Although an important association between lymph node metastasis and poor prognosis in breast cancer was observed decades ago, an active role for the lymphatic system in metastatic dissemination has only recently been examined. We demonstrate that the Six1 homeoprotein promotes peri- and intra-tumoral lymphangiogenesis, lymphatic invasion, and distant metastasis of breast cancer cells. We identify the pro-lymphangiogenic factor, VEGF-C, as required for this process, and demonstrate transcriptional induction as the mechanism of regulation of VEGF-C expression by Six1. Using a different, but complementary animal model, we show that while required, VEGF-C is not sufficient for the pro-metastatic effects of Six1. Verifying the clinical significance of this pro-metastatic Six1-VEGF-C axis, we demonstrate co-expression of Six1 and VEGF-C in human breast cancer.
SIX1 induces lymphangiogenesis and metastasis via upregulation of VEGF-C in mouse models of breast cancer.
Specimen part, Cell line
View SamplesWe recently described TRIM8, a nuclear E3 ubiquitin ligase, whose expression inversely correlates with glioma grade. TRIM8 restoration suppresses cell growth and induces a significant reduction of clonogenic potential in both U87MG glioblastoma and patients' primary glioma cell lines. Since E3 ubiquitin ligase proteins regulate carcinogenesis through the timely control of many cellular processes such as DNA damage response, metabolism, transcription, and apoptosis, we reasoned that TRIM8 activity might impact on cell transcriptome patterns, thereby promoting cancer development and progression. Therefore, we profiled the whole transcriptome of normal embryonic neural stem cells (eNSC) infected with a retrovirus expressing FLAG-Trim8 by using RNA-Seq. RNA-Seq revealed 1365 differentially expressed transcripts of 912 genes. 723 of them (corresponding to 648 RefSeq genes) differed significantly of at least 1.5 folds (192 upregulated transcripts of 178 genes and 531 downregulated transcripts of 470 genes). 80 genes, among all differentially expressed genes, resulted to significantly enrich 18 pathways by IPA analysis. 53% of these genes (43 out of 80 genes) are related to cell-morphology, cell death and survival, with a preponderantly representation of signaling pathways related to neurotransmission and to CNS, including axonal guidance, GABA Receptor, ephrin B, synaptic long-term potentiation/depression, and glutamate receptor. Specifically, our results substantiate the role of TRIM8 in the brain functions through the dysregulation of genes involved in different pathways, including JAK-STAT. Finally, we provided additional evidence about the existence of a functional interactive crosstalk between TRIM8 and STAT3 with possible implications in the development and progression of glioma. Overall design: Profiling the transcriptome of TRIM8-expressing primary mouse embryonal neural stem cells using RNA-Seq
TRIM8-driven transcriptomic profile of neural stem cells identified glioma-related nodal genes and pathways.
Specimen part, Subject
View SamplesInappropriate activation of developmental pathways is a well-recognized tumor-promoting mechanism. Here we show that overexpression of the homeoprotein Six1, normally a developmentally restricted transcriptional regulator, increases Transforming Growth Factor-beta (TGF-beta) signaling in mammary carcinoma cells and induces an epithelial to mesenchymal transition (EMT) that is in part dependent on its ability to increase TGF-beta signaling. TGF-beta signaling and EMT have been implicated in metastatic dissemination of carcinoma. Using spontaneous and experimental metastasis mouse models, we demonstrate that Six1 overexpression promotes breast cancer metastasis. In addition, we show that, like its induction of EMT, Six1-induced experimental metastasis is dependent on its ability to activate TGF-beta signaling. Importantly, in human breast cancers Six1 significantly correlates with nuclear Smad3, and thus increased TGF-beta signaling. Further, breast cancer patients whose tumors overexpress Six1 have a shortened time to relapse and metastasis, and an overall decrease in survival. Finally, we show that the effects of Six1 on tumor progression likely extend beyond breast cancer, since its overexpression correlates with adverse outcomes in numerous other cancers, including brain, cervical, prostate, colon, kidney, and liver, amongst others. Our findings argue that Six1, acting through TGF-beta signaling and EMT, is a powerful and global promoter of cancer metastasis.
The Six1 homeoprotein induces human mammary carcinoma cells to undergo epithelial-mesenchymal transition and metastasis in mice through increasing TGF-beta signaling.
Cell line
View SamplesEngineering of genetically encoded calcium indicators predominantly focused on optimizing fluorescence changes, but effects of indicator expression on host organisms have largely not been addressed. Here, we report biocompatibility and wide-spread functional expression of the genetically encoded calcium indicator TN-XXL in a transgenic mouse model. To validate the model and to characterize potential effects of indicator expression we assessed both indicator function and a variety of host parameters such as anatomy, physiology, behavior and gene expression profiles in these mice. We also demonstrate the usefulness of primary cell types and organ explants prepared from these mice for imaging applications. While we do find mild signatures of indicator expression that may guide further indicator development the green indicator mice generated provide a well characterized resource of primary cells and tissues for in vitro and in vivo calcium imaging applications.
