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Singh AK, Chaube B, Citrin KM, Fowler JW, Lee S, Catarino J, Knight J, Lowery S, Shree S, Boutagy N, Ruz-Maldonado I, Harry K, Shanabrough M, Ross TT, Malaker S, Suárez Y, Fernández-Hernando C, Grabinska K, Sessa WC. Loss of cis-PTase function in the liver promotes a highly penetrant form of fatty liver disease that rapidly transitions to hepatocellular carcinoma. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.13.566870. [PMID: 38014178 PMCID: PMC10680637 DOI: 10.1101/2023.11.13.566870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Obesity-linked fatty liver is a significant risk factor for hepatocellular carcinoma (HCC)1,2; however, the molecular mechanisms underlying the transition from non-alcoholic fatty liver disease (NAFLD) to HCC remains unclear. The present study explores the role of the endoplasmic reticulum (ER)-associated protein NgBR, an essential component of the cis-prenyltransferases (cis-PTase) enzyme3, in chronic liver disease. Here we show that genetic depletion of NgBR in hepatocytes of mice (N-LKO) intensifies triacylglycerol (TAG) accumulation, inflammatory responses, ER/oxidative stress, and liver fibrosis, ultimately resulting in HCC development with 100% penetrance after four months on a high-fat diet. Comprehensive genomic and single cell transcriptomic atlas from affected livers provides a detailed molecular analysis of the transition from liver pathophysiology to HCC development. Importantly, pharmacological inhibition of diacylglycerol acyltransferase-2 (DGAT2), a key enzyme in hepatic TAG synthesis, abrogates diet-induced liver damage and HCC burden in N-LKO mice. Overall, our findings establish NgBR/cis-PTase as a critical suppressor of NAFLD-HCC conversion and suggests that DGAT2 inhibition may serve as a promising therapeutic approach to delay HCC formation in patients with advanced non-alcoholic steatohepatitis (NASH).
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Affiliation(s)
- Abhishek K. Singh
- Department of Pharmacology, and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, Connecticut, 06520, USA
| | - Balkrishna Chaube
- Department of Comparative Medicine, Yale Center for Molecular and Systems Metabolism and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
| | - Kathryn M Citrin
- Department of Comparative Medicine, Yale Center for Molecular and Systems Metabolism and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
| | - Joseph Wayne Fowler
- Department of Pharmacology, and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, Connecticut, 06520, USA
| | - Sungwoon Lee
- Department of Pharmacology, and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, Connecticut, 06520, USA
| | - Jonatas Catarino
- Integrative Cell Signaling and Neurobiology of Metabolism Program, Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - James Knight
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | - Sarah Lowery
- Chemistry Research Building, Yale University, New Haven, CT, USA
| | - Sonal Shree
- Molecular Biophysics & Biochemistry, Yale University, New Haven, CT, USA
| | - Nabil Boutagy
- Department of Pharmacology, and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, Connecticut, 06520, USA
| | - Inmaculada Ruz-Maldonado
- Department of Comparative Medicine, Yale Center for Molecular and Systems Metabolism and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
| | - Kathy Harry
- Department of Internal Medicine, Yale University, New Haven, CT, USA
| | - Marya Shanabrough
- Integrative Cell Signaling and Neurobiology of Metabolism Program, Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
| | | | - Stacy Malaker
- Chemistry Research Building, Yale University, New Haven, CT, USA
| | - Yajaira Suárez
- Department of Comparative Medicine, Yale Center for Molecular and Systems Metabolism and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - Carlos Fernández-Hernando
- Department of Comparative Medicine, Yale Center for Molecular and Systems Metabolism and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - Kariona Grabinska
- Department of Pharmacology, and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, Connecticut, 06520, USA
| | - William C. Sessa
- Department of Pharmacology, and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, Connecticut, 06520, USA
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Liu HY, Pedros C, Kong KF, Canonigo-Balancio AJ, Xue W, Altman A. Leveraging the Treg-intrinsic CTLA4-PKCη signaling pathway for cancer immunotherapy. J Immunother Cancer 2021; 9:jitc-2021-002792. [PMID: 34588224 PMCID: PMC8483050 DOI: 10.1136/jitc-2021-002792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2021] [Indexed: 12/03/2022] Open
Abstract
Background Our previous studies revealed a critical role of a novel CTLA4-protein kinase C-eta (PKCη) signaling axis in mediating the suppressive activity of regulatory T cells (Tregs) in antitumor immunity. These studies have employed adoptive transfer of germline PKCη-deficient (Prkch−/−) Tregs into Prkch+/+ mice prior to tumor implantation. Here, we extended these findings into a biologically and clinically more relevant context. Methods We have analyzed the role of PKCη in antitumor immunity and the tumor microenvironment (TME) in intact tumor-bearing mice with Treg-specific or CD8+ T cell-specific Prkch deletion, including in a therapeutic model of combinatorial treatment. In addition to measuring tumor growth, we analyzed the phenotype and functional attributes of tumor-infiltrating immune cells, particularly Tregs and dendritic cells (DCs). Results Using two models of mouse transplantable cancer and a genetically engineered autochthonous hepatocellular carcinoma (HCC) model, we found, first, that mice with Treg-specific Prkch deletion displayed a significantly reduced growth of B16–F10 melanoma and TRAMP-C1 adenocarcinoma tumors. Tumor growth reduction was associated with a less immunosuppressive TME, indicated by increased numbers and function of tumor-infiltrating CD8+ effector T cells and elevated expression of the costimulatory ligand CD86 on intratumoral DCs. In contrast, CD8+ T cell-specific Prkch deletion had no effect on tumor growth or the abundance and functionality of CD8+ effector T cells, consistent with findings that Prkch−/− CD8+ T cells proliferated normally in response to in vitro polyclonal or specific antigen stimulation. Similar beneficial antitumor effects were found in mice with germline or Treg-specific Prkch deletion that were induced to develop an autochthonous HCC. Lastly, using a therapeutic model, we found that monotherapies consisting of Treg-specific Prkch deletion or vaccination with irradiated Fms-like tyrosine kinase 3 ligand (Flt3L)-expressing B16–F10 tumor cells post-tumor implantation significantly delayed tumor growth. This effect was more pronounced in mice receiving a combination of the two immunotherapies. Conclusion These findings demonstrate the potential utility of PKCη inhibition as a viable clinical approach to treat patients with cancer, especially when combined with adjuvant therapies.
