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The chromatin protein Nupr1 regulates RelB-dependent NF-kB events necessary for pancreatic cancer development

ABSTRACT: The objective of this study was to elucidate the role of Nupr1 in pancreatic tumorigenesis. Using the Pdx-1-cre;LSL-KrasG12D mouse as model we discovered that, in contrast to KrasG12D pancreas that develop multiple foci of pancreatic intraepithelial neoplasia (PanIN), KrasG12D;Nupr1KO pancreas were free from such lesions, indicating that Nupr1 is pivotal for PanIN formation. In vitro, MiaPaCa2 cells activated Nupr1 expression in response to nutrient deprivation and this expression was necessary for cell survival. Mechanistically, Nupr1 protected cells from stress-induced death by inhibiting apoptosis through an alternative RelBàIER3-dependent pathway and independent from activation of the classical RelA-based NF-kB pathway. In agreement with these findings, Nupr1, RelB and IER3 proteins were found co-expressed in PanINs from KrasG12D pancreas. Moreover, pancreas-specific KrasG12D;RelbDpanc mice displayed a delay in PanIN development associated with a lack of IER3 expression, further emphasizing the relevance of this pathway in vivo. Efficient PanIN formation was therefore dependent on the expression of Nupr1 and RelB, with the probable involvement of IER3. Finally, a significant correlation between expression of Nupr1, RelB and IER3 and a poor prognosis of patients with PDAC was found. Altogether, our results reveal a novel stress-related pathway that requires the functional interaction of Nupr1àRelBàIER3 in KrasG12D-dependent transformation of the pancreas and expand our understanding of the molecular machinery that mediates the early steps of pancreatic carcinogenesis.

ORGANISM(S): Homo sapiens

PROVIDER: GSE35463 | GEO | 2012/02/01

SECONDARY ACCESSION(S): PRJNA152337

REPOSITORIES: GEO

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Project description:The objective of this study was to elucidate the role of Nupr1 in pancreatic tumorigenesis. Using the Pdx-1-cre;LSL-KrasG12D mouse as model we discovered that, in contrast to KrasG12D pancreas that develop multiple foci of pancreatic intraepithelial neoplasia (PanIN), KrasG12D;Nupr1KO pancreas were free from such lesions, indicating that Nupr1 is pivotal for PanIN formation. In vitro, MiaPaCa2 cells activated Nupr1 expression in response to nutrient deprivation and this expression was necessary for cell survival. Mechanistically, Nupr1 protected cells from stress-induced death by inhibiting apoptosis through an alternative RelBàIER3-dependent pathway and independent from activation of the classical RelA-based NF-kB pathway. In agreement with these findings, Nupr1, RelB and IER3 proteins were found co-expressed in PanINs from KrasG12D pancreas. Moreover, pancreas-specific KrasG12D;RelbDpanc mice displayed a delay in PanIN development associated with a lack of IER3 expression, further emphasizing the relevance of this pathway in vivo. Efficient PanIN formation was therefore dependent on the expression of Nupr1 and RelB, with the probable involvement of IER3. Finally, a significant correlation between expression of Nupr1, RelB and IER3 and a poor prognosis of patients with PDAC was found. Altogether, our results reveal a novel stress-related pathway that requires the functional interaction of Nupr1àRelBàIER3 in KrasG12D-dependent transformation of the pancreas and expand our understanding of the molecular machinery that mediates the early steps of pancreatic carcinogenesis. Since Nupr1 belongs to the HMG family of chromatin remodelers with transcriptional co-factor activity, Nupr1 could increase cell survival in a nutrient-deprived microenvironment by activating the expression of pro-survival genes. Moreover, considering that RelB, and not RelA/p65, is essential to the Nupr1-mediated survival mechanism that takes place upon nutrient deprivation-induced stress, we made the hypothesis that the two NF-kB transcription factors should activate different sets of genes among which a pivotal pro-survival gene would be exclusively dependent on RelB. In order to test this two hypothesis, an Affymetrix microarray analysis was performed using pancreatic cancer cells transfected with siCtrl or siNupr1 and cultured for 3, 6 or 9 hrs in EBSS; or transfected with siRelB, siRelA/p65 or siCtrl and cultured for 9 hrs in EBSS or Mock.

