Persistent colonization of the gastric mucosa by Helicobacter pylori (Hp) elicits chronic inflammation and aberrant epithelial cell proliferation, which increases the risk of gastric cancer. We examined the ability of microRNAs to modulate gastric cell proliferation in response to persistent Hp infection and found that epigenetic silencing of miR-210 plays a key role in gastric disease progression. Importantly, DNA methylation of the miR-210 gene was increased in Hp-positive human gastric biopsies as compared to Hp-negative controls. Moreover silencing of miR-210 in gastric epithelial cells promoted proliferation. We identified STMN1 and DIMT1 as miR-210 target genes and demonstrated that inhibition of miR-210 expression augmented cell proliferation by activating STMN1 and DIMT1. Together, our results highlight inflammation-induced epigenetic silencing of miR-210 as a mechanism of induction of chronic gastric diseases, including cancer, during Hp infection.
Epigenetic silencing of miR-210 increases the proliferation of gastric epithelium during chronic Helicobacter pylori infection.
Cell line
View SamplesCells located at the invasive front and in the tumor mass of mouse cervical squamous cell carcinomas were isolated by laser microdissection from hematoxylin-stained HPV/E2 sections. 7 months old HPV/E2 mice treated with oestrogen develop invasive cervical squamous cell carcinomas. This model recapitulates human invasive cervical neoplasias.
Inflammatory Cytokines Induce Podoplanin Expression at the Tumor Invasive Front.
Specimen part
View SamplesOsteosarcoma (OS) is the malignant bone tumor with a high tendency to metastasize to the lung, where the molecular mechanisms are unclear. The mouse OS cell line LM8 has been isolated originally from the Dunn OS cell line by in vivo selection as a subline with a high metastatic potential to the lung.
Stable knockdown of S100A4 suppresses cell migration and metastasis of osteosarcoma.
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Classification of Epstein-Barr virus-positive gastric cancers by definition of DNA methylation epigenotypes.
Specimen part, Cell line
View SamplesAberrant promoter methylation is known to be deeply involved in human gastric carcinogenesis, while association of Epstein-Barr virus (EBV) to the aberrant methylation has not been fully clarified. We analyzed promoter methylation in clinical gastric cancer cases using illumina's Infinium beadarray, and hierarchical clustering analysis classified gastric cancer into three subgroups: low and high methylation epigenotypes in EBV-negative cases, and markedly higher methylation epigenotype that was completely matched to EBV-positive cases. Three epigenotypes were characterized by three groups of genes: genes methylated specifically in the EBV-positive epigenotype (EBV(+)-markers, e.g. CXXC4, TIMP2, PLXND1), genes methylated both in EBV-positive and high epigenotypes (High-markers, e.g. COL9A2, EYA1, ZNF365), and genes methylated all in EBV-positive, high and low epigenotypes of gastric cancer (Common-markers, e.g. AMPH, SORCS3, AJAP1). Polycomb repressive complex (PRC)-target genes in ES cells were significantly enriched in High- and Common-markers (P=2x10-15 and 2x10-34, respectively), but not in EBV(+)-markers (P=0.2), suggesting a different cause for EBV(+)-marker methylation. Recombinant EBV was infected to low epigenotype gastric cancer cell, MKN7. In all the three independently established clones, DNA methylation was induced in High- and EBV(+)-markers after 18 weeks, demonstrating that EBV-positive epigenotype should involve methylation of Common-, High-, and EBV(+)-markers simultaneously. The de novo methylated genes were overlapped well among the three clones, and the methylation caused gene repression. In summary, gastric cancer was classified into three DNA methylation epigenotypes, EBV-positive gastric cancer showed markedly high methylation epigenotype expanding to non-PRC target genes, and EBV infection per se could induce the EBV-positive epigenotype.
Classification of Epstein-Barr virus-positive gastric cancers by definition of DNA methylation epigenotypes.
Specimen part, Cell line
View SamplesMediator complex has been known as pivotal regulator of RNA polymerase II. Mediator complex has two CDK subunits in vertebrates, named CDK8 and CDK19. To elucidate functional difference between CDK8 and CDK19 in human cell, we employ siRNA mediate knockdown assay using HeLa S3 cell line. According to this assay these CDKs possess highly redundancy in HeLa S3 cell transcription regulation mechanism but in several genes, each CDK shows gene specific regulatory function.
Identification of target genes for the CDK subunits of the Mediator complex.
Cell line
View SamplesCancer cells express different sets of receptor type tyrosine kinases. These receptor kinases may be activated through autocrine or paracrine mechanisms. Fibroblasts may modify the biologic properties of surrounding cancer cells through paracrine mechansms.
The role of HGF/MET and FGF/FGFR in fibroblast-derived growth stimulation and lapatinib-resistance of esophageal squamous cell carcinoma.
Specimen part, Cell line
View SamplesLoss or reduction in function of tumor suppressor genes contributes to tumorigenesis. We identified a novel homozygous deletion of DACH1 in gliomas.
Homozygously deleted gene DACH1 regulates tumor-initiating activity of glioma cells.
Specimen part, Cell line
View SamplesHOX genes encode a family of homeodomain-containing transcription factors involved in the determination of cell fate and identity during embryonic development. They also behave as oncogenes in some malignancies. In this study, we found high expression of the HOXD9 gene transcript in glioma cell lines and human glioma tissues by quantitative real-time PCR. Using immunocytochemistry, we observed HOXD9 protein expression in human brain tumor tissues, including astrocytomas and glioblastomas. To investigate the role of HOXD9 in gliomas, we silenced its expression in the glioma cell line U87 using HOXD9-specific siRNA, and observed decreased cell proliferation, cell cycle arrest, and induction of apoptosis. It was suggested that HOXD9 contributes to both cell proliferation and/or cell survival. The HOXD9 gene was highly expressed in a side population (SP) of SK-MG-1 cells that was previously identified as an enriched-cell fraction of glioma cancer stem-like cells. HOXD9 siRNA treatment of SK-MG-1 SP cells resulted in reduced cell proliferation. Finally, we cultured human glioma cancer stem cells (GCSCs) from patient specimens found with high expression of HOXD9 in GCSCs compared with normal astrocyte cells and neural stem/progenitor cells (NSPCs). Our results suggest that HOXD9 may be a novel marker of GCSCs and cell proliferation and/or survival factor in gliomas and glioma cancer stem-like cells, and a potential therapeutic target.
Functional analysis of HOXD9 in human gliomas and glioma cancer stem cells.
Cell line
View SamplesMediator complex has been known as pivotal regulator of RNA polymerase II. Mediator complex has two CDK subunits in vertebrates, named CDK8 and CDK19. To elucidate functional difference between CDK8 and CDK19 in human cell, we employ siRNA mediate knockdown assay using HeLa S3 cell line. According to this assay these CDKs possess highly redundancy in HeLa S3 cell transcription regulation mechanism but in several genes, each CDK shows gene specific regulatory function.
Mediator complex recruits epigenetic regulators via its two cyclin-dependent kinase subunits to repress transcription of immune response genes.
Cell line
View Samples