Synthetic delivery systems for intravenous administration of nucleic acids

Nucleic acid-based therapy for brain cancer: Challenges and strategies

Nucleic acid-based therapy emerges as a powerful weapon for the treatment of tumors thanks to its direct, effective, and lasting therapeutic effect. Encouragingly, continuous nucleic acid-based drugs have been approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA). Despite the tremendous progress, there are few nucleic acid-based drugs for brain tumors in clinic. The most challenging problems lie on the instability of nucleic acids, difficulty in traversing the biological barriers, and the off-target effect. Herein, nucleic acid-based therapy for brain tumor is summarized considering three aspects: (i) the therapeutic nucleic acids and their applications in clinical trials; (ii) the various administration routes for nucleic acid delivery and the respective advantages and drawbacks. (iii) the strategies and carriers for improving stability and targeting ability of nucleic acid drugs. This review provides thorough knowledge for the rational design of nucleic acid-based drugs against brain tumor.

Anisamide-targeted PEGylated gold nanoparticles designed to target prostate cancer mediate: Enhanced systemic exposure of siRNA, tumour growth suppression and a synergistic therapeutic response in combination with paclitaxel in mice

Small interfering RNA (siRNA) has recently illustrated therapeutic potential for malignant disorders. However, the clinical application of siRNA-based therapeutics is significantly retarded by the paucity of successful delivery systems. Recently, multifunctional gold nanoparticles (AuNPs) as non-viral delivery carriers have shown promise for transporting chemotherapeutics, proteins/peptides, and genes. In this study, AuNPs capped with polyethylenimine (PEI) and PEGylated anisamide (a ligand known to target the sigma receptor) have been developed to produce a range of positively charged anisamide-targeted PEGylated AuNPs (namely Au-PEI-PEG-AA). The anisamide-targeted AuNPs effectively complexed siRNA via electrostatic interaction, and the resultant complex (Au₁₁₀-PEI-PEG₅₀₀₀-AA.siRNA) illustrated favourable physicochemical characteristics, including particle size, surface charge, and stability. In vitro, anisamide-targeted AuNPs selectively bound to human prostate cancer PC-3 cells, inducing efficient endosomal escape of siRNA, and effective downregulation of the RelA gene. In vivo, prolonged systemic exposure of siRNA was achieved by anisamide-targeted AuNPs resulting in significant tumour growth suppression in a PC3 xenograft mouse model without an increase in toxicity. In addition, a combination of siRNA-mediated NF-κB knockdown using anisamide-targeted AuNPs with Paclitaxel produced a synergistic therapeutic response, thus providing a promising therapeutic strategy for the treatment of prostate cancer.

Non-viral nanosystems for gene and small interfering RNA delivery to the central nervous system: formulating the solution

The application of gene and RNAi-based therapies to the central nervous system (CNS), for neurological and neurodegenerative disease, offers immense potential. The issue of delivery to the target site remains the single greatest barrier to achieving this. There are challenges to gene and siRNA (small interfering RNA) delivery which are specific to the CNS, including the post-mitotic nature of neurons, their resistance to transfection and the blood-brain barrier. Viral vectors are highly efficient and have been used extensively in pre-clinical studies for CNS diseases. However, non-viral delivery offers an exciting alternative. In this review, we will discuss the extracellular and intracellular barriers to gene and siRNA delivery in the CNS. Our focus will be directed towards various non-viral strategies used to overcome these barriers. In this regard, we describe selected non-viral vectors and categorise them according to the barriers that they overcome by their formulation and targeting strategies. Some of the difficulties associated with non-viral vectors such as toxicity, large-scale manufacture and route of administration are discussed. We provide examples of optimised formulation approaches and discuss regulatory hurdles to clinical validation. Finally, we outline the components of an "ideal" formulation, based on a critical analysis of the approaches highlighted throughout the review.

Multifunctional imaging nanoprobes

Multifunctional imaging nanoprobes have proven to be of great value in the research of pathological processes, as well as the assessment of the delivery, fate, and therapeutic potential of encapsulated drugs. Moreover, such probes may potentially support therapy schemes by the exploitation of their own physical properties, e.g., through thermal ablation. This review will present four classes of nanoparticulate imaging probes used in this area: multifunctional probes (1) that can be tracked with at least three different and complementary imaging techniques, (2) that carry a drug and have bimodal imaging properties, (3) that are employed for nucleic acid delivery and imaging, and (4) imaging probes with capabilities that can be used for thermal ablation. We will highlight several examples where the suitable combination of different (bio)materials like polymers, inorganic nanocrystals, fluorophores, proteins/peptides, and lipids can be tailored to manufacture multifunctional probes to accomplish nanomaterials of each of the aforementioned classes. Moreover, it will be demonstrated how multimodality imaging approaches improve our understanding of in vivo nanoparticle behavior and efficacy at different levels, ranging from the subcellular level to the whole body.