RESUMO
Histone methylation is involved in various biological and pathological processes including cancer development. In this study, we found that EED, a component of Polycomb repressive complex-2 (PRC2) that catalyzes methylation of lysine 27 of histone H3 (H3K27), was involved in epithelial-mesenchymal transition (EMT) of cancer cells induced by Transforming Growth Factor-beta (TGF-ß). The expression of EED was increased during TGF-ß-induced EMT and knockdown of EED inhibited TGF-ß-induced morphological conversion of the cells associated with EMT. EED knockdown antagonized TGF-ß-dependent expression changes of EMT-related genes such as CDH1, ZEB1, ZEB2 and microRNA-200 (miR-200) family. Chromatin immunoprecipitation assays showed that EED was implicated in TGF-ß-induced transcriptional repression of CDH1 and miR-200 family genes through the regulation of histone H3 methylation and EZH2 occupancies on their regulatory regions. Our study demonstrated a novel role of EED, which regulates PRC2 activity and histone methylation during TGF-ß-induced EMT of cancer cells.
Assuntos
Transição Epitelial-Mesenquimal/fisiologia , Neoplasias/patologia , Neoplasias/fisiopatologia , Complexo Repressor Polycomb 2/fisiologia , Fator de Crescimento Transformador beta/fisiologia , Antígenos CD , Caderinas/genética , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal/genética , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Células HT29 , Histonas/metabolismo , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , MicroRNAs/genética , Neoplasias/genética , Complexo Repressor Polycomb 2/antagonistas & inibidores , Complexo Repressor Polycomb 2/genética , Regiões Promotoras Genéticas , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Homeobox 2 de Ligação a E-box com Dedos de Zinco , Homeobox 1 de Ligação a E-box em Dedo de ZincoRESUMO
DOT1L is a histone H3 lysine 79 (H3K79) methyltransferase mainly implicated in leukemia. Here we analyzed the function of DOT1L in breast cancer cells. The expression of DOT1L was up-regulated in malignant breast cancer tissues. Over-expression of DOT1L significantly increased the sphere formation and the cell migration activities of MCF7 breast cancer cell line. In contrast, knockdown of DOT1L reduced the cell migration activity of MDA-MB-231 breast cancer cell line. BCAT1, which encodes a branched-chain amino acid transaminase, was identified as one of the target genes controlled by DOT1L through the regulation of H3K79 methylation. Mechanistic investigation revealed that BCAT1 might be an important regulator responsible for DOT1L-mediated sphere formation and cell migration in breast cancer cells.
Assuntos
Neoplasias da Mama/patologia , Metiltransferases/metabolismo , Metástase Neoplásica , Transaminases/genética , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Feminino , Regulação da Expressão Gênica , Histona-Lisina N-Metiltransferase , Humanos , MetilaçãoRESUMO
Histone methylation plays a crucial role in various biological and pathological processes including cancer development. In this study, we discovered that JARID2, an interacting component of Polycomb repressive complex-2 (PRC2) that catalyzes methylation of lysine 27 of histone H3 (H3K27), was involved in Transforming Growth Factor-beta (TGF-ß)-induced epithelial-mesenchymal transition (EMT) of A549 lung cancer cell line and HT29 colon cancer cell line. The expression of JARID2 was increased during TGF-ß-induced EMT of these cell lines and knockdown of JARID2 inhibited TGF-ß-induced morphological conversion of the cells associated with EMT. JARID2 knockdown itself had no effect in the expression of EMT-related genes but antagonized TGF-ß-dependent expression changes of EMT-related genes such as CDH1, ZEB family and microRNA-200 family. Chromatin immunoprecipitation assays showed that JARID2 was implicated in TGF-ß-induced transcriptional repression of CDH1 and microRNA-200 family genes through the regulation of histone H3 methylation and EZH2 occupancies on their regulatory regions. Our study demonstrated a novel role of JARID2 protein, which may control PRC2 recruitment and histone methylation during TGF-ß-induced EMT of lung and colon cancer cell lines.
Assuntos
Neoplasias do Colo/metabolismo , Transição Epitelial-Mesenquimal , Neoplasias Pulmonares/metabolismo , Complexo Repressor Polycomb 2/metabolismo , Antígenos CD , Caderinas/genética , Caderinas/metabolismo , Proteína Potenciadora do Homólogo 2 de Zeste , Células HT29 , Histonas/metabolismo , Humanos , MicroRNAs/genética , Complexo Repressor Polycomb 2/genética , Fator de Crescimento Transformador beta/farmacologiaRESUMO
Histone methylation is implicated in various biological and pathological processes including cancer development. In this study, we discovered that ectopic expression of KDM5B, a histone H3 lysine 4 (H3K4) demethylase, promoted epithelial-mesenchymal transition (EMT) of cancer cells. KDM5B increased the expression of transcription factors, ZEB1 and ZEB2, followed by downregulation of E-cadherin and upregulation of mesenchymal marker genes. The expression of the microRNA-200 (miR-200) family, which specifically targets ZEB1 and ZEB2, was reduced in the cells with KDM5B overexpression. We found that KDM5B repressed the expression of the miR-200 family by changing histone H3 methylation status of their regulatory regions. The introduction of miR-200 precursor in the cells inhibited EMT induction by KDM5B, suggesting that miR-200 family was a critical downstream mediator of KDM5B-promoted EMT. Furthermore, knockdown of KDM5B was shown to affect the expression of EMT-related genes, indicating the involvement of endogenous KDM5B. Our study demonstrated a novel role of KDM5B histone lysine demethylase in EMT, which may contribute to malignant progression of cancer.