatment of lung diseases. For this purpose, nanoscale delivery systems were addressed to target passively or actively the target cell. This review discusses the possibilities of approaching lung delivery of nanoscale particles carrying siRNAs.

Nanomedicine for cancer: lipid-based nanostructures for drug delivery and monitoring

Recent advances in nanotechnology, materials science, and biotechnology have led to innovations in the field of nanomedicine. Improvements in the diagnosis and treatment of cancer are urgently needed, and it may now be possible to achieve marked improvements in both of these areas using nanomedicine. Lipid-coated nanoparticles containing diagnostic or therapeutic agents have been developed and studied for biomedical applications and provide a nanomedicine strategy with great potential. Lipid nanoparticles have cationic headgroups on their surfaces that bind anionic nucleic acids and contain hydrophobic drugs at the lipid membrane and hydrophilic drugs inside the hollow space in the interior. Moreover, researchers can design nanoparticles to work in combination with external stimuli such as magnetic field, light, and ionizing radiation, which adds further utility in biomedical applications. In this Account, we review several examples of lipid-based nanoparticles and describe their potential for cancer treatment and diagnosis. (1) The development of a lipid-based nanoparticle that included a promoter-enhancer and transcriptional activator greatly improved gene therapy. (2) The addition of a radiosensitive promoter to lipid nanoparticles was sufficient to confer radioisotope-activated expression of the genes delivered by the nanoparticles. (3) We successfully tailored lipid nanoparticle composition to increase gene transduction in scirrhous gastric cancer cells. (4) When lipophilic photosensitizing molecules were incorporated into lipid nanoparticles, those particles showed an increased photodynamic cytotoxic effect on the target cancer. (5) Coating an Fe(3)O(4) nanocrystal with lipids proved to be an efficient strategy for magnetically guided gene-silencing in tumor tissues. (6) An Fe(16)N(2)/lipid nanocomposite displayed effective magnetism and gene delivery in cancer cells. (7) Lipid-coated magnetic hollow capsules carried aqueous anticancer drugs and delivered them in response to a magnetic field. (8) Fluorescent lipid-coated and antibody-conjugated magnetic nanoparticles detected cancer-associated antigen in a microfluidic channel. We believe that the continuing development of lipid-based nanomedicine will lead to the sensitive minimally invasive treatment of cancer. Moreover, the fusion of different scientific fields is accelerating these developments, and we expect these interdisciplinary efforts to have considerable ripple effects on various fields of research.

Noble metal nanoparticles applications in cancer

Nanotechnology has prompted new and improved materials for biomedical applications with particular emphasis in therapy and diagnostics. Special interest has been directed at providing enhanced molecular therapeutics for cancer, where conventional approaches do not effectively differentiate between cancerous and normal cells; that is, they lack specificity. This normally causes systemic toxicity and severe and adverse side effects with concomitant loss of quality of life. Because of their small size, nanoparticles can readily interact with biomolecules both at surface and inside cells, yielding better signals and target specificity for diagnostics and therapeutics. This way, a variety of nanoparticles with the possibility of diversified modification with biomolecules have been investigated for biomedical applications including their use in highly sensitive imaging assays, thermal ablation, and radiotherapy enhancement as well as drug and gene delivery and silencing. Here, we review the available noble metal nanoparticles for cancer therapy, with particular focus on those already being translated into clinical settings.

A double-modulation strategy in cancer treatment with a chemotherapeutic agent and siRNA

5-Fluorouracil (5-FU) is broadly considered the drug of choice for treating human colorectal cancer (CRC). However, 5-FU resistance, mainly caused by the overexpression of antiapoptotic proteins such as Bcl-2, often leads ultimately to treatment failure. We here investigated the effect of Bcl-2 gene silencing, using small interfering RNA (siRNA) (siBcl-2), on the efficacy of 5-FU in CRC. Transfection of siBcl-2 by a Lipofectamine2000/siRNA lipoplex effectively downregulated Bcl-2 expression in the DLD-1 cell line (a CRC), resulting in significant cell growth inhibition in vitro upon treatment with 5-FU. For in vivo treatments, S-1, an oral formulation of Tegafur (TF), a prodrug of 5-FU, was used to mimic 5-FU infusion. The combined treatment of polyethylene glycol (PEG)-coated siBcl-2-lipoplex and S-1 showed superior tumor growth suppression in a DLD-1 xenograft model, compared to each single treatment. Surprisingly, daily S-1 treatment enhanced the accumulation of PEG-coated siBcl-2-lipoplex in tumor tissue. We propose a novel double modulation strategy in cancer treatment, in which chemotherapy enhances intratumoral siRNA delivery and the delivered siRNA enhances the chemosensitivity of tumors. Combination of siRNA-containing nanocarriers with chemotherapy may compensate for the limited delivery of siRNA to tumor tissue. In addition, such modulation strategy may be considered a promising therapeutic approach to successfully managing 5-FU-resistant tumors.

