Abstract A018: Exercise stimulates anti-tumoral immunity in metastatic PDAC

Abstract

Abstract The majority of pancreatic ductal adenocarcinoma (PDAC) patients are metastatic at presentation with limited treatment options and a poor overall 5-year survival of 3%. The liver is the predominant site of distant metastasis in PDAC. Our group has previously shown that aerobic exercise can inhibit tumorigenesis in a primary PDAC mouse model by promoting anti-tumor immunity, however, the effects of exercise in the metastatic setting have not been explored. As such, we developed a model of PDAC liver metastasis by isolating primary pancreatic and liver metastatic cell lines from 18–20-week-old LSL-KRasG12D/+; LSL-Trp53R172H/+; p48Cre; Rosa26LSL-tdTomato/+ (KPCTpancreas or KPCTliver, respectively) mice. KPCTpancreas cells were surgically implanted into the pancreata of syngeneic wild-type mice. One week after pancreatic implantation, KPCTliver cells were implanted into the liver either by direct injection into the parenchyma or via the portal vein. The portal vein method enables us to account for the extravasation step of the metastatic cascade, while the direct parenchymal injection offers a less invasive surgery. Both models preserve the spleen, which is the largest secondary lymphoid organ and essential to the immune response. Treadmill running was initiated in the aerobic exercise cohort 5 days per week for 2 weeks or mice were allowed to rest. Endpoint analysis revealed that aerobic exercise treatment decreased tumor burden in both primary tumors and liver metastasis as measured by tumor weights and tdTomato fluorescence imaging when compared to the rested controls. Immune profiling of the liver metastases revealed elevated IL-15Rɑ+ CD8+ T cells as well as CD19+ B cells in the exercise cohort. While identification of IL-15Rɑ+ CD8+ T cells is consistent with the immune changes we have previously reported in the primary pancreatic tumor of exercised mice, the latter changes reveal organ specific immune cell recruitment not observed in the primary pancreatic tumor of exercised mice. The combined immune profiling and phenotypic changes suggest that aerobic exercise reduces PDAC metastatic growth by modulating systemic and intra-tumoral immunity. The induction of an anti-tumorigenic immune response by aerobic exercise could open avenues for potential pharmacological intervention in downstream pathways to aid in the treatment of metastatic PDAC. Citation Format: Mansour E. Riachi, Carolina G. Alcantara Hirsch, Erica Ma, Beny Shapiro, Ammar Javed, Christopher L. Wolfgang, Dafna Bar-Sagi. Exercise stimulates anti-tumoral immunity in metastatic PDAC [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A018.