Fig. 2
Co-injected miPSCs acquired CSC features. A Representative images of mice and isolated tumors resulted from the injection of cells in Fig. 1D. The miBx, miPa, and miPk cells were injected at dose of 5 × 105 cells/mouse and the mice were sacrificed after 4 weeks. Mice injected with miPSCs were used as controls. B A bar graph shows the volume of each tumor in A. n = 3 for each condition. *, p < 0.05. C Representative images of the primary cultures from tumors formed in the pancreases by miBx, miPa, miPk cells, and miPSCs. Cells were GFP positive forming colonies while those from miPSC tumors were GFP negative. Scale bars = 100 μm. D Photographs of the cells in C after treatment with 1.5 μg/ml puromycin for 1 week. Scale bars = 100 μm. E The summary of tumors formed in the pancreases by miBx, miPa, and miPk cells. Groups of three mice were injected with either 5 × 103, 5 × 104 or 5 × 105 of miBx, miPa or miPk cells/mouse. Mice were sacrificed 4 weeks after injection of 5 × 105 and 5 weeks after injection of 5 × 103 or 5 × 104 cells. F Representative images of tumors resulted from the injection of 5 × 103 of miBx, miPa and miPk cells. G The histological evaluation of tumors by H&E staining. The tumor sections of miBx (a), miPa (b), and miPk cells (c) showing malignant phenotypes with mitotic figures, nuclear atypia, and high nuclear to cytoplasmic ratio. d ~ g Sections of miPSCs tumors showing (d) normal pancreatic tissue (Pa) and tumor tissue from the injection of miPSCs (T). The miPSC tumor sections displayed endoderm-derived glands (e), ectoderm-derived neuroepithelial tissues (f), and mesoderm-derived muscle tissues (g). H The metastases after injection of cells in the pancreases (left column) and primary cells isolated from the metastases (middle and right columns). Metastasis of miBx cells on the diaphragm (a) and the mesentery (b), metastasis of miPk cells on the diaphragm (c), and metastasis of miPa cells on the diaphragm (d). The bright field (middle column), the fluorescence of GFP (left column). I Immunostaining of the tumor sections with anti-GFP Ab, anti-Ki67 Ab, and anti-CD44 Ab. Scale bars = 64 μm. J Histogram of the area immunoreactive to anti-GFP Ab, anti-Ki67 Ab and anti-CD44 Ab. All data were obtained from three independent tumors (n = 3), statistically analyzed and presented as mean ± SD. **, p < 0.001; ***, p < 0.0001