Intrinsic STING signaling in target AML cells is required for enhancing AMG 330–mediated lysis. (A) Immunoblots of monoclonal HL-60 cell lines of the indicated genotypes generated by CRISPR-Cas9 gene editing. (B) Monoclonal HL-60 cell lines of the indicated genotypes were treated with IFN-α2a, and phosphorylation of STAT1 (pSTAT1) was determined by immunoblotting. (C) Flow cytometric analysis of AMG 330–mediated (5 ng/mL) cytotoxicity after 72 hours against HL-60 cell lines of the indicated genotypes (mean of 2 independent knockout clones) in cocultures with human T cells (E:T, 1:10, n = 3). Specific lysis was calculated relative to the c-BiTE condition. The concentration of added cGAMP in cocultures was 40 μg/mL. (D-E) Levels of IFN-γ (D) and IL-2 (E) as determined by CBA analysis of cocultures of human T cells and wild-type or STING-deficient HL-60 cells in the presence of the indicated treatments after 72 hours (n = 3). Means ± SEM are presented. Statistical analysis was performed using the 2-way ANOVA with the Tukey comparison. ns, P > .05; ∗P < .05; ∗∗∗P < .001. E:T, effector-to-target ratio; ns, not significant; WT, wild-type.