click-to-cure · Exploitation of bioorthogonal click-to-release chemistry for precision cancer therapy

Targeted cancer therapies are crucial for effective treatment of people suffering from this often-devastating disease. However, most of the available drugs come with severe side effects that lower the patient's quality of life and limit the maximum applicable dose, particularly for radioligand therapy. This is due to the lack of tumor specificity and accumulation of the drug in healthy tissue. Low-energy Auger electrons induce extensive DNA damage and exhibit very low cellular toxicity during transit in the body. However, it is very challenging to specifically deliver Auger emitters to the nucleus as the chemical properties for nuclear penetrations contradict cancer specificity. Here, I want to develop a double targeting strategy using a bioorthogonal click-to-release reaction to deliver Auger emitters to the DNA of metastatic castration-resistant prostate cancer cells. Inhibitors of the DNA repair enzyme PARP will be tagged with both an Auger emitter and a prostate-specific membrane antigen (PSMA)-targeting moiety via a trans cyclooctene linker. A complementary tumor-specific ligand targeting the gastrin-releasing peptide receptor carries a tetrazine release moiety. Only upon internalization of both the PSMA-drug conjugate and the release molecule into the cancer cells, the active drug is released from the PSMA targeting moiety and localizes to the nucleus. After synthesis and radiolabeling of the compounds, the strategy will be tested first in suitable prostate cancer cells in vitro, and then translated to an in vivo therapy study in rodents. If successful, the project will lay the foundation to apply the concept to other cancer entities with suitable complementary markers. This novel strategy to treat cancer with minimal damage to healthy tissue will not only boost the efficacy of the therapy due to higher applicable doses, but also tremendously improve the quality of life for the patients.