RESUMO
A diet deficient in donors of methyl group, such as methionine, affects DNA methylation and hepatic lipid metabolism. Methionine also affects other epigenetic mechanisms, such as microRNAs. We investigated the effects of methionine-supplemented or methionine-deficient diets on the expression of chromatin-modifying genes, global DNA methylation, the expression and methylation of genes related to lipid metabolism, and the expression of microRNAs in mouse liver. Female Swiss albino mice were fed a control diet (0.3% methionine), a methionine-supplemented diet (2% methionine), and a methionine-deficient diet (0% methionine) for 10 weeks. The genes most affected by the methionine-supplemented diet were associated with histone and DNA methyltransferases activity, while the methionine-deficient diet mostly altered the expression of histone methyltransferases genes. Both diets altered the global DNA methylation and the expression and gene-specific methylation of the lipid metabolism gene Apoa5. Both diets altered the expression of several liver homeostasis-related microRNAs, including miR-190b-5p, miR-130b-3p, miR-376c-3p, miR-411-5p, miR-29c-3p, miR-295-3p, and miR-467d-5p, with the methionine-deficient diet causing a more substantial effect. The effects of improper amounts of methionine in the diet on liver pathologies may involve a cooperative action of chromatin-modifying genes, which results in an aberrant pattern of global and gene-specific methylation, and microRNAs responsible for liver homeostasis.
Assuntos
Metionina , MicroRNAs , Animais , Cromatina/metabolismo , Metilação de DNA , Dieta , Epigênese Genética , Feminino , Fígado , Camundongos , MicroRNAs/genética , MicroRNAs/metabolismoRESUMO
Hepatocellular carcinoma (HCC) presents with a high treatment resistance and poor prognosis. Early diagnosis and preventive approaches such as chemoprevention are essential for the HCC control. Therefore, we evaluated the chemopreventive effects of butyrate-containing structured lipids (STLs) administered during the promotion stage of hepatocarcinogenesis in rats submitted to the 'resistant hepatocyte' (RH) model. Administration of butyrate-containing STLs inhibited the incidence and mean number of visible hepatic nodules per rat and reduced the number and area of glutathione S-transferase placental form-positive (GST-P+) preneoplastic focal lesions in the livers. This was accompanied by the induction of apoptosis and an increased level of hepatic butyric acid. Treatment with butyrate-containing STLs resulted in increased histone H3 lysine 9 (H3K9) acetylation, reduction of total histone deacetylase (HDAC) activity, and lower levels of HDAC4 and HDAC6 proteins. The chemopreventive effect of butyrate-containing STLs was also associated with the increased nuclear compartmentalization of p53 protein and reduced expression of the Bcl-2 protein. In addition, rats treated with butyrate-containing STLs showed decreased DNA damage and telomerase activity in the livers. These results demonstrate that the suppressive activity of butyrate-containing STLs is associated with inhibition of elevated during hepatocarcinogenesis chromatin-modifying proteins HDAC4 and HDAC6, subcellular redistribution of the p53 protein, and decreased DNA damage and telomerase activity.
Assuntos
Butiratos/metabolismo , Dano ao DNA , Glutationa S-Transferase pi/metabolismo , Desacetilase 6 de Histona/metabolismo , Histona Desacetilases/metabolismo , Lipídeos/química , Neoplasias Hepáticas Experimentais/patologia , Telomerase/metabolismo , Animais , Carcinogênese , Caspase 3/metabolismo , Neoplasias Hepáticas Experimentais/enzimologia , Neoplasias Hepáticas Experimentais/genética , Masculino , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ratos , Ratos Wistar , Frações Subcelulares/enzimologia , Proteína Supressora de Tumor p53/metabolismo , Ácido alfa-Linolênico/metabolismoRESUMO
MicroRNAs (miRNAs) are post-transcriptional gene expression regulators which expression is frequently altered in hepatocellular carcinoma (HCC). ß-ionone (ßI) is noted for its ability to inhibit persistent preneoplastic lesions (pPNLs) in liver rats. We evaluated the expression of miRNAs involved in carcinogenesis and possible targets modulated by ßI, in pPNLs and surrounding of microdissected tissues. Rats subjected to resistant hepatocyte model were treated during promotion stage with ßI (16 mg/100 g body weight) or corn oil (CO; 0.25 mL/100 g body weight; controls). Five animals receive no treatment (NT). In CO group, 38 and 29 miRNAs showed reduced expression relative to NT (P < 0.05) in pPNLs and surrounding, respectively. No miRNAs showed increased expression in surrounding of the CO compared to NT group; however, 30 miRNAs showed increased expression (P ≤ 0.05) in pPNLs of the CO group. There was no difference between ßI and CO groups (P > 0.05) in the expression of miRNAs in surrounding. In pPNLs ßI increased expression of miR-122 and miR-34a (P ≤ 0.05) and reduced of Igf2 (P ≤ 0.05), target of the latter, compared to CO. Additionally, ßI decreased the expression of miR-181c and its target Gdf2 (P ≤ 0.05). ßI reduced the expression of miR-181b and miR-708 (P ≤ 0.05) and increased the expression of their respective target mRNAs Timp3 and Mtss1 (P ≤ 0.05), relative to CO group. Modulation of miRNAs target genes by ßI was confirmed in vitro. ßI is a promising chemopreventive agent in the initial stages of hepatocarcinogenesis, as it modulates the expression of the miRNAs and target genes that can alter the metastatic phenotype of HCC. © 2016 Wiley Periodicals, Inc.
