DNA-Based Nanomedicine with Targeting and Enhancement of Therapeutic Efficacy of Breast Cancer Cells.

Recently, a DNA tetrahedron has been reported to be a novel nanomedicine and promising drug vector because of its compactness, biocompatibility, biosafety, and editability. Here, we modified the DNA tetrahedron with a DNA aptamer (AS1411) as a DNA-based delivery system, which could bind to nucleolin for its cancer cell selectivity. Nucleolin is a specific biomarker protein overexpressed on membranes of malignant cancer cells and its deregulation is implicated in cell proliferation. The antimetabolite drug 5-fluorouracil (5-FU) is an extensively used anticancer agent; however, its major limitation is the lack of target specificity. Cyanine 5 (Cy5), a fluorescent probe, can be used to label DNA tetrahedron and enhance photostability with minimal effects on its basic functions. In this study, we additionally attached 5-FU to the DNA-based delivery system as a new tumor-targeting nanomedicine (AS1411-T-5-FU) to enhance the therapeutic efficacy and targeting of breast cancer. We examined the difference of the cellular uptake of AS1411-T-5-FU between breast cancer cells and normal breast cells and concluded that AS1411-T-5-FU had a better targeting ability to kill breast cancer cells than 5-FU. We further evaluated the expressions of cell apoptosis-related proteins and genes, which are associated with the mitochondrial apoptotic pathway. Ultimately, our results suggest the potential of DNA tetrahedron in cancer therapies, and we develop a novel approach to endow 5-FU with targeting property.