Abstract
AND Box - A DNA Origami-Based Immunotherapy for Prostate Cancer
As the second most common cancer in males, prostate cancer presents significant therapeutic challenges. Leading conventional immunotherapies, such as CAR-T-cell therapies, face obstacles in tumour site infiltration due to insufficient tumoural antigen heterogeneity and concentration. To overcome these issues with current immunotherapies, we designed the AND box, a targeted DNA nanostructure engineered to enhance T-cell mediated cancer cell elimination. Our box uses an aptamer-based lock mechanism to ensure specificity to prostate cancer cells while preventing off-target T-cell activation.
The box requires two aptamers to bind to overexpressed receptors on prostate cancer cells — prostate-specific membrane antigens (PSMAs) — in an AND-logic mechanism to help differentiate aberrant cells from normal prostate cells. Upon binding to both PSMAs, the box unhinges to reveal an anti-CD3 antibody, which activates T-cells through the T-cell receptor (TCR)-CD3 complex. The activated T-cells then trigger an adaptive immune response.
The AND box was designed in Cadnano© and demonstrated high conformational stability in CanDo©. Additionally, Haddock© simulations indicated favourable docking of the anti-CD3 antibody to the box. Computationally, our design demonstrated a high binding affinity for prostate cancer when delivered intratumorally. Cryo-EM imaging and gel electrophoresis were used to validate the formation of the box. ELISA assays were used to verify the box’s binding affinity to PSMA. To finalize the design, anti-CD3 antibody docking is mediated by –histidine interactions in the box cavity. We aim to advance this design toward a future immunotherapeutic, with the potential to enhance current treatment strategies.