PRIMA-1MET/APR-246 (2,2-Bishydroxymethyl-1-aza-bicyclo[2.2.2]octan-3-one) was obtained from Sigma-Aldrich Corp. (St. Louis, MO, USA). Dulbecco's modified Eagle's medium (DMEM), Ham's/F12 medium, HEPES buffer, fetal bovine serum (FBS), amphotericin B, mouse epidermal growth factor (EGF), TRIzoland Alexa Fluor 488 goat anti-mouse, goat IgGs were from Life Technologies (Carlsbad, CA, USA). Hydrocortisone, dimethyl sulfoxide, cholera toxin, 0.3% hydrogen peroxide, insulin-transferrin-sodium selenite media supplement, acetone, Triton X-100, bovine serum albumin (BSA), and FITC-conjugated anti-rabbit IgG were from Sigma-Aldrich Corp. Mouse anti-cytokeratin 10 (K10), cytokeratin 14 (K14), cytokeratin 19 (K19) antibodies, and diaminobenzidine (DAB) were from Dako Cytomation (Carpinteria, CA, USA). Mouse anti-Pax6 and β-catenin antibodies were from Santa Cruz Biotechnology (Santa Cruz, CA, USA). Mouse monoclonal anti-MUC5AC antibody and rabbit anti-p63 antibody were from Abcam (Cambridge, MA, USA). Immunofluorescence mounting medium with DAPI (4,6-diamino-2-phenyl indole) was from Vector Laboratories (Burlingame, CA, USA). Six-well and 12-well plate inserts were from Merck Millipore (Bedford, MA, USA). Plastic cell culture dishes were from BD Biosciences (Lincoln Park, NJ, USA).