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Gut. 2018 Oct 12. pii: gutjnl-2017-315490. doi: 10.1136/gutjnl-2017-315490. [Epub ahead of print]

SWI/SNF component ARID1A restrains pancreatic neoplasia formation.

Author information

1
Department of Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
2
Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.
3
Department of BioInformatics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
4
Howard Hughes Medical Institute, Chevy Chase, Maryland, USA.
5
Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
6
Epizyme, Inc., Cambridge, Massachusetts, USA.
7
Department of Pathology, Stanford University, Stanford, California, USA.
#
Contributed equally

Abstract

OBJECTIVE:

ARID1A is commonly mutated in pancreatic ductal adenocarcinoma (PDAC), but the functional effects of ARID1A mutations in the pancreas are unclear. Understanding the molecular mechanisms that drive PDAC formation may lead to novel therapies.

DESIGN:

Concurrent conditional Arid1a deletion and Kras activation mutations were modelled in mice. Small-interfering RNA (siRNA) and CRISPR/Cas9 were used to abrogate ARID1A in human pancreatic ductal epithelial cells.

RESULTS:

We found that pancreas-specific Arid1a loss in mice was sufficient to induce inflammation, pancreatic intraepithelial neoplasia (PanIN) and mucinous cysts. Concurrent Kras activation accelerated the development of cysts that resembled intraductal papillary mucinous neoplasm. Lineage-specific Arid1a deletion confirmed compartment-specific tumour-suppressive effects. Duct-specific Arid1a loss promoted dilated ducts with occasional cyst and PDAC formation. Heterozygous acinar-specific Arid1a loss resulted in accelerated PanIN and PDAC formation with worse survival. RNA-seq showed that Arid1a loss induced gene networks associated with Myc activity and protein translation. ARID1A knockdown in human pancreatic ductal epithelial cells induced increased MYC expression and protein synthesis that was abrogated with MYC knockdown. ChIP-seq against H3K27ac demonstrated an increase in activated enhancers/promoters.

CONCLUSIONS:

Arid1a suppresses pancreatic neoplasia in a compartment-specific manner. In duct cells, this process appears to be associated with MYC-facilitated protein synthesis.

KEYWORDS:

cancer genetics; pancreatic cancer; pancreatic tumours

PMID:
30315093
DOI:
10.1136/gutjnl-2017-315490
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Conflict of interest statement

Competing interests: SD is an employee and stockholder of Epizyme.

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