glycogen and Liver-Neoplasms

The liver is a major store of glycogen and is essential in maintaining systemic glucose homeostasis. In healthy individuals, glycogen synthesis and breakdown in the liver are tightly regulated. Abnormal glycogen metabolism results in prominent pathological changes in the liver, often manifesting as hepatic glycogenosis or glycogen inclusions. This can occur in genetic glycogen storage disease or acquired conditions with insulin dysregulation such as diabetes mellitus and non-alcoholic fatty liver disease or medication effects. Some primary hepatic tumors such as clear cell hepatocellular carcinoma also demonstrate excessive glycogen accumulation. This review provides an overview of the pathological manifestations and molecular mechanisms of liver diseases associated with abnormal glycogen accumulation.

Topics: Carcinoma, Hepatocellular; Glycogen; Glycogen Storage Disease; Humans; Liver; Liver Neoplasms

Clear cell hepatocellular carcinoma (CCHCC) has hitherto been considered an uncommon, highly differentiated variant of hepatocellular carcinoma (HCC) with a relatively favorable prognosis. CCHCC is composed of mixtures of clear and/or acidophilic ground glass hepatocytes with excessive glycogen and/or fat and shares histology, clinical features and etiology with common HCCs. Studies in animal models of chemical, hormonal and viral hepatocarcinogenesis and observations in patients with chronic liver diseases prone to develop HCC have shown that the majority of HCCs are preceded by, or associated with, focal or diffuse excessive storage of glycogen (glycogenosis) which later may be replaced by fat (lipidosis/steatosis). In ground glass cells, the glycogenosis is accompanied by proliferation of the smooth endoplasmic reticulum, which is closely related to glycogen particles and frequently harbors the hepatitis B surface antigen (HBsAg). From the findings in animal models a sequence of changes has been established, commencing with preneoplastic glycogenotic liver lesions, often containing ground glass cells, and progressing to glycogen-poor neoplasms via various intermediate stages, including glycogenotic/lipidotic clear cell foci, clear cell hepatocellular adenomas (CCHCA) rich in glycogen and/or fat, and CCHCC. A similar process seems to take place in humans, with clear cells frequently persisting in CCHCC and steatohepatitic HCC, which presumably represent intermediate stages in the development rather than particular variants of HCC. During the progression of the preneoplastic lesions, the clear and ground glass cells transform into cells characteristic of common HCC. The sequential cellular changes are associated with metabolic aberrations, which start with an activation of the insulin signaling cascade resulting in pre-neoplastic hepatic glycogenosis. The molecular and metabolic changes underlying the glycogenosis/lipidosis are apparently responsible for the dramatic metabolic shift from gluconeogenesis to the pentose phosphate pathway and Warburg-type glycolysis, which provide precursors and energy for an ever increasing cell proliferation during progression.

Topics: Animals; Carcinoma, Hepatocellular; Cell Proliferation; Cell Transformation, Neoplastic; Disease Progression; Energy Metabolism; Glycogen; Humans; Liver Neoplasms; Phenotype; Precancerous Conditions

Topics: Glucose; Glucose Intolerance; Glucose Tolerance Test; Glycogen; Humans; Insulin Resistance; Liver; Liver Cirrhosis; Liver Neoplasms; Muscle, Skeletal; Nutrition Therapy

Biochemical and molecular biological approaches in situ have provided compelling evidence for early bioenergetic changes in hepatocarcinogenesis. Hepatocellular neoplasms regularly develop from preneoplastic foci of altered hepatocytes, irrespective of whether they are caused by chemicals, radiation, viruses, or transgenic oncogenes. Two striking early metabolic aberrations were discovered: (1) a focal excessive storage of glycogen (glycogenosis) leading via various intermediate stages to neoplasms, the malignant phenotype of which is poor in glycogen but rich in ribosomes (basophilic), and (2) an accumulation of mitochondria in so-called oncocytes and amphophilic cells, giving rise to well-differentiated neoplasms. The metabolic pattern of human and experimentally induced focal hepatic glycogenosis mimics the phenotype of hepatocytes exposed to insulin. The conversion of the highly differentiated glycogenotic hepatocytes to the poorly differentiated cancer cells is usually associated with a reduction in gluconeogenesis, an activation of the pentose phosphate pathway and glycolysis, and an ever increasing cell proliferation. The metabolic pattern of preneoplastic amphophilic cell populations has only been studied to a limited extent. The few available data suggest that thyromimetic effects of peroxisomal proliferators and hepadnaviral infection may be responsible for the emergence of the amphophilic cell lineage of hepatocarcinogenesis. The actions of both insulin and thyroid hormone are mediated by intracellular signal transduction. It is, thus, conceivable that the early changes in energy metabolism during hepatocarcinogenesis are the consequence of alterations in the complex network of signal transduction pathways, which may be caused by genetic as well as epigenetic primary lesions, and elicit adaptive metabolic changes eventually resulting in the malignant neoplastic phenotype.

Topics: Animals; Carcinoma, Hepatocellular; Cell Transformation, Neoplastic; Energy Metabolism; Glycogen; Humans; Insulin; Liver; Liver Neoplasms; Thyroid Hormones

Topics: Animals; Candida albicans; Carbohydrate Metabolism; Carcinoma, Hepatocellular; Cells; Citric Acid Cycle; Dictyostelium; Glycogen; Homeostasis; Liver; Liver Neoplasms; Models, Biological; Rats

Topics: Animals; Antigens, Neoplasm; Basophils; Carbohydrate Metabolism; Carbohydrate Metabolism, Inborn Errors; Carcinogens; Dose-Response Relationship, Drug; Glycogen; Glycogen Storage Disease; Iron; Liver; Liver Neoplasms; Microscopy, Electron; Rats

Topics: Amino Acids; Animals; Bile Acids and Salts; Carboxy-Lyases; Carcinoma, Hepatocellular; Cell Differentiation; Cholesterol; Citric Acid Cycle; Deoxyribonucleases; DNA Nucleotidyltransferases; DNA-Directed RNA Polymerases; Fatty Acids; Glycogen; Glycolysis; Hexosamines; Humans; Isoenzymes; Ketone Bodies; Liver Neoplasms; Neoplasms, Experimental; Pentoses; Phosphoric Monoester Hydrolases; Phosphotransferases; Ribonucleases; Transaminases

Topics: Acetamides; Azo Compounds; Biological Transport, Active; Carcinogens; Carcinoma, Hepatocellular; Cells, Cultured; Chondroitin; Ethionine; Glucose; Glycogen; Glycosaminoglycans; Heparin; Histocytochemistry; Hyaluronic Acid; Liver; Liver Glycogen; Liver Neoplasms; Microscopy, Electron; Neoplasm Transplantation; Neoplasms; Neoplasms, Experimental; Nitrosamines; Polysaccharides; Radiation Effects

Topics: Animals; Carcinoma, Ehrlich Tumor; Carcinoma, Hepatocellular; Fructose-Bisphosphatase; Glycogen; Humans; Liver; Liver Neoplasms; Muscles; Neoplasms, Experimental

Topics: Adenosine Triphosphate; Animals; Biological Transport, Active; Carcinoma, Ehrlich Tumor; Carcinoma, Hepatocellular; Cholesterol; Diethylstilbestrol; DNA; Enzyme Induction; Enzyme Repression; Feedback; Glycogen; Glycolysis; Hexokinase; Isocitrate Dehydrogenase; L-Lactate Dehydrogenase; Liver; Liver Neoplasms; Malate Dehydrogenase; NAD; NADP; Neoplasms; Oxygen; Phosphates; Phosphofructokinase-1

Topics: Amino Acids; Animals; Biochemical Phenomena; Biochemistry; Carbohydrate Metabolism; Carbon Isotopes; Carcinoma, Hepatocellular; DNA; Ethionine; Fatty Acids; Glucocorticoids; Gluconeogenesis; Glucose; Glycogen; Glycolysis; Growth; Kinetics; Lactates; Lipid Metabolism; Liver Neoplasms; Pentosephosphates; Phosphofructokinase-1; Protein Biosynthesis; Rats; RNA; Thymidine; Triamcinolone

Temporary occlusion of liver blood supply for complex liver operation is common in liver surgery. However, hepatic vascular occlusion will undoubtedly impair liver function. This study was designed to elucidate the effect of hepatocellular glycogen in alleviation of liver ischemia-reperfusion injury during hepatic vascular occlusion for partial hepatectomy.. Fifty-seven patients were randomly divided into an experimental group (n = 29) and a control group (n = 28). In the experimental group, patients were given high-concentration glucose intravenously during 24 h before the operation. The hepatic lesion was resected after portal triad clamping in the two groups. Noncancer liver tissue was biopsied to measure hepatic tissue ATP content and change of malondialdehyde (MDA) and superoxide dismutase (SOD). Liver function of all patients was assessed by using an automatic biochemical analysis apparatus before the operation and the first and fifth days after operation.. The mean hepatic vascular occlusion time in the experimental group was 19.21 +/- 4.54 min and in the control group it was 21.04 +/- 5.11 min. Hepatic tissue ATP content of the experimental group was significantly higher than that of the control group at the end of hepatic vascular occlusion (2.15 +/- 0.39 mumol/g wet tissue vs. 1.33 +/- 0.44, p < 0.01) and at the point of 1-h reperfusion (2.19 +/- 0.29 mumol/g wet tissue vs. 1.57 +/- 0.35, p < 0.01). There was significant difference in SOD activity between the two groups at the end of hepatic vascular occlusion (130.69 +/- 30.49 NU/mg pr vs. 97.83 +/- 26.23, p < 0.01) and at the point of 1-h reperfusion (139.55 +/- 39.88 NU/mg pr vs. 114.74 +/- 25.93, p < 0.01). Significant difference was shown in MDA content between the two groups at the end of hepatic vascular occlusion (3.02 +/- 0.30 nmol/mg pr vs. 3.99 +/- 0.49, p < 0.01) and at the point of 1-h reperfusion (3.81 +/- 0.69 nmol/mg pr vs. 5.75 +/- 1.17, p < 0.01). In addition, the liver function of the experimental group was significantly better than that of the control group the first and fifth days after the operation (p < 0.01).. Abundant intracellular glycogen may reduce liver ischemia-reperfusion injury caused by hepatic vascular occlusion. It is beneficial to give a large amount of glucose before a complex liver operation during which temporary occlusion of hepatic blood flow is necessary.

Topics: Adult; Female; Glycogen; Hepatectomy; Humans; Liver; Liver Cirrhosis; Liver Neoplasms; Male; Malondialdehyde; Middle Aged; Reperfusion Injury; Superoxide Dismutase

Topics: Carcinoma, Hepatocellular; Cell Line, Tumor; Glycogen; Humans; Liver Neoplasms; Osteopontin

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths. There is an urgent need for new targets to treat HCC due to limited treatment options and drug resistance. Many cancer cells are known to have high amount of glycogen than their tissue of origin and inhibition of glycogen catabolism induces cancer cell death by apoptosis. To further understand the role of glycogen in HCC and target it for pharmacotherapy, we studied metabolic adaptations and mitochondrial function in HepG2 cells after pharmacological inhibition of glycogen phosphorylase (GP) by CP-91149 (CP). GP inhibition increased the glycogen levels in HepG2 cells without affecting overall glucose uptake. Glycolytic capacity and importantly glycolytic reserve decreased significantly. Electron microscopy revealed that CP treatment altered mitochondrial morphology leading to mitochondrial swelling with less defined cristae. A concomitant decrease in mitochondrial oxygen consumption and mitochondria-linked ATP generation was observed. Metabolomics and enzyme activity / expression studies showed a decrease in the pentose phosphate pathway. In addition, CP treatment decreased the growth of HepG2 3D tumor spheroids in a dose- and time-dependent manner. Taken together, our study provides insights into metabolic alterations and mitochondrial dysfunction accompanying apoptosis in HepG2 cells upon GP inhibition. Our study can aid in the understanding of the mechanism and development of metabolic inhibitors to treat HCC.

Topics: Apoptosis; Carcinoma, Hepatocellular; Glycogen; Glycogen Phosphorylase; Humans; Liver Neoplasms; Mitochondria

Novel and accurate biomarkers are needed for early detection and progression evaluation of hepatocellular carcinoma (HCC). Protein phosphatase 1 regulatory subunit 1A (PPP1R1A) has been studied in cancer biology; however, the expression pattern and biological function of PPP1R1A in HCC are unclear. The differentially expressed genes (DEGs) in HCC were screened by The Cancer Genome Atlas (TCGA) database. Real-time PCR and immunohistochemistry (IHC) assay were used to detect the expression of PPP1R1A in BALB/c mice, human normal tissues and corresponding tumor tissues, especially HCC. Then, Kaplan-Meier analysis of patients with HCC was performed to evaluate the relationship between PPP1R1A expression and prognosis. The transcriptional regulatory network of PPP1R1A was constructed based on the differentially expressed mRNAs, microRNAs and transcription factors (TFs). To explore the downstream regulation of PPP1R1A, the Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis and immune infiltration score were performed. A total of 4 DEGs were screened out. PPP1R1A was differentially distributed and expressed in BALB/c mice and human tissues. PPP1R1A expression was higher in normal tissues than that in tumor tissues, and patients with higher PPP1R1A expression had better clinical outcome in HCC. In addition, we constructed miR-21-3p/TAL1/PPP1R1A transcriptional network. Furthermore, PPP1R1A may modulate the activation of PI3K-Akt pathway, cell cycle, glycogen metabolism and the recruitment of M2 macrophage in HCC. This study may help to clarify the function and mechanism of PPP1R1A in HCC and provide a potential biomarker for tumor prevention and treatment.

Topics: Animals; Biomarkers, Tumor; Carcinoma, Hepatocellular; Computational Biology; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Glycogen; Humans; Liver Neoplasms; Mice; MicroRNAs; Phosphatidylinositol 3-Kinases; Prognosis; Protein Phosphatase 1; Proto-Oncogene Proteins c-akt; Transcription Factors

Glucose consumption is generally increased in tumor cells to support tumor growth. Interestingly, we report that glycogen accumulation is a key initiating oncogenic event during liver malignant transformation. We found that glucose-6-phosphatase (G6PC) catalyzing the last step of glycogenolysis is frequently downregulated to augment glucose storage in pre-malignant cells. Accumulated glycogen undergoes liquid-liquid phase separation, which results in the assembly of the Laforin-Mst1/2 complex and consequently sequesters Hippo kinases Mst1/2 in glycogen liquid droplets to relieve their inhibition on Yap. Moreover, G6PC or another glycogenolysis enzyme-liver glycogen phosphorylase (PYGL) deficiency in both human and mice results in glycogen storage disease along with liver enlargement and tumorigenesis in a Yap-dependent manner. Consistently, elimination of glycogen accumulation abrogates liver growth and cancer incidence, whereas increasing glycogen storage accelerates tumorigenesis. Thus, we concluded that cancer-initiating cells adapt a glycogen storing mode, which blocks Hippo signaling through glycogen phase separation to augment tumor incidence.

