Feasibility
Our design is a DNA origami box incorporating multiple components (e.g. anti-CD3 immune engager, RNA aptamer) and is formed as the result of several biochemical reactions (e.g., DNA/RNA hybridization, nickel-nitrilotriacetic acid conjugation), necessitating a considerable amount of preliminary testing, optimization and validation for each component to come together as an integrated system. Despite these challenges, we believe that our solution is achievable with careful planning and execution. Many of the individual components contributing to our system have been well-researched in literature (Ouyang et al, 2017 & Anderson, 2009), providing the benefit of a stable foundation to build upon. To optimize this project’s feasibility, it was a priority to develop an initial proof-of-concept for our system while still ensuring therapeutic efficacy. We had initially intended on attaching two different aptamers to target two highly expressed receptors (PSMA and NTSR1) on the prostate cancer cells for better binding specificity. This design was ultimately simplified to using two identical aptamers targeting the PSMA receptor due to the costs with the NTSR1 protein and the associated RNA aptamer, along with the plethora of additional experimental iterations that were deemed secondary at this stage of research and design.
Immunotherapy Applications
In terms of the feasibility of our system as a prostate cancer immunotherapy, various aspects indicate potential for success. Compared to other DNA assembly methods, DNA origami often demonstrates higher yield, durability, and capability to build more intricate, non-periodic products (Ghosal et al., 2023). Additionally, its programmable nature allows for computer aided designs and universal synthesis procedures, making it an accurate and docile technology. Its limited stability in biological fluids along with its susceptibility to chemical and enzymatic breakdown, however, remain the primary concerns for real-world applications (Ghosal et al., 2023). Concerning the RNA aptamers attached to the box, these oligonucleotides effectively bind to targets with high affinity and specificity (Germer et al., 2013). Aptamers typically exhibit little to no immunogenicity, higher stability and likelihood to achieve desired folding, and are much easier to synthesize compared to other macromolecules. Additionally, their ability to conjugate additional ligands make them an attractive molecule for targeted delivery, which we have leveraged. Beyond our system, there are certainly limitations that may hinder the feasibility of our project. One particular issue includes the lack of reliable animal models to predict clinical efficacy (Pandiella et al., 2023). Furthermore, target mediated drug disposition (TMDD), anti-drug antibodies (ADAs), and side effects pertinent with T-cell activators/engagers (e.g., cytokine release syndrome, neurologic toxicity) all influence the safety of new immuno-oncogenic agents and are difficult to predict with in vitro modeling (Pandiella et al., 2023).