Alternative for anti-TNF antibodies for arthritis treatment

Tumor necrosis factor-α (TNF-α), a proinflammatory cytokine, plays a key role in the pathogenesis of many inflammatory diseases, including arthritis. Neutralization of this cytokine by anti-TNF-α antibodies has shown its efficacy in rheumatoid arthritis (RA) and is now widely used. Nevertheless, some patients currently treated with anti-TNF-α remain refractory or become nonresponder to these treatments. In this context, there is a need for new or complementary therapeutic strategies. In this study, we investigated in vitro and in vivo anti-inflammatory potentialities of an anti-TNF-α triplex-forming oligonucleotide (TFO), as judged from effects on two rat arthritis models. The inhibitory activity of this TFO on articular cells (synoviocytes and chondrocytes) was verified and compared to that of small interfering RNA (siRNA) in vitro. The use of the anti-TNF-α TFO as a preventive and local treatment in both acute and chronic arthritis models significantly reduced disease development. Furthermore, the TFO efficiently blocked synovitis and cartilage and bone destruction in the joints. The results presented here provide the first evidence that gene targeting by anti-TNF-α TFO modulates arthritis in vivo, thus providing proof-of-concept that it could be used as therapeutic tool for TNF-α-dependent inflammatory disorders.

In vitro release characteristics and cellular uptake of poly(D,L-lactic-co-glycolic acid) nanoparticles for topical delivery of antisense oligodeoxynucleotides

The efficacy of antisense oligodeoxynucleotides (AsODNs) is compromised by their poor stability in biological fluids and the inefficient cellular uptake due to their size and negative charge. Since chemical modifications of these molecules have resulted in a number of non-antisense activities, incorporation into particulate delivery systems has offered a promising alternative. The aim of this study was to evaluate various poly(D,L-lactic-co-glycolic acid) (PLGA) nanoparticles for AsODN entrapment and delivery. PLGA nanoparticles were prepared using the double emulsion solvent evaporation method. The influence of formulation parameters such as PLGA concentration and volume ratio of internal aqueous phase volume (Va1) to organic phase volume (Vo) to external aqueous phase volume (Va2) on particle size, polydispersity index (PDI) and zeta potential (ZP) was investigated using a full factorial study. The particle size increased with increasing PLGA concentrations and volume ratios, with an interaction detectable between the two factors. AsODN entrapment efficiencies ranged between 49.97% and 54.95% with no significant difference between various formulations. By fitting the in vitro release profiles to a dual first order release model it was shown that the AsODN release occurred via two processes: a diffusion controlled process in the early phase (25 to 32% within one day) and a PLGA degradation process in the latter (39 to 70% after 14 days). Cellular uptake studies using primary corneal epithelial cells suggested active transport of nanoparticles via endocytosis. PLGA nanoparticles therefore show potential to successfully entrap AsODNs, transport them into cells and release them over time due to polymer erosion.

In vitro transcription and translation inhibition via DNA functionalized gold nanoparticles

The use of gold nanoparticles (AuNPs) has been gaining momentum as vectors for gene silencing strategies, combining the AuNPs' ease of functionalization with DNA and/or siRNA, high loading capacity and fast uptake by target cells. Here, we used AuNP functionalized with thiolated oligonucleotides to specifically inhibit transcription in vitro, demonstrating the synergetic effect between AuNPs and a specific antisense sequence that blocks the T7 promoter region. Also, AuNPs efficiently protect the antisense oligonucleotide against nuclease degradation, which can thus retain its inhibitory potential. In addition, we demonstrate that AuNPs functionalized with a thiolated oligonucleotide complementary to the ribosome binding site and the start codon, effectively shut down in vitro translation. Together, these two approaches can provide for a simple yet robust experimental set up to test for efficient gene silencing of AuNP-DNA conjugates. What is more, these results show that appropriate functionalization of AuNPs can be used as a dual targeting approach to an enhanced control of gene expression-inhibition of both transcription and translation.

