G-Quadruplex mRNAs Silencing with Inducible Ribonuclease Targeting Chimera for Precision Tumor Therapy.

Ribonuclease targeting chimera (RIBOTAC) represents an emerging strategy for targeted therapy. However, RIBOTAC that is selectively activated by bio-orthogonal or cell-specific triggers has not been explored. We developed a strategy of inducible RIBOTAC (iRIBOTAC) that enables on-demand degradation of G-quadruplex (G4) RNAs for precision cancer therapy. iRIBOTAC is designed by coupling an RNA G4 binder with a caged ribonuclease recruiter, which can be decaged by a bio-orthogonal reaction, tumor-specific enzyme, or metabolite. A bivalent G4 binder is engineered by conjugating a near-infrared (NIR) fluorescence G4 ligand to a noncompetitive G4 ligand, conferring fluorescence activation on binding G4s with synergistically enhanced affinity. iRIBOTAC is demonstrated to greatly knockdown G4 RNAs upon activation under bio-orthogonal or cell-specific stimulus, with dysregulation of gene expressions involving cell killing, channel regulator activity, and metabolism as revealed by RNA sequencing. This strategy also shows a crucial effect on cell fate with remarkable biochemical hallmarks of apoptosis. Mice model studies demonstrate that iRIBOTAC allows selective imaging and growth suppression of tumors with bio-orthogonal and tumor-specific controls, highlighting G4 RNA targeting and inducible silencing as a valuable RIBOTAC paradigm for cancer therapy.