Fig. 1
Characteristics analysis of hUSCs. A Morphological images of hUSCs at different culture passages (scale bar = 100 μm and 50 μm). B The expressions of CD29, CD90, CD105, CD73, HLA-ABC, CD34, CD45, and HLA-DR and the co-stimulatory molecules CD80, CD86, and CD40 were examined by flow cytometry analysis. C The expressions of Nanog, Oct4, CD105, CD29, CD34, and CD133 were analyzed by RT-PCR analysis. D The expressions of the embryonic stem cell surface markers Oct4, SSEA-4, and Nanog in hUSCs were identified by immunofluorescence staining. E The hUSCs were differentiated into mature adipocytes and osteoblasts, with osteogenic or lipogenic differentiation media for the corresponding times. Osteoblasts and adipocytes differentiated by hUSCs were identified by staining with alizarin red and oil red O, respectively. F In vitro tumorigenicity of hUSCs was conducted in soft agar. Numerous colonies appeared in the soft agar in the 4T1 tumor cells (1 × 103/well) but not in the hUSCs, after an inoculation of 30 days. G, H In vivo tumorigenicity of hUSCs was performed in NOD-SCID mice with injection of 1 × 106 cells/100 μl. Visible tumor was observed in the 4T1 cell group at the breast pads in week 2 after inoculation, and the tumor presented in the image was at week 8 after inoculation, whereas there was no tumor formation in the hUSCs group after 20 weeks of inoculation