Project description:Cancer stem cells (CSCs) are a minority population of cancer cells that display stem cell-like multipotent and self-renewal properties. They give rise to the bulk of cancer cells with limited replicative potential. In colorectal cancer (CRC), CSCs are marked by expression of the leucine-rich repeat-containing G-protein receptor 5 (Lgr5). Since CSCs display multipotent and self-renewal properties, this population is thought to seed metastases. Here, we used a mouse model and human xenografts to investigate the cell-of-origin of metastases. Surprisingly, we found that most CRC cells that disseminated and entered the blood circulation were Lgr5-. Lgr5- cancer cells arriving at the metastatic site formed lesions in which Lgr5+ CSCs appeared. This plasticity could occur independently of stemness-inducing factors, and was an indispensable event for the outgrowth of metastases, since neutralization of this plasticity prevented metastatic outgrowth. Combined, our study shows that most metastases are seeded by Lgr5- cancer cells, and that these cells have a niche-independent and intrinsic capacity to become CSCs and restore epithelial hierarchy.
Project description:To further elucidate the role of the intestinal stem cell marker Leucine-rich-repeat-containing G-protein-coupled receptor 5 (LGR5) in colorectal cancer (CRC), we exposed Lgr5-EGFP-IRES-Cre-ERT2 mice to azoxymethane/dextrane sodium sulfate (AOM/DSS) which induces inflammation-driven colon tumors. Tumors were then flow-sorted into fractions of epithelial cells that expressed high or low levels of Lgr5 and were characterized using gene expression profiling. In the AOM/DSS-induced mouse colon tumors Lgr5 high cells showed higher levels of several stem cell-associated genes and higher Wnt signaling than Lgr5 low tumor cells and Lgr5 high normal colon epithelial cells. To further elucidate the role of the intestinal stem cell marker Leucine-rich-repeat-containing G-protein-coupled receptor 5 (LGR5) in colorectal cancer (CRC), we transduced SW480 CRC cells with lentiviral shRNA constructs to silence LGR5 expression. This resulted in a depletion of spheres but did not affect adherently growing cells. Spheres expressed higher levels of several stem cell-associated genes than adherent cells. Notch signaling was down-regulated upon LGR5 silencing. This was confirmed by immunohistochemistry against cleaved NOTCH1. Normal mouse colons and AOM/DSS-induced mouse colon tumors were flow-sorted into Lgr5 high and low cells before gene expression was measured. Fifteen independent experiments were performed using seven individual mice for normal colons and eight for tumors. Appropriate LGR5 status was confirmed by real-time qRT-PCR before measuring silencing induced gene expression. Three independent experiments were performed for each cell fraction using separately cultured cells for each experiment.
Project description:Colorectal cancer tumors are composed of heterogeneous and plastic cell populations, including a pool of cancer stem cells that express LGR5. Whether these distinct cell populations display different mechanical properties, and how these properties might contribute to metastasis is unknown. Using CRC patient derived organoids (PDOs), we found that compared to LGR5- cells, LGR5+ cancer stem cells are stiffer, adhere better to the extracellular matrix (ECM), move slower both as single cells and clusters, display higher nuclear YAP, show a higher survival rate in response to mechanical confinement, and form larger transendothelial gaps. These differences are largely explained by the downregulation of the membrane to cortex attachment proteins Ezrin/Radixin/Moesin (ERMs) in the LGR5+ cells. By analyzing scRNA-seq expression patterns from a patient cohort, we show that this downregulation is a robust signature of colorectal tumors. Our results show that LGR5- cells display a mechanically dynamic phenotype suitable for dissemination from the primary tumor whereas LGR5+ cells display a mechanically stable and resilient phenotype suitable for extravasation and metastatic growth.
Project description:To further elucidate the role of the intestinal stem cell marker Leucine-rich-repeat-containing G-protein-coupled receptor 5 (LGR5) in colorectal cancer (CRC), we exposed Lgr5-EGFP-IRES-Cre-ERT2 mice to azoxymethane/dextrane sodium sulfate (AOM/DSS) which induces inflammation-driven colon tumors. Tumors were then flow-sorted into fractions of epithelial cells that expressed high or low levels of Lgr5 and were characterized using gene expression profiling. In the AOM/DSS-induced mouse colon tumors Lgr5 high cells showed higher levels of several stem cell-associated genes and higher Wnt signaling than Lgr5 low tumor cells and Lgr5 high normal colon epithelial cells. To further elucidate the role of the intestinal stem cell marker Leucine-rich-repeat-containing G-protein-coupled receptor 5 (LGR5) in colorectal cancer (CRC), we transduced SW480 CRC cells with lentiviral shRNA constructs to silence LGR5 expression. This resulted in a depletion of spheres but did not affect adherently growing cells. Spheres expressed higher levels of several stem cell-associated genes than adherent cells. Notch signaling was down-regulated upon LGR5 silencing. This was confirmed by immunohistochemistry against cleaved NOTCH1.
