RESUMO
Nonalcoholic steatohepatitis (NASH) is the most prevalent cause of chronic liver disease in the Western world. However, an optimum therapy for NASH is yet to be established, mandating more in-depth investigation into the molecular pathogenesis of NASH to identify novel regulatory molecules and develop targeted therapies. Here, we unravel a unique function of astrocyte elevated gene-1(AEG-1)/metadherin in NASH using a transgenic mouse with hepatocyte-specific overexpression of AEG-1 (Alb/AEG-1) and a conditional hepatocyte-specific AEG-1 knockout mouse (AEG-1ΔHEP ). Alb/AEG-1 mice developed spontaneous NASH whereas AEG-1ΔHEP mice were protected from high-fat diet (HFD)-induced NASH. Intriguingly, AEG-1 overexpression was observed in livers of NASH patients and wild-type (WT) mice that developed steatosis upon feeding HFD. In-depth molecular analysis unraveled that inhibition of peroxisome proliferator-activated receptor alpha activity resulting in decreased fatty acid ß-oxidation, augmentation of translation of fatty acid synthase resulting in de novo lipogenesis, and increased nuclear factor kappa B-mediated inflammation act in concert to mediate AEG-1-induced NASH. Therapeutically, hepatocyte-specific nanoparticle-delivered AEG-1 small interfering RNA provided marked protection from HFD-induced NASH in WT mice. CONCLUSION: AEG-1 might be a key molecule regulating initiation and progression of NASH. AEG-1 inhibitory strategies might be developed as a potential therapeutic intervention in NASH patients. (Hepatology 2017;66:466-480).
Assuntos
Regulação da Expressão Gênica , Glicoproteínas de Membrana/genética , Hepatopatia Gordurosa não Alcoólica/genética , Hepatopatia Gordurosa não Alcoólica/patologia , PPAR alfa/metabolismo , Análise de Variância , Animais , Biópsia por Agulha , Células Cultivadas , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Hepatócitos/citologia , Hepatócitos/metabolismo , Humanos , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos CBA , Camundongos Transgênicos , Distribuição Aleatória , Papel (figurativo)RESUMO
Staphylococcal nuclease and tudor domain containing 1 (SND1) is overexpressed in multiple cancers, including hepatocellular carcinoma (HCC), and functions as an oncogene. This study was carried out to identify novel SND1-interacting proteins to better understand its molecular mechanism of action. SND1-interacting proteins were identified by a modified yeast two-hybrid assay. Protein-protein interaction was confirmed by co-immunoprecipitation analysis. Monoglyceride lipase (MGLL) expression was analyzed by quantitative RT-PCR, Western blot, and immunohistochemistry. MGLL-overexpressing clones were analyzed for cell proliferation and cell cycle analysis and in vivo tumorigenesis in nude mice. MGLL was identified as an SND1-interacting protein. Interaction of SND1 with MGLL resulted in ubiquitination and proteosomal degradation of MGLL. MGLL expression was detected in normal human hepatocytes and mouse liver, although it was undetected in human HCC cell lines. An inverse correlation between SND1 and MGLL levels was identified in a human HCC tissue microarray as well as in the TCGA database. Forced overexpression of MGLL in human HCC cells resulted in marked inhibition in cell proliferation with a significant delay in cell cycle progression and a marked decrease in tumor growth in nude mouse xenograft assays. MGLL overexpression inhibited Akt activation that is independent of enzymatic activity of MGLL and overexpression of a constitutively active Akt rescued cells from inhibition of proliferation and restored normal cell cycle progression. This study unravels a novel mechanism of SND1 function and identifies MGLL as a unique tumor suppressor for HCC. MGLL might function as a homeostatic regulator of Akt restraining its activation.
