Cell lines geneticially engineered to undergo conditional asymmetric self-renewal were used to identify genes whose expression is asymmetric self-renewal associated (ASRA). Non-random sister chromatid segregation occurs concordantly with asymmetric self-renewal in these cell lines.
A resource for discovering specific and universal biomarkers for distributed stem cells.
Cell lineView Samples
In human breast cancers, a phenotypically distinct minority population of tumorigenic cancer (TG) cells (sometimes referred to as cancer stem cells) drives tumor growth when transplanted into immunodeficient mice. Our objective was to identify a mouse model of breast cancer stem cells that could have relevance to studying human breast cancer. To do so, we utilized breast tumors of the MMTVWnt-1 mice. MMTV-Wnt-1 breast tumors were harvested, dissociated into single cell suspensions, and FACS sorted on Thy1, CD24, and CD45. FACS sorted cells were then injected into recipient background FBV/NJ female mice. Thy1+CD24+ cancer cells, which constitute approximately 1-4% of tumor cells were highly enriched for cells capable of regenerating new tumors when compared to cells of the tumor that did not fit this profile (Not Thy1+CD24+). Resultant tumors were of the same phenotypic diversity as the original tumor and behaved in a similar manner when passaged. Microarray analysis comparing Thy1+CD24+ tumor cells to Not Thy1+CD24+ cells identified a list of differentially expressed genes. Orthologs of these differentially expressed genes predicted survival of human breast cancer patients from two different study groups. These studies suggest that there is a cancer stem cell compartment in the MMTV-Wnt-1 murine breast tumor and that there is a clinical utility of this model for the study of cancer stem cells.
Isolation and molecular characterization of cancer stem cells in MMTV-Wnt-1 murine breast tumors.
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Breast cancers contain a minority population of cancer cells characterized by CD44 expression but low or undetectable levels of CD24 (CD44+CD24-/low) that have higher tumorigenic capacity than other subtypes of cancer cells. METHODS: We compared the gene-expression profile of CD44+CD24-/low tumorigenic breast-cancer cells with that of normal breast epithelium. Differentially expressed genes were used to generate a 186-gene invasiveness gene signature (IGS), which was evaluated for its association with overall survival and metastasis-free survival in patients with breast cancer or other types of cancer. RESULTS: There was a significant association between the IGS and both overall and metastasis-free survival (P<0.001, for both) in patients with breast cancer, which was independent of established clinical and pathological variables. When combined with the prognostic criteria of the National Institutes of Health, the IGS was used to stratify patients with high-risk early breast cancer into prognostic categories (good or poor); among patients with a good prognosis, the 10-year rate of metastasis-free survival was 81%, and among those with a poor prognosis, it was 57%. The IGS was also associated with the prognosis in medulloblastoma (P=0.004), lung cancer (P=0.03), and prostate cancer (P=0.01). The prognostic power of the IGS was increased when combined with the wound-response (WR) signature. CONCLUSIONS: The IGS is strongly associated with metastasis-free survival and overall survival for four different types of tumors. This genetic signature of tumorigenic breast-cancer cells was even more strongly associated with clinical outcomes when combined with the WR signature in breast cancer.
The prognostic role of a gene signature from tumorigenic breast-cancer cells.
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Juvenile hormone (JH) and 20-hydroxy-ecdysone (20E) are highly versatile hormones, coordinating development, growth, and reproduction in insects. Pulses of 20E provide key signals for initiating developmental and physiological transitions, while JH promotes or inhibits these signals in a stage-specific manner. Previous evidence suggests that JH and 20E might modulate innate immunity, but whether and how these hormones interact to regulate the immune response remains unclear. Here we show that JH and 20E have antagonistic effects on the expression of antimicrobial peptides (AMPs) in Drosophila melanogaster. In S2* cells challenged with bacterial peptidoglycans, 20E induces promoter activity and expression of AMPs in a dose-dependent manner, while JH III and its synthetic analogs (JHa) methoprene and pyriproxyfen abolish this 20E-dependent response. Using microarrays and GFP reporter gene assays in adult flies, we confirm that JH is a hormonal immuno-suppressor in vivo. When silencing both partners of the ecdysone receptor (EcR ) / ultraspiracle (USP) heterodimer with RNAi in S2* cells, 20E fails to activate Diptericin (Dpt) expression, suggesting that 20E regulates expression of this gene through EcR / USP signaling. In contrast, silencing methoprene-tolerant (MET), a candidate JH receptor, does not impair the immuno-suppressive action of JH III and JHa, indicating that in this context MET does not function as a JH receptor. Our results suggest that the balance of 20E and JH is a major determinant of immune homeostasis in insects.
Hormonal regulation of the humoral innate immune response in Drosophila melanogaster.
