Ultrasound-controlled Cancer Immunotherapy using DNA Nanostructures

• Applicant: Professor Dr. Andreas Herrmann
• Subject Area: Pharmacy ; Biomaterials ; Immunology ; Polymer Materials
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 464121872

This project aims to develop a novel advanced drug delivery system (DDS), to be used for cancer immunotherapy. This DDS will be responsive to ultrasound. Ultrasound is the trigger of choice due to many advantages over other types of stimuli, such as deeper penetration ability and minimal invasiveness. The drugs to be delivered are short single stranded DNA oligomers, named CpG oligodeoxynucleotides (CpG ODNs). These ODNs are recognized by Toll-like Receptor 9 (TLR9) in certain types of immune cells (i.e. antigen presenting cells), which in turn activate T-cells to become cytotoxic and exert anticancer activity to eliminate tumour cells. Towards this end, there are three key objectives. First is the fabrication of the DDS. The vehicle that will carry and protect the ODNs is based on a hydrogel composed of long polymers of single stranded DNA (ssDNA), which can be engineered to have multiple functionalities. The ssDNA will be produced enzymatically using a process known as Rolling Circle Amplification (RCA). The product undergoes a process of liquid crystallization that yields unique 3D structures in the shape of flowers, with diameters in the nano- and the micrometre size range. Those nanoflowers have the capacity to hybridize and bind to ODNs and hold them in the inactive state until being activated by ultrasound. Ultrasound produces cavitation bubbles in solution, which collapse and exert shear forces that result in polymer fragmentation. At this stage, we aim to optimize the DDS binding capacity and responsiveness to ultrasound in different frequency and power ranges. Second, the DDS will be tested in-vitro and ex-vivo. For in-vitro testing, we will use a genetically engineered reporter cell line that expresses TLR9 exclusively among the TLR family proteins. The DDS will be tested in its inactive state prior to sonication, and then in its activated state after sonication. After that, the system will be tested ex-vivo, using primary immune cells isolated from human donors’ blood samples, such as macrophages and dendritic cells. The aim at this stage is to demonstrate the activation of these cells by the ultrasound-triggered DDS, then their capability of activating T-cells (also isolated from human blood samples), which in turn produce the desired anticancer activity. Finally, we aim to evaluate the DDS performance in animal models in-vivo (i.e. mice B16 melanoma model). We will study two routes of administration (subcutaneous and intra-tumour), and two doses will be administered at days 7 and 14 after tumour cell injection. At certain time points, the DDS performance will be evaluated by analysis of blood samples and harvested spleens. This will be done for the two states: the inactive DDS after administration, and the activated DDS after exposure to ultrasound at the tumour site. Finally, the tumour size will be measured and evaluated during treatment.

• DFG Programme: Research Grants
• International Connection: South Korea
• Co-Investigators: Privatdozent Matthias Bartneck, Ph.D.; Professor Dr. Fabian Kiessling
• Cooperation Partner: Professor Jun-O Jin, Ph.D.