Cell-based high-throughput screening of cationic polymers for efficient DNA and siRNA delivery

Module-combinatorial design and screening of multifunctional polymers based on polyaspartic acid for DNA delivery

It is crucial to develop non-viral gene vectors that can efficiently and safely transfect plasmid DNA into cells. Low transfection efficiency and high cytotoxicity of cationic polymers hinder their application as gene carriers. Modification of cationic polymers has emerged as an attractive strategy for efficient and safe nucleic acids delivery. In this study, a simple and rapid method is developed to synthesize a series of multifunctional polymers by utilizing biodegradable polyaspartic acid as the backbone and modifying it with three modules. This one-component polymer possesses capabilities for nucleic acid condensation, cellular uptake, and endosomal escape. Polymers containing imidazole, triazole, or pyridine group exhibited promising transfection activity. Substituted with dodecylamine or 2-hexyldecan-1-amine enhance cellular uptake and subsequent transfection. Furthermore, the influence of ionizable amine side chains on gene delivery is investigated. Two optimal polymers, combined with the avian encephalomyelitis virus (AEV) plasmid vaccine, induced robust specific antibody responses and cellular immune responses in mice and chickens. Through module-combination design and screening of polyaspartamide polymers, this study presents a paradigm for the development of gene delivery vectors.

Synthesis of Amino Acid-Based Cationic Lipids and Study of the Role of the Cationic Head Group for Enhanced Drug and Nucleic Acid Delivery

Leveraging liposomes for drug and nucleic acid delivery, though promising due to reduced toxicity and ease of preparation, faces challenges in stability and efficiency. To address this, we synthesized cationic amphiphiles from amino acids (arginine, lysine, and histidine). Histidine emerged as the superior candidate, leading to the development of three histidine-rich cationic amphiphiles for liposomes. Using the hydration method, we have prepared the liposomes and determined the optimal N/P ratios for lipoplex formation via gel electrophoresis. In vitro transfection assays compared the efficacy of our lipids to Fugene, while MTT assays gauged biocompatibility across cancer cell lines (MDA-MB 231 and MCF-7). The histidine-based lipid demonstrated marked potential in enhancing drug and nucleic acid delivery. This improvement stemmed from increased zeta potential, enhancing electrostatic interactions with nucleic acids and cellular uptake. Our findings underscore histidine's crucial role over lysine and arginine for effective delivery, revealing a significant correlation between histidine abundance and optimal performance. This study paves the way for histidine-enriched lipids as promising candidates for efficient drug and nucleic acid delivery, addressing key challenges in the field.

Recent progress in polymeric gene vectors: Delivery mechanisms, molecular designs, and applications

Gene therapy and gene delivery have drawn extensive attention in recent years especially when the COVID-19 mRNA vaccines were developed to prevent severe symptoms caused by the corona virus. Delivering genes, such as DNA and RNA into cells, is the crucial step for successful gene therapy and remains a bottleneck. To address this issue, vehicles (vectors) that can load and deliver genes into cells are developed, including viral and non-viral vectors. Although viral gene vectors have considerable transfection efficiency and lipid-based gene vectors become popular since the application of COVID-19 vaccines, their potential issues including immunologic and biological safety concerns limited their applications. Alternatively, polymeric gene vectors are safer, cheaper, and more versatile compared to viral and lipid-based vectors. In recent years, various polymeric gene vectors with well-designed molecules were developed, achieving either high transfection efficiency or showing advantages in certain applications. In this review, we summarize the recent progress in polymeric gene vectors including the transfection mechanisms, molecular designs, and biomedical applications. Commercially available polymeric gene vectors/reagents are also introduced. Researchers in this field have never stopped seeking safe and efficient polymeric gene vectors via rational molecular designs and biomedical evaluations. The achievements in recent years have significantly accelerated the progress of polymeric gene vectors toward clinical applications.

Synthetic Conjugated Oligoelectrolytes Are Effective siRNA Transfection Carriers: Relevance to Pancreatic Cancer Gene Therapy

Conjugated oligoelectrolyte COE-S6 contains an elongated conjugated core with three cationic charges at each termini of the internal core. As an analogue of bolaamphiphiles, these structural attributes lead to the formation of spherical nanoplexes with Dh = 205 ± 5.0 nm upon mixing with small interfering RNA (siRNA). COE-S6/siRNA nanocomplexes were shown to be protective toward RNase, stimulate endosome escape, and achieve transfection efficiencies comparable to those achieved with commercially available LIP3000. Moreover, COE-S6/siRNA nanocomplexes enabled efficient silencing of the K-ras gene in pancreatic cancer cells and significant inhibition of cancer tumor growth with negligible in vitro toxicities. More importantly, cell invasion and colony formation of the Panc-1 cells were significantly inhibited, and apoptosis of the pancreatic cancer cells was also promoted. We also note that COE-S6 is much less toxic relative to commercial lipid formulations, and it provides optical signatures that can enable subsequent mechanistic work without the need to label nucleotides. COE-S6-based nanoplexes are thus a promising candidate as nonviral vectors for gene delivery.

Nanocarrier-delivered small interfering RNA for chemoresistant ovarian cancer therapy

Ovarian cancer is the fifth leading cause of cancer-related death in women in the United States. Because success in early screening is limited, and most patients with advanced disease develop resistance to multiple treatment modalities, the overall prognosis of ovarian cancer is poor. Despite the revolutionary role of surgery and chemotherapy in curing ovarian cancer, recurrence remains a major challenge in treatment. Thus, improving our understanding of the pathogenesis of ovarian cancer is essential for developing more effective treatments. In this review, we analyze the underlying molecular mechanisms leading to chemotherapy resistance. We discuss the clinical benefits and potential challenges of using nanocarrier-delivered small interfering RNA to treat chemotherapy-resistant ovarian cancer. We aim to elicit collaborative studies on nanocarrier-delivered small interfering RNA to improve the long-term survival rate and quality of life of patients with ovarian cancer. This article is categorized under: RNA Methods > RNA Nanotechnology Regulatory RNAs/RNAi/Riboswitches > RNAi: Mechanisms of Action.