Abstract 3194: Cancer-associated fibroblast heterogeneity in neuroblastoma

Abstract

Abstract Extracellular matrix (ECM) remodeling is a critical process within the solid tumor microenvironment. Cancer associated fibroblasts (CAFs) are the primary producers of matrix proteins and remodeling enzymes that cross-link and degrade matrix proteins. CAFs are enigmatic in that they can promote or impede tumor growth, suggesting heterogeneity that is not completely understood. How CAF heterogeneity evolves over tumor progression and how this evolution impacts ECM remodeling within solid tumors remain an outstanding question across cancer models. Recent studies have focused on CAF function in models of adult cancer, but little attention has been directed toward understanding CAF heterogeneity and ECM remodeling in childhood cancers, which are etiologically different diseases. Neuroblastoma (NB) is a childhood cancer of neuroendocrine cells that accounts for 15% of pediatric cancer deaths. Like other solid tumors, the NB tumor microenvironment includes malignant cells, CAFs, and immune cells. Our laboratory studies NB using a penetrant, spontaneous model of NB (TH-MYCN, AlkF1178L/+) in immunocompetent mice, allowing in vivo investigation of the tumor immune microenvironment from tumorigenesis to progressive disease. Using this model, we previously demonstrated the pro-tumorigenic role of macrophages and CD4+ T cells by showing that their depletion significantly reduced the formation of tumors and extended survival. In this study, 10X Chromium gene expression analysis of stromal cells from nascent and mature tumors identified two distinct subsets of CAFs characterized by alpha smooth muscle actin (Acta2) and Wilms tumor 1 (Wt1) expression. Interestingly, only Wt1 CAFs expressed chemokines and cytokines involved in recruitment of myeloid and T cells. Wt1 CAFs were enriched in the early tumor microenvironment and expressed genes encoding ADAMTS enzymes involved in degradation of the proteoglycan versican. Our preliminary findings indicate that Wt1 CAFs may be a crucial early recruiter of pro-tumorigenic immune cells in our model of neuroblastoma. Citation Format: Nicolas B. Peterson, Paul G. Thomas. Cancer-associated fibroblast heterogeneity in neuroblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3194.