Unknown,Transcriptomics,Genomics,Proteomics

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Progastrin dependent cancer cell proliferation

ABSTRACT: Overexpression of human progastrin (hGAS) in mice has been observed to increase colonic mucosa proliferation significantly, but the mechanism and receptors of progastrin have not been defined. We investigated this mechanism by observing the microarray gene expression in mGAS-/- mice, WT mice, and hGAS transgenic mice. Gene expression of colonic mucosa of WT C57BL/6 mice,Gas-/- C57BL/6 mice, and hGAS transgenic mice, all 6 weeks old were compared.

ORGANISM(S): Mus musculus

SUBMITTER: Timothy Wang

PROVIDER: E-GEOD-28620 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:There is a gradient of M-NM-2-catenin expression along the colonic crypt axis with the highest levels at the crypt bottom. However, it remains unclear whether different levels of canonical Wnt signaling exert distinct roles in the colonic epithelium. In the present study, we first showed that the canonical Wnt signaling is active in the proliferative compartment of normal colonic crypts by separating actively proliferating progenitor cells from non-proliferating cells in the colon using transgenic mice expressing a histone H2B-green fluorescent protein (GFP) fusion protein under the control of a tetracycline responsive regulatory element. Subsequently, we investigated the dose-dependent effect of canonical Wnt activation on colonic epithelial differentiation by controlling the expression levels of stabilized M-NM-2-catenin using a doxycycline-inducible transgenic system in mice. We show that elevated levels of Wnt signaling induce the amplification of Lgr5+ cells, which is accompanied by crypt fission and a reduction in cell proliferation among progenitor cells. In contrast, lower levels of M-NM-2-catenin induction enhanced cell proliferation rates of epithelial progenitors without affecting crypt fission rates. Notably, slow-cycling cells produced by M-NM-2-catenin activation exhibit activation of Notch signaling and the treatment of M-NM-2-catenin expressing mice with a Notch inhibitor turned such slow-cycling cells into actively proliferating cells. Our results indicate that the activation of the canonical Wnt signaling pathway is sufficient for de novo crypt formation, and suggest that different levels of canonical Wnt activations, in cooperation with Notch signaling, establish a hierarchy of slower-cycling stem cells and faster-cycling progenitor cells characteristic for the colonic epithelium. To separate actively proliferating cells from non-proliferating cells in normal colon, we used transgenic mice expressing a histone H2B-GFP fusion protein under the control of a tetracycline responsive regulatory element (H2B-GFP mice). In H2B-GFP mice, all colonic crypt cells exhibited strong nuclear GFP signal 7 days after doxycycline administration. When doxycycline was withdrawn for 2 days after the labeling period, nuclear GFP signal was diluted in proliferating cells whereas non-proliferating cells retained GFP. GFPhigh non-proliferating and GFPlow proliferating epithelial cells were sorted from the isolated crypts by FACS for microarray analysis. In addition, to investigate the effects of acute Wnt activation in colon, we generated doxycycline-inducible M-NM-2-catenin mice. Colonic crypts were isolated from untreated mice and mice fed doxycycline in the drinking water (2.0 mg/ml) for 5 days and subjected to microarray analysis.

Project description:Instability in the composition of gut bacterial communities, referred as dysbiosis, has been associated with important human intestinal disorders such as CrohnM-bM-^@M-^Ys disease and colorectal cancer. Here, we show that dysbiosis coupled to Nod2 or Rip2 deficiency suffices to cause an increased risk for intestinal inflammation and colitis-associated carcinogenesis in mice. Aggravated epithelial lesions and dysplasia upon chemical-induced injury associated with loss of Nod2 or Rip2 can be prevented by antibiotics or anti-IL6R treatment. Nod2-mediated risk for intestinal inflammation and colitis-associated tumorigenesis is communicable through maternally-transmitted microbiota even to wild-type hosts. Disease progression was identified to drive complex NOD2-dependent changes of the colonic-associated microbiota. Reciprocal microbiota transplantation rescues the vulnerability of Nod2-deficient mice to colonic injury. Altogether, our results unveil an unexpected function for NOD2 in shaping a protective assembly of gut microbial communities, providing a rationale for intentional manipulation of genotype-dependent dysbiosis as a causative therapeutic principle in chronic intestinal inflammation. Analysis used RNA extracted from colonic mucosa of untreated, antibiotics-treated or metronidazole-treated C57Bl/6J and Nod2-deficient mice in CAC model. Direct comparisons were performed as follow: C57Bl/6J untreated mice vs Nod2-deficient untreated mice, C57Bl/6J antibiotics-treated mice vs Nod2-deficient antibiotics-treated mice, C57Bl/6J metronidazole-treated mice vs Nod2-deficient metronidazole-treated mice, C57Bl/6J untreated mice vs C57Bl/6J antibiotics-treated mice, C57Bl/6J untreated mice vs C57Bl/6J metronidazole-treated mice, Nod2-deficient untreated mice vs Nod2-deficient antibiotics-treated mice, Nod2-deficient untreated mice vs Nod2-deficient metronidazole-treated mice. Indirect comparisons with control data were made across multiple arrays with raw data pulled from different channels for data analysis.

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Progastrin dependent cancer cell proliferation

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