RESUMO
Studies have demonstrated that microRNA 185 may be a promising therapeutic target in liver cancer. However, its role in hepatocellular carcinoma is largely unknown. In this study, the proliferation of human HepG2 cells was inhibited by transfection of microRNA 185 mimics. Cell-cycle analysis revealed arrest at the G0/G1 phase. Transfection of HepG2 cells with microRNA 185 mimics significantly induced apoptosis. These data confirmed microRNA 185 as a potent cancer suppressor. We demonstrated that microRNA 185 was a compelling inducer of autophagy, for the first time. When cell autophagy was inhibited by chloroquine or 3-methyladenine, microRNA 185 induced more cell apoptosis. MicroRNA 185 acted as a cancer suppressor by regulating AKT1 expression and phosphorylation. Dual-luciferase reporter assays indicated that microRNA 185 suppressed the expression of target genes including RHEB, RICTOR, and AKT1 by directly interacting with their 3'-untranslated regions. Binding site mutations eliminated microRNA 185 responsiveness. Our findings demonstrate a new role of microRNA 185 as a key regulator of hepatocellular carcinoma via autophagy by dysregulation of AKT1 pathway.
Assuntos
Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , MicroRNAs/genética , Proteínas Proto-Oncogênicas c-akt/genética , Autofagia/genética , Materiais Biomiméticos/administração & dosagem , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/terapia , Ciclo Celular/genética , Processos de Crescimento Celular/genética , Terapia Genética/métodos , Células Hep G2 , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/terapia , MicroRNAs/administração & dosagem , MicroRNAs/biossíntese , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Transfecção/métodosRESUMO
Although human echovirus 25 (E-25), a type of the enterovirus B species, is implicated in aseptic meningitis, information on its gene structure, evolution, and virulence are limited. We report here the complete genome sequence of a novel recombinant E-25 strain (E25/2010/CHN/BJ) isolated from a neonate with hand, foot, and mouth disease complicated by encephalitis in Beijing, China in 2010. The complete viral genome consists of 7429 nucleotides (nts), including a 6585-nt open reading frame. Phylogenetic dendrogram based on VP1 gene regions revealed that this strain belonged to subgroup D4, which contains the other E-25 strains isolated from China in recent years. The difference in the amino acid sites (P130S, K/T135I) of the VP1 region may affect its immunogenicity. SimPlot and Bootscan analyses suggested that E25/2010/CHN/BJ is a recombination result of E-25 and Coxsackievirus B3 (CVB-3) strains. Our results would facilitate the study of the origin, evolution, and molecular epidemiology of E-25.
Assuntos
Encefalite Viral/virologia , Enterovirus Humano B/genética , Genoma Viral , Doença de Mão, Pé e Boca/virologia , RNA Viral/genética , Recombinação Genética , Análise de Sequência de DNA , Pequim , Análise por Conglomerados , Enterovirus Humano B/classificação , Enterovirus Humano B/isolamento & purificação , Doença de Mão, Pé e Boca/complicações , Humanos , Dados de Sequência Molecular , Fases de Leitura Aberta , Filogenia , Homologia de SequênciaRESUMO
NS5ATP9, a gene up-regulated by NS5A, plays a crucial oncogenic role in several types of human tumours. However, the underlying mechanisms remain unclear. Autophagy, an evolutionarily conserved catabolic process, maintains cellular homeostasis under stress conditions, such as starvation, and plays a crucial role in tumour initiation and progression. Here, we report that NS5ATP9 mRNA and protein expression was up-regulated in starved HepG2 cells and that the up-regulated NS5ATP9 played a functional role in starvation-induced autophagy. Overexpression or silencing of this gene showed contrasting effects on Beclin 1 and on starvation-induced autophagy. Furthermore, NS5ATP9-mediated autophagy is required for promotion of tumour cell growth, and this effect could be inhibited with 3-methyladenine, chloroquine or by Beclin 1-silencing. Thus, the mechanism for NS5ATP9-promoted autophagy is Beclin 1-dependent in the condition of starvation, and for hepatoblastoma cell growth is also Beclin 1-dependent.
