Abstract C098: Targeting high-expression LGR5 by an R-spondin-based peptibody-drug conjugate is efficacious against neuroblastoma

Abstract

Abstract Neuroblastoma (NB) is a pediatric tumor that predominantly affects infants and young children, with high-risk (HR) disease being diagnosed in approximately 50% of patients at 18 months or older. LGR4-6 are membrane receptors that bind RSPO ligands, activating Wnt signaling. LGR5, specifically expressed in adult stem cells, is highly upregulated in gastrointestinal (GI) cancers. In NB, high LGR5 expression is associated with aggressive disease and poor outcomes. Knockdown of LGR5 reduces cell growth in LGR5-high NB cell lines. The R-spondin-LGR5 axis has emerged as a potential therapeutic target due to its involvement in stem cell proliferation and self-renewal, as well as its overexpression in certain cancers, including neuroblastoma. RSPO-based peptibody drug conjugate (PDC) is a promising approach to target LGR4/5 for HR-NB therapy. PDCs are designed to selectively deliver the potent Pyrrolobenzodiazepine (PBD) dimer SG3199 to LGR5 high-expressing neuroblastoma cells using a peptibody that mimics the R-spondin binding activity of LGR5 ligands. Our preclinical study showed the efficacy of DAR2 R-spondin-based PDCs, generated through microbial transglutaminase-mediated site-specific conjugation, inducing cell death both in vitro and in vivo. Furthermore, these PDCs demonstrate reduced tumor growth and improved survival in xenograft animal models of neuroblastoma derived from the SK-N-AS cell lines. Our findings suggest that targeting LGR5 with RSPO2-based PDCs may offer a promising potential for treating neuroblastoma. Citation Format: Yukimatsu Toh. Targeting high-expression LGR5 by an R-spondin-based peptibody-drug conjugate is efficacious against neuroblastoma [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C098.