STAT1-mediated IFNγ signaling and IDO1 expression in BC cells. A and B, Immunoblot analysis of IFNγ-treated MDA-MB-231 and MCF7 cell lysates in time-course experiments and probing for indicated proteins. C, JAK inhibitor ruxolitinib effectively blocked IFNγ-induced STAT1-mediated IDO1 and IRF1 protein expression in MDA-MB-231 cells. D, Densitometric analysis of pSTAT1 bands. E, Knockdown of STAT1 with two different siRNAs effectively blocked IFNγ-mediated IDO1 protein expression. Results in A and B are blots from a single time course experiment. Results in C, D and E are representative of at least two independent experiments.