Biocompatibility of a genetically encoded calcium indicator in a transgenic mouse model.
Specimen part
View SamplesThe study was completed to compare expression profiles of primary human beta cells (in the form of adult human islets), to the expression profile of hESC-derived beta-like cells. A HES3 line modified by homologous recombination to express GFP under the insulin promoter allowed us to FACS sort the hESC-derived cells into purified insulin-positive (presumably beta-like cells), and insulin-negative populations.
The functional and molecular characterisation of human embryonic stem cell-derived insulin-positive cells compared with adult pancreatic beta cells.
Specimen part
View SamplesTP53 is mutated in 50% of all cancers, and is often functionally compromised in cancers where it is not mutated. We demonstrate that the pro-tumorigenic/metastatic Six1 homeoprotein decreases p53 levels through a mechanism that does not involve the negative regulator of p53, MDM2. Instead, Six1 regulates p53 via a dual mechanism involving upregulation of microRNA-27a and downregulation of the ribosomal protein L26 (RPL26), a positive regulator of p53 translation. Mutation analysis confirms that RPL26, whose expression inversely correlates with Six1 expression in numerous tumor types, inhibits miR-27a binding to the p53 3UTR and prevents microRNA-mediated translational inhibition of p53. Thus, through simultaneous downregulation of RPL26 and upregulation of miR-27a, Six1 efficiently lowers p53 levels despite regulation of p53 at the level of the proteasome. Consequently, Six1 overexpression, which is observed in numerous tumor types, leads to dramatic resistance to nutlins, as well as other therapies targeting the p53-MDM2 interaction.
The Six1 oncoprotein downregulates p53 via concomitant regulation of RPL26 and microRNA-27a-3p.
Specimen part, Treatment
View SamplesComparative microarray-based transcriptome analysis of A. thaliana mlo2 mlo6 mlo12 mutants and wild type plants upon Golovinomyces orontii inoculation revealed an increased and accelerated accumulation of many defense-related transcripts. Despite the biotrophic nature of the interaction, this included the non-canonical activation of a jasmonic acid/ethylene-dependent transcriptional program.
Key Components of Different Plant Defense Pathways Are Dispensable for Powdery Mildew Resistance of the Arabidopsis <i>mlo2 mlo6 mlo12</i> Triple Mutant.
Specimen part, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
7q11.23 dosage-dependent dysregulation in human pluripotent stem cells affects transcriptional programs in disease-relevant lineages.
Sex, Specimen part, Subject
View SamplesWe apply the cellular reprogramming experimental paradigm to two disorders caused by symmetrical copy number variations (CNV) of 7q11.23 and displaying a striking combination of shared as well as symmetrically opposite phenotypes: Williams Beuren syndrome (WBS) and 7q microduplication syndrome (7dup). Through a uniquely large and informative cohort of transgene-free patient-derived induced pluripotent stem cells (iPSC), along with their differentiated derivatives, we find that 7q11.23 CNV disrupt transcriptional circuits in disease-relevant pathways already at the pluripotent state. These alterations are then selectively amplified upon differentiation into disease-relevant lineages, thereby establishing the value of large iPSC cohorts in the elucidation of disease-relevant developmental pathways. In addition, we functionally define the quota of transcriptional dysregulation specifically caused by dosage imbalances in GTF2I (also known as TFII-I), a transcription factor in 7q11.23 thought to play a critical role in the two conditions, which we found associated to key repressive chromatin modifiers. Finally, we created an open-access web-based platform (accessible at http://bio.ieo.eu/wbs/ ) to make accessible our multi-layered datasets and integrate contributions by the entire community working on the molecular dissection of the 7q11.23 syndromes.
7q11.23 dosage-dependent dysregulation in human pluripotent stem cells affects transcriptional programs in disease-relevant lineages.
Sex, Specimen part, Subject
View SamplesRNAPII pausing/termination shortly after initiation is a hallmark of gene regulation. However, the molecular mechanisms involved are still to be uncovered. Here, we show that NELF interacts with Integrator complex subunits (INTScom) forming a stable complex with RNPII and Spt5. The interaction between NELF and INTScom subunits is RNA and DNA independent. Using both HIV-1 promoter and genome wide analyses, we demonstrate that Integrator subunits specifically control NELF-mediated RNAPII pause/release at coding genes. The strength of RNAPII pausing is determined by the nature of the NELF-associated complex. Interestingly, in addition to controlling RNAPII pause release INTS11 catalytic subunit of the INTScom is required for the synthesis of full length mRNA. Finally, INTScom-target genes are enriched in HIV-1 TAR/ NELF-binding element and in a 3'box sequence required for snRNA biogenesis. Revealing these unexpected functions of INTScom in regulating RNAPII pausing/release and completion of mRNA synthesis of NELF-target genes will contribute to our understanding of the gene expression cycle. Overall design: Genome-wide expression in HeLa cells in the absence of Integrator 11, or NELF or mock (control) depleted by strand-specific RNASeq (Illumina)
Integrator complex regulates NELF-mediated RNA polymerase II pause/release and processivity at coding genes.
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