RESUMO
Peritoneum is the most common site for ovarian cancer metastasis. Here we investigate how cancer epigenetics regulates reciprocal tumor-stromal interactions in peritoneal metastasis of ovarian cancer. Firstly, we find that omental stromal fibroblasts enhance colony formation of metastatic ovarian cancer cells, and de novo expression of transforming growth factor-alpha (TGF-α) is induced in stromal fibroblasts co-cultured with ovarian cancer cells. We also observed an over-expression of tumor necrosis factor-alpha (TNF-α) in ovarian cancer cells, which is regulated by promoter DNA hypomethylation as well as chromatin remodeling. Interestingly, this ovarian cancer-derived TNF-α induces TGF-α transcription in stromal fibroblasts through nuclear factor-κB (NF-κB). We further show that TGF-α secreted by stromal fibroblasts in turn promotes peritoneal metastasis of ovarian cancer through epidermal growth factor receptor (EGFR) signaling. Finally, we identify a TNFα-TGFα-EGFR interacting loop between tumor and stromal compartments of human omental metastases. Our results therefore demonstrate cancer epigenetics induces a loop of cancer-stroma-cancer interaction in omental microenvironment that promotes peritoneal metastasis of ovarian cancer cells via TNFα-TGFα-EGFR.
Assuntos
Receptores ErbB/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias Ovarianas/metabolismo , Neoplasias Peritoneais/metabolismo , Fator de Crescimento Transformador alfa/metabolismo , Microambiente Tumoral , Fator de Necrose Tumoral alfa/metabolismo , Adulto , Idoso , Animais , Comunicação Celular , Linhagem Celular Tumoral , Feminino , Fibroblastos/metabolismo , Fibroblastos/patologia , Humanos , Camundongos , Camundongos Nus , Pessoa de Meia-Idade , Metástase Neoplásica , Transplante de Neoplasias , Neoplasias Ovarianas/patologia , Neoplasias Peritoneais/patologia , Neoplasias Peritoneais/secundário , Células Estromais/metabolismo , Células Estromais/patologiaRESUMO
Aberrant expression and altered function of transcription factors (TFs) have vital roles in many aspects of tumor development and progression. In this study, we investigated the functional significance of a TF, Yin Yang1 (YY1) in tumorigenesis of endometrioid endometrial carcinoma (EEC). We demonstrated that YY1 is upregulated in EEC cell lines and primary tumors; and its expression is associated with tumor stages. Depletion of YY1 inhibits EEC cell proliferation and migration both in vitro and in vivo, whereas overexpression of YY1 promotes EEC cell growth. These results suggest that YY1 functions as an oncogenic factor in EEC. Transcriptome analysis revealed a significant effect of YY1 on critical aspects of EEC tumorigenesis through inhibition of APC expression. Further mechanistic investigation uncovered a new epigenetic silencing mode of APC by YY1 through recruitment of EZH2 and trimethylation of histone 3 lysine 27 on its promoter region. Moreover, YY1 overexpression was found to be a consequence of miR-193a-5p downregulation through direct miR-193a-5p-YY1 interplay. Our results therefore establish a novel miR-193a-5p-YY1-APC axis, which contributes to EEC development, and may serve as future intervention target.
Assuntos
Proteína da Polipose Adenomatosa do Colo/genética , Carcinoma Endometrioide/genética , Neoplasias do Endométrio/genética , Regulação Neoplásica da Expressão Gênica/fisiologia , MicroRNAs/genética , Fator de Transcrição YY1/genética , Proteína da Polipose Adenomatosa do Colo/metabolismo , Animais , Carcinoma Endometrioide/metabolismo , Carcinoma Endometrioide/patologia , Neoplasias do Endométrio/metabolismo , Neoplasias do Endométrio/patologia , Feminino , Inativação Gênica , Humanos , Immunoblotting , Imuno-Histoquímica , Histona Desmetilases com o Domínio Jumonji/metabolismo , Camundongos , Camundongos Nus , MicroRNAs/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais/fisiologia , Ensaios Antitumorais Modelo de Xenoenxerto , Fator de Transcrição YY1/metabolismoRESUMO
MicroRNAs (miRNAs) regulate mRNA stability and protein expression, and certain miRNAs have been demonstrated to act either as oncogenes or tumor suppressors. Differential miRNA expression signatures have been documented in many human cancers but the role of miRNAs in endometrioid endometrial cancer (EEC) remains poorly understood. This study identifies significantly dysregulated miRNAs of EEC cells, and characterizes their impact on the malignant phenotype. We studied the expression of 365 human miRNAs using Taqman low density arrays in EECs and normal endometriums. Candidate differentially expressed miRNAs were validated by quantitative real-time PCR. Expression of highly dysregulated miRNAs was examined in vitro through the effect of anti-/pre-miRNA transfection on the malignant phenotype. We identified 16 significantly dysregulated miRNAs in EEC and 7 of these are novel findings with respect to EEC. Antagonizing the function of miR-7, miR-194 and miR-449b, or overexpressing miR-204, repressed migration, invasion and extracellular matrix-adhesion in HEC1A endometrial cancer cells. FOXC1 was determined as a target gene of miR-204, and two binding sites in the 3'-untranslated region were validated by dual luciferase reporter assay. FOXC1 expression was inversely related to miR-204 expression in EEC. Functional analysis revealed the involvement of FOXC1 in migration and invasion of HEC1A cells. Our results present dysfunctional miRNAs in endometrial cancer and identify a crucial role for miR-204-FOXC1 interaction in endometrial cancer progression. This miRNA signature offers a potential biomarker for predicting EEC outcomes, and targeting of these cancer progression- and metastasis-related miRNAs offers a novel potential therapeutic strategy for the disease.
