ABSTRACT: The experiment is a study of the effects of signal strength in the Ras pathway. In particular, we studied a gain-of-function mutant of Kras, KrasG12D. We generated these mutant mice and performed microarray analyses on RNA extracted from whole skin, comparing KrasG12D mice to wild-type mice, with three replicates of each.
Project description:Mice bearing a G12D activating mutation in Kras consistently develop lung adenocarcinomas in a manner analogous to humans. By performing small and large RNA sequencing on KrasG12D tumors from F1 hybrid mice we were able to identify genes and microRNAs differentially expressed in these tumor samples. Quantification of reads that cover single nucleotide polymorphisms that distinguish between the parental mouse strains enabled an analysis of allele specific expression and imprinting status in these tumors. mRNA and small RNA fractions of mouse lungs and lung adenocarcinomas were deep sequenced in triplicate
Project description:We utilized non-transformed, human pancreatic ductal epithelial (HPDE) cells, previously engineered with the E6 and E7 proteins of the HPV16 virus to emulate loss of p53 and inactivation of the Rb pathway, respectively. Given the frequent activation of KRAS (>90% PDAC tumors) and its early role in pancreatic neoplasia, we sought to engineer HPDE cells containing KRASG12D to provide the appropriate context in which to screen for novel drivers that might represent KRAS effectors. The KRAS-induced transcription analysis was conducted using RNAs extracted from HPDE cells transduced with either control, wild-type KRAS or KRASG12D(pInducer) with or without DOX (100ng/ml) for 72 h, followed by hybridization of labeled cDNA onto Agilent arrays (Agilent G3 Human GE 8x60K) by the Baylor College of Medicine Genome Profiling Core Facility. multi-group comparison
Project description:We wished to investigate the role of E-cadherin loss in our mouse parietal cell/pre-parietal cell E-cadherin knock-out, p53 knock-out, oncogenic Kras induced model of gastric cancer. As such, we isolated RNA from stomach tissue from our E-cadherin knock-out model (Atp4b-Cre;Cdh1(fl/fl);Kras(LSL-G12D/+);Trp53(fl/fl);Rosa26(LSL-YFP/LSL-YFP)) and our E-cadherin heterozygous model (Atp4b-Cre;Cdh1(fl/+);Kras(LSL-G12D/+);Trp53(fl/fl);Rosa26(LSL-YFP/LSL-YFP)). We then performed a microarray on this stomach tissue from four independent mice of each genotype. Differentially expressed genes were identified and gene set overlap analysis was used to identify pathways enriched in one model over the other.
Project description:Inflammatory transcription networks have been linked with the development of pancreatic ductal adenocarcinoma (PDAC). Here, we demonstrate that NFATc1 is both necessary and sufficient to drive progression of KrasG12D-initiated PDAC, particularly in the context of inflammation. Significantly, nuclear NFATc1 accelerates PDAC development in KrasG12D mice, whereas conditional NFATc1 deletion or pharmacological inhibition attenuates inflammation-mediated carcinogenesis. Mechanistically, NFATc1 induces STAT3 expression, complex formation and signal integration in PDAC. Genome-wide ChIP-sequencing and expression analysis in cells derived from c.n.NFATc1;KrasG12D mice identified combinatorial NFATc1/STAT3 binding at chromatin enhancer sites and subsequent regulation of key molecules involved in oncogenic signaling, growth and inflammation. Together, this study supports the relevance of inflammatory transcription factor networks in pancreatic carcinogenesis and provides a theoretical platform for therapeutic targeting of NFATc1 nucleoprotein complexes in PDAC. NFATc1 ChIP followed by high throughput sequencing in primary murine pancreatic cancer cells (referred to as NKC cells) derived from transgenic mice with pancreas-specific constitutive activation of NFATc1 and KrasG12D mutation in the presence or absence of STAT3 shRNA; 2 ChIP samples (scramble DNA and shSTAT3 DNA) and 1 unenriched input control from the same chromatin pool.
