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1.
Cancer Lett ; 587: 216724, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38373689

RESUMO

CD24 is a well-characterized breast cancer (BC) stem cell (BCSC) marker. Primary breast tumor cells having CD24-negativity together with CD44-positivity is known to maintain high metastatic potential. However, the functional role of CD24 gene in triple-negative BC (TNBC), an aggressive subtype of BC, is not well understood. While the significance of CD24 in regulating immune pathways is well recognized in previous studies, the significance of CD24 low expression in onco-signaling and metabolic rewiring is largely unknown. Using CD24 knock-down and over-expression TNBC models, our in vitro and in vivo analysis suggest that CD24 is a tumor suppressor in metastatic TNBC. Comprehensive in silico gene expression analysis of breast tumors followed by lipidomic and metabolomic analyses of CD24-modulated cells revealed that CD24 negativity induces mitochondrial oxidative phosphorylation and reprograms TNBC metabolism toward the fatty acid beta-oxidation (FAO) pathway. CD24 silencing activates PPARα-mediated regulation of FAO in TNBC cells. Further analysis using reverse-phase protein array and its validation using CD24-modulated TNBC cells and xenograft models nominated CD24-NF-κB-CPT1A signaling pathway as the central regulatory mechanism of CD24-mediated FAO activity. Overall, our study proposes a novel role of CD24 in metabolic reprogramming that can open new avenues for the treatment strategies for patients with metastatic TNBC.


Assuntos
NF-kappa B , Neoplasias de Mama Triplo Negativas , Humanos , Neoplasias de Mama Triplo Negativas/patologia , PPAR alfa/genética , Linhagem Celular Tumoral , Ácidos Graxos/metabolismo , Antígeno CD24/genética , Antígeno CD24/metabolismo
2.
Commun Biol ; 5(1): 493, 2022 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-35610507

RESUMO

The major limitations of DNA-targeting chemotherapy drugs include life-threatening toxicity, acquired resistance and occurrence of secondary cancers. Here, we report a small molecule, Carbazole Blue (CB), that binds to DNA and inhibits cancer growth and metastasis by targeting DNA-related processes that tumor cells use but not the normal cells. We show that CB inhibits the expression of pro-tumorigenic genes that promote unchecked replication and aberrant DNA repair that cancer cells get addicted to survive. In contrast to chemotherapy drugs, systemic delivery of CB suppressed breast cancer growth and metastasis with no toxicity in pre-clinical mouse models. Using PDX and ex vivo explants from estrogen receptor (ER) positive, ER mutant and TNBC patients, we further demonstrated that CB effectively blocks therapy-sensitive and therapy-resistant breast cancer growth without affecting normal breast tissue. Our data provide a strong rationale to develop CB as a viable therapeutic for treating breast cancers.


Assuntos
Neoplasias da Mama , Animais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , DNA , Reparo do DNA , Feminino , Humanos , Camundongos , Receptores de Estrogênio/metabolismo
3.
Br J Cancer ; 124(12): 1902-1911, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33859341

RESUMO

Cancer cells have the plasticity to adjust their metabolic phenotypes for survival and metastasis. A developmental programme known as epithelial-to-mesenchymal transition (EMT) plays a critical role during metastasis, promoting the loss of polarity and cell-cell adhesion and the acquisition of motile, stem-cell characteristics. Cells undergoing EMT or the reverse mesenchymal-to-epithelial transition (MET) are often associated with metabolic changes, as the change in phenotype often correlates with a different balance of proliferation versus energy-intensive migration. Extensive crosstalk occurs between metabolism and EMT, but how this crosstalk leads to coordinated physiological changes is still uncertain. The elusive connection between metabolism and EMT compromises the efficacy of metabolic therapies targeting metastasis. In this review, we aim to clarify the causation between metabolism and EMT on the basis of experimental studies, and propose integrated theoretical-experimental efforts to better understand the coupled decision-making of metabolism and EMT.


Assuntos
Metabolismo Energético/fisiologia , Transição Epitelial-Mesenquimal/fisiologia , Neoplasias/patologia , Animais , Diferenciação Celular , Transição Epitelial-Mesenquimal/genética , Humanos , Metástase Neoplásica , Neoplasias/metabolismo , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/fisiologia
4.
Cancers (Basel) ; 11(10)2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31575084

