Fig. 5: SNAI1 knockout drives the generation of a population enriched in epithelial stem-like/progenitor cells with increased mammosphere-forming ability.
From: Loss of SNAI1 induces cellular plasticity in invasive triple-negative breast cancer cells
A Representative immunofluorescence staining pictures from three independent biological repeats of F-actin (green) and cleaved caspase 3 (red) in mammospheres derived from MDA-MB-231-WT, SNAI1-KOs, ZR-75-1 and CS16 SNAI1-GFP#7 cells. Nuclei are stained in blue with DAPI. Scale bars = 50 μm. B Bar graph showing the biological processes relevant to breast morphogenesis enriched in SNAI1-KOs. The horizontal axis indicates the number of genes annotated to each process and the color code represents the corresponding p-value. C ELDA depicting the stem cell frequency of MDA-MB-231-WT (green curve), SNAI1-KO CS16 (black curve), CS19 (red curve), ZR-75-1 (blue curve) and CS16 SNAI1-GFP#7 (turquoise curve) cells cultured for 10 days. The number of wells containing spheres for each plating density is plotted. Steeper slopes indicate higher frequencies of sphere-forming cells. The table indicates the average stem cell frequency per cell group of three independent biological replicates. D Representative phase contrast images from three biological repeats showing MDA-MB-231-WT, SNAI1-KO, ZR-75-1 and CS16 SNAI1-GFP#7 mammospheres from the experiment in C. Scale bars = 100 μm. E–G Heatmaps demonstrating expression levels of differentially expressed genes involved in stem cell-related biological processes based on gene set enrichment analysis. The color-coded scales represent normalized counts per million values of WT and SNAI1-KO cells. H RT-qPCR analysis of KIT, ALDH1A1, SOX2, SOX9 and CD44 mRNA levels in ZR-75-1, MCF-7, MDA-MB-231-WT, and SNAI1-KO cells. Values represent fold-change of mRNA expression normalized to GAPDH and expressed relative to the level in MDA-MB-231 cells. Data are presented as mean values of three biological replicates ± SEM, each in technical triplicates and p-values are shown based on two-tailed unpaired Student’s t-test. p-values *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001.
