Project description:Colorectal cancer (CRC) is the third most diagnosed cancer and the second leading cause of cancer-related death worldwide Unique combinations of mutations can affect responsiveness to specific therapeutics. This can be, at least in part, due to mutation-specific alterations in gene regulatory mechanisms. To better understand how unique combinations of mutations affect gene regulation, we generated small RNA-seq, length extension chromatin run-on-seq (leChRO-seq), and RNA-seq data from APC (A-mutant), APC/KRAS (AK-mutant), APC/KRAS/TP53 mutant (AKP-mutant), and iGFP control human colonic organoids. From these analyses, we found that our colonic organoid models demonstrate mutation-specific patterns of miRNA transcription, miRNA expression and transcriptional regulatory element actvitiy. Furthermore, we defined 10 patterns of miRNA expression across organoid models. We highlighted one group of miRNAs that exhibited a unique downregulation of expression in AKP-mutant organoids (including miR-34a-5p and miR-10a-5p). Analysis of miRNA transcription revealed that most changes in miRNA expression are correlated with changes in miRNA transcription. Analysis of leChRO-seq data revealed that transcriptional regulatory elements upregulated in AKP-mutant colonic organoids have an enrichment of predicted binding sites for oncogenic transcription factors.
Project description:To identify direct targets of the environmental sensor AHR, a nuclear transcription factor, in the colonic stem cells, we have performed ChIP sequencing of AHR bound DNA in wildtype colon organoids. ChIP sequencing of AHR knockout organoids was used as a control to filter out non-specific antibody targets.
Project description:Progression of nonmalignant colonic cells harboring somatic mutations depends upon interactions with surrounding stroma; however, details of this interaction are poorly understood. We performed targeted transcriptional profiling of laser-captured epithelial and stromal cells from ACF, the earliest detectable human colonic pre-neoplastic lesion. Within ACF epithelium carrying non-overlapping mutations in KRAS, BRAF, or APC, we observed broad NF-kB-related inflammatory changes and specific differences associated with each mutation, including BRAFV600E-mediated senescence. Additionally, we identified ACF-associated stromal changes indicative of immune cell infiltration and fibroblast activation. Our results provide new insight into intercellular signaling changes that control the earliest stages of CRC development.
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.
Project description:We established human colorectal tumor organoids from benign adenoma, primary colorectal cancer or metastasized colorectal cancer. The gene signature of tumor organoids associated with their tumor progression status. We also generated genome-edited organoids from human intestinal organoids recapitulating adenoma-carcinoma sequence. Gene expression signature of the genome engineered organoids were similar to that of adenoma organoids. This result indicated multiple (up to five) genetic mutations were insufficient for gene expression reprogramming of colorectal cancer. We used microarrays to detail the global program of gene expression in human colorectal tumor organoids and artificially mutation introduced organoids. To assess the expression profiling of genome-engineered organoids, we prepared total-RNA from cultured adenoma, carcinoma and genome-engineered organoids. We produced two types of genome-engineered organoids using the CRISPR/Cas9 or lentivirus vector system. Each engineered gene and engineered methods are described as a single alphabet and method name, respectively, in the sample characteristics field. The abbreviations for the engineered genes are as follows. 1) Genome-engineered organoids with CRISPR/Cas9 A = APC deletion; K = KRAS G12V knock in; S = Smad4 deletion; T = TP53 deletion; P = PIK3CA E545K knock in. 2) Genome-engineered organoids with Lent virus vector B = CTNNB1 S33Y overexpression; K = KRAS G12V overexpression; S = Smad4 shRNA overexpression; T = TP53 shRNA overexpression; P = PIK3CA E545K overexpression.
Project description:We utilized bulk RNA sequencing to assess intrinsic differences between wildtype and autophagy-defective (Atg16l1 deleted) AKPS colorectal cancer organoids in both untreated and IFN gamma treated conditions. AKPS mutations consist of loss-of-function in tumor suppressors Apc, Trp53, Smad4, and gain-of-function in oncogenic Kras(G12D).
Project description:The genomic landscape of colorectal cancer (CRC) is shaped by inactivating mutations in tumour suppressors such as APC, and oncogenic mutations such as mutant KRAS. Here we used genetically engineered mouse models (GEMMs), and multimodal mass spectrometry-based metabolomics to study the impact of common genetic drivers of CRC on the metabolic landscape of the intestine. We show that untargeted metabolic profiling can be applied to stratify intestinal tissues according to underlying genetic alterations, and use mass spectrometry imaging (MSI) to identify tumour, stromal and normal adjacent tissues. By identifying ions that drive variation between normal and transformed tissues, we found dysregulation of the methionine cycle to be a hallmark of APC-deficient CRC. Loss of Apc in the murine intestine was found sufficient to drive expression of one of its enzymes, adenosylhomocysteinase (AHCY), which was also found to be transcriptionally upregulated in human CRC. Targeting of AHCY function impaired growth of APC-deficient organoids in vitro, and prevented the characteristic hyperproliferative/crypt progenitor phenotype driven by acute deletion of Apc in vivo, even in the context of mutant Kras. Finally, pharmacological inhibition of AHCY reduced intestinal tumour burden in ApcMin/+ mice indicating its potential as a metabolic drug target in CRC.
Project description:Mutant KRAS activates cancer stem cells (CSCs) contributing transformation of colorectal cancer (CRC) cells harboring adenomatous polyposis coli (APC) mutations. The factors mediating activation of CSCs by KRAS mutation were systematically investigated through a microarray analysis of the APC-mutated isogenic DLD-1 CRC cells harboring homogeneous wild-type KRAS (D-WT) or mutant KRAS (D-MT). The objective of the study was to find the factors specifically induced in the spheroids harboring both APC and KRAS mutations.