Assuntos
Anticarcinógenos/uso terapêutico , Carcinoma Hepatocelular/prevenção & controle , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Neoplasias Hepáticas/prevenção & controle , Fígado/efeitos dos fármacos , MicroRNAs/genética , Norisoprenoides/uso terapêutico , Animais , Carcinogênese/efeitos dos fármacos , Carcinogênese/metabolismo , Carcinogênese/patologia , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Humanos , Fígado/metabolismo , Fígado/patologia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Masculino , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/patologia , Lesões Pré-Cancerosas/prevenção & controle , Ratos , Ratos WistarRESUMO
Hepatocellular carcinoma (HCC), an aggressive and the fastest growing life-threatening cancer worldwide, is often diagnosed at intermediate or advanced stages of the disease, which substantially limits therapeutic approaches for its successful treatment. This indicates that the prevention of hepatocarcinogenesis is probably the most promising approach to reduce both the HCC incidence and cancer-related mortality. In previous studies, we demonstrated a potent chemopreventive effect of tributyrin, a butyric acid prodrug, on experimental hepatocarcinogenesis. The cancer-inhibitory effect of tributyrin was linked to the suppression of sustained cell proliferation and induction of apoptotic cell death driven by an activation of the p53 apoptotic signaling pathway. The goal of the present study was to investigate the underlying molecular mechanisms linked to tributyrin-mediated p53 activation. Using in vivo and in vitro models of liver cancer, we demonstrate that an increase in the level of p53 protein in nuclei, a decrease in the level of cytoplasmic p53, and, consequently, an increase in the ratio of nuclear/cytoplasmic p53 in rat preneoplastic livers and in rat and human HCC cell lines caused by tributyrin or sodium butyrate treatments was associated with a marked increase in the level of nuclear chromosome region maintenance 1 (CRM1) protein. Mechanistically, the increase in the level of nuclear p53 protein was associated with a substantially reduced binding interaction between CRM1 and p53. The results demonstrate that the cancer-inhibitory activity of sodium butyrate and its derivatives on liver carcinogenesis may be attributed to retention of p53 and CRM1 proteins in the nucleus, an event that may trigger activation of p53-mediated apoptotic cell death in neoplastic cells.
Assuntos
Carcinoma Hepatocelular/tratamento farmacológico , Compartimento Celular/efeitos dos fármacos , Carioferinas/metabolismo , Neoplasias Hepáticas/tratamento farmacológico , Receptores Citoplasmáticos e Nucleares/metabolismo , Triglicerídeos/farmacologia , Proteína Supressora de Tumor p53/metabolismo , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Ácido Butírico/farmacologia , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Citoplasma/metabolismo , Modelos Animais de Doenças , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Carioferinas/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Masculino , Ligação Proteica/efeitos dos fármacos , Ratos Wistar , Receptores Citoplasmáticos e Nucleares/genética , Proteína Supressora de Tumor p53/genética , Proteína Exportina 1RESUMO
SCOPE: Emerging evidence indicates that the use of bioactive food components is a promising strategy to prevent the development of liver cancer. The goal of this study was to examine the chemopreventive effect of butyrate-containing structured lipids (STLs) produced by an enzymatic interesterification of tributyrin and flaxseed oil on rat hepatocarcinogenesis. METHODS AND RESULTS: Male Wistar rats were subjected to a classic "resistant hepatocyte" model of liver carcinogenesis and treated with STLs, tributyrin or flaxseed oil during the initial phases of hepatocarcinogenesis. Treatment with STLs and tributyrin strongly inhibited the development of preneoplastic liver lesions. The chemopreventive activity of tributyrin was associated with the induction of apoptosis and reduction of the expression of major activated hepatocarcinogenesis-related oncogenes. Treatment with STLs caused substantially greater inhibitory effects than tributyrin on oncogene expression. CONCLUSION: These results demonstrate that the tumor-suppressing activity of butyrate-containing STLs is associated with its ability to prevent and inhibit activation of major hepatocarcinogenesis-related oncogenes. Enrichment of histone H3K9me3 and H3K27me3 at the promoter of Myc and Ccnd1 genes may be related to the inhibitory effect on oncogene expression in the livers of STL-treated rats.
