Identification of a myosin 1B-binding aptamer for fluorescence imaging and targeted therapy of esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC), a prevalent subtype of esophageal cancer, poses a significant global health challenge. The current diagnostic and therapeutic approaches for ESCC are inadequate, highlighting the urgent need for the development of novel recognition molecules and the identification of new therapeutic targets to facilitate early diagnosis and targeted therapy. In this work, several aptamers with high affinity to target KYSE30 cells are screened through Cell-based Systematic Evolution of Ligands by EXponential enrichment (Cell-SELEX). These aptamers show distinct binding to multiple cancer cells including ESCC, gastric cancer and liver cancer cells. Meanwhile, a truncated aptamer Z4-6 that retains comparable binding affinity is achieved via sequence optimization. With Z2 and Z4-6 aptamers as the recognition elements, Cy5-labeled fluorescent aptamer probes have demonstrated the ability to specifically recognize ESCC tissues while sparing adjacent non-cancerous tissues, suggesting their potential utility as detection probes in the clinical diagnosis of ESCC. Furthermore, myosin 1B has been identified as the molecular target of the aptamer Z4-6 through pull-down and RNA interference assays, underscoring its promise as a tumor biomarker and therapeutic target. The Z4-6 aptamer has been employed to construct Z4-6-Dox conjugates via noncovalent loading with doxorubicin (Dox) for the targeted therapy of ESCC. In vitro cytotoxicity assays have revealed that Z4-6-Dox selectively induces cytotoxicity in KYSE30 cells. Notably, the Z4-6 aptamer demonstrates in vivo tumor-targeting capabilities, and Z4-6-Dox effectively inhibits tumor cell growth with reduced cardiotoxicity. This study contributes valuable molecular recognition tools and identifies a potential target for the precise diagnosis and targeted therapy of ESCC.