Fig. 2
Sustained MYC overexpression confers stem cell-like traits. a Phase contrast images of IMEC WT and IMEC-MYC cultured in low adhesion conditions. Scale bar, 100 µm. b Spheres formation efficiency (SFE) of IMEC WT and IMEC-MYC at indicated passages (n = 6) (**P < 0.01, ***P < 0.001; Student’s t-test). c Area (μm2) of mammospheres formed by IMEC WT and IMEC-MYC at indicated passages (n = 6). Whiskers extend to 10th and 90th percentiles; central horizontal bar and black cross indicate median and mean, respectively (*P < 0.05, **P < 0.01, ***P < 0.001; Student’s t-test). d Percentage of ALDH1-positive cells in IMEC WT and IMEC-MYC cultured in low adhesion conditions. Data are means ± SEM (n = 3) (**P < 0.01; Student’s t-test). e Single cell SFE of IMEC WT, -MYC, -PIK3CAH1047R, -P53DD and -RAS. Data are means ± SEM (n = 3) (*P < 0.05; Student’s t-test). f Serial single-cell SFE of IMEC-MYC, IMEC-MYC-derived 1° Spheres (M1) and IMEC-MYC-derived 2° Spheres (M2). Single-cell-derived clones were obtained at the indicated time. Data are means ± SEM (n = 4) (**P < 0.01, ***P < 0.001; Student’s t-test). g Immunofluorescence for basal (CK14 and α-SMA) and luminal (CK8 and ER-α) markers on differentiated M2. Scale bar, 50 µm. h Scatter-plot of gene expression profile of IMEC-MYC and M2. Genes up- (cyano) and downregulated (blue) in M2 with respect to IMEC-MYC are highlighted. Relevant M2 upregulated genes are indicated (n = 3). i GO analysis of differentially regulated genes between IMEC-MYC and M2 (n = 3). j GSEA of the core embryonic stem cell (ESCs) gene module in IMEC-MYC vs. M2 (n = 3). k Scheme representing IMEC-MYC and IMEC-MYC-derived mammospheres, enriched for cells with self-renewing capacity
