Anti-NEK2 antibodies (610593) for used in western blot analysis and immunofluorescence microscopywere purchased from BD Biosciences (San Jose, CA, USA) and those (sc-55601) for performing NEK2 kinase assay were purchased from Santa Cruz Biotechnology (Santa Cruz, CA, USA). Anti-ALDH1 antibodies (611194) were acquired from BD Biosciences. Antibodies against Smad2/3 (#5678), phosphorylated Smad2 (#3108), β-catenin (#9562), and phosphorylated β-catenin (Ser33/Ser37/Thr41, Ser45, or Ser675; #9561, #9564, or #4176, respectively) were purchased from Cell Signaling Biotechnology (Danvers, MA, USA). Antibodies against E-cadherin (ab15148), N-cadherin (ab18203), vimentin, Snail (ab180714), Twist (ab175430), Bmi1 (ab126783), Sox2 (ab97959), octamer-binding transcription factor 4 (Oct4; ab109183), Kruppel-like factor 4 (Klf4; ab129473) and Nanog (ab109250) were obtained from Abcam (Cambridge, MA, USA). Anti-β-actin antibody (sc-4778) and anti-Sp1 antibody (sc-17824) were obtained from Santa Cruz Biotechnology, and wortmannin, MG132, H89, PP2 and bisindolylmaleimide I (BMI) were purchased from Calbiochem (San Diego, CA, USA). Wnt3a was purchased from R&D Systems Inc. (Minneapolis, MN, USA). CGK062 was prepared as previously described (23 (link)).