Abstract 2895: ILRAP blockade mediates anti-fibrotic effects in pancreatic cancer-associated fibroblasts

Abstract Introduction: Pancreatic cancer (PDAC) patients have poor prognosis partly due to excessive activity of cancer-associated fibroblasts (CAFs). CAFs drive the fibrosis that causes excessive type III collagen and extracellular matrix deposition that in turn reduces drug response resulting in poor survival. In support, high levels of the type III collagen serum biomarker PRO-C3 correlates with poor survival in PDAC. TGF-β is thought to be the main driver of PRO-C3 and tumor fibrosis. Cytokines such as Interleukin 1 (IL-1) play a key role in the pancreatic tumor microenvironment and may play a role in tumor fibrosis as well. In this study, we first investigated the potential of IL-1 in activating fibroblasts to drive fibrosis and produce PRO-C3. Subsequently, we established a co-culture of pancreatic cancer cells and pancreatic CAFs to investigate the anti-fibrotic properties of nadunolimab, an antibody that blocks IL-1 signaling by targeting IL-1 Receptor Accessory Protein (IL1RAP). Nadunolimab is currently in phase I/IIa clinical development for treatment of pancreatic cancer (CANFOUR, NCT03267316). Methods: Human primary pancreatic cancer-associated fibroblasts (CAFs) were cultured in Ficoll-media (Scar-in-a-jar, SiaJ) supplemented with TGF-β, IL-1α or IL-1β. The fibrotic activity of the fibroblasts was investigated by measuring the formation of type III collagen (PRO-C3) at days 3, 6, 9 and 12. Then, pancreatic cancer cells (BxPc3) and pancreatic CAFs were cultured either alone or in a co-culture. Nadunolimab or isotype control were added at the start of these cultures and supernatants were collected after three days. The level of PRO-C3 was measured by ELISA. Results: Both IL-1α or IL-1β were equipotent to TGF-β in inducing PRO-C3 in the SiaJ monoculture, indicating that IL-1 is pro-fibrotic. In addition, when cancer cells and CAFs were co-cultured, PRO-C3 levels increased compared to single-cell cultures (1. 5-6-fold). When co-cultures were treated with nadunolimab, the induction of PRO-C3 was blocked to levels similar to monocultures, whereas the isotype control had no effect on PRO-C3 levels. Conclusion: IL-1 activated fibroblasts and induced type III collagen formation (PRO-C3), suggesting that IL-1 is a driver of tumor fibrosis. In support, pancreatic tumor cells induced collagen type III formation (PRO-C3) in pancreatic CAFs and blockade of IL1RAP with nadunolimab inhibited this collagen formation. Thus, nadunolimab may have anti-fibrotic properties and PRO-C3 could potentially be used for prognostic/predictive enrichment and as a pharmacodynamic marker in future studies evaluating anti-IL-1 modalities in PDAC. Citation Format: Neel I. Nissen, Nils Hansen, Elin Jaensson Gyllenbäck, Camilla R. Millrud, Marcus Järås, David Liberg, Morten A. Karsdal, Nicholas Willumsen. ILRAP blockade mediates anti-fibrotic effects in pancreatic cancer-associated fibroblasts 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 (6Suppl): Abstract nr 2895.