Development of Novel Aptamer-Based Targeted Chemotherapy for Bladder Cancer.

Bladder cancer is common worldwide, with most patients presenting with nonmuscle invasive disease. Multiple intravesical recurrences lead to reduced quality of life and high costs for patients with this form of bladder cancer. Intravesical chemotherapy aimed at reducing recurrence is the standard-of-care but has significant side effects from nonspecific cytotoxicity to normal urothelium. Importantly, toxicity limits doses that can be administered. Thus, tumor-specific drug targeting could reduce toxicity and enhance effectiveness by allowing higher doses. Here, using cell internalization systematic evolution of ligands by exponential enrichment (SELEX), we identify a novel bladder cancer-specific, chemically modified nucleic acid aptamer that can be preferentially internalized into tumor cells but not normal urothelial cells. The 35-nucleotide B1 aptamer is internalized into bladder cancer cells through clathrin-mediated endocytosis and macropinocytosis. As proof of principle, a B1-guided DNA nanotrain delivery vehicle for epirubicin was constructed as a targeted intravesical chemotherapy. The B1-nanotrain-epirubicin construct exhibited selective cytotoxicity towards bladder cancer cells and outperformed epirubicin in murine orthotopic xenograft models of human bladder cancer. This aptamer-based delivery system makes targeted chemotherapy possible for bladder cancer, providing a compelling rationale for clinical development. SIGNIFICANCE: These findings identify a bladder cancer-specific aptamer that can be used for targeted delivery of chemotherapy, potentially reducing toxicity and enhancing therapeutic efficacy. ©2022 American Association for Cancer Research.