Assuntos
Carcinoma Hepatocelular/metabolismo , Ciclo Celular , Transformação Celular Neoplásica/metabolismo , Neoplasias Hepáticas/metabolismo , Monoacilglicerol Lipases/metabolismo , Proteínas Nucleares/metabolismo , Proteólise , Proteínas Supressoras de Tumor/metabolismo , Animais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/patologia , Endonucleases , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Camundongos , Camundongos Nus , Monoacilglicerol Lipases/genética , Proteínas Nucleares/genética , Proteínas Proto-Oncogênicas c-akt/biossíntese , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Supressoras de Tumor/genética , Ubiquitinação/genéticaRESUMO
Non-thyroidal illness syndrome (NTIS), characterized by low serum 3,5,3'-triiodothyronine (T3) with normal l-thyroxine (T4) levels, is associated with malignancy. Decreased activity of type I 5'-deiodinase (DIO1), which converts T4 to T3, contributes to NTIS. T3 binds to thyroid hormone receptor, which heterodimerizes with retinoid X receptor (RXR) and regulates transcription of target genes, such as DIO1. NF-κB activation by inflammatory cytokines inhibits DIO1 expression. The oncogene astrocyte elevated gene-1 (AEG-1) inhibits RXR-dependent transcription and activates NF-κB. Here, we interrogated the role of AEG-1 in NTIS in the context of hepatocellular carcinoma (HCC). T3-mediated gene regulation was analyzed in human HCC cells, with overexpression or knockdown of AEG-1, and primary hepatocytes from AEG-1 transgenic (Alb/AEG-1) and AEG-1 knock-out (AEG-1KO) mice. Serum T3 and T4 levels were checked in Alb/AEG-1 mice and human HCC patients. AEG-1 and DIO1 levels in human HCC samples were analyzed by immunohistochemistry. AEG-1 inhibited T3-mediated gene regulation in human HCC cells and mouse hepatocytes. AEG-1 overexpression repressed and AEG-1 knockdown induced DIO1 expression. An inverse correlation was observed between AEG-1 and DIO1 levels in human HCC patients. Low T3 with normal T4 was observed in the sera of HCC patients and Alb/AEG-1 mice. Inhibition of co-activator recruitment to RXR and activation of NF-κB were identified to play a role in AEG-1-mediated down-regulation of DIO1. AEG-1 thus might play a role in NTIS associated with HCC and other cancers.
Assuntos
Carcinoma Hepatocelular/metabolismo , Moléculas de Adesão Celular/metabolismo , Síndromes do Eutireóideo Doente/metabolismo , Neoplasias Hepáticas/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas de Neoplasias/metabolismo , Animais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Moléculas de Adesão Celular/genética , Linhagem Celular Tumoral , Regulação para Baixo/genética , Síndromes do Eutireóideo Doente/etiologia , Síndromes do Eutireóideo Doente/genética , Regulação Enzimológica da Expressão Gênica/genética , Regulação Neoplásica da Expressão Gênica/genética , Células HEK293 , Hepatócitos/metabolismo , Hepatócitos/patologia , Humanos , Iodeto Peroxidase/biossíntese , Iodeto Peroxidase/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Glicoproteínas de Membrana/genética , Proteínas de Membrana , Camundongos , Camundongos Knockout , NF-kappa B/genética , NF-kappa B/metabolismo , Proteínas de Neoplasias/genética , Proteínas de Ligação a RNA , Receptores X de Retinoides/genética , Receptores X de Retinoides/metabolismo , Tri-Iodotironina/genética , Tri-Iodotironina/metabolismoRESUMO
Astrocyte elevated gene-1 (AEG-1), also known as MTDH (metadherin) or LYRIC, is an established oncogene. However, the physiological function of AEG-1 is not known. To address this question, we generated an AEG-1 knock-out mouse (AEG-1KO) and characterized it. Although AEG-1KO mice were viable and fertile, they were significantly leaner with prominently less body fat and lived significantly longer compared with wild type (WT). When fed a high fat and cholesterol diet (HFD), WT mice rapidly gained weight, whereas AEG-1KO mice did not gain weight at all. This phenotype of AEG-1KO mice is due to decreased fat absorption from the intestines, not because of decreased fat synthesis or increased fat consumption. AEG-1 interacts with retinoid X receptor (RXR) and inhibits RXR function. In enterocytes of AEG-1KO mice, we observed increased activity of RXR heterodimer partners, liver X receptor and peroxisome proliferator-activated receptor-α, key inhibitors of intestinal fat absorption. Inhibition of fat absorption in AEG-1KO mice was further augmented when fed an HFD providing ligands to liver X receptor and peroxisome proliferator-activated receptor-α. Our studies reveal a novel role of AEG-1 in regulating nuclear receptors controlling lipid metabolism. AEG-1 may significantly modulate the effects of HFD and thereby function as a unique determinant of obesity.