RESUMO

Yes-associated protein (YAP)-1 is highly upregulated in pancreatic cancer and associated with tumor progression. However, little is known about the role of YAP1 and related genes in pancreatic cancer. Here, we identified target genes regulated by YAP1 and explored their role in pancreatic cancer progression and the related clinical implications. Analysis of different pancreatic cancer databases showed that Neuromedin U (NMU) expression was positively correlated with YAP1 expression in the tumor group. The Cancer Genome Atlas data indicated that high YAP1 and NMU expression levels were associated with poor mean and overall survival. YAP1 overexpression induced NMU expression and transcription and promoted cell motility in vitro and tumor metastasis in vivo via upregulation of epithelial-mesenchymal transition (EMT), whereas specific inhibition of NMU in cells stably expressing YAP1 had the opposite effect in vitro and in vivo. To define this functional association, we identified a transcriptional enhanced associate domain (TEAD) binding site in the NMU promoter and demonstrated that YAP1-TEAD binding upstream of the NMU gene regulated its transcription. These results indicate that the identified positive correlation between YAP1 and NMU is a potential novel drug target and biomarker in metastatic pancreatic cancer.

5.
Proc Natl Acad Sci U S A ; 116(9): 3909-3918, 2019 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-30733294

RESUMO

Metabolic plasticity enables cancer cells to switch their metabolism phenotypes between glycolysis and oxidative phosphorylation (OXPHOS) during tumorigenesis and metastasis. However, it is still largely unknown how cancer cells orchestrate gene regulation to balance their glycolysis and OXPHOS activities. Previously, by modeling the gene regulation of cancer metabolism we have reported that cancer cells can acquire a stable hybrid metabolic state in which both glycolysis and OXPHOS can be used. Here, to comprehensively characterize cancer metabolic activity, we establish a theoretical framework by coupling gene regulation with metabolic pathways. Our modeling results demonstrate a direct association between the activities of AMPK and HIF-1, master regulators of OXPHOS and glycolysis, respectively, with the activities of three major metabolic pathways: glucose oxidation, glycolysis, and fatty acid oxidation. Our model further characterizes the hybrid metabolic state and a metabolically inactive state where cells have low activity of both glycolysis and OXPHOS. We verify the model prediction using metabolomics and transcriptomics data from paired tumor and adjacent benign tissue samples from a cohort of breast cancer patients and RNA-sequencing data from The Cancer Genome Atlas. We further validate the model prediction by in vitro studies of aggressive triple-negative breast cancer (TNBC) cells. The experimental results confirm that TNBC cells can maintain a hybrid metabolic phenotype and targeting both glycolysis and OXPHOS is necessary to eliminate their metabolic plasticity. In summary, our work serves as a platform to symmetrically study how tuning gene activity modulates metabolic pathway activity, and vice versa.


Assuntos
Proteínas Quinases Ativadas por AMP/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Redes e Vias Metabólicas/genética , Neoplasias de Mama Triplo Negativas/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Linhagem Celular Tumoral , Ácidos Graxos/metabolismo , Feminino , Glucose/metabolismo , Glicólise/genética , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Mitocôndrias/metabolismo , Modelos Teóricos , Fosforilação Oxidativa , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologia
6.
Cells ; 7(3)2018 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-29534029

RESUMO

Aerobic glycolysis, also referred to as the Warburg effect, has been regarded as the dominant metabolic phenotype in cancer cells for a long time. More recently, it has been shown that mitochondria in most tumors are not defective in their ability to carry out oxidative phosphorylation (OXPHOS). Instead, in highly aggressive cancer cells, mitochondrial energy pathways are reprogrammed to meet the challenges of high energy demand, better utilization of available fuels and macromolecular synthesis for rapid cell division and migration. Mitochondrial energy reprogramming is also involved in the regulation of oncogenic pathways via mitochondria-to-nucleus retrograde signaling and post-translational modification of oncoproteins. In addition, neoplastic mitochondria can engage in crosstalk with the tumor microenvironment. For example, signals from cancer-associated fibroblasts can drive tumor mitochondria to utilize OXPHOS, a process known as the reverse Warburg effect. Emerging evidence shows that cancer cells can acquire a hybrid glycolysis/OXPHOS phenotype in which both glycolysis and OXPHOS can be utilized for energy production and biomass synthesis. The hybrid glycolysis/OXPHOS phenotype facilitates metabolic plasticity of cancer cells and may be specifically associated with metastasis and therapy-resistance. Moreover, cancer cells can switch their metabolism phenotypes in response to external stimuli for better survival. Taking into account the metabolic heterogeneity and plasticity of cancer cells, therapies targeting cancer metabolic dependency in principle can be made more effective.

