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Hepatology Communications Nov 2023O-GlcNAcylation is a post-translational modification catalyzed by the enzyme O-GlcNAc transferase, which transfers a single N-acetylglucosamine sugar from UDP-GlcNAc to...
BACKGROUND
O-GlcNAcylation is a post-translational modification catalyzed by the enzyme O-GlcNAc transferase, which transfers a single N-acetylglucosamine sugar from UDP-GlcNAc to the protein on serine and threonine residues on proteins. Another enzyme, O-GlcNAcase (OGA), removes this modification. O-GlcNAcylation plays an important role in pathophysiology. Here, we report that O-GlcNAcylation is essential for hepatocyte differentiation, and chronic loss results in fibrosis and HCC.
METHODS
Single-cell RNA-sequencing (RNA-seq) was used to investigate hepatocyte differentiation in hepatocyte-specific O-GlcNAc transferase-knockout (OGT-KO) mice with decreased hepatic O-GlcNAcylation and in O-GlcNAcase-KO mice with increased O-GlcNAcylation in hepatocytes. Patients HCC samples and the diethylnitrosamine-induced HCC model were used to investigate the effect of modulation of O-GlcNAcylation on the development of liver cancer.
RESULTS
Loss of hepatic O-GlcNAcylation resulted in disruption of liver zonation. Periportal hepatocytes were the most affected by loss of differentiation, characterized by dysregulation of glycogen storage and glucose production. O-GlcNAc transferase-KO mice exacerbated diethylnitrosamine-induced HCC development with increased inflammation, fibrosis, and YAP signaling. Consistently, O-GlcNAcase -KO mice with increased hepatic O-GlcNAcylation inhibited diethylnitrosamine-induced HCC. A progressive loss of O-GlcNAcylation was observed in patients with HCC.
CONCLUSIONS
Our study shows that O-GlcNAcylation is a critical regulator of hepatic differentiation, and loss of O-GlcNAcylation promotes hepatocarcinogenesis. These data highlight increasing O-GlcNAcylation as a potential therapy in chronic liver diseases, including HCC.
Topics: Humans; Mice; Animals; Carcinoma, Hepatocellular; Diethylnitrosamine; Liver Neoplasms; Cell Differentiation; Fibrosis
PubMed: 37930118
DOI: 10.1097/HC9.0000000000000283 -
Cancer Letters Jul 2023Cancer cells use acetate to support the higher demand for energy and lipid biosynthesis during uncontrolled cell proliferation, as well as for acetylation of regulatory...
Cancer cells use acetate to support the higher demand for energy and lipid biosynthesis during uncontrolled cell proliferation, as well as for acetylation of regulatory proteins. Acyl-CoA thioesterase 12 (Acot12) is the enzyme that hydrolyzes acetyl-CoA to acetate in liver cytosol and is downregulated in hepatocellular carcinoma (HCC). A mechanistic role for Acot12 in hepatocarcinogenesis was assessed in mice in response to treatment with diethylnitrosamine(DEN)/carbon tetrachloride (CCl) administration or prolonged feeding of a diet that promotes non-alcoholic steatohepatitis (NASH). Relative to controls, Acot12 mice exhibited accelerated liver tumor formation that was characterized by the hepatic accumulation of glycerolipids, including lysophosphatidic acid (LPA), and that was associated with reduced Hippo signaling and increased yes-associated protein (YAP)-mediated transcriptional activity. In Acot12 mice, restoration of hepatic Acot12 expression inhibited hepatocarcinogenesis and YAP activation, as did knockdown of hepatic YAP expression. Excess LPA produced due to deletion of Acot12 signaled through LPA receptors (LPARs) coupled to Gα12/13 subunits to suppress YAP phosphorylation, thereby promoting its nuclear localization and transcriptional activity. These findings identify a protective role for Acot12 in suppressing hepatocarcinogenesis by limiting biosynthesis of glycerolipids including LPA, which preserves Hippo signaling.
Topics: Animals; Mice; Carcinoma, Hepatocellular; Hippo Signaling Pathway; Liver Neoplasms; Transcription Factors; YAP-Signaling Proteins
PubMed: 37150501
DOI: 10.1016/j.canlet.2023.216210 -
Oncogene Oct 2023The Carbohydrate Response Element (ChoRE) Binding Protein (ChREBP) and its binding partner Max-like protein X (MLX) mediate transcription of lipogenic genes under...
