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Prevention and Reversion of Pancreatic Tumorigenesis through a Differentiation-Based Mechanism.
Krah NM, Narayanan SM, Yugawa DE, Straley JA, Wright CVE, MacDonald RJ, Murtaugh LC
(2019) Dev Cell 50: 744-754.e4
MeSH Terms: Acinar Cells, Animals, Carcinogenesis, Cell Differentiation, Cell Line, Tumor, Cell Proliferation, Clone Cells, Disease Models, Animal, Gene Expression Regulation, Neoplastic, Humans, Inflammation, Mice, Pancreatic Neoplasms, Pancreatitis, Phenotype, Proto-Oncogene Proteins p21(ras), Signal Transduction, Transcription Factors
Show Abstract · Added September 3, 2019
Activating mutations in Kras are nearly ubiquitous in human pancreatic cancer and initiate precancerous pancreatic intraepithelial neoplasia (PanINs) when induced in mouse acinar cells. PanINs normally take months to form but are accelerated by deletion of acinar cell differentiation factors such as Ptf1a, suggesting that loss of cell identity is rate limiting for pancreatic tumor initiation. Using a genetic mouse model that allows for independent control of oncogenic Kras and Ptf1a expression, we demonstrate that sustained Ptf1a is sufficient to prevent Kras-driven tumorigenesis, even in the presence of tumor-promoting inflammation. Furthermore, reintroducing Ptf1a into established PanINs reverts them to quiescent acinar cells in vivo. Similarly, Ptf1a re-expression in human pancreatic cancer cells inhibits their growth and colony-forming ability. Our results suggest that reactivation of an endogenous differentiation program can prevent and reverse oncogene-driven transformation in cells harboring tumor-driving mutations, introducing a potential paradigm for solid tumor prevention and treatment.
Copyright © 2019 Elsevier Inc. All rights reserved.
1 Communities
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18 MeSH Terms
Differential Cell Susceptibilities to Kras in the Setting of Obstructive Chronic Pancreatitis.
Shi C, Pan FC, Kim JN, Washington MK, Padmanabhan C, Meyer CT, Kopp JL, Sander M, Gannon M, Beauchamp RD, Wright CV, Means AL
(2019) Cell Mol Gastroenterol Hepatol 8: 579-594
MeSH Terms: Acinar Cells, Animals, Carcinogenesis, Carcinoma, Pancreatic Ductal, Cell Transformation, Neoplastic, Disease Models, Animal, Genes, ras, Metaplasia, Mice, Mutation, Pancreatic Neoplasms, Pancreatitis, Chronic, Precancerous Conditions, Proto-Oncogene Proteins p21(ras), Signal Transduction
Show Abstract · Added August 6, 2019
BACKGROUND & AIMS - Activating mutation of the KRAS gene is common in some cancers, such as pancreatic cancer, but rare in other cancers. Chronic pancreatitis is a predisposing condition for pancreatic ductal adenocarcinoma (PDAC), but how it synergizes with KRAS mutation is not known.
METHODS - We used a mouse model to express an activating mutation of Kras in conjunction with obstruction of the main pancreatic duct to recapitulate a common etiology of human chronic pancreatitis. Because the cell of origin of PDAC is not clear, Kras mutation was introduced into either duct cells or acinar cells.
RESULTS - Although Kras expression in both cell types was protective against damage-associated cell death, chronic pancreatitis induced p53, p21, and growth arrest only in acinar-derived cells. Mutant duct cells did not elevate p53 or p21 expression and exhibited increased proliferation driving the appearance of PDAC over time.
CONCLUSIONS - One mechanism by which tissues may be susceptible or resistant to KRAS-initiated tumorigenesis is whether they undergo a p53-mediated damage response. In summary, we have uncovered a mechanism by which inflammation and intrinsic cellular programming synergize for the development of PDAC.
Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.
2 Communities
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15 MeSH Terms
Regulation of the Pancreatic Exocrine Differentiation Program and Morphogenesis by Onecut 1/Hnf6.
