(MilliporeSigma) with proteinase inhibitor cocktail, cOmplete mini EDTA-Free (Roche). The
Pierce BCA Protein Assay Kit (Thermo Fisher Scientific) was used for measuring the protein
concentration of lysates. Samples were subjected to SDS-PAGE and transferred to PVDF
membranes (GE Healthcare). Tris-buffered saline (TBS) buffer containing 5% bovine
albumin fraction V (MP Biomedicals) and 0.1% Tween-20 (Sigma-Aldrich) was used for
blocking. Stripping of membrane was performed using Restore Western Blot Stripping Buffer
(Thermo Fisher Scientific). Antibodies used were those against AKT (#9272, Cell
Signaling Technology), phospho-p44/p42 MAPK (ERK1/2) (Thr202/Thy204) (#9101, Cell
Signaling Technology), ERK1+ERK2 (ab17942, Abcam), PAX8 (clone PAX8R1, ab53490, Abcam),
E-cadherin (clone 24E10, Cell Signaling Technology), α-tubulin (clone DM1A,
sc-32293, Santa Cruz), and β-actin (clone D6A8, #8457, Cell Signaling
Technology). Anti-NKX2-1 and anti-phospho-AKT (Ser473) antibodies were the same as those
used for immunohistochemistry/immunofluorescence.