Assuntos
Anticarcinógenos/farmacologia , Ácido Butírico/farmacologia , Neoplasias Hepáticas Experimentais/prevenção & controle , Animais , Anticarcinógenos/química , Ácido Butírico/química , Regulação da Expressão Gênica/efeitos dos fármacos , Histonas/genética , Histonas/metabolismo , Óleo de Semente do Linho/química , Lipídeos/química , Lipídeos/farmacologia , Neoplasias Hepáticas Experimentais/patologia , Masculino , Oncogenes , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/patologia , Lesões Pré-Cancerosas/prevenção & controle , Ratos Wistar , Triglicerídeos/química , Triglicerídeos/farmacologiaRESUMO
SCOPE: A compromised nutritional status in methyl-group donors may provoke several molecular alterations triggering the development of nonalcoholic fatty liver disease (NAFLD) in humans and experimental animals. In this study, we investigated a role and the underlying molecular mechanisms of methionine metabolic pathway malfunctions in the pathogenesis of NAFLD. METHODS AND RESULTS: We fed female Swiss albino mice a control (methionine-adequate) diet and two experimental (methionine-deficient or methionine-supplemented) diets for 10 weeks, and the levels of one-carbon metabolites, expression of one-carbon and lipid metabolism genes in the livers were evaluated. We demonstrate that both experimental diets increased hepatic levels of S-adenosyl-l-homocysteine and homocysteine, altered expression of one-carbon and lipid metabolism genes, and caused lipid accumulation, especially in mice fed the methionine-deficient diet. Markers of oxidative and ER stress response were also elevated in the livers of mice fed either diet. CONCLUSION: Our findings indicate that both dietary methionine deficiency and methionine supplementation can induce molecular abnormalities in the liver associated with the development of NAFLD, including deregulation in lipid and one-carbon metabolic pathways, and induction of oxidative and ER stress. These pathophysiological events may ultimately lead to lipid accumulation in the livers, triggering the development of NAFLD.
Assuntos
Suplementos Nutricionais , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Metionina/administração & dosagem , Metionina/deficiência , Animais , Feminino , Glutationa/sangue , Homocisteína/sangue , Fígado/metabolismo , Camundongos , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Triglicerídeos/sangueRESUMO
Dietary isoprenic derivatives such as ß-ionone (ßI) are a promising class of chemopreventive agents. In this study, cellular aspects of ßI protective activities during early hepatocarcinogenesis were evaluated. Male Wistar rats were submitted to "resistant hepatocyte" model and then received daily 16 mg/100 g body weight (b.w.) of ßI (ßI group) or only 0.25 mL/100 g b.w. of corn oil (vehicle, control group [CO]) during 4 wk, specifically during early promotion phase. Compared to controls, ßI inhibited (P < 0.05) the development of persistent preneoplastic lesions (pPNL), considered to be potential hepatocellular carcinoma (HCC) progression sites, and increased remodeling PNL (rPNL) (P < 0.05) that tend to regress to a normal phenotype. Increased ßI hepatic levels (P < 0.05), in the ßI group, were associated with its chemopreventive actions. Compared to control rats, ßI reduced the frequency of both pPNL and rPNL positive for tumor growth factor (TGF)-α (P < 0.05), reduced the frequency of pPNL stained for p65 (nuclear factor-kappaB; NF-κB) (P < 0.05), and reduced the frequency of pPNL positive for cytoplasmic p53 (P < 0.05). Our data demonstrated that ßI targets TGF-α, NF-κB, and p53 in initial phases of hepatocarcinogenesis and specifically inhibits PNL with increased probability to progress to HCC. This isoprenoid may represent a chemopreventive agent of choice for HCC control.
