Fig. 3

Removal of residual USCs using YM155. Cytotoxicity was measured by WST after QIA7, WA01, QIA7-iHeps and hAT-SCs were treated with YM155 (0–10,000 nM) for 24 h (a). With the selected concentrations (from 1 to 100 nM), cell viability was estimated at stage I of QIA7 (day 4) and stage II (day 6) (b). Expression of apoptosis-related genes (BIRC5, BCL-2 and BAX) was measured after 24 h of YM155 treatment at stage II (c). To further evaluate YM155-induced apoptotic cell death, Caspase-3 activity was estimated after 16-h incubation with YM155 in QIA7, QIA7-iHeps and hAT-SCs (d). YM155 removed the cell clusters (arrow) in a concentration-dependent manner (e). The decrease of USCs was confirmed by flow cytometer using OCT4 antibody (f). Pluripotent genes (NANOG and OCT4) were decreased by YM155, but endodermal genes (CXCR4, SOX17 and FOXA2) were increased in a dose-dependent manner (g).*p < 0.05 (significantly different from the control). BAX bcl-2-like protein 4, BCL-2 B-cell lymphoma 2, BIRC5 baculoviral inhibitor of apoptosis repeat-containing 5, CXCR4 C-X-C chemokine receptor type 4, DMSO dimethyl sulfoxide, FOXA2 forkhead box protein A2, hAT-SC human adipose tissue-derived stromal cell, iHep induced hepatocyte, OCT4 octamer-binding transcription factor, SOX17 sex determining region Y-Box 17