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Affiliation(s)
- Hsin-Yu Liu
- La Jolla Institute for Immunology, La Jolla, California, USA
| | - Christophe Pedros
- La Jolla Institute for Immunology, La Jolla, California, USA.,CERTIS, San Diego, California, USA
| | - Kok-Fai Kong
- La Jolla Institute for Immunology, La Jolla, California, USA
| | | | - Wen Xue
- University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Amnon Altman
- La Jolla Institute for Immunology, La Jolla, California, USA
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Zhang X, Coker OO, Chu ESH, Fu K, Lau HCH, Wang YX, Chan AWH, Wei H, Yang X, Sung JJY, Yu J. Dietary cholesterol drives fatty liver-associated liver cancer by modulating gut microbiota and metabolites. Gut 2021; 70:761-774. [PMID: 32694178 PMCID: PMC7948195 DOI: 10.1136/gutjnl-2019-319664] [Citation(s) in RCA: 390] [Impact Index Per Article: 130.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 06/04/2020] [Accepted: 06/15/2020] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Non-alcoholic fatty liver disease (NAFLD)-associated hepatocellular carcinoma (HCC) is an increasing healthcare burden worldwide. We examined the role of dietary cholesterol in driving NAFLD-HCC through modulating gut microbiota and its metabolites. DESIGN High-fat/high-cholesterol (HFHC), high-fat/low-cholesterol or normal chow diet was fed to C57BL/6 male littermates for 14 months. Cholesterol-lowering drug atorvastatin was administered to HFHC-fed mice. Germ-free mice were transplanted with stools from mice fed different diets to determine the direct role of cholesterol modulated-microbiota in NAFLD-HCC. Gut microbiota was analysed by 16S rRNA sequencing and serum metabolites by liquid chromatography-mass spectrometry (LC-MS) metabolomic analysis. Faecal microbial compositions were examined in 59 hypercholesterolemia patients and 39 healthy controls. RESULTS High dietary cholesterol led to the sequential progression of steatosis, steatohepatitis, fibrosis and eventually HCC in mice, concomitant with insulin resistance. Cholesterol-induced NAFLD-HCC formation was associated with gut microbiota dysbiosis. The microbiota composition clustered distinctly along stages of steatosis, steatohepatitis and HCC. Mucispirillum, Desulfovibrio, Anaerotruncus and Desulfovibrionaceae increased sequentially; while Bifidobacterium and Bacteroides were depleted in HFHC-fed mice, which was corroborated in human hypercholesteremia patients. Dietary cholesterol induced gut bacterial metabolites alteration including increased taurocholic acid and decreased 3-indolepropionic acid. Germ-free mice gavaged with stools from mice fed HFHC manifested hepatic lipid accumulation, inflammation and cell proliferation. Moreover, atorvastatin restored cholesterol-induced gut microbiota dysbiosis and completely prevented NAFLD-HCC development. CONCLUSIONS Dietary cholesterol drives NAFLD-HCC formation by inducing alteration of gut microbiota and metabolites in mice. Cholesterol inhibitory therapy and gut microbiota manipulation may be effective strategies for NAFLD-HCC prevention.
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Affiliation(s)
- Xiang Zhang
- State Key Laboratory of Digestive Disease, Institute of Digestive Disease and The Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Olabisi Oluwabukola Coker
- State Key Laboratory of Digestive Disease, Institute of Digestive Disease and The Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Eagle SH Chu
- State Key Laboratory of Digestive Disease, Institute of Digestive Disease and The Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Kaili Fu
- State Key Laboratory of Digestive Disease, Institute of Digestive Disease and The Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Harry C H Lau
- State Key Laboratory of Digestive Disease, Institute of Digestive Disease and The Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Yi-Xiang Wang
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Anthony W H Chan
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Hong Wei
- Department of Precision Medicine, Sun Yat-Sen University First Affiliated Hospital, Guangzhou, Guangdong, China,Department of Laboratory Animal Science, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Xiaoyong Yang
- Department of Comparative Medicine and Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Joseph J Y Sung
- State Key Laboratory of Digestive Disease, Institute of Digestive Disease and The Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Jun Yu
- State Key Laboratory of Digestive Disease, Institute of Digestive Disease and The Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong SAR, China
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Li YZ, Di Cristofano A, Woo M. Metabolic Role of PTEN in Insulin Signaling and Resistance. Cold Spring Harb Perspect Med 2020; 10:a036137. [PMID: 31964643 PMCID: PMC7397839 DOI: 10.1101/cshperspect.a036137] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Phosphatase and tensin homolog (PTEN) is most prominently known for its function in tumorigenesis. However, a metabolic role of PTEN is emerging as a result of its altered expression in type 2 diabetes (T2D), which results in impaired insulin signaling and promotion of insulin resistance during the pathogenesis of T2D. PTEN functions in regulating insulin signaling across different organs have been identified. Through the use of a variety of models, such as tissue-specific knockout (KO) mice and in vitro cell cultures, PTEN's role in regulating insulin action has been elucidated across many cell types. Herein, we will review the recent advancements in the understanding of PTEN's metabolic functions in each of the tissues and cell types that contribute to regulating systemic insulin sensitivity and discuss how PTEN may represent a promising therapeutic strategy for treatment or prevention of T2D.
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Affiliation(s)
- Yu Zhe Li
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 2C4, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario M5G 2M9, Canada
| | - Antonio Di Cristofano
- Department of Developmental and Molecular Biology and Medicine (Oncology), Albert Einstein College of Medicine and Albert Einstein Cancer Center, Bronx, New York 10461, USA
| | - Minna Woo
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 2C4, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario M5G 2M9, Canada
- Department of Immunology, University of Toronto, Toronto, Ontario M5G 2M9, Canada
- Division of Endocrinology and Metabolism, Department of Medicine, University Health Network/Mount Sinai Hospital, University of Toronto, Toronto, Ontario M5G 2C4, Canada
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Lee YR, Pandolfi PP. PTEN Mouse Models of Cancer Initiation and Progression. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a037283. [PMID: 31570383 DOI: 10.1101/cshperspect.a037283] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is one of the most frequently mutated, deleted, and functionally inactivated tumor suppressor genes in human cancer. PTEN is found mutated both somatically and in the germline of patients with PTEN hamartoma tumor syndrome (PHTS). PTEN encodes a dual lipid and protein phosphatase that dephosphorylates the lipid phosphatidylinositol-3,4,5-trisphosphate (PIP3), in turn negatively regulating the oncogenic PI3K-AKT pathway, a key proto-oncogenic player in cancer development and progression. Because of importance of PTEN in tumorigenesis, a large number of sophisticated genetically engineered mouse models (GEMMs) has been designed to elucidate the underlying mechanisms by which the "PTEN pathway" promotes tumorigenesis, while simultaneously providing a well-tailored system for the identification of novel therapies and offering platforms for new drug discoveries. This review summarizes the major cancer mouse models through which the PTEN pathway has been genetically deconstructed, and outlines the rapid development of GEMMs toward more detailed functional and tissue-specific analysis.