Topics: Adult; Aged; Aged, 80 and over; Animals; Carcinogenesis; Cell Line; Disease Models, Animal; Down-Regulation; Female; Gene Expression Regulation, Neoplastic; Glucose-6-Phosphatase; Glycogen; Glycogen Phosphorylase; Hepatocyte Growth Factor; Hippo Signaling Pathway; Humans; Liver; Liver Neoplasms; Male; Mice, Inbred C57BL; Mice, Knockout; Middle Aged; Neoplasm Staging; Phase Transition; Precancerous Conditions; Protein Tyrosine Phosphatases, Non-Receptor; Proto-Oncogene Proteins; Serine-Threonine Kinase 3; YAP-Signaling Proteins

In the rat, the pancreatic islet transplantation model is an established method to induce hepatocellular carcinomas (HCC), due to insulin-mediated metabolic and molecular alterations like increased glycolysis and de novo lipogenesis and the oncogenic AKT/mTOR pathway including upregulation of the transcription factor Carbohydrate-response element-binding protein (ChREBP). ChREBP could therefore represent an essential oncogenic co-factor during hormonally induced hepatocarcinogenesis.. Pancreatic islet transplantation was implemented in diabetic C57Bl/6J (wild type, WT) and ChREBP-knockout (KO) mice for 6 and 12 months. Liver tissue was examined using histology, immunohistochemistry, electron microscopy and Western blot analysis. Finally, we performed NGS-based transcriptome analysis between WT and KO liver tumor tissues.. Three hepatocellular carcinomas were detectable after 6 and 12 months in diabetic transplanted WT mice, but only one in a KO mouse after 12 months. Pre-neoplastic clear cell foci (CCF) were also present in liver acini downstream of the islets in WT and KO mice. In KO tumors, glycolysis, de novo lipogenesis and AKT/mTOR signalling were strongly downregulated compared to WT lesions. Extrafocal liver tissue of diabetic, transplanted KO mice revealed less glycogen storage and proliferative activity than WT mice. From transcriptome analysis, we identified a set of transcripts pertaining to metabolic, oncogenic and immunogenic pathways that are differentially expressed between tumors of WT and KO mice. Of 315 metabolism-associated genes, we observed 199 genes that displayed upregulation in the tumor of WT mice, whereas 116 transcripts showed their downregulated expression in KO mice tumor.. The pancreatic islet transplantation model is a suitable method to study hormonally induced hepatocarcinogenesis also in mice, allowing combination with gene knockout models. Our data indicate that deletion of ChREBP delays insulin-induced hepatocarcinogenesis, suggesting a combined oncogenic and lipogenic function of ChREBP along AKT/mTOR-mediated proliferation of hepatocytes and induction of hepatocellular carcinoma.

Topics: Animals; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; Carcinogenesis; Carcinoma, Hepatocellular; Cell Proliferation; Diabetes Mellitus, Experimental; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Glycogen; Glycolysis; Hormones; Lipogenesis; Liver; Liver Neoplasms; Male; Mice, Inbred C57BL; Mice, Knockout; RNA, Messenger

Topics: Glycogen; Humans; Liver; Liver Neoplasms

Abnormal glucose metabolism may contribute to cancer progression. As a member of the CRK (v-crk sarcoma virus CT10 oncogene homologue) adapter protein family, CRKL (CRK-like) associated with the development and progression of various tumours. However, the exact role and underlying mechanism of CRKL on energy metabolism remain unknown. In this study, we investigated the effect of CRKL on glucose metabolism of hepatocarcinoma cells. CRKL and PI3K were found to be overexpressed in both hepatocarcinoma cells and tissues; meanwhile, CRKL up-regulation was positively correlated with PI3K up-regulation. Functional investigations revealed that CRKL overexpression promoted glucose uptake, lactate production and glycogen synthesis of hepatocarcinoma cells by up-regulating glucose transporters 1 (GLUT1), hexokinase II (HKII) expression and down-regulating glycogen synthase kinase 3β (GSK3β) expression. Mechanistically, CRKL promoted glucose metabolism of hepatocarcinoma cells via enhancing the CRKL-PI3K/Akt-GLUT1/HKII-glucose uptake, CRKL-PI3K/Akt-HKII-glucose-lactate production and CRKL-PI3K/Akt-Gsk3β-glycogen synthesis. We demonstrate CRKL facilitates HCC malignancy via enhancing glucose uptake, lactate production and glycogen synthesis through PI3K/Akt pathway. It provides interesting fundamental clues to CRKL-related carcinogenesis through glucose metabolism and offers novel therapeutic strategies for hepatocarcinoma.

Topics: Adaptor Proteins, Signal Transducing; Carcinoma, Hepatocellular; Cell Line, Tumor; Disease Susceptibility; Gene Expression Regulation, Neoplastic; Glucose; Glycogen; Humans; Liver Neoplasms; Phosphatidylinositol 3-Kinases; Proteomics; Proto-Oncogene Proteins c-akt; Signal Transduction

Ground-glass (GG) hepatocytes are classically associated with chronic hepatitis B (HBV) infection, storage disorders, or cyanamide therapy. In a subset of cases, an exact etiology cannot be identified. In this study, we sought to characterize the clinical, histological, and ultrastructural findings associated with HBV-negative GG hepatocytes. Our institutional laboratory information system was searched from 2000 to 2019 for all cases of ground-glass hepatocytes. Ten liver biopsies with GG hepatocellular inclusions and negative HBV serology, no known history of storage disorders, or cyanamide therapy were reviewed. Half of the patients had history of organ transplantation and/or malignancy. These patients took on average 8.1 medications (range: 3-14) with the most common medications being immunosuppressive and health supplements. Histologically, GG hepatocytes show either peri-portal or centrizonal distribution. The inclusions are PAS-positive and diastase sensitive. Electron microscopy showed intracytoplasmic granular inclusions with low electron density, consistent with unstructured glycogen. In summary, GG hepatocytes are a rare finding in liver biopsies, but are more common in patients with hepatitis B. They can also be seen in HBV-negative patients who have polypharmacy. In these cases, they are the result of unstructured glycogen accumulation putatively due to altered cell metabolism.

Topics: Adult; Aged; Biopsy; Carcinoma, Hepatocellular; Chemical and Drug Induced Liver Injury; Child, Preschool; Cyanamide; Cytoplasm; Dietary Supplements; Female; Glycogen; Glycogen Storage Disease; Hepatitis B, Chronic; Hepatocytes; Humans; Immunosuppressive Agents; Inclusion Bodies; Liver; Liver Neoplasms; Male; Microscopy, Electron; Middle Aged; Polypharmacy

Chronic hepatitises of various etiologies are widespread liver diseases in humans. Their final stage, liver cirrhosis (LC), is considered to be one of the main causes of hepatocellular carcinoma (HCC). About 80-90% of all HCC cases develop in LC patients, which suggests that cirrhotic conditions play a crucial role in the process of hepatocarcinogenesis. Carbohydrate metabolism in LC undergoes profound disturbances characterized by altered glycogen metabolism. Unfortunately, data on the glycogen content in LC are few and contradictory. In this study, the material was obtained from liver biopsies of patients with LC of viral and alcohol etiology and from the liver tissue of rats with CCl

Topics: Animals; Carcinoma, Hepatocellular; Child; Glycogen; Hepatocytes; Humans; Liver Cirrhosis; Liver Neoplasms; Male; Rats

Dendritic macromolecules are potential candidates for nanomedical application. Herein, glycogen, the natural hyperbranched polysaccharide with favorable biocompatibility, is explored as an effective drug vehicle for treating liver cancer. In this system, glycogen is oxidized and conjugated with cancer drugs through a disulfide link, followed by

Topics: Animals; Antineoplastic Agents; Carcinoma, Hepatocellular; Cell Line, Tumor; Combined Modality Therapy; Doxorubicin; Drug Liberation; Glycogen; Hemolysis; Humans; Hyperthermia, Induced; Infrared Rays; Liver Neoplasms; Mice, Inbred BALB C; Nanoparticles; Phospholipids; Photochemotherapy; Polymers; Pyrroles

Kinetic modeling and control analysis of a metabolic pathway may identify the steps with the highest control in tumor cells, and low control in normal cells, which can be proposed as the best therapeutic targets.. Enzyme kinetic characterization, pathway kinetic modeling and control analysis of the glucose central metabolism were carried out in rat (hepatoma AS-30D) and human (cervix HeLa) cancer cells and normal rat hepatocytes.. The glycogen metabolism enzymes in AS-30D, HeLa cells and hepatocytes showed similar kinetic properties, except for higher AS-30D glycogen phosphorylase (GP) sensitivity to AMP. Pathway modeling indicated that fluxes of glycogen degradation and PPP were mainly controlled by GP and NADPH consumption, respectively, in both hepatocytes and cancer cells. Likewise, hexose-6-phosphate isomerase (HPI) and phosphoglucomutase (PGM) exerted significant control on glycolysis and glycogen synthesis fluxes in cancer cells but not in hepatocytes. Modeling also indicated that glycolytic and glycogen synthesis fluxes could be strongly decreased when HPI and PGM were simultaneously inhibited in AS-30D cells but not in hepatocytes. Experimental assessment of these predictions showed that both the glycolytic and glycogen synthesis fluxes of AS-30D cells, but not of hepatocytes, were inhibited by oxamate, by inducing increased Fru1,6BP levels, a competitive inhibitor of HPI and PGM.. HPI and PGM seem suitable targets for decreasing glycolytic and glycogen synthesis fluxes in AS-30D cells but not in hepatocytes.. The present study identified new therapeutic targets within glucose central metabolism in the analyzed cancer cells, with no effects on non-cancer cells.

Topics: Animals; Carcinoma, Hepatocellular; Cell Line, Tumor; Cells, Cultured; Glucose; Glycogen; HeLa Cells; Hepatocytes; Humans; Kinetics; Liver Neoplasms; Male; Models, Biological; Rats, Wistar

Clear cell foci (CCF) of the liver are considered to be pre-neoplastic lesions of hepatocellular adenomas and carcinomas. They are hallmarked by glycogen overload and activation of AKT (v-akt murine thymoma viral oncogene homolog)/mTOR (mammalian target of rapamycin)-signaling. Here, we report the transcriptome and proteome of CCF extracted from human liver biopsies by laser capture microdissection. We found 14 genes and 22 proteins differentially expressed in CCF and the majority of these were expressed at lower levels in CCF. Using immunohistochemistry, the reduced expressions of STBD1 (starch-binding domain-containing protein 1), USP28 (ubiquitin-specific peptidase 28), monad/WDR92 (WD repeat domain 92), CYB5B (Cytochrome b5 type B), and HSPE1 (10 kDa heat shock protein, mitochondrial) were validated in CCF in independent specimens. Knockout of

Topics: Biomarkers, Tumor; Cell Transformation, Neoplastic; Computational Biology; Gene Expression Profiling; Glycogen; Humans; Immunohistochemistry; Liver Diseases; Liver Neoplasms; Proteomics; Transcriptome

Glycogen phosphorylase kinase β-subunit (PHKB) is a regulatory subunit of phosphorylase kinase (PHK), involving in the activation of glycogen phosphorylase (GP) and the regulation of glycogen breakdown. Emerging evidence suggests that PHKB plays a role in tumor progression. However, the function of PHKB in HCC progression remains elusive. Here, our study revealed that the expression of PHKB significantly decreased in HCC tissues, and the low expression of PHKB could serve as an independent indicator for predicting poor prognosis in HCC. Functional experiments showed that PHKB knockdown significantly promoted cell proliferation both

Topics: Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Epithelial-Mesenchymal Transition; Gene Knockdown Techniques; Glycogen; Humans; Liver Neoplasms; Phosphorylase Kinase; Prognosis; Protein Subunits; Proto-Oncogene Proteins c-akt; Signal Transduction; STAT3 Transcription Factor

Topics: Adult; Diabetes Complications; Diagnosis, Differential; Diffusion Magnetic Resonance Imaging; Glycogen; Glycogen Storage Disease Type I; Hepatomegaly; Humans; Liver; Liver Diseases; Liver Neoplasms; Male; Tomography, X-Ray Computed

Portal hypertension is the primary cause of complications in patients with chronic liver diseases, and markedly impacts metabolism within the nervous system. Until recently, the role of portal hypertension in hepatocellular metabolism was unclear. The present study demonstrated that an increase in extracellular pressure significantly decreased hepatocellular glycogen concentrations in HepG2 and HL‑7702 cells. In addition, it reduced glycogen synthase activity, by inhibiting the phosphorylation of glycogen synthase 1. RNA‑seq analysis revealed that mechanical pressure suppressed glycogen synthesis by activating the p53/phosphatase and tensin homolog pathway, further suppressing glycogen synthase activity. The present study revealed an association between mechanical pressure and hepatocellular glycogen metabolism, and identified the regulatory mechanism of glycogen synthesis under pressure.

Topics: Carcinoma, Hepatocellular; Cell Line, Tumor; Glycogen; Glycogen Synthase; Humans; Liver Neoplasms; Phosphorylation; Pressure; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Signal Transduction; Tumor Suppressor Protein p53

Hepatocellular carcinoma (HCC) is one of the leading cancers in the world in incidence and mortality. Current pharmacotherapy of HCC is limited in the number and efficacy of anticancer agents. Metabolic reprogramming is a prominent feature of many cancers and has rekindled interest in targeting metabolic proteins for cancer therapy. Glycogen is a storage form of glucose, and the levels of glycogen have been found to correlate with biological processes in reprogrammed cancer cells. However, the contribution of glycogen metabolism to carcinogenesis, cancer cell growth, metastasis, and chemoresistance is poorly understood. Thus, we studied the processes involved in the inhibition of glycogen metabolism in HCC cells. Pharmacological inhibition of glycogen phosphorylase (GP), a rate-limiting enzyme in glycogen catabolism, by CP-91149 led to a decrease in HCC cell viability. GP inhibition induced cancer cell death through the intrinsic apoptotic pathway. Mitochondrial dysfunction and autophagic adaptations accompanied this apoptosis process whereas endoplasmic reticulum stress, necrosis, and necroptosis were not major components of the cell death. In addition, GP inhibition potentiated the effects of multikinase inhibitors sorafenib and regorafenib, which are key drugs in advanced-stage HCC therapy. Our study provides mechanistic insights into cell death by perturbation of glycogen metabolism and identifies GP inhibition as a potential HCC pharmacotherapy target.

Topics: Amides; Animals; Apoptosis; Carcinoma, Hepatocellular; Cell Line, Tumor; Drug Resistance, Neoplasm; Drug Synergism; Energy Metabolism; Glycogen; Glycogen Phosphorylase; Hep G2 Cells; Humans; Indoles; Liver Neoplasms; Phenylurea Compounds; Protein Kinase Inhibitors; Pyridines; Rats; Sorafenib

In hepatocellular carcinoma (HCC), the regulatory protease Dipeptidyl-peptidase IV (DPPIV/CD26), that possesses pro-apoptotic properties, has been found abnormally regulated. The protease inhibitor SerpinB3, exerting anti-apoptotic activity, has also been described to be upregulated, especially in HCCs with poor prognosis. The aim of this study was to investigate the possible relationship between these two molecules in HCC patients and in experimental models.. DPPIV/CD26 and SerpinB3 expression was measured in liver specimens of 67 patients with HCC. HepG2 and Huh7 cells, stably transfected to overexpress SerpinB3, and respective control cells were used to assess biological and metabolic modifications of DPPIV/CD26 activity induced by this serpin.. DPPIV/CD26 and SerpinB3 were localized in the same tumoral areas and both molecules were correlated with the grade of tumor differentiation, with the highest values detected in GI tumors. Cell lines over-expressing SerpinB3 displayed upregulation of DPPIV/CD26, likely as a feedback mechanism, due to the DPPIV/CD26 protease activity inhibition by SerpinB3, as confirmed by the similar behavior induced by the inhibitor Sitagliptin. Moreover, they exhibited lower glycogen storage and higher lipid accumulation, typical effects of DPPIV/CD26.. A close connection between SerpinB3 and DPPPIV has been identified, but further studies are required to better understand the mechanism by which these proteins communicate and exert metabolic effects in HCC.

