STING toxicity on lymphoma vs immunotherapeutic effect. (A) The Sting gene was knocked out of BL370 lymphoma cells using the CRISPR/cas9 system. Depicted is a western blot showing STING expression in BL3750 WT and STING KO clones, as well as splenocytes isolated from WT or STING KO mice. (B) Viability of WT and KO BL3750 cells after incubation with 20 µg/mL STINGa for 24 hours (n = 3). Statistical significance was calculated by a Student t test. Error bars are standard error of the mean (SEM). (C) STING knockout (KO) or wild-type (WT) BL3750 cells were implanted SC on STING KO or WT mice. Each mouse was implanted with 2 tumors, 1 on each side of the abdomen. At day 6, 8, and 10 after tumor implantation, 20 µg STINGa was injected into 1 tumor. Tumor growth of both the injected and distant tumors was monitored (5-10 mice per group). Statistical significance was calculated using 2 way analysis of variance (ANOVA). Error bars are SEM. ***P < .001. ns., not significant.