Epithelial aPKC deficiency leads to stem cell loss preceding metaplasia in colorectal cancer initiation [RNA-Seq]
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ABSTRACT: The early mechanisms of spontaneous tumor initiation that precede the accumulation of cancer mutations are largely unknown. We show that reduced aPKC levels correlate with stem cell loss and the induction of revival and metaplastic programs in serrated- and conventional-initiated pre-neoplastic lesions, which is perpetuated in colorectal cancers (CRC). Acute inactivation of PKCl/i in vivo and in organoids is sufficient to stimulate JNK in non-transformed intestinal epithelial cells (IECs), which promotes cell death and the rapid loss of the intestinal stem cells (ISC), including LGR5+ cells. This is followed by the accumulation of revival stem cells (RSC) at the bottom of the crypt and fetal metaplastic cells (FMC) at the top, creating two spatiotemporally distinct cell populations that depend on JNK-induced AP-1 and YAP. These cell lineage changes are maintained during cancer initiation and progression and determine the aggressive phenotype of human CRC irrespective of their serrated or conventional origin
Project description:The early mechanisms of spontaneous tumor initiation that precede the accumulation of cancer mutations are largely unknown. We show that reduced aPKC levels correlate with stem cell loss and the induction of revival and metaplastic programs in serrated- and conventional-initiated pre-neoplastic lesions, which is perpetuated in colorectal cancers (CRC). Acute inactivation of PKCl/i in vivo and in organoids is sufficient to stimulate JNK in non-transformed intestinal epithelial cells (IECs), which promotes cell death and the rapid loss of the intestinal stem cells (ISC), including LGR5+ cells. This is followed by the accumulation of revival stem cells (RSC) at the bottom of the crypt and fetal metaplastic cells (FMC) at the top, creating two spatiotemporally distinct cell populations that depend on JNK-induced AP-1 and YAP. These cell lineage changes are maintained during cancer initiation and progression and determine the aggressive phenotype of human CRC irrespective of their serrated or conventional origin
Project description:The early mechanisms of spontaneous tumor initiation that precede the accumulation of cancer mutations are largely unknown. We show that reduced aPKC levels correlate with stem cell loss and the induction of revival and metaplastic programs in serrated- and conventional-initiated pre-neoplastic lesions, which is perpetuated in colorectal cancers (CRC). Acute inactivation of PKCl/i in vivo and in organoids is sufficient to stimulate JNK in non-transformed intestinal epithelial cells (IECs), which promotes cell death and the rapid loss of the intestinal stem cells (ISC), including LGR5+ cells. This is followed by the accumulation of revival stem cells (RSC) at the bottom of the crypt and fetal metaplastic cells (FMC) at the top, creating two spatiotemporally distinct cell populations that depend on JNK-induced AP-1 and YAP. These cell lineage changes are maintained during cancer initiation and progression and determine the aggressive phenotype of human CRC irrespective of their serrated or conventional origin
Project description:The serrated adenocarcinoma subtype accounts for 15-30% of all colorectal cancers (CRCs) and is aggressive and treatment-resistant. it is an alternative mechanism for CRC development characterized by dysregulation of the MAPK pathway. We show that human serrated tumors display reduced expression of PKCz and PKCl/i, and that the simultaneous inactivation of these genes in the mouse intestinal epithelium resulted in spontaneous tumorigenesis through the serrated pathway that progressed to advanced cancer. Whereas epithelial PKCl/i deficiency led to immunogenic cell death that repressed tumor initiation, interferon and CD8+ T cell responses were impaired concomitant with stromal activation and immunosuppression driven by PKCz loss. Thus, PKCz and PKCl/i cooperatively suppress serrated tumorigenesis. Targeting this stromal activation and immunosuppression showed synergistic curative activity.
Project description:Serrated adenocarcinomas are morphologically different from conventional adenocarcinomas. The serrated pathway has recently been proposed to represent a novel mechanism of colorectal cancer (CRC) formation. However, whether they are biologically different and truly form a distinct subclass of CRC, is not known. This study shows that the gene expression profile of serrated and conventional CRCs differs from each others and that serrated CRCs are not only morphologically novel, but also biologically distinct subclass of CRC. Keywords: molecular classification
Project description:Serrated adenocarcinomas are morphologically different from conventional adenocarcinomas. The serrated pathway has recently been proposed to represent a novel mechanism of colorectal cancer (CRC) formation. However, whether they are biologically different and truly form a distinct subclass of CRC, is not known. This study shows that the gene expression profile of serrated and conventional CRCs differs from each others and that serrated CRCs are not only morphologically novel, but also biologically distinct subclass of CRC. Experiment Overall Design: Total RNA was extracted from fresh frozen tumors with Trizol (GibcoBRL) and purified using RNeasy spin columns (Qiagen). The RNA quality was analyzed using a spectrophotometer and a Agilent 2100 Bioanalyzer (Agilent Technologies). Biotin labeled and fragmented cRNA was prepared from 8 micrograms of total RNA with procedures recommended for the HG-U133 GeneChip expression analysis (Affymetrix). The HG-U133A chips were hybridized, scanned and analyzed with Microarray Suite 5.0 software according to the manufacturerâ??s instructions (Affymetrix).