Project description:Lgr5-EGFP-IRES-Cre-ERT2 mice were exposed to azoxymethane/dextrane sodium sulfate (AOM/DSS) which induces inflammation-driven colon tumors. Tumors were then flow-sorted into fractions of epithelial cells that expressed high or low levels of Lgr5. To exclude that transcriptional differences between Lgr5 high and low mouse colon tumor cells were imposed by distinct patterns of chromosomal aberrations in the two cell fractions, we also performed array comparative genomic hybridization (aCGH) from these tumors. All eight analyzed tumors were chromosomally stable, and thus, no difference between Lgr5 high and low cells could be detected. AOM/DSS-induced mouse colon tumors were flow-sorted into Lgr5 high and low cells before aCGH was performed. Biological replicates: 8. Two CGH array platforms.
Project description:Colorectal cancer (CRC) is the third most common and second most deadly cancer worldwide. Treatments for metastatic CRC (mCRC) are still largely based on toxic chemotherapy regimens, but important insights into tumor biology enabled the development of targeted cancer therapies. Here, we describe a proteogenomic analysis of CRC liver metastases (metastatic CRC, mCRC), an ideal setting to analyze therapeutic resistance which occurs in a short time frame. We selected liver metastases from two CRC patients on both of which we performed deep proteome profiling and WES and RNAseq-directed database searches, identifying 10 predicted muttaions, one of which was KRAS G12V. finding we generated targeted parallel reaction monitoring (PRM) assays using stable isotope labelled standard (SIS) peptides to quantify the actual concentration (fmol per µg of total protein) of the mutated and canonical (wildtype) protein variants for 8 different mutations. We demonstrate on a total of 8 tumor and 6 paired healthy tissue samples (7 and 6 out of these KRASG12V) that PRM allows quantifying the actual mutation rate on the protein level from as little 10 µg of total protein starting amount and within a single 1 hour nano-LC-MS/MS run.
Project description:Lgr5-EGFP-IRES-Cre-ERT2 mice were exposed to azoxymethane/dextrane sodium sulfate (AOM/DSS) which induces inflammation-driven colon tumors. Tumors were then flow-sorted into fractions of epithelial cells that expressed high or low levels of Lgr5. To exclude that transcriptional differences between Lgr5 high and low mouse colon tumor cells were imposed by distinct patterns of chromosomal aberrations in the two cell fractions, we also performed array comparative genomic hybridization (aCGH) from these tumors. All eight analyzed tumors were chromosomally stable, and thus, no difference between Lgr5 high and low cells could be detected.
Project description:Cancer cells and fibroblasts from 6 metastases obtained from 5 different patients were submitted to single-cell sequencing on the 10xGenomics platform. These data revealed different subpopulations of cancer-associated fibroblasts (CAF) and their ligand-receptor interactions with cancer cells.
Project description:This study has two components: (1) Human colon adenoma organoids (n=4 patients) were dissociated into single cells. Cells were incubated with a magnetic bead bound to an LGR5 antibody and run through a magnetic column. Magnet bound cells and flow through negative (FTN) cells were obtained. Magnet bound and FTN cells were incubated with an APC-check reagent (which binds to the magnetic bead on the LGR5 antibody) and DAPI, before being sorted by flow cytometry. 3 populations of live (DAPI-) cells were collected: FTN: Flow through negative. LGR5 negative by magnet and by flow cytometry SortedNeg: Magnet bound cells that were negative for LGR5 by flow cytometry SortedPos: Magnet bound cells that were positive for LGR5 by flow cytometry (2) Human colon organoids, as well as the tissue the organoid was derived from and adjcacent normal tissue (from n=19) were also profiled for known colorectal cancer associated mutations using the Qiagen Qiaseq Colorectal Cancer Panel, which provides targeted sequencing information for 71 genes.
Project description:Here we analyze the transcriptional profiles of liver metastases formed by sgCtrl versus sgITPR3 SW480 colorectal cancer cells. We find downregulated genes in sgITPR3 SW480 metastases to be enriched for pathways related to immune response and non-canonical NFkB signaling.