Highly Sensitive and Specific Detection of Autophagy Signaling Pathway in Live Cancer Cells for Chemoresistance...

The identification and detection of specific autophagy signaling pathways in live cancer cells are critical to modulate chemotherapy sensitivity in cancer treatments. However, conventional autophagy signaling pathway detection approaches are challenged by specificity and sensitivity. Here, with the synthesis of ZnO nanoparticle (NP)-DNA nanospheres (ZnO-DNA NSs) using palindromic DNA sequence scaffolds, we propose a new strategy for sensitive detection of a specific autophagy signaling pathway in cancer cells via simultaneously imaging the upstream miRNA-34a and downstream autophagy-related 4B cysteine peptidase (ATG4B). The miRNA-34a-responsive, Zn²⁺-dependent I-R3 DNAzyme (I-Dz) and ATG4B-specific peptide-DNA signal probes are integrated into the ZnO-DNA NSs. Upon readily being delivered into cancer cells, the acid microenvironment leads to the dissolution of ZnO NPs to release the Zn²⁺ cofactor for I-Dz. Subsequently, miRNA-34a and ATG4B initiated cyclic cleavage of the signal probes to yield distinct fluorescence for highly sensitive detection of miRNA-34a and ATG4B, thereby achieving specific autophagy pathway detection. Besides, the dynamic concentration interplay between miRNA-34a and ATG4B upon drug stimulation can also be monitored by the ZnO-DNA NSs to realize effective discrimination of drug-sensitive and -resistant cancer cells to access chemoresistance reversion, revealing the robust potential of ZnO-DNA NSs for detecting different autophagy pathways and screening potent therapeutic drugs.