Neurofibromatosis Type 1 (NF1) patients develop benign neurofibromas and malignant peripheral nerve sheath tumors (MPNST). These incurable peripheral nerve tumors result from loss of NF1 tumor suppressor gene function, causing hyperactive Ras signaling. Activated Ras controls numerous downstream effectors, but specific pathways mediating effects of hyperactive Ras in NF1 tumors are unknown. Cross-species transcriptome analyses of mouse and human neurofibromas and MPNSTs identified global negative feedback of genes that regulate Ras-Raf- MEK- extracellular signal-regulated protein kinase (ERK) signaling in both species. Nonetheless, activation of ERK was sustained in mouse and human neurofibromas and MPNST. PD0325901, a highly selective pharmacological inhibitor of MEK, was used to test whether sustained Ras-Raf-MEK-ERK signaling contributes to neurofibroma growth in the Nf1fl/fl;Dhh-cre mouse model or in NF1 patient MPNST cell xenografts. PD0325901 treatment reduced aberrantly proliferating cells in neurofibroma and MPNST, prolonged survival of mice implanted with human MPNST cells, and shrank neurofibromas in >80% of mice tested. PD0325901 also caused effects on tumor vasculature. Our data demonstrate that deregulated Ras/ERK signaling is critical for the growth of NF1 peripheral nerve tumors and provide strong rationale for testing MEK inhibitors in NF1 clinical trials.
MEK inhibition exhibits efficacy in human and mouse neurofibromatosis tumors.
Specimen part
View SamplesThe feather follicle is a “professional” regenerative organ that undergoes natural cycling and, regeneration after wound plucking. Similar to mammalian hair follicle, dermal papilla (DP) controls feather regeneration, shape, size, and axis. Here we report gene expression profiling for feather DP at different growth stages. For growth phase, we compared gene expression of DP, the ramogenic zone of feather branching epithelium (Erz) and the mesenchymal pulp (Pp). We also compared gene expression of DP at resting phase. To characterize the feather regeneration process, we further profiled gene expression at Day-2 and Day-4 post wound. Our results provide a resource for investigating feather growth and regeneration. Overall design: Examination of gene expression in dermal papilla (DP) at growth phase and resting phase feather follicle, and during feather regeneration.
Dkk2/Frzb in the dermal papillae regulates feather regeneration.
Specimen part, Subject
View SamplesThe epithelial-mesenchymal transition (EMT) is a multistep dedifferentiation program important in tissue repair. Here, we examined the role of the transcriptional regulator NFkB in EMT of human primary small airway epithelial cells (hSAECs). Surprisingly, transforming growth factor ß (TGFß) activated NFkB/RELA proto-oncogene, NFkB subunit (RELA) translocation within 1 day of stimulation, yet induction of its downstream gene regulatory network occurred only after 3 days. A time course of TGFß-induced EMT transition was analyzed by RNA-Seq in the absence or presence of inducible shRNA-mediated silencing of RELA. In WT cells, TGFß stimulation significantly affected the expression of 2,441 genes. Gene set enrichment analysis identified Wnt, cadherin, and NFkB signaling as the most prominent TGFß-inducible pathways. By comparison, RELA controlled expression of 3,138 overlapping genes mapping to Wnt, cadherin, and chemokine signaling pathways. Conducting upstream regulator analysis, we found that RELA controls six clusters of upstream transcription factors, many of which overlapped with a transcription factor topology map of EMT developed earlier. RELA triggered expression of three key EMT pathways: (1) the Wnt/ß-catenin morphogen pathway, (2) the JUN transcription factor, and (3) the Snail family transcriptional repressor 1 (SNAI1). RELA binding to target genes was confirmed by ChIP. Experiments independently validating Wnt dependence on RELA were performed by silencing RELA via genome editing and indicated that TGFß-induced WNT5B expression and downstream activation of the Wnt target AXIN2 are RELA-dependent. We conclude that RELA is a master transcriptional regulator of EMT upstream of Wnt morphogen, JUN, SNAI1-ZEB1, and interleukin-6 autocrine loops. Overall design: RNA-seq transcriptome profiling of TGF-Beta stimulated RelA wildtype and knock-down cells
The NFκB subunit RELA is a master transcriptional regulator of the committed epithelial-mesenchymal transition in airway epithelial cells.
Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Alternative generation of CNS neural stem cells and PNS derivatives from neural crest-derived peripheral stem cells.
Specimen part
View SamplesNeural crest-derived neural stem cells (NCSCs) from the embryonic PNS can be reprogrammed in neurosphere culture (NS) to rNCSCs that produce CNS progeny, including myelinating oligodendrocytes. Using global gene expression analysis we now demonstrate that rNCSCs completely lose their previous PNS characteristics and acquire the identity of neural stem cells derived from embryonic spinal cord (SCSCs). Reprogramming proceeds rapidly and results in a homogenous population of Olig2-, Sox3- and Lex-positive CNS stem cells. Low-level expression of pluripotency inducing genes Oct4, Nanog and Klf4 argues against a transient pluripotent state during reprogramming. The acquisition of CNS properties is prevented in the presence of BMP4 (BMP NCSCs) as shown by marker gene expression and the potential to produce PNS neurons and glia. In addition, genes characteristic for mesenchymal and perivascular progenitors are expressed, which suggests that BMP NCSCs are directed towards a pericyte progenitor/mesenchymal stem cell (MSC) fate. Adult NCSCs from mouse palate, an easily accessible source of adult NCSCs, display strikingly similar properties. They do not generate cells with CNS characteristics but lose the neural crest markers Sox10 and p75 and produce MSCs. These findings show that embryonic NCSCs acquire a full CNS identity in neurosphere culture. In contrast, MSCs are generated from adult pNCSCs and BMP NCSCs, which reveals that postmigratory NCSCs are a source for MSCs up to the adult stage.
Alternative generation of CNS neural stem cells and PNS derivatives from neural crest-derived peripheral stem cells.
Specimen part
View SamplesNeural crest-derived neural stem cells (NCSCs) from the embryonic PNS can be reprogrammed in neurosphere culture (NS) to rNCSCs that produce CNS progeny, including myelinating oligodendrocytes. Using global gene expression analysis we now demonstrate that rNCSCs completely lose their previous PNS characteristics and acquire the identity of neural stem cells derived from embryonic spinal cord (SCSCs). Reprogramming proceeds rapidly and results in a homogenous population of Olig2-, Sox3- and Lex-positive CNS stem cells. Low-level expression of pluripotency inducing genes Oct4, Nanog and Klf4 argues against a transient pluripotent state during reprogramming. The acquisition of CNS properties is prevented in the presence of BMP4 (BMP NCSCs) as shown by marker gene expression and the potential to produce PNS neurons and glia. In addition, genes characteristic for mesenchymal and perivascular progenitors are expressed, which suggests that BMP NCSCs are directed towards a pericyte progenitor/mesenchymal stem cell (MSC) fate. Adult NCSCs from mouse palate, an easily accessible source of adult NCSCs, display strikingly similar properties. They do not generate cells with CNS characteristics but lose the neural crest markers Sox10 and p75 and produce MSCs. These findings show that embryonic NCSCs acquire a full CNS identity in neurosphere culture. In contrast, MSCs are generated from adult pNCSCs and BMP NCSCs, which reveals that postmigratory NCSCs are a source for MSCs up to the adult stage.
Alternative generation of CNS neural stem cells and PNS derivatives from neural crest-derived peripheral stem cells.
