Project description:Mast cells have been suggested to either promote or suppress tumor progression but the mechanisms underlying these outcomes are unclear. Here, we show that mice with a heterozygous mutation in the adenomatous polyposis coli gene (ApcMin/+) displayed reduced intestinal tumor burden and increased survival in the background of the chemokine decoy receptor ACKR2 deficiency (ACKR2-/-). The ACKR2-/-ApcMin/+ tumors showed increased infiltration of mast cells. In mast cell-deficient Sash (c-kitW-sh/W-sh) ACKR2-/-ApcMin/+ mice the survival advantage was lost as the tumors grew rapidly and adoptive transfer of mast cells reduced the tumor burden in these mice. The tumor burden is also increased in Rag2-/-ACKR2-/-ApcMin/+ mice and the protection is reconstituted by adoptively transferred CD8+ T-lymphocytes. Mast cells from ACKR2-/- mice expressed elevated levels of chemokine receptors CCR2 and CCR5 and are also efficient in antigen presentation and activation of CD8+ T-cells. Mast cell-derived leukotriene B4 is a critical mediator of CD8+ T-lymphocyte recruitment as the BLT1-/-ACKR2-/-ApcMin/+ mice are highly susceptible to intestinal tumor induced mortality. Taken together, these data demonstrate that chemokine mediated mast cell recruitment is essential for initiating LTB4/BLT1 regulated CD8+ T-cell homing and generation of effective anti-tumor immunity against intestinal tumor development.
Project description:Changes in gene expression profile of intestinal (ILEUM) Tumors from APCmin/+/VP16LXRa vs APCmin/+/VP16. The hypothesis tested in the present study was that LXRa overexpression influence cancer growth modulating lipid metabolism in cancer cells. Results provide the information that LXRa induces genes encoding proteins able to regulate cholesterol efflux. Total RNA obtained from Ileum tumors from APCmin/+/VP16LXRa mice was compared to total RNA extracted from APCmin/+/VP16 mice.
Project description:Changes in gene expression profile of intestinal (COLON) Tumors from APCmin/+/VP16LXRa vs APCmin/+/VP16. The hypothesis tested in the present study was that LXRa overexpression influence cancer growth modulating lipid metabolism in cancer cells. Results provide the information that LXRa induces expression of genes encoding proteins able to regulate cholesterol efflux. Total RNA obtained from colonic tumors from APCmin/+/VP16LXRa mice was compared to total RNA extracted from APCmin/+/VP16 mice.
Project description:Changes in gene expression profile of intestinal (ILEUM) Tumors from APCmin/+/VP16LXRa vs APCmin/+/VP16. The hypothesis tested in the present study was that LXRa overexpression influence cancer growth modulating lipid metabolism in cancer cells. Results provide the information that LXRa induces genes encoding proteins able to regulate cholesterol efflux.
Project description:Changes in gene expression profile of intestinal (COLON) Tumors from APCmin/+/VP16LXRa vs APCmin/+/VP16. The hypothesis tested in the present study was that LXRa overexpression influence cancer growth modulating lipid metabolism in cancer cells. Results provide the information that LXRa induces expression of genes encoding proteins able to regulate cholesterol efflux.
Project description:Analysis of metabolic pathway gene expression. The hypothesis tested in the present study is to assess mRNA level changes in metabolic genes in intestinal tumors from APCmin mice overexpressing PGC-1β specifically in the intestine. Total RNA obtained from ileum tumor samples from iPGC-1β/APCmin mice was compared to the total RNA extracted from FVBN/APCmin mice.
Project description:Analysis of metabolic pathway gene expression. The hypothesis tested in the present study is to assess mRNA level changes in metabolic genes in intestinal tumors from APCmin mice overexpressing PGC-1β specifically in the intestine.
