Rhomboid family protein RHBDF2, an upstream regulator of the epidermal growth factor (EGF) receptor signaling, has been implicated in cutaneous wound healing. However, the underlying molecular mechanisms are still emerging. Using a gain-of-function mutation in the mouse Rhbdf2 gene (Rhbdf2cub/cub), which shows a regenerative phenotype, we sought to identify the underlying mechanism.
Early induction of NRF2 antioxidant pathway by RHBDF2 mediates rapid cutaneous wound healing.
Specimen part, Treatment, Time
View SamplesTyrosine kinase inhibitors (TKI) are highly effective in treatment of chronic myeloid leukemia (CML) but do not eliminate leukemia stem cells (LSC), which remain a potential source of relapse. TKI treatment effectively inhibits BCR-ABL kinase activity in CML LSC, suggesting that additional kinase-independent mechanisms contribute to LSC preservation. We investigated whether signals from the bone marrow (BM) microenvironment protect CML LSC from TKI treatment. Coculture with human BM mesenchymal stromal cells (MSC) significantly inhibited apoptosis and preserved CML stem/progenitor cells following TKI exposure, maintaining colony forming ability and engraftment potential in immunodeficient mice. We found that the N-Cadherin receptor plays an important role in MSC-mediated protection of CML progenitors from TKI. N-Cadherin-mediated adhesion to MSC was associated with increased cytoplasmic N-Cadherin--catenin complex formation, as well as enhanced -catenin nuclear translocation and transcriptional activity. Increased exogenous Wnt-mediated -catenin signaling played an important role in MSC-mediated protection of CML progenitors from TKI treatment. Our results reveal a close interplay between N-Cadherin and the Wnt--catenin pathway in protecting CML LSC during TKI treatment. Importantly, these results reveal novel mechanisms of resistance of CML LSC to TKI treatment, and suggest new targets for treatment designed to eradicate residual LSC in CML patients.
Microenvironmental protection of CML stem and progenitor cells from tyrosine kinase inhibitors through N-cadherin and Wnt-β-catenin signaling.
Specimen part
View SamplesSeveral studies have shown that bone mineral density (BMD), a clinically measurable predictor of osteoporotic fracture, is the sum of genetic and environmental influences. In addition, serum IGF-1 levels have been correlated to both BMD and fracture risk. We previously identified a Quantitative Trait Locus (QTL) for Bone Mineral Density (BMD) on mouse Chromosome (Chr) 6 that overlaps a QTL for serum IGF-1. The B6.C3H-6T (6T) congenic mouse is homozygous for C57BL/6J (B6) alleles across the genome except for a 30 cM region on Chr 6 that is homozygous for C3H/HeJ (C3H) alleles. This mouse was created to study biology behind both the BMD and the serum IGF-1 QTLs and to identify the gene(s) underlying these QTLs. Female 6T mice have lower BMD and lower serum IGF-1 levels at all ages measured. As the liver is the major source of serum IGF-1, we examined differential expression in the livers of fasted female B6 and 6T mice by microarray.
A chromosomal inversion within a quantitative trait locus has a major effect on adipogenesis and osteoblastogenesis.
No sample metadata fields
View SamplesThe recent identification of cancer stem cells (CSCs) in multiple human cancers provides a new inroad to understanding tumorigenesis at the cellular level. CSCs are defined by their characteristics of self-renewal, multipotentiality, and tumor initiation upon transplantation. By testing for these defining characteristics, we provide evidence for the existence of CSCs in a transgenic mouse model of glioma, S100-verbB;Trp53. In this glioma model, CSCs are enriched in the side-population (SP) cells. These SP cells have enhanced tumor-initiating capacity, self-renewal, and multipotentiality compared to non-SP cells from the same tumors. Furthermore, gene expression analysis comparing FACS-sorted cancer SP cells to non-SP cancer cells and normal neural SP cells identified 45 candidate genes that are differentially expressed in glioma stem cells. We validated the expression of two genes from this list (S100a4 and S100a6) in primary mouse gliomas and human glioma samples. Analyses of xenografted human GBM (glioblatoma multiforme) cell lines and primary human glioma tissues show that S100A4 and S100A6 are expressed in a small subset of cancer cells and that their abundance is positively correlated to tumor grade. In conclusion, this study shows that CSCs exist in a mouse glioma model, suggesting that this model can be used to study the molecular and cellular characteristics of CSCs in vivo and to further test the cancer stem cell hypothesis.
