A telomerase-responsive nanoprobe with theranostic properties in tumor cells

Multidrug resistance (MDR) is the main cause of treatment failure in clinical cancer chemotherapy due to the presence of P-glycoproteins (P-gp), which widely exist in stubborn drug-resistant tumor membranes and actively pump drugs from inside the tumor cell to the outside. In this study, we report a novel telomerase-responsive nanoprobe with theranostic properties for inhibiting P-gp expression and reversing MDR by gene silencing. This nanoprobe is composed of an AuNP assembled with telomerase primer, antisense oligonucleotide (ASO), and doxorubicin (Dox). When the designed nanoprobe is uptaken by the MDR cancer cells, the Dox and ASO are specifically released due to the extension of telomerase primer triggered by telomerase. The released ASO specifically hybridizes with multidrug resistance 1 (MDR1) mRNA sequence, which encodes the P-gp. As a result, the expression of P-gp is inhibited and the efflux of Dox is prevented with reduced MDR in cancerous cells. The results demonstrate that the nanoprobe based on telomerase switching for drug release and gene silencing, can both target cancer cells for delivering drugs and overcome the effect of efflux pumps. This work presents a novel paradigm for theranostics of MDR cancer and enhances the efficacy of chemotherapeutics.