(628e) Evaluating Toxicology, Immunogenicity, Bio-Distribution, and Pharmacokinetics of DNA Origami Nanostructures In Vivo

Scaffolded DNA origami nanotechnology allows for the generation of pre-defined shaped nanoscale objects via molecular self-assembly as well as a robust platform for drug delivery applications. Previous studies reported that DNA origami nanostructures could be functionalized with targeting moieties and effectively loaded with anthracyclines (e.g. doxorubicin and daunorubicin) and thrombin. Furthermore, drug-loaded DNA origami nanostructures were reported to induce an enhanced anti-cancer effect relative to free drug in both solid tumor and hematologic model systems in vitro, while recent findings showed that thrombin-loaded nanostructures induce tumor necrosis and inhibit tumor growth in vivo in a targeted manner. Despite this exciting promise, the toxicology, immunogenicity, bio-distribution, and pharmacokinetics of DNA origami nanostructures in vivo remain ill defined. Here we evaluate two DNA origami nanostructures that vary in shape, a flat-2D triangle and 3D-rod-shaped nanostructure either alone or functionalized with polyethylene-glycol (PEG)-conjugated oligonucleotides. A repeat dosing regimen of unloaded triangle and rod-shaped structures at clinically relevant levels revealed that DNA origami nanostructures were generally non-toxic in vivo as shown by weight and a complete biochemical panel assessing liver function apart from mild hepatic necrosis in mice treated with PEG-coated triangle nanostructures. A modest pro-inflammatory molecular and cellular immune response was evident among mice in all treatment groups, especially among mice treated with triangle/triangle-PEG that dampened by the conclusion of the dosing regimen. Distribution findings showed PEG-functionalized and non-functionalized DNA nanostructures distribute throughout the periphery immediately after i.v. injection and within ~30 minutes after i.p. injection, while myeloid cell populations preferentially internalized DNA nanostructures ex vivo. PEG-functionalized DNA nanostructures demonstrated modest increased stability in vivo relative to unmodified DNA nanostructures via a fluorescence-based live animal in vivo imaging system (IVIS). Taken together, our in vivo findings suggest that DNA origami nanostructures are mostly non-toxic, generate a modest immune response, distribute effectively into the periphery, and, therefore represent a promising novel platform for future cancer drug delivery studies in vivo. Funded in part by start-up funds provided to Dr. Castro by the Department of Mechanical and Aerospace Engineering, The National Institutes of Health-National Cancer Institute-P50-CA140158 and R35-CA197734, The D. Warren Brown Foundation, Four Winds Foundation, and The Harry T. Mangurian Jr. Foundation. C.R.L is a recipient of a National Institutes of Health T32 Award in Oncology Training Fellowship at The Ohio State University Comprehensive Cancer Center, T32-CA009338.