Investigation of cytotoxic, genotoxic, and apoptotic effects of curcumin on glioma cells

Abstract

Glioblastoma is a malignant tumor of the brain. The treatment of this tumor is still a challenge. Curcumin has been shown to have therapeutic effectswhen used to treat malignant diseases. However, the molecular mechanisms of its action are not fully elucidated. We hypothesized that reactive oxygen species(ROS) have a key role in curcumin-induced DNA damage, apoptosis, and cell death. To test our hypothesis, cytotoxic, genotoxic, apoptotic, and ROS-generatingeffects, as well as mitochondrial membrane potentials of curcumin on rat glioma cells (C-6) and normal fbroblastic cells (L-929) were investigated. We examinedconcentration-dependent cytotoxic, genotoxic, apoptotic, and ROS generating effects of curcumin at C-6 cells and L-929 cells. The cells were incubated withdifferent doses of curcumin (10-100 μ M) for 24 hours. Higher doses of curcumin resulted in greater cellular death of cancer than of normal cells at higher concentrations. Curcumin also induced ROS generation in cancer than normal cells in a concentration-dependent manner. Our results showed that curcumin-induced DNAdamage in a dose-dependent manner (p < 0.001). At high curcumin concentration such as 80 μ M, the proportions of live cells in cancer and normal cell lines were11.5 and 44.3, respectively. The higher doses of curcumin resulted in greater apoptosis in cancer than normal cells.This in vitro study provided clear evidence thatcurcumin induced DNA damage and apoptosis. Cytotoxicity may be due to its pro-oxidant activity in a dose-dependent manner in cancer and normal cells. Theseactivities were higher in cancer cells.