RESUMO
Intestinal metaplasia in gastric mucosa is considered a preneoplastic lesion that progresses to gastric cancer. However, the molecular networks underlying this lesion formation are largely unknown. NKX6.3 is known to be an important regulator in gastric mucosal epithelial differentiation. In this study, we characterized the effects of NKX6.3 that may contribute to gastric intestinal metaplasia. NKX6.3 expression was significantly reduced in gastric mucosae with intestinal metaplasia. The mRNA expression levels of both NKX6.3 and CDX2 predicted the intestinal metaplasia risk, with an area under the receiver operating characteristic curve value of 0.9414 and 0.9971, respectively. Notably, the NKX6.3 expression level was positively and inversely correlated with SOX2 and CDX2, respectively. In stable AGS(NKX6.3) and MKN1(NKX6.3) cells, NKX6.3 regulated the expression of CDX2 and SOX2 by directly binding to the promoter regions of both genes. Nuclear NKX6.3 expression was detected only in gastric epithelial cells without intestinal metaplasia. Furthermore, NKX6.3-induced TWSG1 bound to BMP4 and inhibited BMP4-binding activity to BMPR-II. These data suggest that NKX6.3 might function as a master regulator of gastric differentiation by affecting SOX2 and CDX2 expression and the NKX6.3 inactivation may result in intestinal metaplasia in gastric epithelial cells.
Assuntos
Transdiferenciação Celular , Transformação Celular Neoplásica/genética , Inativação Gênica , Proteínas de Homeodomínio/genética , Lesões Pré-Cancerosas/genética , Fatores de Transcrição SOXB1/genética , Neoplasias Gástricas/genética , Fatores de Transcrição/genética , Animais , Antígenos de Bactérias/genética , Antígenos de Bactérias/metabolismo , Área Sob a Curva , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Proteína Morfogenética Óssea 4/genética , Proteína Morfogenética Óssea 4/metabolismo , Fator de Transcrição CDX2 , Linhagem Celular Tumoral , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Modelos Animais de Doenças , Feminino , Mucosa Gástrica/metabolismo , Mucosa Gástrica/microbiologia , Mucosa Gástrica/patologia , Regulação Neoplásica da Expressão Gênica , Predisposição Genética para Doença , Infecções por Helicobacter/genética , Infecções por Helicobacter/metabolismo , Infecções por Helicobacter/patologia , Helicobacter pylori/genética , Helicobacter pylori/metabolismo , Proteínas de Homeodomínio/metabolismo , Humanos , Metaplasia , Camundongos Endogâmicos C57BL , Fenótipo , Lesões Pré-Cancerosas/metabolismo , Lesões Pré-Cancerosas/microbiologia , Lesões Pré-Cancerosas/patologia , Regiões Promotoras Genéticas , Proteínas/genética , Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Curva ROC , Medição de Risco , Fatores de Risco , Fatores de Transcrição SOXB1/metabolismo , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/microbiologia , Neoplasias Gástricas/patologia , Fatores de Transcrição/metabolismo , TransfecçãoRESUMO
Histone deacetylase 2 (HDAC2) is aberrantly regulated and plays a pivotal role in the development of hepatocellular carcinoma (HCC) through regulation of cell-cycle components at the transcriptional level, but the underlying mechanism leading to oncogenic HDAC2 remains unknown. In this study, we show that expression of CK2α (casein kinase II α subunit) was up-regulated in a large cohort of human HCC patients, and that high expression of CK2α was significantly associated with poor prognosis of HCC patients in terms of five-year overall survival. It was also found that CK2α over-expression positively correlated with HDAC2 over-expression in a subset of HCCs. We observed that treatment with epidermal growth factor (EGF) elicited an increase in CK2α expression and Akt phosphorylation, causing induction of HDAC2 expression in liver cancer cells. It was also observed that ectopic expression of dominant-negative CK2α blocked EGF-induced HDAC2 expression, and that ectopic CK2α expression attenuated the suppressive effect of Akt knockdown on HDAC2 expression in liver cancer cells. Targeted disruption of CK2α influenced the cell cycle, causing a significant increase in the number of liver cancer cells remaining in G2/M phase, and suppressed growth via repression of Cdc25c and cyclin B in liver cancer cells. Taken together, our findings suggest the oncogenic potential of CK2α in liver tumorigenesis. Furthermore, a regulatory mechanism for HDAC2 expression is proposed whereby EGF induces transcriptional activation of HDAC2 by CK2α/Akt activation in liver cancer cells. Therefore, this makes CK2α a promising target in cancer therapy.
Assuntos
Carcinogênese , Fator de Crescimento Epidérmico/metabolismo , Receptores ErbB/agonistas , Regulação Neoplásica da Expressão Gênica , Histona Desacetilase 2/metabolismo , Neoplasias Hepáticas/metabolismo , Carcinoma Hepatocelular/metabolismo , Caseína Quinase II/antagonistas & inibidores , Caseína Quinase II/genética , Caseína Quinase II/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Estudos de Coortes , Receptores ErbB/metabolismo , Histona Desacetilase 2/genética , Humanos , Fígado/metabolismo , Proteínas Mutantes/antagonistas & inibidores , Proteínas Mutantes/metabolismo , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Fosforilação , Processamento de Proteína Pós-Traducional , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Interferência de RNA , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Transdução de Sinais , Análise de SobrevidaRESUMO
Several lines of evidence indicate that, together with deregulated growth, alteration of apoptosis plays a pivotal role in tumorigenesis. PUMA, a pro-apoptotic member of Bcl-2 family, mediates p53-dependent and -independent apoptosis. BAD is also a pro-apoptotic Bcl-2 family member and phosphorylation of BAD protein inhibits the pro-apoptosis function of BAD. To see whether the alteration of protein expressions of PUMA and phospho-BAD (p-BAD) are characteristics of human colorectal cancers, we analyzed the expression of these proteins in 103 colorectal carcinomas by immunohistochemistry. Also, we analyzed the mutation of the Bcl-2 homology 3 (BH3) domain of PUMA gene, an important domain in the apoptosis function of PUMA, by single-strand conformation polymorphism (SSCP) in 98 colorectal carcinomas. p-BAD immunostaining was detected in 62 cases (60.1%) of the 103 carcinomas, whereas it was not detected in the normal colonic mucosal epithelial cells. PUMA protein expression was detected in both cancer cells and normal mucosal cells in all of the 103 cases. However, the cancer cells showed higher intensities of PUMA immunostaining than the normal cells of the same patients in 50.4% of the cases. There was no association of the p-BAD expression with the PUMA expression. The mutational analysis revealed no PUMA BH3 domain mutation in the cancers. Our data indicated that expressions of both PUMA and p-BAD were increased in the colorectal cancer cells, and suggested that the increased expression of these proteins in malignant colorectal epithelial cells compared to the normal mucosal epithelial cells may possibly alter the cell death regulation during colorectal tumorigenesis.
