Electrochemical detection of FTO with N₃-kethoxal labeling and MazF cleavage

N6-Methyladenosine (m6A) is a prevalent modification in eukaryotic mRNAs and is linked to various human cancers. The fat mass and obesity-associated protein (FTO), a key m6A demethylase, is crucial in m6A regulation, affecting many biological processes and diseases. Detecting FTO is vital for clinical and research applications. Our study leverages the specific cleavage properties of the MazF endoribonuclease to design an electrochemical method with signal amplification guided by streptavidin-horseradish peroxidase (SA-HRP), intended for FTO detection. Initially, the compound N₃-kethoxal is employed for its reversible tagging ability, selectively attaching to guanine (G) bases. Subsequently, dibenzocyclooctyne polyethylene glycol biotin (DBCO-PEG4-Biotin), is introduced through a reaction with N₃-kethoxal. HRP is then employed to catalyze the redox system to enhance the current response further. A promising linear correlation between the peak current and the FTO concentration was observed within the range of 7.90 × 10^-8 to 3.50 × 10^-7 M, with a detection limit of 5.80 × 10^-8 M. Moreover, this method assessed the FTO inhibitor FB23's inhibitory effect, revealing a final IC₅₀ value of 54.73 nM. This result aligns with the IC₅₀ value of 60 nM obtained through alternative methods and is very close to the values reported in the literature. The study provides reference value for research into obesity, diabetes, cancer, and other FTO-related diseases, as well as for the screening of potential therapeutic drugs.