Furazolidone induces apoptosis through activating reactive oxygen species-dependent mitochondrial signaling pathway and suppressing PI3K/Akt signaling pathway in HepG2 cells

Furazolidone (FZD), a synthetic nitrofuran with a broad spectrum of antimicrobial activities, has been shown to be genotoxic and potentially carcinogenic in several types of cells. However, the proper molecular mechanisms of FZD toxicity remain unclear. This study was aimed to explore the effect of FZD on apoptosis in HepG2 cells and uncover signaling pathway underlying the cytotoxicity of FZD. The results showed that FZD induced apoptosis in HepG2 cells in a dose-dependent manner characterized by nuclei morphology changes, cell membrane phosphatidylserine translocation, poly (ADP-ribose) polymerase (PARP) cleavage and a cascade activation of caspase-9 and -3. FZD could enhance reactive oxygen species (ROS) generation, up-regulate Bax/Bcl-2 ratio, disrupt mitochondrial membrane potential (MMP) and subsequently cause cytochrome c release. Both ROS scavenger (N-acetyl cysteine, NAC) and caspase inhibitors suppressed FZD-induced apoptosis. Furthermore, NAC attenuated FZD-induced ROS generation and mitochondrial dysfunction. Meanwhile, FZD treatment inhibited both the activation and expression of Akt, and PI3K/Akt inhibitor LY294002 promoted FZD-induced apoptosis. On the contrary, PI3K/Akt activator insulin-like growth factor-1 (IGF-1) attenuated lethality of FZD in HepG2 cells. In conclusion, it is first demonstrated that FZD-induced apoptosis in HepG2 cells might be mediated through ROS-dependent mitochondrial signaling pathway and involves PI3K/Akt signaling.