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Gastroenterology. 2016 Sep;151(3):526-39. doi: 10.1053/j.gastro.2016.05.006. Epub 2016 May 20.

YAP1 and TAZ Control Pancreatic Cancer Initiation in Mice by Direct Up-regulation of JAK-STAT3 Signaling.

Author information

1
Mammalian Genetics Laboratory, The Francis Crick Institute, Lincoln's Inn Fields Laboratory, London, UK.
2
Transcription Laboratory, The Francis Crick Institute, Lincoln's Inn Fields Laboratory, London, UK.
3
Experimental Histopathology, The Francis Crick Institute, Lincoln's Inn Fields Laboratory, London, UK.
4
Mammalian Genetics Laboratory, The Francis Crick Institute, Lincoln's Inn Fields Laboratory, London, UK; School of Medicine, King's College London, London, UK. Electronic address: Axel.Behrens@crick.ac.uk.

Abstract

BACKGROUND & AIMS:

Pancreatitis is the most important risk factor for pancreatic ductal adenocarcinoma (PDAC). Pancreatitis predisposes to PDAC because it induces a process of acinar cell reprogramming known as acinar-to-ductal metaplasia (ADM)-a precursor of pancreatic intraepithelial neoplasia lesions that can progress to PDAC. Mutations in KRAS are found at the earliest stages of pancreatic tumorigenesis, and it appears to be a gatekeeper to cancer progression. We investigated how mutations in KRAS cooperate with pancreatitis to promote pancreatic cancer progression in mice.

METHODS:

We generated mice carrying conditional alleles of Yap1 and Taz and disrupted Yap1 and Taz using a Cre-lox recombination strategy in adult mouse pancreatic acinar cells (Yap1fl/fl;Tazfl/fl;Ela1-CreERT2). We crossed these mice with LSL-KrasG12D mice, which express a constitutively active form of KRAS after Cre recombination. Pancreatic tumor initiation and progression were analyzed after chemically induced pancreatitis. We analyzed pancreatic tissues from patients with pancreatitis or PDAC by immunohistochemistry.

RESULTS:

Oncogenic activation of KRAS in normal, untransformed acinar cells in the pancreatic tissues of mice resulted in increased levels of pancreatitis-induced ADM. Expression of the constitutive active form of KRAS in this system led to activation of the transcriptional regulators YAP1 and TAZ; their function was required for pancreatitis-induced ADM in mice. The JAK-STAT3 pathway was a downstream effector of KRAS signaling via YAP1 and TAZ. YAP1 and TAZ directly mediated transcriptional activation of several genes in the JAK-STAT3 signaling pathway; this could be a mechanism by which acinar cells that express activated KRAS become susceptible to inflammation.

CONCLUSIONS:

We identified a mechanism by which oncogenic KRAS facilitates ADM and thereby generates the cells that initiate neoplastic progression. This process involves activation of YAP1 and TAZ in acinar cells, which up-regulate JAK-STAT3 signaling to promote development of PDAC in mice.

KEYWORDS:

Inflammation; Mouse Model; PanINs; Pancreatic Cancer Progression

Comment in

PMID:
27215660
PMCID:
PMC5007286
DOI:
10.1053/j.gastro.2016.05.006
[Indexed for MEDLINE]
Free PMC Article

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