Local Immune‐Triggered Surface‐Modified Stem Cells for Solid Tumor Immunotherapy

Here, described are additional treatment strategies that make use of human mesenchymal stem cell (hMSC)‐based local immunotherapeutic agents for the treatment of solid tumors. Dibenzocyclooctyne‐poly(ethylene glycol)‐pheophorbide A conjugates are engineered for cell surface conjugation by copper‐free click chemistry and are subsequently conjugated to hMSC (hMSC‐DPP). hMSC‐DPP can recognize and migrate toward cancer lesions, where they secrete pro‐inflammatory cytokines such as interleukin (IL)‐6, IL‐8, and heat shock protein 70 in pursuance of photodynamic therapy‐mediated cell death. The secreted immune factors trigger interferon gamma, IL‐2, IL‐4, IL‐12, and granulocyte‐macrophage colony‐stimulating factor, resulting in the local accumulation of T cells, B cells, natural killer cells, and antigen presenting cells at the tumor site. Treatment with hMSC‐DPP induces the accumulation of cytokines at the cancer site and minimizes systemic immune‐based side effects. This strategy is expected to increase the vulnerability of cancer cells to immune cells and cytokines, thus aiding in the development of a robust treatment platform for cancer immunotherapy. Photosensitizer‐conjugated human mesenchymal stem cells can recognize and migrate toward cancer lesions, where they secrete pro‐inflammatory cytokines such as interleukin‐6, interleukin‐8, and Hsp70 in pursuance of photodynamic therapy‐mediated cell death. This strategy is expected to increase the vulnerability of cancer cells to immune cells and cytokines, thus aiding in the development of a robust treatment platform for cancer immunotherapy.