Cancer stem cells are enriched in the side population cells in a mouse model of glioma.
No sample metadata fields
View SamplesWe investigated the ability of HDAC inhibitors (HDACi) to target CML stem cells. Treatment with HDACi combined with IM effectively induced apoptosis in quiescent CML progenitors resistant to elimination by IM alone, and eliminated CML stem cells capable of engrafting immunodeficient mice. In vivo administration of HDACi with IM markedly diminished LSC in a transgenic mouse model of CML. The interaction of IM and HDACi inhibited genes regulating hematopoietic stem cell maintenance and survival. HDACi treatment represents a novel and effective strategy to target LSC in CML patients receiving tyrosine kinase inhibitors.
Effective targeting of quiescent chronic myelogenous leukemia stem cells by histone deacetylase inhibitors in combination with imatinib mesylate.
Subject
View SamplesOxidative stress is a harmful condition in a cell, tissue, or organ, caused by an imbalnace between reactive oxygen species and other oxidants and the capacity of antioxidant defense systems to remove them. The budding yeast S. cerevisiae has been the major eukaryotic model for studies of response to oxidative stress.
The genome-wide early temporal response of Saccharomyces cerevisiae to oxidative stress induced by cumene hydroperoxide.
No sample metadata fields
View SamplesCerebral malaria is a severe multifactorial condition associated with the interaction of high numbers of infected erythrocytes to human brain endothelium without invasion into the brain. The result is coma and seizures with death in more than 20% of cases. Because the brain endothelium is at the interface of these processes, we investigated the global gene responses of human brain endothelium after the interaction with Plasmodium falciparuminfected erythrocytes with either high- or low-binding phenotypes. The most significantly up-regulated transcripts were found in gene ontology groups comprising the immune response, apoptosis and antiapoptosis, inflammatory response, cell-cell signaling, and signal transduction and nuclear factor B (NF-B) activation cascade. The proinflammatory NF-B pathway was central to the regulation of the P falciparummodulated endothelium transcriptome. The proinflammatory molecules, for example, CCL20, CXCL1, CXCL2, IL-6, and IL-8, were increased more than 100-fold, suggesting an important role of blood-brain barrier (BBB) endothelium in the innate defense during P falciparuminfected erythrocyte (Pf-IRBC) sequestration. However, some of these diffusible molecules could have reversible effects on brain tissue and thus on neurologic function. The inflammatory pathways were validated by direct measurement of proteins in brain endothelial supernatants. This study delineates the strong inflammatory component of human brain endothelium contributing to cerebral malaria.
Plasmodium falciparum-infected erythrocytes induce NF-kappaB regulated inflammatory pathways in human cerebral endothelium.
No sample metadata fields
View SamplesFrom our previous data, we found that loss of ATAD3A gene expression in breast cancer cells results in loss of cell motility in vitro and metastasis in vivo. To obtain a better understanding of oncogenic pathway of ATAD3A, we have established the stable ATAD3A knockdown MDA-MB-231 cells using lentiviral strategy.
Mitochondrial ATAD3A combines with GRP78 to regulate the WASF3 metastasis-promoting protein.
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
An epigenetic mechanism of resistance to targeted therapy in T cell acute lymphoblastic leukemia.
Specimen part, Cell line
View SamplesHere we modeled T-ALL resistance to Notch inhibition, identifying persister cells that readily expand in the presence of gamma secretase inhibitor (GSI) and the absence of Notch signaling. Rare persister cells are already present in nave T-ALL populations, and the reversibility of the phenotype is suggestive of an epigenetic mechanism. Relative to GSI-sensitive cells, persisters activate distinct signaling and gene expression programs, and exhibit global chromatin compaction. A shRNA screen identified chromatin regulators whose depletion preferentially impairs persister cell viability, including BRD4, an acetyl-histone reader. BRD4 is up-regulated in the persisters and binds enhancers near genes with critical functions in T-ALL, including MYC and BCL2. Treatment of persisters with the BRD4 inhibitor JQ1 down-regulates these targets and induces growth arrest and apoptosis, at doses well tolerated by GSI-sensitive cells. Prompted by these findings, we examined and established the efficacy of GSI JQ1 combination therapy against primary human leukemias in vivo. Our findings establish a role for epigenetic heterogeneity in leukemia drug resistance and suggest the potential of combination therapies that include epigenetic modulators to prevent and treat resistant disease.
An epigenetic mechanism of resistance to targeted therapy in T cell acute lymphoblastic leukemia.
Specimen part, Cell line
View Samples