Alpha-Tocopherol-Conjugated DNA Tetrahedron with Enhanced Cellular Uptake and Cytotoxicity for Cancer Therapeutics

Cancer remains one of the most fatal diseases worldwide. Current therapies often lack specificity and cause toxicity to healthy tissues. DNA nanotechnology, an emerging interdisciplinary field, facilitates the design of programmable, biocompatible, and structurally precise DNA-based nanostructures, with promising applications in drug delivery, biosensing, and therapeutics. However, the negatively charged plasma membrane limits the cellular uptake of negatively charged DNA nanostructures. Although strategies such as cationic lipid coating or electrostatic complexation have been explored to enhance DNA stability, these approaches can exhibit heterogeneous lipid coverage and batch-to-batch variability, potentially leading to variable protective efficacy. Furthermore, drug delivery using DNA tetrahedron (TD) or conventional chemotherapies frequently results in off-target effects due to poor drug specificity. To address these challenges, this study explores the conjugation of a hydrophobic molecule, alpha-tocopherol succinate (αT), known for its selective cytotoxicity toward malignant cells over normal cells at appropriate concentrations. In this study, we engineered a hydrophobic TD by conjugating αT (TD_αT) to an amino-modified M1 oligonucleotide using HOBt-EDC amide coupling. This was followed by one-pot self-assembly with complementary strands to form the TD_αT conjugate. The TD_αT conjugate maintained the selective toxicity of αT, and cellular uptake varied between different cancerous and non-cancerous cell lines. TD_αT induced elevated reactive oxygen species (ROS) generation, leading to apoptosis specifically in malignant cells. These findings demonstrate a DNA nanostructure-based delivery platform that combines selective cytotoxicity with improved cellular internalization, offering a promising strategy for targeted cancer therapy.