Figure 4.

Impact of the Trk inhibitor GNF-5837 on HER2-positive breast cancer cell lines. HER2-positive breast cancer cells were treated with 0–40 µM grade concentrations of the Trk inhibitor GNF-5837, with and without 50 µg/mL Herceptin, in media containing 10% FBS for 48 h and a dose–response curve and associated IC₅₀ values were generated for (A) SK-BR-3, (B) BT-474, (C) MDA-MB-453 and (D) JIMT-1. Data are presented as the mean ± SD of samples from three independent experiments. (E) Effect of 0–20 µM GNF-5837 on TrkA phosphorylation and downstream cellular signaling. Western blot analysis was performed 48 h post-treatment with GNF-5837. The level of phospho-TrkA (p-TrkA) and phospho-AKT (p-AKT, Ser473) both decreased in a dose-dependent manner in all HER2-positive breast cancer cell lines. The 0.1% DMSO was used as the negative control treatment for the viability assay and β-actin protein expression was used as an equal loading control in Western blotting.