Assuntos
Mucosa Intestinal/metabolismo , Metabolismo dos Lipídeos , Fígado/metabolismo , Proteínas de Membrana/metabolismo , Aumento de Peso , Tecido Adiposo/metabolismo , Animais , Homeostase , Receptores X do Fígado , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade/genética , Obesidade/metabolismo , Receptores Nucleares Órfãos/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/metabolismo , Proteínas de Ligação a RNA , Receptores X de Retinoides/metabolismoRESUMO
UNLABELLED: Astrocyte elevated gene-1 (AEG-1) and c-Myc are overexpressed in human hepatocellular carcinoma (HCC) functioning as oncogenes. AEG-1 is transcriptionally regulated by c-Myc, and AEG-1 itself induces c-Myc by activating the Wnt/ß-catenin-signaling pathway. We now document the cooperation of AEG-1 and c-Myc in promoting hepatocarcinogenesis by analyzing hepatocyte-specific transgenic mice expressing either AEG-1 (albumin [Alb]/AEG-1), c-Myc (Alb/c-Myc), or both (Alb/AEG-1/c-Myc). Wild-type and Alb/AEG-1 mice did not develop spontaneous HCC. Alb/c-Myc mice developed spontaneous HCC without distant metastasis, whereas Alb/AEG-1/c-Myc mice developed highly aggressive HCC with frank metastasis to the lungs. Induction of carcinogenesis by N-nitrosodiethylamine significantly accelerated the kinetics of tumor formation in all groups. However, in Alb/AEG-1/c-Myc, the effect was markedly pronounced with lung metastasis. In vitro analysis showed that Alb/AEG-1/c-Myc hepatocytes acquired increased proliferation and transformative potential with sustained activation of prosurvival and epithelial-mesenchymal transition-signaling pathways. RNA-sequencing analysis identified a unique gene signature in livers of Alb/AEG-1/c-Myc mice that was not observed when either AEG-1 or c-Myc was overexpressed. Specifically, Alb/AEG-1/c-Myc mice overexpressed maternally imprinted noncoding RNAs (ncRNAs), such as Rian, Meg-3, and Mirg, which are implicated in hepatocarcinogenesis. Knocking down these ncRNAs significantly inhibited proliferation and invasion by Alb/AEG-1/c-Myc hepatocytes. CONCLUSION: Our studies reveal a novel cooperative oncogenic effect of AEG-1 and c-Myc that might explain the mechanism of aggressive HCC. Alb/AEG-1/c-Myc mice provide a useful model to understand the molecular mechanism of cooperation between these two oncogenes and other molecules involved in hepatocarcinogenesis. This model might also be of use for evaluating novel therapeutic strategies targeting HCC.
Assuntos
Neoplasias Hepáticas Experimentais/etiologia , Proteínas de Membrana/fisiologia , Proteínas Proto-Oncogênicas c-myc/fisiologia , Albuminas/análise , Animais , Carcinogênese , Células Cultivadas , Transição Epitelial-Mesenquimal , Neoplasias Hepáticas Experimentais/patologia , Neoplasias Pulmonares/secundário , Proteínas de Membrana/análise , Camundongos , Camundongos Transgênicos , Proteínas Proto-Oncogênicas c-myc/análise , Proteínas de Ligação a RNARESUMO
Hepatocellular carcinoma (HCC) is a fatal cancer with no effective therapy. Astrocyte elevated gene-1 (AEG-1) plays a pivotal role in hepatocarcinogenesis and inhibits retinoic acid-induced gene expression and cell death. The combination of a lentivirus expressing AEG-1 shRNA and all-trans retinoic acid (ATRA) profoundly and synergistically inhibited subcutaneous human HCC xenografts in nude mice. We have now developed liver-targeted nanoplexes by conjugating poly(amidoamine) (PAMAM) dendrimers with polyethylene glycol (PEG) and lactobionic acid (Gal) (PAMAM-PEG-Gal) which were complexed with AEG-1 siRNA (PAMAM-AEG-1si). The polymer conjugate was characterized by (1)H-NMR, MALDI, and mass spectrometry; and optimal nanoplex formulations were characterized for surface charge, size, and morphology. Orthotopic xenografts of human HCC cell QGY-7703 expressing luciferase (QGY-luc) were established in the livers of athymic nude mice and tumor development was monitored by bioluminescence imaging (BLI). Tumor-bearing mice were treated with PAMAM-siCon, PAMAM-siCon+ATRA, PAMAM-AEG-1si, and PAMAM-AEG-1si+ATRA. In the control group the tumor developed aggressively. ATRA showed little effect due to high AEG-1 levels in QGY-luc cells. PAMAM-AEG-1si showed significant reduction in tumor growth, and the combination of PAMAM-AEG-1si+ATRA showed profound and synergistic inhibition so that the tumors were almost undetectable by BLI. A marked decrease in AEG-1 level was observed in tumor samples treated with PAMAM-AEG-1si. The group treated with PAMAM-AEG-1si+ATRA nanoplexes showed increased necrosis, inhibition of proliferation, and increased apoptosis when compared to other groups. Liver is an ideal organ for RNAi therapy and ATRA is an approved anticancer agent. Our exciting observations suggest that the combinatorial approach might be an effective way to combat HCC.