Project description:Background and aims: The transcription factor Stat3 has been considered to promote progression and metastasis of intestinal cancers. Methods: We investigated the role of Stat3 in intestinal tumors using mice with conditional ablation of Stat3 in intestinal epithelial cells (Stat3deltaIEC). Results: In the APCmin mouse model of intestinal cancer, genetic ablation of Stat3 reduced the multiplicity of early adenomas. However, loss of Stat3 promoted tumor progression at later stages leading to formation of invasive carcinomas which significantly shortened the lifespan of Stat3deltaIEC APCmin/+ mice. Interestingly, loss of Stat3 in tumors of APCmin/+ mice had no significant impact on cell survival and angiogenesis but promoted cell proliferation. A genome-wide expression analysis of Stat3-deficient tumors suggested that Stat3 negatively regulates intestinal cancer progression via the cell adhesion molecule Ceacam1. Conclusions: Our data suggest that Stat3 impairs progression of intestinal tumors. Therefore, detrimental effects on tumor progression have to be considered upon therapeutic targeting of the Stat3 signaling pathway in intestinal cancer.
Project description:To identify the precise molecular mechanisms that could contribute to the increase in colon carcinogenesis, microarray gene expression analysis was performed on colon RNA isolated from 5-week-old VhlF/F and VhlΔIE, VhlΔIE/Apcmin/+ and VhlF/F/Apcmin/+ mice. Hypoxia-inducible factor (HIF) is a key modulator of the transcriptional response to hypoxia and is increased in colon cancer. However, the role of HIF in colon carcinogenesis in vivo remains unclear. Intestinal epithelium-specific disruption of the von Hippel-Lindau tumor suppressor protein (VHL) resulted in constitutive HIF signaling, and increased HIF expression augmented colon tumorigenesis in the Apcmin/+ intestinal tumor model. Intestine-specific disruption of Vhl increased colon tumor multiplicity and progression from adenomas to carcinomas. These effects were ameliorated in mice with double disruption of Vhl and Hif-2α. Activation of HIF signaling resulted in increased cell survival in normal colon tissue, however tumor apoptosis was not affected. Interestingly, a robust activation of cyclin D1 was observed in tumors of Apcmin/+ mice in which HIF-2α was activated in the intestine. Consistent with this result, BrdU incorporation indicated that cellular proliferation was increased in colon tumors following HIF activation. Further analysis demonstrated that dysregulation of the intestinal iron absorption transporter divalent metal transporter-1 (DMT-1) was a critical event in HIF-2α-mediated colon carcinogenesis. These data provide a mechanistic basis for the widely reported link between iron accumulation and colon cancer risk. Together, our findings demonstrate that a chronic increase in HIF-2α in the colon initiates pro-tumorigenic signaling which may have important implications in developing preventive and therapeutic strategies for colon cancer. Global gene expression profiling in colon RNAs isolated from 5-week-old VhlF/F (n=4, Shah 001), VhlF/F/Apcmin/+(n=3, Shah 003), VhlΔIE (n=3, Shah 002) and VhlΔIE/Apcmin/+ mice (n=5, Shah 004).
Project description:To identify the precise molecular mechanisms that could contribute to the increase in colon carcinogenesis, microarray gene expression analysis was performed on colon RNA isolated from 5-week-old VhlF/F and VhlΔIE, VhlΔIE/Apcmin/+ and VhlF/F/Apcmin/+ mice. Hypoxia-inducible factor (HIF) is a key modulator of the transcriptional response to hypoxia and is increased in colon cancer. However, the role of HIF in colon carcinogenesis in vivo remains unclear. Intestinal epithelium-specific disruption of the von Hippel-Lindau tumor suppressor protein (VHL) resulted in constitutive HIF signaling, and increased HIF expression augmented colon tumorigenesis in the Apcmin/+ intestinal tumor model. Intestine-specific disruption of Vhl increased colon tumor multiplicity and progression from adenomas to carcinomas. These effects were ameliorated in mice with double disruption of Vhl and Hif-2α. Activation of HIF signaling resulted in increased cell survival in normal colon tissue, however tumor apoptosis was not affected. Interestingly, a robust activation of cyclin D1 was observed in tumors of Apcmin/+ mice in which HIF-2α was activated in the intestine. Consistent with this result, BrdU incorporation indicated that cellular proliferation was increased in colon tumors following HIF activation. Further analysis demonstrated that dysregulation of the intestinal iron absorption transporter divalent metal transporter-1 (DMT-1) was a critical event in HIF-2α-mediated colon carcinogenesis. These data provide a mechanistic basis for the widely reported link between iron accumulation and colon cancer risk. Together, our findings demonstrate that a chronic increase in HIF-2α in the colon initiates pro-tumorigenic signaling which may have important implications in developing preventive and therapeutic strategies for colon cancer.