Hesperetin induces apoptosis of esophageal cancer cells via mitochondrial pathway mediated by the increased intracellular reactive oxygen species.

Esophageal cancer is of high prevalence and poor prognosis. Hesperetin has been reported to exert antitumor ability by inducing apoptosis in many cancers in vitro and in vivo without obvious toxicity. However, there is no study concerning about the effect of hesperetin on esophageal cancer. In this study, we aimed to investigate whether hesperetin could induce apoptosis in esophageal cancer cells and explore its potential mechanism. We found that hesperetin induced esophageal cancer cells apoptosis in a concentration-dependent and time-dependent manner compared with the untreated cells. Hoechst 33258 staining and flow cytometry analysis showed more apoptotic cells in the hesperetin-treated group (p < 0.05, respectively). The intracellular reactive oxygen species (ROS) increased significantly, and glutathione (GSH) was depleted. The loss of △Ψ m was more tremendous in the hesperetin-treated cells. N-acetylcysteine (NAC) reduced the proapoptotic ability of hesperetin, while DL-buthionine-S, R-sulfoximine (BSO) enhanced the anticancer effect. Western blotting showed that the expression levels of cytochrome C (Cyt C) and apoptosis-inducing factor (AIF) decreased in mitochondria and increased in cytoplasm (p < 0.05). The levels of intracellular cleaved caspase-9, cleaved caspase-3, Apaf-1, Bcl-2-associated X protein (Bax), and suppressor of fused (SuFu) increased, while B cell lymphoma 2 (Bcl-2) and Survivin decreased. What is more, in xenograft tumor model, hesperetin inhibited the tumor growth significantly via induction of cell apoptosis which was detected by TUNEL assay (p < 0.05). Taken together, our study demonstrated that hesperetin could induce cell apoptosis in esophageal cancer cells via mitochondrial-mediated intrinsic pathway by accumulation of ROS.