RECAST as an enhanced gene delivery system

Background/problem

Gene therapy, a promising tool to explore pathogenesis and a powerful weapon to treat diseases at the genomic level, has been making strides in recent years. It has found use in various applications, from cell therapeutics to treating inherited, and neurodegenerative diseases. However, the current methods of gene (“therapy”, “DNA”) delivery have significant drawbacks. Viral-based approaches are efficient but have several issues. They can trigger immune responses, unstable over the long term, with minimal genetic payloads, and expensive to produce. Alternatively, there are non-viral vectors, but they are less efficient. Efficient gene transfer requires not simply the entry of the therapy from the extracellular surface of the cell into the cytoplasm, but also delivery across the nuclear envelope and into the nucleus.

Despite improvements, the efficiency of non-viral vectors is still lacking for clinical needs. For example, the therapy loses its effectiveness when diluted, but high doses can be toxic. Also, if the DNA load is big (>7 Kbp), it cannot be compact enough for efficient nuclear transport. Current non-viral strategies pack the therapy into nanoparticles and release it into the cell, but most of it degrades before reaching the nucleus. There have been attempts to address these challenges—e.g., by using smaller DNA or attaching proteins to target the nucleus—but these methods are either unstable or too expensive and complicated.

Tech overview/solution

University of Texas at Austin researchers devised RECAST (REversible Covalent Assembly STrategy) to enhance DNA nucleus import and improve efficiency of gene delivery. It condenses the therapy via covalent linkers to achieve a “traceless”, direct-to-nucleus release and delivery. The RECAST strategy involves a two-stage condensation approach.

1. Condensation: The therapy is crosslinked via reversible covalent self-assembly to pack a small size (< 60 nm).
2. Packaging and delivery: The crosslinked therapy is then re-compressed via electrostatic interactions using a cationic system/liposome (~100 nm).

After delivery and release in the cytoplasm, the crosslinked therapy, because of their small size, can easily diffuse towards the nucleus via nuclear pore complex channels.

Benefits/competitive advantage

Key advantages of the RECAST approach include:

• Improved transfection efficiency even for larger DNA load: The smaller size of the condensed DNA (sizes ranging from 6.2 Kbp to ~11.6 Kbp) allows for more efficient diffusion into the nucleus, leading to increased gene transfection efficiency.
• Accurate transcription: The “traceless” release of DNA in the reductive nucleus environment enabled the correct DNA transcription to be initiated, thus achieving enhanced gene transfection efficiency without affecting the accuracy of the transcription.
• Versatility: The crosslinkers used in the RECAST process can be developed not only for gene therapy but also as gene labeling kits. Moreover, the two-stage condensation approach can be used, not only for the delivery of genes, but also proteins and other biomacromolecules.
• Reduced cytotoxicity: High gene delivery efficiency can be achieved even at low concentrations of cationic vectors, reducing the cytotoxicity often associated with high doses of cationic vectors.
• Enhanced organ-selective gene transfection: The RECAST strategy has demonstrated substantial value for non-viral gene delivery in clinical therapeutic applications, particularly in achieving enhanced organ-selective gene transfection.

Opportunity

The market opportunity for technologies related to enhanced gene therapy delivery appears promising over the next 5-10 years. It is poised for growth, driven by scientific advancements and increasing approvals. The global gene delivery technologies market is expected to reach USD 7.9 billion by 2028, expanding at a CAGR of 15.1% from 2021 to 2028. Alternatively, biopharmaceutical and biotechnology industries are also driving demand for better transfection reagents like this technology for cutting edge applications such as 3D cell culture and organoids. The global transfection reagents market was valued at USD 1.19 billion in 2023 and is projected to reach impressive growth, with a CAGR of 9.43% through 2029. By 2031, this market is expected to reach USD 2.54 billion, growing at a CAGR of 9.6%.

For parties/companies with interest in enhanced gene therapy, gene delivery, therapeutics, for cancer and neurological diseases, and transfection reagents