To examine the role of Rb1 in gastrointestinal (GI) tumors we generated mice with an Apc1638N allele, Rbtm2brn floxed alleles, and a villlin-cre transgene (RBVCA). These mice had reduced median survival due to an increase in tumor incidence and multiplicity in the cecum and the proximal colon; they differed from murine intestinal tumors of the Apc1638N type which normally arise solely in the small intestine. We have examined by micro-array analysis three cecal tumors from these mice (probable adenomas), and compared them to three duodenal tumors (probable adenocarcinomas). Expression profiles of duodenal and cecal tumors relative to each other show unique gene subsets up and down regulated. The two tumor types were subsequently shown to differentially regulate distinct sets of genes over expressed in a majority of human colorectal carcinomas.
Loss of Rb1 in the gastrointestinal tract of Apc1638N mice promotes tumors of the cecum and proximal colon.
No sample metadata fields
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 SamplesThis SuperSeries is composed of the SubSeries listed below.
A systems analysis identifies a feedforward inflammatory circuit leading to lethal influenza infection.
Sex, Specimen part
View SamplesTranscriptomic comparison of 5 cell types during lethal and non-lethal influenza infection and further use of these signatures in a top-down systems analysis investigating the relative pathogenic contributions of direct viral damage to lung epithelium vs. dysregulated immunity during lethal influenza infection.
A systems analysis identifies a feedforward inflammatory circuit leading to lethal influenza infection.
Sex, Specimen part
View SamplesThe overall goal of our studies is to elucidate the cellular and molecular mechanism by which the transcription factor Casz1 functions in murine heart development. We established that Casz1 is expressed in myocardial progenitor cells beginning at E7.5 and in differentiated cardiomyocytes throughout development. We generated conditional Casz1 knockout mice to show that ablation of CASZ1 in Nkx2.5-positive cardiomyocytes leads to cardiac hypoplasia, ventricular septal defects and lethality by E13.5. To identify the pathways and networks by which Casz1 regulates cardiomyocyte development, we used RNA-Seq and identified genes involved in cell proliferation are upregulated in Casz1 mutants compared to wild-type littermates. We conclude that Casz1 is essential for cardiac development and has a pivotal role in regulating part of the cardiac transcriptional program. Overall design: 3 biological replicates of the two genotypes (Nkx2-5+/+,Casz1f/+ and Nkx2-5Cre/+,Casz1f/f) were used for RNA-seq to determine genes that are differentially expressed in the murine heart when Casz1 is mutated. Nkx2-5+/+,Casz1f/+ were used as wild-type controls for comparison.
Casz1 is required for cardiomyocyte G1-to-S phase progression during mammalian cardiac development.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Prospective identification of resistance mechanisms to HSP90 inhibition in KRAS mutant cancer cells.
Cell line
View SamplesInhibition of the HSP90 chaperone results in depletion of many signaling proteins that drive tumorigenesis, such as downstream effectors of KRAS, the most commonly mutated human oncogene. As a consequence, several small-molecule HSP90 inhibitors are being evaluated in clinical trials as anticancer agents. To prospectively identify mechanisms through which HSP90-dependent cancer cells evade pharmacologic HSP90 blockade, we generated multiple mutant KRAS-driven cancer cell lines with acquired resistance to the purine-scaffold HSP90 inhibitor PU-H71. All cell lines retained dependence on HSP90 function, as evidenced by sensitivity to short hairpin RNA-mediated suppression of HSP90AA1 or HSP90AB1 (also called HSP90 and HSP90, respectively), and exhibited two types of genomic alterations that interfere with the effects of PU-H71 on cell viability and proliferation: (i) a Y142N missense mutation in the ATP-binding domain of HSP90 that co-occurred with amplification of the HSP90AA1 locus, (ii) genomic amplification and overexpression of the ABCB1 gene encoding the MDR1 drug efflux pump. In support of a functional role for these alterations, exogenous expression of HSP90 Y142N conferred PU-H71 resistance to HSP90-dependent cells, and pharmacologic MDR1 inhibition with tariquidar or lowering ABCB1 expression restored sensitivity to PU-H71 in ABCB1-amplified cells. Finally, comparison with structurally distinct HSP90 inhibitors currently in clinical development revealed that PU-H71 resistance could be overcome, in part, by ganetespib (also known as STA9090) but not tanespimycin (also known as 17-AAG). Together, these data identify potential mechanisms of acquired resistance to small molecules targeting HSP90 that may warrant proactive screening for additional HSP90 inhibitors or rational combination therapies.
Prospective identification of resistance mechanisms to HSP90 inhibition in KRAS mutant cancer cells.
Cell line
View SamplesMYCN-high and MYCN-low neuroblastoma cells differ in their responses to Doxorubicin treatment. To explain this difference we compared the global trancriptomes of MYCN-high and MYCN-low cells before, during and after treatment. Overall design: MYCN-high cells without doxycyline and MYCN-low cells with doxycycline were treated with 0.1µg/ml Doxorubicin. Transcriptome was measured for the following time points: in untreated cells, in cells which were treated with Doxorubicin for 72 hours, and in cells collected three, eight and fourteen days after Doxorubin washout. Experiment was performed in biological duplicate.
Cell-Cycle Position of Single MYC-Driven Cancer Cells Dictates Their Susceptibility to a Chemotherapeutic Drug.
Treatment, Subject, Time
View SamplesMouse haematopoietic stem cells (HSCs) undergo a post-natal transition in several properties, including a marked reduction in their self-renewal activity. We now show that the developmentally timed change in this key function of HSCs is associated with their decreased expression of Lin28b and an accompanying increase in their let-7 microRNA levels. Lentivirus(LV)-mediated overexpression of Lin28 in adult HSCs elevates their self-renewal activity in transplanted irradiated hosts, as does overexpression of Hmga2, a well-established let-7 target that is upregulated in fetal HSCs. Conversely, HSCs from fetal Hmga2-/- mice do not display the heightened self-renewal activity that is characteristic of wild-type fetal HSCs. Interestingly, overexpression of Hmga2 in adult HSCs does not mimic the ability of elevated Lin28 to activate a fetal lymphoid differentiation program. Thus Lin28b may act as a master regulator of developmentally timed changes in HSC programs with Hmga2 serving as its specific downstream modulator of HSC self-renewal potential.
The Lin28b-let-7-Hmga2 axis determines the higher self-renewal potential of fetal haematopoietic stem cells.
Specimen part
View SamplesGene expression in NPM1 wildtype and mutated AML patients with high or low hsa_circ_0075001 expression
Circular RNAs of the nucleophosmin (NPM1) gene in acute myeloid leukemia.
Specimen part, Disease, Disease stage
View Samples