Cationic shell-cross-linked knedel-like (cSCK) nanoparticles for highly efficient PNA delivery

Peptide nucleic acids have a number of features that make them an ideal platform for the development of in vitro biological probes and tools. Unfortunately, their inability to pass through membranes has limited their in vivo application as diagnostic and therapeutic agents. Herein, we describe the development of cationic shell-cross-linked knedel-like (cSCK) nanoparticles as highly efficient vehicles for the delivery of PNAs into cells, either through electrostatic complexation with a PNA * ODN hybrid, or through a bioreductively cleavable disulfide linkage to a PNA. These delivery systems are better than the standard Lipofectamine/ODN-mediated method and much better than the Arg(g)-mediated method for PNA delivery in HeLa cells, showing lower toxicity and higher bioactivity. The cSCKs were also found to facilitate both endocytosis and endosomal release of the PNAs, while themselves remaining trapped in the endosomes.

Controlled delivery of antisense oligonucleotides: a brief review of current strategies

Antisense therapy has been investigated extensively over the past two decades, either experimentally for gene functional research or clinically as therapeutic agents owing to the conceptual simplicity, ease of design and low cost. The concept of this therapeutic approach is promising because short antisense oligonucleotides (ASOs) can be delivered into target cells for specific hybridisation with target mRNA, resulting in the inhibition of the expression of pathogenic genes. However, the efficient delivery of the ASO molecules into target cells remains challenging; this bottleneck together with several other technical hurdles need to be overcome before this approach becomes effective and widely adopted. A variety of vectors such as lipids, polymers, peptides and nanoparticles have been explored. This review outlines the recent advances of the non-viral ASO delivery strategies. Several recent scientific studies, including authors' contributions, have been selected to highlight the technical aspects of ASO delivery.

A novel magnetic crystal-lipid nanostructure for magnetically guided in vivo gene delivery

Cancer gene therapy requires a safe and effective gene delivery system. Polymer- and lipid-coated magnetic nanocrystals have been used to deliver silencing RNA, but synthesizing these magnetic vectors is difficult. Here, we show that a new nanoparticle formulation can be magnetically guided to deliver and silence genes in cells and tumours in mice. This formulation, termed LipoMag, consists of an oleic acid-coated magnetic nanocrystal core and a cationic lipid shell. When compared with the commercially available PolyMag formulation, LipoMag displayed more efficient gene silencing in 9 of 13 cell lines, and better anti-tumour effects when systemically administered to mice bearing gastric tumours. By delivering an optimized sequence of a silencing RNA that targets the epidermal growth factor receptor of tumour vessels, the intended therapeutic benefit was achieved with no evident adverse immune reaction or untoward side effects.

Nanotechnology for parasitic plant control

The field of nanotechnology opens up novel potential applications for agriculture. Nanotechnology applications are already being explored and used in medicine and pharmacology, but interest for use in crop protection is just starting. The development of nanodevices as smart delivery systems to target specific sites and nanocarriers for controlled chemical release is discussed. Some nanotechnologies can improve existing crop management techniques in the short to medium term. Nanocapsules would help to avoid phytotoxicity on the crop by using systemic herbicides against parasitic weeds. Nanoencapsulation can also improve herbicide application, providing better penetration through cuticles and tissues, and allowing slow and constant release of the active substances. On the other hand, new crop management tools could be developed on the basis of medical applications. Nanoparticles have a great potential as 'magic bullets', loaded with herbicides, chemicals or nucleic acids, and targeting specific plant tissues or areas to release their charge. Viral capsids can be altered by mutagenesis to achieve different configurations and deliver specific nucleic acids, enzymes or antimicrobial peptides acting against the parasites. Many issues are still to be addressed, such as increasing the scale of production processes and lowering costs, as well as toxicological issues, but the foundations of a new plant treatment concept have been laid, and applications in the field of parasitic plant control can be started.