7.
Asian-Australas J Anim Sci ; 31(3): 457-466, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29268577

RESUMO

OBJECTIVE: The present study aimed to assess the nitrogen (N) use efficiency of acidified pig slurry for regrowth yield and its environmental impacts on perennial ryegrass swards. METHODS: The pH of digested pig slurry was adjusted to 5.0 or 7.0 by the addition of sulfuric acid and untreated as a control. The pig slurry urea of each treatment was labeled with 15N urea and applied at a rate of 200 kg N/ha immediately after cutting. Soil and herbage samples were collected at 7, 14, and 56 d of regrowth. The flux of pig slurry-N to regrowth yield and soil N mineralization were analyzed, and N losses via NH3, N2O emission and NO3- leaching were also estimated. RESULTS: The pH level of the applied slurry did not have a significant effect on herbage yield or N content of herbage at the end of regrowth, whereas the amount of N derived from pig slurry urea (NdfSU) was higher in both herbage and soils in pH-controlled plots. The NH4+-N content and the amount of N derived from slurry urea into soil NH4+ fraction (NdfSU-NH4+) was significantly higher in in the pH 5 plot, whereas NO3- and NdfSU-NO3- were lower than in control plots over the entire regrowth period. Nitrification of NH4+-N was delayed in soil amended with acidified slurry. Compared to non-pH-controlled pig slurry (i.e. control plots), application of acidified slurry reduced NH3 emissions by 78.1%, N2O emissions by 78.9% and NO3- leaching by 17.81% over the course of the experiment. CONCLUSION: Our results suggest that pig slurry acidification may represent an effective means of minimizing hazardous environmental impacts without depressing regrowth yield.

8.
Clin Cancer Res ; 23(18): 5537-5546, 2017 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-28533225

RESUMO

Purpose: The incidence of hepatocellular carcinoma is increasing in the United States, and liver cancer is the second leading cause of cancer-related mortality worldwide. Nonalcoholic steatohepatitis (NASH) is becoming an important risk for hepatocellular carcinoma, and most patients with hepatocellular carcinoma have underlying liver cirrhosis and compromised liver function, which limit treatment options. Thus, novel therapeutic strategies to prevent or treat hepatocellular carcinoma in the context of NASH and cirrhosis are urgently needed.Experimental Design: Constitutive activation of STAT3 is frequently detected in hepatocellular carcinoma tumors. STAT3 signaling plays a pivotal role in hepatocellular carcinoma survival, growth, angiogenesis, and metastasis. We identified C188-9, a novel small-molecule STAT3 inhibitor using computer-aided rational drug design. In this study, we evaluated the therapeutic potential of C188-9 for hepatocellular carcinoma treatment and prevention.Results: C188-9 showed antitumor activity in vitro in three hepatocellular carcinoma cell lines. In mice with hepatocyte-specific deletion of Pten (HepPten- mice), C188-9 treatment blocked hepatocellular carcinoma tumor growth, reduced tumor development, and reduced liver steatosis, inflammation, and bile ductular reactions, resulting in improvement of the pathological lesions of NASH. Remarkably, C188-9 also greatly reduced liver injury in these mice as measured by serum aspartate aminotransferase and alanine transaminase levels. Analysis of gene expression showed that C188-9 treatment of HepPten- mice resulted in inhibition of signaling pathways downstream of STAT3, STAT1, TREM-1, and Toll-like receptors. In contrast, C188-9 treatment increased liver specification and differentiation gene pathways.Conclusions: Our results suggest that C188-9 should be evaluated further for the treatment and/or prevention of hepatocellular carcinoma. Clin Cancer Res; 23(18); 5537-46. ©2017 AACR.


Assuntos
Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/metabolismo , Naftóis/farmacologia , Hepatopatia Gordurosa não Alcoólica/metabolismo , Fator de Transcrição STAT3/antagonistas & inibidores , Sulfonamidas/farmacologia , Animais , Antineoplásicos/farmacologia , Biópsia , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/tratamento farmacológico , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Citocinas/metabolismo , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Humanos , Imuno-Histoquímica , Mediadores da Inflamação , Testes de Função Hepática , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/patologia , Imageamento por Ressonância Magnética , Camundongos , Camundongos Knockout , Hepatopatia Gordurosa não Alcoólica/diagnóstico , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
9.
Stem Cells ; 34(5): 1284-96, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26731713