Assuntos
Carcinoma Hepatocelular/terapia , Moléculas de Adesão Celular/antagonistas & inibidores , Neoplasias Hepáticas/terapia , Nanopartículas/administração & dosagem , RNA Interferente Pequeno/genética , Tretinoína/farmacologia , Animais , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Moléculas de Adesão Celular/genética , Proliferação de Células/efeitos dos fármacos , Terapia Combinada , Terapia Genética , Humanos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Proteínas de Membrana , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Nus , Nanopartículas/química , Proteínas de Ligação a RNA , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Hepatocellular carcinoma (HCC) is a highly fatal disease mandating development of novel, targeted therapies to elicit prolonged survival benefit to the patients. Insulin-like growth factor-binding protein-7 (IGFBP7), a secreted protein belonging to the IGFBP family, functions as a potential tumor suppressor for HCC. In the present study, we evaluated the therapeutic efficacy of a replication-incompetent adenovirus expressing IGFBP7 (Ad.IGFBP7) in human HCC. Ad.IGFBP7 profoundly inhibited viability and induced apoptosis in multiple human HCC cell lines by inducing reactive oxygen species (ROS) and activating a DNA damage response (DDR) and p38 MAPK. In orthotopic xenograft models of human HCC in athymic nude mice, intravenous administration of Ad.IGFBP7 profoundly inhibited primary tumor growth and intrahepatic metastasis. In a nude mice subcutaneous model, xenografts from human HCC cells were established in both flanks and only left-sided tumors received intratumoral injection of Ad.IGFBP7. Growth of both left-sided injected tumors and right-sided uninjected tumors were markedly inhibited by Ad.IGFBP7 with profound suppression of angiogenesis. These findings indicate that Ad.IGFBP7 might be a potent therapeutic eradicating both primary HCC and distant metastasis and might be an effective treatment option for terminal HCC patients.
Assuntos
Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/terapia , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/metabolismo , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/terapia , Adenoviridae/genética , Animais , Carcinoma Hepatocelular/genética , Humanos , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/genética , Neoplasias Hepáticas/genética , Masculino , Camundongos , Camundongos Nus , Espécies Reativas de Oxigênio/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
UNLABELLED: Astrocyte elevated gene-1 (AEG-1) is a key contributor to hepatocellular carcinoma (HCC) development and progression. To enhance our understanding of the role of AEG-1 in hepatocarcinogenesis, a transgenic mouse with hepatocyte-specific expression of AEG-1 (Alb/AEG1) was developed. Treating Alb/AEG-1, but not wild-type (WT) mice, with N-nitrosodiethylamine resulted in multinodular HCC with steatotic features and associated modulation of expression of genes regulating invasion, metastasis, angiogenesis, and fatty acid synthesis. Hepatocytes isolated from Alb/AEG-1 mice displayed profound resistance to chemotherapeutics and growth factor deprivation with activation of prosurvival signaling pathways. Alb/AEG-1 hepatocytes also exhibited marked resistance toward senescence, which correlated with abrogation of activation of a DNA damage response. Conditioned media from Alb/AEG-1 hepatocytes induced marked angiogenesis with elevation in several coagulation factors. Among these factors, AEG-1 facilitated the association of factor XII (FXII) messenger RNA with polysomes, resulting in increased translation. Short interfering RNA-mediated knockdown of FXII resulted in profound inhibition of AEG-1-induced angiogenesis. CONCLUSION: We uncovered novel aspects of AEG-1 functions, including induction of steatosis, inhibition of senescence, and activation of the coagulation pathway to augment aggressive hepatocarcinogenesis. The Alb/AEG-1 mouse provides an appropriate model to scrutinize the molecular mechanism of hepatocarcinogenesis and to evaluate the efficacy of novel therapeutic strategies targeting HCC.
