Mutations in the PTEN, TP53 and RB1 pathways are obligate events in the pathogenesis of human glioblastomas, the highest grade of astrocytoma. To investigate synergy between these tumor suppressors in mice, we induced various combinations of compound deletions conditionally in astrocytes and neural precursors in the mature brain. The resulting highly penetrant astrocytomas showed a spectrum of histopathological variation reminiscent of human tumors, and ranged from grade III to grade IV (glioblastoma). Secondary somatic mutations varied depending on the combination of initiating deletions and were relevant to human disease. Receptor tyrosine kinase amplifications were frequent in tumors initiated by combined conditional deletion of Pten and Tp53, but not when Rb, Pten and Tp53 were simultaneously deleted. Multiple mutations within PI3K and Rb pathways were acquired, however, Mapk activation was not consistently detected in astrocytomas. Gene expression profiling revealed striking similarities to previously described human astrocytoma subclasses. A subset of astrocytomas initiated outside of proliferative niches in the adult brain.
Cooperativity within and among Pten, p53, and Rb pathways induces high-grade astrocytoma in adult brain.
Sex, Specimen part
View SamplesPurpose: More than 90% of children with diffuse intrinsic pontine glioma (DIPG) die within 2 years of diagnosis. There is a dire need to identify therapeutic targets, however lack of patient material for research has limited progress. We evaluated a large cohort of diffuse intrinsic pontine gliomas (DIPGs) to identify recurrent genomic abnormalities and gene expression signatures underlying DIPG.
Genome-wide analyses identify recurrent amplifications of receptor tyrosine kinases and cell-cycle regulatory genes in diffuse intrinsic pontine glioma.
Age, Specimen part, Disease
View SamplesPurpose: To define copy number alterations and gene expression signatures underlying pediatric high-grade glioma (HGG). Patients and Methods: We conducted a high-resolution analysis of genomic imbalances in 78 de novo pediatric HGG, including 7 diffuse intrinsic pontine gliomas, and 10 HGG cases arising in children who received cranial irradiation for a previous cancer, using Affymetrix 500K GeneChips. Gene expression signatures for 53 tumors were analyzed with Affymetrix U133v2 arrays. Results were compared with publicly available data from adult tumors. Results: Pediatric and adult glioblastoma were clearly distinguished by frequent gain of chromosome 1q (30% vs 9%) and lower frequency of chromosome 7 gain (13% vs 74%), respectively. The most common focal amplifications also differed, with PDGFRA and EGFR predominant in childhood and adult populations respectively. These common alterations in pediatric HGG were detected at higher frequency in irradiation-induced tumors, suggesting that these are initiating events in childhood gliomagenesis. CDKN2A was the most common tumor suppressor gene targeted by homozygous deletion in pediatric HGG. No IDH1 hotspot mutations were found in pediatric tumors, highlighting molecular differences in pathogenesis between childhood HGG and adult secondary glioblastoma. Integrated copy number and gene expression data indicated that deregulated PDGFRA signaling plays a major role in pediatric HGG. Conclusions: Integrated molecular profiling showed substantial differences in the molecular features underlying pediatric and adult HGG, indicating that findings in adult tumors cannot be simply extrapolated to younger patients. PDGFRA may be a useful target for pediatric HGG including diffuse pontine gliomas.
Integrated molecular genetic profiling of pediatric high-grade gliomas reveals key differences with the adult disease.
Age, Disease
View SamplesGlioblastoma multiforme (GBM) is an aggressive primary brain cancer that includes focal amplification of PDGFR and for which there are no effective therapies. Herein, we report the development of a genetically engineered mouse model of GBM based on autocrine, chronic stimulation of PDGFR and the analysis of GBM signaling pathways using proteomics. We discovered the tubulin-binding protein Stathmin1 (STMN1) as a PDGFR phospho-regulated target and that this mis-regulation conferred selective sensitivity to vinblastine (VB) cytotoxicity. Treatment of PDGFR GBMs with VB in mice drastically prolonged survival and was dependent on STMN1. Our work provides a rationale for evaluating genotype-specific anti-microtubule drugs as cancer treatment in select GBM patient populations.
