Andrographolide causes p53-independent HCC cell death through p62 accumulation and impaired DNA damage repair.

BACKGROUND: Hepatocellular carcinoma (HCC) is a highly lethal cancer characterized by dominant driver mutations, including p53. Consequently, there is an urgent need to search for novel therapeutic agents to treat HCC. Andrographolide (Andro), a clinically available anti-inflammatory phytochemical agent, has shown inhibitory effects against various types of cancer, including HCC. However, the underlying molecular mechanisms of its action remain poorly understood. PURPOSE: This study aims to investigate the molecular mechanisms by which p53 and p62 collectively affect Andro-induced HCC cell death, using both in vitro and in vivo models. METHODS: In vitro cellular experiments were conducted to examine the effects of Andro on cell viability and elucidate its mechanisms of action. In vivo xenograft experiments further validated the anti-cancer effects of Andro. RESULTS: Andro induced dose- and time-dependent HCC cell death while sparing normal HL-7702 hepatocytes. Furthermore, Andro caused DNA damage through the generation of reactive oxygen species (ROS), a critical event leading to cell death. Notably, HCC cells expressing p53 exhibited greater resistance to Andro-induced cell death compared to p53-deficient cells, likely due to the ability of p53 to induce G2/M cell cycle arrest. Additionally, Andro-induced p62 aggregation led to the proteasomal degradation of RAD51 and 53BP1, two key proteins involved in DNA damage repair. Consequently, silencing or knocking out p62 facilitated DNA damage repair and protected HCC cells. Importantly, disruption of either p53 or p62 did not affect the expression of the other protein. These findings were further supported by the observation that xenograft tumors formed by p62-knockout HCC cells displayed increased resistance to Andro treatment. CONCLUSION: This study elucidates the mechanistic basis of Andro-induced HCC cell death. It provides valuable insights for repurposing Andro for the treatment of HCC, regardless of the presence of functional p53.

High-Fat Diet-Induced Fatty Liver Is Associated with Immunosuppressive Response during Sepsis in Mice.

High-fat diet-induced fatty liver is an indolent and chronic disease accompanied by immune dysfunction and metabolic disturbances involving numerous biological pathways. This study investigated how this abnormal metabolic disorder influences sepsis in mice. Mice were fed with normal chow (NC) or high-fat diet (HFD), and palmitic acid (PA) was used to treat hepatocytes to mimic fat accumulation in vitro. Lipopolysaccharide (LPS) was used to induce sepsis and related immune responses. Mice fed on a high-fat diet displayed higher mortality and more severe liver damage but compromised immunoreaction. The supernatant from PA-treated primary hepatocytes markedly diminished the inflammatory cytokine expression of macrophages after LPS stimulation, which showed a state of immunosuppression. Metabolomics analysis indicated the level of many key metabolites with possible roles in immunoreaction was altered in the HFD and PA groups compared with corresponding controls; specifically, ß-hydroxybutyric acid (BHB) showed an immunosuppressive effect on Raw264.7 cells during the LPS stimulation. Transcriptomic analysis suggested that several differential signaling pathways may be associated with the alteration of immune function between the NC and HFD groups, as well as in the in vitro model. Our study suggests that the consumption of HFD may alter the hepatic metabolic profile, and that certain metabolites may remold the immune system to immunosuppressive state in the context of sepsis.

[Gut microbiota-an important contributor to liver diseases].

Gut microbiota constitute a complicated but manifold ecosystem, in which specific symbiotic relationships are formed among various bacteria. To maintain a steady state, the gastrointestinal tract and the liver form a close anatomical and functional two-way, interconnected network through the portal circulation. "Gut-liver axis" plays a key role in the pathogenesis of liver diseases. Accumulating evidence indicates that gut microbiota can influence the liver pathophysiology directly or indirectly via a variety of signal pathways. In a pathological state where an ecological imbalance occurs at the compositional and functional levels, gut microbes would interact with the host immune system and other type of cells to cause liver steatosis, inflammation and fibrosis, which in turn give rise to the development of such liver diseases as alcoholic liver disease, nonalcoholic fatty liver disease, primary sclerosing cholangitis, and acute liver failure, to name a few. Studies have shown that microorganisms, such as prebiotics and probiotics, can improve the prognosis of certain diseases, which open a new era of treating liver diseases with bacteria. There are many unknowns and hidden values in the gut microbiome. To explore the pathophysiological mechanism of various complex diseases and develop scientific and effective clinical treatment strategies, efforts should be made to obtain insights into how certain intestinal microbiota participates in the occurrence and progression of liver diseases. As the connection between gut microbiota and liver diseases at both the acute and chronic phases was not elaborated in previously published review articles, herein we discuss the association between gut microbiota and both acute and chronic liver injury. The anatomical structure of the liver enables it to form a close network with the gut microbiota, which is an important mediator in the regulation of the hepatic physiological and pathological functions.