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Fig. 5 | BMC Cancer

Fig. 5

From: Palmitate-induced ER stress increases trastuzumab sensitivity in HER2/neu-positive breast cancer cells

Fig. 5

Exogenous palmitate increases DDIT3/CHOP expression in HER2/neu positive breast cancer cells. a MCF7 and SKBR3 cells were treated with 250 μM palmitate or vehicle control for 24 h. C16 = palmitate. Total protein was harvested and subjected to western blot analysis to evaluate the protein expression changes for the ER stress related markers PERK, phospho-PERK (pPERK, Thr980), PDI, BiP, eIF2α, phospho-eIF2α (p-eiF2α, Ser51) and DDIT3/CHOP. Each experiment was performed in triplicate, representative images are shown. b Quantification of the DDIT3/CHOP western blots using ImageJ. c Cells were treated with vehicle for 24 h and assessed for basal levels of DDIT3, normalized to MCF7 levels. Quantification of DDIT3 mRNA levels after treatment with 500 μM sodium palmitate for 24 h. The data are presented as mean ± SEM of three independent experiments. d SKBR3 cells were transfected with an shRNA targeting DDIT3/CHOP or luciferase, which has no target in these cells. 48 h post-transfection the cells were treated with 250 μM palmitate or vehicle for 24 h and nuclei were counted using the INCell Analyzer 2200. e MCF7 and SKBR3 cells were treated with 250 μM palmitate or vehicle either alone or in the presence of the chemical chaperone 4-PBA for 24 h. Nuclei were counted and the data were normalized to control conditions. Data are presented as mean ≤ SD. * = p ≤ 0.05, ** = p ≤ 0.01, *** = p ≤ 0.001. One-way ANOVA with Bonferroni post-test. n = 3

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