Gene expression changes in oncogenic Kras-containing, Apc-mutated mouse intestinal organoids in the presence or absence of TGF-beta
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ABSTRACT: We isolated and selected intestinal adenoma organoids from Apc1638N/+ and Apc1638N/+; Kras mice. After the selection procedure, we maintained the cultures with or without TGF-beta for 18h. RNA was isolated to determine the effect of oncogenic Kras on the gene expression changes. Total RNA obtained from Apc1638N/+; Kras organoids were compared to Apc1638N/+ samples in the absence or presence of 3 ng/ml TGF-beta (18h).
Project description:We isolated and selected intestinal adenoma organoids from Apc1638N/+ and Apc1638N/+; Kras mice. After the selection procedure, we maintained the cultures with or without TGF-beta for 18h. RNA was isolated to determine the effect of oncogenic Kras on the gene expression changes.
Project description:Intestinal crypts isolated from Apcflox/flox; villin-CreERT mice were treated with Tamoxifen to induce the deletion of Apc. Tamoxifen-treated organoids were selected in the absence of Wnt agonists and then treated with TGF-beta. Total RNA obtained from Tamoxifen-treated, Apc-deleted intestinal organoids in the absence or presence of 3 ng/ml TGF-beta (18h).
Project description:We isolated and selected intestinal adenoma organoids from Lgr5-EGFP-IRES-CreER; Apcflox/flox mice and added tamoxifen to induce the deletion of the Apc gene in the intestinal stem cells. Gene expressions on day7 and day20 after the addition of tamoxifen were compared, representing two stages with different colorectal cancer stem cell content. Total RNA obtained from Lgr5-EGFP-IRES-CreER; Apcflox/flox organoids were compared 7 days and 20 days after the addition of tamoxifen, cultured without the Wnt-agonist R-Spondin1.
Project description:We isolated and selected intestinal adenoma organoids from villin-CreER; Apcflox/flox and villin-CreER; Apcflox/flox; Prox1flox/flox mice and added tamoxifen to induce the deletion of the Apc and Prox1 genes in the intestinal epitheliul ex vivo. Microarray experiments were carried out 7 days after the addition of tamoxifen. Total RNA obtained from villin-CreER; Apcflox/flox and villin-CreER; Apcflox/flox; Prox1flox/flox organoids were compared 7 days after the addition of tamoxifen and 5 days after the selection for Apc-mutant organoids in the absence of the Wnt-agonist R-Spondin1.
Project description:Constitutive activation of the Wnt pathway leads to adenoma formation, an obligatory step towards intestinal cancer. In view of the established role of Wnt in regulating stemness, we attempted the isolation of cancer stem cells (CSCs) from Apc- and Apc/KRAS-mutant intestinal tumours. Whereas CSCs are present in malignant Apc/KRAS–mutant carcinomas, they appear to be very rare (<10-6) in the benign Apc–mutant adenomas. In contrast, the Lin-CD24hiCD29+ subpopulation of adenocarcinoma cells appear to be enriched in CSCs with increased levels of active -catenin. Expression profiling analysis of the CSC-enriched subpopulation confirmed their enhanced Wnt activity and revealed additional differential expression of other signalling pathways, growth factor binding proteins, and extracellular matrix components. As expected, genes characteristic of the Paneth cell lineage (e.g. defensins) are co-expressed together with stem cell genes (e.g. Lgr5) within the CSC-enriched subpopulation. This is of interest as it may indicate a cancer stem cell niche role for tumor-derived Paneth-like cells, similar to their role in supporting Lgr5+ stem cells in the normal intestinal crypt. Overall, our results indicate that oncogenic KRAS activation in Apc-driven tumours results in the expansion of the CSCs compartment by increasing b-catenin intracellular stabilization. To identify molecular differences between stem-like and more differentiated (bulk) tumour cells from Apc1638N/+ and Apc1638N/+/KRASV12G intestinal adenomas and adenocarcinomas, we isolated total RNA from 104 Lin-CD24hiCD29+, Lin-CD24medCD29+/Lin-CD24loCD29+ and Lin- (bulk) tumour cells from 5 individual mice of each genotype (Apc1638N/+ and Apc1638N/+/KRASV12G). Total RNA samples were then employed to hybridize oligonucleotide microarrays (Affymetrix Mouse Genome 430A 2.0 Array) according to conventional protocols.
Project description:Intestinal crypts isolated from Apcflox/flox; villin-CreERT mice were treated with Tamoxifen to induce the deletion of Apc. Tamoxifen-treated organoids were selected in the absence of Wnt agonists and then treated with TGF-beta.
Project description:We revealed that concurrent activation of the Kras and canonical Wnt pathways resulted in formation of ICPN and BilIN, which could develop into biliary cancer. We found that c-Myc contributed to tumorigenesis, whereas Tgf-β pathway inhibited it.
Project description:For organoid preparation, we first treated the following 4 groups of 8-12 week old mice with tamoxifen: 1) CDX2P-CreERT2, Apc flox/+, Kras LSL-G12D/+, Trp53 flox/flox mice (n=2); 2) CDX2P-CreERT2, Apc flox/+, Kras LSL-G12D/+,Trp53 R270H/flox mice (n=3); 3) CDX2P-CreERT2, Apc flox/flox mice (n=3); 4) Wild-type control mice (n=4). The CDX2P-CreERT2 transgene expresses a tamoxifen (TAM)-regulated Cre protein (CreERT2) under control of human CDX2 regulatory sequences, allowing for TAM-inducible targeting of flox alleles in adult mouse terminal ileum, cecum, and colon epithelium. Treating the mice having CDX2P-CreERT2 transgene with tamoxifen permits the Cre recombinase to enter the cell nucleus and recombine the floxed alleles for Apc, Kras, and Trp53, resulting in deletion mutations in Apc and Trp53, and an activating, oncogenic mutation in Kras (G12D mutation). The Trp53 R270H allele carries a constitutive R270H mutation, which is the mouse equivalent of human TP53 R273H mutation. Colon tumors were induced by TAM treatment in all the mice from the first three groups and organoids were derived from the tumors of each mouse. We also derived organoids from the normal colon epithelium in the 4th group of mice as controls. All organoids were generated and propagated using a slightly modified TMDU protocol as described in PMID:20872391. Organoids were cultured for 4 days and then harvested. RNA was purified from the organoids, and targets for Affymetrix arrays were synthesized from the mRNAs. We used Affymetrix Mouse Gene 2.1 ST plate arrays, which hold 41345 probe-sets, but we largely analyzed just those 24562 probe-sets that were mapped to Entrez gene IDs. Raw data was processed with the Robust Multi-array Average algorithm (RMA). Data is log2-transformed transcript abundance estimates. We fit a one-way ANOVA model to the 4 groups of samples. We supply a supplementary excel workbook that holds the same data as the data matrix file for those 24562 probe-sets, but also holds the probe-set annotation at the time we analyzed the data, and some simple statistical calculations, which selects subsets of the probe-sets as differentially expressed between pairs of groups. It also shows data and analysis from a separate experiment of RNA purified directly from 3 groups of mice with genotypes like those of the organoid data except that no group of mice with CDX2P-CreERT2 Apc flox/flox genotype were used. It also joins a statistical summary of differences between 9 human tumors with TP53 missense mutations at codon 273 and 36 tumors with TP53 null mutations assayed with RNA-seq by the TCGA project. A separate supplementary file of the TCGA data is also provided. Consumers should consider obtaining more up-to-date probe-set annotation for the array platform.