Conjugation of prostate cancer-specific aptamers to polyethylene glycol-grafted polyethylenimine for enhanced gene delivery to prostate cancer cells

Tumor Microenvironment-Responsive Polymer-Based RNA Delivery Systems for Cancer Treatment

Ribonucleic acid (RNA) therapeutics offer a broad prospect in cancer treatment. However, their successful application requires overcoming various physiological barriers to effectively deliver RNAs to the target sites. Currently, a number of RNA delivery systems based on polymeric nanoparticles are developed to overcome these barriers in RNA delivery. This work provides an overview of the existing RNA therapeutics for cancer gene therapy, and particularly summarizes those that are entering the clinical phase. This work then discusses the core features and latest research developments of tumor microenvironment-responsive polymer-based RNA delivery carriers which are designed based on the pathological characteristics of the tumor microenvironment. Finally, this work also proposes opportunities for the transformation of RNA therapies into cancer immunotherapy methods in clinical applications.

Optimal delivery strategies for nanoparticle-mediated mRNA delivery

Messenger RNA (mRNA) has emerged as a new and efficient agent for the treatment of various diseases. The success of lipid nanoparticle-mRNA against the novel coronavirus (SARS-CoV-2) pneumonia epidemic has proved the clinical potential of nanoparticle-mRNA formulations. However, the deficiency in the effective biological distribution, high transfection efficiency and good biosafety are still the major challenges in clinical translation of nanomedicine for mRNA delivery. To date, a variety of promising nanoparticles have been constructed and then gradually optimized to facilitate the effective biodistribution of carriers and efficient mRNA delivery. In this review, we describe the design of nanoparticles with an emphasis on lipid nanoparticles, and discuss the manipulation strategies for nanoparticle-biology (nano-bio) interactions for mRNA delivery to overcome the biological barriers and improve the delivery efficiency, because the specific nano-bio interaction of nanoparticles usually remoulds the biomedical and physiological properties of the nanoparticles especially the biodistribution, mechanism of cellular internalization and immune response. Finally, we give a perspective for the future applications of this promising technology. We believe that the regulation of nano-bio interactions would be a significant breakthrough to improve the mRNA delivery efficiency and cross biological barriers. This review may provide a new direction for the design of nanoparticle-mediated mRNA delivery systems.

Investigating Efficacy of Three DNA-Aptamers in Targeted Plasmid Delivery to Human Prostate Cancer Cell Lines

Selection of targeted and efficient carriers to deliver drugs and genes to cells and tissues is still a major challenge and to overcome this obstacle, aptamers conjugated to nanoparticles have been broadly examined. To assess whether polycation of aptamers can improve plasmid delivery efficacy, we investigated the effect of three DNA-aptamers (AS1411, WY-5a, and Sgs-8) conjugated to branched polyethylenimine (b-PEI; MW ∼25 kDa) with different combinations of gene (plasmid) for delivery to prostate cancer cell lines (DU145 and PC3). According to transfection assessments, the dual conjugation of aptamers (AS:WY) with b-PEI produced the best results and increased the efficiency of plasmid delivery to up to three folds compared to unmodified PEI. Surprisingly, triple aptamer arrangement not only reduced transfection ability but also showed cytotoxicity. While our results demonstrated potential synergistic effects of AS1411 and WY-5a aptamers for gene delivery, it is important to note that the present evidence relies on the aptamer and cell types.

Advances in aptamer-based drug delivery vehicles for cancer therapy

Overall, aptamers are special classes of nucleic acid-based macromolecules that are beginning to investigate because of their capability of avidity binding to a specific target for clinical use. Taking advantage of target-specific medicine led to more effective therapeutic and limitation of side effects of drugs. Herein, we discuss several aptamers and their binding capability and capacity for selecting tumor biomarkers and usage of them as targeting ligands for the functionalization of nanomaterials. We review recent applications based on aptamers and several nanoparticles to rise efficacy and develop carrier systems such as graphene oxide, folic acid, gold, mesopores silica, and various polymers and copolymer, polyethylene glycol, cyclodextrin, chitosan. The nanocarriers have been characterized by particle size, zeta potential, aptamer conjugation, and drug encapsulation efficiency. Hydrodynamic diameter and Zeta potential can used in order to monitor aptamers' crosslinking, in-vitro drug release, intracellular delivery of nanocarriers, and cellular cytotoxicity assay. Also, they are studied for cellular uptake and internalization to types of cancer cell lines such as colorectal, breast, prostate, leukemia and etc. The results are investigated in in-vivo cytotoxicity assay and cell viability assay. Targeted cancer therapy seems a good and promising strategy to overcome the systemic toxicity of chemotherapy.

Progress in cancer drug delivery based on AS1411 oriented nanomaterials

Targeted cancer therapy has become one of the most important medical methods because of the spreading and metastatic nature of cancer. Based on the introduction of AS1411 and its four-chain structure, this paper reviews the research progress in cancer detection and drug delivery systems by modifying AS1411 aptamers based on graphene, mesoporous silica, silver and gold. The application of AS1411 in cancer treatment and drug delivery and the use of AS1411 as a targeting agent for the detection of cancer markers such as nucleoli were summarized from three aspects of active targeting, passive targeting and targeted nucleic acid apharmers. Although AS1411 has been withdrawn from clinical trials, the research surrounding its structural optimization is still very popular. Further progress has been made in the modification of nanoparticles loaded with TCM extracts by AS1411.