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Affiliation(s)
- Yu-Ru Lee
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA
| | - Pier Paolo Pandolfi
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA
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Tu T, Chen J, Chen L, Stiles BL. Dual-Specific Protein and Lipid Phosphatase PTEN and Its Biological Functions. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a036301. [PMID: 31548229 DOI: 10.1101/cshperspect.a036301] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) encodes a 403-amino acid protein with an amino-terminal domain that shares sequence homology with the actin-binding protein tensin and the putative tyrosine-protein phosphatase auxilin. Crystal structure analysis of PTEN has revealed a C2 domain that binds to phospholipids in membranes and a phosphatase domain that displays dual-specific activity toward both tyrosine (Y), serine (S)/threonine (T), as well as lipid substrates in vitro. Characterized primarily as a lipid phosphatase, PTEN plays important roles in multiple cellular processes including cell growth/survival as well as metabolism.
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Affiliation(s)
- Taojian Tu
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033, USA
| | - Jingyu Chen
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033, USA
| | - Lulu Chen
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033, USA
| | - Bangyan L Stiles
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033, USA.,Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
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Dayton TL, Gocheva V, Miller KM, Israelsen WJ, Bhutkar A, Clish CB, Davidson SM, Luengo A, Bronson RT, Jacks T, Vander Heiden MG. Germline loss of PKM2 promotes metabolic distress and hepatocellular carcinoma. Genes Dev 2016; 30:1020-33. [PMID: 27125672 PMCID: PMC4863734 DOI: 10.1101/gad.278549.116] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 03/23/2016] [Indexed: 12/12/2022]
Abstract
Alternative splicing of the Pkm gene product generates the PKM1 and PKM2 isoforms of pyruvate kinase (PK), and PKM2 expression is closely linked to embryogenesis, tissue regeneration, and cancer. To interrogate the functional requirement for PKM2 during development and tissue homeostasis, we generated germline PKM2-null mice (Pkm2(-/-)). Unexpectedly, despite being the primary isoform expressed in most wild-type adult tissues, we found that Pkm2(-/-) mice are viable and fertile. Thus, PKM2 is not required for embryonic or postnatal development. Loss of PKM2 leads to compensatory expression of PKM1 in the tissues that normally express PKM2. Strikingly, PKM2 loss leads to spontaneous development of hepatocellular carcinoma (HCC) with high penetrance that is accompanied by progressive changes in systemic metabolism characterized by altered systemic glucose homeostasis, inflammation, and hepatic steatosis. Therefore, in addition to its role in cancer metabolism, PKM2 plays a role in controlling systemic metabolic homeostasis and inflammation, thereby preventing HCC by a non-cell-autonomous mechanism.
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Affiliation(s)
- Talya L Dayton
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Vasilena Gocheva
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Kathryn M Miller
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - William J Israelsen
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Arjun Bhutkar
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Clary B Clish
- Metabolite Profiling Platform, Broad Institute, Cambridge, Massachusetts 02142, USA
| | - Shawn M Davidson
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Alba Luengo
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Roderick T Bronson
- Department of Pathology, Tufts University School of Medicine and Veterinary Medicine, North Grafton, Massachusetts 01536, USA
| | - Tyler Jacks
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Matthew G Vander Heiden
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA
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Teng YC, Shen ZQ, Kao CH, Tsai TF. Hepatocellular carcinoma mouse models: Hepatitis B virus-associated hepatocarcinogenesis and haploinsufficient tumor suppressor genes. World J Gastroenterol 2016; 22:300-325. [PMID: 26755878 PMCID: PMC4698494 DOI: 10.3748/wjg.v22.i1.300] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 10/14/2015] [Accepted: 11/24/2015] [Indexed: 02/06/2023] Open
Abstract
The multifactorial and multistage pathogenesis of hepatocellular carcinoma (HCC) has fascinated a wide spectrum of scientists for decades. While a number of major risk factors have been identified, their mechanistic roles in hepatocarcinogenesis still need to be elucidated. Many tumor suppressor genes (TSGs) have been identified as being involved in HCC. These TSGs can be classified into two groups depending on the situation with respect to allelic mutation/loss in the tumors: the recessive TSGs with two required mutated alleles and the haploinsufficient TSGs with one required mutated allele. Hepatitis B virus (HBV) is one of the most important risk factors associated with HCC. Although mice cannot be infected with HBV due to the narrow host range of HBV and the lack of a proper receptor, one advantage of mouse models for HBV/HCC research is the numerous and powerful genetic tools that help investigate the phenotypic effects of viral proteins and allow the dissection of the dose-dependent action of TSGs. Here, we mainly focus on the application of mouse models in relation to HBV-associated HCC and on TSGs that act either in a recessive or in a haploinsufficient manner. Discoveries obtained using mouse models will have a great impact on HCC translational medicine.
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Mann JP, Semple RK, Armstrong MJ. How Useful Are Monogenic Rodent Models for the Study of Human Non-Alcoholic Fatty Liver Disease? Front Endocrinol (Lausanne) 2016; 7:145. [PMID: 27899914 PMCID: PMC5110950 DOI: 10.3389/fendo.2016.00145] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 11/01/2016] [Indexed: 12/22/2022] Open
Abstract
Improving understanding of the genetic basis of human non-alcoholic fatty liver disease (NAFLD) has the potential to facilitate risk stratification of affected patients, permit personalized treatment, and inform development of new therapeutic strategies. Animal models have been widely used to interrogate the pathophysiology of, and genetic predisposition to, NAFLD. Nevertheless, considerable interspecies differences in intermediary metabolism potentially limit the extent to which results can be extrapolated to humans. For example, human genome-wide association studies have identified polymorphisms in PNPLA3 and TM6SF2 as the two most prevalent determinants of susceptibility to NAFLD and its inflammatory component (NASH), but animal models of these mutations have had only variable success in recapitulating this link. In this review, we critically appraise selected murine monogenic models of NAFLD, NASH, and hepatocellular carcinoma (HCC) with a focus on how closely they mirror human disease.