Topics: Aged; Antigens, Neoplasm; Carcinoma, Hepatocellular; Dipeptidyl Peptidase 4; Female; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Glycogen; Hep G2 Cells; Humans; Lipid Metabolism; Liver Neoplasms; Male; Middle Aged; Neoplasm Proteins; Serpins; Sitagliptin Phosphate

Both Pten and Nras are downstream mediators of receptor tyrosine kinase activation that plays important roles in controlling cell survival and proliferation. Here, we investigated whether and how Pten loss cross-talks with Nras activation in driving liver cancer development in mice. Somatic disruption of hepatic Pten and overexpression of Nras were achieved in out-bred immunocompetent CD-1 mice through a hydrodynamic delivery of plasmids carrying Sleeping Beauty transposon-based integration of Nras and the CRISPR/Cas9-mediated Pten knockout system. Concurrent Pten knockout and Nras knock-in induced hepatocellular carcinoma, while individual gene manipulation failed. Tumor development was associated with liver fibrosis, hyperlipidemia, hepatic deposition of lipid droplets and glycogen, and hepatomegaly. At the molecular level, lipid droplet formation was primarily contributed by upregulated expression of genes responsible for lipogenesis and fatty acid sequestration, such as Srebpf1, Acc, Pparg and its downstream targets. Our findings demonstrated that Pten disruption was synergized by Nras overexpression in driving hepatocyte malignant transformation, which correlated with extensive formation of lipid droplets.

Topics: Animals; Carcinoma, Hepatocellular; CRISPR-Cas Systems; Energy Metabolism; Gene Expression; Gene Knock-In Techniques; Gene Knockout Techniques; Gene Order; Gene Transfer Techniques; Genetic Vectors; Glycogen; GTP Phosphohydrolases; Immunohistochemistry; Lipid Metabolism; Liver Neoplasms; Male; Membrane Proteins; Mice; Mice, Knockout; Mice, Transgenic; PTEN Phosphohydrolase; Signal Transduction

One of the important functions of the liver is glycogen storage. Most processes associated with increased hepatic glycogen, or glycogenoses, are metabolic and affect the entire liver leading to diffuse glycogenosis. We present a case in which the liver contained multiple small pale nodules that on initial assessment were recognized to be composed of glycogenated hepatocytes. Most of the known causes of hepatic glycogenosis were not pertinent to this case. After cutting many deeper levels and obtaining additional sections, small foci of insulinoma were revealed in the center of each of these lesions. The glycogenosis surrounding the foci of insulinoma can be best explained as a local effect of insulin on the hepatocytes, a phenomenon that has been previously described in primate models, but not in human subjects. Here, we report the first case of metastatic insulinoma causing local hepatic glycogenosis.

Topics: Adult; Female; Glycogen; Glycogen Storage Disease; Hepatocytes; Humans; Insulinoma; Liver; Liver Neoplasms; Male; Neoplasm Metastasis; Pancreatic Neoplasms

Hepatitis B virus (HBV) pre-S2 mutant can induce hepatocellular carcinoma (HCC) via the induction of endoplasmic reticulum stress to activate mammalian target of rapamycin (MTOR) signaling. The association of metabolic syndrome with HBV-related HCC raises the possibility that pre-S2 mutant-induced MTOR activation may drive the development of metabolic disorders to promote tumorigenesis in chronic HBV infection. To address this issue, glucose metabolism and gene expression profiles were analyzed in transgenic mice livers harboring pre-S2 mutant and in an in vitro culture system. The pre-S2 mutant transgenic HCCs showed glycogen depletion. The pre-S2 mutant initiated an MTOR-dependent glycolytic pathway, involving the eukaryotic translation initiation factor 4E binding protein 1 (EIF4EBP1), Yin Yang 1 (YY1), and myelocytomatosis oncogene (MYC) to activate the solute carrier family 2 (facilitated glucose transporter), member 1 (SLC2A1), contributing to aberrant glucose uptake and lactate production at the advanced stage of pre-S2 mutant transgenic tumorigenesis. Such a glycolysis-associated MTOR signal cascade was validated in human HBV-related HCC tissues and shown to mediate the inhibitory effect of a model of combined resveratrol and silymarin product on tumor growth. Our results provide the mechanism of pre-S2 mutant-induced MTOR activation in the metabolic switch in HBV tumorigenesis. Chemoprevention can be designed along this line to prevent HCC development in high-risk HBV carriers.

Topics: Adaptor Proteins, Signal Transducing; Animals; Carcinoma, Hepatocellular; Cell Cycle Proteins; Cell Line; Glucose Transporter Type 1; Glycogen; Glycolysis; Hepatitis B; Hepatitis B Surface Antigens; Hepatitis B virus; Humans; Immunohistochemistry; Liver Neoplasms; Mice; Mice, Transgenic; Mutant Proteins; Phosphoproteins; Protein Precursors; Proto-Oncogene Proteins c-myc; Signal Transduction; TOR Serine-Threonine Kinases; YY1 Transcription Factor

Protein targeting to glycogen (PTG) is a ubiquitously expressed scaffolding protein that critically regulates glycogen levels in many tissues, including the liver, muscle and brain. However, its importance in transformed cells has yet to be explored in detail. Since recent studies have demonstrated an important role for glycogen metabolism in cancer cells, we decided to assess the effect of PTG levels on the ability of human hepatocellular carcinoma (HepG2) cells to respond to metabolic stress. Although PTG expression did not significantly affect the proliferation of HepG2 cells under normal culture conditions, we determined that PTG plays an important role during glucose deprivation. Overexpression of PTG protected cells from cell death in the absence of glucose, whereas knocking down PTG further promoted cytotoxicity, as measured by the release of lactate dehydrogenase (LDH) into the media. Additionally, we demonstrated that PTG attenuates glucose deprivation induced haeme oxygenase-1 (HO-1) expression, suggesting that PTG protects against glucose deprivation-induced oxidative stress. Indeed, treating cells with the antioxidant N-acetyl cysteine (NAC) rescued cells from cytotoxicity caused by glucose deprivation. Finally, we showed that loss of PTG resulted in enhanced autophagy. In control cells, glucose deprivation suppressed autophagy as determined by the increase in the levels of p62, an autophagy substrate. However, in knockdown cells, this suppression was relieved. Blockade of autophagy also attenuated cytotoxicity from glucose deprivation in PTG knockdown cells. Taken together, our findings identify a novel role for PTG in protecting hepatocellular carcinoma cells from metabolic stress, in part by regulating oxidative stress and autophagy.

Topics: Autophagy; Carcinoma, Hepatocellular; Carrier Proteins; Cell Death; DNA-Binding Proteins; Gene Knockdown Techniques; Glucose; Glycogen; Glycogen Debranching Enzyme System; Heme Oxygenase-1; Hep G2 Cells; Humans; Intracellular Signaling Peptides and Proteins; Liver Neoplasms; Oxidative Stress; Phosphoprotein Phosphatases; Transcription Factors

Hepatoma cell lines are frequently used as in vitro alternatives to primary human hepatocytes. Cell lines are characterized by their unlimited life span, stable phenotype, high availability, and easy handling. However, their major limitation is the lower expression of some metabolic activities compared with hepatocytes. HepG2 is a human hepatoma that is most commonly used in drug metabolism and hepatotoxicity studies. HepG2 cells are nontumorigenic cells with high proliferation rates and an epithelial-like morphology that perform many differentiated hepatic functions. In this chapter, freezing, thawing, and subculturing procedures for HepG2 cells are described. We further provide protocols for evaluating lipid accumulation, glycogen storage, urea synthesis, and phase I and phase II drug metabolizing activities in HepG2 cells.

Topics: Carcinoma, Hepatocellular; Cell Culture Techniques; Cytochrome P-450 Enzyme System; Glutathione Transferase; Glycogen; Hep G2 Cells; Humans; Lipid Metabolism; Liver Neoplasms; Urea

Topics: Adrenal Gland Neoplasms; Animals; Carcinoma, Hepatocellular; Cell Nucleus; Cyprinidae; Female; Fish Diseases; Glycogen; Hepatocytes; Liver Neoplasms; Pheochromocytoma

Topics: Delayed Diagnosis; Dermatomyositis; Erythema; Facial Dermatoses; Fatal Outcome; Female; Glycogen; Humans; Liver Neoplasms; Middle Aged; Muscle, Skeletal; Ovarian Neoplasms; Paraneoplastic Syndromes; Photosensitivity Disorders

STBD1 (starch-binding domain-containing protein 1) belongs to the CBM20 (family 20 carbohydrate binding module) group of proteins, and is implicated in glycogen metabolism and autophagy. However, very little is known about its regulation or interacting partners. Here, we show that the CBM20 of STBD1 is crucial for its stability and ability to interact with glycogen-associated proteins. Mutation of a conserved tryptophan residue (W293) in this domain abolished the ability of STBD1 to bind to the carbohydrate amylose. Compared with the WT (wild-type) protein, this mutant exhibited rapid degradation that was rescued upon inhibition of the proteasome. Furthermore, STBD1 undergoes ubiquitination when expressed in COS cells, and requires the N-terminus for this process. In contrast, inhibition of autophagy did not significantly affect protein stability. In overexpression experiments, we discovered that STBD1 interacts with several glycogen-associated proteins, such as GS (glycogen synthase), GDE (glycogen debranching enzyme) and Laforin. Importantly, the W293 mutant of STBD1 was unable to do so, suggesting an additional role for the CBM20 domain in protein-protein interactions. In HepG2 hepatoma cells, overexpressed STBD1 could associate with endogenous GS. This binding increased during glycogenolysis, suggesting that glycogen is not required to bridge this interaction. Taken together, our results have uncovered new insights into the regulation and binding partners of STBD1.

Topics: Animals; Autophagy; Carbohydrates; Carcinoma, Hepatocellular; Cell Line; Cell Line, Tumor; Chlorocebus aethiops; COS Cells; Glycogen; Glycogenolysis; HEK293 Cells; HeLa Cells; Hep G2 Cells; Humans; Liver Neoplasms; Membrane Proteins; Mutation; Proteasome Endopeptidase Complex; Protein Interaction Domains and Motifs; Tryptophan; Ubiquitination

The KIAA1199 gene was first discovered to be associated with non-syndromic hearing loss. Recently, several reports have shown that the up-regulation of KIAA1199 is associated with cancer cell migration or invasion and a poor prognosis. These findings indicate that KIAA1199 may be a novel target for cancer therapy. Therefore, we explored in detail the function of KIAA1199 in cancer cells. In this study, we investigated the interaction of KIAA1199 protein with intracellular proteins in cancer cells. To this end, we expressed KIAA1199-MBP fusion protein and performed a pull-down assay. In addition, KIAA1199-overexpressing cancer cell lines were constructed using a retroviral vector and were used for further experiments. A pull-down analysis showed that the glycogen phosphorylase kinase β-subunit (PHKB) interacted with the C-terminal region of KIAA1199 protein. Furthermore, we observed the interaction of KIAA1199 with glycogen phosphorylase brain form (PYGB) under serum-free conditions. The interaction promoted glycogen breakdown and cancer cell survival. Our findings indicate that KIAA1199 plays an important role in glycogen breakdown and cancer cell survival and that it may represent a novel target for cancer therapy.

Topics: Apoptosis; Cell Line, Tumor; Cell Survival; Glycogen; Humans; Hyaluronoglucosaminidase; Liver Neoplasms; Phosphorylase Kinase; Protein Subunits; Proteins; Stomach Neoplasms; Transfection; Up-Regulation

Hepatocarcinogenesis is a multistep process that starts from fatty liver and transitions to fibrosis and, finally, into cancer. Many etiological factors, including hepatitis B virus X antigen (HBx) and p53 mutations, have been implicated in hepatocarcinogenesis. However, potential synergistic effects between these two factors and the underlying mechanisms by which they promote hepatocarcinogenesis are still unclear. In this report, we show that the synergistic action of HBx and p53 mutation triggers progressive hepatocellular carcinoma (HCC) formation via src activation in zebrafish. Liver-specific expression of HBx in wild-type zebrafish caused steatosis, fibrosis and glycogen accumulation. However, the induction of tumorigenesis by HBx was only observed in p53 mutant fish and occurred in association with the up-regulation and activation of the src tyrosine kinase pathway. Furthermore, the overexpression of src in p53 mutant zebrafish also caused hyperplasia, HCC, and sarcomatoid HCC, which were accompanied by increased levels of the signaling proteins p-erk, p-akt, myc, jnk1 and vegf. Increased expression levels of lipogenic factors and the genes involved in lipid metabolism and glycogen storage were detected during the early stages of hepatocarcinogenesis in the HBx and src transgenic zebrafish. The up-regulation of genes involved in cell cycle regulation, tumor progression and other molecular hallmarks of human liver cancer were found at later stages in both HBx and src transgenic, p53 mutant zebrafish. Together, our study demonstrates that HBx and src overexpression induced hepatocarcinogenesis in p53 mutant zebrafish. This phenomenon mimics human HCC formation and provides potential in vivo platforms for drug screening for therapies for human liver cancer.

Topics: Animals; Animals, Genetically Modified; Apoptosis; Biomarkers, Tumor; Carcinogenesis; Carcinoma, Hepatocellular; Cell Cycle; CSK Tyrosine-Protein Kinase; Enzyme Activation; Fibrosis; Gene Expression; Glycogen; Humans; Hyperplasia; Lipogenesis; Liver; Liver Neoplasms; Mutation; Neoplasm Metastasis; Organ Specificity; Proliferating Cell Nuclear Antigen; Recombinant Fusion Proteins; Signal Transduction; src-Family Kinases; Trans-Activators; Tumor Suppressor Protein p53; Viral Regulatory and Accessory Proteins; Zebrafish

Topics: Aged; Biomarkers, Tumor; Biopsy, Needle; Carcinoma, Hepatocellular; Glucose-6-Phosphatase; Glycogen; Hepatocytes; Humans; Liver Neoplasms; Male; Phosphorylase b

Glycogenotic hepatocellular carcinoma (HCC) with glycogen-ground-glass hepatocytes has recently been described as an allegedly "novel variant" of HCC, but neither the historical background nor the heuristic relevance of this observation were put in perspective. In the present contribution, the most important findings in animal models and human beings related to the emergence and further evolution of excessively glycogen storing (glycogenotic) hepatocytes with and without ground glass features during neoplastic development have been summarized. Glycogenotic HCCs with glycogen-ground-glass hepatocytes represent highly differentiated neoplasms which contain subpopulations of cells phenotypically resembling those of certain types of preneoplastic hepatic foci and benign hepatocellular neoplasms. It is questionable whether the occurrence of glycogen-ground-glass hepatocytes in a glycogenotic HCC justifies its classification as a specific entity. The typical appearance of ground-glass hepatocytes is due to a hypertrophy of the smooth endoplasmic reticulum, which is usually associated with an excessive storage of glycogen and frequently also with an expression of the hepatitis B surface antigen. Sequential studies in animal models and observations in humans indicate that glycogen-ground-glass hepatocytes are a facultative, integral part of a characteristic cellular sequence commencing with focal hepatic glycogenosis potentially progressing to benign and malignant neoplasms. During this process highly differentiated glycogenotic cells including ground-glass hepatocytes are gradually transformed via various intermediate stages into poorly differentiated glycogen-poor, basophilic (ribosome-rich) cancer cells. Histochemical, microbiochemical, and molecular biochemical studies on focal hepatic glycogenosis and advanced preneoplastic and neoplastic lesions in tissue sections and laser-dissected specimens in rat and mouse models have provided compelling evidence for an early insulinomimetic effect of oncogenic agents, which is followed by a fundamental metabolic switch from gluconeogenesis towards the pentose-phosphate pathway and the Warburg type of glycolysis during progression from preneoplastic hepatic glycogenosis to the highly proliferative malignant phenotype.

