Effects of MEKi and STAT3i on cancer stem cells (CSCs) in PKT mice. Single cell suspension isolated from pancreatic tumors of PKT mice treated with AZD1480, AZD6244 or AZD1480/AZD6244 were analyzed for CSC population by flow cytometry. A, CD44+ tumor cell populations (CD45NegEpCam+CD44+) were significantly decreased in the combined MEKi/STAT3i treatment compared to STAT3i alone or the vehicle groups. B, CD133+ tumor cell populations (CD45NegEpCam+CD133+) were significantly decreased in the combination MEKi/STAT3i compared to the vehicle treated group. *, P < 0.05; **, P < 0.01; ns, P > 0.05.