Kropp PA, Zhu X, Gannon M
(2019) Cell Mol Gastroenterol Hepatol 7: 841-856
MeSH Terms: Acinar Cells, Animals, Animals, Newborn, Base Sequence, Cell Differentiation, Cell Proliferation, Embryo, Mammalian, Epithelium, Gene Expression Regulation, Developmental, Hepatocyte Nuclear Factor 6, Mice, Morphogenesis, Pancreas, Exocrine
Show Abstract · Added March 29, 2019
BACKGROUND & AIMS - The Onecut 1 transcription factor (Oc1, a.k.a. HNF6) promotes differentiation of endocrine and duct cells of the pancreas; however, it has no known role in acinar cell differentiation. We sought to better understand the role of Oc1 in exocrine pancreas development and to identify its direct transcriptional targets.
METHODS - Pancreata from Oc1 (Oc1;Pdx1-Cre) mouse embryos and neonates were analyzed morphologically. High-throughput RNA-sequencing was performed on control and Oc1-deficient pancreas; chromatin immunoprecipitation sequencing was performed on wild-type embryonic mouse pancreata to identify direct Oc1 transcriptional targets. Immunofluorescence labeling was used to confirm the RNA-sequencing /chromatin immunoprecipitation sequencing results and to further investigate the effects of Oc1 loss on acinar cells.
RESULTS - Loss of Oc1 from the developing pancreatic epithelium resulted in disrupted duct and acinar cell development. RNA-sequencing revealed decreased expression of acinar cell regulatory factors (Nr5a2, Ptf1a, Gata4, Mist1) and functional genes (Amylase, Cpa1, Prss1, Spink1) at embryonic day (e) 18.5 in Oc1 samples. Approximately 1000 of the altered genes were also identified as direct Oc1 targets by chromatin immunoprecipitation sequencing, including most of the previously noted genes. By immunolabeling, we confirmed that Amylase, Mist1, and GATA4 protein levels are significantly decreased by P2, and Spink1 protein levels were significantly reduced and mislocalized. The pancreatic duct regulatory factors Hnf1β and FoxA2 were also identified as direct Oc1 targets.
CONCLUSIONS - These findings confirm that Oc1 is an important regulator of both duct and acinar cell development in the embryonic pancreas. Novel transcriptional targets of Oc1 have now been identified and provide clarity into the mechanisms of Oc1 transcriptional regulation in the developing exocrine pancreas. Oc1 can now be included in the gene-regulatory network of acinar cell regulatory genes. Oc1 regulates other acinar cell regulatory factors and acinar cell functional genes directly, and it can also regulate some acinar cell regulatory factors (eg, Mist1) indirectly. Oc1 therefore plays an important role in acinar cell development.
Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.
1 Communities
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13 MeSH Terms
Stochastic priming and spatial cues orchestrate heterogeneous clonal contribution to mouse pancreas organogenesis.
Larsen HL, Martín-Coll L, Nielsen AV, Wright CVE, Trusina A, Kim YH, Grapin-Botton A
(2017) Nat Commun 8: 605
MeSH Terms: Acinar Cells, Animals, Cell Differentiation, Cell Lineage, Cell Proliferation, Computer Simulation, Gene Expression Profiling, Mice, Organogenesis, Pancreas, Single-Cell Analysis
Show Abstract · Added October 3, 2017
Spatiotemporal balancing of cellular proliferation and differentiation is crucial for postnatal tissue homoeostasis and organogenesis. During embryonic development, pancreatic progenitors simultaneously proliferate and differentiate into the endocrine, ductal and acinar lineages. Using in vivo clonal analysis in the founder population of the pancreas here we reveal highly heterogeneous contribution of single progenitors to organ formation. While some progenitors are bona fide multipotent and contribute progeny to all major pancreatic cell lineages, we also identify numerous unipotent endocrine and ducto-endocrine bipotent clones. Single-cell transcriptional profiling at E9.5 reveals that endocrine-committed cells are molecularly distinct, whereas multipotent and bipotent progenitors do not exhibit different expression profiles. Clone size and composition support a probabilistic model of cell fate allocation and in silico simulations predict a transient wave of acinar differentiation around E11.5, while endocrine differentiation is proportionally decreased. Increased proliferative capacity of outer progenitors is further proposed to impact clonal expansion.
