Stimulus-activated ribonuclease targeting chimeras for tumor microenvironment activated cancer therapy

RNA degradation using ribonuclease targeting chimeras (RiboTACs) is a promising approach for cancer therapy. However, potential off-target degradation is a serious issue. Here, a RiboTAC is designed for tumor microenvironment triggered activation. The tumor microenvironment activated RiboTAC (TaRiboTAC) incorporates two pre-miR-21 binders, a near-infrared fluorophore IR780, an RGD targeting peptide and a phenylboronic acid caged ribonuclease recruiter. The caged ribonuclease recruiter is embedded in the molecule and exposed in acidic pH, the phenylboronic acid cage is removed by H2O2 making the TaRiboTAC responsive to the acidic and high H2O2 levels in the tumor microenvironment. It is shown the TaRiboTAC targets tumor tissue and degrades pre-miR-21. The degradation of pre-miR-21 by TaRiboTACs significantly increases the radiotherapeutic susceptibility of cancer cells achieving efficient suppression of human lung adenocarcinoma A549 tumors in living mice. Off-target effects have limited RNA degradation approaches. Here, the authors develop a tumor microenvironment-activated ribonuclease targeting chimera (RiboTAC) demonstrating H2O2 and acid activated degradation of pre-miR-21, which was effective in restoring radiosensitivity in lung cancer.