Topics: Animals; Carcinoma, Hepatocellular; Cell Differentiation; Cell Shape; Disease Models, Animal; Disease Progression; Endoplasmic Reticulum; Glycogen; Glycogen Storage Disease; Hepatocytes; Humans; Liver Neoplasms; Mice; Phenotype; Precancerous Conditions; Rats

Proton magnetic resonance spectroscopy (MRS) of the liver in vivo is in experimental phase. MRS observation on liver cancer after transcatheter arterial chemoembolization (TACE) has seldom been reported. This study was to investigate the value of MRS in assessing the metabolic changes of hepatocellular carcinoma (HCC) after TACE.. Twenty-five consecutive patients with pathologically-confirmed HCC received 1H MRS of all hepatic lesions using 1.5T whole body MR scanner before TACE and at 3-10 days after TACE. Choline-to-lipid (Cho/Lip), glucogen/glucose-to-lipid (Glu/Lip), and glytamine/glutamate-to-lipid (Glx/Lip) ratios were measured and analyzed statistically.. The Cho/Lip, Glu/Lip, and Glx/Lip ratios were 0.21 +/- 0.08, 0.11 +/- 0.05, 0.28 +/- 0.10 before TACE, respectively, and were 0.10 +/- 0.08, 0.07 +/- 0.07, 0.18 +/- 0.12 after TACE, respectively, with significant differences (P < 0.05).. Using MRS can evaluate the early metabolic responses of HCC to TACE.

Topics: Adult; Aged; Carcinoma, Hepatocellular; Chemoembolization, Therapeutic; Choline; Female; Glucose; Glutamic Acid; Glutamine; Glycogen; Humans; Lipids; Liver Neoplasms; Magnetic Resonance Spectroscopy; Male; Middle Aged

To evaluate Bcl-xL, Bax, PCNA, cytokeratin 19 (CK-19), glycogen content and DNA ploidy expression in hepatoblastoma (HB) and their prognostic value.. This retrospective study on 26 cases of HB involved DNA ploidy estimations separately for various subtypes on histological sections using image cytometry of Feulgen-stained smears. Glycogen content, PCNA, CK-19, Bax and Bcl-xL expression on tissue sections were evaluated. THE outcome on follow-up (mean 86 months) and Kaplan-Meier survival analysis were performed.. Fetal areas were diploid (84%); embryonal areas were aneuploid (89.47%) (p < 0.001). PCNA labeling index was low in fetal (10.82%) and high in embryonal areas (59.85%) (p = 0.03). CK-19 was negative in fetal, but focally positive in embryonal areas. Bax was negative in fetal (80%) and positive in embryonal areas (88.23%) (p < 0.001); Bcl-xL was more frequently positive in fetal (90%) than embryonal areas (52.94%) (p = 0.02). Fetal cells were rich in glycogen. Kaplan-Meier survival analysis showed good initial radiological response to chemotherapy (p = 0.009), glycogen content (p = 0.0137) and DNA diploid cases (p = 0.0429) were associated with good outcome on univariate analysis. Histology typing (p = 0.085), Bcl-xL (p = 0.689), Bax (p = 0.27), CK-19 (p = 0.281), PCNA (p = 0.689), age (p = 0.24), sex (p = 0.5661), stage (p = 0.24) and α-fetoprotein levels (p = 0.49) were unrelated to outcome. Multivariate analysis showed glycogen content to be the most statistically significant variable (0.024).. Fetal and embryonal areas show different staining patterns for PCNA, Bax and Bcl-xL. DNA ploidy and glycogen content are significant prognostic variables.

Topics: Adolescent; bcl-2-Associated X Protein; bcl-X Protein; Biomarkers, Tumor; Cell Proliferation; Child; Child, Preschool; Female; Glycogen; Hepatoblastoma; Humans; Infant; Keratin-19; Liver Neoplasms; Male; Multivariate Analysis; Periodic Acid-Schiff Reaction; Ploidies; Prognosis; Proliferating Cell Nuclear Antigen; Proportional Hazards Models; Retrospective Studies; Survival Analysis

Resistin is a 12.5-KDa cysteine-rich peptide that has been implicated in the impairment of glucose homeostasis via the AMP-activated protein kinase (AMPK) pathway in a rodent model. However, the role resistin plays in humans is controversial. This study investigated the effect of resistin on glucose metabolism and insulin signaling using human recombinant resistin and small interfering RNA (siRNA) against AMPKalpha2 to treat the human liver HepG2 cells. The mRNA of key genes involved in glucose metabolism and the insulin-signaling pathway were detected by real-time RT-PCR. Phosphorylation levels of Akt and AMPK were measured by western blot. The incorporation of D-[U-(14)C] glucose into glycogen was quantitated by liquid scintillation counting. The results demonstrate that resistin stimulated expressions of glucose-6-phosphatase (G6Pase), phosphoenolypyruvate carboxykinase (PEPCK), and suppressor of cytokine signaling 3 (SOCS-3), repressed the expressions of insulin receptor substrate 2(IRS-2) and glucose transporter 2(GLUT2). In addition, resistin inhibited the insulin-induced phosphorylation of Akt independent of AMPK. In conclusion, our findings suggest that resistin induces insulin resistance in HepG2 cells at least partly via induction of SOCS-3 expression and reduction of Akt phosphorylation through an AMPK-independent mechanism. Resistin also increases glucose production via AMPK-mediated upregulated expression of the genes encoding hepatic gluconeogenic enzymes, G6Pase, and PEPCK.

Topics: AMP-Activated Protein Kinases; Carcinoma, Hepatocellular; Cell Line, Tumor; Gene Expression; Glucaric Acid; Glucose Transporter Type 2; Glucose-6-Phosphatase; Glycogen; Humans; Hypoglycemic Agents; Insulin; Insulin Receptor Substrate Proteins; Insulin Resistance; Liver Neoplasms; Phosphoenolpyruvate Carboxykinase (GTP); Phosphorylation; Proto-Oncogene Proteins c-akt; Resistin; RNA, Small Interfering; Signal Transduction; Suppressor of Cytokine Signaling 3 Protein; Suppressor of Cytokine Signaling Proteins

The Hepatitis B virus X (HBx) protein has been strongly implicated in the carcinogenesis of hepatocellular carcinoma (HCC). However, effects of the HBx protein on cell proliferation and cell death are controversial. This study investigates the effects of the HBx protein on liver regeneration in two independent lines of HBx transgenic mice, which developed HCC at around 14 to 16 months of age. High mortality, lower liver mass restoration, and impaired liver regeneration were found in the HBx transgenic mice post-hepatectomy. The levels of alanine aminotransferase and alpha-fetoprotein detected post-hepatectomy increased significantly in the HBx transgenic livers, indicating that they were more susceptible to damage during the regenerative process. Prolonged activation of the immediate-early genes in the HBx transgenic livers suggested that the HBx protein creates a strong effect by promoting the transition of the quiescent hepatocytes from G0 to G1 phase. However, impaired DNA synthesis and mitosis, as well as inhibited activation of G1, S, and G2/M markers, were detected. These results indicated that HBx protein exerted strong growth arrest on hepatocytes and imbalanced cell-cycle progression resulting in the abnormal cell death; this was accompanied by severe fat accumulation and impaired glycogen storage in the HBx transgenic livers. In conclusion, this study provides the first physiological evidence that HBx protein blocks G1/S transition of the hepatocyte cell-cycle progression and causes both a failure of liver functionality and cell death in the regenerating liver of the HBx transgenic mice.

Topics: Alanine Transaminase; alpha-Fetoproteins; Animals; Bromodeoxyuridine; Cell Cycle; Cell Death; Cell Proliferation; DNA; G1 Phase; Glycogen; Hepatocytes; Immunohistochemistry; Liver; Liver Neoplasms; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mitochondria; Mitosis; Models, Genetic; Models, Statistical; Regeneration; Resting Phase, Cell Cycle; Reverse Transcriptase Polymerase Chain Reaction; RNA; S Phase; Time Factors; Tissue Distribution; Trans-Activators; Viral Regulatory and Accessory Proteins

Previous studies from our laboratory have shown that vanadium stabilizes xenobiotic metabolizing enzymes and antioxidant status and suppresses DNA-protein crosslinks during chemically-induced hepatocarcinogenesis in rats. In the present study, we have further investigated the in vivo antitumor potential of this micronutrient by determining the effect of 0.5 ppm vanadium in drinking water on biomarkers for the early stages of hepatocarcinogenesis; the biomarkers included gamma-glutamyl transpeptidase (GGT)-positive foci and glycogen-storage foci, in situ expression of proliferating cell nuclear antigen (PCNA), and genotoxic DNA damage assessed by the alkaline Comet assay. Histomorphometry also was assessed during the study. Hepatocarcinogenesis was induced by treating 4-week-old male Sprague-Dawley rats with a single, necrogenic, intraperitoneal (i.p.) injection of 200 mg/kg body weight diethylnitrosamine (DEN). Compared to the carcinogen control, vanadium administration over the 32 weeks of the experiment reduced the relative liver weight by 30%, the incidence of nodules by 69.34%, the total number and multiplicity of nodules by 80.77%, and remodeled the hepatocellular premalignant architecture towards a normal phenotype. Moreover, long-term vanadium treatment reduced the development of GGT foci by 76.2% (P < 0.001), decreased periodic acid-Schiff's reactivity by 59.49% (P < 0.01), and decreased PCNA expression, with the concomitant reduction in PCNA immunolabeling index by 93.36% (P < 0.001). Finally, vanadium inhibited early DNA damage (DNA strand-breaks) in DEN-treated rat hepatocytes as expressed in the Comet assay by a 60.04% reduction in the length:width value of DNA mass (P < 0.01) and a 51.54% reduction in the tail length of the DNA comets (P < 0.001). Our results indicate that continuous supplementation with 0.5 ppm vanadium suppresses hepatocellular neoplastic transformation in rats.

Topics: Animals; Anticarcinogenic Agents; Body Weight; Diethylnitrosamine; DNA Damage; gamma-Glutamyltransferase; Glycogen; Liver; Liver Neoplasms; Male; Organ Size; Precancerous Conditions; Proliferating Cell Nuclear Antigen; Rats; Rats, Sprague-Dawley; Vanadium

Dichloroacetic acid (DCA) is a liver carcinogen that induces DNA hypomethylation in mouse liver. To test the involvement of DNA hypomethylation in the carcinogenic activity of DCA, we determined the effect of methionine on both activities. Female B6C3F1 mice were administered 3.2 g/l DCA in their drinking water and 0, 4.0, and 8.0 g/kg methionine in their diet. Mice were sacrificed after 8 and 44 weeks of exposure. After 8 weeks of exposure, DCA increased the liver/body weight ratio and caused DNA hypomethylation, glycogen accumulation, and peroxisome proliferation. Methionine prevented completely the DNA hypomethylation, reduced by only 25% the glycogen accumulation, and did not alter the increased liver/body weight ratio and the proliferation of peroxisomes induced by DCA. After 44 weeks of exposure, DCA induced foci of altered hepatocytes and hepatocellular adenomas. The multiplicity of foci of altered hepatocytes/mouse was increased from 2.41 +/- 0.38 to 3.40 +/- 0.46 by 4.0 g/kg methionine and decreased to 0.94 +/- 0.24 by 8.0 g/kg methionine, suggesting that methionine slowed the progression of foci to tumors. The low and high concentrations of methionine reduced the multiplicity of liver tumors/mouse from 1.28 +/- 0.31 to 0.167 +/- 0.093 and 0.028 +/- 0.028 (i.e., by 87 and 98%, respectively). Thus, the prevention of liver tumors by methionine was associated with its prevention of DNA hypomethylation, indicating that DNA hypomethylation was critical for the carcinogenic activity of DCA.

Topics: Adenoma, Liver Cell; Animals; Chlorine; Dichloroacetic Acid; DNA Methylation; Drug Combinations; Female; Glycogen; Hepatocytes; Liver Neoplasms; Methionine; Mice; Mice, Inbred Strains; Organ Size; Peroxisome Proliferators; Peroxisomes; Water Purification

The overabundance of dietary fats and simple carbohydrates contributes significantly to obesity and metabolic disorders associated with obesity. The liver balances glucose and lipid distribution, and disruption of this balance plays a key role in these metabolic syndromes. We investigated (1) how hepatocytes balance glucose and fatty acid metabolism when one or both nutrients are supplied in abundance and (2) whether rat hepatoma cells (McA-RH7777) reflect nutrient partitioning in a similar manner as compared with primary hepatocytes. Increasing media palmitate concentration increased fatty acid uptake, triglyceride synthesis and beta-oxidation. However, hepatoma cells had a 2-fold higher fatty acid uptake and a 2-fold lower fatty acid oxidation as compared with primary hepatocytes. McA-RH7777 cells did not synthesize significant amounts of glycogen and preferentially metabolized the glucose into lipids or into oxidation. In primary hepatocytes, the glucose was mostly spared from oxidation and instead partitioned into both de novo glycogen and lipid synthesis. Overall, lipid production was rapidly induced in response to either glucose or fatty acid excess and this may be one of the earliest indicators of metabolic syndrome development associated with nutrient excess.

Topics: Animals; Biological Transport; Carcinoma, Hepatocellular; Cell Line, Tumor; Cells, Cultured; Fatty Acids; Female; Glucose; Glycogen; Hepatocytes; Liver Neoplasms; Oxidation-Reduction; Palmitic Acid; Rats; Rats, Sprague-Dawley

HIV protease inhibitor treatment is associated with insulin resistance. We have recently demonstrated that the HIV protease inhibitor indinavir influences initial insulin signaling steps in HepG2 cells. Here we investigated in the same cell model whether indinavir alters insulin-stimulated glycogen synthesis. Since an altered phosphotyrosine phosphatase activity could represent a mechanism by which insulin signaling is influenced, we also assessed potential indinavir effects on protein tyrosine phosphatase activity directed against tyrosine phosphorylated insulin receptor substrate-1. HepG2 cells were incubated for 48 h without or with indinavir (100 micro mol/l). Subsequently, the insulin-stimulated incorporation of 14C-glucose into glycogen was measured. In indinavir-treated cells the insulin effect on glycogen synthesis was reduced by 30 +/- 4.5 %. Dephosphorylation of immobilized tyrosine-phosphorylated insulin-receptor substrate-1 by the cell extracts was determined using a microwell plate-based method, and indinavir treatment did not alter this dephosphorylation. In conclusion, our data suggest that indinavir affects insulin-stimulation of glycogen synthesis in liver cells, and this may be related to the previously observed alterations in insulin signaling. Direct effects of indinavir on the GLUT4 transport system, that have been suggested from data in other cell systems, are unlikely in HepG2 cells that express no or almost no GLUT4 transport system. Finally, our data do not support the hypothesis that indinavir alters insulin signaling by influencing protein tyrosine phosphatase activity directed against insulin receptor substrate-1.