RESUMO

MicroRNA expression profiling in human liver progenitor cells following hepatocytic differentiation identified miR-122 and miR-194 as the microRNAs most strongly upregulated during hepatocytic differentiation of progenitor cells. MiR-194 was also highly upregulated following hepatocytic differentiation of human embryonic stem cells (hESCs). Overexpression of miR-194 in progenitor cells accelerated their differentiation into hepatocytes, as measured by morphological features such as canaliculi and expression of hepatocytic markers. Overexpression of miR-194 in hESCs induced their spontaneous differentiation, a phenotype accompanied with accelerated loss of the pluripotent factors OCT4 and NANOG and decrease in mesoderm marker HAND1 expression. We then identified YAP1 as a direct target of miR-194. Inhibition of YAP1 strongly induced hepatocytic differentiation of progenitor cells and YAP1 overexpression reversed the miR-194-induced hepatocytic differentiation of progenitor cells. In conclusion, we identified miR-194 as a potent inducer of hepatocytic differentiation of progenitor cells and further identified YAP1 as a mediator of miR-194's effects on hepatocytic differentiation and liver progenitor cell fate. Stem Cells 2016;34:1284-1296.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Diferenciação Celular/genética , Hepatócitos/citologia , Hepatócitos/metabolismo , MicroRNAs/metabolismo , Fosfoproteínas/metabolismo , Sequência de Bases , Linhagem Celular , Células-Tronco Embrionárias Humanas/citologia , Células-Tronco Embrionárias Humanas/metabolismo , Humanos , Fígado/citologia , MicroRNAs/genética , Fatores de Transcrição , Regulação para Cima/genética , Proteínas de Sinalização YAP
10.
Hepatology ; 63(3): 864-79, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26599259

RESUMO

UNLABELLED: The death rate from hepatocellular carcinoma (HCC) is increasing, and liver cancer is the second leading cause of cancer-related mortality worldwide. Most patients with HCC have underlying liver cirrhosis and compromised liver function, limiting treatment options. Cirrhosis is associated with cell dedifferentiation and expansion of hepatocholangiolar progenitor cells. We identified a microRNA signature associated with HCC and hepatocytic differentiation of progenitor cells. We further identified miR-148a as an inducer of hepatocytic differentiation that is down-regulated in HCC. MiR-148a-mimetic treatment in vivo suppressed tumor growth, reduced tumor malignancy and liver fibrosis, and prevented tumor development. These effects were associated with an increased differentiated phenotype and mediated by IκB kinase alpha/NUMB/NOTCH signaling. CONCLUSION: miR-148a is an inhibitor of the IκB kinase alpha/NUMB/NOTCH pathway and an inducer of hepatocytic differentiation that when deregulated promotes HCC initiation and progression. Differentiation-targeted therapy may be a promising strategy to treat and prevent HCC.


Assuntos
Carcinoma Hepatocelular/terapia , Diferenciação Celular , Neoplasias Hepáticas/terapia , MicroRNAs/metabolismo , Animais , Benzazepinas , Biomarcadores/metabolismo , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Fibrose , Hepatócitos/citologia , Hepatócitos/metabolismo , Humanos , Quinase I-kappa B/metabolismo , Fígado/patologia , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fenótipo , Receptores Notch/antagonistas & inibidores , Receptores Notch/metabolismo
11.
J Hepatol ; 63(2): 408-19, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25817558

RESUMO

BACKGROUND & AIMS: Most common reason behind changes in histone deacetylase (HDAC) function is its overexpression in cancer. However, among HDACs in liver cancer, HDAC6 is uniquely endowed with a tumor suppressor, but the mechanism underlying HDAC6 inactivation has yet to be uncovered. METHODS: Microarray profiling and target prediction programs were used to identify miRNAs targeting HDAC6. A series of inhibitors, activators and siRNAs was introduced to validate regulatory mechanisms for microRNA-221-3p (miR-221) governing HDAC6 in hepatocarcinogenesis. RESULTS: Comprehensive miRNA profiling analysis identified seven putative endogenous miRNAs that are significantly upregulated in hepatocellular carcinoma (HCC). While miR-221 was identified as a suppressor of HDAC6 by ectopic expression of miRNA mimics in Dicer knockdown cells, targeted-disruption of miR-221 repressed cancer cell growth through derepressing HDAC6 expression. Suppression of HDAC6 via miR-221 was induced by JNK/c-Jun signaling in liver cancer cells but not in normal hepatic cells. Additionally, cytokine-induced NF-κBp65 independently regulated miR-221, thereby suppressing HDAC6 expression in HCC cells. HCC tissues derived from chemical-induced rat and H-ras12V transgenic mice liver cancer models validated that JNK/c-Jun activation and NF-κBp65 nuclear translocation are essential for the transcription of miR-221 leading to repression of HDAC6 in HCC. CONCLUSIONS: Our findings suggest that the functional loss or suppression of the tumor suppressor HDAC6 is caused by induction of miR-221 through coordinated JNK/c-Jun- and NF-κB-signaling pathways during liver tumorigenesis, providing a novel target for the molecular treatment of liver malignancies.