Project description:Cancer cachexia syndrome is observed in 80% of patients with advanced-stage cancer, and it is one of the most frequent causes of death. Severe wasting accounts for more than 80% in patients with advanced pancreatic cancer. Here we wanted to define, by using an microarray approach and the Pdx1-cre;LSL-KrasG12D;INK4a/arffl/fl, the pathways involved in muscle, liver and white adipose tissue wasting. The aim of our work was to characterize as extensively as possible the pathways activated by the pancreatic cancer-induced cachectic tissues. For this purpose, we generated and compared genome-wide expression profiles of white adipose tissue, skeletal muscle and liver, from Pdx1-cre;LSL-KrasG12D;INK4a/arffl/fl and LSL-KrasG12D;INK4a/arffl/fl mice at 10 weeks-old. Tissue samples by triplicate was obtained from liver, muscle and adipose tissues in both groups, controls and cachectic mice. Total RNA samples was processed and profiled on Affymetrix Mouse Gene 1.0 ST arrays as previously described (Cano et al, 2012)
Project description:In some organs, adult stem cells are uniquely poised to serve as cancer cells of origin1-4. It is unclear, however, whether tumorigenesis is influenced by the activation state of the adult stem cell. Hair follicle stem cells (HFSCs) act as cancer cells of origin for cutaneous squamous cell carcinoma (SCC) and undergo defined cycles of quiescence and activation. The data presented here show that HFSCs are unable to initiate tumors during the quiescent phase of the hair cycle, indicating that the mechanisms that keep HFSCs dormant are dominant to the gain of oncogenes (Ras) or the loss of tumor suppressors (p53). Furthermore, Pten activity is necessary for quiescence based tumor suppression, as its deletion alleviates tumor suppression without affecting proliferation. These data demonstrate that stem cell quiescence is a form of tumor suppression in HFSCs, and that Pten plays a role in maintaining quiescence in the presence of tumorigenic stimuli. This experiment includes RNA profiling of hair follicle stem cells at various stages of tumorigenesis Briefly: HFSCs were lineage traced with YFP allele, FACS isolated from various genotypes, and then profiled by Affymetrix microarray Cell Isolation and FACS: Whole dorsal and ventral mouse K15-CrePR; LSLYFP, K15-CrePR; KrasG12D; LSLYFP and K15-CrePR; KrasG12D; Ptenff; LSLYFP was extracted, diced and digested with collagenase (20mg/ml) for 2 hours at 37C, then an equal volume of .25% trypsin was added and digestion continued for an additional hour at 37C. Digested tissue was mechanically dispersed via pipette and filtered with a 100uM cell strainer, collected at 300g and washed twice with PBS. The cells were then filtered through a 40uM cell strainer and FACS processed. YFP+ and YFP- cell populations were collected in RNA lysis buffer (Stratagene) and stored at -80C. Gene expression profiling Microarray analyses by GeneSpring software were performed
Project description:Although mutations in Kras are present in 21% of lung tumors, there is a high level of heterogeneity in phenotype and outcomes amongst lung cancer patients suggesting the importance of other pathways. Wnt/β-catenin signaling is a known oncogenic pathway that plays a well defined role in colon and skin cancer but its role in lung cancer remains unclear. We show that activation of Wnt/β-catenin in the bronchiolar epithelium of the adult lung does not promote tumor development by itself. However, activation of Wnt/β- catenin signaling leads to a dramatic increase in tumor formation both in overall tumor number and size compared to KrasG12D alone. We show that activation of Wnt/β- catenin signaling significantly alters the KrasG12D tumor phenotype resulting in a phenotypic switch from bronchiolar epithelium to the highly proliferative distal progenitors found in the embryonic lung. This is associated with a decrease in E- cadherin expression at the cell surface which may increase metastasis in Wnt/β-catenin signaling positive tumors. Together, these data suggest that activation of Wnt/β-catenin signaling in combination with other oncogenic pathways in lung epithelium may lead to a more aggressive phenotype due to the imposition of an embryonic distal progenitor phenotype accompanied by decreased E-cadherin expression. We performed microarray analysis of control murine lung, CC10-cre:KrasG12D, and CC10-cre:Ctnnb1ex3flox:LSL-KrasG12D double mutant micro-dissected murine lung tumors to determine their transcriptional phenotype. Lungs of five-month-old mice were PBS inflated and all the tumors in each lobe were dissected. The total number of tumors obtained from three out of the 5 pulmonar lobes of each animal was called a sample the other two lobes were saved in case there were problems and the array needed to be repeated. Trizol was used to isolate RNA for microarray analysis. Samples & Genotypes: control murine lung n=2 animals, CC10-cre:KrasG12D n=2 animals, and CC10-cre:Ctnnb1ex3flox:LSL-KrasG12D n=2 animals.
Project description:Breast Cancer (BC) has been associated with alterations in signaling through a number of growth factor and hormone regulated pathways. Mouse models for metastatic BC have been developed using oncoproteins that activate PI3K, Stat3 and Ras signaling. To determine the role of each pathway, we analyzed mouse mammary tumor formation when they were activated singly or pairwise. We used microarrays to detect differentially expressed genes in the KRas(G12D/+);CreT and R26(H1047R/+);KRas(G12D/+);CreT tumors Total RNA was extracted from tumors developed by Qiagen RNAeasy kit and hybridized on Affymetrix microarrays.
Project description:Constitutive Kras and NF-kappaB activation is identified as signature alterations in human pancreatic ductal adenocarcinoma (PDAC). However, the mechanisms of constitutive NF-kappaB activation in KrasG12D-induced PDAC are not yet understood. Here, we report that pancreas-targeted IKK2/beta inactivation inhibited NF-kappaB activation and completely suppressed PDAC development in KrasG12D and KrasG12D;Ink4a/Arf mutant mice, demonstrating a genetic link between IKK2/beta and KrasG12D in PDAC inception. Our findings reveal that KrasG12D-activated AP-1 induces IL-1alpha, which in turn activates NF-kappaB and its target genes IL-1alpha and p62, to initiate IL-1alpha/p62 feedforward loops for inducing and sustaining NF-kappaB activity. Furthermore, IL-1alpha overexpression correlates with Kras mutation, constitutive NF-kappaB activity, and poor survival in PDAC patients. Therefore, our findings establish a pathway linking duel feedforward loops of IL-1alpha/p62 through which IKK2/beta/NF-kappaB is activated by KrasG12D. To study Kras-induced inflammatory responses and to identify differentially expressed genes between the pancreatic tissues of Pdx1-Cre;KrasLSL-G12D and Pdx1-Cre;KrasLSL-G12D;IKK2/betaF/F mice, cDNA microarray analysis was performed.
Project description:To assess the transcriptional profile within tumours AhcreERTR26flEYFP/wt LSL Kras+/G12D animals were treated with diethylnitrosamine for 8 weeks prior to induction of the Kras allele with a single dose of β-naphthoflavone (20 mg/kg) and tamoxifen (0.25 mg). Subsequently, animals were treated with Sorafenib for 6 weeks. Gene expression array analysis was performed on 12 squamous cell carcinomas (SCCs) from 4 animals.