Adult neurogenesis occurs in mammals and provides a mechanism for continuous neural plasticity in the brain.However, little is known about the molecular mechanisms regulating hippocampal neural progenitor cells (NPCs) and whether their fate can be pharmacologically modulated to improve neural plasticity and regeneration. Here, we report the characterization of a unique small molecule (KHS101) that selectively induces a neuronal differentiation phenotype. Mechanism of action studies revealed a link of KHS101 to cell cycle exit and specific binding to the TACC3 protein, whose knockdown in NPCs recapitulates the KHS101-induced phenotype. Upon systemic administration, KHS101 distributed to the brainandresulted in a significant increase in neuronal differentiation in vivo. Our findings indicate that KHS101 accelerates neuronal differentiation by interaction with TACC3 and may provide a basis for pharmacological intervention.directed at endogenous NPCs.
A small molecule accelerates neuronal differentiation in the adult rat.
Specimen part, Treatment
View SamplesNeuregulin (NRG) signaling through the receptor tyrosine kinase, ERBB3, is required for embryonic development, and dysregulated signaling has been associated with cancer progression. Here, we show that NRG1/ERBB3 signaling inhibits melanocyte (MC) maturation and promotes undifferentiated, migratory and proliferative cellular characteristics. Embryonic analyses demonstrated that initial MC specification and distribution were not dependent on ERBB3 signaling. However NRG1/ERBB3 signaling was both necessary and sufficient to inhibit differentiation of later stages of MC development in culture. Analysis of tissue arrays of human melanoma samples suggests that ERBB3 signaling may also contribute to metastatic progression of melanoma as ERBB3 was phosphorylated in primary tumors compared with nevi or metastatic lesions. Neuregulin 1-treated MCs demonstrated increased proliferation and invasion and altered morphology concomitant with decreased levels of differentiation genes, increased levels of proliferation genes and altered levels of melanoma progression and metastases genes. ERBB3 activation in primary melanomas suggests that NRG1/ERBB3 signaling may contribute to the progression of melanoma from benign nevi to malignancies. We propose that targeting ERBB3 activation and downstream genes identified in this study may provide novel therapeutic interventions for malignant melanoma.
NRG1 / ERBB3 signaling in melanocyte development and melanoma: inhibition of differentiation and promotion of proliferation.
Specimen part
View SamplesMitochondria control bioenergetics and cell fate decisions, but whether they also participate in extra-organelle signaling is not understood. Here, we show that interference with cyclophilin D (CypD), a mitochondrial matrix protein and apoptosis regulator, causes accelerated cell proliferation and enhanced cell migration and invasion. These responses are associated with global transcriptional changes in CypD-/- cells, predominantly affecting chemokines and their receptors, and resulting in increased activating phosphorylation of Signal Transduction and Activator of Transcription 3 (STAT3). In turn, STAT3 signaling promotes increased proliferation of CypD-/- cells via accelerated S-phase entry and supports Cxcl12-directed paracrine cell motility. Therefore, mitochondria-to-nuclei transcriptional signaling globally affects cell division and motility. As immunosuppressive therapies often target CypD, this pathway may predispose the tissue microenvironment of these patients to oncogenic transformation.
Cyclophilin D extramitochondrial signaling controls cell cycle progression and chemokine-directed cell motility.
Specimen part
View SamplesWe have combined large-scale mRNA expression and gene mapping methods to identify genes and loci that control hematopoietic stem cell (HSC) functioning. mRNA expression levels were measured in purified HSC isolated from a panel of densely genotyped recombinant inbred mouse strains. Quantitative trait loci (QTLs) associated with variation in expression of thousands of transcripts were mapped. Comparison of the physical transcript position with the location of the controlling QTL identified polymorphic cis-acting stem cell genes. In addition, multiple trans-acting control loci were highlighted that modify expression of large numbers of genes. These groups of co-regulated transcripts identify pathways that specify variation in stem cells. We illustrate this concept with the identification of strong candidate genes involved with HSC turnover. We compared expression QTLs in HSC and brain from the same animals, and document both shared and tissue-specific QTLs. Our data are accessible through WebQTL, a web-based interface that allows custom genetic linkage analysis and identification of co-regulated transcripts.
Uncovering regulatory pathways that affect hematopoietic stem cell function using 'genetical genomics'.
No sample metadata fields
View SamplesDU145 prostate cancer cells were treated with 25 ng/ml hepatocyte growth factor (HGF) or vehicle for 2, 8, or 24 hours. HGF stimulates the cMET protein, a tyrosine kinase transmembrane protein.
Activation of c-MET induces a stem-like phenotype in human prostate cancer.
Cell line, Time
View SamplesTo gain more insight into initiation and regulation of T cell receptor (TCR) gene rearrangement during human T cell development, we analyzed TCR gene rearrangements by quantitative PCR analysis in nine consecutive T-cell developmental stages, including CD34+ lin- cord blood cells as a reference. The same stages were used for gene expression profiling using DNA microarrays.
