Background
Prostate Cancer
Prostate cancer (PCa) is one of the most commonly diagnosed cancers worldwide and is a leading cause of cancer death in men (Leslie et al., 2024). In 2020, it accounted for 7.8% of all new cancer cases and 15.1% of new cancer cases in men worldwide. Of the 1,414,259 new cases that year, about 1 in 44 men will have passed due to the disease (American Cancer Society, 2024). Though the incidence of the disease is high, most prostate cancers tend to grow slowly and with limited aggressiveness. It first develops in the cells of the prostate, and while confined to this gland, there is a low risk of serious harm. Patients have the best chance at a successful treatment if the cancer is caught at an early stage, before the cancer spreads to the rest of the body (metastasis). Once PCa has spread to other organs in the body, it can still be treated and controlled but it is unlikely the patient can be cured (Mayo Clinic, 2024). If the cancer spreads to the bones, the 5-year survival rate drops from nearly 100% to 29% (WebMD, 2023).
There are a number of biomarkers that are used in the detection and treatment of PCa. An important biomarker targeted in the treatment of cancer is prostate-specific membrane antigen (PSMA), a transmembrane protein that is expressed on the surface cancer cells in the prostate. This protein is expressed 100 to 1000 times more in cancer cells than in benign and non-prostate cells - this makes it a promising target for the diagnosis and treatment of PCa (Donin & Reiter, 2018). The structure of PSMA also lends itself to easy targeting by antibodies and small-molecule ligands as it has an extracellular domain (a region existing on the outside of the cell) with well-characterized binding sites (Donin & Reiter, 2018). PSMA has also found its use in the diagnosis and staging of PCa by way of positron emission tomography-computed tomography (PET-CT) scanning. In a clinical trial, a PSMA PET-CT scan showed 27% more accuracy in detecting any metastases of PCa than the standard approach (92% versus 65%). These imaging results could contribute to the diagnosis and staging of the disease, as well as guide clinicians in their treatment plans (National Cancer Institute, 2020).
Emergence of Nanotechnology in Immunotherapy
In recent years, the use of nanotechnology in cancer therapy has surged in popularity. Nanotechnology provides a vehicle for drugs to directly and selectively target cancerous cells, overcome drug resistance, and enable the use of novel immunotherapies (National Cancer Institute, 2023). Among the many different forms of nanotechnology, DNA origami holds great promise. DNA is a biomolecule – a building block of life. Thus, it has excellent biocompatibility and in vivo stability (Zhang et al., 2023). The selectivity of Watson-Crick base pairing between single strands of DNA can be exploited to facilitate their folding and assembly into complex 2D or 3D structures. This principle, in conjunction with the programmability of DNA technology, allows the sequence of base pairs on the template DNA strand to be edited to produce a desired nanostructure. Short strands of DNA called staple strands can be used to hold the structure together, like how staples hold paper (Zhang et al., 2023). That is the concept of DNA origami. The result is a highly editable, self-assembling, and stable structure that can be used in a variety of applications, including immunotherapy.