Reactive oxygen species-mediated endoplasmic reticulum stress and mitochondrial dysfunction contribute to cirsimaritin-induced apoptosis in human gallbladder carcinoma GBC-SD cells

In this study, the anticancer effect of cirsimaritin, a natural flavonoid, against human gallbladder carcinoma cell line GBC-SD and the underlying mechanisms were investigated. Cirsimaritin inhibited the growth of tumor cells and induced mitochondrial apoptosis in GBC-SD cells. In addition, cirsimaritin triggered endoplasmic reticulum (ER) stress and down-regulated the phosphorylation of Akt, while knock-down of CHOP dramatically abrogated the inactivation of Akt and reversed the pro-apoptotic effect of cirsimaritin. Furthermore, cirsimaritin provoked the generation of reactive oxygen species in GBC-SD cells, while the antioxidant N-acetyl cysteine almost completely blocked the activation of ER stress and apoptosis, suggesting cirsimaritin-induced reactive oxygen species is an early event that triggers ER stress mitochondrial apoptotic pathways in GBC-SD cells.