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Affiliation(s)
- Jake P. Mann
- Department of Paediatrics, University of Cambridge, Cambridge, UK
| | - Robert K. Semple
- The University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
- The National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, UK
- *Correspondence: Robert K. Semple,
| | - Matthew J. Armstrong
- Centre for Liver Research, National Institute for Health Research (NIHR) Birmingham Liver Biomedical Research Unit, University of Birmingham, Birmingham, UK
- Liver Unit, Queen Elizabeth University Hospital Birmingham, Birmingham, UK
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CRISPR/Cas9 somatic multiplex-mutagenesis for high-throughput functional cancer genomics in mice. Proc Natl Acad Sci U S A 2015; 112:13982-7. [PMID: 26508638 DOI: 10.1073/pnas.1512392112] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Here, we show CRISPR/Cas9-based targeted somatic multiplex-mutagenesis and its application for high-throughput analysis of gene function in mice. Using hepatic single guide RNA (sgRNA) delivery, we targeted large gene sets to induce hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). We observed Darwinian selection of target genes, which suppress tumorigenesis in the respective cellular/tissue context, such as Pten or Cdkn2a, and conversely found low frequency of Brca1/2 alterations, explaining mutational spectra in human ICC/HCC. Our studies show that multiplexed CRISPR/Cas9 can be used for recessive genetic screening or high-throughput cancer gene validation in mice. The analysis of CRISPR/Cas9-induced tumors provided support for a major role of chromatin modifiers in hepatobiliary tumorigenesis, including that of ARID family proteins, which have recently been reported to be mutated in ICC/HCC. We have also comprehensively characterized the frequency and size of chromosomal alterations induced by combinatorial sgRNA delivery and describe related limitations of CRISPR/Cas9 multiplexing, as well as opportunities for chromosome engineering in the context of hepatobiliary tumorigenesis. Our study describes novel approaches to model and study cancer in a high-throughput multiplexed format that will facilitate the functional annotation of cancer genomes.
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Abstract
In 2007, three scientists, Drs. Mario R. Capecchi, Martin J. Evans, and Oliver Smithies, received the Nobel Prize in Physiology or Medicine for their contributions of introducing specific gene modifications into mice. This technology, commonly referred to as gene targeting or knockout, has proven to be a powerful means for precisely manipulating the mammalian genome and has generated great impacts on virtually all phases of mammalian biology and basic biomedical research. Of note, germline mutations of many genes, especially tumor suppressors, often result in lethality during embryonic development or at developmental stages before tumor formation. This obstacle has been effectively overcome by the use of conditional knockout technology in conjunction with Cre-LoxP- or Flp-Frt-mediated temporal and/or spatial systems to generate genetic switches for precise DNA recombination. Currently, numerous conditional knockout mouse models have been successfully generated and applied in studying tumor initiation, progression, and metastasis. This review summarizes some conditional mutant mouse models that are widely used in cancer research and our understanding of the possible mechanisms underlying tumorigenesis.
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Affiliation(s)
- Chu-Xia Deng
- Genetics of Development and Disease Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
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Herbal medicines for the treatment of nonalcoholic steatohepatitis: current scenario and future prospects. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 2014:648308. [PMID: 24987431 PMCID: PMC4060323 DOI: 10.1155/2014/648308] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 04/30/2014] [Indexed: 12/11/2022]
Abstract
Nonalcoholic steatohepatitis (NASH) is a multifactorial disease and has close correlations with other metabolic disorders. This makes its treatment difficult using a single pharmacological drug. Use of plant extract/decoction or polyherbal formulation to treat various liver diseases is very well mentioned in various traditional systems of medicine (Ayurveda, Japanese or traditional Chinese Medicine, and Kampo medicine). Medicinal herbs are known for their multifaceted implications and thus can form an effective treatment schedule against NASH. Till date, several plant extracts, polyherbal formulations, and phytochemicals have been evaluated for their possible therapeutic potential in preventing onset and progression of NASH in experimental models, but clinical studies using the same are sparse. Herbal extracts with antioxidants, antidiabetic, and antihyperlipidemic properties have been shown to ameliorate symptoms of NASH. This review article is a meticulous compilation of our current knowledge on the role of natural products in alleviating NASH and possible lacunae in research that needs to be addressed.
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Yue S, Rao J, Zhu J, Busuttil RW, Kupiec-Weglinski JW, Lu L, Wang X, Zhai Y. Myeloid PTEN deficiency protects livers from ischemia reperfusion injury by facilitating M2 macrophage differentiation. THE JOURNAL OF IMMUNOLOGY 2014; 192:5343-5353. [PMID: 24771857 DOI: 10.4049/jimmunol.1400280] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Although the role of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in regulating cell proliferation is well established, its function in immune responses remains to be fully appreciated. In the current study, we analyzed myeloid-specific PTEN function in regulating tissue inflammatory immune response in a murine liver partial warm ischemia model. Myeloid-specific PTEN knockout (KO) resulted in liver protection from ischemia reperfusion injury (IRI) by deviating the local innate immune response against ischemia reperfusion toward the regulatory type: expression of proinflammatory genes was selectively decreased and anti-inflammatory IL-10 was simultaneously increased in ischemia reperfusion livers of PTEN KO mice compared with those of wild-type (WT) mice. PI3K inhibitor and IL-10-neutralizing Abs, but not exogenous LPS, recreated liver IRI in these KO mice. At the cellular level, Kupffer cells and peritoneal macrophages isolated from KO mice expressed higher levels of M2 markers and produced lower TNF-α and higher IL-10 in response to TLR ligands than did their WT counterparts. They had enhanced Stat3- and Stat6-signaling pathway activation, but diminished Stat1-signaling pathway activation, in response to TLR4 stimulation. Inactivation of Kupffer cells by gadolinium chloride enhanced proinflammatory immune activation and increased IRI in livers of myeloid PTEN KO mice. Thus, myeloid PTEN deficiency protects livers from IRI by facilitating M2 macrophage differentiation.
