Non-Covalent Linkage of Helper Functions to Dumbbell-Shaped DNA Vectors for Targeted Delivery

Area of Science:

• Molecular Biology
• Gene Therapy
• Nanotechnology

Background:

• Viral vectors pose safety risks in gene therapy.
• Non-viral DNA vectors like plasmids and minicircles have limitations.
• Dumbbell-shaped DNA vectors offer a stable and safe alternative with conjugation potential.

Purpose of the Study:

• To investigate the non-covalent linkage of targeting ligands to dumbbell DNA vectors.
• To evaluate the efficacy of these conjugates for targeted gene delivery to hepatocytes and cancer cells.
• To explore the potential of dumbbell vectors in targeted gene therapeutic applications.

Main Methods:

• Conjugation of tri-antennary N-acetylgalactosamine (GalNAc3) or aptCD137-2 to extended dumbbell vector loops via complementary oligonucleotides.
• Assessment of gene expression in HepG2 cells following delivery of dumbbell-GalNAc3 conjugates.
• In vitro confirmation of RNaseH-mediated linker cleavage for RNA oligonucleotide-linked conjugates.
• Evaluation of cell death induction by dumbbell vectors expressing suicide RNAs in liver cancer cells.

Main Results:

• Dumbbell loop enlargement did not impede gene expression.
• Successful attachment of GalNAc3 and aptCD137-2 to dumbbell vectors.
• Comparable uptake of DNA and RNA oligonucleotide-linked dumbbell-GalNAc3 conjugates by HepG2 cells.
• RNA-linked conjugates showed slightly higher gene expression, attributed to RNaseH-mediated release and nuclear targeting.
• Dumbbell conjugates with GalNAc3 induced significant liver cancer cell death.

Conclusions:

• Dumbbell DNA vectors can be effectively conjugated with targeting ligands like GalNAc3 using complementary oligonucleotides.
• RNaseH-mediated cleavage of RNA linkers enhances gene expression by facilitating dumbbell release and nuclear targeting.
• Dumbbell vector conjugates demonstrate potential for targeted gene delivery and therapeutic applications, particularly in liver cancer treatment.