Assuntos
Carcinoma Hepatocelular/genética , Moléculas de Adesão Celular/genética , Transformação Celular Neoplásica/genética , Modelos Animais de Doenças , Neoplasias Hepáticas/genética , Neovascularização Patológica/genética , Animais , Antineoplásicos/farmacologia , Carcinoma Hepatocelular/induzido quimicamente , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Moléculas de Adesão Celular/metabolismo , Células Cultivadas , Senescência Celular/genética , Dietilnitrosamina , Doxorrubicina/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , Fator XII/genética , Fator XII/metabolismo , Ácidos Graxos/biossíntese , Fígado Gorduroso/genética , Fígado Gorduroso/patologia , Fluoruracila/farmacologia , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Fígado/irrigação sanguínea , Fígado/metabolismo , Fígado/patologia , Neoplasias Hepáticas/induzido quimicamente , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Masculino , Proteínas de Membrana , Camundongos , Camundongos Transgênicos , Invasividade Neoplásica/genética , Metástase Neoplásica , Análise de Sequência com Séries de Oligonucleotídeos , Polirribossomos , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNARESUMO
Chronic inflammation is a known hallmark of cancer and is central to the onset and progression of hepatocellular carcinoma (HCC). Hepatic macrophages play a critical role in the inflammatory process leading to HCC. The oncogene Astrocyte elevated gene-1 (AEG-1) regulates NFκB activation, and germline knockout of AEG-1 in mice (AEG-1-/-) results in resistance to inflammation and experimental HCC. In this study, we developed conditional hepatocyte- and myeloid cell-specific AEG-1-/- mice (AEG-1ΔHEP and AEG-1ΔMAC, respectively) and induced HCC by treatment with N-nitrosodiethylamine (DEN) and phenobarbital (PB). AEG-1ΔHEP mice exhibited a significant reduction in disease severity compared with control littermates, while AEG-1ΔMAC mice were profoundly resistant. In vitro, AEG-1-/- hepatocytes exhibited increased sensitivity to stress and senescence. Notably, AEG-1-/- macrophages were resistant to either M1 or M2 differentiation with significant inhibition in migration, endothelial adhesion, and efferocytosis activity, indicating that AEG-1 ablation renders macrophages functionally anergic. These results unravel a central role of AEG-1 in regulating macrophage activation and indicate that AEG-1 is required in both tumor cells and tumor microenvironment to stimulate hepatocarcinogenesis.Significance: These findings distinguish a novel role of macrophage-derived oncogene AEG-1 from hepatocellular AEG-1 in promoting inflammation and driving tumorigenesis. Cancer Res; 78(22); 6436-46. ©2018 AACR.
