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Comparison of KrasG12D/WT;p53Fx/Fx and KrasG12D/G12D;p53Fx/Fx MEFs

ABSTRACT: Microarray expression data generated to compare the biological impact of KrasG12D allelic duplication in p53null mouse embryonic fibroblasts (MEFs). The RAS/MAPK-signalling pathway is frequently deregulated in non-small cell lung cancer (NSCLC), often through activating mutations in KRAS. Mouse models demonstrated that activation of a single endogenous mutant Kras allele is sufficient to promote lung tumour formation, but acquisition of other genetic alterations is required for malignant progression. Using a well-established lung cancer mouse model we recently demonstrated that advanced KrasG12D-driven spontaneous tumours frequently exhibit enhanced MAPK signalling and KrasG12D allelic enrichment (KrasG12D/Kraswild-type>1), implying that mutant Kras copy gains are positively selected during lung cancer progression. To compare the oncogenic impact of a single mutant allele versus additional mutant Kras copy gain, we carried out a comprehensive analysis of mutant Kras homozygous and heterozygous MEFs and lung cancer cells and show that these genotypes are phenotypically distinct. Title: Mutant Kras copy number defines metabolic reprogramming and therapeutic susceptibilities Authors: Emma M Kerr, Edoardo Gaude, Frances K Turrell, Christian Frezza and Carla P Martins

ORGANISM(S): Mus musculus

PROVIDER: GSE75871 | GEO | 2016/02/24

SECONDARY ACCESSION(S): PRJNA305579

REPOSITORIES: GEO

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Project description:The small G-protein KRAS is crucial for mediating gonadotropin-induced events associated with ovulation. However, constitutive expression of KrasG12D in granulosa cells disrupted normal follicle development leading to the persistence of abnormal follicle-like structures containing non-mitotic cells. To determine what factors mediate this potent effect of KrasG12D, gene profiling analyses were done. We also analyzed KrasG12D;Cyp19-Cre and KrasG12D;Pgr-Cre mutant mouse models that express Cre prior to or after the initiation of granulosa cell differentiation, respectively. KrasG12D induced cell cycle arrest in granulosa cells of the KrasG12D;Cyp19-Cre mice but not in the KrasG12D;Pgr-Cre mice, documenting the cell context specific effect of KrasG12D. Expression of KrasG12D silenced the Kras gene, reduced cell cycle activator genes and impaired expression of granulosa cell and oocyte specific genes. Conversely, levels of PTEN and phosphorylated p38MAPK increased markedly in the mutant granulosa cells. Because disrupting Pten in granulosa cells leads to increased proliferation and survival, Pten was disrupted in the KrasG12D mutant mice. The Pten/Kras mutant mice were infertile but lacked GCTs. By contrast, the Ptenfl/fl;KrasG12D;Amhr2-Cre mice developed aggressive ovarian surface epithelial (OSE) cell tumors that did not occur in the Ptenfl/fl;KrasG12D;Cyp19-Cre or Ptenfl/fl;KrasG12D;Pgr-Cre mouse strains. These data document unequivocally that Amhr2-Cre is expressed in and mediates allelic recombination of oncogenic genes in OSE cells. That KrasG12D/Pten mutant granulosa cells do not transform but rather undergo cell cycle arrest indicates that they resist the oncogenic insults of Kras/Pten by robust self-protecting mechanisms that silence the Kras gene and elevate PTEN and phospho-p38MAPK. Experiment Overall Design: Whole ovaries were collected from 26-day-old wild type mice, 26-day-old K-ras conditional mutant mice and 3-month-old K-ras conditional mutant mice. The gene expression profiles of these samples were compared using microarray method.

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Comparison of KrasG12D/WT;p53Fx/Fx and KrasG12D/G12D;p53Fx/Fx MEFs

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