BPS2026 – Design of DNA-peptide nanostructures against intracellular targets in cancer

Cell signaling pathways have been shown to be disrupted in cancer cells, leading to uncontrolled growth and proliferation. One promising approach for the development of effective cancer treatments is to target specific proteins involved in these pathways and control their activity. In this project we are designing peptide-functionalized DNA nanostructures targeting the intracellular tankyrase proteins for inhibition, which are protein regulators of the Wnt signaling pathway. The DNA nanostructures act as a drug delivery vehicle for the tankyrase inhibitor peptides. They are synthesized by predictably folding a long single-stranded DNA scaffold with shorter complementary DNA strands, and are easily functionalized with fluorophores and active molecules to a high degree of multivalency. We have successfully loaded DNA nanostructures of two different geometries with peptides using azide-DBCO click chemistry. HeLa cells and the Wnt-active cell line SW480 readily uptake non-functionalized DNA nanostructures, as well as the DNA nanostructures that carry the tankyrase-binding peptide. Using super-resolution microscopy, we show that the DNA nanostructures are primarily localized within the lysosomes after 24 h incubation. Moreover, diffuse signal that does not colocalize with the lysosomes can also be detected near the periphery of the cells. The peptide-functionalized nanostructures efficiently inhibit the Wnt pathway, in a comparable degree to known small molecule tankyrase inihibitors. Our work in progress involves thoroughly characterizing the endocytosis mechanism of the nanostructures.