Inducible overexpression of Arabidopsis meristem regulators by AlcR / AlcA system. Plants harboring 35S::AlcR/AlcA::GOI (GUS control, LEAFY, SHOOTMERSTEMLESS, WUSCHEL)constructs were grown in continous light for 12 days and induced with 1% Ethanol. After 12h of EtOH treatment, seedlings were dissected and RNA was processed from the shoot apex and young leaves. Affymetrix Ath1 arrays were hybridized in duplicates from each experiment.
WUSCHEL controls meristem function by direct regulation of cytokinin-inducible response regulators.
Age, Specimen part, Subject, Compound
View SamplesPrimary tumor growth induces host tissue responses that are believed to support and promote tumor progression. Identification of the molecular characteristics of the tumor microenvironment and elucidation of its crosstalk with tumor cells may therefore be crucial for improving our understanding of the processes implicated in cancer progression, identifying potential therapeutic targets, and uncovering stromal gene expression signatures that may predict clinical outcome. A key issue to resolve, therefore, is whether the stromal response to tumor growth is largely a generic phenomenon, irrespective of the tumor type, or whether the response reflects tumor-specific properties. To address similarity or distinction of stromal gene expression changes during cancer progression, oligonucleotide-based Affymetrix microarray technology was used to compare the transcriptomes of laser-microdissected stromal cells derived from invasive human breast and prostate carcinoma. Invasive breast and prostate cancer-associated stroma was observed to display distinct transcriptomes, with a limited number of shared genes. Interestingly, both breast and prostate tumor-specific dysregulated stromal genes were observed to cluster breast and prostate cancer patients, respectively, into two distinct groups with statistically different clinical outcomes. By contrast, a gene signature that was common to the reactive stroma of both tumor types did not have survival predictive value. Univariate Cox analysis identified genes whose expression level was most strongly associated with patient survival. Taken together, these observations suggest that the tumor microenvironment displays distinct features according to the tumor type that provides survival-predictive value.
Identification of prognostic molecular features in the reactive stroma of human breast and prostate cancer.
Specimen part
View SamplesMetastasis depends on the ability of tumor cells to establish a relationship with the newly seeded host tissue that is conducive to their survival and proliferation. Recent evidence suggests that tumor cells regulate their own dissemination by preparing permissive metastatic niches within host tissues. However, the factors that are implicated in rendering tissues permissive for metastatic tumor growth have yet to be fully elucidated. Breast tumors arising during pregnancy display highly aggressive behaviour and early metastatic proclivity, raising the possibility that pregnancy may constitute a physiological condition of permissiveness for tumor dissemination. We show that during murine gestation, both the rate and degree of metastatic tumor growth are enhanced irrespective of tumor type and that decreased natural killer (NK) cell activity is responsible for the observed increase in experimental metastasis. We identify gene expression changes in pregnant mouse lung and liver that bear striking similarity with reported pre-metastatic niche signatures and several of the up-regulated genes are indicative of myeloid-cell infiltration. We provide evidence, that CD11b+ Gr-1+ myeloid-derived suppressor cells accumulate in pregnant mice and exert an inhibitory effect on NK cell activity, thereby enhancing metastatic tumor growth. MDSC have never been evoked in the context of pregnancy and our observations suggest that they may represent a further shared mechanism of immune suppression occurring during gestation and tumor growth.
Myeloid-derived suppressor cells are implicated in regulating permissiveness for tumor metastasis during mouse gestation.
Specimen part
View SamplesMaintaining cell fate relies on robust mechanisms that prevent the differentiation of specified cells into other cell types. This is especially critical during embryogenesis, when extensive cell proliferation, patterning and migration events take place. Here we show that vertebrate primordial germ cells (PGCs) are protected from reprogramming into other cell types by the RNA-binding protein Dead end (Dnd). PGCs knocked down for Dnd lose their characteristic morphology and adopt that of various somatic cell types. Concomitantly, they gain a gene expression profile reflecting differentiation into cells of different germ layers, in a process that we could direct by expression of specific cell-fate determinants. Importantly, we visualized these events within live zebrafish embryos, which provide temporal information regarding cell reprogramming. Our results shed light on the mechanisms controlling germ cell fate maintenance and are relevant for the formation of teratoma, a tumor class composed of cells from more than one germ layer. Overall design: Transcriptome profiling of 13hpf sorted germ cells of zebrafish embryos injected with either control or dead end Morpholino
The Vertebrate Protein Dead End Maintains Primordial Germ Cell Fate by Inhibiting Somatic Differentiation.
