Telomerase-Responsive CRISPR System-Regulated Nanobomb for Triggering Research on Telomerase “Self-Detonation”

Targeting tumor markers is one of the most important approaches to tumor therapy, and the "suicide" pattern of tumor marker response is a very challenging study. Telomerase, as one of the key factors associated with human longevity and cancer progression, is considered to be an emerging biomarker for cancer diagnosis. The targeted drug delivery nanobomb─BIBR1532@HSN/FQDNA/MUC1 aptamer (B@HDA) is prepared in this study based on hollow silica nanoparticles (HSN) and CRISPR systems. Amino-modified FQDNA and amino-modified MUC1 aptamer are covalently attached to the surface of carboxyl-functionalized HSN. The modified MUC1 aptamer directs the nanobomb to specifically target breast cancer cells (MCF-7) and FQDNA sequesters the telomerase inhibitor (BIBR1532) within the HSN. Telomerase primers (TPs) is recognized by the highly expressed telomerase in MCF-7 cells and is elongated to form DNA substrates. The substrate pairs with crRNA bases to effectively activate CRISPR-Cas12a. The activated CRISPR-Cas12a precisely cut FQDNA, releasing BIBR1532, which inhibits telomerase activity. This strategy achieves telomerase "suicide". The nanobomb described above has the following advantages. (1) The "closing" effect of FQDNA contributes to reducing the nonspecific release of BIBR1532. (2) B@HDA, combined with CRISPR, regulates mitochondrial dysfunction and cell senescence in MCF-7 cells. (3) In the tumor-bearing mouse model, B@HDA, combined with CRISPR, exhibits good biocompatibility and an obvious tumor ablation effect on MCF-7 tumors, suggesting potential application prospects across a wide range of cancer cell lines. In summary, the proposed nanobomb provides a tunable switch approach for the specific inhibition of telomerase and the reduction of tumor cell growth, representing a promising avenue for promoting senescence and treating cancer.