Topics: Carcinoma, Hepatocellular; Glucose; Glycogen; HIV Protease Inhibitors; Humans; Hypoglycemic Agents; Indinavir; Insulin; Liver; Liver Neoplasms; Protein Tyrosine Phosphatases; Stimulation, Chemical; Tumor Cells, Cultured

In the present study, the chemopreventive effect of the active metabolite of vitamin D, 1alpha,25-dihydroxyvitamin D(3) (VD(3)), against chemically-induced and diabetes-promoted rat liver carcinogenesis was investigated. Hepatocarcinogenesis was initiated with a single intraperitoneal (i.p.) injection of diethylnitrosamine (DEN) (125 mg kg(-1) body weight) at week 4 followed by promotion with streptozotocin (STZ) (65 mg kg(-1) body weight with a single i.p. injection) at week 7. With this basic experimental regimen, the effect of VD(3) (0.3 microg (0.1 ml)(-1) propylene glycol per os twice a week) was investigated with effect from 4 weeks prior to the exposure of DEN. The results showed that VD(3) supplementation throughout the experimental period reduced the incidence, total number and multiplicity and altered the size of visible persistent nodules (PNs) in DEN- or DEN + STZ-treated rats as compared with their respective controls. In these two groups, it also caused a significant decrease in the number (p < 0.002 and 0.001 respectively) and focal area (p < 0.05) of gamma-glutamyltranspeptidase (GGT)-positive hepatic foci. Moreover, continuous supplementation of VD(3) exhibits a protective effect in maintaining the normal cellular architecture of the hepatocytes in DEN- or DEN + STZ-treated rats. Our results thus strongly suggest that VD(3) is very effective in the inhibition of DEN-initiated and STZ-induced diabetes-promoted rat liver carcinogenesis.

Topics: Animals; Body Weight; Calcitriol; Cytoplasm; Diabetes Mellitus, Experimental; Diethylnitrosamine; Endoplasmic Reticulum; gamma-Glutamyltransferase; Glycogen; Hepatocytes; Liver; Liver Neoplasms; Male; Microscopy, Electron; Models, Genetic; Organ Size; Rats; Rats, Sprague-Dawley; Streptozocin; Time Factors

Hepatocellular carcinomas elicited in woodchucks by the woodchuck hepatitis virus (WHV) emerge gradually from parenchymal areas of minimal structural deviation via two predominant preneoplastic hepatocellular lineages, composed of either glycogenotic/basophilic or amphophilic/basophilic cell foci. In this study we analyzed WHV replication during neoplastic development in both lineages.. In minimal deviation areas, preneoplastic hepatocellular foci, and hepatocellular neoplasms, developing in 16 WHV-carriers 31-38 months after WHV-inoculation, the proportion of hepatocytes containing WHV replicative intermediates (as detected by in situ hybridization for WHV DNA) and immunoreactive for WHV core and surface antigens was assessed.. Appearance of WHV replicative intermediates and expression of antigens were limited to the cytoplasm of hepatocytes and were strongly correlated (P<0.0001), both showing high levels in minimal deviation areas, but markedly reduced amounts in all types of preneoplastic hepatic focus (P<0.0001), and in hepatocellular adenomas. Most hepatocellular carcinomas were negative for WHV replicative intermediates and antigens.. In both the glycogenotic-basophilic and the amphophilic-basophilic preneoplastic hepatocellular lineage, WHV replication and antigen expression gradually decrease early during the preneoplastic phase. The close correlation of these changes with metabolic aberrations characterizing preneoplastic hepatocellular lineages suggests that oncogenic effects mimicking insulin/glucagon imbalances may be responsible for the repression of hepadnaviral replication.

Topics: Adenoma, Liver Cell; Animals; Cell Lineage; DNA, Viral; Glycogen; Hepatitis B Antigens; Hepatitis B Virus, Woodchuck; Hepatitis B, Chronic; Hepatocytes; In Situ Hybridization; Liver Neoplasms; Marmota; Precancerous Conditions; Virus Replication

Insulin signaling is regulated by tyrosine phosphorylation of the signaling molecules, such as the insulin receptor and insulin receptor substrates (IRSs). Therefore, the balance between protein-tyrosine kinases and protein-tyrosine phosphatase activities is thought to be important in the modulation of insulin signaling in insulin-resistant states. We thus employed the adenovirus-mediated gene transfer technique, and we analyzed the effect of overexpression of a wild-type protein-tyrosine phosphatase-1B (PTP1B) on insulin signaling in both L6 myocytes and Fao cells. In both cells, PTP1B overexpression blocked insulin-stimulated tyrosine phosphorylation of the insulin receptor and IRS-1 by more than 70% and resulted in a significant inhibition of the association between IRS-1 and the p85 subunit of phosphatidylinositol 3-kinase and Akt phosphorylation as well as mitogen-activated protein kinase phosphorylation. Moreover, insulin-stimulated glycogen synthesis was also inhibited by PTP1B overexpression in both cells. These effects were specific for insulin signaling, because platelet-derived growth factor (PDGF)-stimulated PDGF receptor tyrosine phosphorylation and Akt phosphorylation were not inhibited by PTP1B overexpression. The present findings demonstrate that PTP1B negatively regulates insulin signaling in L6 and Fao cells, suggesting that PTP1B plays an important role in insulin resistance in muscle and liver.

Topics: Adenoviridae; Blotting, Western; Carcinoma, Hepatocellular; Cell Line; Gene Transfer Techniques; Glycogen; Glycogen Synthase; Humans; Insulin; Insulin Receptor Substrate Proteins; Insulin Resistance; Liver; Liver Neoplasms; Muscles; Myocardium; Phosphatidylinositol 3-Kinases; Phosphoproteins; Phosphorylation; Platelet-Derived Growth Factor; Protein Serine-Threonine Kinases; Protein Tyrosine Phosphatases; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Signal Transduction; Tumor Cells, Cultured

The BC2 cell line derived from the human hepatocarcinoma, HGB, undergoes a spontaneous sharp differentiation process in culture as it becomes confluent, remains stably differentiated for several weeks, and may return to proliferation thereafter under appropriate density conditions. The relevance of the line as an hepatic model has been evaluated. Cells synthesize a large number of plasma proteins, and rates of glycogen and urea synthesis increase with time of confluency and become sensitive to insulin, reflecting the process of differentiation. Differentiated BC2 cells express the most relevant cytochrome P-450 (CYP) isozyme activities (CYP1A1/2, 2A6, 2B6, 2C9, 2E1, and 3A4) and conjugating enzymes (glutathione S-transferase and UDP-glucuronyltransferase) and also respond to model inducers. Methylcholanthrene induced an increase in CYP1A1/2 enzyme activity (eightfold), phenobarbital induced CYP2B6 activity (1.7-fold), and dexamethasone induced CYP3A4 activity (fivefold). In parallel, expression of the most relevant liver-enriched transcription factors, HNF-4, HNF-1, C/EBP-alpha and C/EBP-beta mRNAs, was significantly increased in differentiated cultures. This increase was largest in HNF-1 and HNF-4, which supports the idea that a redifferentiation process towards the hepatic phenotype takes place. BC2 is an hepatic cell line that is able to express most hepatic functions, especially the drug-biotransformation function, far more efficiently than any previously described human hepatoma cell line.

Topics: Albumins; Ammonia; Biotransformation; Cell Count; Cell Differentiation; Cell Division; Cell Size; Cytochrome P-450 Enzyme System; DNA, Neoplasm; Enzyme Induction; Gene Expression Regulation, Neoplastic; Glutathione; Glycogen; Humans; Liver Neoplasms; Organ Specificity; RNA, Messenger; Transcription Factors; Tumor Cells, Cultured; Urea

A 22-year-old woman without predisposing liver disease developed focal hepatic glycogenosis and hepatocellular carcinoma after 6 years of azathioprine therapy for Crohn's disease. Hepatocellular carcinoma without cirrhosis has previously been described during immunosuppression, but this is the first report of disseminated focal hepatic glycogenosis after long-term azathioprine therapy.

Topics: Adult; Azathioprine; Carcinoma, Hepatocellular; Crohn Disease; Female; Glycogen; Humans; Immunosuppressive Agents; Liver; Liver Neoplasms; Liver Transplantation

Foci of altered hepatocytes (FAH) represent preneoplastic lesions, as shown in various animal models of hepatocarcinogenesis, but their significance in the human liver has not been established. The cellular composition, size distribution and proliferation kinetics of FAH in 163 explanted and resected human livers with or without hepatocellular carcinoma (HCC) and their possible association with small-cell change of hepatocytes (SCC) were therefore studied. FAH, including glycogen-storing foci, were found in 84 of 111 cirrhotic livers, demonstrating higher incidences in cases with (29/32) than in those without HCC (55/79). FAH were observed more frequently in HCC-free cirrhosis associated with hepatitis B or C virus or chronic alcoholic abuse (high-risk group) (37/47) than in that due to other causes (low-risk group) (12/21). MCF, predominant in cirrhotic livers of the high-risk group, were more proliferative, larger and more often involved in formation of nodules of altered hepatocytes (39.3%) than were GSF (8.5%). The results suggest that the FAH are preneoplastic lesions, MCF being more advanced than GSF. Oncocytic and amphophilic cell foci were also observed, but their significance remains to be clarified. Two types of SCC, namely diffuse and intrafocal SCC, were identified, but only intrafocal SCC was found to be related to increased proliferative activity and more frequent nodular transformation of the FAH involved, suggesting a close association with progression from FAH to HCC.

Topics: Adolescent; Adult; Aged; Carcinoma, Hepatocellular; Cell Division; Child; Child, Preschool; Female; Glycogen; Hepatitis; Humans; Immunohistochemistry; Infant; Liver Cirrhosis; Liver Diseases; Liver Neoplasms; Male; Middle Aged; Precancerous Conditions; Proliferating Cell Nuclear Antigen

The hexosamine biosynthesis pathway has been hypothesized to mediate some of the regulatory as well as the deleterious effects of glucose. We have stably overexpressed the cDNA for human glutamine:fructose-6-phosphate amidotransferase (GFA), the rate-limiting enzyme in the hexosamine biosynthesis pathway, in rat-1 fibroblasts. Two cell lines expressing the human RNA were selected by Northern analysis, and they exhibited 51-95% increases in GFA activity. Insulin-stimulated glycogen synthase (GS) activity and net glycogen synthesis were assayed, and GFA cells revealed decreased insulin sensitivity for both GS and net glycogen synthesis. The ED50 for insulin stimulation of GS was 2.45 +/- 0.4 nmol/l insulin in controls and 5.29 +/- 1.01 nmol/l in GFA cells (P < 0.005). For insulin-stimulated glycogen synthesis, the ED50 was 3.43 +/- 0.88 nmol/l in controls and 5.54 +/- 0.98 nmol/l in GFA cells (P < 0.005). There were no significant differences in maximally insulin-stimulated or total GS activities, insulin binding or receptor number, or glucose uptake between GFA and control cells. We also examined the effects of glucose on GS activity. GFA cells had a twofold increase in GS activity at low glucose (0.5 mmol/l) when compared with controls (P < 0.025). Both GFA and control cells had an approximately 75-80% decrease in GS activity as glucose concentration was increased from 0.5 to 20 mmol/l. This change in GS activity was not observed until after 12 h in culture. GFA cells were more sensitive to the effects of glucose.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Carcinoma, Hepatocellular; Cell Line; Fibroblasts; Gene Library; Glucosamine; Glucose; Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing); Glycogen; Glycogen Synthase; Humans; Insulin; Kinetics; Liver Neoplasms; Rats; Transfection

Fertilized turkey eggs were injected with N-nitrosomopholine (1-10 mg/egg) or urethane (0.1-10 mg/egg) prior to or during the first hours of incubation. Four days prior to hatching, the experiments were terminated and the livers of the embryos removed. The hepatocarcinogens induced focally arranged hepatocytes with morphological and metabolic changes that were similar to preneoplastic foci observed in rodent studies in vivo. Foci with enlarged cells and excessive storage of glycogen as well as basophilic foci with small cells, low in glycogen content and with frequent mitotic figures were found. The in ovo transformation of embryonal hepatocytes may be a promising rapid model of hepatocarcinogenesis.

Topics: Animals; Glucosephosphate Dehydrogenase; Glycogen; Liver; Liver Neoplasms; Nitrosamines; Precancerous Conditions; Turkeys; Urethane

Five mutants of recombinant insulin-like growth factor-II (rIGF-II) that bound with high affinity to either the IGF-II/cation-independent mannose 6-phosphate (IGF-II/CIM6-P) or the IGF-I receptor were prepared by site-directed mutagenic procedures, expressed as fusion proteins in the larva of Bombyx mori or Escherichia coli, purified to homogeneity, renatured, and characterized in terms of their receptor binding affinities and specificities as well as their biological activities. Class I mutants in which Phe26, Tyr27, and Val43 were substituted with Ser, Leu, and Leu, respectively, bound to enriched preparations of rat placental IGF-II/CIM6-P receptors with apparent equilibrium dissociation constants (Kd(app)) that were only slightly greater, i.e. 0.10, 0.05, and 0.06 nM, than that of rIGF-II (0.04 nM) or hIGF-II (0.03 nM). In contrast, replacing Phe26 with Ser resulted in 5- and 20-fold decreases in the affinities of this mutant for highly purified human placental IGF-I and insulin receptors, respectively. The affinities of the two other Class I mutants, [Leu27]- and [Leu43]rIGF-IIs, for these two receptors were reduced 80- to 220-fold. The affinities of Class II mutants, i.e. [Thr48,Ser49,Ile50]- and [Arg54,Arg55] rIGF-IIs, for IGF-I receptors were as potent as rIGF-II; however, they bound very poorly or not at all to the IGF-II/CIM6-P receptor. In the binding study of those mutant rIGF-IIs, IGF-II was observed to have an unexpectedly high affinity for pure human placental insulin receptor preparations. For example, the affinities of hIGF-II, rIGF-II, and two Class II rIGF-II mutants for the insulin receptor were only 3-, 9-, and 5-fold less, respectively, than that of porcine insulin. In two biological assay systems, i.e. the stimulation of DNA synthesis in Balb/c 3T3 cells and glycogen synthesis in HepG2 cells, the Kd(app) of the rIGF-II mutants for the IGF-I receptor but not the IGF-II/CIM6-P receptor correlated with their abilities to produce biological responses.

