Background Liver cancer ranks the top four malignant cancer type worldwide, which needs effective and safe treatment. Ferroptosis is a novel form of regulated cell death driven by iron-dependent lipid peroxidation and has been regarded as a promising therapeutic target for cancers. In this work, we aimed to study the effects of anesthetic ketamine on proliferation and ferroptosis of liver cancer. Methods Cell viability and proliferation were detected by cell counting kit 8 (CCK-8), colony formation, and 5-ethynyl-2′-deoxyuridine (EdU) assay. Ferroptosis was determined by levels of Fe 2+ , lipid reactive oxygen species (ROS), and malondialdehyde (MDA). RNA levels of lncPVT1, miR-214-3p, and glutathione peroxidase 4 (GPX4) were checked by real-time PCR assay. Clinical liver tumor samples were collected to detect the levels of long noncoding RNA lncPVT1, miR-214-3p, and GPX4, and their correlation was evaluated by Pearson comparison test. Luciferase reporter gene assay and RNA pulldown were conducted to determine the binding between lncPVT1, miR-214-3p, and GPX4 3ʹUTR. Results Ketamine significantly suppressed viability and proliferation of liver cancer cells both in vitro and in vivo, as well as stimulated ferroptosis, along with decreased expression of lncPVT1 and GPX4. LncPVT1 directly interacted with miR-214-3p to impede its role as a sponge of GPX4. Depletion of lncPVT1 accelerated the ferroptosis of live cancer cells, whereas miR-214-3p inhibition and GPX4 overexpression reversed this effect. Ketamine-induced cell growth suppression and ferroptosis were also suppressed by miR-214-3p inhibition and GPX4 overexpression. Conclusion In this work, we determined that ketamine suppressed viability of liver cancer cells and induced ferroptosis and identified the possible regulatory mechanism of lncPVT1/miR-214-3p/GPX4 axis.

No abstract

SummaryMany cellular stresses and inflammatory stimuli can activate p38 mitogenactivated protein kinase (MAPK), a serine/threonine kinase in the MAPK family. The different stimuli act via different receptors or signalling pathways to induce phosphorylation of the cytosolic protein p47 phox , one subunit of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Formylmethionyl-leucyl-phenylalanine (fMLP) has been shown to induce the p38 MAPK phosphorylation during the respiratory burst in human neutrophils. Here, we show that treatment with S(+)-ketamine or R(-)-ketamine at different concentrations (50, 100, 200, 400 mM) reduced fMLP-induced superoxide anion generation and p47 phox phosphorylation in neutrophils in a concentration-dependent manner (y = -0·093x + 93·35 for S(+)-ketamine and y = -0·0982x + 95·603 for R(-)-ketamine, respectively). While treatment with 50 mM ketamine inhibited fMLP-induced superoxide generation by 10%, treatment with 400 mM S(+)-ketamine and R(-)-ketamine reduced fMLPinduced superoxide generation to 60·5 Ϯ 8·3% and 60·0 Ϯ 8·5%, respectively, compared with that in neutrophils treated with fMLP alone. Furthermore, treatment with ketamine down-regulated both fMLP-induced p47 phox and isoproterenol-induced p38 MAPK phosphorylation and superoxide production. Interestingly, treatment with SB203580, the p38 MAPK inhibitor, also mitigated fMLP-induced superoxide anion generation and p38 MAPK and p47 phox phosphorylation as well as apoptosis in a concentrationdependent fashion in neutrophils. Therefore, ketamine racemes inhibited fMLP-induced superoxide anion generation and p47 phox phosphorylation by modulating fMLP-mediated p38 MAPK activation in neutrophils.

No abstract