Specimen part
View SamplesThe airway epithelial cell plays a central role in coordinating pulmonary response to injury and inflammation. Here, transforming growth factor-b (TGFb) activates gene expression programs to induce stem cell-like properties, inhibit expression of differentiated epithelial adhesion proteins and express mesenchymal contractile proteins. This process is known as epithelial mesenchymal transition (EMT); although much is known about the role of EMT in cellular metastasis in an oncogene-transformed cell, less is known about Type II EMT, that occurring in normal epithelial cells. In this study, we applied next generation sequencing (RNA-seq) in primary human airway epithelial cells to understand the gene program controlling Type II EMT and how cytokine-induced inflammation modifies it. Generalized linear modeling was performed on a two-factor RNA-seq experiment of 6 treatments of telomerase immortalized human small airway epithelial cells (3 replicates). Using a stringent cut-off, we identified 3,478 differentially expressed genes (DEGs) in response to EMT. Unbiased transcription factor enrichment analysis identified three clusters of EMT regulators, one including SMADs/TP63 and another NF-kB/RelA. Surprisingly, we also observed 527 of the EMT DEGs were also regulated by the TNF-NF-kB/RelA pathway. This Type II EMT program was compared to Type III EMT in TGFb stimulated A549 alveolar lung cancer cells, revealing significant functional differences. Moreover, we observe that Type II EMT modifies the outcome of the TNF program, reducing IFN signaling and enhancing integrin signaling. We confirmed experimentally that TGFb-induced the NF-kB/RelA pathway by observing a 2-fold change in NF-kB/RelA nuclear translocation. A small molecule IKK inhibitor blocked TGFb-induced core transcription factor (SNAIL1, ZEB1 and Twist1) and mesenchymal gene (FN1 and VIM) expression. These data indicate that NF-kB/RelA controls a SMAD-independent gene network whose regulation is required for initiation of Type II EMT. Type II EMT dramatically affects the induction and kinetics of TNF-dependent gene networks. Overall design: A human small airway epithelial cell line was treated with TGF-Beta to induce the epithelial to mesenchymal transition. TGF-Beta treated and untreated cells were further treated with TNF-alpha for 1 and 12 hours. Three replicates for each treatment and untreated controls were performed for a total of 18 samples.
Analysis of the TGFβ-induced program in primary airway epithelial cells shows essential role of NF-κB/RelA signaling network in type II epithelial mesenchymal transition.
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View SamplesExtracellular, cancer-specific methylated DNA has been shown to be a prognostic marker when detected in serum or plasma. In this study we investigated the effect of treating cancer cells with differentially methylated CpG DNA. When breast cancer cell lines were treated with methylated CpG DNA, a consistent upregulation of CHAC1 mRNA expression was observed. CHAC1 was recently described to be a novel component of the unfolded protein response pathway. To elucidate the role of CHAC1 mRNA expression in cancer in more detail, we analyzed expression of this gene in breast (n=107) and ovarian cancer (n=107) and found a strong correlation with tumor differentiation. Poorly differentiated tumors exhibited higher CHAC1 expression levels (p=0.004 for breast and p=0.031 for ovarian cancer). Additionally, hormone receptor (HR)-negative breast cancers (p<0.001) and advanced stage disease ovarian cancers (p=0.026) also demonstrated high CHAC1 mRNA levels. mRNA expression analysis of the two known CHAC1 isoforms showed a strong association of expression above the median with poor outcome in breast cancer patients in a multivariate analysis (isoform a: relative risk (RR) of death 3.2 (95% CI 1.6-6.5; p<0.01); RR of relapse 3.9 (95% CI 1.6-9.8; p<0.01); isoform b: relative risk (RR) of death 3.5 (95% CI 1.6-7.3; p<0.01); RR of relapse 6.6 (95% CI 2.4-18.5; p<0.01)). Univariate analysis in ovarian cancer showed that CHAC1 mRNA expression above the median was associated with a poor relapse free survival (p=0.03). In younger ovarian cancer patients (age < median age), a high CHAC1 mRNA expression was associated with overall survival (p=0.007) and relapse free survival (p=0.015). Finally, we show that downregulation of CHAC1 by small interfering RNA suppressed breast cancer cell migration and proliferation, whereas overexpression resulted in an observed increase in these cellular behaviours. This is the first report demonstrating that a gene (CHAC1) whose expression is triggered by methylated, but not unmethylated DNA, is involved in tumour biology.
Elevated mRNA expression of CHAC1 splicing variants is associated with poor outcome for breast and ovarian cancer patients.
Specimen part, Cell line, Treatment
View SamplesThis series analyses germinating Arabidopsis seeds with both temporal and spatial detail, revealing two transcriptional phases that are separated with respect to testa rupture. Performed as part of the ERA-NET Plant Genomics grant vSEED.
Transcriptional dynamics of two seed compartments with opposing roles in Arabidopsis seed germination.
Specimen part, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The lncRNA HOTAIR impacts on mesenchymal stem cells via triple helix formation.
Specimen part, Treatment
View Samples