The Carbohydrate Response Element (ChoRE) Binding Protein (ChREBP) and its binding partner Max-like protein X (MLX) mediate transcription of lipogenic genes under glucose-rich conditions. Dysregulation of glucose and lipid metabolism frequently occurs in cancers, including Hepatocellular Carcinomas (HCCs). However, it is currently unclear whether the glucose-induced lipogenic program plays a role in the development of HCCs. Here, we show that MLX expression is elevated in HCC specimens and downregulation of MLX expression inhibits proliferation of HCC cells. In mice, liver-specific knockout of Mlx results in dramatic decrease in the expression of lipogenic genes and lipid levels in circulation. Interestingly, in the absence of Mlx, the development of tumors in multiple HCC models, such as diethylnitrosamine (DEN) treatment and hydrodynamic injection of oncogenes (AKT/RAS or CTNNB1/RAS), is robustly blocked. However, a high-fat diet can partially restore tumorigenesis in Mlx-deficient livers, indicating a critical role of lipid synthesis in HCC development. In addition, liver-specific expression of a dominant negative MLX (dnMLX) via adeno-associated virus effectively blocks tumorigenesis in mice. Thus, the glucose-induced lipogenic program is required in the development of HCC, and the ChREBP: MLX transcription factors serve as a potential target for cancer therapies.
PubMed: 37684408
DOI: 10.1038/s41388-023-02831-2 -
The Journal of Biological Chemistry Oct 2023Circadian rhythms are controlled at the cellular level by a molecular clock consisting of several genes/proteins engaged in a transcription-translation-degradation...
Circadian rhythms are controlled at the cellular level by a molecular clock consisting of several genes/proteins engaged in a transcription-translation-degradation feedback loop. These core clock proteins regulate thousands of tissue-specific genes. Regarding circadian control in neoplastic tissues, reports to date have demonstrated anomalous circadian function in tumor models and cultured tumor cells. We have extended these studies by analyzing circadian rhythmicity genome-wide in a mouse model of liver cancer, in which mice treated with diethylnitrosamine at 15 days develop liver tumors by 6 months. We injected tumor-bearing and control tumor-free mice with cisplatin every 2 h over a 24-h cycle; 2 h after each injection mice were sacrificed and gene expression was measured by XR-Seq (excision repair sequencing) assay. Rhythmic expression of several core clock genes was observed in both healthy liver and tumor, with clock genes in tumor exhibiting typically robust amplitudes and a modest phase advance. Interestingly, although normal hepatic cells and hepatoma cancer cells expressed a comparable number of genes with circadian rhythmicity (clock-controlled genes), there was only about 10% overlap between the rhythmic genes in normal and cancerous cells. "Rhythmic in tumor only" genes exhibited peak expression times mainly in daytime hours, in contrast to the more common pre-dawn and pre-dusk expression times seen in healthy livers. Differential expression of genes in tumors and healthy livers across time may present an opportunity for more efficient anticancer drug treatment as a function of treatment time.
Topics: Animals; Mice; Carcinoma, Hepatocellular; Circadian Rhythm; Liver; Liver Neoplasms; Male; Excision Repair; CLOCK Proteins; Gene Ontology
PubMed: 37714462
DOI: 10.1016/j.jbc.2023.105251 -
Hepatology (Baltimore, Md.) Oct 2023NAFLD is the most common form of liver disease worldwide, but only a subset of individuals with NAFLD may progress to NASH. While NASH is an important etiology of HCC,...
BACKGROUND AND AIMS
NAFLD is the most common form of liver disease worldwide, but only a subset of individuals with NAFLD may progress to NASH. While NASH is an important etiology of HCC, the underlying mechanisms responsible for the conversion of NAFLD to NASH and then to HCC are poorly understood. We aimed to identify genetic risk genes that drive NASH and NASH-related HCC.
APPROACH AND RESULTS
We searched genetic alleles among the 24 most significant alleles associated with body fat distribution from a genome-wide association study of 344,369 individuals and validated the top allele in 3 independent cohorts of American and European patients (N=1380) with NAFLD/NASH/HCC. We identified an rs3747579-TT variant significantly associated with NASH-related HCC and demonstrated that rs3747579 is expression quantitative trait loci of a mitochondrial DnaJ Heat Shock Protein Family (Hsp40) Member A3 ( DNAJA3 ). We also found that rs3747579-TT and a previously identified PNPLA3 as a functional variant of NAFLD to have significant additional interactions with NASH/HCC risk. Patients with HCC with rs3747579-TT had a reduced expression of DNAJA3 and had an unfavorable prognosis. Furthermore, mice with hepatocyte-specific Dnaja3 depletion developed NASH-dependent HCC either spontaneously under a normal diet or enhanced by diethylnitrosamine. Dnaja3 -deficient mice developed NASH/HCC characterized by significant mitochondrial dysfunction, which was accompanied by excessive lipid accumulation and inflammatory responses. The molecular features of NASH/HCC in the Dnaja3 -deficient mice were closely associated with human NASH/HCC.