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Affiliation(s)
- Shi Yue
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA
| | - Jianhua Rao
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA.,Department of Liver Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiansu Province, China
| | - Jianjun Zhu
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA.,Department of Liver Surgery, Renji Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Ronald W Busuttil
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA
| | - Jerzy W Kupiec-Weglinski
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA
| | - Ling Lu
- Department of Liver Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiansu Province, China
| | - Xuehao Wang
- Department of Liver Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiansu Province, China
| | - Yuan Zhai
- Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA
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Rosiglitazone regulates anti-inflammation and growth inhibition via PTEN. BIOMED RESEARCH INTERNATIONAL 2014; 2014:787924. [PMID: 24757676 PMCID: PMC3971553 DOI: 10.1155/2014/787924] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 01/18/2014] [Accepted: 02/01/2014] [Indexed: 12/13/2022]
Abstract
Peroxisome proliferator-activated receptor gamma (PPARγ) agonist has anti-inflammatory and anticancer properties. However, the mechanisms by which PPARγ agonist rosiglitazone interferes with inflammation and cancer via phosphatase and tensin homolog-(PTEN)-dependent pathway remain unclear. We found that lower doses (<25 μ M) of rosiglitazone significantly inhibited lipopolysaccharide-(LPS)-induced nitric oxide (NO) release (via inducible nitric oxide synthase, iNOS), prostaglandin E2 (PGE2) production (via cyclooxygenase-2, COX-2), and activation of Akt in RAW 264.7 murine macrophages. However, rosiglitazone did not inhibit the production of reactive oxygen species (ROS). In PTEN knockdown (shPTEN) cells exposed to LPS, rosiglitazone did not inhibit NO release, PGE2 production, and activation of Akt. These cells had elevated basal levels of iNOS, COX-2, and ROS. However, higher doses (25-100 μ M) of rosiglitazone, without LPS stimulation, did not block NO release and PGE2 productions, but they inhibited p38 MAPK phosphorylation and blocked ROS generation in shPTEN cells. In addition, rosiglitazone caused G1 arrest and reduced the number of cells in S + G2/M phase, leading to growth inhibition. These results indicate that the anti-inflammatory property of rosiglitazone is related to regulation of PTEN independent of inhibition on ROS production. However, rosiglitazone affected the dependence of PTEN-deficient cell growth on ROS.
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Gastrointestinal and hepatotoxicity assessment of an anticancer extract from muricid molluscs. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2013; 2013:837370. [PMID: 23690858 PMCID: PMC3652158 DOI: 10.1155/2013/837370] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 03/21/2013] [Indexed: 12/15/2022]
Abstract
Marine molluscs from the family Muricidae are under development as a potential medicinal food for the prevention of colon cancer and treatment of gynaecological cancers. Here we report the outcome of the first in vivo toxicity assessment on an anticancer extract from a muricid mollusc containing brominated indole derivatives. Mice received the concentrated lipophilic extract by daily oral gavage over a two-week period. Mortality or clinical toxicity symptoms resulting from the extract were not detected during the trial, and there was no difference in the body weight of treated and control mice at the end of the trial. Histological analysis revealed some evidence for mild, idiosyncratic effects on the gastrointestinal tract and liver, including necrosis, fatty change, and inflammation in a small proportion (<40%) of mice. This is likely to result from first-pass hepatic metabolism of tyrindoxyl sulphate combined with second-pass metabolism of indoles. Overall however, oral administration of muricid extract containing brominated indoles does not result in severe clinical toxicity.
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Shearn CT, Smathers RL, Stewart BJ, Fritz KS, Galligan JJ, Hail N, Petersen DR. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) inhibition by 4-hydroxynonenal leads to increased Akt activation in hepatocytes. Mol Pharmacol 2011; 79:941-52. [PMID: 21415306 DOI: 10.1124/mol.110.069534] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The production of reactive aldehydes such as 4-hydroxynonenal (4-HNE) is proposed to be an important factor in the etiology of alcoholic liver disease. To understand the effects of 4-HNE on homeostatic signaling pathways in hepatocytes, cellular models consisting of the human hepatocellular carcinoma cell line (HepG2) and primary rat hepatocytes were evaluated. Treatment of both HepG2 cells and primary hepatocytes with subcytotoxic concentrations of 4-HNE resulted in the activation of Akt within 30 min as demonstrated by increased phosphorylation of residues Ser473 and Thr308. Quantification and subsequent immunocytochemistry of phosphatidylinositol-3,4,5-trisphosphate [PtdIns(3,4,5)P(3)[rsqb] resulted in a 6-fold increase in total PtdIns(3,4,5)P(3) and increased immunostaining at the plasma membrane after 4-HNE treatment. Cotreatment of HepG2 cells with 4-HNE and the phosphatidylinositol 3-kinase (PI3K) inhibitor 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (Ly294002) or the protein phosphatase 2A (PP2A) inhibitor okadaic acid revealed that the mechanism of activation of Akt is PI3K-dependent and PP2A-independent. Using biotin hydrazide detection, it was established that the incubation of HepG2 cells with 4-HNE resulted in increased carbonylation of the lipid phosphatase known as "phosphatase and tensin homolog deleted on chromosome 10" (PTEN), a key regulator of Akt activation. Activity assays both in HepG2 cells and recombinant PTEN revealed a decrease in PTEN lipid phosphatase activity after 4-HNE application. Mass spectral analysis of 4-HNE-treated recombinant PTEN detected a single 4-HNE adduct. Subsequent analysis of Akt dependent physiological consequences of 4-HNE in HepG2 cells revealed significant increases in the accumulation of neutral lipids. These results provide a potential mechanism of Akt activation and cellular consequences of 4-HNE in hepatocytes.
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Affiliation(s)
- Colin T Shearn
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Denver, Aurora, Colorado, USA
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Igal RA. Stearoyl-CoA desaturase-1: a novel key player in the mechanisms of cell proliferation, programmed cell death and transformation to cancer. Carcinogenesis 2010; 31:1509-15. [PMID: 20595235 DOI: 10.1093/carcin/bgq131] [Citation(s) in RCA: 227] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
As part of a shift toward macromolecule production to support continuous cell proliferation, cancer cells coordinate the activation of lipid biosynthesis and the signaling networks that stimulate this process. A ubiquitous metabolic event in cancer is the constitutive activation of the fatty acid biosynthetic pathway, which produces saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) to sustain the increasing demand of new membrane phospholipids with appropriate acyl composition. In cancer cells, the tandem activation of the fatty acid biosynthetic enzymes adenosine triphosphate citrate lyase, acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) leads to increased synthesis of SFA and their further conversion into MUFA by stearoyl-CoA desaturase (SCD) 1. The roles of adenosine triphosphate citrate lyase, ACC and FAS in the pathogenesis of cancer have been a subject of extensive investigation. However, despite early experimental and epidemiological observations reporting elevated levels of MUFA in cancer cells and tissues, the involvement of SCD1 in the mechanisms of carcinogenesis remains surprisingly understudied. Over the past few years, a more detailed picture of the functional relevance of SCD1 in cell proliferation, survival and transformation to cancer has begun to emerge. The present review addresses the mounting evidence that argues for a key role of SCD1 in the coordination of the intertwined pathways of lipid biosynthesis, energy sensing and the transduction signals that influence mitogenesis and tumorigenesis, as well as the potential value of this enzyme as a target for novel pharmacological approaches in cancer interventions.
