Ewings sarcoma is highly malignant bone tumor that involves childhood and adolescent, and its nature has not been well understood. To clarify its cellular origin and the mechanisms of tumorigenesis, we used ex vivo approach to create a murine model for Ewings sarcoma. The osteochondrogenic progenitors derived from the embryonic superficial zone (eSZ, designated as FZ in the data set) of murine long bones at late gestation were purified by microdissection, introduced with EWS-FLI1 or EWS-ERG retroviruses and transplanted into nude mice. Ewings sarcoma-like small round cell sarcoma developed at 100% penetrance, whereas tumor induction was less effective when growth place (GP)-derived cells were used. The different response of gene expression to EWS-FLI1 between eSZ and GP cells suggests importance of the specific cellular context for EWS-FLI1 to induce Ewings sarcoma. The Wnt/-catenin pathway was involved in close relationship to the cellular context, with Dkk2 and Wipf1 as important downstream modulators. Furthermore, gene expression profiling revealed similarity between our models and human Ewings sarcoma. These results indicate that Ewings sarcoma originates from the embryonic osteochondrogenic progenitor.
Ewing's sarcoma precursors are highly enriched in embryonic osteochondrogenic progenitors.
Specimen part, Time
View SamplesEwings sarcoma is highly malignant bone tumor that involves childhood and adolescent, and its nature has not been well understood. To clarify its cellular origin and the mechanisms of tumorigenesis, we used ex vivo approach to create a murine model for Ewings sarcoma. The osteochondrogenic progenitors derived from the facial zone (FZ) of murine long bones at late gestation were purified by microdissection, introduced with EWS-FLI1 or EWS-ERG retroviruses and transplanted into nude mice. Ewings sarcoma-like small round cell sarcoma developed at 100% penetrance, whereas tumor induction was less effective when growth place (GP)-derived cells were used. The different response of gene expression to EWS-FLI1 between FZ and GP cells suggests importance of the specific cellular context for EWS-FLI1 to induce Ewings sarcoma. The Wnt/-catenin pathway was involved in close relationship to the cellular context, with Dkk2 and Wipf1 as important downstream modulators. Furthermore, gene expression profiling revealed similarity between our models and human Ewings sarcoma. These results indicate that Ewings sarcoma originates from the embryonic osteochondrogenic progenitor.
Ewing's sarcoma precursors are highly enriched in embryonic osteochondrogenic progenitors.
Specimen part
View SamplesPercellome analysis of whole Xenopus embryos at developmental stage 18
Active repression by RARγ signaling is required for vertebrate axial elongation.
Specimen part
View SamplesDuring development of the mammalian central nervous system (CNS), neurons and glial cells (astrocytes and oligodendrocytes) are generated from common neural precursor cells (NPCs). However, neurogenesis precedes gliogenesis, which normally commences at later stages of fetal telencephalic development. Astrocyte differentiation of mouse NPCs at embryonic day (E) 14.5 (relatively late gestation) is induced by activation of the transcription factor STAT3, whereas at E11.5 (mid-gestation) NPCs do not differentiate into astrocytes even when stimulated by STAT3-activating cytokines such as leukemia inhibitory factor (LIF). This can be explained in part by the fact that astrocyte-specific gene promoters are highly methylated in NPCs at E11.5, but other mechanisms are also likely to play a role. We therefore sought to identify genes involved in the inhibition of astrocyte differentiation of NPCs at midgestation. We first examined gene expression profiles in E11.5 and E14.5 NPCs, using Affymetrix GeneChip analysis, applying the Percellome method to normalize gene expression level. We then conducted in situ hybridization analysis for selected genes found to be highly expressed in NPCs at midgestation. Among these genes, we found that N-myc and high mobility group AT-hook 2 (Hmga2) were highly expressed in the E11.5 but not the E14.5 ventricular zone of mouse brain, where NPCs reside. Transduction of N-myc and Hmga2 by retroviruses into E14.5 NPCs, which normally differentiate into astrocytes in response to LIF, resulted in suppression of astrocyte differentiation. However, sustained expression of N-myc and Hmga2 in E11.5 NPCs failed to maintain the hypermethylated status of an astrocyte-specific gene promoter. Taken together, our data suggest that astrocyte differentiation of NPCs is regulated not only by DNA methylation but also by genes whose expression is controlled spatio-temporally during brain development.
Identification of genes that restrict astrocyte differentiation of midgestational neural precursor cells.
No sample metadata fields
View SamplesBisphenol A (BPA), an endocrine-disrupting chemical (EDC), is a well-known, ubiquitous estrogenic chemical. To investigate the effects of fetal exposure to low-dose BPA on the development of the prostate, we first examined the alterations of in situ sex steroid hormonal environment in the mouse urogenital sinus (UGS).
Endocrine disrupter bisphenol A increases in situ estrogen production in the mouse urogenital sinus.
Specimen part
View SamplesNeuroblastoma is a pediatric tumor of the sympathetic nervous system. MYCN (V-myc myelocytomatosis viral-related oncogene, neuroblastoma derived [avian]) is amplified in 20% of neuroblastomas, and these tumors carry a poor prognosis. However, tumors without MYCN amplification also may have a poor outcome. Here, we identified downstream targets of MYCN by shRNA-mediated silencing MYCN in neuroblastoma cells. From these targets, 157 genes showed an expression profile correlating with MYCN mRNA levels in NB88, a series of 88 neuroblastoma tumors, and therefore represent in vivo relevant MYCN pathway genes. This 157-gene signature identified very poor prognosis tumors in NB88 and independent neuroblastoma cohorts and was more powerful than MYCN amplification or MYCN expression alone. Remarkably, this signature also identified poor outcome of a group of tumors without MYCN amplification. Most of these tumors have low MYCN mRNA levels but high nuclear MYCN protein levels, suggesting stabilization of MYCN at the protein level. One tumor has an MYC amplification and high MYC expression. Chip-on-chip analyses showed that most genes in this signature are directly regulated by MYCN. MYCN induces genes functioning in cell cycle and DNA repair while repressing neuronal differentiation genes. The functional MYCN-157 signature recognizes classical neuroblastoma with MYCN amplification, as well as a newly identified group marked by MYCN protein stabilization.
Functional MYCN signature predicts outcome of neuroblastoma irrespective of MYCN amplification.
Specimen part, Cell line, Time
View SamplesThe targeting of oncogenic ‘driver’ kinases with small molecule inhibitors has proven to be a highly effective therapeutic strategy in selected non-small cell lung cancer (NSCLC) patients. However, acquired resistance to targeted therapies invariably arises and is a major limitation to patient care. ROS1 fusion proteins are a recently described class of oncogenic driver, and NSCLC patients that express these fusions generally respond well to ROS1-targeted therapy. In this study, we sought to determine mechanisms of acquired resistance to ROS1 inhibition. To accomplish this, we generated a ROS1 inhibition-resistant derivative of the initially sensitive NSCLC cell line HCC78.
Resistance to ROS1 inhibition mediated by EGFR pathway activation in non-small cell lung cancer.
No sample metadata fields
View SamplesRigosertib treatment of head and neck squamous cell cancer
The dual pathway inhibitor rigosertib is effective in direct patient tumor xenografts of head and neck squamous cell carcinomas.
Specimen part, Cell line
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