Fig. 5.

The eIF2α-phosphatase inhibitor SAL003 potentiates Trastuzumab’s anti-proliferative effects. a Immunoblot analyses of protein extracts from sensitive (S) or resistant (R) to Trastuzumab BT474 cells treated with 21 µg/ml Trastuzumab, 10 µM SAL003 or both for 3 h. Graphs represent the quantification of data from 3 biological replicates and are shown as mean + SEM *p < 0.05; **p < 0.01; ***p < 0.001. b, c Evaluation of the colony forming efficacy of Trastuzumab-sensitive (S) or resistant (R) BT474 cells (b), as well as of Trastuzumab-resistant HER2+ breast cancer BM-132 cells (c) after treatment with 0.02% v/v DMSO (CON), 21 µg/ml Trastuzumab (TZ), 5 µM SAL003 or both drugs at the same concentrations as the single treatments (TZ + SAL). The graphs show the % inhibition of the colony forming efficacy of the cells after normalization to CON cells. The data were obtained from 3 biological replicates and are shown as mean ± SEM *p < 0.05; **p < 0.01; ***p < 0.001