Background: Neuroblastoma (NB) is a neuroendocrine pediatric tumor and patients with high-risk NB have a survival probability lower than 50% despite treatment. Two distinct cell states are described for NB, an immature more treatment resistant mesenchymal (MES) cell state, and a more differentiated adrenergic (ADR) cell state. This study aims to characterize expression patterns of cell-state specific markers, mainly PHOX2B, in HR-NB models with and without treatment. The long-term goal is to identify treatment strategies targeting chemotherapy resistant cell states.

Methods: With gene expression analysis, immunohistochemistry, immunofluorescence, viability assays of untreated and treated organoids and Western blot PHOX2B could be analyzed in various PDX models with and without other cell state markers such as TH and CD44.

Result: This study demonstrated varied PHOX2B expression across different PDX models and heterogeneity in PDX1, PDX2 and PDX3. ADR markers PHOX2B and TH showed variable protein expression correlated to specific PDX models with highest expression in PDX1 and single isolated cells in PDX2, indicating an intermediate state towards ADR. MES marker CD44 showed the highest protein expression in PDX3R. COJEC treatment and TRPA1i treatment did not induce any shift in cell state, implying that the baseline biological identity of the tumor cells may be a key determinant of treatment response.

Conclusions: Our data suggests that not only treatment drive distinct cell state patterns but the intrinsic biological differences. In future, approaches that include cell state profiling to better classify patients and target MES-like cell populations could lead to improved outcomes for patients with treatment resistant HR-NB.