C2C12 cells are mouse skeletal muscle cells. These cells were transfected with shRNA against FoxO1, FoxO3, and FoxO4. FoxO1, FoxO3, and FoxO4 are the known paralogues expressed in this cell line.
Codependent activators direct myoblast-specific MyoD transcription.
No sample metadata fields
View SamplesLKB1 encodes a Ser/Thr kinase and acts as an evolutionarily conserved sensor of cellular energy status in eukaryotic cells. LKB1 functions as the major upstream kinase to phosphorylate AMPK and 12 other AMPK-related kinases, which is required for their activation in many cellular contexts. Once activated, AMPK and AMPK-related kinases phosphorylate a diverse array of downstream effectors to switch on ATP-generating catabolic processes and switch off ATP-consuming anabolic processes, thus restoring energy balance during periods of energetic stress. To study the role and mechanisms of Lkb1 in the regulation of hematopoietic stem cell (HSC) biology, we performed transcriptome analysis of sorted LSK (Lin-, Sca-1+, c-Kit+) cells from Lkb1 WT and KO bone marrows at 1 day post-completing tamoxifen injection (DPI). To identify more proximal molecular effects, we chose 1 DPI due to the modest phenotypes in Lkb1 KO mice, yet documentation of efficient Lkb1 deletion in LSK cells at this very early time point.
Lkb1 regulates quiescence and metabolic homeostasis of haematopoietic stem cells.
Specimen part
View SamplesCritically short telomeres activate cellular senescence or apoptosis, as mediated by the tumor suppressor p53, but in the absence of this checkpoint response, telomere dysfunction engenders chromosomal aberrations and cancer. Here, analysis of p53-regulated genes activated in the setting of telomere dysfunction identified Zfp365 (ZNF365 in humans) as a direct p53 target that promotes genome stability. Germline polymorphisms in the ZNF365 locus are associated with increased cancer risk, including those associated with telomere dysfunction. On the mechanistic level, ZNF365 suppresses expression of a subset of common fragile sites (CFS) including telomeres. In the absence of ZNF365, defective telomeres engage in aberrant recombination of telomere ends, leading to increased telomere sister chromatid exchange (T-SCE) and formation of anaphase DNA bridges, including ultra-fine DNA bridges (UFB), and ultimately increased cytokinesis failure and aneuploidy. Thus, the p53-ZNF365 axis contributes to genomic stability in the setting of telomere dysfunction.
ZNF365 promotes stability of fragile sites and telomeres.
Disease, Cell line, Treatment, Time
View SamplesUnder stress conditions mammalian cells activate compensatory mechanisms to survive and maintain cellular function. During catabolic conditions, such as low nutrients, systemic inflammation, cancer or infections, protein breakdown is enhanced and aminoacids are released from muscles to sustain liver gluconeogenesis and tissues protein synthesis. Proteolysis in muscle is orchestrated by a set of genes named atrophy-related genes. A system that is activated both in short and prolonged stress conditions is the family of Forkhead Box (Fox) O transcription factors. Here, we report that muscle-specific deletion of FoxO members resulted in protection from muscle loss because FoxO family is required for induction of autophagy-lysosome and ubiquitin-proteasome systems. Importantly, FoxOs are required for Akt activity but not for mTOR signalling underlining the concept that FoxOs are upstream mTOR for the control of protein breakdown when nutrients are lacking. Moreover, FoxO family controls the induction of critical genes belonging to several fundamental stress response pathways such as unfolded protein response, ROS detoxification and translational regulation. Finally, we identify a set of novel FoxO-dependent ubiquitin ligases including the recent discovered MUSA11 and a new one, which we named Specific of Muscle Atrophy and Regulated by Transcription (SMART). Our findings identify the critical role of FoxO in regulating a variety of genes belonging to pathways important for stress-response under catabolic conditions.
Regulation of autophagy and the ubiquitin-proteasome system by the FoxO transcriptional network during muscle atrophy.
Sex
View SamplesTo investigate the role of FoxO transcription factors as mediators of hematopoietic stem cell resistance to oxidative stress.
FoxOs are critical mediators of hematopoietic stem cell resistance to physiologic oxidative stress.
No sample metadata fields
View SamplesMicroRNAs have emerged as major genetic elements in the genesis and suppression of cancer. Here, multi-dimensional cancer genome analysis and validation has defined a novel Glioblastoma Multiforme (GBM) tumor suppressor pathway and mechanism of action centered on Quaking (QK), a member of the STAR family of RNA-binding proteins. Combined functional, biochemical and computational studies establish that p53 directly regulates QK gene expression, QK protein binds and stabilizes miR-20a of the cancer-relevant miR-17-92 cluster, and miR-20a in turn functions to regulate TGFR2 and the TGF signaling network. Linkage of these pathway components is supported by their genome and expression status across GBM specimens and by their gain- and loss-of-function interactions in in vitro and in vivo complementation studies. This p53-QK-miR-20a axis expands our understanding of the p53 tumor suppression network in cancer and reveals a novel tumor suppression mechanism involving regulation of specific cancer-relevant microRNAs.
STAR RNA-binding protein Quaking suppresses cancer via stabilization of specific miRNA.
Specimen part, Cell line
View SamplesActivated phosphoinositide 3-kinase (PI3K)-AKT signaling appears to be an obligate event in the development of cancer. The highly related members of the mammalian FoxO transcription factor family, FoxO1, FoxO3, and FoxO4, represent one of several effector arms of PI3K-AKT signaling, prompting genetic analysis of the role of FoxOs in the neoplastic phenotypes linked to PI3K-AKT activation. While germline or somatic deletion of up to five FoxO alleles produced remarkably modest neoplastic phenotypes, broad somatic deletion of all FoxOs engendered a progressive cancer-prone condition characterized by thymic lymphomas and hemangiomas, demonstrating that the mammalian FoxOs are indeed bona fide tumor suppressors. Transcriptome and promoter analyses of differentially affected endothelium identified direct FoxO targets and revealed that FoxO regulation of these targets in vivo is highly context-specific, even in the same cell type. Functional studies validated Sprouty2 and PBX1, among others, as FoxO-regulated mediators of endothelial cell morphogenesis and vascular homeostasis.
FoxOs are lineage-restricted redundant tumor suppressors and regulate endothelial cell homeostasis.
Specimen part
View SamplesIdentify potential QK-regulated mRNAs and linked pathways by comparing the transcriptional profiles of shGFP- and shQK-transduced human Hs683 cells
STAR RNA-binding protein Quaking suppresses cancer via stabilization of specific miRNA.
Cell line
View SamplesIdentify potential QK-regulated mRNAs and linked pathways by comparing the transcriptional profiles of shGFP- and shQK-transduced Ink4a/Arf-/- Pten-/- primary mouse astrocytes
STAR RNA-binding protein Quaking suppresses cancer via stabilization of specific miRNA.
No sample metadata fields
View SamplesIdentify potential miR-20a regulated mRNAs and linked pathways in the setting of QK knockdown by comparing the transcriptional profiles of shQK-transduced human Hs683 cells together with miR-20a or a scrambled miRNA control (miR-NT)
STAR RNA-binding protein Quaking suppresses cancer via stabilization of specific miRNA.
Cell line
View Samples