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Affiliation(s)
- R Ariel Igal
- Department of Nutritional Sciences and Rutgers Center for Lipid Research, Rutgers, the State University of New Jersey, 96 Lipman Drive, New Brunswick, NJ 08901-8525, USA.
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Musso G, Gambino R, Cassader M. Emerging molecular targets for the treatment of nonalcoholic fatty liver disease. Annu Rev Med 2010; 61:375-92. [PMID: 20059344 DOI: 10.1146/annurev.med.60.101107.134820] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic fat accumulation in the absence of significant ethanol consumption, viral infection, or other specific causes of liver disease. Currently the most common chronic liver disease, affecting 30% of the Western world, NAFLD may progress to cirrhosis and end-stage liver disease and may increase the risk of developing diabetes and cardiovascular disease. Although its pathogenesis is unclear, NAFLD is tightly associated with insulin resistance and the metabolic syndrome. No established treatment exists, and current research is targeting new molecular mechanisms that underlie NAFLD and associated cardiometabolic disorders. This review discusses some of these emerging molecular mechanisms and their therapeutic implications for the treatment of NAFLD: microRNAs, incretin analogs/antagonists, liver-specific thyromimetics, AMP-activated protein kinase activators, and nuclear receptors farnesoid X receptor and pregane X receptor.
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20
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Suzuki A, Nakano T, Mak TW, Sasaki T. Portrait of PTEN: messages from mutant mice. Cancer Sci 2008; 99:209-13. [PMID: 18201277 PMCID: PMC11158684 DOI: 10.1111/j.1349-7006.2007.00670.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2007] [Accepted: 10/16/2007] [Indexed: 01/01/2023] Open
Abstract
PTEN is a tumor suppressor gene mutated in many human sporadic cancers and in hereditary cancer syndromes such as Cowden disease. The major substrate of PTEN is phosphatidylinositol-3,4,5-trisphosphate (PI(3,4,5)P3), a second messenger molecule produced following PI3K activation induced by a variety of stimuli. PI(3,4,5)P3 activates the serine-threonine kinase Akt, which is involved in antiapoptosis, proliferation and oncogenesis. In mice, heterozygosity for a null mutation of Pten (Pten(+/-)mice) frequently leads to the development of a variety of cancers and autoimmune disease. Homozygosity for the null mutation (Pten(-/-) mice) results in early embryonic lethality, precluding the functional analysis of Pten in adult tissues and organs. To investigate the physiological functions of Pten in viable mice, we and other groups have used the Cre-loxP system to generate various tissue-specific Pten mutations. The present review will summarize results obtained from the study of conditional mutant mice lacking Pten in specific tissues, and discuss the possible biological and molecular explanations for why Pten deficiency leads to tumorigenesis.
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Affiliation(s)
- Akira Suzuki
- Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan.
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21
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Yanagi S, Kishimoto H, Kawahara K, Sasaki T, Sasaki M, Nishio M, Yajima N, Hamada K, Horie Y, Kubo H, Whitsett JA, Mak TW, Nakano T, Nakazato M, Suzuki A. Pten controls lung morphogenesis, bronchioalveolar stem cells, and onset of lung adenocarcinomas in mice. J Clin Invest 2007; 117:2929-40. [PMID: 17909629 PMCID: PMC1994617 DOI: 10.1172/jci31854] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Accepted: 07/12/2007] [Indexed: 12/22/2022] Open
Abstract
PTEN is a tumor suppressor gene mutated in many human cancers. We generated a bronchioalveolar epithelium-specific null mutation of Pten in mice [SP-C-rtTA/(tetO)(7)-Cre/Pten(flox/flox) (SOPten(flox/flox)) mice] that was under the control of doxycycline. Ninety percent of SOPten(flox/flox) mice that received doxycycline in utero [SOPten(flox/flox)(E10-16) mice] died of hypoxia soon after birth. Surviving SOPten(flox/flox)(E10-16) mice and mice that received doxycycline postnatally [SOPten(flox/flox)(P21-27) mice] developed spontaneous lung adenocarcinomas. Urethane treatment accelerated number and size of lung tumors developing in SOPten(flox/flox) mice of both ages. Histological and biochemical examinations of the lungs of SOPten(flox/flox)(E10-16) mice revealed hyperplasia of bronchioalveolar epithelial cells and myofibroblast precursors, enlarged alveolar epithelial cells, and impaired production of surfactant proteins. Numbers of bronchioalveolar stem cells (BASCs), putative initiators of lung adenocarcinomas, were increased. Lungs of SOPten(flox/flox)(E10-16) mice showed increased expression of Spry2, which inhibits the maturation of alveolar epithelial cells. Levels of Akt, c-Myc, Bcl-2, and Shh were also elevated in SOPten(flox/flox)(E10-16) and SOPten(flox/flox)(P21-27) lungs. Furthermore, K-ras was frequently mutated in adenocarcinomas observed in SOPten(flox/flox)(P21-27) lungs. These results indicate that Pten is essential for both normal lung morphogenesis and the prevention of lung carcinogenesis, possibly because this tumor suppressor is required for BASC homeostasis.
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Affiliation(s)
- Shigehisa Yanagi
- Department of Molecular Biology, Akita University School of Medicine, Akita, Japan.
Division of Neurology, Respirology, Endocrinology and Metabolism, Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan.
Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Department of Microbiology and
Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
The Campbell Family Institute for Breast Cancer Research and Departments of Immunology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Department of Pathology, Medical School, and Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Hiroyuki Kishimoto
- Department of Molecular Biology, Akita University School of Medicine, Akita, Japan.
Division of Neurology, Respirology, Endocrinology and Metabolism, Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan.
Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Department of Microbiology and
Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
The Campbell Family Institute for Breast Cancer Research and Departments of Immunology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Department of Pathology, Medical School, and Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Kohichi Kawahara
- Department of Molecular Biology, Akita University School of Medicine, Akita, Japan.
Division of Neurology, Respirology, Endocrinology and Metabolism, Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan.
Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Department of Microbiology and
Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
The Campbell Family Institute for Breast Cancer Research and Departments of Immunology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Department of Pathology, Medical School, and Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Takehiko Sasaki
- Department of Molecular Biology, Akita University School of Medicine, Akita, Japan.
Division of Neurology, Respirology, Endocrinology and Metabolism, Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan.
Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Department of Microbiology and
Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
The Campbell Family Institute for Breast Cancer Research and Departments of Immunology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Department of Pathology, Medical School, and Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Masato Sasaki
- Department of Molecular Biology, Akita University School of Medicine, Akita, Japan.
Division of Neurology, Respirology, Endocrinology and Metabolism, Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan.
Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Department of Microbiology and
Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
The Campbell Family Institute for Breast Cancer Research and Departments of Immunology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Department of Pathology, Medical School, and Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Miki Nishio
- Department of Molecular Biology, Akita University School of Medicine, Akita, Japan.
Division of Neurology, Respirology, Endocrinology and Metabolism, Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan.
Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Department of Microbiology and
Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
The Campbell Family Institute for Breast Cancer Research and Departments of Immunology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Department of Pathology, Medical School, and Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Nobuyuki Yajima
- Department of Molecular Biology, Akita University School of Medicine, Akita, Japan.
Division of Neurology, Respirology, Endocrinology and Metabolism, Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan.
Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Department of Microbiology and
Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
The Campbell Family Institute for Breast Cancer Research and Departments of Immunology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Department of Pathology, Medical School, and Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Koichi Hamada
- Department of Molecular Biology, Akita University School of Medicine, Akita, Japan.
Division of Neurology, Respirology, Endocrinology and Metabolism, Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan.
Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Department of Microbiology and
Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
The Campbell Family Institute for Breast Cancer Research and Departments of Immunology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Department of Pathology, Medical School, and Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Yasuo Horie
- Department of Molecular Biology, Akita University School of Medicine, Akita, Japan.
Division of Neurology, Respirology, Endocrinology and Metabolism, Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan.
Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Department of Microbiology and
Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
The Campbell Family Institute for Breast Cancer Research and Departments of Immunology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Department of Pathology, Medical School, and Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Hiroshi Kubo
- Department of Molecular Biology, Akita University School of Medicine, Akita, Japan.
Division of Neurology, Respirology, Endocrinology and Metabolism, Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan.
Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Department of Microbiology and
Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
The Campbell Family Institute for Breast Cancer Research and Departments of Immunology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Department of Pathology, Medical School, and Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Jeffrey A. Whitsett
- Department of Molecular Biology, Akita University School of Medicine, Akita, Japan.
Division of Neurology, Respirology, Endocrinology and Metabolism, Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan.
Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Department of Microbiology and
Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
The Campbell Family Institute for Breast Cancer Research and Departments of Immunology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Department of Pathology, Medical School, and Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Tak Wah Mak
- Department of Molecular Biology, Akita University School of Medicine, Akita, Japan.
Division of Neurology, Respirology, Endocrinology and Metabolism, Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan.
Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Department of Microbiology and
Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
The Campbell Family Institute for Breast Cancer Research and Departments of Immunology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Department of Pathology, Medical School, and Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Toru Nakano
- Department of Molecular Biology, Akita University School of Medicine, Akita, Japan.
Division of Neurology, Respirology, Endocrinology and Metabolism, Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan.
Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Department of Microbiology and
Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
The Campbell Family Institute for Breast Cancer Research and Departments of Immunology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Department of Pathology, Medical School, and Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Masamitsu Nakazato
- Department of Molecular Biology, Akita University School of Medicine, Akita, Japan.
Division of Neurology, Respirology, Endocrinology and Metabolism, Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan.
Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Department of Microbiology and
Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
The Campbell Family Institute for Breast Cancer Research and Departments of Immunology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Department of Pathology, Medical School, and Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Akira Suzuki
- Department of Molecular Biology, Akita University School of Medicine, Akita, Japan.
Division of Neurology, Respirology, Endocrinology and Metabolism, Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan.
Division of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Department of Microbiology and
Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Sendai, Japan.
Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
The Campbell Family Institute for Breast Cancer Research and Departments of Immunology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Department of Pathology, Medical School, and Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
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Tremblay F, Lavigne C, Jacques H, Marette A. Role of Dietary Proteins and Amino Acids in the Pathogenesis of Insulin Resistance. Annu Rev Nutr 2007; 27:293-310. [PMID: 17666010 DOI: 10.1146/annurev.nutr.25.050304.092545] [Citation(s) in RCA: 224] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dietary proteins and amino acids are important modulators of glucose metabolism and insulin sensitivity. Although high intake of dietary proteins has positive effects on energy homeostasis by inducing satiety and possibly increasing energy expenditure, it has detrimental effects on glucose homeostasis by promoting insulin resistance and increasing gluconeogenesis. Varying the quality rather than the quantity of proteins has been shown to modulate insulin resistance induced by Western diets and has revealed that proteins derived from fish might have the most desirable effects on insulin sensitivity. In vitro and in vivo data also support an important role of amino acids in glucose homeostasis through modulation of insulin action on muscle glucose transport and hepatic glucose production, secretion of insulin and glucagon, as well as gene and protein expression in various tissues. Moreover, amino acid signaling is integrated by mammalian target of rapamycin, a nutrient sensor that operates a negative feedback loop toward insulin receptor substrate 1 signaling, promoting insulin resistance for glucose metabolism. This integration suggests that modulating dietary proteins and the flux of circulating amino acids generated by their consumption and digestion might underlie powerful new approaches to treat various metabolic diseases such as obesity and diabetes.
