A non-G-Quadruplex DNA Aptamer Targeting NCL for Diagnosis and Therapy in Bladder Cancer.

Bladder cancer (BC) is a highly aggressive malignant tumor affecting the urinary system, characterized by metastasis and a poor prognosis that often leads to limited therapeutic success. In this study, we aimed to develop a novel DNA aptamer for the diagnosis and treatment of BC using a tissue-based systematic evolution of ligands by exponential enrichment (SELEX) process. SELEX involves the in vitro evolution of aptamers through iterative selection, allowing the identification of high-affinity aptamers that specifically bind to target molecules from a large pool of oligonucleotides. By employing SELEX, we successfully generated a new aptamer named TB-5, which demonstrated a remarkable affinity for nucleolin (NCL) in BC tissues, surpassing the binding affinity observed in normal tissues by over four-fold. Furthermore, TB-5 displayed marked biocompatibility both in vitro and in vivo. To validate NCL as a reliable tissue-specific biomarker, immunohistochemical staining was performed. Circular dichroism spectroscopy revealed that TB-5 adopts a non-G-quadruplex structure, distinguishing it from the current aptamer AS1411, which also binds to NCL. Interestingly, TB-5 exhibited a distinct binding region on NCL compared to AS1411. Notably, our study revealed that TB-5 activates NCL function by promoting autophagy and suppressing the migration and invasion of BC cells, shedding light on the interplay between steric hindrance and NCL biological function. Most importantly, we discovered that TB-5 disrupts mRNA transcription processes in cancer cells by binding to NCL, leading to the inhibition of cell proliferation and migration. These findings highlight the critical role of NCL in the pathological examination of BC and warrant more comprehensive investigations on anti-NCL aptamers in BC imaging and treatment. This article is protected by copyright. All rights reserved.