Targeted delivery of miR-218 via decorated hyperbranched polyamidoamine for liver cancer regression

Hepatocellular carcinoma (HCC) is one of most common causes of cancer death worldwide. MicroRNA (miRNA) replacement gene therapy is a novel approach for HCC management. MiR-218 is a promising tumor suppressor miRNA that is down-regulated in HCC. Here, our aim was the targeted delivery of miR-218 expressing DNA plasmid (pmiR-218) to suppress HCC in vitro and in vivo. Hyperbranched polyamidoamine was synthesized via simple and economically one-pot reaction followed by decoration with lactobionic acid (LA-PAMAM) to selectively deliver and restore miR-218 expression in HCC. In vitro cytotoxicity investigations revealed the high biocompatibility of LA-PAMAM. Furthermore, decoration of hyperbranched polymer with LA moieties enabled LA-PAMAM to deliver pmiR-218 more efficiently to HepG2 cells compared to both PMAMA and naked pmiR-218. Such efficient delivery of miR-218 resulted in suppression of HepG2 proliferation and down-regulation of its oncogenic HOXA1 target. In vivo, LA-PAMAM/pmiR-218 treatment of HCC induced by DEN and CCl₄ in mice leads to an obvious decrease in the number and size of HCC nodules. In addition, LA-PAMAM/pmiR-218 significantly improved the liver histological features, as well as down-regulated the HOXA1 in liver tissue. In conclusion, this study showed the potential of LA-PAMAM carrier for the targeted delivery of tumor suppressor miR-218 as a therapeutic candidate for HCC.

A review of the tortuous path of nonviral gene delivery and recent progress

Gene therapy encompasses the transfer of exogenous genetic materials into the patient's target cells to treat or prevent diseases. Nevertheless, the transfer of genetic material into desired cells is challenging and often requires specialized tools or delivery systems. For the past 40 years, scientists are mainly pursuing various viruses as gene delivery vectors, and the overall progress has been slow and far from the expectation. As an alternative, nonviral vectors have gained substantial attention due to their several advantages, including superior safety profile, enhanced payload capacity, and stealth abilities. Since nonviral vectors encounter multiple extra- and intra-cellular barriers limiting the transfer of genetic payload into the target cell nucleus, we have discussed these barriers in detail for this review. A direct approach, utilizing physical methods like electroporation, sonoporation, gene gun, eliminate the requirement for a specific carrier for gene delivery. In contrast, chemical methods of gene transfer exploit natural or synthetic compounds as carriers to increase cellular targeting and gene therapy effectiveness. We have also emphasized the recent advancements aimed at enhancing the current nonviral approaches. Therefore, in this review, we have focused on discussing the current evolving state of nonviral gene delivery systems and their future perspectives.

PH-Responsive, Cell-Penetrating, Core/Shell Magnetite/Silver Nanoparticles for the Delivery of Plasmids: Preparation, Characterization, and Preliminary In Vitro Evaluation

Over the past decade, gene therapies have attracted much attention for the development of treatments for various conditions, including cancer, neurodegenerative diseases, protein deficiencies, and autoimmune disorders. Despite the benefits of this approach, several challenges are yet to be solved to reach clinical implementation. Some of these challenges include low transfection rates, limited stability under physiological conditions, and low specificity towards the target cells. An avenue to overcome such issues is to deliver the therapies with the aid of potent cell-penetrating vectors. Non-viral vectors, such as nanostructured materials, have been successfully tested in drug and gene delivery. Here, we propose the development and in vitro evaluation of a nanostructured cell-penetrating vehicle based on core/shell, magnetite/silver nanoparticles. A subsequent conjugation of a pH-responsive polymer was used to assure that the vehicle can carry and release circular DNA. Additionally, the translocating peptide Buforin II was conjugated with the aid of a polyether amine polymer to facilitate translocation and endosome escape. The obtained nanobioconjugates (magnetite/silver-pDMAEMA-PEA-BUFII) were characterized by UV-Vis spectrophotometry, dynamic light scattering (DLS), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope equipped with energy dispersive spectroscopy (SEM+EDS), and transmission electron microscopy (TEM). They were also encapsulated in lecithin liposomes to form magnetoliposomes. The cell viability of Vero cells in the presence of the nanobioconjugates was above 95% and declined to 80% for the magnetoliposomes. The hemolytic tendency of nanobioconjugates and magnetoliposomes was below 10%, while the platelet aggregation approached that of the negative control (i.e., 35%). Cytoplasm coverage values of about 50% for both Vero and neuroblastoma cells confirmed significant cell penetration. Pearson's correlation coefficients for both cell lines allowed us to estimate 20-40% colocalization of the nanobioconjugates with lysotracker green, which implied high levels of endosomal escape. The developed vehicles were also capable of loading around 16% of the added DNA and releasing such cargo with 8% efficiency. The developed nanoplatform holds a significant promise to enable highly efficient gene therapies as it overcomes some of the major issues associated with their eventual translation to the pre-clinical and clinical scale.

Aptamer Hybrid Nanocomplexes as Targeting Components for Antibiotic/Gene Delivery Systems and Diagnostics: A Review

With the passage of time and more advanced societies, there is a greater emergence and incidence of disease and necessity for improved treatments. In this respect, nowadays, aptamers, with their better efficiency at diagnosing and treating diseases than antibodies, are at the center of attention. Here, in this review, we first investigate aptamer function in various fields (such as the detection and remedy of pathogens, modification of nanoparticles, antibiotic delivery and gene delivery). Then, we present aptamer-conjugated nanocomplexes as the main and efficient factor in gene delivery. Finally, we focus on the targeted co-delivery of genes and drugs by nanocomplexes, as a new exciting approach for cancer treatment in the decades ahead to meet our growing societal needs.