Abstract B062: VCAN+ macrophages promote neuroblastoma cell growth, migration, and adrenergic to mesenchymal transition via the HB-EGF/ERBB signaling axis

Abstract Introduction: High-risk neuroblastoma (NBL) is a leading cause of pediatric cancer death and is characterized by substantial intratumoral heterogeneity leading to therapeutic resistance. Despite the significant insights from recent single-cell sequencing, the evolution of the tumor microenvironment under therapy remains obscure. We longitudinally profiled 22 high-risk NBL patients before and after induction chemotherapy through single-nucleus RNA and ATAC sequencing. We identified profound shifts in tumor and immune cell subpopulations. In particular, macrophages significantly expanded towards pro-angiogenic, immunosuppressive, and metabolic phenotypes. Through a prediction of paracrine signaling using our single-cell sequencing data, we predicted a role of the heparin-binding epidermal growth factor (HB-EGF)/Erb receptor tyrosine kinase 4 (ERBB4) signaling pathway between VCAN+ macrophages and neuroblasts. In this study, we sought to characterize the role of this signaling pathway in therapy response in high-risk neuroblastoma. Methods: We examined the interaction between malignant neuroblasts and macrophages using transwell co-culture assay. Macrophages were differentiated from the THP1 monocytes. Neuroblasts were cultured using NB1643, CHLA15, CHLA20, COG-N-297, and COG-N-590 neuroblastoma cell lines. To determine the source and activity of the HB-EGF/ERBB4/ERK signaling pathway, protein levels were determined using enzyme-linked immunosorbent assay and Western blot using co-culture supernatant and neuroblast and macrophage cell lysates. Pathway activity was modulated using CRM197 as the HB-EGF inhibitor and afatinib as the ERBB tyrosine kinase inhibitor. We examined the role of macrophage-derived HB-EGF on cell proliferation and migration by colony formation and transwell migration assays, respectively. Furthermore, we assessed the adrenergic (PHOX2B, GATA3, ALK, PHOX2A) and mesenchymal (YAP1 and PRRX1) marker expressions by real-time qPCR and Western blot. Results: We found that expression of HB-EGF in macrophages was significantly induced when co-cultured with multiple neuroblast cell lines. Binding of HB-EGF to ERBB4 in neuroblasts led to the activation of the kinase pathway and increased proliferation and migration of neuroblast cells, which can be inhibited by either HB-EGF or tyrosine kinase inhibitors. We examined adrenergic and mesenchymal marker expression in neuroblasts after prolonged co-culture with macrophages. While ALK and PHOX2B expressions were reduced, YAP1 and PRRX1 expressions increased in post-therapy CHLA20 cells but not in the paired diagnostic CHLA15 or NB1643 cells. Inhibition of the HB-EGF/ERBB pathway partially restored PHOX2B expression and reduced YAP1 and PRRX1 expression in macrophage co-cultured CHLA20 cells. Conclusion: We established the HB-EGF/ERBB4 axis between macrophage and neoplastic neuroblast, inducing ERK signaling, tumor cell proliferation, migration, and adrenergic-to-mesenchymal transition. These findings collectively reveal a novel extrinsic mechanism of therapy resistance in high-risk NBL. Citation Format: Rumeysa Biyik-Sit, Wenbao Yu, Chia-Hui Chen, Anusha Thadi, Minxing Pang, Liron D. Grossmann, Tasleema Patel, Daniel Martinez, Lea F. Surrey, Michael D. Hogarty, Kathrin Bernt, Nancy Zhang, John M. Maris, Kai Tan. VCAN+ macrophages promote neuroblastoma cell growth, migration, and adrenergic to mesenchymal transition via the HB-EGF/ERBB signaling axis [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pediatric Cancer Research; 2024 Sep 5-8; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl):Abstract nr B062.