Figure 6.

Administration of NRG4 boosts the anti-cancer efficacy of anti-HER2 agents in SKBR3 HER2+ breast cancer cells. (A–H) Time-lapse analysis over time by Livecyte technology. SKBR3 cells were cultured in vitro and treated with/without NRG4 (10 ng/mL), alone or in combination with trastuzumab (10 µg/mL) or pertuzumab (10 µg/mL) and monitored up to 72 hours. Representative images are provided at 72 hours post-treatment; scale bar 75µm; Cell growth over time, normalized to cell number at 0 hours, is provided in (B); cell growth and cell doubling time during the first day (0-24 hours), second day (24-48 hours), and third day (48-72 hours) are provided in (C–H) respectively; (I) Western blot analysis of phosphorylated (active) and total ERBB4 protein levels in lysates of SKBR3 cells cultured in vitro and treated with/without NRG4 (10 ng/mL), alone or in combination with trastuzumab (10 µg/mL) or pertuzumab (10 µg/mL) for 30 minutes. In all panels, numerical data are presented as mean (error bars show s.e.m.); statistical significance was determined using two-way ANOVA in (B) and one-way ANOVA in (C–H), followed by Tukey’s test; (*) p < 0.05, (**, ^^, &&) p < 0.01, (***, °°°, $$$, £££, @@@) p < 0.001, (****, ^^^^, °°°°) p < 0.0001.