ABSTRACT: Kras-induced ikk2/nf-kappaB activation by IL-1 alpha and p62 freedforward loops is required for development of pancreatic ductal adenocarcinoma
Project description:Constitutive Kras and NF-kappaB activation is identified as signature alterations in human pancreatic ductal adenocarcinoma (PDAC). However, the mechanisms of constitutive NF-kappaB activation in KrasG12D-induced PDAC are not yet understood. Here, we report that pancreas-targeted IKK2/beta inactivation inhibited NF-kappaB activation and completely suppressed PDAC development in KrasG12D and KrasG12D;Ink4a/Arf mutant mice, demonstrating a genetic link between IKK2/beta and KrasG12D in PDAC inception. Our findings reveal that KrasG12D-activated AP-1 induces IL-1alpha, which in turn activates NF-kappaB and its target genes IL-1alpha and p62, to initiate IL-1alpha/p62 feedforward loops for inducing and sustaining NF-kappaB activity. Furthermore, IL-1alpha overexpression correlates with Kras mutation, constitutive NF-kappaB activity, and poor survival in PDAC patients. Therefore, our findings establish a pathway linking duel feedforward loops of IL-1alpha/p62 through which IKK2/beta/NF-kappaB is activated by KrasG12D. To study Kras-induced inflammatory responses and to identify differentially expressed genes between the pancreatic tissues of Pdx1-Cre;KrasLSL-G12D and Pdx1-Cre;KrasLSL-G12D;IKK2/betaF/F mice, cDNA microarray analysis was performed.
Project description:Constitutive Kras and NF-kappaB activation is identified as signature alterations in human pancreatic ductal adenocarcinoma (PDAC). However, the mechanisms of constitutive NF-kappaB activation in KrasG12D-induced PDAC are not yet understood. Here, we report that pancreas-targeted IKK2/beta inactivation inhibited NF-kappaB activation and completely suppressed PDAC development in KrasG12D and KrasG12D;Ink4a/Arf mutant mice, demonstrating a genetic link between IKK2/beta and KrasG12D in PDAC inception. Our findings reveal that KrasG12D-activated AP-1 induces IL-1alpha, which in turn activates NF-kappaB and its target genes IL-1alpha and p62, to initiate IL-1alpha/p62 feedforward loops for inducing and sustaining NF-kappaB activity. Furthermore, IL-1alpha overexpression correlates with Kras mutation, constitutive NF-kappaB activity, and poor survival in PDAC patients. Therefore, our findings establish a pathway linking duel feedforward loops of IL-1alpha/p62 through which IKK2/beta/NF-kappaB is activated by KrasG12D.
Project description:Constitutive Kras and NF-kB activation is identified as signature alterations in human pancreatic ductal adenocarcinoma (PDAC). Here, we report that pancreas-targeted IKK2/beta inactivation inhibited NF-kB activation and completely suppressed PDAC development. Our findings demonstrated that NF-kB is required for development of pancreatic ductal adenocarcinoma that was initiated by Kras activation.
Project description:Constitutive Kras and NF-kB activation is identified as signature alterations in human pancreatic ductal adenocarcinoma (PDAC). Here, we report that pancreas-targeted IKK2/beta inactivation inhibited NF-kB activation and completely suppressed PDAC development. Our findings demonstrated that NF-kB is required for development of pancreatic ductal adenocarcinoma that was initiated by Kras activation. Pancreatic tissue from 4 groups of mice were used in this project: (1) the pancreas normal appearance of Pdx1-cre;KrasLSL-G12D;IKK2/beta mice, (2) the normal pancreas of Pdx1-cre;KrasLSL-G12D mice, (3) the pancreatic lesion of pancreatic intraepithelial neoplasia (PanIN) of Pdx1-cre;KrasLSL-G12D mice, and (4) the pancreatic lesion of PDAC of Pdx1-cre;KrasLSL-G12D mice. Each group included three mice. RNA samples from mouse pancreas were hybridized on GeneChip Mouse Gene 1.0 ST arrays (Affymetrix). Group (1) and group (2) were compared, and group (2), group (3) and group (4) were compared.
