Abstract A02: The epigenetic modifier CHAF1A opposes neuroblastoma differentiation via metabolic reprogramming

Background. Neuroblastoma (NB) arises from embryonal neural crest secondary to a block in differentiation and long-term survival inversely correlates with degree of neuronal differentiation. Metabolic rewiring is an important feature of undifferentiated NB tumors. Interestingly, MYCN down regulation precedes differentiation of NB cells induced by retinoic acid (RA) and genetic MYCN silencing leads to neuronal differentiation. We have recently demonstrated a novel function for the histone chaperone CHAF1A in blocking NB differentiation. CHAF1A is a subunit of the Chromatin Assembly Factor-1 (CAF1), which regulates H3K9-trimethylation and DNA methylation. Methods. Morphological and molecular evaluations of NB differentiation were assessed upon CHAF1A silencing in RA-sensitive and RA-resistant lines by neurite outgrowth assays and Q-PCR for mature neuronal markers. Gene expression profiling of CHAF1A knockdown and control cell lines was performed on the Affymetrix U133+2.0 arrays. GSEA (Gene Set Enrichment Analysis) defined the transcriptional response to CHAF1A silencing in RA sensitive lines. Quantitative-PCR assays were used to validate the most significant enriched metabolic gene sets and MYCN western blotting was performed at different time points after CHAF1A silencing. Results. CHAFIA suppression in MYCN-amplified RA-sensitive and RA-resistant lines results in NB differentiation and inhibition of cell proliferation. CHAF1A silencing significantly (nominal p-value Conclusions. We have shown that differentiation of NB cells upon CHAF1A silencing: 1) induces metabolic reprogramming by decreasing glucose and glutamine uptakes, 2) inhibits cell proliferation, and 3) reduces MYCN protein levels. We hypothesize that CHAF1A plays a critical role in the MYCN-mediated metabolic reprogramming of undifferentiated NB tumors. Future studies will further dissect this link and guide the development of novel differentiating therapies for high-risk NB. Citation Format: Eveline Barbieri, Zaowen Chen, Mirthala Moreno-Smith, Jason M. Shohet. The epigenetic modifier CHAF1A opposes neuroblastoma differentiation via metabolic reprogramming. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A02.