Fig. 1

Assessment of HER2 expression in a series of breast cell lines. (A) List of the cell lines employed in this study (B) Western blot analysis of HER2 expression on extracts from MDA-MB-231, MDA-MB-468, MCF7, BT474 and SKBR3 cells derived from different BCs; MCF10A cells, derived from non-tumorigenic breast epithelium, were used for comparison. α-Tubulin was used to normalise the amounts of proteins loaded in each lane. The histogram reports HER2 total expression as Relative Units (R.U.) compared to MCF10A cells. Statistical significance is considered when **** p < 0.0001 (ANOVA). (C) Western blot analysis of the soluble form of HER2 (sHER2) present in the concentrated media from the same cells as in B). The histogram shows the relative quantification, expressed as Relative Units (R.U.), after normalization to protein loading through Ponceau S staining of the filter. Statistical significance is considered when **** p < 0.0001 (ANOVA). (D) Flow cytometry analysis of HER2 cell surface exposure in the same cell lines as in A). The percentages of cell counts are reported on the y axis, while the Fluorescence Intensity on the x axis. The plots also report the positions of the isotypes as black lines. The histogram shows the relative quantification, expressed as Mean Fluorescence Intensity (MFI). Statistical significance is considered when **** p < 0.0001 (ANOVA)