Project description:Sorafenib, an oral multikinase inhibitor, is the only approved agent for the treatment of advanced hepatocellular carcinoma (HCC). However, its benefits is modest, also because its mechanism of action remains elusive, therefore, a better understanding of its molecular action and molecular targets are needed. On the basis of our previous studies, here, we investigated the role of the nuclear protein 1 (NUPR1) in HCC and its role in the context of sorafenib treatment. NUPR1 is a stress-inducible protein over-expressed in different malignancies, however, its role in HCC is not yet fully understood. We found that NUPR1, is over-expressed in 53% of primary human HCC samples. Knockdown of NUPR1 significantly increased cell sensitivity to sorafenib and inhibits cell growth, migration and invasion of HCC cells in vitro and tumorigenicity in vivo. Moreover, NUPR1 silencing influenced expression of target genes RelB and IER3. Unsurprisingly, RelB and IER3 knockdown also inhibited HCC cells viability, growth and migration. By gene expression profiling of HCC cells following stable NUPR1 knockdown, we found that genes functionally involved in cell death and survival, cellular response to therapies, lipid metabolism, cell growth and proliferation, molecular transport and cellular movement were mostly suppressed. Network analysis of dynamic gene expression identified NF-κB and ERK as down-regulated gene nodes, and several genes known to be involved in hepatocarcinogenesis were also suppressed. In addition, we identified Runt-related transcription factor 2 (RUNX2) gene as a NUPR1 down-regulated gene. We also demonstrated that RUNX2 gene silencing inhibited HCC cells viability, growth, migration and increased cell sensitivity to sorafenib. Conclusion: We propose that NUPR1/RELB/IER3/RUNX2 pathway play pivotal role in hepatocarcinogenesis. The identification of NUPR1/RELB/IER3/RUNX2 pathway as a potential therapeutic target may contribute to the development of new treatment strategies for HCC management.

Project description:Sorafenib, an oral multikinase inhibitor, is the only approved agent for the treatment of advanced hepatocellular carcinoma (HCC). However, its benefits is modest, also because its mechanism of action remains elusive, therefore, a better understanding of its molecular action and molecular targets are needed. On the basis of our previous studies, here, we investigated the role of the nuclear protein 1 (NUPR1) in HCC and its role in the context of sorafenib treatment. NUPR1 is a stress-inducible protein over-expressed in different malignancies, however, its role in HCC is not yet fully understood. We found that NUPR1, is over-expressed in 53% of primary human HCC samples. Knockdown of NUPR1 significantly increased cell sensitivity to sorafenib and inhibits cell growth, migration and invasion of HCC cells in vitro and tumorigenicity in vivo. Moreover, NUPR1 silencing influenced expression of target genes RelB and IER3. Unsurprisingly, RelB and IER3 knockdown also inhibited HCC cells viability, growth and migration. By gene expression profiling of HCC cells following stable NUPR1 knockdown, we found that genes functionally involved in cell death and survival, cellular response to therapies, lipid metabolism, cell growth and proliferation, molecular transport and cellular movement were mostly suppressed. Network analysis of dynamic gene expression identified NF-ÎºB and ERK as down-regulated gene nodes, and several genes known to be involved in hepatocarcinogenesis were also suppressed. In addition, we identified Runt-related transcription factor 2 (RUNX2) gene as a NUPR1 down-regulated gene. We also demonstrated that RUNX2 gene silencing inhibited HCC cells viability, growth, migration and increased cell sensitivity to sorafenib. Conclusion: We propose that NUPR1/RELB/IER3/RUNX2 pathway play pivotal role in hepatocarcinogenesis. The identification of NUPR1/RELB/IER3/RUNX2 pathway as a potential therapeutic target may contribute to the development of new treatment strategies for HCC management. To better understand the molecular mechanisms of NUPR1 gene action in ovarian HCC cells, we employed the Agilent Whole Human Genome microarrays, containing ~ 44,000 genes to identify global gene expression changes upon NUPR1 suppression in HCC cells. We compared the gene expression of the previously selected shRNA-mediated NURP1-knockdown Hep3B clone against the corresponding control (ctrl) clone. The microarray experiments were performed in duplicates, as two hybridizations were carried out for the NUPR1-suppressing cell clone against the corresponding control, using a fluorescent dye reversal (dye-swap) technique.

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The chromatin protein Nupr1 regulates RelB-dependent NF-kB events necessary for pancreatic cancer development

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