CONCLUSIONS
We uncovered a genetic basis of DNAJA3 as a key player of NASH-related HCC.
PubMed: 37870291
DOI: 10.1097/HEP.0000000000000637 -
Hepatology Communications Nov 2023Cholesterol levels and bile acid metabolism are important drivers of metabolic dysfunction-associated steatohepatitis (MASH) progression. Using a mouse model, we...
BACKGROUND
Cholesterol levels and bile acid metabolism are important drivers of metabolic dysfunction-associated steatohepatitis (MASH) progression. Using a mouse model, we investigated the mechanism by which cholesterol exacerbates MASH and the effect of colestyramine (a bile acid adsorption resin) and elobixibat (an apical sodium-dependent bile acid transporter inhibitor) concomitant administration on bile acid adsorption and MASH status.
METHODS
Mice were fed a high-fat high-fructose diet with varying concentrations of cholesterol to determine changes in fatty liver according to liver status, water intake, defecation status, insulin resistance, bile acid levels, intestinal permeability, atherosclerosis (in apolipoprotein E knockout mice), and carcinogenesis (in diethylnitrosamine mice). Using small interfering ribonucleic acid (siRNA), we evaluated the effect of sterol regulatory element binding protein 1c (SREBP1c) knockdown on triglyceride synthesis and fatty liver status following the administration of elobixibat (group E), colestyramine (group C), or both (group EC).
RESULTS
We found greater reductions in serum alanine aminotransferase levels, serum lipid parameters, serum primary bile acid concentrations, hepatic lipid levels, and fibrosis area in EC group than in the monotherapy groups. Increased intestinal permeability and watery diarrhea caused by elobixibat were completely ameliorated in group EC. Group EC showed reduced plaque formation rates in the entire aorta and aortic valve of the atherosclerosis model, and reduced tumor counts and tumor burden in the carcinogenesis model.
CONCLUSIONS
Excessive free cholesterol in the liver can promote fatty liver disease. Herein, combination therapy with EC effectively reduced free cholesterol levels in MASH model mice. Our study provides strong evidence for combination therapy as an effective treatment for MASH.
Topics: Animals; Mice; Cholestyramine Resin; Bile Acids and Salts; Non-alcoholic Fatty Liver Disease; Disease Models, Animal; Atherosclerosis; Carcinogenesis
PubMed: 37902528
DOI: 10.1097/HC9.0000000000000285 -
Hepatology Communications Sep 2023Hepatocellular carcinoma (HCC) is associated with chronic inflammation caused by different factors; especially, the interaction of inflammatory pathways and bile acids...
BACKGROUND
Hepatocellular carcinoma (HCC) is associated with chronic inflammation caused by different factors; especially, the interaction of inflammatory pathways and bile acids (BAs) can affect hepatocyte proliferation, death, and regeneration, but whether BAs promote HCC progression through inflammatory pathways and the mechanisms is still unclear.
METHODS AND RESULTS
By examining cancer and tumor-adjacent tissue BA levels and genes associated with BA homeostasis in 37 HCC patients, we found that total bile acids (TBAs) were decreased by 36% and varying degrees of changes in factors regulating BA homeostasis (p < 0.05). In addition, we found that BA homeostasis was disturbed in diethylnitrosamine-induced HCC mouse models, and TBA was correlated with inflammasome activation during HCC progression (6-24 W) (p < 0.05). Similarly, the inflammasome and chenodeoxycholic acid (CDCA) content were suppressed in cholestasis model mice (Mrp2-deficient mice) (p < 0.05). In vitro, CDCA significantly promoted the malignant transformation of hepatocytes (p < 0.001), activated the inflammasome by triggering the release of mitochondrial reactive oxygen species and mitochondrial DNA, and ultimately induced pyroptosis. Furthermore, we found that CDCA has a targeted binding effect with HO-1 through molecular docking and Cellular Thermal Shift Assay experiments.
