Abstract 2673: Copper chelation overcomes the immunosuppressive neuroblastoma microenvironment to potentiate anti-GD2 antibody therapy
Authors: Rouaen Jourdin R. , Salerno Antonella , Luciani Fabio , Murray Jayne , Shai-Hee Tyler , Tedla Nicodemus , Haber Michelle , Trahair Toby N. , Vittorio Orazio 
Published: March 2024

Abstract
Neuroblastoma is the most frequent extra-cranial pediatric cancer with high-risk disease possessing a dismal five-year survival rate &lt;50%. Antibody-based therapies targeting the surface disialoganglioside GD2 have shown promising anti-tumor activity in patients however efficacy is strongly hampered by immunosuppressive mechanisms present in the tumor microenvironment. Neuroblastomas typically feature low mutational burdens, limited major histocompatibility complex class I expression, increased immune checkpoint markers, sparse immune infiltration, and soluble mediators which drastically limit anti-tumor immunity. Given the emerging link between elevated copper levels and tumoral immune evasion, we explored copper chelation as a therapeutic strategy using the agents tetraethylenepentamine (TEPA) and the clinically approved analogue triethylenetetramine (TETA). Using the immunocompetent TH-MYCN model, we performed single-cell RNA sequencing supported by OPAL multiplex immunohistochemistry and cytokine profiling of resected tumors to assess cellular and molecular changes occurring after one week of TEPA treatment. Therapy was observed to successfully deplete intratumoral copper and reinvigorate anti-tumor immunity with increased infiltration and activity of pro-inflammatory immune cells, and was specifically found to induce egress and N1-polarisation of neutrophils. Further mechanistic studies in vitro revealed the sequestration of copper by neuroblastoma cells attenuated neutrophil function, which could be successfully reversed upon TEPA treatment. Findings propose a novel mechanism of immune evasion, highlighting copper chelation as a therapeutic strategy to counteract immunosuppression. Using the TH-MYCN model, TEPA was employed as a priming agent to effectively potentiate anti-GD2 antibody therapy and achieve durable tumor control. Importantly, this was associated with increased Fc-receptor-bearing natural killer and myeloid cells, which elicit tumor clearance via antibody-dependent cellular cytotoxicity. Currently indicated for the treatment of copper overload disorder Wilson’s disease, TETA was evaluated for potential repurposing as a novel immunomodulatory agent. Using the syngeneic NXS2 model, TETA exhibited an exceptional safety profile and combination therapy achieved durable tumor control with no relapses occurring after treatment cessation. This result was similarly associated with the infiltration of pro-inflammatory immune cells, including N1 neutrophils. Collectively, this study credentials copper chelation as a non-toxic strategy to disrupt the immunosuppressive tumor microenvironment and reinvigorate anti-tumour immunity. Findings provide crucial translational evidence for repurposing TETA to potentiate anti-GD2 antibody therapy and improve neuroblastoma patient responses.
Citation Format: Jourdin R. Rouaen, Antonella Salerno, Fabio Luciani, Jayne Murray, Tyler Shai-Hee, Nicodemus Tedla, Michelle Haber, Toby N. Trahair, Orazio Vittorio. Copper chelation overcomes the immunosuppressive neuroblastoma microenvironment to potentiate anti-GD2 antibody therapy [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 2673.