Assuntos
Carcinoma Hepatocelular/metabolismo , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/metabolismo , Macrófagos/metabolismo , Proteínas de Membrana/metabolismo , Animais , Adesão Celular , Diferenciação Celular , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Quimiotaxia , Dietilnitrosamina , Hepatócitos/citologia , Hepatócitos/metabolismo , Inflamação , Macrófagos/citologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Fenobarbital , RNA Interferente Pequeno/metabolismo , Proteínas de Ligação a RNA , Fatores de Risco , Microambiente TumoralRESUMO
SND1, a subunit of the miRNA regulatory complex RISC, has been implicated as an oncogene in hepatocellular carcinoma (HCC). In this study, we show that hepatocyte-specific SND1 transgenic mice (Alb/SND1 mice) develop spontaneous HCC with partial penetrance and exhibit more highly aggressive HCC induced by chemical carcinogenesis. Livers from Alb/SND1 mice exhibited a relative increase in inflammatory markers and spheroid-generating tumor-initiating cells (TIC). Mechanistic investigations defined roles for Akt and NF-κB signaling pathways in promoting TIC formation in Alb/SND1 mice. In human xenograft models of subcutaneous or orthotopic HCC, administration of the selective SND1 inhibitor 3', 5'-deoxythymidine bisphosphate (pdTp), inhibited tumor formation without effects on body weight or liver function. Our work establishes an oncogenic role for SND1 in promoting TIC formation and highlights pdTp as a highly selective SND1 inhibitor as a candidate therapeutic lead to treat advanced HCC. Cancer Res; 77(12); 3306-16. ©2017 AACR.
Assuntos
Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Células-Tronco Neoplásicas/patologia , Proteínas Nucleares/metabolismo , Proteínas Oncogênicas/metabolismo , Animais , Antineoplásicos/farmacologia , Western Blotting , Transformação Celular Neoplásica/genética , Modelos Animais de Doenças , Progressão da Doença , Endonucleases , Citometria de Fluxo , Imunofluorescência , Humanos , Imuno-Histoquímica , Camundongos , Camundongos Transgênicos , Reação em Cadeia da Polimerase , Nucleotídeos de Timina/farmacologiaRESUMO
Activation of IGF signaling is a major oncogenic event in diverse cancers, including hepatocellular carcinoma (HCC). In this setting, the insulin-like growth factor binding protein IGFBP7 inhibits IGF signaling by binding the IGF1 receptor (IGF1R), functioning as a candidate tumor suppressor. IGFBP7 abrogates tumors by inhibiting angiogenesis and inducing cancer-specific senescence and apoptosis. Here, we report that Igfbp7-deficient mice exhibit constitutively active IGF signaling, presenting with proinflammatory and immunosuppressive microenvironments and spontaneous liver and lung tumors occurring with increased incidence in carcinogen-treated subjects. Igfbp7 deletion increased proliferation and decreased senescence of hepatocytes and mouse embryonic fibroblasts, effects that were blocked by treatment with IGF1 receptor inhibitor. Significant inhibition of genes regulating immune surveillance was observed in Igfbp7-/- murine livers, which was associated with a marked inhibition in antigen cross-presentation by Igfbp7-/- dendritic cells. Conversely, IGFBP7 overexpression inhibited growth of HCC cells in syngeneic immunocompetent mice. Depletion of CD4+ or CD8+ T lymphocytes abolished this growth inhibition, identifying it as an immune-mediated response. Our findings define an immune component of the pleiotropic mechanisms through which IGFBP7 suppresses HCC. Furthermore, they offer a genetically based preclinical proof of concept for IGFBP7 as a therapeutic target for immune management of HCC. Cancer Res; 77(15); 4014-25. ©2017 AACR.
Assuntos
Carcinoma Hepatocelular/patologia , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/deficiência , Neoplasias Hepáticas/patologia , Animais , Western Blotting , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/imunologia , Modelos Animais de Doenças , Citometria de Fluxo , Imunofluorescência , Imuno-Histoquímica , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/genética , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/imunologia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos SCID , Reação em Cadeia da Polimerase em Tempo RealRESUMO
AEG-1 is an oncogene that is overexpressed in all cancers, including hepatocellular carcinoma. AEG-1 plays a seminal role in promoting cancer development and progression by augmenting proliferation, invasion, metastasis, angiogenesis and chemoresistance, all hallmarks of aggressive cancer. AEG-1 mediates its oncogenic function predominantly by interacting with various protein complexes. AEG-1 acts as a scaffold protein, activating multiple protumorigenic signal transduction pathways, such as MEK/ERK, PI3K/Akt, NF-κB and Wnt/ß-catenin while regulating gene expression at transcriptional, post-transcriptional and translational levels. Our recent studies document that AEG-1 is fundamentally required for activation of inflammation. A comprehensive and convincing body of data currently points to AEG-1 as an essential component critical to the onset and progression of cancer. The present review describes the current knowledge gleaned from patient and experimental studies as well as transgenic and knockout mouse models, on the impact of AEG-1 on hepatocarcinogenesis.
