RESUMO
Nucleus accumbens-associated protein-1 (NAC1), a nuclear factor of the BTB/POZ gene family, has emerging roles in cancer. In this study, we identified the NAC1-HDAC4-HIF-1α axis as an important pathway in regulating glycolysis and hypoxic adaptation in tumor cells. We show that nuclear NAC1 binds to histone deacetylase type 4 (HDAC4), hindering phosphorylation of HDAC4 at Ser246 and preventing its nuclear export that leads to cytoplasmic degradation of the deacetylase. Accumulation of HDAC4 in the nuclei results in an attenuation of HIF-1α acetylation, enhancing the stabilization and transcriptional activity of HIF-1α and strengthening adaptive response of cells to hypoxia. We also show the role of NAC1 in promoting glycolysis in a mouse xenograft model, and demonstrate that knockdown of NAC1 expression can reinforce the antitumor efficacy of bevacizumab, an inhibitor of angiogenesis. Clinical implication of the NAC1-HDAC4-HIF-1α pathway is suggested by the results showing that expression levels of these proteins are significantly correlative in human tumor specimens and associated with the disease progression. This study not only reveals an important function of NAC1 in regulating glycolysis, but also identifies the NAC1-HDAC4-HIF-1α axis as a novel molecular pathway that promotes survival of hypoxic tumor cells.
Assuntos
Histona Desacetilases/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Núcleo Accumbens/metabolismo , Proteínas Repressoras/metabolismo , Neoplasias do Colo do Útero/metabolismo , Animais , Hipóxia Celular/fisiologia , Linhagem Celular Tumoral , Sobrevivência Celular , Progressão da Doença , Feminino , Glicólise , Células HeLa , Histona Desacetilases/genética , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Camundongos , Proteínas Repressoras/genética , Transfecção , Microambiente Tumoral , Neoplasias do Colo do Útero/genética , Neoplasias do Colo do Útero/patologiaRESUMO
miR-30d has been observed to be significantly down-regulated in human anaplastic thyroid carcinoma (ATC), and is believed to be an important event in thyroid cell transformation. In this study, we found that miR-30d has a critical role in modulating sensitivity of ATC cells to cisplatin, a commonly used chemotherapeutic drug for treatment of this neoplasm. Using a mimic of miR-30d, we demonstrated that miR-30d could negatively regulate the expression of beclin 1, a key autophagy gene, leading to suppression of the cisplatin-activated autophagic response that protects ATC cells from apoptosis. A reporter gene assay demonstrated that the binding sequences of miR-30d in the beclin 1-3' UTR was the region required for the inhibition of beclin 1 expression by this miRNA. We further showed that inhibition of the beclin 1-mediated autophagy by the miR-30d mimic sensitized ATC cells to cisplatin both in vitro (cell culture) and in vivo (animal xenograft model). These results suggest that dysregulation of miR-30d in ATC cells is responsible for the insensitivity to cisplatin by promoting autophagic survival. Thus, miR-30d may be exploited as a potential target for therapeutic intervention in the treatment of ATC.
Assuntos
Antineoplásicos/farmacologia , Proteínas Reguladoras de Apoptose/antagonistas & inibidores , Proteínas Reguladoras de Apoptose/genética , Autofagia/genética , Cisplatino/farmacologia , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/genética , MicroRNAs/genética , Neoplasias da Glândula Tireoide/genética , Regiões 3' não Traduzidas/efeitos dos fármacos , Regiões 3' não Traduzidas/fisiologia , Animais , Antineoplásicos/uso terapêutico , Proteínas Reguladoras de Apoptose/biossíntese , Autofagia/efeitos dos fármacos , Proteína Beclina-1 , Linhagem Celular Tumoral , Cisplatino/uso terapêutico , Humanos , Proteínas de Membrana/biossíntese , Camundongos , Camundongos Endogâmicos BALB C , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/fisiologia , Carcinoma Anaplásico da Tireoide , Neoplasias da Glândula Tireoide/tratamento farmacológico , Ensaios Antitumorais Modelo de Xenoenxerto/métodosRESUMO
Programmed cell death 1 (PD-1) has recently been reported to have a genetic association in several autoimmune diseases. The object of this study was to investigate the association of PD-1 polymorphisms with aplastic anemia (AA) in the Chinese Han population. In a case-control association study, three single-nucleotide polymorphisms (SNP), PD-1.3 G/A, PD-1.5 C/T, and PD-1.9 T/C, were genotyped in 166 AA patients and 264 healthy controls using polymerase chain reaction-restriction fragment length polymorphism assay. All genotype distributions in the patients and the controls were in Hardy-Weinberg equilibrium. The associations of genotypes and alleles with AA were analyzed. No differences in genotype and allele frequencies were elucidated for SNPs in intron 4 and exon 5. In conclusion, we show no association of selected SNPs in PDCD1 gene with AA in the Chinese Han population.
Assuntos
Anemia Aplástica/genética , Povo Asiático/genética , Polimorfismo de Nucleotídeo Único , Receptor de Morte Celular Programada 1/genética , Adolescente , Adulto , Anemia Aplástica/etnologia , Estudos de Casos e Controles , Distribuição de Qui-Quadrado , China/epidemiologia , Éxons , Feminino , Frequência do Gene , Predisposição Genética para Doença , Humanos , Íntrons , Masculino , Pessoa de Meia-Idade , Razão de Chances , Fenótipo , Reação em Cadeia da Polimerase , Medição de Risco , Fatores de Risco , Adulto JovemRESUMO
The effects and mechanisms of action of beta-aescin and 5-fluorouracil (5-FU), alone and in combination, were studied in human hepatocellular carcinoma SMMC-7721 cells. Growth inhibition, cell cycle distribution, apoptosis, Bcl-2 expression and caspase activity were assessed. The Isobole-method/interaction-index analysis was applied to evaluate the synergy, additivity or antagonism of these agents. The results indicate that mixtures of beta-aescin and 5-FU showed a synergistic effect on the 50% inhibitory effect when their ratio was 4:1 when compared with either agent alone. The mechanism of action could be through the synergistic arrest of the cell cycle, induction of apoptosis, activation of caspases-3, 8 and 9, and down-regulation Bcl-2 expression. The results suggest that mixtures of these two agents had a synergistic inhibitory effect on SMMC-7721 cells, an observation which might be useful for the further development of anti-cancer drugs.
