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 etiology of autoimmune hepatitis is poorly understood but likely involves Th1 cells producing IFN-. BALB/c background TGF-1-/- mice rapidly develop fulminant Th1-mediated autoimmune hepatitis. Our aims are to profile liver gene expression in TGF-1-/- mice, to identify gene expression pathways dependent on IFN- as possible targets for rational therapy, and to test potential targets directly in vivo in mice.
The role of Ifng in alterations in liver gene expression in a mouse model of fulminant autoimmune hepatitis.
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View SamplesTumors engender an environment dominated by M2 differentiated tumor macrophages that support tumor invasion, metastases and escape from immune control. In this study, we demonstrate that following radiation therapy of tumors in mice there is an influx of tumor macrophages that polarize towards wound repair and immune suppression.
Expression of NF-κB p50 in tumor stroma limits the control of tumors by radiation therapy.
Specimen part, Treatment, Time
View SamplesThe capacity of the hematopoietic system to promptly respond to peripheral demands relies on adequate pools of progenitors able to transiently proliferate and differentiate in a regulated manner. However, little is known about factors that may restrain progenitor maturation to maintain their reservoirs. In addition to a profound defect in hematopoietic stem cell (HSC) self-renewal, conditional knockout mice for the Pbx1 proto-oncogene have a significant reduction in lineage-restricted progenitors, including common myeloid progenitors (CMPs) and, to a lesser extent, granulocyte-monocyte progenitors (GMPs).
Pbx1 restrains myeloid maturation while preserving lymphoid potential in hematopoietic progenitors.
Age, Specimen part
View SamplesG1ME cells are GATA1-deficient murine bipotential megakaryocyte/erythrocyte progenitor cells derived from Gata1-negative murine ES cells. In order to assess the impact of GATA1 on gene regulation and cell differentiation, an expression construct was used to transiently produce high levels of GATA1. Cells transduced with this construct or a vector control were harvested at 18 and 42 hours, and gene expression was analyzed using Affymetrix MOE430 version 2 arrays.
Graded repression of PU.1/Sfpi1 gene transcription by GATA factors regulates hematopoietic cell fate.
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The role of hypoxia in 2-butoxyethanol-induced hemangiosarcoma.
Specimen part, Treatment, Time
View SamplesMice were treated with either 100mg/kg baclofen or 0.5% methylcellulose alone by oral gavage for 1 or 5 days.
The role of hypoxia in 2-butoxyethanol-induced hemangiosarcoma.
Specimen part, Treatment, Time
View SamplesMice were dosed with 2-BE (900mg/kg) or vehicle by oral gavage and sacrificied either after 4 hours of a single dose or after 7 days of daily dosing.
The role of hypoxia in 2-butoxyethanol-induced hemangiosarcoma.
Specimen part, Treatment, Time
View Samples