Characterization of the isolated EpSCs. The morphology of the isolated cells are bird nest-like or slabstone-like (A). The isolated cells positively express CD34 (B) and β1 integrin (C) as detected by immunofluorescence. (D) EpSCs treated with 10-7 M for 12 days showed polygonal or long spindle morphology. (E) CK18 expression in these SP-induced EpSCs indicated these cells were differentiated, as demonstrated by immunocytochemistry. (F) Wnt agonist triggers EpSC differentiation, as demonstrated by CK18 immunocytochemistry. (G) CD34 positive expression in the SP with Dkk-1 treated EpSCs demonstrated that these cells were still stem cells, as detected by immunofluorescence. (H) Fluorescence microscopy image of the transduced EpSCs. (I) The transduced EpSCs did not undergo differentiation upon SP treatment. Scale bar =20 μm.