Arid1a restrains Kras-dependent changes in acinar cell identity.

Livshits, Geulah; Alonso-Curbelo, Direna; Morris, John P; Koche, Richard; Saborowski, Michael; Wilkinson, John Erby; Lowe, Scott W · Elife · 2018

basic_science · Level V

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Abstract

Mutations in members of the SWI/SNF chromatin remodeling family are common events in cancer, but the mechanisms whereby disruption of SWI/SNF components alters tumorigenesis remain poorly understood. To model the effect of loss of function mutations in the SWI/SNF subunit Arid1a in pancreatic ductal adenocarcinoma (PDAC) initiation, we directed shRNA triggered, inducible and reversible suppression of Arid1a to the mouse pancreas in the setting of oncogenic Kras<sup>G12D</sup>. Arid1a cooperates with Kras in the adult pancreas as postnatal silencing of Arid1a following sustained Kras<sup>G12D</sup> expression induces rapid and irreversible reprogramming of acinar cells into mucinous PDAC precursor lesions. In contrast, Arid1a silencing during embryogenesis, concurrent with Kras<sup>G12D</sup> activation, leads to retention of acinar cell fate. Together, our results demonstrate Arid1a as a critical modulator of Kras-dependent changes in acinar cell identity, and underscore an unanticipated influence of timing and genetic context on the effects of SWI/SNF complex alterations in epithelial tumorigenesis.

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