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Affiliation(s)
- Frédéric Tremblay
- Department of Anatomy & Physiology and Lipid Research Unit, Laval University Hospital Research Center, Québec, Canada
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Caldwell SH, Ikura Y, Iezzoni JC, Liu Z. Has natural selection in human populations produced two types of metabolic syndrome (with and without fatty liver)? J Gastroenterol Hepatol 2007; 22 Suppl 1:S11-9. [PMID: 17567458 DOI: 10.1111/j.1440-1746.2006.04639.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Fatty liver is closely related to the development of the insulin resistance syndrome that largely results from abnormal insulin signaling in three major organs: (i) skeletal muscle in which insulin sensitivity depends on fat content and metabolic activity (exercise); (ii) adipose tissue, which serves as a reservoir of energy in the form of triglycerides; and (iii) the liver, which variably serves as a source or storage site of carbohydrates and lipids. In many respects, the fatty liver resembles a mixture of brown adipose tissue (microvesicular steatosis) and white adipose tissue (macrovesicular steatosis) including the stages of fatty droplet accumulation, and the expression of uncoupling proteins and perilipin-like substances. Furthermore, the development of an inflammatory infiltrate and the increased production of cytokines as occurs in adipose tissue, suggest that the liver in some individuals serves as an extension of adipose tissue. Moreover, current evidence indicates that these morphological changes represent altered gene expression similar to that of adipocytes. However, fatty liver does not appear to be a uniform feature of the metabolic syndrome and there is substantial variation in humans in the development of fatty liver independent of insulin resistance. In this regard, the variable development of fatty liver in Palmipedes (migratory fowl) and its close relationship to skeletal muscle utilization of fatty acids, lipoprotein metabolism and thermoregulation are instructive. The predilection to non-alcoholic fatty liver disease among some varieties of Palmipedes suggests that the development of fatty liver represents an adaptive process, closely integrated with skeletal muscle fat utilization and adipose tissue distribution, and facilitates survival in a very cold, resource-scarce environment. Variation in human populations with metabolic syndrome likewise suggests that the trait evolved in populations exposed in ancient times to different environmental challenges and, because the liver plays a central role in lipid metabolism, the presence or absence of fatty liver is likely to be integrated with insulin sensitivity in other target organs and with lipoprotein metabolism.
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Affiliation(s)
- Stephen H Caldwell
- Division of GI/Hepatology, Digestive Health Center of Excellence, University of Virginia, Charlottesville, Virginia 22908-0708, USA.
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Watanabe S, Horie Y, Kataoka E, Sato W, Dohmen T, Ohshima S, Goto T, Suzuki A. Non-alcoholic steatohepatitis and hepatocellular carcinoma: lessons from hepatocyte-specific phosphatase and tensin homolog (PTEN)-deficient mice. J Gastroenterol Hepatol 2007; 22 Suppl 1:S96-S100. [PMID: 17567478 DOI: 10.1111/j.1440-1746.2006.04665.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Non-alcoholic steatohepatitis (NASH) is a term used to describe a spectrum of conditions characterized by histological findings of hepatic macrovesicular steatosis with inflammation in individuals who consume little or no alcohol. The NASH patients progress to liver cirrhosis and even hepatocellular carcinoma (HCC). Hepatocyte-specific phosphatase and tensin homolog (PTEN)-deficient mice (PTEN-deficient mice), which the authors had generated previously, showed massive hepatomegaly and steatohepatitis with triglyceride accumulation followed by liver fibrosis and HCC, a phenotype similar to human NASH. Therefore, it was shown that PTEN deficiency in hepatocytes could induce hepatic steatosis, inflammation, fibrosis and tumors and that PTEN-deficient mice were a useful animal model for not only the understanding of the pathogenesis of NASH but also the development of treatment for NASH.
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Affiliation(s)
- Sumio Watanabe
- Department of Gastroenterology, Akita School of Medicine, Akia, Japan.
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Wang L, Wang WL, Zhang Y, Guo SP, Zhang J, Li QL. Epigenetic and genetic alterations of PTEN in hepatocellular carcinoma. Hepatol Res 2007; 37:389-96. [PMID: 17441812 DOI: 10.1111/j.1872-034x.2007.00042.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
AIM To investigate the roles of epigenetic and genetic alterations of the phosphatase and tensin homologue on chromosome 10 gene (PTEN) in carcinogenesis and the development of hepatocellular carcinomas (HCC). METHODS A total of 56 cases of HCC tissues and six liver cell lines were studied for the expression of PTEN by immunohistochemistry and Western blot analysis. The PTEN gene mutations in exon5 and exon8 were detected by a combination of single-strand conformation polymorphism (SSCP) analysis and DNA sequencing. Methylation-specific PCR (MSP) was used to identify PTEN promoter methylation. RESULTS Of the 56 cases of HCC, 24 (42.9%) expressed the PTEN protein. All surrounding liver tissues of the hepatoma (32 cases) were positive for PTEN. Of the six cell lines, three liver cancer cell lines showed a low expression of PTEN. Five mutations of 56 HCC samples were detected. All of them were located at intron4. No mutation was found in exon5 and exon8. After MSP analysis, we found nine cases of PTEN promoter methylation in 56 specimens (16.1%). However, no CpG island of PTEN was found to be methylated in all six liver cell lines. CONCLUSION The level of PTEN protein was altered in part of the HCC. The downregulation of PTEN expression may not be mainly associated with the PTEN mutations, but partly due to PTEN promoter methylation and other epigenetic regulation.
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Affiliation(s)
- Li Wang
- Department of Pathology, Xijing Hospital, State Key Laboratory of Cancer Biology, Fourth Military Medical University, Xi’an, China
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Abstract
BACKGROUND/AIMS Dysregulation of the balance between proliferation and cell death represents a protumorigenic principle in human hepatocarcinogenesis. This article aims to provide a review of the current findings about how physiological hepatocyte apoptosis is regulated and whether or not its dysregulation might contribute to the progression towards a hepatocellular carcinoma (HCC) process. RESULTS Although some physiological proapoptotic molecules are downregulated or inactivated in HCC, such as Fas, p53, Bax or Bid, dysregulation of the balance between death and survival is mainly due to overactivation of antiapoptotic signals. Thus, some growth factors that mediate cell survival are upregulated in HCC, as well as the molecules involved in the machinery responsible for cleavage of their proforms to an active peptide. The expression of the pten gene is reduced or absent in almost half the HCCs and the Spred family of Ras/ERK inhibitors is also dysregulated in HCC, which consequently lead to the overactivation of relevant survival kinases: AKT and ERKs. Alterations in the expression and/or activity of molecules involved in counteracting apoptosis, such as NF-kappaB, Bcl-X(L), Mcl-1 or c-IAP1, have also been observed in HCC. CONCLUSIONS Therefore, therapeutic strategies to inhibit selectively antiapoptotic signals in tumour cells have the potential to provide powerful tools to treat liver cancer.
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Affiliation(s)
- Isabel Fabregat
- Institut de Investigació Biomèdica de Bellvitge, Institut de Recerca Oncològica, L'Hospitalet, Barcelona, Spain.
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