Project description:We have carried out transcriptional profile analysis in WT MICE and bitransgenic Pdx1-cre/Kras*A MICE baring Pancreatic Ductal Adenocarcinoma Mouse models faithfully simulating human cancer are valuable for genetic identification of potential drug-targets but, among them, the most advantageous for practical use in subsequent preclinical testing of candidate therapeutic regimes are those exhibiting rapid tumor development. Considering that a KRAS mutation (predominantly in codon 12, such as KRASG12D; KRAS*) occurs with high frequency (~90%) in cases of human pancreatic ductal adenocarcinoma (PDA)1, we sought to develop a mouse PDA model that would exhibit high tumor incidence and short latency by ectopic overexpression of Kras*. Five WT mice and 6 bitransgenic Pdx1-cre/Kras*A MICE baring Pancreatic Ductal Adenocarcinoma were used to identify key genes in the formation of panceatic malignacies
Project description:Pancreatic ductal adenocarcinoma (PDAC) is strikingly resistant to conventional approaches. In this study, we report that the histone deacetylase associated SIN3B protein is required for activated KRAS-induced senescence in vivo using a mouse model of pancreatic cancer. We used microarray data to determine if SIN3B regulates KRAS-induced expression of the inflammatory response. Total RNA from Sin3Bp+/-KRaspG12D and Sin3Bp-/-KRaspG12D pancreas (two pancreata for each genotype) or PDEC (one for each genotype) was extracted and hybridized on Affymtrix microarrays.
Project description:Pancreatic ductal adenocarcinoma (PDAC) is strikingly resistant to conventional approaches. In this study, we report that the histone deacetylase associated SIN3B protein is required for activated KRAS-induced senescence in vivo using a mouse model of pancreatic cancer. We used microarray data to determine if SIN3B regulates KRAS-induced expression of the inflammatory response.
Project description:Unraveling the complexity of transcriptional programs coded by different cell types has been one of the central goals of cell biology. Using genome-wide location analysis, we examined how two different cell types generate different responses to the NF-kappaB signaling pathway. We showed that, after tumor necrosis factor-alpha (TNF-alpha) treatment, NF-kappaB p65 subunit binds to distinct genome locations and subsequently induces different subsets of genes in human monocytic THP-1 cells versus HeLa cells . Interestingly, the differential p65 binding in two cell types correlates with pre-existing cell-type specific enhancers prior to TNF-alpha stimulation, marked by histone modifications. We also found that two transcription factors, PU.1 and C/EBPalpha, appear to synergistically mediate enhancer creation and affect NF-kappaB target selection in THP-1 cells. In HeLa cells, co-expression of PU.1 and C/EBPalpha conferred TNF-alpha responsiveness to a subset of THP-1 specific NF-kappaB target genes. These results suggest that the diversity of transcriptional programs in mammalian cells arises, at least in part, from pre-existing enhancers that are established by cell specific transcription factors. We used Affymetrix microarray (GPL570) to obtain gene expression data for THP1 and HeLa cells before and after TNF-alpha treatment.
Project description:Unraveling the complexity of transcriptional programs coded by different cell types has been one of the central goals of cell biology. Using genome-wide location analysis, we examined how two different cell types generate different responses to the NF-kappaB signaling pathway. We showed that, after tumor necrosis factor-alpha (TNF-alpha) treatment, NF-kappaB p65 subunit binds to distinct genome locations and subsequently induces different subsets of genes in human monocytic THP-1 cells versus HeLa cells . Interestingly, the differential p65 binding in two cell types correlates with pre-existing cell-type specific enhancers prior to TNF-alpha stimulation, marked by histone modifications. We also found that two transcription factors, PU.1 and C/EBPalpha, appear to synergistically mediate enhancer creation and affect NF-kappaB target selection in THP-1 cells. In HeLa cells, co-expression of PU.1 and C/EBPalpha conferred TNF-alpha responsiveness to a subset of THP-1 specific NF-kappaB target genes. These results suggest that the diversity of transcriptional programs in mammalian cells arises, at least in part, from pre-existing enhancers that are established by cell-specific transcription factors.