RESUMO
The staphylococcal nuclease and tudor domain containing 1 (SND1) is a multifunctional protein overexpressed in breast, prostate, colorectal and hepatocellular carcinomas and malignant glioma. Molecular studies have revealed the multifaceted activities of SND1 involved in regulating gene expression at transcriptional as well as post-transcriptional levels. Early studies identified SND1 as a transcriptional co-activator. SND1 is also a component of RNA-induced silencing complex (RISC) thus mediating RNAi function, a regulator of mRNA splicing, editing and stability, and plays a role in maintenance of cell viability. Such diverse actions allow the SND1 to modulate a complex array of molecular networks, thereby promoting carcinogenesis. Here, we describe the crucial role of SND1 in cancer development and progression, and highlight SND1 as a potential target for therapeutic intervention.
Assuntos
Transformação Celular Neoplásica/genética , Regulação Neoplásica da Expressão Gênica/genética , Neoplasias/genética , Proteínas Nucleares/genética , Carboxipeptidases/genética , Endonucleases , Humanos , Terapia de Alvo Molecular , Neoplasias/patologia , Proteínas Nucleares/biossíntese , Interferência de RNA , Splicing de RNA/genéticaRESUMO
Hepatocellular carcinoma (HCC) is a lethal malignancy with high mortality and poor prognosis. Oncogenic transcription factor Late SV40 Factor (LSF) plays an important role in promoting HCC. A small molecule inhibitor of LSF, Factor Quinolinone Inhibitor 1 (FQI1), significantly inhibited human HCC xenografts in nude mice without harming normal cells. Here we evaluated the efficacy of FQI1 and another inhibitor, FQI2, in inhibiting endogenous hepatocarcinogenesis. HCC was induced in a transgenic mouse with hepatocyte-specific overexpression of c-myc (Alb/c-myc) by injecting N-nitrosodiethylamine (DEN) followed by FQI1 or FQI2 treatment after tumor development. LSF inhibitors markedly decreased tumor burden in Alb/c-myc mice with a corresponding decrease in proliferation and angiogenesis. Interestingly, in vitro treatment of human HCC cells with LSF inhibitors resulted in mitotic arrest with an accompanying increase in CyclinB1. Inhibition of CyclinB1 induction by Cycloheximide or CDK1 activity by Roscovitine significantly prevented FQI-induced mitotic arrest. A significant induction of apoptosis was also observed upon treatment with FQI. These effects of LSF inhibition, mitotic arrest and induction of apoptosis by FQI1s provide multiple avenues by which these inhibitors eliminate HCC cells. LSF inhibitors might be highly potent and effective therapeutics for HCC either alone or in combination with currently existing therapies.
Assuntos
Antineoplásicos/farmacologia , Benzodioxóis/farmacologia , Carcinoma Hepatocelular/tratamento farmacológico , Proteínas de Ligação a DNA/antagonistas & inibidores , Neoplasias Hepáticas Experimentais/tratamento farmacológico , Quinolonas/farmacologia , Fatores de Transcrição/antagonistas & inibidores , Animais , Apoptose/efeitos dos fármacos , Carcinoma Hepatocelular/induzido quimicamente , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proteínas de Ligação a DNA/metabolismo , Dietilnitrosamina , Relação Dose-Resposta a Droga , Genes myc , Predisposição Genética para Doença , Humanos , Neoplasias Hepáticas Experimentais/induzido quimicamente , Neoplasias Hepáticas Experimentais/genética , Neoplasias Hepáticas Experimentais/metabolismo , Neoplasias Hepáticas Experimentais/patologia , Camundongos Transgênicos , Mitose/efeitos dos fármacos , Terapia de Alvo Molecular , Neovascularização Patológica , Fenótipo , Transdução de Sinais/efeitos dos fármacos , Fatores de Tempo , Fatores de Transcrição/metabolismoRESUMO
Staphylococcal nuclease domain containing-1 (SND1) is overexpressed in human hepatocellular carcinoma (HCC) patients and promotes tumorigenesis by human HCC cells. We now document that SND1 increases angiotensin II type 1 receptor (AT1R) levels by increasing AT1R mRNA stability. This results in activation of ERK, Smad2 and subsequently the TGFß signaling pathway, promoting epithelial-mesenchymal transition (EMT) and migration and invasion by human HCC cells. A positive correlation was observed between SND1 and AT1R expression levels in human HCC patients. Small molecule inhibitors of SND1, alone or in combination with AT1R blockers, might be an effective therapeutic strategy for late-stage aggressive HCC.