Molecular imaging study on in vivo distribution and pharmacokinetics of modified small interfering RNAs (siRNAs)

Molecular imaging was used to study the biodistribution, pharmacokinetics, and activity of naked small interfering RNAs (siRNAs). siRNAs with riboses chemically modified in the 2' position were compared with unmodified siRNA. In vitro, replacement of the 2'-hydroxyl (2'OH) group of certain nucleotides in an siRNA sequence by a fluorine atom (2'F) on both antisense (AS) and sense (S) strands [2'F(AS/S)], or by a methoxy group (2'OMe) on the S strand [2'OH(AS)/2'OMe(S)], was compatible with RNA interference. Different siRNAs [2'F(AS/S), 2'OH(AS)/2'OMe(S), and 2'OH(AS/S)] were labeled with fluorine-18 (conjugation with [(18)F]FPyBrA), and comparative dynamic and quantitative imaging was performed with positron emission tomography. After intravenous injections of [(18)F]siRNAs in rodents, total radioactivity was rapidly eliminated by the kidneys and the liver. Tissue distribution of the different siRNAs were similar, and their bioavailability (as judged from blood persistence and stability) increased in the order 2'OH(AS/S) = 2'OH(AS)/2'OMe(S) < 2'F(AS/S). However, in our in vivo model, the 2'F(AS/S) siRNA, despite its higher bioavailability, was not able to induce a higher interference effect with respect to the 2'OH(AS/S) siRNA. Molecular imaging approaches, applied in the present work to both natural and chemically modified siRNAs, can contribute to the development of these macromolecules as therapeutic agents.

Methods for the preparation and manufacture of polymeric nanoparticles

This review summarizes the different methods of preparation of polymer nanoparticles including nanospheres and nanocapsules. The first part summarizes the basic principle of each method of nanoparticle preparation. It presents the most recent innovations and progresses obtained over the last decade and which were not included in previous reviews on the subject. Strategies for the obtaining of nanoparticles with controlled in vivo fate are described in the second part of the review. A paragraph summarizing scaling up of nanoparticle production and presenting corresponding pilot set-up is considered in the third part of the review. Treatments of nanoparticles, applied after the synthesis, are described in the next part including purification, sterilization, lyophilization and concentration. Finally, methods to obtain labelled nanoparticles for in vitro and in vivo investigations are described in the last part of this review.

Polymer nanocarriers for the delivery of small fragments of nucleic acids: oligonucleotides and siRNA

The success of the application of new therapeutic methods based on RNA interfering strategies requires the in vivo delivery of active ODN or siRNA down to the intracellular compartment of the target cells. This article aims to review the studies related to the formulation of RNA interfering agents in polymer nanocarriers. It will present the different types of polymer nanocarriers used as well as the biological activity of the resulting ODN and siRNA loaded nanocarriers. As will be explained, the part of the in vitro studies provided useful data about the intracellular delivery of the formulated RNA interfering agents. Investigations performed in vivo have considered animal models of different relevant diseases. Results from these investigations have clearly demonstrated the interest of several polymer nanocarriers tested so far to deliver active RNA interfering effectors in vivo making possible their administration by the intravenous route.

Effect of trastuzumab-modified antisense oligonucleotide-loaded human serum albumin nanoparticles prepared by heat denaturation

Nanoparticles represent a promising tool for targeted drug delivery to tumour cells and are able to protect drugs against degradation. In our present study we developed targeted nanoparticles loaded with antisense oligonucleotides (ASOs) against Plk1 (polo-like kinase 1) prepared by heat denaturation instead of using glutaraldehyde. Glutaraldehyde can lead to an inactivation of ASOs through chemical crosslinking and is a toxic entity. We examined the ideal preparation conditions and characterised the resulting particles in terms of physico-chemical properties, ASO recovery after enzymatic degradation and stability. Stable monodisperse nanoparticles with an ASO recovery of more than 80% could be prepared at a temperature of 105 degrees C for 10 min. Furthermore we performed quantitative real-time PCR and Western blot to detect an ASO-mediated effect on Plk1 in BT-474 cells. We observed a significant reduction of Plk1 mRNA and protein expression. Thus, this is the first report of ASO-loaded HSA nanoparticles prepared by heat denaturation, where an impact on gene expression could be observed. The data provide the basis for the further development of carrier systems for ASOs to reduce off-target effects evoked by systemically administered ASOs and to achieve a better penetration into primary and metastatic target cells.

Development of an antisense RNA delivery system using conjugates of the MS2 bacteriophage capsids and HIV-1 TAT cell-penetrating peptide

RNA-based therapeutic strategies are used widely due to their highly specific mode of action. However, the major obstacle in any RNA-based therapy is cellular delivery and stability in the cells. The self-assembly of the MS2 bacteriophage capsids has been used to develop virus-like particles (VLPs) for drug delivery. In this study, we utilized the heterobifunctional crosslinker, sulfosuccinimidyl-4-(p-maleimidophenyl)-butyrate (sulfo-SMPB), to conjugate the human immunodeficiency virus-1 (HIV-1) Tat peptide and MS2 VLPs; the antisense RNA against the 5'-untranslated region (UTR) and the internal ribosome entry site (IRES) of the hepatitis C virus (HCV) was packaged into these particles by using a two-plasmid coexpression system. The MS2 VLPs conjugated with the Tat peptide were then transferred into Huh-7 cells containing an HCV reporter system. The packaged antisense RNA showed an inhibitory effect on the translation of HCV. This paper describes our initial results with this system using the Tat peptide.

