Title: Abstract 5294: The PanNET-related histone H3.3 chaperone Daxx regulates lineage specification and tissue homeostasis in the pancreas
Abstract: Abstract Progressive age-dependent replacement of canonical H3.1/2 with H3.3 in post-mitotic cells is a crucial mechanism for maintaining genome integrity at heterochromatic sites. The histone chaperone DAXX cooperates with the chromatin remodeller ATRX for the deposition of the non-canonical histone H3.3 at heterochromatin, while it prevents the expression of endogenous retroviral elements in another complex involving the SETDB1 methyltransferases. Loss of function mutations affecting ATRX/DAXX and MEN-1 have been recently identified as a subgroup of pancreatic neuroendocrine tumours (PanNETs) leading to poor prognosis and more aggressive phenotype compared to the ATRX/DAXX and MEN-1 wild-type counterparts. We developed a mouse model for conditional Daxx inactivation in mouse islets to understand the impact of DAXX loss on pancreas homeostasis and PanNETs development. We found that loss of Daxx in the endocrine pancreas, using the Insulin-1Cre driver, leads to aberrant glucose metabolism with the development of hyperglycemia and consequently insulin resistance in mice. We have also shown that loss of DAXX is linked to increased expression of α-cell lineage genes upon glucose stimulation of isolated islets in vitro, resembling the recently reported phenotype of PanNETs harboring ATRX/DAXX or MEN1 mutations. Nonetheless, loss of Daxx was not sufficient to lead to PanNET development. We are currently investigating the chromatin and transcriptional perturbations caused by Daxx loss and how these could be linked to the aberration of cell lineage specification and tissue dysfunction in the pancreas. More generally, this work will provide new insight into how epigenetic alterations contribute to misregulation of developmental programmes and cancer development in the pancreas. Citation Format: Teresa Sposito, Marie-Sophie Nguyen Tu, Guy A. Rutter, Marco Novelli, Chrissie Thirlwell, Paolo Salomoni. The PanNET-related histone H3.3 chaperone Daxx regulates lineage specification and tissue homeostasis in the pancreas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5294.
Publication Year: 2019
Publication Date: 2019-07-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 1
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