Two Novel Curcumin Analogues Induced Reactive Oxygen Species Generation and Mitochondrial-Related Apoptosis in Human Breast Cancer MCF - 7 Cells

Abstract

Objective: Curcumin has been shown to have significant protective effects against cancer and induction of apoptosis is a crucial strategy for cancer therapy, so we have now evaluated the mechanisms involved in two novel asymmetric curcumin analogues induced cell death in MCF - 7 cells. Methods: The cytotoxicity of two curcumin analogues towards tumor cells was investigated by MTT assays. The morphological analysis using a laser scanning confocal microscope. Futher cell cycle analysis, reactive oxygen species (ROS), mitochondrial transmembrane potentials (Δφm), intracellular Ca2+ levels analysis and apoptosis assays via a flow cytometry (FCM). We used western blot assays to determine the expressions of apoptosis-related factors and p38MAPK at protein level. Results: MCF - 7 cells showed a significant loss of viability, reduced mitochondrial membrane potential (Δφm), increased intracellular Ca2+ levels, and increased production of ROS, which activated the pro-apoptotic p38 mitogen-activated protein kinase. Pretreatment with the antioxidant, N-acetylcysteine, inhibited both two curcumin analogues mediated ROS production and cytotoxicity. Western blotting revealed that the loss of Δφm inhibited Bcl-2, and induced Bax and Bak expression; this promoted release of cytochrome c and apoptosis inducing factor from the mitochondria to the cytosol, activation of caspase-9 and caspase-3 in the cytosol, and induction of apoptosis. Conclusion: The two curcumin analogues displays strong antitumor effect through ROS-dependent mitochondria apoptosis pathway in MCF - 7 cells, and has promising potential to be developed as antitumor compounds.