(A) A model showing whether the potentiation effect of MMAE is dependent on the direct STING-IRF3 signal axis or the indirect IFNα/β and its receptors (IFNAR) pathway. (B-I) ISRE reporter activities and STING phosphorylation cascades were measured in response to cGAMP, RO8191 (0.25 μM, an IFNAR2 agonist) or combined with indicated MMAE for 24 h or 6 h in THP1-Lucia ISG cells (WT, STAT1 KO, STAT2 KO and STAT3 KO). The fold changes in luminescent signals were normalized to DMSO-treated cells. The activation of STING signaling was assessed by immunoblotting. Data are representative of three independent experiments. Bars are the mean ± SEM of indicated (n) independent experiments. Significance was determined by one-way ANOVA; *p p p p (TIF)</p