Project description:This SuperSeries is composed of the following subset Series:; GSE14449: Gene expression profiles of spontaneous metastasis in a K-ras/p53 mutant mouse model; GSE14458: Gene expression profiles of 344SQ lung adenocarcinoma cells with high metastatic potential (syngeneic mouse model) Experiment Overall Design: Refer to individual Series
Project description:Salivary tumors isolated from MMTV-ras transgenic mice expressing wild-type p53, no p53 or p53R172H gain-of-funcion mutant were subjected to genome-wide gene expression profiling to assess the effect of the different p53 status on tumor gene expression. A total of 12 spontaneous salivary tumors from MMTV-ras/p53+/+, MMTV-ras/p53-/- or MMTV-ras/p53R172H/R172H mice (4 tumors per genotype) were analyzed using Affymetric GeneChip for gene expression profiling. The multi-class comparison function of Significance Analysis of Microarray (SAM) with an FDR of 1% was used to identify genes that are differentially regulated across the three genotypic groups.
Project description:Whole Exome Sequencing of cohorts of Mutant Braf mouse model melanoma DNA and germline DNA. The cohorts are (1) Mutant Braf mouse model melanomas, (2) Mutant Braf mouse model melanomas from UVR exposed mice and (3) Mutant Braf mouse model melanomas from UVR exposed, sunscreen protected mice.
Project description:<p>Although multi-agent combination chemotherapy is curative in a significant fraction of childhood acute lymphoblastic leukemia (ALL) patients, 20% of cases relapse and most die due to chemo-refractory disease. Here we used whole-exome and whole-genome sequencing to analyze the mutational landscape and pattern of clonal evolution at relapse in pediatric ALL cases. These analyses showed that ALL relapses originate from a common ancestral precursor clone of the diagnosis and relapsed populations and frequently harbor mutations implicated in chemotherapy resistance. RAS-MAPK pathway activating mutations in NRAS, KRAS and PTPN11 were present in 24/55 (44%) cases in our series. Notably, while some cases showed emergence of RAS mutant clones at relapse, in others, RAS mutant clones present at diagnosis were replaced by RAS wild type populations. Mechanistically, functional dissection of mouse and human wild type Kras and mutant Kras (Kras G12D) isogenic leukemia cells demonstrated induction of methotrexate resistance, but also improved response to vincristine, in mutant Kras- expressing lymphoblasts. These results identify chemotherapy driven selection as a central mechanism of leukemia clonal evolution and pave the road for the development of tailored personalized therapies for the treatment of relapsed ALL. </p>
Project description:The specific roles of mutant p53’s dominant-negative (DN) or gain-of-function (GOF) properties in regulating acute response and long-term tumorigenesis is unclear. Using “knock-in” mouse strains expressing varying R246S mutant levels, we show that DN effect on transactivation is universally observed after acute p53 activation whereas the effect on cellular outcome is cell-type specific. Reducing mutant p53 levels abrogated the DN effect. Mutant p53’s DN effect protected against radiation-induced death, but did not accentuate tumorigenesis. Furthermore, the R246S mutant did not promote tumorigenesis compared to p53-/- mice in various models, even in the absence of MDM2, unlike the R172H mutant. Together, these data demonstrate that mutant p53’s DN property only affects acute responses, whereas GOF is not universal, being mutation-type specific. Transcriptomes of mouse embryonic fibroblasts harvested from embyros of different p53 genotypes were profiled. A total of 6 primary clones of MEFs were used and these cells were transformed with E1A/Ras. Data was analysed by mixed model ANOVA using Partek.
Project description:Tumor cells that give rise to metastatic disease are a primary cause of cancer-related death and have not been fully elucidated in patients with lung cancer. Here, we addressed this question by using tissues from a mouse that develops metastatic lung adenocarcinoma owing to expression of mutant K-ras and p53. We identified a metastasis-prone population of tumor cells that differed from those with low metastatic capacity on the basis of having sphere-forming capacity in Matrigel cultures, increased expression of CD133 and Notch ligands, and relatively low tumorigenicity in syngeneic mice. Knockdown of jagged1 or pharmacologic inhibition of its downstream mediator phosphatidylinositol 3-kinase abrogated the metastatic but not the tumorigenic activity of these cells. We conclude from these studies on a mouse model of lung adenocarcinoma that CD133 and Notch ligands mark a population of metastasis-prone tumor cells and that the efficacy of Notch inhibitors in metastasis prevention should be explored. Keywords: two group comparison 344SQ subcutaneous tumors (from a lung adenocarcinoma cell line derived from a KrasLA1/+; p53R172HdelG/+ mouse that metastasizes widely following subcutaneous injection into syngeneic mice) were sorted by flow cytometry into CD133high and CD133low fractions. RNA samples from these fractions were processed and analyzed on Affymetrix Mouse Expression Array 430A 2.0 chips.
Project description:Tumor cells that give rise to metastatic disease are a primary cause of cancer-related death and have not been fully elucidated in patients with lung cancer. Here, we addressed this question by using tissues from a mouse that develops metastatic lung adenocarcinoma owing to expression of mutant K-ras and p53. We identified a metastasis-prone population of tumor cells that differed from those with low metastatic capacity on the basis of having sphere-forming capacity in Matrigel cultures, increased expression of CD133 and Notch ligands, and relatively low tumorigenicity in syngeneic mice. Knockdown of jagged1 or pharmacologic inhibition of its downstream mediator phosphatidylinositol 3-kinase abrogated the metastatic but not the tumorigenic activity of these cells. We conclude from these studies on a mouse model of lung adenocarcinoma that CD133 and Notch ligands mark a population of metastasis-prone tumor cells and that the efficacy of Notch inhibitors in metastasis prevention should be explored. Keywords: two group comparison