B). JAK inhibitor baricitinib blocked activation of STAT3 by LIF. BAE cells pre-incubated with DMSO and inhibitors for 1 hour were treated with vehicle and LIF (10 ng/ml) for 15 minutes. Whole-cell lysates were subjected to Western blotting with indicated antibodies. Ctrl, no pre-incubation with inhibitors; Ba, baricitinib (2 μM); Co, cobimetinib (150 nM); BE, BEZ235 (5 nM). 