RESUMO
Activation of the oncogene AEG-1 (MTDH, LYRIC) has been implicated recently in the development of hepatocellular carcinoma (HCC). In mice, HCC can be initiated by exposure to the carcinogen DEN, which has been shown to rely upon activation of NF-κB in liver macrophages. Because AEG-1 is an essential component of NF-κB activation, we interrogated the susceptibility of mice lacking the AEG-1 gene to DEN-induced hepatocarcinogenesis. AEG-1-deficient mice displayed resistance to DEN-induced HCC and lung metastasis. No difference was observed in the response to growth factor signaling or activation of AKT, ERK, and ß-catenin, compared with wild-type control animals. However, AEG-1-deficient hepatocytes and macrophages exhibited a relative defect in NF-κB activation. Mechanistic investigations showed that IL6 production and STAT3 activation, two key mediators of HCC development, were also deficient along with other biologic and epigenetics findings in the tumor microenvironment, confirming that AEG-1 supports an NF-κB-mediated inflammatory state that drives HCC development. Overall, our findings offer in vivo proofs that AEG-1 is essential for NF-κB activation and hepatocarcinogenesis, and they reveal new roles for AEG-1 in shaping the tumor microenvironment for HCC development.
Assuntos
Carcinoma Hepatocelular/genética , Moléculas de Adesão Celular/genética , Neoplasias Hepáticas/genética , Neoplasias Experimentais/genética , Animais , Carcinogênese/genética , Carcinoma Hepatocelular/induzido quimicamente , Carcinoma Hepatocelular/patologia , Resistencia a Medicamentos Antineoplásicos/genética , Deleção de Genes , Regulação Neoplásica da Expressão Gênica , Hepatócitos/metabolismo , Hepatócitos/patologia , Humanos , Neoplasias Hepáticas/induzido quimicamente , Neoplasias Hepáticas/patologia , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/secundário , Proteínas de Membrana , Camundongos , NF-kappa B , Neoplasias Experimentais/induzido quimicamente , Proteínas de Ligação a RNA , Transdução de Sinais/genéticaRESUMO
Retinoid X receptor (RXR) regulates key cellular responses such as cell growth and development, and this regulation is frequently perturbed in various malignancies, including hepatocellular carcinoma (HCC). However, the molecule(s) that physically govern this deregulation are mostly unknown. Here, we identified RXR as an interacting partner of astrocyte-elevated gene-1 (AEG-1)/metadherin (MTDH), an oncogene upregulated in all cancers. Upon interaction, AEG-1 profoundly inhibited RXR/retinoic acid receptor (RAR)-mediated transcriptional activation. Consequently, AEG-1 markedly protected HCC and acute myelogenous leukemia (AML) cells from retinoid- and rexinoid-induced cell death. In nontumorigenic cells and primary hepatocytes, AEG-1/RXR colocalizes in the nucleus in which AEG-1 interferes with recruitment of transcriptional coactivators to RXR, preventing transcription of target genes. In tumor cells and AEG-1 transgenic hepatocytes, overexpressed AEG-1 entraps RXR in cytoplasm, precluding its nuclear translocation. In addition, ERK, activated by AEG-1, phosphorylates RXR that leads to its functional inactivation and attenuation of ligand-dependent transactivation. In nude mice models, combination of all-trans retinoic acid (ATRA) and AEG-1 knockdown synergistically inhibited growth of human HCC xenografts. The present study establishes AEG-1 as a novel homeostatic regulator of RXR and RXR/RAR that might contribute to hepatocarcinogenesis. Targeting AEG-1 could sensitize patients with HCC and AML to retinoid- and rexinoid-based therapeutics.