Project description:We noticed that a recently identified poor prognosis stem/serrated molecular subtype of colorectal cancer (CRC) is characterized by up-regulation of transcripts known to be also expressed by stromal cells. To better define the origin of such transcripts, we analyzed RNAseq and microarray datasets from CRC mouse xenografts, where human cancer cells are supported by murine stroma. The analysis revealed that mRNA levels of stem/serrated subtype genes are mostly due to stromal expression, even when the stromal fraction is below 5%. Indeed, a classifier based on genes exclusively expressed by cancer-associated fibroblasts was significantly associated, in multiple datasets, to poor prognosis of CRC and to radioresistance of rectal cancer. Tumor Matched with Corresponding PDX
Project description:We noticed that a recently identified poor prognosis stem/serrated molecular subtype of colorectal cancer (CRC) is characterized by up-regulation of transcripts known to be also expressed by stromal cells. To better define the origin of such transcripts, we analyzed RNAseq and microarray datasets from CRC mouse xenografts, where human cancer cells are supported by murine stroma. The analysis revealed that mRNA levels of stem/serrated subtype genes are mostly due to stromal expression, even when the stromal fraction is below 5%. Indeed, a classifier based on genes exclusively expressed by cancer-associated fibroblasts was significantly associated, in multiple datasets, to poor prognosis of CRC and to radioresistance of rectal cancer. Molecular Characterization of 72 primary rectal cancer formalin-fixed, paraffin-embedded (FFPE) specimens including 58 pretreatment specimens, 14 surgical specimens.
Project description:This study was conducted to explore the serum methylome of precancerous lesions belonging to the serrated pathway of colorectal carcinogenesis in a prospective multicentre cohort. Individuals were grouped into five main categories: (i) serrated adenocarcinoma (SAC), (ii) high-risk serrated polyps (HR-SP) comprising traditional serrated adenomas (TSA), sessile serrated lesions (SSL), and serrated polyps (SP) with dysplasia or ≥ 10 mm; (iii) high-risk hyperplastic polyps (HR-HP), defined as HP ≥ 10 mm; (iv) low-risk serrated lesions (LR-SL) including SP without dysplasia < 10 mm and HP < 10 mm; and (v) healthy individuals with no colorectal findings (NCF). First, epigenome-wide methylation levels were quantified in pooled cfDNA samples to characterize the differential methylation profile between no serrated neoplasia (NSN: NCF and LR-SL) and high-risk serrated lesions (HR-SL: HR-HP and HR-SP); concordance with tissue methylation levels was assessed using external datasets. Then, the pathway-specific cfDNA methylation signature was evaluated together with cfDNA pools from the conventional CRC pathway. cfDNA was extracted from serum samples and methylation measurements were assessed with the Infinium MethylationEPIC BeadChip. Data was mainly preprocessed and analyzed with R/Bioconductor packages.
Project description:The serrated adenocarcinoma subtype accounts for 15-30% of all colorectal cancers (CRCs) and is aggressive and treatment-resistant. it is an alternative mechanism for CRC development characterized by dysregulation of the MAPK pathway. We show that human serrated tumors display reduced expression of PKCz and PKCl/i, and that the simultaneous inactivation of these genes in the mouse intestinal epithelium resulted in spontaneous tumorigenesis through the serrated pathway that progressed to advanced cancer. Whereas epithelial PKCl/i deficiency led to immunogenic cell death that repressed tumor initiation, interferon and CD8+ T cell responses were impaired concomitant with stromal activation and immunosuppression driven by PKCz loss. Thus, PKCz and PKCl/i cooperatively suppress serrated tumorigenesis. Targeting this stromal activation and immunosuppression showed synergistic curative activity.
Project description:We noticed that a recently identified poor prognosis stem/serrated molecular subtype of colorectal cancer (CRC) is characterized by up-regulation of transcripts known to be also expressed by stromal cells. To better define the origin of such transcripts, we analyzed RNAseq and microarray datasets from CRC mouse xenografts, where human cancer cells are supported by murine stroma. The analysis revealed that mRNA levels of stem/serrated subtype genes are mostly due to stromal expression, even when the stromal fraction is below 5%. Indeed, a classifier based on genes exclusively expressed by cancer-associated fibroblasts was significantly associated, in multiple datasets, to poor prognosis of CRC and to radioresistance of rectal cancer.