A novel monomer of Elephantopus mollis H.B.K., EM-6, inhibits the proliferation of Huh-7 cells by blocking autophagic flux and activating the ROS/MAPK pathway

Abstract

Abstract Purpose Primary liver disease is one of the major health problems in the world, and the prognosis of liver cancer is very poor. Liver cancer cells develop strong resistance to clinical chemotherapy drugs, leading to repeated liver cancer. Materials and Methods RNA-sequence was applied to related signal pathways that significantly altered. Flow cytometry and Western blot were performed to detect the changes of cell cycle, apoptosis and MAPK pathways. Immunofluorescence and flow cytometry were used to detect changes in cell mitochondrial membrane potential and intracellular ROS levels. Western blot, immunofluorescence, qRT-PCR and mCherry-GFP-LC3 were used to detect the effect of autophagy. Western blot and qRT-PCR were utilized to detect the effect of ER Stress. Results EM-6 is a novel monomer purified from Elephantopus mollis H.B.K. Mechanistically, compared with cisplatin (CDDP), EM-6 significantly inhibited the proliferation of human hepatocellular cancer cell lines and had less toxicity to human normal epithelial cells. EM-6 can induce mitochondrial membrane potential disruption, which leads to the accumulation of ROS, S-phase arrest and activation of the IRE1α-ASK1-JNK/p38 pathway to promote apoptosis in Huh-7 cells. In addition, EM-6 blocked protective autophagy by inhibiting the initiation of autophagy, and inhibiting the formation of autophagolysosomes triggered Huh-7 cell apoptosis. Conclusion Taken together, our findings suggest that EM-6 activates mitochondrial apoptosis through the ROS/MAPK pathway and promotes the activation of ER stress and the inhibition of autophagic flux to exacerbate apoptosis. These studies demonstrated the promising future of EM-6 in the clinical treatment of hepatocellular cancer.