Demethylating therapy increases anti-CD123 CAR T cell cytotoxicity against acute myeloid leukemia

The success of CAR-T cells for treating acute myeloid leukaemia (AML) is hampered by toxicity to normal cells and low CAR-T cell persistence. Here, the authors show that the demethylating compound 5 '-Azacitdine increases anti-CD123 CAR-T cell cytotoxicity against AML. Successful treatment of acute myeloid leukemia (AML) with chimeric antigen receptor (CAR) T cells is hampered by toxicity on normal hematopoietic progenitor cells and low CAR T cell persistence. Here, we develop third-generation anti-CD123 CAR T cells with a humanized CSL362-based ScFv and a CD28-OX40-CD3 zeta intracellular signaling domain. This CAR demonstrates anti-AML activity without affecting the healthy hematopoietic system, or causing epithelial tissue damage in a xenograft model. CD123 expression on leukemia cells increases upon 5 '-Azacitidine (AZA) treatment. AZA treatment of leukemia-bearing mice causes an increase in CTLA-4(negative) anti-CD123 CAR T cell numbers following infusion. Functionally, the CTLA-4(negative) anti-CD123 CAR T cells exhibit superior cytotoxicity against AML cells, accompanied by higher TNF alpha production and enhanced downstream phosphorylation of key T cell activation molecules. Our findings indicate that AZA increases the immunogenicity of AML cells, enhancing recognition and elimination of malignant cells by highly efficient CTLA-4(negative) anti-CD123 CAR T cells.

Automated summary

The success of CAR-T cells in treating AML is constrained by their toxicity to normal cells and low persistence. This study demonstrates that the demethylating compound 5'-Azacitdine can enhance anti-CD123 CAR-T cell cytotoxicity against AML cells. Additionally, the development of third-generation anti-CD123 CAR-T cells shows promising results in targeting AML cells without affecting healthy hematopoietic system.