Topics: 3T3 Cells; Amino Acid Sequence; Animals; Base Sequence; Carcinoma, Hepatocellular; Chromatography, High Pressure Liquid; Cloning, Molecular; Disulfides; DNA; DNA Mutational Analysis; Genetic Vectors; Glycogen; Humans; In Vitro Techniques; Insulin; Insulin-Like Growth Factor II; Ligands; Liver Neoplasms; Mice; Molecular Sequence Data; Oligonucleotides; Peptide Mapping; Protein Binding; Protein Conformation; Receptor, IGF Type 2; Receptor, Insulin; Receptors, Cell Surface; Receptors, Somatomedin; Recombinant Proteins; Structure-Activity Relationship; Tumor Cells, Cultured

The effect of the glucose analogue N-hydroxyethyl-1-deoxynojirimycin (BAY m 1099) on the activity of alpha-glucosidases was studied in human fibroblasts and HepG2 cells. BAY m 1099 inhibits neutral and acid alpha-glucosidase activities of both cell types in a dosage-dependent and reversible manner. Inhibition of endoplasmic reticulum glucosidases I and/or II is suggested by delayed processing of lysosomal (acid) alpha-glucosidase. Competitive inhibition of mature acid alpha-glucosidase leads to lysosomal accumulation of glycogen as in glycogenosis type II. There seems to be little risk, however, of inducing this storage disorder when using the drug in a dose of 50 mg per os for treatment of type II diabetes. In high doses, the drug may prove useful for studying the pathogenesis of glycogenosis type II in vitro or in animal models.

Topics: 1-Deoxynojirimycin; alpha-Glucosidases; Binding, Competitive; Carcinoma, Hepatocellular; Fibroblasts; Glucosamine; Glycogen; Glycoside Hydrolase Inhibitors; Humans; Imino Pyranoses; Immunohistochemistry; Kinetics; Liver Neoplasms; Lysosomes; Microscopy, Electron; Molecular Weight; Tumor Cells, Cultured

In the palliative treatment of liver malignancy, hepatic dearterialization is being increasingly used. To study the metabolic consequences of this treatment, the present investigation was conducted to elucidate the insulin, glucose, and lactate responses to an intravenous glucose challenge after transient hepatic dearterialization in a liver tumor model in inbred Wistar-Furth rats. We found that nonfasted rats bearing dearterialized liver tumors showed slightly higher basal plasma glucose levels and an exaggerated elevation of plasma glucose during the glucose infusion compared to the controls. Further, they had a depressed insulin response to the glucose challenge. Their glycogen stores were at the same time depleted, in both the liver and the tumor tissues, and the plasma lactate production during the glucose infusion was elevated after dearterialization. We conclude that immediately after hepatic dearterialization in rats with liver malignancies, glucose intolerance and impaired glucose-induced insulin secretion exist.

Topics: Adenocarcinoma; Animals; Blood Glucose; Constriction; Glucose; Glucose Clamp Technique; Glycogen; Hepatic Artery; Insulin; Lactates; Liver; Liver Neoplasms; Male; Rats; Rats, Inbred WF

An autopsy case of glycogen-rich clear cell carcinoma (GRCCC) which arose in the right breast of a 72-year-old woman is reported. Light microscopic examination of the small finger-tip-sized tumor revealed solid alveolar proliferation of clear cells containing abundant glycogen. Immunohistochemically, most of the clear tumor cells were stained for epithelial membrane antigen (EMA) and alpha-lactalbumin, whereas a few eosinophilic tumor cells were positive for S-100 protein, EMA and actin. Electron microscopically, aggregates of glycogen particles, numerous empty glycogen lakes, microvilli, tight junctions and basal lamina were identified. Autopsy disclosed marked metastases to the liver, lung, adrenal, skin and lymph nodes. Primary breast cancer was confirmed by exclusion of a primary at any other site. It is suggested that although rare, GRCCC of the breast is as aggressive as usual invasive ductal carcinoma, and is associated with severe nodal and blood-borne metastases, followed by death.

Topics: Adenocarcinoma; Adrenal Gland Neoplasms; Aged; Breast Neoplasms; Female; Glycogen; Humans; Immunohistochemistry; Liver Neoplasms; Lung Neoplasms

The receptors for insulin and insulin-like growth factor I (IGF-I) are closely related molecules, with an extracellular binding domain and an intracellular tyrosine kinase domain. The interaction of insulin and IGF-I with their respective receptors activates the receptor kinase domain, leading to the biological actions of the hormones. Since insulin generally regulates metabolic events and IGF-I generally regulates growth events, it is believed that structural differences in the tyrosine kinase domains of the two respective receptors may elicit different biological responses via different transmembrane signaling mechanisms. We studied the regulation of glycogen metabolism and amino acid uptake in human cultured HEP-G2 hepatoma cells, which have distinct receptors for both insulin and IGF-I. The receptor specificity of these responses was probed with specific monoclonal antibodies to both the insulin and IGF-I receptors. Stimulation of both [3H]glucose incorporation into glycogen and alpha-[3H]aminoisobutyric acid uptake by insulin was half-maximal at concentrations of 1-5 nmol/L. These effects were blocked by the insulin receptor monoclonal antibody MA-10, but not by the IGF-I receptor antibody alpha IR-3. Stimulation of both functions by IGF-I was half-maximal at concentrations of 1-5 nmol/L, and these effects were inhibited by alpha IR-3, but not by MA-10. These studies indicate that in HEP-G2 cells both insulin and IGF-I, via their own receptors, stimulate the same biological responses.

Topics: Amino Acids; Aminoisobutyric Acids; Antibodies, Monoclonal; Antibody Specificity; Carcinoma, Hepatocellular; Dose-Response Relationship, Drug; Glucose; Glycogen; Humans; Insulin; Insulin-Like Growth Factor I; Liver Neoplasms; Precipitin Tests; Protein Binding; Receptor, Insulin; Receptors, Somatomedin; Somatomedins; Tumor Cells, Cultured

Insulin-like growth factor II (IGF-II) shares sequence homology and predicted three-dimensional structure with insulin and IGF-I. IGF-II can bind, therefore, to a limited extent with the receptors for these two other hormones, as well as to a distinct receptor for IGF-II. Previous studies have been unable to attribute a particular response of IGF-II through its own receptor. In the present studies, the IGF-II receptor is shown to mediate the stimulation of glycogen synthesis in human hepatoma cells since: (i) IGF-II is found to be capable of stimulating a response at concentrations in which it would primarily interact with its own receptor; (ii) the response to IGF-II was not blocked by monoclonal antibodies which inhibit the responses of cells through the insulin and IGF-I receptors; and (iii) polyclonal antibodies to the IGF-II receptor were found to mimic the ability of IGF-II to stimulate glycogen synthesis. These results indicate that the IGF-II receptor mediates a particular biological response--stimulation of glycogen synthesis in hepatoma cells. Furthermore, a monovalent Fab fragment of the polyclonal antibody to the IGF-II receptor was also shown to stimulate glycogen synthesis in these cells. These data indicate that clustering of the IGF-II receptor is not required to stimulate a biological response.

Topics: Antibodies, Monoclonal; Carcinoma, Hepatocellular; Cell Line; Glycogen; Humans; Insulin; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Kinetics; Liver Neoplasms; Receptor, Insulin; Receptors, Somatomedin; Somatomedins

Twenty-five cases of cytologically and histologically confirmed hepatocellular carcinoma (HCC) were cytomorphologically analyzed using May-Grünwald-Giemsa (MGG)-stained aspiration smears and supplemented with special stains. The cell types were categorized as well differentiated (18 cases), vacuolated (four cases), giant cell (one case), and poorly differentiated (two cases). Glycogen staining was positive in 80% of the cases and hence served as a reliable parameter of diagnostic importance in HCC. Cytoplasmic hyaline bodies (14.6%) and bile pigment (17%), when present, were other important features supporting the diagnosis of HCC. Vacuolation of the cell cytoplasm (80%) was possibly related to glycogen accumulation. The cause of nuclear vacuolation (60%) and the significance of nuclear argyrophilia as markers of abnormal cell growth remain to be studied.

Topics: Adolescent; Adult; Biopsy, Needle; Carcinoma, Hepatocellular; Cell Nucleus; Cytoplasm; Female; Glycogen; Histocytochemistry; Humans; Liver Neoplasms; Male; Middle Aged; Staining and Labeling

Topics: Animals; Carcinogens; Glycogen; Humans; Intermediate Filaments; Liver Circulation; Liver Neoplasms; Liver Neoplasms, Experimental; Precancerous Conditions; Rats; Vimentin

Chloroform enhances dose-dependently the number of preneoplastic foci in livers of weanling female Sprague-Dawley rats. The preneoplastic foci were induced with a single dose of 8 mg diethylnitrosamine (DEN)/kg body wt. Thereafter chloroform was applied twice weekly for 11 consecutive weeks in doses of 100, 200 and 400 mg/kg body wt, respectively. This treatment raised the number of adenosine-5'-triphosphatase (ATPase)-deficient foci up to 5-fold, that of gamma-glutamyltranspeptidase (GGTase) and glycogen-positive foci 13- and 10-fold, respectively, after 12 weeks; 25 mg caused no effect compared to DEN-treated controls. In contrast, daily doses of chloroform only, 200 and 400 mg/kg body wt for 33 days, and 800 mg/kg body wt for 20 days given to 3-4-week-old female Sprague-Dawley rats did not lead to island formation, measured after 12 weeks, indicating a promoting rather than an initiating potency.

Topics: Adenosine Triphosphatases; Animals; Carcinogens; Chloroform; Cocarcinogenesis; Diethylnitrosamine; Female; gamma-Glutamyltransferase; Glycogen; Liver Neoplasms; Precancerous Conditions; Rats; Rats, Inbred Strains

Insulin and the insulinlike growth factors (IGF-I and IGF-II) are members of a family of hormones that regulate the metabolism and growth of many tissues. Cultured HEP-G2 cells (a minimal deviation human hepatoma) have insulin receptors and respond to insulin by increasing their glycogen metabolism. In the present study with HEP-G2 cells, we used 125I-labeled insulin, IGF-I, and IGF-II to identify distinct receptors for each hormone by competition-inhibition studies. Unlabeled insulin was able to inhibit 125I-IGF-I binding but not 125I-IGF-II binding. A mouse monoclonal antibody to the human insulin receptor that inhibits insulin binding and blocks insulin action inhibited 75% of 125I-insulin binding, but inhibited neither 125I-IGF-I nor 125I-IGF-II binding. When glycogen metabolism was studied, insulin stimulated [3H]glucose incorporation into glycogen in a biphasic manner; one phase that was 20-30% of the maximal response occurred over 1-100 pM, and the other phase occurred over 100 pM-100 nM. The anti-receptor monoclonal antibody inhibited the first phase of insulin stimulation but not the second. Both IGF-I and IGF-II stimulated [3H]glucose incorporation over the range of 10 pM-10 nM; IGF-I was three to fivefold more potent. The monoclonal antibody, however, was without effect on IGF regulation of glycogen metabolism. Therefore, these studies indicate that insulin as well as the IGFs at physiological concentrations regulate glycogen metabolism in HEP-G2 cells. Moreover, this regulation of glycogen metabolism is mediated by both the insulin receptor and the IGF receptors.

Topics: Animals; Antibodies, Monoclonal; Binding, Competitive; Carcinoma, Hepatocellular; Cell Line; Glucose; Glycogen; Humans; Insulin; Liver Neoplasms; Mice; Peptides; Receptor, Insulin; Receptors, Cell Surface; Receptors, Somatomedin; Somatomedins

Topics: Animals; Cell Nucleus; Cytoplasm; Endoplasmic Reticulum; Glycogen; Hexachlorocyclohexane; Lipid Metabolism; Liver; Liver Neoplasms; Mice; Microscopy, Electron

Persisting focal lesions, namely glycogen storage (glycogenotic) foci and mixed cell foci, were induced in liver by treatment of rats with the hepatocarcinogen N-nitrosomorpholine in a concentration of 200 mg/l drinking water for 7 weeks. Four and seven weeks after withdrawal of the carcinogen, the persisting foci were dissected from freeze-dried cryostat sections and their glycogen content and glucose-6-phosphate dehydrogenase activity were analyzed with highly sensitive luminometrical tests. The foci composed exclusively of storage cells contained on an average 100% more glycogen than the surrounding tissue of normal appearance or the liver parenchyma of untreated control animals. The overall glycogen content of the mixed cell foci, which were composed of both glycogenotic and glycogen-poor basophilic cells, was not distinguishable from that of the normal liver tissue. The activity of the G6PDH showed a clear tendency to higher values in the majority of the small glycogen storage foci (up to 100 ng dissected material). However, in larger glycogenotic foci and in particular in the mixed cell foci the activity of this enzyme was significantly higher (by a factor of approximately 3 and 6, respectively) than in the surrounding tissue of normal appearance and in the liver parenchyma of untreated controls. The data support the concept that hepatocarcinogens induce a focal hepatic glycogen storage disease of the liver which appears to elicit adaptive enzymatic changes gradually redirecting the disturbed carbohydrate metabolism towards other metabolic pathways, such as the pentose phosphate pathway.

Topics: Animals; Carcinogens; Glucosephosphate Dehydrogenase; Glycogen; Liver; Liver Neoplasms; Male; Nitrosamines; Precancerous Conditions; Rats; Rats, Inbred Strains

A comparative morphologic, morphometric and enzyme histochemical investigation of lesions induced by short-term application of N-nitrosomorpholine (NNM) and subsequent so-called 'selection pressure' was carried out in order to assess the characteristics of the numbers of induced putative preneoplastic populations and to cast light on reversibility associated with this model. The glycogen storage foci, mixed cell foci and neoplastic nodules observed after 'selection pressure' were in principle similar to those seen after stop experiments, although alterations in morphology and enzyme phenotype of individual cells were usually far more pronounced after short-term induction. It was established that 75% of the lesions were no longer visible 11 weeks after withdrawal of induction stimuli and that a large proportion of these remaining demonstrated heterogeneity in morphological and histochemical markers indicative of reversion to normal phenotype. After a further 10 weeks a slight increase in number of foci associated with decrease in size and enhanced homogeneity in phenotypic markers was established. The behaviour of foci and nodules undergoing reversion was considered with respect to changes in basophilia and glycogen storage and activity of the enzymes glucose-6-phosphate dehydrogenase, glucose-6-phosphatase, glyceraldehyde 3-phosphate dehydrogenase, glycogen phosphorylase and synthase, acid phosphatase and gamma-glutamyl transpeptidase and correlated with location of altered cellular populations within the liver functional acinus.

Topics: Animals; Carcinogens; Enzymes; Glycogen; Liver; Liver Neoplasms; Male; Neoplasms, Experimental; Nitrosamines; Precancerous Conditions; Rats; Rats, Inbred Strains

Inbred Swiss mice were fed hexachlorocyclohexane (BHC) at 500 ppm dose level in diet for 2, 4, 6 and 8 months. Later BHC was discontinued for 4 months and subsequently the animals were refed BHC for 1 month. Glucose-6-phosphatase (G6Pase) and fructose-1,6-diphosphatase (FDPase) activity was studied at different time intervals accompanied with changes in glycogen distribution and endoplasmic reticulum (ER) proliferation in hepatocytes. G6Pase and FDPase showed a decline in activities on BHC feeding. The activities of these enzymes showed recovery on BHC discontinuation. The changes were progressive with duration of exposure. After 6 months exposure the biochemical changes became more resistant to recovery. Maximal changes occurred in 8 month-exposure and the changes were irreversible. Glycogen accumulation and depletion followed a definite pattern. After two months of BHC feeding, increase in parenchymal glycogen storage zones was observed. In the later stage of hepatocarcinogenesis and specially in tumors, glycogen was depleted considerably. Smooth endoplasmic reticulum (SER) proliferation was recorded around the 3rd and 4th month. The correlation between glycogen accumulation, SER proliferation, G6Pase and FDPase activity is discussed.

