Expression of interferon-β by eribulin in TNBC cell lines requires the DNA sensor cGAS. (A) Immunoblot analysis of cGAS, STING, and β-tubulin expression in THP-1 and TNBC cells. (B) IFNβ mRNA in TNBC cells transfected with 1 µg of HT-DNA for 24 hours or mock-transfected. (C and D) IFNβ mRNA in TNBC cells treated with 100 nM eribulin (ERB) for 2 hours (C) or 6 hours (D) as compared with DMSO controls. Significance was determined by two-way ANOVA (cell line * drug) with Tukey’s post hoc test. (E) IFIT1 mRNA in CAL-51 cells transfected with RFP-cGAS or mock-transfected and treated with DMSO (Veh) or 100 nM ERB for 24 hours. Significance was determined by two-way ANOVA (cGAS * drug) with Tukey’s post hoc test. (F) HCC1937 IFNβ intracellular protein in live cells treated with DMSO or 100 nM eribulin for 6 hours. Significance determined by an unpaired two-tailed t test. (G) Human IFIT1 mRNA in HCC1937 cells treated with 100 nM eribulin for 2, 6, or 24 hours compared with DMSO. Significance determined by vehicle-compared one-way ANOVA with Dunnett’s post hoc test. Data are shown as individual points from two independent biologic replicates with error bars denoting range. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. Veh, vehicle.