Induction of the Arf tumor suppressor in response to hyperproliferative stress following oncogene activation activates a p53-dependent transcriptional program that limits the expansion of incipient cancer cells. Although Arf is not expressed in most tissues of fetal or young adult mice, it is physiologically expressed in the fetal yolk sac, a tissue derived from the extraembryonic endoderm. We demonstrate that expression of the mouse p19Arf protein marks late stages of extraembryonic endoderm differentiation in cultured embryoid bodies derived from either embryonic stem cells or induced pluripotent stem cells, and that Arf inactivation specifically delays the differentiation of the extraembryonic endoderm lineage, but not the formation of other germ cell lineages from pluripotent progenitors. Arf is required for the timely induction of extraembryonic endodermal cells in response to Ras/Erk signaling and, in turn, acts through p53 to ensure extraembryonic endoderm lineage development, but not maintenance. Remarkably, a significant temporal delay in extraembryonic endoderm differentiation detected during the maturation of Arf-null embryoid bodies is rescued by enforced expression of miR-205, a micro-RNA up-regulated by p19Arf and p53. Introduction of miR-205 into Arf-null embryonic stem cells rescues defective ExEn formation and elicits a program of gene expression that controls the migration and adhesion of embryonic endodermal cells. This occurs, at least in part, through atypical regulation of genes that control the epithelial-to-mesenchymal transition in cancer cells. Our findings suggest that noncanonical and canonical roles of Arf in extraembryonic endoderm development and tumor suppression, respectively, may be conceptually linked through mechanisms that govern cell-to-cell attachment and migration.
Arf tumor suppressor and miR-205 regulate cell adhesion and formation of extraembryonic endoderm from pluripotent stem cells.
Specimen part, TreatmentView Samples
Chronic alcohol consumption can lead to alchohol-related brain damage (ARBD). Despite the well known acute effects of alcohol the mechanism responsible for chronic brain damage is largely unknown. Pathologically the major change is the loss of white matter while neuronal loss is mild and restricted to a few areas such as the prefrontal cortex. In order to improve our understanding of ARBD pathogenesis we used microarrays to explore the white matter transcriptome of alcoholics and controls.
Comorbidities, confounders, and the white matter transcriptome in chronic alcoholism.
Specimen part, Disease, Disease stageView Samples
The morphogen and mitogen, Sonic Hedgehog, activates a Gli1-dependent transcription program that drives proliferation of granule neuron progenitors (GNPs) within the external germinal layer of the postnatally developing cerebellum. Medulloblastomas with mutations activating the Sonic Hedgehog signaling pathway preferentially arise within the external germinal layer, and the tumor cells closely resemble GNPs. Atoh1/Math1, a basic helix-loop-helix transcription factor essential for GNP histogenesis, does not induce medulloblastomas when expressed in primary mouse GNPs that are explanted from the early postnatal cerebellum and transplanted back into the brains of nave mice. However, enforced expression of Atoh1 in primary GNPs enhances the oncogenicity of cells overexpressing Gli1 by almost three orders of magnitude. Unlike Gli1, Atoh1 cannot support GNP proliferation in the absence of Sonic Hedgehog signaling and does not govern expression of canonical cell cycle genes. Instead, Atoh1 maintains GNPs in a Sonic Hedgehog-responsive state by regulating genes that trigger neuronal differentiation, including many expressed in response to bone morphogenic protein-4. Therefore, by targeting multiple genes regulating the differentiation state of GNPs, Atoh1 collaborates with the pro-proliferative Gli1-dependent transcriptional program to influence medulloblastoma development.
Atoh1 inhibits neuronal differentiation and collaborates with Gli1 to generate medulloblastoma-initiating cells.
Age, Specimen part, TreatmentView Samples
Myc-driven Group 3 medulloblastoma (MB) is the most aggressive tumor among the four subgroups classified by transcriptome, genomic landscape and clinical outcomes. So far in all available mouse Group 3 models, the constitutive ectopic Myc expression was under control of LTR element or other exogenous promoters within the vectors, which were randomly inserted into the genome with multiple copies. Here we are deploying nuclease deficient CRISPR/dCas9-based transactivator that is targeted to promoter DNA sequences by specific guide RNA to force the transcriptional activation of endogenous Myc in p53-/-;cdkn2c-/- neurospheres cells. A combination of three sgRNAs together with dCas9-VP64 induced the highest expression of endogenous Myc. When the targeted cells were transplanted to the cortex of recipients, tumors arose fully recapitulate the Group 3 MB in human. This novel mouse model should significantly strengthen our understanding and treatment of the Myc-driven Group 3 medulloblastoma.
Mouse medulloblastoma driven by CRISPR activation of cellular Myc.
Specimen partView Samples
Hsp70 inhibition affects many signaling pathways. We established how these effects are translated into changes in gene expression.
Cancer cell responses to Hsp70 inhibitor JG-98: Comparison with Hsp90 inhibitors and finding synergistic drug combinations.
Cell lineView Samples
DrugMatrix is a comprehensive rat toxicogenomics database and analysis tool developed to facilitate the integration of toxicogenomics into hazard assessment. Using the whole genome and a diverse set of compounds allows a comprehensive view of most pharmacological and toxicological questions and is applicable to other situations such as disease and development.
Genomic models of short-term exposure accurately predict long-term chemical carcinogenicity and identify putative mechanisms of action.
Sex, Specimen part, Compound, TimeView Samples