Topics: Animals; Carcinogens; Drug Administration Schedule; Endoplasmic Reticulum; Fructose-Bisphosphatase; Glucose-6-Phosphatase; Glycogen; Hexachlorocyclohexane; Liver; Liver Neoplasms; Mice; Mice, Inbred Strains; Neoplasms, Experimental; Time Factors

This paper describes a new cultured hepatoma cell line referred as ZHC cells, derived from the ascitic Zajdela rat hepatoma. Since 1963, the dedifferenciated in vivo transplanted ascitic cells were characterized by the absence of glycogen as in generally the case in all fast growing hepatic tumors. In 1974, we succeeded in adapting these tumor cell to in vitro defined growth conditions, where we observed the progressive recovery of the ability to synthesize and to store large amounts of glycogen, as shown by histochemical, ultrastructural and biochemical studies. It can now be considered as an established cell line in which the reverted phenotype has been stable for 3 years.

Topics: Animals; Carcinoma, Hepatocellular; Cell Line; Glucose; Glycogen; Liver Neoplasms; Neoplasm Proteins; Neoplasms, Experimental; Rats

In human tumors (cancer of the liver, stomach, lymphogranulomatosis of lymphnodes, metastases in lymphnodes, ascites ovarian tumor cells) the authors studied the content of enzymes participating in glycogen biosynthesis through uridine diphosphateglucose mechanism--UDPG-glycogensynthetase, UDPG-pyrophosphroylase, phosphoglucomutase. As a rule, in human tumor cells the amount of glycogen and the activity of enzymes of its biosynthesis is decreased, the more the higher proliferative activity and autonomization of tumor cells.

Topics: Enzyme Activation; Glycogen; Glycogen Synthase; Humans; Liver Neoplasms; Lymphoma; Neoplasms; Nucleotidyltransferases; Phosphoglucomutase; Stomach Neoplasms; Uridine Diphosphate Glucose; Uridine Diphosphate Sugars; UTP-Glucose-1-Phosphate Uridylyltransferase

Following formation of hyperplastic nodules, some areas of presumptive preneoplastic liver parenchyma show intense cytoplasmic RNA staining. This hyperbasophilia is not associated with increased ribosome content. Histochemical localization of metallic cations remaining after Carnoy fixation implies an inverse relationship with toluidine blue staining. In liver tissue fixed with potassium pyroantimonate, more inorganic cation precipitation occurs in nucleic of hyperbasophilic foci and hepatomas than within surrounding liver parenchyma. Electron microscopic observations of hyperbasophilic hepatocytes revealed large deposits of cation antimonate within nucleoli and nuclear interchromatin areas and finer deposits in apparent association with cytoplasmic ribosomes. Thus, differences in basophilia may reflect variations in cation levles. Since hyperbasophilic foci show increased thymidine incorporation, cell proliferation may be correlated with histochemically detected alterations of intracellular cations.

Topics: Animals; Azo Compounds; Calcium; Carcinoma, Hepatocellular; Cations, Divalent; Glycogen; Histocytochemistry; Liver Neoplasms; Male; Metals; Neoplasms, Experimental; Precancerous Conditions; Rats; RNA, Neoplasm; Staining and Labeling

The course of an infantial liver carcinoma is reported. Two liver biopsies and autopsy material were studied by light- and electron microscope. The histological findings and the clinical data are discussed. The first biopsy taken from the liver showed glycogen storage within the hepatic cells. It is suggested that this phenomenon is consistent with the preblastomatous stage of the liver cells. This fact is supported also by experimental way. The detection of this glycogen storage could be used as an early sign of the liver cancer in childhood, and might stress an early surgical intervention.

Topics: Autopsy; Biopsy; Carcinoma, Hepatocellular; Cell Transformation, Neoplastic; Female; Glycogen; Humans; Infant; Liver; Liver Neoplasms; Microscopy, Electron

Six young adult male rhesus monkeys were given diethylnitrosamine ip for 3-5 years. Liver biospies were done monthly. After 6 months, biopsy specimens showed individual hepatocytes and small foci of hepatocytes that were intensely positive for glycogen. During the second and later years, larger foci of such cells developed. In sections stained with hematoxylin and eosin, the glycogen-containing hepatocytes generally appeared unusually clear. Some hepatocytes, however, had eosinophilic or basophilic cytoplasm. Nuclear enlargement and atypic developed, particularly outside the foci. The hepatocytes within most foci were uniform in their histochemical features: glycogen was elevated, glucose-6-phosphatase was decreased, and ATPase activity was present not only along the bile canalicular surface but also along the enire cell membrane. After 3-5 years, neoplastic nodules and hepatocarcinomas developed in 5 of 6 animals. Two nodules and particularly the heptocarcinomas differed from the foci in one of more histochemical parameters. The findings suggested that the glycogen-containing, histochemically altered cells of the foci in one or more histochemical parameters. The findings suggested that the glycogen-containing, histochemically altered cells of the foci may be the first step in the development of neoplasia; further steps toward malignancy appeared to be frequently associated with additional alterations, such as loss of sinusoidal ATPase and re-formation of glucose-6-phosphatase.

Topics: Adenosine Triphosphatases; Animals; Carcinoma, Hepatocellular; Diethylnitrosamine; Glucose-6-Phosphatase; Glycogen; Haplorhini; Liver Neoplasms; Macaca mulatta; Male; Neoplasms, Experimental; Nitrosamines; Precancerous Conditions; Time Factors

Male Wistar rats were given 50 mug of aflatoxin B1 twice a week for 4 weeks, and thereafter 75 mug twice a week for 10 weeks. Their livers were investigated histologically and histochemically for glycogen, RNA, fat, alkaline and acid phosphatases, adenosine triphosphatase, 5'-nucleotidase, glucose-6-phosphatase, glucose-6-phosphate dehydrogenase, succinic dehydrogenase, and alkaline and acid nucleases. No significant lesions occurred before 15 weeks. During this period, the liver was histochemically unchanged except for a periportal decrease of alkaline phosphatase and adenosine triphosphatase. Scattered hepatocytes with a strong glucose-6-phosphatase activity appeared. These changes represent toxic effects of aflatoxin B1 and are irrelevant to carcinogenesis. From 15 weeks onward, three types of liver cell hyperplastic foci and nodules developed. Histologically, and with respect to glycogen, fat, and RNA content, only two of these types were considered as potential precursors of hepatocarcinomas. However, all types exhibited a decrease or absence of the enzymes studied. Both histological and histochemical changes stressed the complex heterogeneity existing between and within hepatic foci and nodules. From 11 months on, hepatocarcinomas developed. The tumors disclosed similar histochemical changes. This similarity further supports the "precarcinomatous" nature of hyperplastic foci and nodules. It appears that focal changes in surface as well as in cytoplasmic and nuclear enzymes are intimately and very early linked to the carcinogenic process. Whether they are fundamental or only represent an epiphenomenon remains unclear.

Topics: Acid Phosphatase; Adenosine Triphosphatases; Aflatoxins; Alkaline Phosphatase; Animals; Chemical and Drug Induced Liver Injury; Glucose-6-Phosphatase; Glucosephosphate Dehydrogenase; Glycogen; Lipid Metabolism; Liver Neoplasms; Male; Neoplasms, Experimental; Nucleotidases; Precancerous Conditions; Rats; RNA, Neoplasm; Succinate Dehydrogenase; Time Factors

Topics: Animals; Carcinoma, Hepatocellular; Glucosidases; Glycogen; Liver Neoplasms; Male; Neoplasm Transplantation; Neoplasms, Experimental; Rats

During the investigation of the histochemical synthesis of glycogen particles from glucose 1-phosphate by the phosphorylase-branching glycosyltransferase system in various tissue cells, it was observed that focal synthesis localized in a certain area of the cytoplasm occurred in some cells. This differed from the usual synthesis in which particles of similar size were synthesized within the cytoplasm. Otherwise, cytoplasmic particles of various size were also synthesized in other cells under the same histochemical condition. The possible significance of the presence of these patterns in glycogen synthesis is discussed.

Topics: Animals; Carcinoma, Hepatocellular; Cytoplasm; Glucosyltransferases; Glycogen; Histocytochemistry; Liver Neoplasms; Microscopy, Electron; Molecular Weight; Muscles; Neoplasms, Experimental; Organ Specificity; Phosphorylases; Rabbits; Rats; Subcellular Fractions

Topics: Adrenalectomy; Animals; Bucladesine; Carcinoma, Hepatocellular; Cell Line; Dactinomycin; Dexamethasone; Drug Interactions; Enzyme Induction; Glycogen; Insulin; Liver; Liver Neoplasms; Neoplasms, Experimental; Phosphoenolpyruvate Carboxykinase (GTP); Progesterone; Rats; Stimulation, Chemical; Tyrosine Transaminase

Topics: Amino Acids; Animals; Blood Glucose; Carbon Radioisotopes; Carcinoma, Brown-Pearce; Carcinoma, Ehrlich Tumor; Carcinoma, Hepatocellular; Gluconeogenesis; Glycogen; Hydrocortisone; Liver Glycogen; Liver Neoplasms; Male; Mice; Mice, Inbred C3H; Muscles; Neoplasm Transplantation; Neoplasms, Experimental; Rats; Sarcoma 180; Stimulation, Chemical; Stress, Physiological; Time Factors; Transplantation, Homologous

Topics: Animals; Endoplasmic Reticulum; Glucose-6-Phosphatase; Glycogen; Liver; Liver Neoplasms; Male; Microscopy, Electron; Morpholines; Nitroso Compounds; Rats

Topics: Adenoma, Bile Duct; Animals; Autoradiography; Carcinoma, Hepatocellular; Cell Division; Cell Nucleus; Cell Transformation, Neoplastic; Fetal Proteins; Glycogen; Hyperplasia; Immunoelectrophoresis; Liver Neoplasms; Neoplasm Metastasis; Neoplasms, Experimental; p-Dimethylaminoazobenzene; Rats; Thymidine; Tritium

Topics: Administration, Oral; Animals; Carcinoma, Hepatocellular; Cell Transformation, Neoplastic; DNA, Neoplasm; Glycogen; Histocytochemistry; Liver Neoplasms; Male; Neoplasms, Experimental; Nitrosamines; Rats; RNA, Neoplasm; Spectrophotometry; Time Factors

Topics: Animals; Carcinoma, Hepatocellular; Chemical and Drug Induced Liver Injury; Endoplasmic Reticulum; Glycogen; Hyperplasia; Liver; Liver Cirrhosis; Liver Neoplasms; Male; Microscopy, Electron; Rats; Ribosomes; Thioacetamide; Time Factors; Water

Topics: Animals; Carcinoma, Hepatocellular; Cortisone; Gluconeogenesis; Glycogen; Glycolysis; Liver; Liver Glycogen; Liver Neoplasms; Mice; Mice, Inbred C3H; Neoplasm Transplantation; Neoplasms, Experimental

Topics: Animals; Carcinoma, Hepatocellular; Fetus; Glucosyltransferases; Glycogen; Glycogen Synthase; Immunologic Techniques; Isoelectric Focusing; Isoenzymes; Liver; Liver Neoplasms; Male; Muscles; Neoplasms, Experimental; Phosphorylases; Rats; Rats, Inbred Strains

Topics: Autopsy; Carcinoma, Hepatocellular; Child; Child, Preschool; DNA, Neoplasm; Female; Glycogen; Humans; Infant; Lipids; Liver Neoplasms; Male; Neoplasm Proteins; RNA, Neoplasm; Zinc

Topics: Adenocarcinoma; Adenoma, Bile Duct; Adult; Age Factors; Aged; Carcinoma, Hepatocellular; Cytoplasm; Female; Fetal Proteins; Glycogen; Humans; Liver Cirrhosis; Liver Neoplasms; Male; Middle Aged; Neoplasm Metastasis; Neoplasm Proteins; Sex Factors; Uganda

Topics: Animals; Carcinoma, Hepatocellular; Cell Nucleolus; Cell Nucleus; Chromatin; Cytoplasm; Glycogen; Liver Neoplasms; Male; Microscopy, Electron; Nitroso Compounds; Rats; Ribosomes

Topics: Animals; Antibodies, Neoplasm; Carbon Radioisotopes; Carcinoma, Hepatocellular; Female; Fetus; Glycogen; Glycogen Synthase; Hydrogen-Ion Concentration; In Vitro Techniques; Isoelectric Focusing; Kinetics; Liver Neoplasms; Male; Muscles; Neoplasms, Experimental; Phosphorylases; Rats

Topics: Animals; Carcinoma, Hepatocellular; Feedback; Glucosyltransferases; Glycogen; Liver Neoplasms; Male; Neoplasms, Experimental; Rats

Topics: Adenocarcinoma; Adenoma, Bile Duct; Age Factors; Bile Duct Neoplasms; Carcinoma, Hepatocellular; Fetal Proteins; Glycogen; Humans; Liver Neoplasms; Uganda

Topics: Animals; Carbon Isotopes; Carcinoma, Hepatocellular; Cell Fractionation; Centrifugation, Density Gradient; Chromatography, DEAE-Cellulose; Enzyme Activation; Glucose; Glucosephosphates; Glucosyltransferases; Glycogen; Hydrogen-Ion Concentration; Isoenzymes; Kinetics; Liver; Liver Neoplasms; Maleates; Microsomes; Muscles; Neoplasms, Experimental; Nucleoside Diphosphate Sugars; Organ Specificity; Peritoneal Neoplasms; Rats; Tromethamine

Topics: Animals; Carcinoma, Hepatocellular; Centrifugation, Density Gradient; Electron Transport Complex IV; Glutamate Dehydrogenase; Glycogen; Liver Neoplasms; Mitochondria, Liver; Monoamine Oxidase; Neoplasms, Experimental; Rats; Sucrose

Topics: Alcoholism; Animals; Cholangitis; Dogs; Glucose; Glycogen; Humans; Hypoglycemia; Liver Cirrhosis; Liver Diseases; Liver Neoplasms; Rabbits; Rats

Topics: Amylases; Animals; Autoradiography; Carcinoma, Hepatocellular; Cell Nucleus; Citrates; Cytoplasm; Glucose; Glycogen; Inclusion Bodies; Lead; Liver Neoplasms; Male; Microscopy, Electron; Neoplasm Transplantation; Neoplasms, Experimental; Periodic Acid; Rats; Staining and Labeling; Time Factors; Tritium

Topics: Acid Phosphatase; Adult; Albumins; Bile Acids and Salts; Carcinoma, Hepatocellular; Esterases; Fibrinogen; Glycogen; Histocytochemistry; Humans; Hydroxyindoleacetic Acid; Lipids; Lipoproteins; Liver Neoplasms; Lung Neoplasms; Male; Malignant Carcinoid Syndrome; Microscopy, Electron; Peroxidases; Serotonin; Staining and Labeling; Transferrin