1 Communities
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11 MeSH Terms
c-Myc downregulation is required for preacinar to acinar maturation and pancreatic homeostasis.
Sánchez-Arévalo Lobo VJ, Fernández LC, Carrillo-de-Santa-Pau E, Richart L, Cobo I, Cendrowski J, Moreno U, Del Pozo N, Megías D, Bréant B, Wright CV, Magnuson M, Real FX
(2018) Gut 67: 707-718
MeSH Terms: Acinar Cells, Animals, Cell Differentiation, Disease Models, Animal, Down-Regulation, Homeostasis, Mice, Pancreas, Pancreatic Neoplasms, Proto-Oncogene Proteins c-myc, Transcription Factors
Show Abstract · Added February 7, 2017
BACKGROUND AND AIMS - c-Myc is highly expressed in pancreatic multipotent progenitor cells (MPC) and in pancreatic cancer. The transition from MPC to unipotent acinar progenitors is associated with c-Myc downregulation; a role for c-Myc in this process, and its possible relationship to a role in cancer, has not been established.
DESIGN - Using coimmunoprecipitation assays, we demonstrate that c-Myc and Ptf1a interact. Using reverse transcriptase qPCR, western blot and immunofluorescence, we show the erosion of the acinar programme. To analyse the genomic distribution of c-Myc and Ptf1a and the global transcriptomic profile, we used ChIP-seq and RNA-seq, respectively; validation was performed with ChIP-qPCR and RT-qPCR. Lineage-tracing experiments were used to follow the effect of c-Myc overexpression in preacinar cells on acinar differentiation.
RESULTS - c-Myc binds and represses the transcriptional activity of Ptf1a c-Myc overexpression in preacinar cells leads to a massive erosion of differentiation. In adult mice: (1) c-Myc binds to Ptf1a, and Tcf3 is downregulated; (2) Ptf1a and c-Myc display partially overlapping chromatin occupancy but do not bind the same E-boxes; (3) at the proximal promoter of genes coding for digestive enzymes, we find reduced PTF1 binding and increased levels of repressive chromatin marks and PRC2 complex components. Lineage tracing of committed acinar precursors reveals that c-Myc overexpression does not restore multipotency but allows the persistence of a preacinar-like cell population. In addition, mutant KRas can lead to c-Myc overexpression and acinar dysregulation.
CONCLUSIONS - c-Myc repression during development is crucial for the maturation of preacinar cells, and c-Myc overexpression can contribute to pancreatic carcinogenesis through the induction of a dedifferentiated state.
Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.
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11 MeSH Terms
PDX1 dynamically regulates pancreatic ductal adenocarcinoma initiation and maintenance.
Roy N, Takeuchi KK, Ruggeri JM, Bailey P, Chang D, Li J, Leonhardt L, Puri S, Hoffman MT, Gao S, Halbrook CJ, Song Y, Ljungman M, Malik S, Wright CV, Dawson DW, Biankin AV, Hebrok M, Crawford HC
(2016) Genes Dev 30: 2669-2683
MeSH Terms: Acinar Cells, Animals, Carcinoma, Pancreatic Ductal, Cell Transformation, Neoplastic, Gene Deletion, Gene Expression Regulation, Neoplastic, Homeodomain Proteins, Humans, Mice, Pancreatic Neoplasms, Tissue Array Analysis, Trans-Activators, Tumor Cells, Cultured
Show Abstract · Added February 7, 2017
Aberrant activation of embryonic signaling pathways is frequent in pancreatic ductal adenocarcinoma (PDA), making developmental regulators therapeutically attractive. Here we demonstrate diverse functions for pancreatic and duodenal homeobox 1 (PDX1), a transcription factor indispensable for pancreas development, in the progression from normal exocrine cells to metastatic PDA. We identify a critical role for PDX1 in maintaining acinar cell identity, thus resisting the formation of pancreatic intraepithelial neoplasia (PanIN)-derived PDA. Upon neoplastic transformation, the role of PDX1 changes from tumor-suppressive to oncogenic. Interestingly, subsets of malignant cells lose PDX1 expression while undergoing epithelial-to-mesenchymal transition (EMT), and PDX1 loss is associated with poor outcome. This stage-specific functionality arises from profound shifts in PDX1 chromatin occupancy from acinar cells to PDA. In summary, we report distinct roles of PDX1 at different stages of PDA, suggesting that therapeutic approaches against this potential target need to account for its changing functions at different stages of carcinogenesis. These findings provide insight into the complexity of PDA pathogenesis and advocate a rigorous investigation of therapeutically tractable targets at distinct phases of PDA development and progression.
