RESUMEN
Gastric cancer is the second leading cause of cancer-related death worldwide. Herein, we investigated the role of transcription factor Yin Yang 1 (YY1), a multi-functional protein, in tumorigenesis of gastric cancer cells. Results showed that YY1 contributed to gastric carcinogenesis of SC-M1 cells including growth, viability, and abilities of colony formation, migration, invasion, and tumorsphere formation. Levels of pluripotency genes CD44, Oct4, SOX-2, and Nanog were also up-regulated by YY1 in SC-M1 cells. Additionally, the 3'-untranslated region (3'-UTR) of YY1 mRNA was the target of microRNA-34 (miR-34) family consisting of miR-34a, miR-34b, and miR-34c. Overexpression of miR-34 family suppressed carcinogenesis through down-regulation of YY1 in NUGC-3 gastric cancer cells scarcely expressing miR-34 family. Alternatively, knockdown of miR-34 family promoted tumorigenesis via up-regulation of YY1 in SC-M1 and AZ521 gastric cancer cells with higher levels of miR-34 family. The miR-34 family also affected tumorsphere ultra-structure and inhibited the xenografted tumor growth as well as lung metastasis of SC-M1 cells through YY1. Expressions of miR-34a and miR-34c in gastric cancer tissues of patients were lower than those in normal tissues. Taken together, these results suggest that miR-34 family-YY1 axis plays an important role in the control of gastric carcinogenesis.
Asunto(s)
Regulación Neoplásica de la Expresión Génica , MicroARNs/genética , Neoplasias Gástricas/genética , Factor de Transcripción YY1/genética , Regiones no Traducidas 3'/genética , Animales , Western Blotting , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular , Supervivencia Celular/genética , Humanos , Ratones Endogámicos BALB C , Ratones Desnudos , Interferencia de ARN , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Neoplasias Gástricas/metabolismo , Carga Tumoral/genética , Ensayos Antitumor por Modelo de Xenoinjerto/métodos , Factor de Transcripción YY1/metabolismoRESUMEN
The Notch signal pathway plays multifaceted roles to promote or suppress tumorigenesis. The Notch1 receptor intracellular domain (N1IC), the activated form of the Notch1 receptor, activates the c-myc proto-oncogene. The complex of N1IC and transcription factor YY1 binds to the human c-myc promoter to enhance c-myc expression in a CBF1-independent manner. Here we demonstrated that N1IC interacted with the c-Myc-regulating proteins alpha-enolase and c-myc promoter binding protein 1 (MBP-1). Both alpha-enolase and MBP-1 suppressed the N1IC-enhanced activity of the c-myc promoter in a CBF1-independent manner. The YY1 response element in front of the P2 c-myc promoter was essential and sufficient for the modulation of c-myc by N1IC and alpha-enolase or MBP-1. Furthermore, N1IC, YY1, and alpha-enolase or MBP-1 but not CBF1 bound to the c-myc promoter through associating with the YY1 response element. Hemin-induced erythroid differentiation was suppressed by N1IC in K562 cells. This suppression was relieved by the expression of alpha-enolase and MBP-1. In addition, both alpha-enolase and MBP-1 suppressed the N1IC-enhanced colony-forming ability through c-myc. These results indicate that the activated Notch1 receptor and alpha-enolase or MBP-1 cooperate in controlling c-myc expression through binding the YY1 response element of the c-myc promoter to regulate tumorigenesis.