Assuntos
Regulação Neoplásica da Expressão Gênica , Histona Desacetilases/genética , Neoplasias Hepáticas Experimentais/genética , MicroRNAs/genética , RNA Neoplásico/genética , Animais , Progressão da Doença , Desacetilase 6 de Histona , Histona Desacetilases/biossíntese , Neoplasias Hepáticas Experimentais/metabolismo , Neoplasias Hepáticas Experimentais/patologia , Camundongos , Camundongos Transgênicos , MicroRNAs/biossíntese , Reação em Cadeia da Polimerase , Ratos
12.
Cancer Res ; 75(9): 1859-67, 2015 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25769721

RESUMO

miR-21 is upregulated in hepatocellular carcinoma and intrahepatic cholangiocarcinoma, where it is associated with poor prognosis. Here, we offer preclinical evidence that miR-21 offers a therapeutic and chemopreventive target in these liver cancers. In mice with hepatic deletion of Pten, anti-miR-21 treatment reduced liver tumor growth and prevented tumor development. These effects were accompanied with a decrease in liver fibrosis and a concomitant reduction of CD24(+) liver progenitor cells and S100A4(+) cancer-associated stromal cells. Notch2 inhibition also occurred in tumors following anti-miR-21 treatment. We further showed that miR-21 is necessary for the survival of CD24(+) progenitor cells, a cellular phenotype mediated by Notch2, osteopontin, and integrin αv. Our results identify miR-21 as a key regulator of tumor-initiating cell survival, malignant development, and growth in liver cancer, highlighting the role of CD24(+) cells in the expansion of S100A4(+) cancer-associated stromal cells and associated liver fibrosis.


Assuntos
Antígeno CD24/biossíntese , Cirrose Hepática/genética , Cirrose Hepática/terapia , Neoplasias Hepáticas Experimentais/prevenção & controle , MicroRNAs/antagonistas & inibidores , Células-Tronco Neoplásicas/patologia , Animais , Apoptose/genética , Antígeno CD24/genética , Carcinogênese/genética , Sobrevivência Celular/genética , Integrina alfaV/genética , Cirrose Hepática/patologia , Neoplasias Hepáticas Experimentais/genética , Neoplasias Hepáticas Experimentais/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , MicroRNAs/genética , Células-Tronco Neoplásicas/metabolismo , Osteopontina/genética , PTEN Fosfo-Hidrolase/genética , Receptor Notch2/genética
13.
Cancer Lett ; 335(2): 455-62, 2013 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-23499894

RESUMO

Aberrant regulation of histone deacetylase 2 (HDAC2) plays a pivotal role in the development of hepatocellular carcinoma (HCC), but, the underlying mechanism leading to HDAC2 overexpression is not well understood. We performed microRNA (miRNA) profiling analysis in a subset of HCCs, and identified four down-regulated miRNAs that may target HDAC2 in HCC. Ectopic expression of miRNA mimics evidenced that miR-145 suppresses HDAC2 expression in HCC cells. This treatment repressed cancer cell growth and recapitulated HDAC2 knockdown effects on HCC cells. In conclusion, we suggest that loss or suppression of miR-145 may cause aberrant overexpression of HDAC2 and promote HCC tumorigenesis.


Assuntos
Carcinoma Hepatocelular/genética , Genes Supressores de Tumor , Histona Desacetilase 2/genética , Neoplasias Hepáticas/genética , MicroRNAs/metabolismo , Animais , Linhagem Celular Tumoral , Proliferação de Células , Histona Desacetilase 2/metabolismo , Humanos , Camundongos , Camundongos Nus , MicroRNAs/genética , Transplante de Neoplasias , Interferência de RNA , RNA Interferente Pequeno , Ensaios Antitumorais Modelo de Xenoenxerto
14.
Mol Cancer Res ; 11(1): 62-73, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23175521

RESUMO

Aberrant regulation of histone deacetylase 2 (HDAC2) was reported for gastric cancers. However, responsive cancer genes in disease onset and progression are less understood. HDAC2 expression was studied by quantitative RT-PCR and Western blotting. The functional consequences of HDAC2 knockdown on cell-cycle regulation, programmed cell death, and gene target identification was investigated by flow cytometry, Western blotting, electron microscopy, anchorage-independent colony formation, and cell migration assay and by whole-genome microarray. Therapeutic efficacy of HDAC2 knockdown was determined in nude mice with small hairpin expressing human gastric cancer cells. Epigenetic regulation of p16(INK4a) was studied by methylation-specific PCR and chromatin-IP to evidence HDAC2 or acetylated-histone-H4 binding at gene specific promoter sequences. HDAC2 gene and protein expression was significantly upregulated in different histopathologic grades of human gastric cancers and cancer cell lines. HDAC2 inactivation significantly reduced cell motility, cell invasion, clonal expansion, and tumor growth. HDAC2 knockdown-induced G(1)-S cell cycle arrest and restored activity of p16(INK4a) and the proapoptotic factors. This treatment caused PARP cleavage and hypophosphorylation of the Rb-protein, repressed cyclinD1, CDK4, and Bcl-2 expression and induced autophagic phenotype, that is, LC3B-II conversion. Some gastric tumors and cancer cells displayed p16(INK4a) promoter hypermethylation but treatment with 5-aza-deoxycitidine restored activity. With others the methylation status was unchanged. Here, chromatin-IP evidenced HDAC2 binding. Nonetheless, expression of p16(INK4a) was restored by HDAC2 knockdown with notable histone-H4-acetylation, as determined by chromatin-IP. Thus, p16(INK4a) is regulated by HDAC2. HDAC2 is a bona fide target for novel molecular therapies in gastric cancers.


