Abstract 6816: Prevention of cancer cachexia by inhibition of soluble epoxide hydrolase

Abstract Background: Cancer cachexia is a devastating syndrome characterized by progressive muscle wasting and hyperinflammation. The underlying mechanisms remain poorly understood with no treatment options available. Cachexia is driven by systemic inflammation, pro-inflammatory cytokines, and apoptotic cell death (debris). The resolution of inflammation as an active biochemical process is regulated by novel pro-resolving lipid mediators. Arachidonic acid-derived epoxyeicosatrienoic acids (EETs) are lipid mediators stimulating inflammation resolution. EETs are rapidly metabolized by the enzyme soluble epoxide hydrolase (sEH). sEH is a critical cause of inflammation and a biomarker in several chronic inflammatory diseases. sEH inhibitors promote tissue regeneration and counter-regulate pro-inflammatory cytokines. We hypothesized that pharmacological inhibition of the sEH may prevent cachexia. Methods: We investigated murine cancer cachexia models using genetically engineered pancreatic (KPC) and prostate (TRAMP C1) tumor cell lines, and “TRAMP” mice (transgenic adenocarcinoma of the mouse prostate). We performed LC-MS/MS-based profiling of bioactive lipids in plasma from KPC and colon cancer (CT26)-induced cachectic mice. Results: KPC cells injected intraperitoneally induced 19.7% and 54.1% reduction in muscle weight in the tibialis anterior and soleus, respectively, in immunocompetent C57BL/6 mice compared to non-tumor bearing (NTB) mice. LC-MS/MS revealed KPC and CT26 cachexia induced a pro-inflammatory eicosanoid-driven cytokine storm. The human sEH inhibitor EC5026 delayed the onset of cachexia, leading to sustained survival over 250 days post-injection in the KPC model (n=15 mice/group). sEH expression was increased in the gastrocnemius of KPC mice by day 22 post-tumor cell injection vs. NTB. EC5026 counter-regulated sEH expression compared to vehicle-treated. In the TRAMP model, 5/5 of mice treated with EC5026 survived 230 days post-treatment compared to no survival of vehicle-treated mice (n=5). The transplanted KPC and TRAMP showed reduced CD4+ and CD8+ T lymphocytes and B lymphocytes in the tibialis anterior and gastrocnemius vs. NTB after flow cytometry analysis. EC5026 stimulated a general increase in CD3+ T lymphocytes and counter-regulated an eicosanoid-driven cytokine storm as shown by cytokine assays. EC5026 treatment increased tibialis anterior and gastrocnemius muscle weights and body weights compared to vehicle-treated KPC and TRAMP mice. Conclusions: sEH inhibition may be a novel therapeutic approach to cachexia by targeting the immune response via stimulation of resolution of inflammation without toxicity or immunosuppression. Since sEH inhibitors have proven safe and effective in clinical trials for controlling multiple inflammatory diseases, this study provides a basis for the rapid clinical translation of sEH inhibitors to prevent/reverse cachexia in cancer patients. Citation Format: Rachel L. Bayer, Sarina Virani, Michael Gillespie, Jacqueline Capuano, Keira Smith, Katherine Quinlivan, Kimberly Vasquez, Jun Yang, Haixia Yang, Nicholas Mitsiades, Bruce D. Hammock, Dipak Panigrahy. Prevention of cancer cachexia by inhibition of soluble epoxide hydrolase [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6816.