Liver-specific knockout of histone methyltransferase G9a impairs liver maturation and dysregulates inflammatory, cytoprotective, and drug-processing genes
XENOBIOTICA
Authors: Lu, Hong; Lei, Xiaohong; Zhang, Qinghao
Abstract
Methyltransferase G9a is essential for a key gene silencing mark, histone H3 dimethylation at lysine-9 (H3K9me2). Hepatic G9a expression is down-regulated by xenobiotics and diabetes. However, little is known about the role of G9a in liver. Thus, we generated mice with liver-specific knockout (Liv-KO) of G9a. Adult G9a Liv-KO mice had marked loss of H3K9me2 proteins in liver, without overt liver injury or infiltration of inflammatory cells. However, G9a-null livers had ectopic induction of certain genes normally expressed in neural and immune systems. Additionally, G9a-null livers had moderate down-regulation of cytoprotective genes, markedly altered expression of certain important drug-processing genes, elevated endogenous reactive oxygen species, induction of ER stress marker Chop, but decreased glutathione and nuclear Nrf2. microRNA-383, a negative regulator of the PI3K/Akt pathway, was strongly induced in G9a Liv-KO mice. After LPS treatment, G9a Liv-KO mice had aggravated lipid peroxidation and proinflammatory response. Taken together, the present study demonstrates that G9a regulates liver maturation by silencing neural and proinflammatory genes but maintaining/activating cytoprotective and drug-processing genes, in which the G9a/miR-383/PI3K/Akt/Nrf2 (Chop) pathways may play important roles. G9a deficiency due to genetic polymorphism and/or environmental exposure may alter xenobiotic metabolism and aggravate inflammation and liver dysfunction.
Flavokawain A inhibits prostate cancer cells by inducing cell cycle arrest and cell apoptosis and regulating the glutamine metabolism pathway
JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
Authors: Wang, Kaili; Zhang, Weijie; Wang, Zihan; Gao, Ming; Wang, Xinying; Han, Wenchao; Zhang, Nan; Xu, Xia
Abstract
Flavokawain A (FKA), a major chalcone in kava extracts, has exhibited anti-proliferative and apoptotic effects in the prostate cancer. However, the molecular mechanism of FKA remains unclear. In this study, FKA induces cell apoptosis and cell cycle arrest in a G2M phase to prostate cancer cells. FKA interferes with tubulin polymerization and inhibits survivin expression in PC3 cells. Molecular docking simulation experiment finds that FKA can bind to colchicine binding sites that inhibit tubulin polymerization. FKA treatment regulates the glutamine metabolism pathway in PC3 cells by reducing intracellular glutamine, glutamic and proline. FKA treatment also decreases the GSH content by decreasing the activity of GSH synthetase (GSS) and increasing the activity of glutathione thiol transferase (GSTP1), which subsequently induces ROS production and PC3 cell apoptosis. (C) 2020 Elsevier B.V. All rights reserved.