© 2016 Roy et al.; Published by Cold Spring Harbor Laboratory Press.
1 Communities
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13 MeSH Terms
Pancreatic Inflammation Redirects Acinar to β Cell Reprogramming.
Clayton HW, Osipovich AB, Stancill JS, Schneider JD, Vianna PG, Shanks CM, Yuan W, Gu G, Manduchi E, Stoeckert CJ, Magnuson MA
(2016) Cell Rep 17: 2028-2041
MeSH Terms: Acinar Cells, Adenoviridae, Alleles, Animals, Cellular Reprogramming, Diabetes Mellitus, Experimental, Doxycycline, Gene Expression Profiling, Homeodomain Proteins, Immunity, Inflammation, Insulin-Secreting Cells, Macrophages, Metaplasia, Mice, Transgenic, Organ Size, Pancreas, Pancreatic Ducts, Reproducibility of Results, Transcription Factors, Transgenes
Show Abstract · Added November 18, 2016
Using a transgenic mouse model to express MafA, Pdx1, and Neurog3 (3TF) in a pancreatic acinar cell- and doxycycline-dependent manner, we discovered that the outcome of transcription factor-mediated acinar to β-like cellular reprogramming is dependent on both the magnitude of 3TF expression and on reprogramming-induced inflammation. Overly robust 3TF expression causes acinar cell necrosis, resulting in marked inflammation and acinar-to-ductal metaplasia. Generation of new β-like cells requires limiting reprogramming-induced inflammation, either by reducing 3TF expression or by eliminating macrophages. The new β-like cells were able to reverse streptozotocin-induced diabetes 6 days after inducing 3TF expression but failed to sustain their function after removal of the reprogramming factors.
Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.
2 Communities
2 Members
2 Resources
21 MeSH Terms
Transcriptional Maintenance of Pancreatic Acinar Identity, Differentiation, and Homeostasis by PTF1A.
Hoang CQ, Hale MA, Azevedo-Pouly AC, Elsässer HP, Deering TG, Willet SG, Pan FC, Magnuson MA, Wright CV, Swift GH, MacDonald RJ
(2016) Mol Cell Biol 36: 3033-3047
MeSH Terms: Acinar Cells, Animals, Cell Differentiation, Gene Expression Profiling, Gene Expression Regulation, Gene Knockout Techniques, Homeostasis, Mice, Pancreas, Exocrine, Protein Unfolding, Sequence Analysis, RNA, Transcription Factors, Transcription, Genetic, Unfolded Protein Response
Show Abstract · Added November 1, 2016
Maintenance of cell type identity is crucial for health, yet little is known of the regulation that sustains the long-term stability of differentiated phenotypes. To investigate the roles that key transcriptional regulators play in adult differentiated cells, we examined the effects of depletion of the developmental master regulator PTF1A on the specialized phenotype of the adult pancreatic acinar cell in vivo Transcriptome sequencing and chromatin immunoprecipitation sequencing results showed that PTF1A maintains the expression of genes for all cellular processes dedicated to the production of the secretory digestive enzymes, a highly attuned surveillance of unfolded proteins, and a heightened unfolded protein response (UPR). Control by PTF1A is direct on target genes and indirect through a ten-member transcription factor network. Depletion of PTF1A causes an imbalance that overwhelms the UPR, induces cellular injury, and provokes acinar metaplasia. Compromised cellular identity occurs by derepression of characteristic stomach genes, some of which are also associated with pancreatic ductal cells. The loss of acinar cell homeostasis, differentiation, and identity is directly relevant to the pathologies of pancreatitis and pancreatic adenocarcinoma.
Copyright © 2016, American Society for Microbiology. All Rights Reserved.
