Diselenide–Pemetrexed Assemblies for Combined Cancer Immuno‐, Radio‐, and Chemotherapies

Immunotherapy has emerged as a promising new approach for cancer treatment. However, clinically available drugs have been limited until recently, and the antitumor efficacy of most cancer immunotherapies still needs to be improved. Herein, we develop diselenide–pemetrexed assemblies that combine natural killer (NK) cell‐based cancer immunotherapy with radiotherapy and chemotherapy in a single system. The assemblies are prepared by co‐assembly between pemetrexed and cytosine‐containing diselenide through hydrogen bonds. Under γ‐radiation, the hydrogen bonds are cleaved, resulting in the release of pemetrexed. At the same time, diselenide can be oxidized to seleninic acid, which suppresses the expression of human leukocyte antigen E (HLA‐E) in cancer cells, thus activating the immune response of NK cells. In this way, cancer immunotherapy is combined with radiotherapy and chemotherapy, providing a new strategy for cancer treatment.