Investigating nanoscale chromatin alterations involved in neuroblastoma transformation by optical nanoscopy

Neuroblastoma (NB) is the most common extracranial solid tumor in childhood and is characterized by remarkable heterogeneity. This work aims to characterize changes in chromatin nanoscale architecture being associated with NB transformation. We employed an NB cell line overexpressing the non-coding RNA NDM29, which promotes cell differentiation toward a neuronal phenotype. The nuclear shape, volume and architecture were assessed in both malignant and neuron-like cells by confocal microscopy. Moreover, heterochromatin and euchromatin organization was investigated by stimulated emission depletion (STED) microscopy. The results showed that the nuclei of neuron-like cells have a reduced volume and a more elongated shape compared to those of malignant cells and a different spatial arrangement of euchromatin and heterochromatin. Altogether these data point to an alteration of nuclear organization associated to NB, paving the way towards a better comprehension of the disease. © 2022 Societa Italiana di Fisica. All rights reserved.