Contributed Talk

Magnetic resonance elastography and cell and nucleus shape analysis in zebrafish neuroblastoma models

Mareike Wolff¹, Jakob Jordan², Tom Meyer², Julia Köppke¹, Pablo Gottheil³, Heloise Bustin², Josef Käs³, Angelika Eggert¹, Ingolf Sack², Anja Heeren-Hagemann¹

Contact: 

Neuroblastoma is the most common malignant solid tumor in children, arising from the sympathoadrenal lineage of the neural crest. It is one of the most devastating childhood cancers, accounting for 15% of all cancer-related deaths in children. Treatment of high-risk MYCN amplified neuroblastoma remains challenging. As a cost- and space-efficient preclinical neuroblastoma model, different transgenic zebrafish lines with MYCN-driven neuroblastoma have been established that show a high comparability to human disease [1]. Biochemical properties of neuroblastoma cells have been comprehensively investigated, including the involvement of mechanotransduction signaling in tumor progression. However, the biophysical and mechanical properties of neuroblastomas and their metastases have not yet been systematically characterized. We are currently starting to fill this knowledge gap by using magnetic resonance elastography (MRE) to measure tissue stiffness in tumor bearing zebrafish and high-risk neuroblastoma patients. We could recently show that micro MRE (µMRE) in zebrafish is a feasible method for the analysis of viscoelastic properties of tiny MYCN-driven fish-tumors [2].

Building on this prior work, we are now analyzing potential differences in viscoelasticity of tumors arising from different genetic backgrounds at different anatomical sites starting with two MYCN-driven transgenic zebrafish lines with and without additional LMO1 expression in the sympathoadrenal lineage. LMO1 overexpression was shown to lead to a more aggressive tumor progression in patients and in MYCN fish [1] while we observe a second site of primary tumor development.

In this study, we show by µMRE that tumors developed in the main tumor location share the same viscoelastic properties irrespective their genotype. However, tumors at the LMO1-specific second site of primary tumor growth show a decrease in stiffness by 10% to those at the main tumor location with a significance of p= 0.03. To further understand these results, we assessed cell motility based on nuclear shape analysis combined with nuclei shape clustering. First results show an increase of nucleus size for the LMO1-specific site of primary tumor development, which will be promising to follow up on [3]. Additionally, we will further explore the intertumoral heterogeneity using both µMRE stiffness maps as well as shape maps from nuclei shape clustering. Moreover, we plan to use an antibody staining to assess the proliferative state of the studied tumors, as an indicator for tumor progression. With this study, we aim to understand the biomechanical property changes in neuroblastoma which drive tumor progression.