SMC247-9

(DL)-3,5-Dimethyltyrosine (SMC247-9) is a selective APOBEC3B inhibitor optimized from SMC247, with an IC₅₀ of 50 pM. (DL)-3,5-Dimethyltyrosine binds to the APOBEC3B protein, reduces intracellular APOBEC3B protein abundance partially through a lysosome-dependent pathway, enhances IL-15 expression in tumor cells, and relieves the suppression of CD8 ⁺ T cells by tumor cells in an IL-15-dependent manner. (DL)-3,5-Dimethyltyrosine attenuates tumor- and macrophage-derived chemokine-mediated macrophage chemotaxis and inhibits pathological myeloid inflammatory signaling. (DL)-3,5-Dimethyltyrosine inhibits tumor growth in the immune checkpoint blockade-responsive MC38 syngeneic mouse model and produces synergistic effects with anti-PD-L1 in the immune checkpoint blockade-resistant TC-1 tumor model; it also ameliorates anti-PD-1-exacerbated DSS-induced colitis-like intestinal inflammatory injury. (DL)-3,5-Dimethyltyrosine can be used in research related to tumor immunotherapy .