Arsenic trioxide-induced apoptosis of Hep-2 cell line through modulating intracellular glutathione (GSH) level

Background: Since 1970s, a Chinese study group at Harbin Medical University First Hospital discovered the anticancer effect of arsenic trioxide (As(2)O(3)), it has become evident that apoptotic effects of As(2)O(3) are not restricted to APL cells but also can be observed in other malignant cells in vitro, including non-APL acute myeloid leukemia cells, myeloma cells, and chronic myeloid leukemia cells, as well as various solid-tumor cells, such as esophageal, prostate, and ovarian carcinomas and neuroblastoma cells. Objective: To investigated if As(2)O(3) could induce cell death and apoptosis of Hep-2 cells, a laryngeal squamous cell carcinoma (LSCC) cell line. Methods: Trypan blue exclusion assay, LDH release assay and cytometric method were used for the measurements of cell death and apoptosis. We measured intracellular GSH, ROS and mitochondrial membrane potential to explore the mechanisms of cell death and apoptosis induced by As(2)O(3) in Hep-2 cells. Results: Trypan-blue-positive cells and the release of LDH into medium induced by As(2)O(3) increased in a dose- and time-dependent manner. The rates of apoptosis increased induced by As(2)O(3) in a dose- and time-dependent manner. In order to elucidate the mechanisms of cell death and apoptosis induced by As(2)O(3) in Hep-2 cells through GSH, we found that As(2)O(3) induced the decrease of intracellular GSH, increase of ROS and loss of mitochondrial membrane potential. And pretreatment of BSO, an inhibitor of GSH biosynthesis, depleted partly intracellular GSH and increased trypan-blue-positive cells, the release of LDH, apoptosis, ROS and loss of mitochondrial membrane potential. However, pretreatment of GSH had resistance to the changes to some extent as described above. Conclusion: As(2)O(3)-induced apoptosis of Hep-2 cell line through modulating intracellular GSH level. (C) 2009 Published by Elsevier Ireland Ltd.