Fig. 4: Pterostilbene (PT) induces endoplasmic reticulum (ER) stress in hepatocellular carcinoma (HCC) cells.

Huh-7 and SK-Hep-1 cells were treated with various concentrations of PT for 24 h and then stained with ER-ID Red. a Morphological changes of ER were observed under a fluorescence microscope. b The intensity of fluorescence was quantified using a flow cytometer. c Western blotting was performed to investigate the expression levels of ER stress-related proteins. d Huh-7 cells were pretreated with or without 4-bisphenol A (4-BPA) (1 mM) for 2 h, followed by a treatment with PT (100 μM) for 24 h. The ER intensity of fluorescence was quantified using a flow cytometer. e Expression levels of Bip, activating transcription factor (ATF4) and LC3-II were determined through Western blotting analysis. β-Actin was employed as an internal control. Data are presented as mean ± standard error for three experiments. **p < 0.01 compared with controls. #p < 0.01 compared with PT treatment alone