Assuntos
Anticarcinógenos/farmacologia , Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas Experimentais/tratamento farmacológico , Norisoprenoides/farmacologia , Animais , Quimioprevenção , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , NF-kappa B/antagonistas & inibidores , NF-kappa B/metabolismo , Ratos , Ratos Wistar , Fator de Crescimento Transformador alfa/antagonistas & inibidores , Fator de Crescimento Transformador alfa/metabolismo , Proteína Supressora de Tumor p53/antagonistas & inibidores , Proteína Supressora de Tumor p53/metabolismoRESUMO
The steady increase in the incidence and mortality of hepatocellular carcinoma (HCC) signifies a crucial need to understand better its pathogenesis to improve clinical management and prevention of the disease. The aim of this study was to investigate molecular mechanisms for the chemopreventive effects of folic acid and tributyrin alone or in combination on rat hepatocarcinogenesis. Male Wistar rats were subjected to a classic "resistant hepatocyte" model of liver carcinogenesis and treated with folic acid and tributyrin alone or in combination for 5 weeks during promotion stage. Treatment with folic acid and tributyrin alone or in combination strongly inhibited the development of glutathione-S-transferase placental form (GSTP)-positive foci. Microarray analysis showed significant changes in gene expression. A total of 498, 655 and 940 of differentially expressed genes, involved in cell cycle, p53-signaling, angiogenesis and Wnt pathways, was identified in the livers of rats treated with folic acid, tributyrin or folic acid and tributyrin. A detailed analysis of these differentially expressed genes revealed that treatments inhibited angiogenesis in the preneoplastic livers. This was evidenced by the fact that 30 out of 77 differentially expressed genes common to all three treatments are involved in the regulation of the angiogenesis pathway. The inhibition of angiogenesis was confirmed by reduced levels of CD34 protein. In conclusion, the tumor-suppressing activity of folic acid and tributyrin is associated with inhibition of angiogenesis at early stages of rat liver carcinogenesis. Importantly, the combination of folic acid and tributyrin has stronger chemopreventive effect than each of the compounds alone.
Assuntos
Carcinoma Hepatocelular/tratamento farmacológico , Ácido Fólico/administração & dosagem , Neoplasias Hepáticas/tratamento farmacológico , Triglicerídeos/administração & dosagem , Animais , Antígenos CD34/metabolismo , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Carcinogênese/induzido quimicamente , Carcinogênese/efeitos dos fármacos , Carcinogênese/patologia , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Dietilnitrosamina/toxicidade , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glutationa S-Transferase pi/metabolismo , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Masculino , Proteínas de Neoplasias/biossíntese , Neovascularização Patológica/tratamento farmacológico , Ratos , Transcriptoma/genéticaRESUMO
The reversibility of non-genotoxic phenotypic alterations has been explored in order to develop novel preventive and therapeutic approaches for cancer control. Previously, it has been demonstrated that histone deacetylase (HDAC) inhibitor tributyrin, a butyric acid prodrug, to have chemopreventive effects on rat hepatocarcinogenesis. The goal of this study was to determine molecular mechanisms associated with the chemopreventive activity of tributyrin. Male Wistar rats were allocated randomly to untreated control group and two experimental groups. Rats in the experimental group 1 were treated with maltodextrin (3g/kg body wt), and rats in experimental group 2 were treated with tributyrin (2g/kg body wt) daily for 8 weeks. Two weeks after treatment initiation, rats from experimental groups were subjected to a 'resistant hepatocyte' model of hepatocarcinogenesis. Treatment with tributyrin resulted in lower HDAC activity and Hdac3 and Hdac4 gene expression, and an increase of histone H3 lysine 9 and 18 and histone H4 lysine 16 acetylation as compared with the experimental group 1. In addition to the increase in histone acetylation, tributyrin caused an increase in the acetylation of the nuclear p53 protein. These changes were accompanied by a normalization of the p53-signaling network, particularly by the upregulation of pro-apoptotic genes, and a consequent increase of apoptosis and autophagy in the livers of tributyrin-treated rats. These results indicate that the chemopreventive activity of tributyrin may be related to an increase of histone and p53 acetylation, which could lead to the induction of the p53 apoptotic pathway.