Comparative ASCL1 interactome analysis reveals CDK2-Cyclin A2 as suppressors of differentiation in MYCN-amplified neuroblastoma.

Abstract:: UNLABELLED: Neuroblastoma is a heterogeneous pediatric cancer arising from developmentally arrested neuronal precursors, in which restoring differentiation offers therapeutic promise. Achaete-scute homolog 1 (ASCL1), a proneural transcription factor, is widely expressed in neuroblastoma and can drive either proliferation or differentiation depending on the cellular context. In this study, we show that distinct MYCN-amplified neuroblastoma cell lines exhibit differing differentiation responses to ASCL1 overexpression. By comparing genome-wide ASCL1 chromatin binding, transcriptional changes, and protein-protein interactions, we found that ASCL1 binds more extensively to neuronal proteins in a cell line that is more susceptible to ASCL1-driven differentiation but associates with cell-cycle regulators in less responsive cells. We show that cyclin-dependent kinase 2 (CDK2)-cyclin A2 bind ASCL1 in less responsive cells, with CDK-mediated phosphorylation of ASCL1 limiting the ability of ASCL1 to drive differentiation. IMPLICATIONS: Our study reveals that context-dependent interactions of ASCL1 with protein partners on the chromatin control its ability to reengage a differentiation program in neuroblastoma.

Authors:: L Mykhaylechko, RL Gomez, LM Woods, EK Papachristou, R Ramachandran, J Lundie-Brown, R Drummond, D Marcos, FMY Abou Grealy, S Ibragimova, FR Ali, J Carroll, A Philpott

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