Fluorescence Imaging Analysis of PTK7 Clustering in Situ via a Programmable DNA Network for Apoptosis Induction and Drug Resistance Reversal

Inducing cell surface receptor clustering to mediate downstream signaling and reverse drug resistance has become a core cancer therapeutic strategy. However, controllable in situ formation of receptor superclusters remains a key bottleneck. To address these issues, a programmable DNA self-assembly strategy was established by integrating three units of rolling circle amplification (RCA) vector unit, two long DNA strands loaded with aptamer recognition units and the hairpin assembly unit. Fluorescence imaging analysis demonstrated that targeting binding to protein tyrosine kinase 7 (PTK7) can trigger the release of an initiator strand, which in turn activated CHA-driven DNA network formation on the cell membrane. This network induced in situ, self-driven clustering of PTK7 receptors, leading to decreased intracellular calcium levels, loss of mitochondrial membrane potential, and activation of the mitochondrial-mediated intrinsic apoptosis pathway. Ultimately, this process promoted tumor cell apoptosis and downregulated the expression of the resistance-related protein P-glycoprotein (P-gp). This study provides a novel tool for drug-resistant tumor therapy and lays a foundation for antitumor therapy innovation.