Combination Treatment with Arsenic Trioxide and Sulindac Induces Apoptosis of NCI-H157 Human Lung Carcinoma Cells via ROS Generation with Mitochondrial Dysfunction

Kim, Hak Ryul; Yang, Sei Hoon; Jeong, Eun Taik

Abstract

BACKGROUND: Arsenic trioxide (As2O3) has been used to treat acute promyelocytic leukemia, and it induces apoptosis in a variety of solid tumor cell lines including non-small cell lung cancer cells. However, nonsteroidal anti- inflammatory drugs (NSAID) can enhance tumor response to chemotherapeutic drugs or radiation. It was previously demonstrated that a combination treatment with As2O3 and sulindac induces the apoptosis of NCI-H157 human lung carcinoma cells by activating the caspase cascade. This study aimed to determine if a combination treatment augmented its apoptotic potential through other pathways except for the activation of the caspase cascade. MATERIAL AND METHODS: The NCI-H157 cells were treated with As2O3, sulindac and antioxidants such as glutathione (GSH) and N-acetylcysteine (NAC). The cell viability was measured by a MTT assay, and the level of intracellular hydrogen peroxide (H2O2) generation was monitored fluorimetrically using a scopoletin-horse radish peroxidase (HRP) assay. Western blotting and mitochondrial membrane potential transition analysis were performed in order to define the mechanical basis of apoptosis.
RESULTS
The viability of the cells was decreased by a combination treatment of As2O3 and sulindac, and the cells were protected using antioxidants in a dose-dependent manner. The increased H2O2 generation by the combination treatment was inhibited by antioxidants. The combination treatment induced changes in the mitochondrial tran-smembrane potential as well as the expression of the Bcl-2 family proteins, and increased cytochrome c release into the cytosol. However, the antioxidants inhibited the effects of the combination treatment.
CONCLUSION
Combination treatment with As2O3 and sulindac induces apoptosis in NCI-H157 human lung carcinoma cells via ROS generation with a mitochondrial dysfunction.