Grainyhead genes are involved in wound healing and developmental neural tube closure. In light of the high degree of similarity between the epithelial-mesenchymal transitions (EMTs) occurring in wound healing processes and the cancer stem cell-like compartment of tumors, including TGF--dependence, we investigated the role of a Grainyhead gene (GRHL2) in oncogenic EMT. Grainyhead was specifically down-regulated in the claudin-low subclass of mammary tumors and in the basal-B subclass of breast cancer cell lines. Functionally, GRHL2 suppressed TGF--induced, Twist-induced or spontaneous EMT, enhanced anoikis-sensitivity, and suppressed mammosphere generation in mammary epithelial cells. These effects were mediated, in part, by its suppression of ZEB1 expression, through direct repression of the ZEB1 promoter. GRHL2 also inhibited Smad-mediated transcription, and up-regulated mir200b/c as well as the TGF- receptor antagonist, BMP2. The expression of GRHL2 in the breast cancer cell line MDA-MB-231 triggered a mesenchymal-to-epithelial transition and sensitized the cells to anoikis. These results indicate that GRHL2 is a suppressor of the oncogenic EMT.
Suppression of the epithelial-mesenchymal transition by Grainyhead-like-2.
Specimen part
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Systematic classification of melanoma cells by phenotype-specific gene expression mapping.
Cell line
View SamplesRecent trials with MAPK inhibitors have shown promising results in many patients with metastatic melanoma; however, nearly all responding patients experience disease relapse. We describe here how melanoma cells respond to MAPK inhibition in a phenotype-specific manner, suggesting that slow cycling invasive phenotype cells provide a treatment-resistant pool from which disease relapse may be derived. The implication is that while MAPK inhibition may successfully treat proliferating cells, another cell population needs to be addressed at the same time.
A proliferative melanoma cell phenotype is responsive to RAF/MEK inhibition independent of BRAF mutation status.
Cell line
View SamplesSOX9 is generally not expressed in melanomas with a high proliferative capacity but is expressed in melanomas with a high invasive capacity. Here we overexpress full length SOX9 in M010817, a melanoma cell culture with high proliferative capacity but low invasive capacity.
Methylation-dependent SOX9 expression mediates invasion in human melanoma cells and is a negative prognostic factor in advanced melanoma.
Specimen part, Cell line
View SamplesWe hypothesize that changes in adrenal gene expression mediate the increased plasma corticosterone and steroidogenesis in rat pups exposed to hypoxia from birth.
Microarray and real-time PCR analysis of adrenal gland gene expression in the 7-day-old rat: effects of hypoxia from birth.
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View SamplesHigh-density lipoproteins (HDLs) protect pancreatic cells against apoptosis. This property might be related to the increased risk to develop diabetes in patients with low HDL blood levels. However, the mechanisms by which HDLs protect cells are poorly characterized. Here we use a transcriptomic approach to identify genes differentially modulated by HDLs in cells subjected to apoptotic stimuli.
Involvement of 4E-BP1 in the protection induced by HDLs on pancreatic beta-cells.
Specimen part, Cell line
View SamplesExtracellular, cancer-specific methylated DNA has been shown to be a prognostic marker when detected in serum or plasma. In this study we investigated the effect of treating cancer cells with differentially methylated CpG DNA. When breast cancer cell lines were treated with methylated CpG DNA, a consistent upregulation of CHAC1 mRNA expression was observed. CHAC1 was recently described to be a novel component of the unfolded protein response pathway. To elucidate the role of CHAC1 mRNA expression in cancer in more detail, we analyzed expression of this gene in breast (n=107) and ovarian cancer (n=107) and found a strong correlation with tumor differentiation. Poorly differentiated tumors exhibited higher CHAC1 expression levels (p=0.004 for breast and p=0.031 for ovarian cancer). Additionally, hormone receptor (HR)-negative breast cancers (p<0.001) and advanced stage disease ovarian cancers (p=0.026) also demonstrated high CHAC1 mRNA levels. mRNA expression analysis of the two known CHAC1 isoforms showed a strong association of expression above the median with poor outcome in breast cancer patients in a multivariate analysis (isoform a: relative risk (RR) of death 3.2 (95% CI 1.6-6.5; p<0.01); RR of relapse 3.9 (95% CI 1.6-9.8; p<0.01); isoform b: relative risk (RR) of death 3.5 (95% CI 1.6-7.3; p<0.01); RR of relapse 6.6 (95% CI 2.4-18.5; p<0.01)). Univariate analysis in ovarian cancer showed that CHAC1 mRNA expression above the median was associated with a poor relapse free survival (p=0.03). In younger ovarian cancer patients (age < median age), a high CHAC1 mRNA expression was associated with overall survival (p=0.007) and relapse free survival (p=0.015). Finally, we show that downregulation of CHAC1 by small interfering RNA suppressed breast cancer cell migration and proliferation, whereas overexpression resulted in an observed increase in these cellular behaviours. This is the first report demonstrating that a gene (CHAC1) whose expression is triggered by methylated, but not unmethylated DNA, is involved in tumour biology.
Elevated mRNA expression of CHAC1 splicing variants is associated with poor outcome for breast and ovarian cancer patients.
Specimen part, Cell line, Treatment
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The lncRNA HOTAIR impacts on mesenchymal stem cells via triple helix formation.
Specimen part, Treatment
View SamplesLong non coding RNAs are implemented in epigenetic changes and regulation of gene expression. HOTAIR is a promising lncRNA concerning epigenetic regulation. We performed HOTAIR overexpression and knockdown experiments in mesenchymal stromal cells derived from bone marrow. After two weeks cells were harvested and RNA and DNA were isolated. Analysis of gene expression was performed with Human Gene 2.0 ST Array (Affymetrix, Santa Clara, USA). Analysis of DNA methylation was performed with Infinium HumanMethylation450 BeadChips (Illumina, San Diego, USA)
The lncRNA HOTAIR impacts on mesenchymal stem cells via triple helix formation.
Specimen part, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
PI3K-targeted therapy can be evaded by gene amplification along the MYC-eukaryotic translation initiation factor 4E (eIF4E) axis.
Specimen part
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