(A) Western Blot analysis on ESCs treated with either RA or RA with 5.0 μM LY294002 for 12h. NANOG was considered the positive control for treatment evaluation. (B) The mRNA expression levels were assessed by qRT-PCR and normalized to RM condition. The average and SD of duplicate samples from each of three independent biological replicates are shown: **, p < .01; ***, p < .001, in a Student’s t test. (C) Western Blot analysis on ESCs were treated with either RA or RA with 20 μM PD0325901 for 12h. ESCs treatment with RA increased pERK1/ERK2, whereas PD treatment hampered pERK1/ERK2. (D) The mRNA expression levels are assessed by qRT-PCR and normalized to RM condition. The average and SD of duplicate samples from each of three independent biological replicates are shown: *, p < .05, in a Student’s t test.