Specimen part, Cell line, Subject
View SamplesThe biology of chronic myeloid leukemia (CML)-stem cells is still incompletely understood. Therefore, we previously developed an inducible transgenic mouse model in which stem cell targeted induction of BCR-ABL expression leads to chronic phase CML-like disease. Here, we now demonstrate that the disease is transplantable using BCR-ABL positive LSK cells (lin-Sca-1+c-kit+). Interestingly, the phenotype is enhanced when unfractionated bone marrow (BM) cells are transplanted. However, neither progenitor cells (lin-Sca-1-c-kit+) nor mature granulocytes (CD11b+Gr-1+), or potential stem cell niche cells were able to transmit the disease or alter the phenotype. The phenotype was largely independent of BCR ABL priming prior to transplant. However, BCR-ABL abrogated the potential of LSK cells to induce full blown disease in secondary recipients. Subsequently, we found that BCR-ABL increased the fraction of multipotent progenitor cells (MPP) at the expense of long term HSC (LT-HSC) in the BM. Microarray analyses of LSK cells revealed that BCR-ABL alters the expression of genes involved in proliferation, survival, and hematopoietic development. Our results suggest that BCR-ABL induces differentiation of LT-HSC and decreases their self renewal capacity. Furthermore, reversion of BCR-ABL eradicates mature cells while leukemic stem cells persist, giving rise to relapsed CML upon re-induction of BCR-ABL.
BCR-ABL enhances differentiation of long-term repopulating hematopoietic stem cells.
Specimen part
View SamplesRCC cells (786-O) were transfected with VHL. The parental cell line should be compared to the transfectant (+VHL) under nomoxia as well as under hypoxia conditions.
Distinct von Hippel-Lindau gene and hypoxia-regulated alterations in gene and protein expression patterns of renal cell carcinoma and their effects on metabolism.
Cell line
View SamplesMouse and human stem cells with features similar to those of embryonic stem cells have been derived from testicular cells. Although pluripotent stem cells have been obtained from defined germline stem cells (GSCs) of mouse neonatal testis, only multipotent stem cells have been obtained so far from defined cells of mouse adult testis. In this study we describe a robust and reproducible protocol for obtaining germline-derived pluripotent stem (gPS) cells from adult unipotent GSCs. Pluripotency of gPS cells was confirmed by in vitro and in vivo differentiation, including germ cell contribution and transmission. As determined by clonal analyses, gPS cells indeed originate from unipotent GSCs. We propose that the conversion process requires a GSC culture microenvironment that depends on the initial number of plated GSCs and the length of culture time.
Induction of pluripotency in adult unipotent germline stem cells.
No sample metadata fields
View SamplesMouse and human stem cells with features similar to those of embryonic stem cells have been derived from testicular cells. Although pluripotent stem cells have been obtained from defined germline stem cells (GSCs) of mouse neonatal testis, only multipotent stem cells have been obtained so far from defined cells of mouse adult testis. In this study we describe a robust and reproducible protocol for obtaining germline-derived pluripotent stem (gPS) cells from adult unipotent GSCs. Pluripotency of gPS cells was confirmed by in vitro and in vivo differentiation, including germ cell contribution and transmission. As determined by clonal analyses gPS cells indeed originate from unipotent GSCs. We propose that the conversion process requires a GSC culture microenvironment that depends on the initial number of plated GSCs and the length of culture time.
Induction of pluripotency in adult unipotent germline stem cells.
Specimen part
View SamplesOverexpression of the Polycomb group protein Enhancer of Zeste Homolog 2 (EZH2) occurs in diverse malignancies, including prostate cancer, breast cancer, and glioblastoma multiforme (GBM) (1). Based on its ability to modulate transcription of key genes implicated in cell cycle control, DNA repair and cell differentiation, EZH2 is believed to play a crucial role in tissue-specific stem cell maintenance and tumor development. Here we show that targeted pharmacologic disruption of EZH2 by the S-adenosylhomocysteine hydrolase inhibitor 3-Deazaneplanocin A (DZNep), or its specific down-regulation by shRNA, strongly impairs GBM cancer stem cell self-renewal in vitro and tumor-initiating capacity in vivo. Using genome-wide expression analysis of DZNep-treated GBM cancer stem cells, we found the expression of c-myc, recently reported to be essential for GBM cancer stem cells, to be strongly repressed upon EZH2 depletion. Specific shRNA-mediated down-regulation of EZH2 in combination with chromatin immunoprecipitation (ChIP) experiments revealed that c-myc is a direct target of EZH2 in GBM cancer stem cells. Taken together, our observations provide evidence that direct transcriptional regulation of c-myc by EZH2 may constitute a novel mechanism underlying GBM cancer stem cell maintenance and suggest that EZH2 may be a valuable new therapeutic target for GBM management.
EZH2 is essential for glioblastoma cancer stem cell maintenance.
Specimen part, Treatment
View SamplesTo investigate the impact of ablating Bcl9/Bcl9l on tumorigenesis, 6-8- week-old mice were exposed first to a single dose dimethylhydrazine (DMH, 44 mg/kg body weight), which is metabolized in the liver to carcinogenic azoxymethane (AOM), followed by 7 days oral administration of 2 % dextrane sulfate sodium (DSS) in the drinking water. This regimen results in the emergence of dysplastic adenomas, which progress to differentiated adenocarcinomas that are morphologically similar to human colorectal adenocarcinomas and typically harbor -catenin stabilizing mutations of GSK3 phosphorylation sites. Accordingly, these tumors present hallmarks of active Wnt signaling such as accumulation of nuclear -catenin and expression of Wnt target genes.
Bcl9/Bcl9l are critical for Wnt-mediated regulation of stem cell traits in colon epithelium and adenocarcinomas.
No sample metadata fields
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