CONCLUSIONS
In conclusion, we found that CDCA can trigger the excessive accumulation of mitochondrial reactive oxygen species by targeting HO-1 to promote the activation of the inflammasome and ultimately promote the progression of HCC. Our study provides a novel mechanism by which BAs promote HCC by activating the inflammasome and establishes the important role of BA homeostasis imbalance in the progression of HCC from the aspect of inflammation.
Topics: Mice; Animals; Bile Acids and Salts; Carcinoma, Hepatocellular; Inflammasomes; Reactive Oxygen Species; Molecular Docking Simulation; Cells, Cultured; Liver Neoplasms; Chenodeoxycholic Acid; Inflammation
PubMed: 37556375
DOI: 10.1097/HC9.0000000000000217 -
Archives of Biochemistry and Biophysics Sep 2023Hepatocellular carcinoma (HCC) is the leading cause of cancer-related death worldwide. Cytochrome P450 2E1 (CYP2E1) is an enzyme, primarily involved in the metabolism of...
Hepatocellular carcinoma (HCC) is the leading cause of cancer-related death worldwide. Cytochrome P450 2E1 (CYP2E1) is an enzyme, primarily involved in the metabolism of xenobiotics and procarcinogens. The present study was designed to investigate the potential role of CYP2E1 triggered endoplasmic reticulum stress in the progression of HCC through inhibition of apoptosis. In vitro CYP2E1 promotes HepG2 cell migration, reduced chromatin condensation, enhanced intracellular ROS accumulation and induce cell cycle progression. Conversely this effect was averted by CYP2E1 siRNA, selective inhibitor Diallyl sulphide (DAS) and antioxidants (vitamin C and E). In vivo Diethylnitrosamine (DEN) induced HCC rats showed decreased body weight and increased relative liver weight. Moreover, macro trabecular-massive HCC (MTM-HCC) histological subtyping showed pathological features like well-differentiated tumors, micro-trabecular and pseudo glandular patterns, megakaryocytes and cholestasis. Masson's trichrome staining revealed an intensive accumulation of collagen fibers in the extracellular matrix (ECM). Increased CYP2E1, VEGF and PCNA enhance the carcinogenicity as revealed in immunohistochemistry results. Immunoblot analysis showed reduced expression of copper-zinc superoxide dismutase (CuZnSOD) and manganese superoxide dismutase (MnSOD) in cytosolic as well as mitochondrial fraction of rat liver tissue respectively. Also, increased level of CYP2E1 stimulated the upregulation of unfolded proteins response (UPR) and ER stress-related proteins such as Glucose regulatory protein 78 (GRP78), activating transcription factor 6 (ATF6) and CCAAT enhancer-binding protein (C/EBP) homologous protein (CHOP). Meanwhile, CYP2E1 stimulated ER-stress reduces BCL2 and downregulates the cleaved caspase 3 thus suppresses apoptosis. in. Furthermore, immunofluorescence revealed increased expression level of α-SMA in the HCC rat liver tissue. The level of CYP2E1 mRNA was significantly increased. Altogether, these findings indicate that CYP2E1 has a dynamic role in the pathogenesis of HCC and might be a budding agent in liver carcinogenesis therapy.
Topics: Animals; Rats; Activating Transcription Factor 6; Apoptosis; Carcinoma, Hepatocellular; Cytochrome P-450 CYP2E1; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Heat-Shock Proteins; Liver Neoplasms; Transcription Factors; Transcription Factor CHOP; Humans
PubMed: 37499993
DOI: 10.1016/j.abb.2023.109701 -
Frontiers in Immunology 2023Tumor-initiating cells (TICs) are rare, stem-like, and highly malignant. Although intravenous hepatitis B and C immunoglobulins have been used for HBV and HCV...
INTRODUCTION
Tumor-initiating cells (TICs) are rare, stem-like, and highly malignant. Although intravenous hepatitis B and C immunoglobulins have been used for HBV and HCV neutralization in patients, their tumor-inhibitory effects have not yet been examined. Hepatitis B immunoglobulin (HBIG) therapy is employed to reduce hepatocellular carcinoma (HCC) recurrence in patients after living donor liver transplantations (LDLT).
HYPOTHESIS
We hypothesized that patient-derived intravenous immunoglobulin (IVIG) binding to HCC associated TICs will reduce self-renewal and cell viability driven by β-CATENIN-downstream pathways. β-CATENIN activity protected TICs from IVIG effects.
METHODS
The effects of HBIG and HCIG binding to TICs were evaluated for cell viability and self-renewal.
