Abstract PO-036: Defining the role of chromatin remodelers in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a disease characterized by aggressive metastasis and resistance to therapy, making clinical management a significant challenge. We have focused on understanding how pancreatic cancer may be influenced by developmental and stem cell signals as they are often aberrantly re-activated during cancer progression. Given the central role for epigenetic regulation in development, we hypothesized that epigenetic factors may be required to sustain the self-renewal and aggressive nature of pancreatic cancer cells. To this end, we carried out a functional screen and identified Smarcd3, a component of the SWI/SNF (Baf) nucleosome remodeling complex, as a novel functional dependency in PDAC. SWI/SNF coordinates context-specific gene regulation in development and is frequently dysregulated in cancer. However, Smarcd3 has not been linked to functions in PDAC and represents a new epigenetic mediator of tumorigenesis. We found that Smarcd3 was uniquely up-regulated in PDAC stem cells and was required for the in vivo propagation of mouse and patient-derived tumors. Further using integrated RNA-seq, ChIP-seq, and network analysis we found that Smarcd3 regulates global SWI/SNF binding and histone acetylation, driving the epigenetic regulation of core cell fate and metabolic programs. Specifically, we found that Smarcd3 regulated genes converging on the mevalonate pathway and ultimately cholesterol biosynthesis, which has been directly implicated in stem signaling in PDAC. Collectively, these data identify Smarcd3 as a critical novel dependency and epigenetic regulator of pancreatic cancer metabolism. Citation Format: Lesley Paige Ferguson, Jovylyn Gatchalian, Nikki Lytle, Nirakar Rajbhandari, Matthew McDermott, Kendall Chambers, Sara Brin Rosenthal, Christian Schuerch, Inti Zlobec, Marten Wartenberg, Eva Diamantis, Jose A. Galvan, Sonia Albini, Lorenzo Puri, Benoit Bruneau, Andrew M. Lowy, Diana Hargreaves, Tannishtha Reya. Defining the role of chromatin remodelers in pancreatic cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2020 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2020;80(22 Suppl):Abstract nr PO-036.