Micro/nanostructured polymeric systems for biomedical and pharmaceutical applications

This review provides an outline of the polymeric micro/nanostructured advanced systems that are suited for the controlled and targeted administration of, specifically, nonconventional drugs. The contribution of new trends in drug-delivery technology is focused on two major parts, dealing with brief surveys of: the biodegradable/bioerodible polymeric systems used in the formulation of micro/nanoparticles and techniques used in the preparation of micro/nanoparticles for their biomedical application in cancer treatment specifically, in inflammation pathologies, as oxygen carriers (blood substitutes) and in tissue-engineering practice. A small discussion of the future perspectives of the described systems is also given.

Polynucleotide kinase as a potential target for enhancing cytotoxicity by ionizing radiation and topoisomerase I inhibitors

The cytotoxicity of many antineoplastic agents is due to their capacity to damage DNA and there is evidence indicating that DNA repair contributes to the cellular resistance to such agents. DNA strand breaks constitute a significant proportion of the lesions generated by a broad range of genotoxic agents, either directly, or during the course of DNA repair. Strand breaks that are caused by many agents including ionizing radiation, topoisomerase I inhibitors, and DNA repair glycosylases such as NEIL1 and NEIL2, often contain 5'-hydroxyl and/or 3'-phosphate termini. These ends must be converted to 5'-phosphate and 3'-hydroxyl termini in order to allow DNA polymerases and ligases to catalyze repair synthesis and strand rejoining. A key enzyme involved in this end-processing is polynucleotide kinase (PNK), which possesses two enzyme activities, a DNA 5'-kinase activity and a 3'-phosphatase activity. PNK participates in the single-strand break repair pathway and the non-homologous end joining pathway for double-strand break repair. RNAi-mediated down-regulation of PNK renders cells more sensitive to ionizing radiation and camptothecin, a topoisomerase I inhibitor. Structural analysis of PNK revealed the protein is composed of three domains, the kinase domain at the C-terminus, the phosphatase domain in the centre and a forkhead associated (FHA) domain at the N-terminus. The FHA domain plays a critical role in the binding of PNK to other DNA repair proteins. Thus each PNK domain may be a suitable target for small molecule inhibition to effectively reduce resistance to ionizing radiation and topoisomerase I inhibitors.

Design aspects of poly(alkylcyanoacrylate) nanoparticles for drug delivery

Poly(alkylcyanoacrylate) (PACA) nanoparticles were first developed 25 years ago taking advantage of the in vivo degradation potential of the polymer and of its good acceptance by living tissues. Since then, various PACA nanoparticles were designed including nanospheres, oil-containing and water-containing nanocapsules. This made possible the in vivo delivery of many types of drugs including those presenting serious challenging delivery problems. PACA nanoparticles were proven to improve treatments of severe diseases like cancer, infections and metabolic disease. For instance, they can transport drugs across barriers allowing delivery of therapeutic doses in difficult tissues to reach including in the brain or in multidrug resistant cells. This review gives an update on the more recent developments and achievements on design aspects of PACA nanoparticles as delivery systems for various drugs to be administered in vivo by different routes of administration.

siRNA nanoformulation against the ret/PTC1 junction oncogene is efficient in an in vivo model of papillary thyroid carcinoma

Delivery is a very important concern for therapeutic applications of siRNA. In this study, we have used chitosan-coated poly(isobutylcyanoacrylate) nanoparticles to deliver siRNA with a complementary sequence to the fusion oncogene ret/PTC1. By screening the mRNA junction we have selected a potent siRNA sequence able to inhibit this oncogene in a model of Papillary Thyroid Carcinoma cells. This siRNA sequence has then been validated by a shRNA approach using the same sequence. Furthermore, the high ret/PTC1 inhibition has triggered a phenotypic reversion of the transformed cells. We have designed well-defined chitosan decorated nanoparticles and succeeded to reduce their size. They have allowed to protect ret/PTC1 siRNA from in vivo degradation and leading to significant tumour growth inhibition after intratumoral administration.