PbSMARCD3 is a key epigenetic dependency for pancreatic adenocarcinoma

ABSTRACT: Pancreatic ductal adenocarcinoma (PDAC) is a disease characterized by extensive resistance to conventional therapies, making clinical management a significant challenge. As cancer progresses, developmental signals are often aberrantly re-activated, driving the self-renewal of cancer cells and fueling therapy resistance. To understand the epigenetic regulators that may be required to sustain these aggressive cells, we carried out a focused screen and identified SMARCD3 as a new functional dependency in pancreatic cancer. SMARCD3, a subunit of the SWI/SNF nucleosome remodeling complex, was uniquely up-regulated in PDAC stem cells and amplified in human cancer. Using a dual-recombinase model of pancreatic cancer, we showed that stage-specific conditional genetic deletion of Smarcd3 preferentially impaired growth of established tumors, improving survival and synergizing with chemotherapy. Consistent with this, SMARCD3 was required for the in vivo propagation of patient-derived xenografts. Mechanistically, we found that SMARCD3 is incorporated in the BAF complex variant of SWI/SNF. Using comprehensive ChIP-seq analysis to map the SMARCD3-dependent epigenome we showed that Smarcd3 inhibition drives global losses in histone acetylation and BAF binding at active enhancers co-bound by FOXA1. Integrating this with RNA-seq analysis, we found that SMARCD3-BAF regulated a network of genes implicated in diverse programs converging on lipid homeostasis. Specifically, Smarcd3 deletion in vivo inhibited fatty acid metabolism, which is known to be enriched within therapy-resistant cancer cells. These data collectively identify SMARCD3 as a critical dependency in PDAC and link SWI/SNF with the epigenetic control of cell state and metabolism in PDAC.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Mus Musculus (ncbitaxon:10090)

SUBMITTER: Diana Hargreaves  

PROVIDER: MSV000090744 | MassIVE | Fri Nov 18 16:59:00 GMT 2022

SECONDARY ACCESSION(S): PXD038216

REPOSITORIES: MassIVE