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Project description:Background/aimThe entire mechanisms by which epigenetic modifiers contribute to the development of pancreatic cancer remain unknown. Although the histone methyltransferase G9a is a promising target in human cancers, its role in pancreatic carcinogenesis has been under-studied. The aim of the study was to examine the role of G9a in pancreatic carcinogenesis by a gene-targeting mouse model.Materials and methodsWe established pancreas-specific G9aflox/flox mice and crossed them with Ptf1aCre/; KrasG12D/+ (KC) mice, which spontaneously develop pancreatic cancer. The phenotypes of the resulting KC mice with G9a deletion were examined. We analyzed transcriptomic data by microarray and genome-wide chromatin accessibility by transposase-accessible chromatin using sequencing. We established pancreatic organoids from KC mice.ResultsG9a deficiency impaired the progression of pancreatic intraepithelial neoplasia (PanIN) and prolonged the survival of KC mice. The number of phosphorylated Erk-positive cells and Dclk1-positive cells, which are reported to be essential for the progression of PanIN, were decreased by G9a deletion. UNC0638, an inhibitor of G9a, suppressed the growth of organoids and increased global chromatin accessibility, especially around the regions including the protein phosphatase 2A genes.ConclusionThus, our study suggested the functional interaction of G9a, Dclk1 and Mapk pathway in the Kras-driven pancreatic carcinogenesis. The inhibition of G9a may suppress the initiation of oncogenic Kras-driven pancreatic carcinogenesis.
| S-EPMC7675651 | biostudies-literature
Project description:Histone methyltransferase G9a governs the mutant Kras-driven pancreatic carcinogenesis
| PRJNA635814 | ENA
Project description:To investigate the transcriptomic effects of iASPP deletion or p53 mutation in the KRASG12D background Pdx1-Cre was used to delete iASPP in oncogenic KRASG12D expressing (KC) background to generate KC;iASPPΔ8/Δ8 mice. KC and KC;iASPPΔ8/Δ8 mice were then crossed with mice containing a p53R172H allele (equivalent to human p53 hotspot mutation R175H) to generate KPC and KPC;iASPPΔ8/Δ8 cohorts. Primary cell cultures were then derived from pancreatic ductal adenocarcinoma tissue for RNA-seq.
2023-07-06 | GSE226595 | GEO
Project description:Tumor suppression that is mediated by oncogene-induced senescence (OIS) is considered to function as a safeguard during development of pancreatic ductal adenocarcinoma (PDAC). However, the mechanisms that regulate OIS in PDAC are poorly understood. Here, we have determined that nuclear RelA reinforces OIS to inhibit carcinogenesis in the Kras mouse model of PDAC. Inactivation of RelA accelerated pancreatic lesion formation in Kras mice by abrogating the senescence-associated secretory phenotype (SASP) gene transcription signature. Using genetic and pharmacological tools, we determined that RelA activation promotes OIS via elevation of the SASP factor CXCL1 (also known as KC), which activates CXCR2, during pancreatic carcinogenesis. In Kras mice, pancreas-specific inactivation of CXCR2 prevented OIS and was correlated with increased tumor proliferation and decreased survival. Moreover, reductions in CXCR2 levels were associated with advanced neoplastic lesions in tissue from human pancreatic specimens. Genetically disabling OIS in Kras mice caused RelA to promote tumor proliferation, suggesting a dual role for RelA signaling in pancreatic carcinogenesis. Taken together, our data suggest a pivotal role for RelA in regulating OIS in preneoplastic lesions and implicate the RelA/CXCL1/CXCR2 axis as an essential mechanism of tumor surveillance in PDAC.
| S-EPMC4966329 | biostudies-literature
Project description:Aberrant activation of GLI transcription factors has been implicated in the pathogenesis of different tumor types including pancreatic ductal adenocarcinoma. However, the mechanistic link with established drivers of this disease remains in part elusive. In this study, using a new genetically engineered mouse model overexpressing constitutively active mouse form of GLI2 and a combination of genome-wide assays, we provide evidence of a novel mechanism underlying the interplay between KRAS, a major driver of pancreatic ductal adenocarcinoma development, and GLI2 to control oncogenic gene expression. These mice, also expressing KrasG12D, show significantly reduced median survival rate and accelerated tumorigenesis compared with the KrasG12D only expressing mice. Analysis of the mechanism using RNA sequencing demonstrate higher levels of GLI2 targets, particularly tumor growth-promoting genes, including Ccnd1, N-Myc, and Bcl2, in KrasG12D mutant cells. Furthermore, chromatin immunoprecipitation sequencing studies showed that in these cells KrasG12D increases the levels of trimethylation of lysine 4 of the histone 3 (H3K4me3) at the promoter of GLI2 targets without affecting significantly the levels of other major active chromatin marks. Importantly, Gli2 knockdown reduces H3K4me3 enrichment and gene expression induced by mutant Kras. In summary, we demonstrate that Gli2 plays a significant role in pancreatic carcinogenesis by acting as a downstream effector of KrasG12D to control gene expression.
| S-EPMC11232480 | biostudies-literature
Project description:Pooled KRC (LSL-KrasG12D; Rb1L/L; Pdx1-Cre: oncogenic Kras and deleted Rb1 in the pancreas) cells derived from 2 month old mice were compared to pooled KC (LSL-KrasG12D; Pdx1-Cre: oncogenic Kras in the pancreas) cells derived from 8 month old mice.
