Self-Initiated Nano-Micelles Mediated Covalent Modification of mRNA for Labeling and Treatment of Tumors.

As a promising gene therapy strategy, controllable small molecule-mRNA covalent modification in tumor cells could be initiated by singlet oxygen (¹O₂) to complete the modification process. However, in vivo generation of ¹O₂ is usually dependent on excitation of external light, and the limited light penetration of tissues greatly interferes the development of deep tumor photo therapy. Here, we constructed a tumor-targeting nano-micelle for the spontaneous intracellular generation of ¹O₂ without the need for external light, and inducing a high level of covalent modification of mRNA in tumor cells. Luminol and Ce6 were chemically bonded to produce ¹O₂ by chemiluminescence resonance energy transfer (CRET) triggered by high levels of hydrogen peroxide (H₂O₂) in the tumor microenvironment (TME). The sufficient ¹O₂ oxidized the loaded furan to highly reactive dicarbonyl moiety, which underwent cycloaddition reaction with adenine (A), cytosine (C) or guanine (G) on the mRNA for interfering with the tumor cell protein expression, thereby inhibiting tumor progression. In vitro and in vivo experiments demonstrated that this self-initiated gene therapy nano-micelle could induce covalent modification of mRNA by ¹O₂ without external light, and the process could be monitored in real time by fluorescence imaging, which provided an effective strategy for RNA-based tumor gene therapy.