Figure 2.

Characterization of the HER2⁺/CD44⁺/CD24^−/low BCSCs within MCF7/C6 cell lines. (A) CD44⁺/CD24^−/low cells were sorted from 2.5 × 10⁷ MCF/C6 cells with CD44 and CD24 antibodies (left panel), from which the cells were further sorted with HER2 antibody (right panel). The orange box in the left panel indicates the CD44⁺/CD24^−/low fraction used for sorting HER2⁺/CD44⁺/CD24^−/low (yellow box), HER2⁻/CD44⁺/CD24^−/low cells (red box) and a global HER2⁻/CD44⁺/CD24^−/low population (blue box with a broader gate). (B) Percentages of CD44⁺/CD24^−/low and HER2⁺/CD44⁺/CD24^−/low cells derived from MCF7/C6 cells (left panel, also shown in Table S2). Western blot analysis of HER2 and CD44 protein expression in sorted HER2⁺/CD44⁺/CD24^−/low and HER2⁻/CD44⁺/CD24^−/low cells (right panel). (C) Analysis of ALDH activity in HER2⁻/CD44⁺/CD24^−/low versus HER2⁺/CD44⁺/CD24^−/low cells via flow cytometry using Aldefluor staining. As negative control, cells were incubated with ALDH inhibitor DEAB. (D) Quantification of the ALDH expression HER2⁺/CD44⁺/CD24^−/low compared to HER2⁻/CD44⁺/CD24^−/low BCSCs analysis in C.