Assuntos
Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Regulação Neoplásica da Expressão Gênica , Histona Desacetilase 2/metabolismo , Neoplasias Gástricas/genética , Animais , Apoptose/fisiologia , Linhagem Celular Tumoral , Inibidor p16 de Quinase Dependente de Ciclina/genética , Epigênese Genética/genética , Histona Desacetilase 2/genética , Humanos , Camundongos , Camundongos Nus , Células NIH 3T3 , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Neoplasias Gástricas/enzimologia , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Transfecção
15.
Toxicol Lett ; 216(1): 1-8, 2013 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-23147375

RESUMO

Predictions of toxicity are central for the assessment of chemical toxicity, and the effects of environmental toxic compounds are still a major issue for predicting potential human health risks. Among the various environmental toxicants, polycyclic aromatic hydrocarbons (PAHs) are an important class of environmental pollutant, and many PAHs are known or suspected carcinogens. In the present study, to investigate whether characteristic expression profiles of PAHs exist in rat liver and whether a characteristic molecular signature can discriminate and predict among different PAHs at an early exposure time, we analyzed the genome-wide expression profiles of rat livers exposed to PAHs [benzo[a]anthracene (BA), benzo[a]pyrene (BP), phenanthrene (PA) and naphthalene (NT)]. At early time-point PAH exposure, large-scale gene expression analysis resulted in characteristic molecular signatures for each PAH, and supervised analysis identified 1183 outlier genes as a distinct molecular signature discerning PAHs from the normal control group. We identified 158 outlier genes as early predictive and surrogate markers for predicting each tested PAH by combination of two different multi-classification algorithms with 100% accuracy through a leave-one out cross-validation method. In conclusion, the characteristic gene expression signatures from a rat model system could be used as predictable and discernible gene-based biomarkers for the detection and prediction of PAHs, and these molecular markers may provide insights into the underlying mechanisms for genotoxicity of exposure to PAHs from environmental aspect.


Assuntos
Poluentes Ambientais/toxicidade , Fígado/química , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Animais , Biomarcadores , Análise por Conglomerados , Poluentes Ambientais/química , Poluentes Ambientais/isolamento & purificação , Expressão Gênica , Perfilação da Expressão Gênica , Dose Letal Mediana , Fígado/efeitos dos fármacos , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Receptores Ativados por Proliferador de Peroxissomo/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/química , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley
16.
Hepatology ; 57(3): 1055-67, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23079745

RESUMO

UNLABELLED: Sirtuins are nicotinamide adenine dinucleotide oxidized form (NAD(+) )-dependent deacetylases and function in cellular metabolism, stress resistance, and aging. For sirtuin7 (SIRT7), a role in ribosomal gene transcription is proposed, but its function in cancer has been unclear. In this study we show that SIRT7 expression was up-regulated in a large cohort of human hepatocellular carcinoma (HCC) patients. SIRT7 knockdown influenced the cell cycle and caused a significant increase of liver cancer cells to remain in the G1 /S phase and to suppress growth. This treatment restored p21(WAF1/Cip1) , induced Beclin-1, and repressed cyclin D1. In addition, sustained suppression of SIRT7 reduced the in vivo tumor growth rate in a mouse xenograft model. To explore mechanisms in SIRT7 regulation, microRNA (miRNA) profiling was carried out. This identified five significantly down-regulated miRNAs in HCC. Bioinformatics analysis of target sites and ectopic expression in HCC cells showed that miR-125a-5p and miR-125b suppressed SIRT7 and cyclin D1 expression and induced p21(WAF1/Cip1) -dependent G1 cell cycle arrest. Furthermore, treatment of HCC cells with 5-aza-2'-deoxycytidine or ectopic expression of wildtype but not mutated p53 restored miR-125a-5p and miR-125b expression and inhibited tumor cell growth, suggesting their regulation by promoter methylation and p53 activity. To show the clinical significance of these findings, mutations in the DNA binding domain of p53 and promoter methylation of miR-125b were investigated. Four out of nine patients with induced SIRT7 carried mutations in the p53 gene and one patient showed hypermethylation of the miR-125b promoter region. CONCLUSION: Our findings suggest the oncogenic potential of SIRT7 in hepatocarcinogenesis. A regulatory loop is proposed whereby SIRT7 inhibits transcriptional activation of p21(WAF1/Cip1) by way of repression of miR-125a-5p and miR-125b. This makes SIRT7 a promising target in cancer therapy. (HEPATOLOGY 2013).