New insights on human T cell development by quantitative T cell receptor gene rearrangement studies and gene expression profiling.
Specimen part
View SamplesT cells develop from progenitors that migrate from the bone marrow into the thymus. Thymocytes are subdivided roughly as being double negative (DN), double positive (DP), or single positive (SP), based on the expression of the CD4 and CD8 coreceptors. The DN stage is heterogeneous and can be subdivided into four distinct subsets in mice based on the expression of CD44 and CD25. In human, three distinct DN stages can be recognized: a CD34+CD38CD1a stage that represents the most immature thymic subset and the consecutive CD34+CD38+CD1a and CD34+CD38+CD1a+ stages. Human DN thymocytes mature via an immature single positive (ISP CD4+) and a DP stage into CD4+ or CD8+ SP T cells that express functional T cell receptors (TCR) and that exit the thymus. In this study, gene expression was measured in each of these nine stages.
New insights on human T cell development by quantitative T cell receptor gene rearrangement studies and gene expression profiling.
No sample metadata fields
View SamplesBreast cancer metastasis to bone is a critical determinant of long-term survival after treatment of primary tumors. We used a mouse model of spontaneous bone metastasis to determine new molecular mechanisms. Differential transcriptome comparisons of primary and metastatic tumor cells revealed that a substantial set of genes suppressed in bone metastases were highly enriched for promoter elements for the type I interferon (IFN) regulatory factor, Irf7, itself suppressed in mouse and human metastases. The critical function of the Irf7 pathway was demonstrated by restoration of exogenous Irf7 or systemic interferon administration, which significantly reduced bone metastases and prolonged metastasis-free survival. Using mice deficient in the type I receptor (Ifnar1-/-) or mature B, T and NK cell responses (NOD Scid IL-2r-/- mice), we demonstrated that Irf7-driven suppression of metastasis was reliant on IFN signaling to host immune cells. Metastasis suppression correlated with decreased accumulation of myeloid-derived suppressor cells and increased CD4++, CD8 T cells and NK cells in the peripheral blood and was reversed by depletion of CD8+ cells and NK cells. Clinical importance of our findings was demonstrated as increased primary tumor Irf7 expression predicted prolonged bone and lung metastasis-free survival. Thus we report for the first time, a novel innate immune pathway, intrinsic to breast cancer cells, whose suppression in turn restricts systemic immunosurveillance to enable metastasis. This pathway may constitute a novel therapeutic target for restricting breast cancer metastases.
Silencing of Irf7 pathways in breast cancer cells promotes bone metastasis through immune escape.
Specimen part
View SamplesTargeting components of the mitogen-activated protein kinase (MAPK) pathway prolongs survival of patients with advanced BRAFV600E melanomas but such an approach is not curative because of the rapid acquisition of numerous resistance mechanisms. Here we analyze melanoma cells that evade MAPK inhibitors by undergoing a senescence-like, slow-growth, phenotype, which leads to acquired resistance. The initial therapeutic response is characterized by an integrated stress response program, including stimulation of autophagic flux, activation of the endoplasmic reticulum machinery, and an enhanced ability of detoxifying reactive oxygen species. Reversibly senescent cells also exhibit an increase in mitochondrial genome copy number and a strong metabolic shift towards oxidative phosphorylation (OxPhos). Inducing mitochondrial dysfunction by co-targeting the MAPK pathway and mitochondrial Hsp90-directed protein folding with specific inhibitors prevented entry of cells into a reversibly senescent state, suppressed mitochondrial energy metabolism and augmented therapy response.
Targeting mitochondrial biogenesis to overcome drug resistance to MAPK inhibitors.
Disease, Disease stage, Cell line, Time
View SamplesCHEK2 1100delC is a moderate-risk cancer susceptibility allele that confers a high breast cancer risk in a polygenic setting. Gene expression profiling of CHEK2 1100delC breast cancers may reveal clues to the nature of the polygenic CHEK2 model and its genes involved. Here, we report global gene expression profiles of a cohort of 155 familial breast cancers, including 26 CHEK2 1100delC mutant tumors. A 40-gene CHEK2 signature was defined that significantly associated with CHEK2 1100delC breast cancers. The identification of a CHEK2 gene signature implies an unexpected biological homogeneity among the CHEK2 1100delC breast cancers. In addition, all 26 CHEK2 1100delC tumors classified as luminal intrinsic subtype breast cancers, with 8 luminal A and 18 luminal B tumors. This biological make-up of CHEK2 1100delC breast cancers suggests that a relatively limited number of additional susceptibility alleles are involved in the polygenic CHEK2 model. Identification of these as-yet-unknown susceptibility alleles should be aided by clues from the 40-gene CHEK2 signature.
Gene expression profiling assigns CHEK2 1100delC breast cancers to the luminal intrinsic subtypes.
Specimen part
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