Development of a Novel DNA Aptamer Targeting Colorectal Cancer Cell-Derived Small Extracellular Vesicles as a Potential Diagnostic and Therapeutic Agent

Colorectal cancer (CRC) as the second leading cause of global cancer deaths poses critical challenges in clinical settings. Cancer-derived small extracellular vesicles (sEVs), which are secreted by cancer cells, have been shown to mediate tumor development, invasion, and even metastasis, and have thus received increasing attention for the development of cancer diagnostic or therapeutic platforms. In the present study, the sEV-targeted systematic evolution of ligands by exponential enrichment (E-SELEX) is developed to generate a high-quality aptamer (CCE-10F) that recognizes and binds to CRC-derived sEVs. Via an in-depth investigation, it is confirmed that this novel aptamer possesses high affinity (K_d = 3.41 nm) for CRC-derived sEVs and exhibits a wide linear range (2.0 × 10⁴ -1.0 × 10⁶ particles µL^-1 ) with a limit of detection (LOD) of 1.0 × 10³ particles µL^-1 . Furthermore, the aptamer discriminates CRC cell-derived sEVs from those derived from normal colon cell, human serum, and other cancer cells, showing high specificity for CRC cell-derived sEVs and significantly suppresses the critical processes of metastasis, including cellular migration, invasion, and angiogenesis, which are originally induced by sEVs themselves. These findings are highly encouraging for the potential use of the aptamer in sEV-based diagnostic and therapeutic applications.