Selection and characterization of DNA aptamer for metastatic prostate cancer recognition and tissue imaging

Prostate cancer (PCa) is the second leading cause of death and most prevalent cancer in men. The absence of curative options for castration-resistant metastatic prostate cancer and biomarkers able to discriminate between indolent and aggressive tumors contribute to these statistics. In this study, a DNA aptamer termed DML-7 was successfully selected against human PCa cell line DU145 by using the cell-based systematic evolution of ligands by exponential enrichment (SELEX) method. The selected aptamer DML-7 was found to internalize into target cells in a temperature-dependent manner and exhibit high binding affinity for target cells with dissociation constants in the nanomolar range. Binding analysis further revealed that DML-7 only binds to DU145 and PC-3 cells with metastatic potential, but not to LNCaP or 22Rv1 cells with low or nonmetastatic potential, demonstrating that DML-7 has excellent selectivity for the recognition of the metastatic PCa cells. Clinical tissue imaging further confirmed these results. Therefore, both high binding affinity and specificity to metastatic PCa cells and tissues afford DML-7 with the potential for development into a novel tool for diagnosis and targeted drug delivery against metastatic prostate cancer.