2 Communities
2 Members
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14 MeSH Terms
Prox1-Heterozygosis Sensitizes the Pancreas to Oncogenic Kras-Induced Neoplastic Transformation.
Drosos Y, Neale G, Ye J, Paul L, Kuliyev E, Maitra A, Means AL, Washington MK, Rehg J, Finkelstein DB, Sosa-Pineda B
(2016) Neoplasia 18: 172-84
MeSH Terms: Acinar Cells, Animals, Cell Transformation, Neoplastic, Ceruletide, Heterozygote, Homeodomain Proteins, Humans, Inflammation, Metaplasia, Mice, Pancreas, Pancreatic Neoplasms, Proto-Oncogene Proteins p21(ras), Tumor Suppressor Proteins
Show Abstract · Added April 11, 2016
The current paradigm of pancreatic neoplastic transformation proposes an initial step whereby acinar cells convert into acinar-to-ductal metaplasias, followed by progression of these lesions into neoplasias under sustained oncogenic activity and inflammation. Understanding the molecular mechanisms driving these processes is crucial to the early diagnostic and prevention of pancreatic cancer. Emerging evidence indicates that transcription factors that control exocrine pancreatic development could have either, protective or facilitating roles in the formation of preneoplasias and neoplasias in the pancreas. We previously identified that the homeodomain transcription factor Prox1 is a novel regulator of mouse exocrine pancreas development. Here we investigated whether Prox1 function participates in early neoplastic transformation using in vivo, in vitro and in silico approaches. We found that Prox1 expression is transiently re-activated in acinar cells undergoing dedifferentiation and acinar-to-ductal metaplastic conversion. In contrast, Prox1 expression is largely absent in neoplasias and tumors in the pancreas of mice and humans. We also uncovered that Prox1-heterozygosis markedly increases the formation of acinar-to-ductal-metaplasias and early neoplasias, and enhances features associated with inflammation, in mouse pancreatic tissues expressing oncogenic Kras. Furthermore, we discovered that Prox1-heterozygosis increases tissue damage and delays recovery from inflammation in pancreata of mice injected with caerulein. These results are the first demonstration that Prox1 activity protects pancreatic cells from acute tissue damage and early neoplastic transformation. Additional data in our study indicate that this novel role of Prox1 involves suppression of pathways associated with inflammatory responses and cell invasiveness.
Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.
0 Communities
2 Members
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14 MeSH Terms
The acinar differentiation determinant PTF1A inhibits initiation of pancreatic ductal adenocarcinoma.
Krah NM, De La O JP, Swift GH, Hoang CQ, Willet SG, Chen Pan F, Cash GM, Bronner MP, Wright CV, MacDonald RJ, Murtaugh LC
(2015) Elife 4:
MeSH Terms: Acinar Cells, Adenocarcinoma, Animals, Carcinoma in Situ, Carcinoma, Pancreatic Ductal, Cell Transdifferentiation, Disease Models, Animal, Gene Expression Profiling, Humans, Mice, Transcription Factors
Show Abstract · Added August 4, 2015
Understanding the initiation and progression of pancreatic ductal adenocarcinoma (PDAC) may provide therapeutic strategies for this deadly disease. Recently, we and others made the surprising finding that PDAC and its preinvasive precursors, pancreatic intraepithelial neoplasia (PanIN), arise via reprogramming of mature acinar cells. We therefore hypothesized that the master regulator of acinar differentiation, PTF1A, could play a central role in suppressing PDAC initiation. In this study, we demonstrate that PTF1A expression is lost in both mouse and human PanINs, and that this downregulation is functionally imperative in mice for acinar reprogramming by oncogenic KRAS. Loss of Ptf1a alone is sufficient to induce acinar-to-ductal metaplasia, potentiate inflammation, and induce a KRAS-permissive, PDAC-like gene expression profile. As a result, Ptf1a-deficient acinar cells are dramatically sensitized to KRAS transformation, and reduced Ptf1a greatly accelerates development of invasive PDAC. Together, these data indicate that cell differentiation regulators constitute a new tumor suppressive mechanism in the pancreas.
1 Communities
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11 MeSH Terms