RESULTS
Inhibition of β-CATENIN pathway(s) augmented TIC susceptibility to HBIG- and HCIG-immunotherapy. HBV X protein (HBx) upregulates both β-CATENIN and NANOG expression. The co-expression of constitutively active β-CATENIN with NANOG promotes self-renewal ability and tumor-initiating ability of hepatoblasts. HBIG bound to HBV+ cells led to growth inhibition in a TIC subset that expressed hepatitis B surface antigen. The HBx protein transformed cells through β-CATENIN-inducible lncRNAs and . Co-expression of constitutively active β-CATENIN with NANOG promoted self-renewal ability of TICs through EGLN3 induction. β-CATENIN-induced lncRNAs stabilized HIF2 to maintain self-renewal of TICs. Targeting of resulted in destabilization of EZH2-dependent β-CATENIN activity and synergized cell-killing of TICs by HBIG or HCIG immunotherapy.
DISCUSSION
Taken together, WNT and stemness pathways induced HIF2 of TICs via cooperating lncRNAs resulting in resistance to cancer immunotherapy. Therefore, therapeutic use of IVIG may suppress tumor recurrence through inhibition of TICs.
Topics: Humans; beta Catenin; Carcinoma, Hepatocellular; Immunoglobulins, Intravenous; Immunotherapy; Liver Neoplasms; Liver Transplantation; Living Donors; Neoplasm Recurrence, Local; RNA, Long Noncoding
PubMed: 37744383
DOI: 10.3389/fimmu.2023.1204907 -
Metabolism: Clinical and Experimental Mar 2024Hepatocellular carcinoma (HCC) continues to pose a significant health challenge and is often diagnosed at advanced stages. Metabolic reprogramming is a hallmark of many...
BACKGROUND
Hepatocellular carcinoma (HCC) continues to pose a significant health challenge and is often diagnosed at advanced stages. Metabolic reprogramming is a hallmark of many cancer types, including HCC and it involves alterations in various metabolic or nutrient-sensing pathways within liver cells to facilitate the rapid growth and progression of tumours. However, the role of STAT3-NFκB in metabolic reprogramming is still not clear.
APPROACH AND RESULTS
Diethylnitrosamine (DEN) administered animals showed decreased body weight and elevated level of serum enzymes. Also, Transmission electron microscopy (TEM) analysis revealed ultrastructural alterations. Increased phosphorylated signal transducer and activator of transcription-3 (p-STAT3), phosphorylated nuclear factor kappa B (p-NFκβ), dynamin related protein 1 (Drp-1) and alpha-fetoprotein (AFP) expression enhance the carcinogenicity as revealed in immunohistochemistry (IHC). The enzyme-linked immunosorbent assay (ELISA) concentration of IL-6 was found to be elevated in time dependent manner both in blood serum and liver tissue. Moreover, immunoblot analysis showed increased level of p-STAT3, p-NFκβ and IL-6 stimulated the upregulation of mitophagy proteins such as Drp-1, Phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK-1). Meanwhile, downregulation of Poly [ADP-ribose] polymerase 1 (PARP-1) and cleaved caspase 3 suppresses apoptosis and enhanced expression of AFP supports tumorigenesis. The mRNA level of STAT3 and Drp-1 was also found to be significantly increased. Furthermore, we performed high-field 800 MHz Nuclear Magnetic Resonance (NMR) based tissue and serum metabolomics analysis to identify metabolic signatures associated with the progression of liver cancer. The metabolomics findings revealed aberrant metabolic alterations in liver tissue and serum of 75th and 105th days of intervention groups in comparison to control, 15th and 45th days of intervention groups. Tissue metabolomics analysis revealed the accumulation of succinate in the liver tissue samples, whereas, serum metabolomics analysis revealed significantly decreased circulatory levels of ketone bodies (such as 3-hydroxybutyrate, acetate, acetone, etc.) and membrane metabolites suggesting activated ketolysis in advanced stages of liver cancer.
CONCLUSION
STAT3-NFκβ signaling axis has a significant role in mitochondrial dysfunction and metabolic alterations in the development of HCC.
Topics: Animals; alpha-Fetoproteins; Carcinoma, Hepatocellular; Cell Line, Tumor; Interleukin-6; Liver Neoplasms; Mitochondrial Diseases; NF-kappa B; STAT3 Transcription Factor; Signal Transduction
PubMed: 38184165
DOI: 10.1016/j.metabol.2023.155771