Abstract PR012: KRAS mutation-specific effects on the tumor immune microenvironment drive tumor progression in pancreatic cancer

Abstract

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with abysmal survival rates. The highly immunosuppressive microenvironment of PDAC poses a major barrier to effective therapy. KRAS mutations are near-ubiquitous in PDAC, and studies indicate clinical outcomes vary depending on the specific KRAS genotype. Given that tumor genotype can shape the immune cell composition of tumors, we examined the immune cell composition of pancreatic tumors with specific KRAS mutations, focusing on KRASG12D mutations (representing 40% of PDAC cases which have the worst prognosis) and KRASG12R mutations (which make up 20% of PDAC cases and have a better prognosis). Orthotopically implanted Kras G12R/+ ;Trp53 KO mouse pancreatic tumors have a distinct immune profile in comparison to Kras G12D/+ ;Trp53 KO tumors, characterized by an influx of intratumoral CD3+ T cells and mature dendritic cells. Selective depletion of CD4+ T cells induces a rapid progression in KRASG12R, but not KRASG12D mouse tumors. RNA sequencing of KRASG12R tumor cells revealed enrichment of Type I interferon (IFN) pathways accompanied by related chemokines, CXCL9 and CXCL10 in comparison to KRASG12D tumors. Analysis of publicly available and real-world human PDAC datasets and enrichment of dendritic cells and other immune related cell types in KRASG12R tumors. Collectively, these data link the KRASG12R mutation to a unique immunogenic role. Citation Format: Andrew Wenger, Tal Baron, Erika Hissong, Rohit Chandiwani, Lukas Dow, Despina Siolas, Katherine Bacchi, Huanhuan Sun, Erika Hissong, Adrian Vega, Whitney Sisso, and Kawther Abdilleh. KRAS mutation-specific effects on the tumor immune microenvironment drive tumor progression in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr PR012.