Asunto(s)
Biomarcadores de Tumor/metabolismo , Proteínas de Unión al ADN/metabolismo , Fosfopiruvato Hidratasa/metabolismo , Proteínas Proto-Oncogénicas c-myc/metabolismo , Receptor Notch1/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Diferenciación Celular , Línea Celular Tumoral , Núcleo Celular/metabolismo , Ensayo de Unidades Formadoras de Colonias , Células Eritroides/citología , Regulación Neoplásica de la Expresión Génica , Humanos , Proteína de Unión a la Señal Recombinante J de las Inmunoglobulinas/metabolismo , Unión Proteica , Estructura Terciaria de Proteína , Proto-Oncogenes Mas , Proteínas Proto-Oncogénicas c-myc/genética , Receptor Notch1/química , Elementos de Respuesta/genética , Activación Transcripcional/genética , Factor de Transcripción YY1/genética , Factor de Transcripción YY1/metabolismoRESUMEN
Transcription factor Ying Yang 1 (YY1) indirectly regulates the C promoter-binding factor 1 (CBF1)-dependent Notch1 signaling via direct interaction with the Notch1 receptor intracellular domain (N1IC) on CBF1-response elements. To evaluate the possibility that the N1IC might modulate the gene expression of YY1 target genes through associating with YY1 on the YY1-response elements, we herein investigated the effect of Notch1 signaling on the expression of YY1 target genes. We found that the N1IC bound to the double-stranded oligonucleotides of YY1-response element to activate luciferase activity of the reporter gene with YY1-response elements through a CBF1-independent manner. Furthermore, the N1IC also bound to the promoter of human c-myc oncogene, a YY1 target gene, to elevate c-myc expression via a CBF1-independent pathway. The activation of reporter genes with YY1-response elements or human c-myc promoter by N1IC depended on the formation of N1IC-YY1-associated complex. To delineate the role of the Notch signal pathway in tumorigenesis, K562 cell lines expressing the N1IC were established. Compared with control cells, the proliferation and the tumor growth of N1IC-expressing K562 cells were suppressed. Taken together, these results suggest that the N1IC enhances the human c-myc promoter activity that is partially modulated by YY1 through a CBF1-independent pathway. However, the enhancement of c-myc expression by N1IC is insufficient to promote the tumor growth of K562 cells.
Asunto(s)
Regulación de la Expresión Génica , Genes myc , Proteína de Unión a la Señal Recombinante J de las Inmunoglobulinas/genética , Receptor Notch1/fisiología , Factor de Transcripción YY1/metabolismo , Animales , Secuencia de Bases , Células COS , Proteínas de Unión al Calcio/genética , Chlorocebus aethiops , Cromatina/genética , Cromatina/fisiología , Cartilla de ADN , Haplorrinos , Humanos , Proteína de Unión a la Señal Recombinante J de las Inmunoglobulinas/deficiencia , Péptidos y Proteínas de Señalización Intercelular/genética , Células K562 , Proteínas de la Membrana/genética , Ratones , Ratones Desnudos , Plásmidos , Reacción en Cadena de la Polimerasa , Proteínas Serrate-Jagged , Transducción de Señal , TransfecciónRESUMEN
Notch receptors are evolutionarily conserved from Drosophila to human and play important roles in cell fate decisions. After ligand binding, Notch receptors are cleaved to release their intracellular domains. The intracellular domains, the activated form of Notch receptors, are then translocated into the nucleus where they interact with other transcriptional machinery to regulate the expression of cellular genes. To dissect the molecular mechanisms of Notch signaling, the cellular targets that interact with Notch1 receptor intracellular domain (N1IC) were screened. In this study, we found that endogenous transcription factor Ying Yang 1 (YY1) was associated with exogenous N1IC in human K562 erythroleukemic cells. The ankyrin (ANK) domain of N1IC and zinc finger domains of YY1 were essential for the association of N1IC and YY1 according to the pull-down assay of glutathione S-transferase fusion proteins. Furthermore, both YY1 and N1IC were present in a large complex of the nucleus to suppress the luciferase reporter activity transactivated by Notch signaling. The transcription factor YY1 indirectly regulated the transcriptional activity of the wild-type CBF1-response elements via the direct interaction of N1IC and CBF1. We also demonstrated the association between endogenous N1IC and intrinsic YY1 in human acute T-cell lymphoblastic leukemia cell lines. Taken together, these results indicate that transcription factor YY1 may modulate Notch signaling via association with the high molecular weight Notch complex.