Delicaflavone induces ROS-mediated apoptosis and inhibits PI3K/AKT/mTOR and Ras/MEK/Erk signaling pathways in colorectal cancer cells

Colorectal cancer (CRC) is one of the most common malignant tumors worldwide and tends to have drug resistance. Delicaflavone (DLF), a novel anticancer agent of biflavonoid from Selaginella doederleinii Hieron, showed strong anti-CRC activities, which has not yet been reported. In this study, we investigated the effects and possible anti-CRC mechanism of DLF in vitro and in vivo. It was shown that DLF significantly inhibited the cells viability and induced G2/M phase arrest, apoptosis, the loss of mitochondrial membrane potential (Δψm), generation of ROS and increase of intracellular Ca2+ in HT29 and HCT116 cells by MTT assay, TEM, flow cytometry and inverted fluorescence microscope. Western blot and qPCR assays results further confirmed DLF induced caspase-dependent apoptosis and inhibited PI3K/AKT/mTOR and Ras/MEK/Erk signaling pathways in CRC cells. Meanwhile, DLF significantly suppressed the tumor growth via activation of Caspase-9 and Caspase-3 protein and decrease of ki67 and CD34 protein without apparent side effects in vivo. In summary, these results indicated DLF induced ROS-mediated cell cycle arrest and apoptosis through ER stress and mitochondrial pathway accompanying with the inhibition of PI3K/AKT/mTOR and Ras/MEK/Erk signaling cascade. Thus DLF could be a potential therapeutic agent for CRC.