Targeted photodynamic therapy of cancer using a novel gallium (III) tris (ethoxycarbonyl) corrole conjugated‐mAb directed against cancer/testis antigens 83

Photodynamic therapy (PDT) is a noninvasive, highly selective approach to the treatment of tumors. However, its therapeutic effect is limited by long‐lasting skin phototoxicity. Therefore, to compromise this shortcoming, it is preferable to deliver photosensitizers selectively to tumor cells with the aid of antibodies specific against tumor‐associated antigens. Cancer/testis antigens 83 (CT83), also called KK‐LC‐1 or CXorf61, recognized by cytotoxic T lymphocytes (CTL), has become a promising target for immunotherapy. Herein, we developed and characterized a novel mouse CT83 mAb 7G4 with a high affinity with Gallium (III) 5, 10, 15‐tris (ethoxycarbonyl) corrole (1‐Ga), a new and promising photosensitizer in PDT. The enzyme‐linked immunosorbent assay (ELISA), flow cytometry and cytotoxicity activity assays revealed that 7G4‐1‐Ga was able to recognize human CT83 with high specificity. Furthermore, 7G4‐1‐Ga showed greater cytotoxicity to CT83‐expressing human cancer cells in vitro than 1‐Ga. These results suggest that the antibody‐conjugated photosensitizer between anti‐CT83 mAb and 1‐Ga may have a good application in PDT, where the destruction of CT83‐expressing tumor is required.