Topics: Amobarbital; Animals; Carbon Dioxide; Carbon Isotopes; Carcinoma, Hepatocellular; Dinitrophenols; Feedback; Gluconeogenesis; Glucose; Glucosyltransferases; Glycogen; Glycolysis; Hexosephosphates; Kinetics; Liver; Liver Neoplasms; Male; Neoplasm Transplantation; Neoplasms, Experimental; Nucleoside Diphosphate Sugars; Phosphoglucomutase; Rats; Rotenone; Ultracentrifugation; Uracil Nucleotides

Topics: Animals; Biopsy; Carcinoma, Hepatocellular; Cell Membrane; Cell Nucleolus; Cell Nucleus; Cytoplasm; Endoplasmic Reticulum; Glycogen; Golgi Apparatus; Humans; Inclusion Bodies; Liver; Liver Diseases; Liver Neoplasms; Microscopy, Electron; Mitochondria, Liver; Neoplasms, Experimental

Topics: Acid Phosphatase; Adenosine Triphosphatases; Alkaline Phosphatase; Animals; Carcinogens; Carcinoma, Hepatocellular; Fluorenes; Glucose-6-Phosphatase; Glucuronidase; Glycogen; Histocytochemistry; Hyperplasia; L-Lactate Dehydrogenase; Liver Diseases; Liver Neoplasms; Male; Neoplasms, Experimental; Phosphorylase Kinase; Rats; Succinate Dehydrogenase

Topics: Adenosine Diphosphate; Adenosine Triphosphate; Animals; Biotransformation; Brain; Carbon Dioxide; Carbon Isotopes; Carcinoma, Ehrlich Tumor; Carcinoma, Hepatocellular; Chromatography, Paper; Glucosamine; Glucose; Glucosephosphates; Glycogen; Isomerases; Kidney; Kinetics; Lactates; Liver; Liver Neoplasms; Lung; Male; Metabolism; Mice; Neoplasm Proteins; Neoplasms, Experimental; Oxygen Consumption; Phosphates; Rats; Sarcoma, Yoshida; Stomach

Topics: Animals; Carcinoma, Hepatocellular; Cell Nucleus; Culture Techniques; Cytoplasm; Cytoplasmic Granules; Endoplasmic Reticulum; Glycogen; Glycosaminoglycans; Haplorhini; Liver Neoplasms; Methods; Microscopy, Electron; Mitochondria, Liver; Nitrosamines

Topics: Adolescent; Carcinoma, Hepatocellular; Cortisone; Glycogen; Glycogen Storage Disease; Glycogen Storage Disease Type I; Hepatitis; Humans; Liver; Liver Cirrhosis; Liver Neoplasms; Male; Microscopy, Electron; Norethandrolone

Topics: Animals; Antineoplastic Agents; Ascites; Carcinoma, Hepatocellular; Cyclophosphamide; Female; Glucosyltransferases; Glycogen; Histocytochemistry; Liver Neoplasms; Mechlorethamine; Mitomycins; Neoplasms, Experimental; Rats

Topics: Carcinoma, Hepatocellular; Fructose-Bisphosphatase; Glucose; Glucose Tolerance Test; Glucose-6-Phosphatase; Glucosephosphate Dehydrogenase; Glucosyltransferases; Glycogen; Humans; Hypoglycemia; Insulin; L-Lactate Dehydrogenase; Lactates; Liver; Liver Glycogen; Liver Neoplasms; Muscles

Topics: Antimetabolites; Carcinoma, Hepatocellular; Cyclohexanes; Depression, Chemical; Dinitrophenols; Glucose; Glycogen; Glycolysis; In Vitro Techniques; Lactates; Liver Neoplasms; Mitochondria; Oligomycins; Oxygen Consumption; Stimulation, Chemical

Topics: Alkylating Agents; Animals; Antineoplastic Agents; Ascites; Carcinoma, Hepatocellular; Cobalt Isotopes; Colchicine; Cyclophosphamide; Dactinomycin; Female; Glycogen; Liver Neoplasms; Mechlorethamine; Mercaptopurine; Mitomycins; Neoplasm Transplantation; Neoplasms, Experimental; Oligosaccharides; Rats; Sarcoma, Yoshida

Topics: Animals; Carbohydrate Metabolism; Carcinoma, Hepatocellular; DNA; Glucokinase; Glycerophosphates; Glycogen; Glycolysis; Hepatectomy; Hexokinase; Lactates; Liver; Liver Neoplasms; Liver Regeneration; Neoplasms, Experimental; Rats; Thymidine; Tritium

Topics: Animals; Ascites; Carcinoma, Hepatocellular; Glycogen; Liver Neoplasms; Microscopy, Electron; Neoplasms, Experimental; Rats

Affinity of glucose, fructose and mannose for tumour hexokinase and their rates of phosphorylation at saturation concentration have been correlated with rates of glycogen synthesis by intact tumour cells at different concentrations of the three substrates. Competition experiments with one sugar labelled and the other sugar unlabelled indicate inhibition of glycogen synthesis by the sugar with a low K(m) for hexokinase. Glycogen synthesis from glucose 1-phosphate in aged cells and from nucleoside in freshly prepared cells is stimulated by fructose and inhibited by glucose. The decrease in glycogen formation from glucose 1-phosphate by oligomycin is partially overcome by increased fructose concentrations. These results are explained by an activation of alpha-glucan phosphorylase by fructose and an inhibition of this enzyme by glucose. It is suggested that differences in localization of glucose 6-phosphate, available to the intact cell in various ways, determine its transformation into glycogen by either the UDP-glucose-alpha-glucan glucosyltransferase reaction or by the alpha-glucan phosphorylase reaction.

Topics: Animals; Carcinoma, Hepatocellular; Cell Line; Culture Techniques; Depression, Chemical; Fructose; Glucose; Glucosyltransferases; Glycogen; Hexokinase; Hexosephosphates; Kinetics; Liver Neoplasms; Mannose; Neoplasms, Experimental; Nucleosides; Oligomycins; Rats; Stimulation, Chemical

Topics: Acid Phosphatase; Animals; Ascites; Carcinoma, Hepatocellular; Cell Line; Cytoplasm; Glycogen; Histocytochemistry; Liver; Liver Neoplasms; Lysosomes; Microscopy, Electron; Neoplasms, Experimental; Rats

Topics: Biopsy; Chemical and Drug Induced Liver Injury; Chronic Disease; Cytoplasmic Granules; Endoplasmic Reticulum; Glycogen; Hemochromatosis; Humans; Hypertrophy; Liver; Liver Cirrhosis; Liver Neoplasms; Microscopy, Electron

Topics: Animals; Carcinoma, Hepatocellular; Cytoplasm; Endoplasmic Reticulum; Glycogen; Liver Neoplasms; Membranes; Rats

Topics: Animals; Binding Sites; Carbon Isotopes; Carcinoma, Hepatocellular; Feedback; Glucose; Glucosyltransferases; Glycogen; Liver Neoplasms; Neoplasm Transplantation; Neoplasms, Experimental; Rats

Topics: Animals; Autoradiography; Carcinogens; Carcinoma, Hepatocellular; Glycogen; Hemangioendothelioma; Injections, Intravenous; Liver; Liver Cirrhosis; Liver Neoplasms; Neoplasms, Experimental; Nitrosamines; Rats

Topics: Animals; Autoradiography; Carcinogens; DNA, Neoplasm; Female; Glucose-6-Phosphatase; Glycogen; Histocytochemistry; Liver Neoplasms; Neoplasms, Experimental; Nitrosamines; Nucleosides; Phosphoric Monoester Hydrolases; Rats; RNA, Neoplasm; Tritium

Topics: Carcinoma, Hepatocellular; Cyclic AMP; Glucose-6-Phosphatase; Glucosidases; Glucosyltransferases; Glycogen; Glycoside Hydrolases; Humans; Infant; Liver Neoplasms; Phosphorylase Kinase

Topics: Animals; Carcinoma, Hepatocellular; Glycogen; Hypoglycemia; Liver; Liver Neoplasms; p-Dimethylaminoazobenzene; Rats

Topics: Acid Phosphatase; Animals; Carcinoma, Hepatocellular; Catalase; Cathepsins; Centrifugation, Density Gradient; Electron Transport Complex IV; Glucose-6-Phosphatase; Glycogen; Hydrolases; Liver; Liver Neoplasms; Microsomes, Liver; Mitochondria, Liver; Rats; Ribonucleases; Sucrose

Topics: Adult; Amino Acid Metabolism, Inborn Errors; Amino Acids; Carcinoma, Hepatocellular; Child, Preschool; Cysteine; Diet Therapy; Female; Galactosemias; Glycogen; Humans; Infant; Intellectual Disability; Liver Neoplasms; Male; Maple Syrup Urine Disease; Methionine; Middle Aged; Neuroblastoma; Phenylketonurias; Portal Vein; Pyridoxine; Serine; Sulfisoxazole; Tyrosine

A study of the enzymes of the glycogen pathway in Novikoff ascites hepatoma shows that glycogen synthetase has the lowest activity and that the tumour contains no high-K(m) soluble glucokinase. However, incubation of tumour cells with metabolizable sugars in vitro, or intraperitoneal administration of glucose into the tumour-bearing rat, results in glycogen accumulation by the tumour cells. Glycogen synthesis in the tumour is supported by aerobically produced ATP but is decreased anaerobically and by uncouplers of oxidative phosphorylation. Absence of P(i) from the incubation medium increases glycogen synthesis and decreases glycolysis. The optimum temperature for glycogen synthesis is 37 degrees . The capacity of the intact tumour cell to degrade deposited glycogen is low, but is accelerated by 2,4-dinitrophenol. Tumour homogenates prepared after osmotic shock do not incorporate [(14)C]glucose into glycogen. The glucose moiety of glucose 1-phosphate and of UDP-glucose is incorporated into glycogen by the homogenates and the incorporation of glucose 1-phosphate is greatly enhanced by AMP. Glucose 6-phosphate is a poor precursor of glycogen in the homogenate system, probably because it inhibits activation of phosphorylase b by AMP.

Topics: Adenine Nucleotides; Animals; Carbon Isotopes; Carcinoma, Hepatocellular; Glucokinase; Glucosyltransferases; Glycogen; Hexokinase; Lactates; Liver Neoplasms; Neoplasms, Experimental; Oxidative Phosphorylation; Phosphoglucomutase; Phosphoric Monoester Hydrolases; Rats; Temperature

Topics: Adenine Nucleotides; Animals; Carbon Isotopes; Carcinoma, Hepatocellular; Dinitrophenols; Glucose; Glycogen; Hexosephosphates; In Vitro Techniques; Lactates; Liver Neoplasms; Neoplasm Transplantation; Neoplasms, Experimental; Rats; Uracil Nucleotides

Topics: Carbon Isotopes; Carcinoma, Hepatocellular; Dinitrophenols; Glycogen; Hexoses; In Vitro Techniques; Liver Neoplasms; Neoplasms, Experimental

Topics: Animals; Carcinogens; Ethionine; Fluorenes; Glucose-6-Phosphatase; Glucosyltransferases; Glycogen; Hyperplasia; Liver; Liver Glycogen; Liver Neoplasms; Male; Neoplasms, Experimental; Nucleic Acids; Proteins; Rats

Topics: Animals; Carcinoma, Hepatocellular; Cytoplasm; Glycogen; Liver; Liver Neoplasms; Male; Neoplasms, Experimental; Rats; Succinate Dehydrogenase

Topics: Animals; Carcinoma, Hepatocellular; Cell Nucleus; Cytoplasm; Endoplasmic Reticulum; Glycogen; Liver Neoplasms; Microscopy, Electron; Mitochondria; Neoplasms, Experimental; Rats

Topics: Adenine Nucleotides; Animals; Carcinoma, Hepatocellular; Depression, Chemical; Fructose; Fructose-Bisphosphatase; Glucose; Glucose-6-Phosphatase; Glucosyltransferases; Glycogen; Liver; Liver Neoplasms; Neoplasms, Experimental; Phosphates; Phosphoglucomutase; Phosphoric Monoester Hydrolases; Phosphotransferases; Rats; Sarcoma, Yoshida

Topics: Animals; Autoradiography; Carcinoma, Hepatocellular; DNA, Neoplasm; Female; Glycogen; Histocytochemistry; Liver Neoplasms; Neoplasms, Experimental; Rats; Thymidine; Tritium

Topics: Animals; Autoradiography; Carcinoma, Hepatocellular; DNA, Neoplasm; Female; Glucosyltransferases; Glycogen; Histocytochemistry; Liver Neoplasms; Neoplasms, Experimental; Rats; Thymidine; Tritium

Topics: Animals; Autoradiography; Carcinoma, Hepatocellular; DNA, Neoplasm; Glycogen; Histocytochemistry; Liver Neoplasms; Neoplasms, Experimental; Rats; RNA, Neoplasm; Tritium

Topics: Animals; Arginase; Carcinoma, Hepatocellular; Diet; Female; Glucokinase; Glucosephosphate Dehydrogenase; Glycogen; Hexokinase; Liver; Liver Neoplasms; Male; Neoplasm Transplantation; Neoplasms, Experimental; p-Dimethylaminoazobenzene; Proteins; Rats

Topics: Alcohol Oxidoreductases; Animals; Caseins; Glucosephosphate Dehydrogenase; Glucosyltransferases; Glycogen; Histocytochemistry; In Vitro Techniques; Lipids; Liver; Liver Neoplasms; Male; p-Dimethylaminoazobenzene; Rats; Succinate Dehydrogenase

Topics: Animals; Carcinoma; Glucosephosphate Dehydrogenase; Glycogen; In Vitro Techniques; Liver; Liver Neoplasms; Neoplasms, Experimental; Oxidoreductases; Rats

Topics: Acrylic Resins; Biopsy; Carcinoma, Hepatocellular; Coloring Agents; Glycogen; Jejunum; Kidney; Liver; Liver Neoplasms; Methenamine; Microtomy; Mucins; Periodic Acid; Rats; Silver; Staining and Labeling

Topics: Ascites; Carcinoma, Hepatocellular; Glycogen; Glycolysis; Liver; Liver Glycogen; Liver Neoplasms; Neoplasms; Neoplasms, Experimental; Research

Topics: Adenine Nucleotides; Ascites; Carbohydrate Metabolism; Carcinoma, Hepatocellular; Dinitrophenols; Glucose; Glycogen; Glycolysis; Lactates; Liver Neoplasms; Oxygen; Pharmacology; Research; Tissue Culture Techniques

Topics: Animals; Carcinoma, Hepatocellular; Chemical Phenomena; Chemistry; Glycogen; In Vitro Techniques; Liver Neoplasms; Mice; Rats

Topics: Azo Compounds; Coloring Agents; Glucokinase; Glycogen; Hexokinase; Humans; Liver Glycogen; Liver Neoplasms; Phosphorylation

Topics: Biopsy; Glycogen; Hepatitis; Histocytochemistry; Humans; Liver; Liver Cirrhosis; Liver Diseases; Liver Glycogen; Liver Neoplasms; Phosphorylases; Phosphotransferases

Topics: Carcinoma, Hepatocellular; Child; Glycogen; Glycogen Storage Disease; Glycogen Storage Disease Type I; Humans; Infant; Liver Neoplasms

Topics: Animals; Carcinoma, Hepatocellular; Coloring Agents; Glycogen; Histological Techniques; Liver Neoplasms; Liver Neoplasms, Experimental; Rats; Staining and Labeling