2014-02-09 | E-MEXP-3988 | biostudies-arrayexpress
Project description:Inflammatory transcription networks have been linked with the development of pancreatic ductal adenocarcinoma (PDAC). Here, we demonstrate that NFATc1 is both necessary and sufficient to drive progression of KrasG12D-initiated PDAC, particularly in the context of inflammation. Significantly, nuclear NFATc1 accelerates PDAC development in KrasG12D mice, whereas conditional NFATc1 deletion or pharmacological inhibition attenuates inflammation-mediated carcinogenesis. Mechanistically, NFATc1 induces STAT3 expression, complex formation and signal integration in PDAC. Genome-wide ChIP-sequencing and expression analysis in cells derived from c.n.NFATc1;KrasG12D mice identified combinatorial NFATc1/STAT3 binding at chromatin enhancer sites and subsequent regulation of key molecules involved in oncogenic signaling, growth and inflammation. Together, this study supports the relevance of inflammatory transcription factor networks in pancreatic carcinogenesis and provides a theoretical platform for therapeutic targeting of NFATc1 nucleoprotein complexes in PDAC. NFATc1 ChIP followed by high throughput sequencing in primary murine pancreatic cancer cells (referred to as NKC cells) derived from transgenic mice with pancreas-specific constitutive activation of NFATc1 and KrasG12D mutation in the presence or absence of STAT3 shRNA; 2 ChIP samples (scramble DNA and shSTAT3 DNA) and 1 unenriched input control from the same chromatin pool.
2014-06-30 | E-GEOD-39969 | biostudies-arrayexpress
Project description:we reported a high-content drug screening platform of a series of pancreas organoids which contain common mutations found in human pancreatic cancer, wide type (WT), KC (KRASG12D), KPC (KRASG12D; Tp53R172H), KSC (KRASG12D; SMAD4-/-) and KPSC (KRASG12D; Tp53R172H and SMAD4-/-). Based on this platform, we screened about 6000 compounds and identified Perhexiline, which can inhibit the growth of pancreas organoids with KRAS mutation in vitro and in vivo. Single cell RNA-seq data shows that the cholesterol synthesis pathway is activated specifically caused by KRAS in mutated organoid lines. The key cholesterol synthesis regulator of SREBP2 and its downstream genes are activated in KRAS mutated organoids compared with WT. Interestingly, Perhexiline can reverse the metabolism changes in pancreas organoids with KRAS through downregulating SREBP2 at transcription level. Finally, we further validated targeting SREBP2 can attenuate tumor growth significantly with chemical inhibitor and genetic perturbation. These findings boost further understanding of KRAS in PDAC and provide a valuable resource for targeting KRAS therapeutics development.
2023-11-16 | GSE207352 | GEO
Project description:While adult pancreatic stem cells are thought not to exist, it is now appreciated that the acinar compartment harbors progenitors, including tissue-repairing facultative progenitors (FPs). Here, we study a pancreatic acinar population marked by trefoil factor 2 (Tff2) expression. Long-term lineage tracing and single-cell RNA sequencing (scRNA-seq) analysis of Tff2-DTR-CreERT2-targeted cells defines a transit-amplifying progenitor (TAP) population that contributes to normal homeostasis. Following acute and chronic injury, Tff2+ cells, distinct from FPs, undergo depopulation but are eventually replenished. At baseline, oncogenic KrasG12D-targeted Tff2+ cells are resistant to PDAC initiation. However, KrasG12D activation in Tff2+ cells leads to survival and clonal expansion following pancreatitis and a cancer stem/progenitor cell-like state. Selective ablation of Tff2+ cells prior to KrasG12D activation in Mist1+ acinar or Dclk1+ FP cells results in enhanced tumorigenesis, which can be partially rescued by adenoviral Tff2 treatment. Together, Tff2 defines a pancreatic TAP population that protects against Kras-driven carcinogenesis.
| S-EPMC10414754 | biostudies-literature
Project description:ObjectiveDespite advances in the identification of epigenetic alterations in pancreatic cancer, their biological roles in the pathobiology of this dismal neoplasm remain elusive. Here, we aimed to characterise the functional significance of histone lysine methyltransferases (KMTs) and demethylases (KDMs) in pancreatic tumourigenesis.DesignDNA methylation sequencing and gene expression microarrays were employed to investigate CpG methylation and expression patterns of KMTs and KDMs in pancreatic cancer tissues versus normal tissues. Gene expression was assessed in five cohorts of patients by reverse transcription quantitative-PCR. Molecular analysis and functional assays were conducted in genetically modified cell lines. Cellular metabolic rates were measured using an XF24-3 Analyzer, while quantitative evaluation of lipids was performed by liquid chromatography-mass spectrometry (LC-MS) analysis. Subcutaneous xenograft mouse models were used to evaluate pancreatic tumour growth in vivo.ResultsWe define a new antitumorous function of the histone lysine (K)-specific methyltransferase 2D (KMT2D) in pancreatic cancer. KMT2D is transcriptionally repressed in human pancreatic tumours through DNA methylation. Clinically, lower levels of this methyltransferase associate with poor prognosis and significant weight alterations. RNAi-based genetic inactivation of KMT2D promotes tumour growth and results in loss of H3K4me3 mark. In addition, KMT2D inhibition increases aerobic glycolysis and alters the lipidomic profiles of pancreatic cancer cells. Further analysis of this phenomenon identified the glucose transporter SLC2A3 as a mediator of KMT2D-induced changes in cellular, metabolic and proliferative rates.ConclusionTogether our findings define a new tumour suppressor function of KMT2D through the regulation of glucose/fatty acid metabolism in pancreatic cancer.
| S-EPMC6697184 | biostudies-literature