Assuntos
Carcinoma Hepatocelular/genética , Regulação Neoplásica da Expressão Gênica/genética , Neoplasias Hepáticas/genética , MicroRNAs/genética , Sirtuínas/genética , Animais , Carcinoma Hepatocelular/metabolismo , Linhagem Celular Tumoral , Técnicas de Silenciamento de Genes , Terapia Genética/métodos , Genômica , Humanos , Neoplasias Hepáticas/metabolismo , Camundongos , Camundongos Nus , RNA Mensageiro/metabolismo , Sirtuínas/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
17.
Environ Sci Technol ; 46(23): 12882-9, 2012 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-23153324

RESUMO

Persistent organic pollutants (POPs) are degradation-resistant anthropogenic chemicals that accumulate in the food chain and in adipose tissue, and are among the most hazardous compounds ever synthesized. However, their toxic mechanisms are still undefined. To investigate whether characteristic molecular signatures can discriminate individual POP and provide prediction markers for the early detection of POPs exposure in an animal model, we performed transcriptomic analysis of rat liver tissues after exposure to POPs. The six different POPs (toxaphene, hexachlorobenzene, chlordane, mirex, dieldrin, and heptachlor) were administered to 11-week-old male Sprague-Dawley rats, and after 48 h of exposure, RNAs were extracted from liver tissues and subjected to rat whole genome expression microarrays. Early during exposure, conventional toxicological analysis including changes in the body and organ weight, histopathological examination, and blood biochemical analysis did not reflect any toxicant stresses. However, unsupervised gene expression analysis of rat liver tissues revealed in a characteristic molecular signature for each toxicant, and supervised analysis identified 2708 outlier genes that discerned the POPs exposure group from the vehicle-treated control. Combination analysis of two different multiclassifications suggested 384 genes as early detection markers for predicting each POP exposure with 100% accuracy. The data from large-scale gene expression analysis of a different POP exposure in rat model suggest that characteristic expression profiles exist in liver hepatic cells and multiclassification of POP-specific molecular signatures can discriminate each toxicant at an early exposure time. The use of these molecular markers may be more widely implemented in combination with more traditional techniques for assessment and prediction of toxicity exposure to POPs from an environmental aspect.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas/diagnóstico , Poluentes Ambientais/toxicidade , Fígado/efeitos dos fármacos , Praguicidas/toxicidade , Transcriptoma/efeitos dos fármacos , Animais , Doença Hepática Induzida por Substâncias e Drogas/genética , Doença Hepática Induzida por Substâncias e Drogas/patologia , Dieldrin/toxicidade , Fungicidas Industriais/toxicidade , Heptacloro/toxicidade , Hexaclorobenzeno/toxicidade , Inseticidas/toxicidade , Fígado/metabolismo , Fígado/patologia , Masculino , Mirex/toxicidade , Ratos , Ratos Sprague-Dawley , Toxafeno/toxicidade , Testes de Toxicidade/métodos
18.
Oncol Lett ; 4(5): 873-877, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23162614

RESUMO

The putative tumor suppressor, DBC1 (deleted in breast cancer-1), was recently found to negatively regulate SIRT1 in vitro and in vivo, but the mechanism whereby DBC1 regulates SIRT1 in liver cancer remains to be elucidated. In this study, it was found that although the expression of DBC1 and SIRT1 was not aberrantly regulated in a large cohort of human hepatocellular carcinoma (HCC) patients, these proteins were highly overexpressed in a subset of HCC tissues compared with surrounding non-cancer tissues. In liver cancer, DBC1 and SIRT1 were found to be positively correlated. Inactivation of DBC1 or SIRT1 reduced SNU-182 (a liver cancer cell line) proliferation as determined by MTT viability assays. Notably, although DBC1 functions as a negative regulator of SIRT1 in A549 lung cancer cells since it suppresses the deacetylase activity of the p53 protein, it did not affect the p53 deacetylase activity of SIRT1 in SNU-182 cells. Taken together, we conclude that DBC1 is associated with SIRT1 in HCC, but that it does not inhibit SIRT1.

