Fig. 9

Syndecan-1 is a modulator of EGFR expression and activation via Notch signaling in IBC. a Scatter plot shows a significant upregulation of EGFR mRNA in tissues of IBC (n = 13) vs non-IBC (n = 14). RQ values of EGFR mRNA expression in tissues of IBC vs non-IBC are log2-transformed and normalized to values of normal tissues collected during reduction mammoplasty. Bars represent median with interquartile range. * P < 0.05 as determined by Mann-Whitney U-test. b Pearson’s correlation between Syndecan-1 and EGFR mRNA expression in tissues of non-IBC tissues (left panel) and IBC (right panel). c EGFR mRNA and protein level expression in control and Syndecan-1-silenced SUM-149 and SKBR3 cells. ** P < 0.01 and ^# P < 0.001 as determined by Student’s t-test. d Expression of EGFR mRNA levels in control and Syndecan-1-silenced SUM-149 cells post GSI treatment. *P < 0.05 and ** P < 0.01 as determined by one-way ANOVA followed by Tukey’s multiple comparison test. e Colony formation post 10 ng/ml EGF treatment in control and Syndecan-1-silenced SUM-149 cells. ** P < 0.01 and ^# P < 0.001 as determined by one-way ANOVA followed by Tukey’s multiple comparison test. f Western blot analysis of the downstream signaling p-Akt^(Ser473) of EGFR signaling in response to EGF stimulation in control and Syndecan-1-silenced SUM-149 cells. Data represent mean ± SEM, n ≥ 3. Data shown are a single experiment representative of three independent experiments