In vivo molecular imaging of drug resistance in neuroblastoma using APE1 cyclically cleaved and miR-514a self-recycled programmable allosteric DNA nanomachine

Clinical practice has demonstrated that the absence of in vivo drug resistance monitoring strategies for neuroblastoma (NB) contributes to relapse rates exceeding 60 % among children with high-risk NB. These patients frequently miss the optimal therapeutic window for treatment, leading to poor prognoses and ultimately fatal outcomes. Herein, a novel strategy (APII-tFNA) was developed by targeting apurinic/apyrimidinic endonuclease 1 (APE1) and miR-514a for rapidly and spatially in vivo imaging of NB and monitoring NB drug resistance. Both APE1 and miR-514a have been rigorously validated as critical NB drug resistance markers at the clinical NB tissue level. APII-tFNA, the APE1 cyclically cleaved and miR-514a self-recycled programmable allosteric DNA nanomachine, operates via an AND-gated manner. APII-tFNA can hybridize with miR-514a, leading to the formation of the 514a-APII-tFNA complex. Subsequently, the apurinic/apyrimidinic site (AP site) within the 514a-APII-tFNA complex can be specifically cleaved by APE1, leading to spatial separation between fluorophore and quencher, and configurational changes in 514a-APII-tFNA. Simultaneously, APE1 and miR-514a can enter the next reaction cycle to generate more fluorescence signals, thereby enabling the highly sensitive detection of targets. Experimental results demonstrated that this responsive nanomaterial achieved a limit of detection (LOD, 3σ) of 0.25 pM for in vivo molecular imaging of NB drug resistance marker and was able to guide precise surgical excision with superior spatial specificity. This study presents a nanomaterial platform for in vivo molecular imaging of NB and monitoring NB drug resistance, with great potential for improving the survival rate of children with NB.