19.
PLoS One ; 7(4): e34265, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22496786

RESUMO

Histone deacetylases (HDACs) are known to play a central role in the regulation of several cellular properties interlinked with the development and progression of cancer. Recently, HDAC1 has been reported to be overexpressed in hepatocellular carcinoma (HCC), but its biological roles in hepatocarcinogenesis remain to be elucidated. In this study, we demonstrated overexpression of HDAC1 in a subset of human HCCs and liver cancer cell lines. HDAC1 inactivation resulted in regression of tumor cell growth and activation of caspase-independent autophagic cell death, via LC3B-II activation pathway in Hep3B cells. In cell cycle regulation, HDAC1 inactivation selectively induced both p21(WAF1/Cip1) and p27(Kip1) expressions, and simultaneously suppressed the expression of cyclin D1 and CDK2. Consequently, HDAC1 inactivation led to the hypophosphorylation of pRb in G1/S transition, and thereby inactivated E2F/DP1 transcription activity. In addition, we demonstrated that HDAC1 suppresses p21(WAF1/Cip1) transcriptional activity through Sp1-binding sites in the p21(WAF1/Cip1) promoter. Furthermore, sustained suppression of HDAC1 attenuated in vitro colony formation and in vivo tumor growth in a mouse xenograft model. Taken together, we suggest the aberrant regulation of HDAC1 in HCC and its epigenetic regulation of gene transcription of autophagy and cell cycle components. Overexpression of HDAC1 may play a pivotal role through the systemic regulation of mitotic effectors in the development of HCC, providing a particularly relevant potential target in cancer therapy.


Assuntos
Autofagia , Carcinoma Hepatocelular/patologia , Caspases/metabolismo , Histona Desacetilase 1/antagonistas & inibidores , Neoplasias Hepáticas/patologia , Mitose/fisiologia , Apoptose , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Ciclo Celular , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Células Cultivadas , Imunoprecipitação da Cromatina , Ensaio de Unidades Formadoras de Colônias , Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Inibidor de Quinase Dependente de Ciclina p27/genética , Inibidor de Quinase Dependente de Ciclina p27/metabolismo , Citometria de Fluxo , Imunofluorescência , Histona Desacetilase 1/genética , Histona Desacetilase 1/metabolismo , Humanos , Fígado/citologia , Fígado/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Luciferases/metabolismo , Regiões Promotoras Genéticas , RNA Interferente Pequeno/genética , Reação em Cadeia da Polimerase em Tempo Real , Proteína do Retinoblastoma , Fator de Transcrição Sp1 , Ativação Transcricional
20.
J Cell Biochem ; 113(6): 2167-77, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22492270

RESUMO

Histone deacetylase 2 (HDAC2) is crucial for embryonic development, affects cytokine signaling relevant for immune responses, and is often significantly overexpressed in solid tumors, but little is known of its role in human lung cancer. In this study, we demonstrated the aberrant expression of HDAC2 in lung cancer tissues and investigated oncogenic properties of HDAC2 in human lung cancer cell lines. HDAC2 inactivation resulted in regression of tumor cell growth and activation of cellular apoptosis via p53 and Bax activation and Bcl2 suppression. In cell cycle regulation, HDAC2 inactivation caused induction of p21WAF1/CIP1 expression, and simultaneously suppressed the expressions of cyclin E2, cyclin D1, and CDK2, respectively. Consequently, this led to the hypophosphorylation of pRb protein in G1/S transition and thereby inactivated E2F/DP1 target gene transcriptions of A549 cells. In addition, we demonstrated that HDAC2 directly regulated p21WAF1/CIP1 expression in a p53-independent manner. However, HDAC1 was not related to p21WAF1/CIP1 expression and tumorigenesis of lung cancer. Lastly, we observed that sustained-suppression of HDAC2 in A549 lung cancer cells attenuated in vitro tumorigenic properties and in vivo tumor growth of the mouse xenograft model. Taken together, we suggest that the aberrant regulation of HDAC2 and its epigenetic regulation of gene transcription in apoptosis and cell cycle components play an important role in the development of lung cancer.


Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Apoptose , Proteínas de Ciclo Celular/metabolismo , Histona Desacetilase 2/metabolismo , Neoplasias Pulmonares/metabolismo , Animais , Apoptose/genética , Proteínas Reguladoras de Apoptose/genética , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Ciclina D1/metabolismo , Quinase 2 Dependente de Ciclina/metabolismo , Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Ciclinas/metabolismo , Fatores de Transcrição E2F/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Pulmonares/patologia , Camundongos , Camundongos Nus , Fosforilação , Interferência de RNA , RNA Interferente Pequeno , Proteína do Retinoblastoma/metabolismo , Transcrição Gênica , Transplante Heterólogo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Proteína X Associada a bcl-2/metabolismo , Proteína de Morte Celular Associada a bcl/metabolismo
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