Whole-cell lysates of ≥100,000 cells were used per lane. Western blotting was performed as previously reported [2 (link)]. Briefly, cells were rinsed with cold PBS and scraped into RIPA buffer supplemented with protease inhibitors, sonicated twice, and re-suspended in 4X sample buffer (BioRad; Hercules, CA) supplemented with 10% beta-mercaptoethanol (Sigma-Aldrich; St. Louis MO). The Pierce BCA protein assay kit (Thermo Fisher Scientific; Grand Island, NY) was used to determine protein concentration. Protein (60 μg) was electrophoresed on 10% SDS-polyacrylamide gels and transferred to nitrocellulose (Odyssey, LI-COR Biosciences; Lincoln, NE) overnight at 4°C. Membranes were blocked overnight in 5% non-fat milk in TBS at 4°C. Primary antibodies used were: anti-SOX2 (D6D9 rabbit monoclonal, Cell Signaling Technologies) and anti-beta actin (clone AC-15, Sigma-Aldrich). Secondary antibodies were goat anti-mouse IRDye 800 CW or donkey anti-rabbit IRDye 680 (LI-COR Biosciences), and images were captured using an infrared Odyssey scanner (LI-COR Biosciences).