ABSTRACT
Acetaminophen (APAP) overdose is a major cause of drug-induced liver injury worldwide. Our current study was performed to assess the potential protective effects of γ-oryzanol (ORY) on APAP-induced liver injury in mice and explore the underlying molecular mechanisms. We unveiled that ORY alleviated the APAP-induced death of HL-7702 hepatocytes in vitro and liver injury in mice. Moreover, ORY promoted the nuclear translocation of Nrf2, increased the expressions of Nrf2-downstream antioxidative enzymes, including HO-1, NQO1, GCLC, and GCLM, and thereby restrained APAP-induced oxidative stress in hepatocytes. Moreover, ORY modulated the AMPK/GSK3ß axis that acts upstream of Nrf2 in hepatocytes. Compound C, an inhibitor of AMPK, prevented the ORY-mediated activation of Nrf2 and protection against APAP toxicity in HL-7702 hepatocytes. Additionally, in the liver of mice receiving APAP, ORY suppressed the nuclear translocation of the NF-κB p65 subunit, downregulated the expressions of iNOS and COX-2, and reduced the levels of pro-inflammatory factors including TNF-α, IL-1ß, IL-6, and NO. Taken together, our findings revealed that ORY is capable of ameliorating APAP-induced liver injury. The modulation of AMPK/GSK3ß/Nrf2 and NF-κB signaling pathways is implicated in the hepatoprotective activity of ORY.
Subject(s)
AMP-Activated Protein Kinases/metabolism , Acetaminophen/adverse effects , Chemical and Drug Induced Liver Injury, Chronic/drug therapy , Glycogen Synthase Kinase 3 beta/metabolism , NF-E2-Related Factor 2/metabolism , NF-kappa B/metabolism , Phenylpropionates/pharmacology , Signal Transduction/drug effects , AMP-Activated Protein Kinases/antagonists & inhibitors , Animals , Antioxidants/pharmacology , Cell Survival/drug effects , Disease Models, Animal , Glutamate-Cysteine Ligase/metabolism , Heme Oxygenase-1/metabolism , Hepatocytes , Interleukin-1beta/metabolism , Interleukin-6/metabolism , Liver/metabolism , Male , Membrane Proteins/metabolism , Mice , NAD(P)H Dehydrogenase (Quinone)/metabolism , Nitric Oxide Synthase Type II/metabolism , Oxazines/pharmacology , Oxidative Stress/drug effects , Tumor Necrosis Factor-alpha/metabolismABSTRACT
Dauricine (Dau) is a natural alkaloid exhibiting anti-proliferative activity against several different types of malignant cell. However, effects of Dau on hepatocellular carcinoma (HCC) cells and the underlying molecular mechanisms have remained to be fully elucidated. In this study, we found that Dau elevated the sensitivities of HCC cells to chemotherapeutic reagents, including cisplatin, sorafenib, and isoliensinine. Moreover, Dau promoted apoptosis of HCC cells triggered by these chemotherapeutic reagents. Consistently, in a xenograft mouse model, Dau sensitized HCC cells to sorafenib. In HCC cells, Dau dose-dependently inhibited glucose glycolysis and increased oxidative phosphorylation. Mechanistically, Dau downregulated the expression of hexokinase 2 (HK2) and pyruvate kinase M2 (PKM2). HK2 and PKM2 can be directly targeted by miR-199a. Dau dose-dependently increased miR-199a expression in HCC cells. Transfection of anti-miR-199a abrogated Dau-mediated suppression of HK2 and PKM2. Dau-induced metabolic shift was thereby severely crippled by anti-miR-199a. In addition, the incremental activity of Dau on sorafenib sensitivity of HCC cells was diminished in response to the transfection of anti-miR-199a. Taken together, our findings provided novel insights into the impact of Dau on HCC cells and supported considering Dau as an adjuvant reagent in the clinical treatment of HCC.