Abstract 698: Novel reporter tool for visualization of neuroblastoma cell state.

Abstract Over fifty percent of patients diagnosed with neuroblastoma (NBL) will relapse with therapy resistant tumors. The 5-year survival rate of NBL relapse is less than 10%, leaving a desperate need to understand how these tumors recur. NBL tumors are heterogeneous and made up of two major cell populations derived from proliferating sympathoblasts: mesenchymal (MES) and adrenergic (ADRN). The central hypothesis is that the MES cell population evades standard of care treatments and re-establishes tumor recurrence in NBL. To better understand the dynamic of ADRN and MES cell states in tumor recurrence, a reporter was designed to visualize cell states. Using a small region of super-enhancers driving ADRN or MES cell states upstream of a minimal promoter and green fluorescent protein (GFP), these reporters show promise in well-established cell lines. Four reporters were created, two specific to ADRN cells and two specific to MES cells. Validation of these reporters using flow cytometry, western blot analysis, and qPCR showed that MES reporters were robust and specific, while ADRN were constitutively active in both cell sates. Additionally, these reporters were tested in patient-derived cell lines. Preliminary data shows that the MES reporters may also function in these lines. From these studies, we anticipate determining the cell population resistant to chemotherapeutics and identify the cell state that drives tumor recurrence. There is a drastic need for understanding the cellular makeup and features of relapsed NBL tumors. These studies are designed to determine how the tumors repopulate and may lead to a novel way to treat relapsed NBL tumors. Citation Format: Samantha Turk, Melody Allensworth, Justina McEvoy, Marybeth Lupo, Jackie Norrie, Michael A. Dyer. Novel reporter tool for visualization of neuroblastoma cell state abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 698.