Expression was generated on tumors from 41 iBIP mice, which were previously described (Kwong, JCI, 2015).
Oncogenic BRAF-Mediated Melanoma Cell Invasion.
Specimen part
View SamplesTargeting components of the mitogen-activated protein kinase (MAPK) pathway prolongs survival of patients with advanced BRAFV600E melanomas but such an approach is not curative because of the rapid acquisition of numerous resistance mechanisms. Here we analyze melanoma cells that evade MAPK inhibitors by undergoing a senescence-like, slow-growth, phenotype, which leads to acquired resistance. The initial therapeutic response is characterized by an integrated stress response program, including stimulation of autophagic flux, activation of the endoplasmic reticulum machinery, and an enhanced ability of detoxifying reactive oxygen species. Reversibly senescent cells also exhibit an increase in mitochondrial genome copy number and a strong metabolic shift towards oxidative phosphorylation (OxPhos). Inducing mitochondrial dysfunction by co-targeting the MAPK pathway and mitochondrial Hsp90-directed protein folding with specific inhibitors prevented entry of cells into a reversibly senescent state, suppressed mitochondrial energy metabolism and augmented therapy response.
Targeting mitochondrial biogenesis to overcome drug resistance to MAPK inhibitors.
Disease, Disease stage, Cell line, Time
View SamplesIPH-926 is an anticancer drug-resistant tumor cell line derived from a chemo-refractory human infiltrating lobular breast cancer (ILBC). IPH-926 ILBC cells were subjected to gene expression profiling using an Affymetrix HG U133 Plus 2.0 array.
ABCB1/MDR1 contributes to the anticancer drug-resistant phenotype of IPH-926 human lobular breast cancer cells.
Specimen part, Cell line
View SamplesHuman solid tumors contain rare cancer side population (SP) cells, which expel the fluorescencent dye H33342 and display cancer stem cell characteristics. Transcriptional profiling of cancer SP cells isolated by H33342 fluorescence analysis is a newly emerging approach to discover cancer stem cell markers and aberrant differentiation pathways. Using Affymetrix expression microarrays this study investigated differential gene expression between SP and non-SP (NSP) cells isolated from the CAL-51 human mammary carcinoma cell line.
Down-regulation of the fetal stem cell factor SOX17 by H33342: a mechanism responsible for differential gene expression in breast cancer side population cells.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Dnmt3L antagonizes DNA methylation at bivalent promoters and favors DNA methylation at gene bodies in ESCs.
Specimen part, Cell line
View SamplesThe de novo DNA methyltransferase 3-like (Dnmt3L) is a catalytically inactive DNA methylase that has been previously shown to cooperate with Dnmt3a and Dnmt3b to methylate DNA. Dnmt3L is highly expressed in mouse embryonic stem cells (ESC) but its function in these cells is unknown. We here report that Dnmt3L is required for the differentiation of ESC into primordial germ cells (PGC) through activation of the homeotic gene Rhox5. By genome-wide analysis we found that Dnmt3L is a positive regulator of methylation at gene bodies of housekeeping genes and a negative regulator of methylation at promoters of bivalent genes. We demonstrate that Dnmt3L interacts with the Polycomb PRC2 complex in competition with the DNA methyl transferases Dnmt3a and Dnmt3b to maintain low the methylation level at H3H27me3 regions. Thus in ESC, Dnmt3L counteracts the activity of de novo DNA methylases to keep low the level of DNA methylation at developmental gene promoters.
Dnmt3L antagonizes DNA methylation at bivalent promoters and favors DNA methylation at gene bodies in ESCs.
Specimen part
View SamplesTen eleven translocation (TET) enzymes catalyse the oxidative reactions of 5-methylcytosine (5mC) to promote the demethylation process. The reaction intermediate 5-hydroxymethylcytosine (5hmC) has been shown to be abundant in embryonic stem cells and tissues, but strongly depleted in human cancers. Genetic mutations of TET2 gene were associated with lleukemia, whereas TET1 downregulation has been shown to promote malignancy in breast cancer. Here, we report that TET1 is downregulated in colon tumours from the initial stage. TET1 silencing in primary epithelial colon cells increase their cellular proliferation while its re-expression in colon cancer cells inhibits their proliferation and the growth of tumour xenografts even at later stages. We found that TET1 binds and maintains hypomethylated the promoter of the DKK genes inhibitors of the WNT signalling to promote their expression. Downregulation of TET1 during colon cancer initiation leads to repression, by DNA methylation the promoters of the inhibitors of the WNT pathway resulting in a constitutive activation of the WNT pathway. Thus the DNA hydroxymethylation mediated by TET1 controlling the WNT signalling is a key player of tumour growth. These results provide new insights for understanding how tumours escape cellular controls Overall design: Transcriptome analysis of Caco-2 cell line expressing TET1 protein.
TET1 is a tumour suppressor that inhibits colon cancer growth by derepressing inhibitors of the WNT pathway.
No sample metadata fields
View SamplesHypoxia is an important condition in the tumor cell microenvironment and approximately 1-1.5% of the genome is transcriptionally responsive to hypoxia with hypoxia-inducible factor-1 (HIF-1) as a major mediator of transcriptional activation. Tumor hypoxia is associated with a more aggressive phenotype of many cancers in adults, but data on pediatric tumors are scarce. By immunohistochemical analysis, HIF-1 expression was readily detectable in 18/28 primary Ewings sarcoma family tumors (ESFT), a group of highly malignant bone-associated tumors in children and young adults, which encouraged us to study the effect of hypoxia on ESFT cell lines in vitro.
Hypoxia modulates EWS-FLI1 transcriptional signature and enhances the malignant properties of Ewing's sarcoma cells in vitro.
Disease, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Characterization of genomic imbalances in diffuse large B-cell lymphoma by detailed SNP-chip analysis.
Sex, Age
View SamplesThe pathogenesis of diffuse large B cell lymphomas (DLBCL) is only partly understood. We analyzed 148 DLBCL by high resolution single nucleotide polymorphism (SNP)-chips to characterize genomic imbalances. Seventy-nine cases were of the germinal center B-cell like (GCB) type of DLBCL, 49 of the activated B-cell like (ABC) subtype and 20 were type 3 DLBCL. Twenty-four regions of recurrent genomic gains and 38 regions of recurrent genomic losses were identified over the whole cohort, with a median of 25 imbalances per case for ABC-DLBCL and 19 per case for GCB-DLBCL. Several recurrent copy number changes showed differential frequencies in the GCB- and ABC-DLBCL subgroups, including gains of HDAC7A predominantly in GCB-DLBCL (38% of cases) and losses of BACH2 and CASP8AP2 predominantly in ABC-DLBCL (35%), hinting at disparate pathogenetic mechanisms in these entities. Correlating gene expression and copy number revealed a strong gene dosage effect in all tumors, with 34% of probesets showing a concordant expression change in affected regions. Two new potential tumor suppressor genes emerging from the analysis, CASP3 and IL5RA, were sequenced in 10 and 16 candidate cases, respectively. However, no mutations were found, pointing to a potential haploinsufficiency effect of these genes, considering their reduced expression in cases with deletions. This work thus describes differences and similarities in the landscape of genomic aberrations in the DLBCL subgroups in a large collection of cases, confirming already known targets, but also discovering novel copy number changes with possible pathogenetic relevance.
Characterization of genomic imbalances in diffuse large B-cell lymphoma by detailed SNP-chip analysis.
Sex, Age
View Samples