The animal piRNA pathway is a small RNA silencing system that acts in gonads and protects the genome against the deleterious influence of transposons. A major bottleneck in the field is the lack of comprehensive knowledge of the factors and molecular processes that constitute this pathway. We conducted an RNAi screen in Drosophila and identified ~50 genes that strongly impact the ovarian somatic piRNA pathway. Many identified genes fall into functional categories that indicate essential roles for mitochondrial metabolism, RNA export, the nuclear pore, transcription elongation and chromatin regulation in the pathway. Follow-up studies on two factors demonstrate the identification of components acting at distinct hierarchical levels of the pathway. Finally, we define CG2183/Gasz as a novel primary piRNA biogenesis factor in somatic and germline cells. Based on the similarities between insect and vertebrate piRNA pathways our results have far-reaching implications for the understanding of this conserved genome defense system. Overall design: Steady-state RNA levels in wild-type ovarian somatic cells (OSC) and RNAi knock-downs of the piRNA pathway components.
The genetic makeup of the Drosophila piRNA pathway.
Specimen part, Subject
View SamplesKaposi sarcoma is the most common cancer in AIDS patients and is typified by red skin lesions. The disease is caused by the KSHV virus (HHV8) and is recognizable by its distinctive red skin lesions. The lesions are KSHV infected spindle cells, most commonly the lymphatic endothelial and blood vessel endothelial cells (LEC and BEC), plus surrounding stroma. Here we examine KSHVs modulation of Notch signaling using wild-type LEC cells co-cultured with DLL4 and JAG1 expressing LEC cells.
KSHV manipulates Notch signaling by DLL4 and JAG1 to alter cell cycle genes in lymphatic endothelia.
No sample metadata fields
View Sampleseffect of overexpression of GATA-6 in P19 CL6 induced cells
Wnt2 is a direct downstream target of GATA6 during early cardiogenesis.
Cell line
View SamplesOvarian cancer patients are generally diagnosed at stage III/IV, when ascites is common. The volume of ascites positively correlates with the extent of metastasis and negatively with prognosis. Membrane GRP78, a stress-inducible endoplasmic reticulum chaperone which also appears on the plasma membrane (memGRP78) of aggressive cancers, plays a crucial role in the maintenance of embryonic stem cells. Our present study demonstrates that tumor cells isolated from ascites generated by epithelial ovarian cancer (ID8 cells) bearing mice have increased memGRP78 expression compared to ID8 cells in normal culture. We hypothesize that these ascites associated memGRP78+ cells are cancer stem-like cells (CSC) and memGRP78 is functionally important in CSCs. Supporting this hypothesis, we show that memGRP78+ cells isolated from ascites have increased sphere forming and tumor initiating abilities compared to memGRP78- cells. When the tumor microenvironment is recapitulated by adding ascites fluid to cell culture, ID8 cells express more memGRP78 and increased self-renewing ability compared to those cultured in medium alone. Moreover, compared to their counterparts cultured in normal medium, ID8 cells cultured in ascites, or isolated from ascites, show an increased expression of stem cell markers Sca-1, Snail and SOX9. Importantly, antibodies directed against the carboxy (COOH)-terminal domain of GRP78 significantly reduce the self-renewing ability of murine and human ovarian cancer cells pre-incubated with ascites, associated with a decreased phosphorylation of Akt and GSK3, and reduced level of the transcriptional factor Snail. Based on this data, we suggest that memGRP78 is a logical therapeutic target for late stage ovarian cancer.
Syngeneic Murine Ovarian Cancer Model Reveals That Ascites Enriches for Ovarian Cancer Stem-Like Cells Expressing Membrane GRP78.
Disease
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The DNA double-strand break response is abnormal in myeloblasts from patients with therapy-related acute myeloid leukemia.
Specimen part, Disease stage
View SamplesIn order to examine if the upregulation of DNA repair genes on chromosome 8 was associated with the abnormal DSB phenotype observed in trisomy 8 (defined by array CGH or cytogenetics), we compared the mRNA levels of DNA repair genes on chromosome 8 in trisomy 8 t-AML patients versus normal t-AML gammaH2AX responders using gene expression array data.
The DNA double-strand break response is abnormal in myeloblasts from patients with therapy-related acute myeloid leukemia.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Effects of warm ischemic time on gene expression profiling in colorectal cancer tissues and normal mucosa.
Specimen part, Disease, Disease stage, Subject, Time
View SamplesThe study outcome was to evaluate the effect of the time on normal colon mucosa samples and possibly select specific genes whose expression is time-related, that could be used as detectors of tissue degradation.
Effects of warm ischemic time on gene expression profiling in colorectal cancer tissues and normal mucosa.
Specimen part, Disease, Disease stage, Subject, Time
View SamplesThe study outcome was to evaluate the effect of the time on tumor samples and possibly select specific genes whose expression is time-related, that could be used as detectors of tissue degradation.
Effects of warm ischemic time on gene expression profiling in colorectal cancer tissues and normal mucosa.
Specimen part, Disease, Disease stage, Subject, Time
View Samples[original title] LMP-420: a novel purine nucleoside analogue with potent cytotoxic effects for chronic lymphocytic leukemia cells and minimal toxicity for normal hematopoietic cells.
LMP-420: a novel purine nucleoside analog with potent cytotoxic effects for CLL cells and minimal toxicity for normal hematopoietic cells.
No sample metadata fields
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