A PDGFRα-driven mouse model of glioblastoma reveals a stathmin1-mediated mechanism of sensitivity to vinblastine.
Specimen part, Treatment
View SamplesFew studies have investigated heterogeneity of selection response in replicate lines subjected to equivalent selection. We developed 4 replicate lines of mice based on high levels of voluntary wheel running (high runner or HR lines) while also maintaining 4 non-selected control lines. This led to the unexpected discovery of the HR mini-muscle (HRmini) phenotype, recognized by a 50% reduction in hindlimb muscle mass, which became fixed in 1 of the 4 HR selected lines.
Gene expression profiling of gastrocnemius of "minimuscle" mice.
Sex, Specimen part
View SamplesAnalysis of estrogen receptor (ER)-positive MCF7 cell total RNA expression and polysome-assiciated RNA expression following treatment with estradiol (E2) and vehicle (etoh).
Estrogen coordinates translation and transcription, revealing a role for NRSF in human breast cancer cells.
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Induced p53 loss in mouse luminal cells causes clonal expansion and development of mammary tumours.
Sex, Specimen part
View SamplesMany components of Wnt/-catenin signaling pathway also play critical roles in mammary tumor development. To study the role of Apc in mammary tumorigensis, we introduced conditional Apc mutations specifically into two different mammary epithelial populations using K14-Cre (progenitor) and WAP-cre (lactaing luminal) transgenic mice. Only the K14-cre mediated Apc heterozygosity developed mammary adenocarcinomas demonstrating histological and molecular heterogeneity, suggesting the progenitor cell origin of these tumors. These tumors harbored truncation mutation in a very defined region in the remaining wild-type allele of Apc that would retain some down-regulating activity of -catenin signaling. Our results suggest that not only the epithelial origin but also a certain Apc mutations are selected to achieve a specific level of -catenin signaling optimal for mammary tumor development.
Genetic mechanisms in Apc-mediated mammary tumorigenesis.
No sample metadata fields
View SamplesIn the normal prostate, most basal and some luminal cells are castration-resistant (CR). The identity of these CR cells and their relation to CR prostate cancer are unresolved. We compared single-cell expression profiles of prostate cells sorted from hormonally nave (HN) and castrated mice. We found both basal and luminal-localized cells, particularly the latter, were molecularly heterogeneous. CR luminal cells and a subset of HN luminal cells exhibited a similar intermediate expression pattern, including high-level expression of multiple prostate stem/progenitor marker genes and androgen receptor gene. We validated LY6D as a marker linking CR luminal cells to luminal progenitors. LY6D+ prostate cells, including LY6D+ luminal cells, were enriched for organoid-forming potential regardless of the presence or absence of androgen. Krt8-based lineage-tracing revealed that LY6D+ CR luminal cells produced LY6D- normal luminal cells upon regeneration, but LY6D+ luminal cancer cells under PTEN-deficiency. Furthermore, prostate cancers originating from CR luminal cells (LY6D+) exhibited a more advanced phenotype than those from HN luminal cells (LY6D+ or LY6D-). Lastly, LY6D amplification/upregulation appear associated with advanced prostate cancer in patient samples. Together, our studies demonstrate LY6D as a novel progenitor marker predictive of lethal CR disease.
Single-Cell Analysis Identifies LY6D as a Marker Linking Castration-Resistant Prostate Luminal Cells to Prostate Progenitors and Cancer.
Sex, Specimen part
View SamplesPPAR is a member of the nuclear receptor family for which agonist ligands have anti-growth effects. However, clinical studies using PPAR ligands as a monotherapy failed to show a beneficial effect. Here we have studied the effects of PPAR activation with chemotherapeutic agents in current use for specific cancers. We observed a striking synergy between rosiglitazone and platinum-based drugs in several different cancers both in vitro and using transplantable and chemically induced spontaneous tumor models. The effect appears to be due in part to PPAR-mediated downregulation of metallothioneins, proteins that have been shown to be involved in resistance to platinum-based therapy. These data strongly suggest combining PPAR agonists and platinum-based drugs for the treatment of certain human cancers
Synergy between PPARgamma ligands and platinum-based drugs in cancer.
No sample metadata fields
View Samples