Chemically Inducible Antisense Oligonucleotides for Cell-Specific Gene Silencing

Abstract

The ability of cell-specific control of the function of antisense oligonucleotides (ASO) is highly desirable for precise gene therapy with minimizing adverse effect in normal cells. Here we report a novel class of chemically inducible ASO (iASOs) that achieve tumor cell-selective gene silencing through hydrogen peroxide (H₂O₂)-triggered activation. By post-synthetic incorporating phenylboronic acid (BO) caging groups at backbone positions, we developed iASOs that remain functionally inactive until H₂O₂-triggered removal of BO groups caused activation. Using EGFP as a reporter system, we demonstrate that the optimal BO-modified iASO exhibited slight gene silencing activity in normal cells but achieves >80% target mRNA knockdown in tumor cells. The BO-modified iASO was further applied to target endogenous Bcl2 gene, demonstrating its ability for controlled gene silencing and cell death. This work establishes a simple and effective platform for conditional gene regulation and the development of cell-specific ASO therapeutics.