Abstract: Colonic cancers with a serrated morphology have been proposed to comprise a molecularly distinct tumor entity following an alternative pathway of genetic alterations independently of APC mutations. Here we demonstrate that intestinal cell specific expression of oncogenic K-rasG12D in mice induces serrated hyperplasia, which is characterized by p16ink4a overexpression and induction of senescence. Deletion of Ink4a/Arf in K-rasG12D expressing mice prevents senescence and leads to invasive, metastasizing carcinomas with morphological and molecular alterations comparable to human KRAS mutated serrated tumors. Thus, we suggest that oncogenic K-ras is sufficient to initiate an alternative, serrated pathway to colorectal cancer and hence propose RAS-RAF-MEK signaling apart from APC as an additional gatekeeper in colorectal tumor development.
Ink4a/Arf and oncogene-induced senescence prevent tumor progression during alternative colorectal tumorigenesis.
Specimen part
View SamplesGastric cancer can be divided in two major histological subtypes: diffuse and intestinal-type adenocarcinomas. Since both types diverge in many clinical and molecular characteristics, is widely accepted that both represent distinct disease entities that may benefit from different therapeutic approaches. The diffuse type is explicitly more invasive and affected patients possess extremely poor prognosis. Gene expression profiling studies identified numerous genes with differences in mRNA expression between the two types. However, little overlap of published gene lists exists forcing the need for further and more comprehensive analyses.
THBS4, a novel stromal molecule of diffuse-type gastric adenocarcinomas, identified by transcriptome-wide expression profiling.
No sample metadata fields
View SamplesIschemia exists in many diseased tissues including arthritic joints, atherosclerotic plaques and malignant tumors. Macrophages accumulate in these sites and upregulate genes in response to the hypoxia present.
Hypoxia-inducible factors 1 and 2 are important transcriptional effectors in primary macrophages experiencing hypoxia.
Specimen part
View SamplesCombined transcriptomic and functional analyses of HCC cells at single-cell level were performed to assess CSC heterogeneity. Overall design: Single-cell transcriptome analyses of two HCC cell lines (HuH-1 and HuH-7) and one patient-derived circulating tumor cells by using SMART-Seq protocol ***Due to patient privacy concerns, the submitter declares that patient data will be submitted to dbGaP.***
Single-cell analysis reveals cancer stem cell heterogeneity in hepatocellular carcinoma.
Specimen part, Cell line, Subject
View SamplesTo uncover molecular mechanisms specifically involved in the pathogenesis of colitis-associated colon cancer (CAC), we studied tumorigenesis in experimental models of CAC and sporadic CRC that mimic characteristics of human CRC. Using comparative whole genome expression profiling, we observed differential expression of epiregulin (Ereg) in mouse models of colitis-associated, but not sporadic colorectal cancer. Similarly, highly significant upregulation of Ereg expression was found in cohorts of patients with colitis-associated cancer in inflammatory bowel disease but not in sporadic colorectal cancer. Furthermore, tumor-associated fibroblasts were identified as major source of Ereg in colitis-associated neoplasias. Functional studies showed that Ereg-deficient mice, although more prone to colitis, are strongly protected from colitis-associated tumors, and data from serial endoscopic studies revealed that Ereg promotes growth rather than initiation of tumors.
Tumor fibroblast-derived epiregulin promotes growth of colitis-associated neoplasms through ERK.
Sex, Specimen part
View SamplesHere, we examined the role of intestinal epithelial specific tumor suppressive function of 53. We provide evidence that p53 plays a dual role during carcinogen-induced tumorigenesis. At the initiation stage, p53 controls DNA damage and survival of initiated epithelia. In contrast, at later stages, loss of p53 is associated with the formation of an inflammatory microenvironment that is linked to epithelial mesenchymal transition, invasion and metastasis and the activation of NF-kappaB and Stat3. Thus, we propose a novel p53 controlled tumor suppressive function during the progression stage of colorectal cancer that is independent of its well-established role in cell cycle regulation, apoptosis and senescence.
Loss of p53 in enterocytes generates an inflammatory microenvironment enabling invasion and lymph node metastasis of carcinogen-induced colorectal tumors.
Specimen part
View SamplesRecent studies have suggested increased plasticity of differentiated cells within the intestine to act both as intestinal stem cells and tumour initiating cells. However, little is known of the processes that regulate this plasticity. Our previous work has shown that activating mutations of Kras or the NF-kB pathway can drive dedifferentiation of intestinal cells lacking Apc.
TGFβ pathway limits dedifferentiation following WNT and MAPK pathway activation to suppress intestinal tumourigenesis.
Specimen part
View SamplesRecent studies have suggested increased plasticity of differentiated cells within the intestine to act both as intestinal stem cells and tumour initiating cells. However, little is known of the processes that regulate this plasticity. Our previous work has shown that activating mutations of Kras or the NF-kB pathway can drive dedifferentiation of intestinal cells lacking Apc.
TGFβ pathway limits dedifferentiation following WNT and MAPK pathway activation to suppress intestinal tumourigenesis.
No sample metadata fields
View SamplesHepatocellular carcinoma (HCC) is the second most common cause of cancer related death. NAFLD affects a large proportion of the US population. Its incidence and prevalence are increasing to epidemic proportions around the world and is known to increase the risk of HCC. We studied how intrahepatic lipids affect adaptive immunity and HCC development in different murine models of NASH and HCC. Linoleic acid, a fatty acid found in NAFLD caused a selective loss of hepatic CD4+ but not CD8+ T cells leading to accelerated hepatocarcinogenesis. CD4+ T cells were more dependent on oxidative phosphorylation for energy source than CD8+ T cells, and disruption of oxidative phosphorylation by linoleic acid caused more severe damage in CD4+ T cells leading to selective loss of these cells. In vivo blockade of ROS using n-acetylcysteine reversed the NASH-induced hepatic CD4+ T cell decrease and delayed NASH-promoted HCC. Our results provide a new link between lipid metabolism and impaired anti-tumor surveillance.
NAFLD causes selective CD4(+) T lymphocyte loss and promotes hepatocarcinogenesis.
No sample metadata fields
View SamplesDepending on the tumor type IB kinase (IKK) can act as tumor promoter or tumor suppressor in various malignancies. Here we demonstrate a key function of IKK in the suppression of a tumoricidal microenvironment during intestinal carcinogenesis. Mice deficient in IKK kinase activity are largely protected from intestinal tumor development that is dependent on the enhanced recruitment of IFN expressing M1-like myeloid cells. In IKK mutant mice M1-like polarization is not controlled in a cell autonomous manner but depends rather on the interplay of both IKK mutant tumor epithelia and immune cells.
IKKα promotes intestinal tumorigenesis by limiting recruitment of M1-like polarized myeloid cells.
Specimen part, Time
View Samples