title: In vitrostimulation of calcium overload and apoptosis by sonodynamic therapy combined with hematoporphyrin monomethyl ether in C6 glioma cells.
abstract: The present study investigated enhancement of apoptosis induction and the mechanisms underlying calcium overload on C6 glioma cellsin vitro,stimulated by low-level ultrasound in combination with hematoporphyrin monomethyl ether (HMME). The optimum frequency of ultrasound was determined by 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The apoptotic rate, reactive oxygen species concentration and decreased mitochondrial membrane potential (MMP) were analyzed by flow cytometry. Morphological changes were detected by a transmission electron microscope, and the concentration of intracellular Ca2+, [Ca2+]i, was detected by a confocal laser scanning microscope. In addition, the release of cytochromec(cyt-c) was measured by western blot analysis. The results revealed that an increased apoptotic effect was induced by sonodynamic therapy (SDT), and this was found to correlate with the overloaded [Ca2+]i, derived from the intra- and extracellular sources in the early apoptotic process. The results also revealed an increased level of ROS production, a decreased MMP and an increased release of cyt-c. The present study indicated that low-level ultrasound in combination with HMME improved the apoptotic effect in C6 glioma cells. The overloaded [Ca2+]iwas involved in the mechanism by which apoptosis was stimulated and enhanced by SDT.
authors.affiliation: Department of Ultrasound, The Third Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Shaochun
authors.initials: S
authors.lastname: Dai
authors.affiliation: Department of Pathophysiology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Changqing
authors.initials: C
authors.lastname: Xu
authors.affiliation: Department of Pathophysiology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Department of Ultrasound, The Third Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Wen
authors.initials: W
authors.lastname: Cheng
authors.affiliation: Department of Ultrasound, The Third Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Bo
authors.initials: B
authors.lastname: Li
keywords: C6 glioma cells; apoptosis; calcium overload; reactive oxygen species; sonodynamic therapy