Fig. 1.

The knocking down of CD44 markedly suppresses the proliferation and invasion of mesenchymal TNBC cell lines. a–c The efficiency of shRNA vectors in knocking down CD44 was determined in stable cell lines at the protein level. d–f MTT assay was performed in stable cell lines to determine the effect of CD44 knockdown on cell proliferation. The OD490 value was read at three indicated time points and the values were normalized to that of day 3. The results are shown as mean ± SEM. ****P < 0.0001; this experiment was independently performed 3 times. g, h Colony formation assay was performed to assess the effect of CD44 knockdown on colony formation ability. i, j Transwell assay was carried out to decipher the impact of CD44 knockdown on invasion. A representative picture of three independent experiments is shown for each cell line and the related statistic results are shown as mean ± SEM. **P < 0.01; ***P < 0.001; this experiment was independently performed 3 times. Scale: The black rectangular box at the right bottom corners of figure i represents the 100 µm scale. k, l Western blotting was carried out in SUM159 cells with CD44 stably interfered with 29-mer shRNA and miR-N shRNA, respectively. TNBC triple-negative breast cancer, shRNA short hairpin RNA, MTT assay 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, OD490 optical density at 490 nm, SEM standard error of the mean, NT non-targeting, GAPDH glyceraldehyde-3-phosphate dehydrogenase