# Targeting neuroblastoma cell state plasticity

> **NIH NIH P01** · CHILDREN'S HOSP OF PHILADELPHIA · 2024 · $624,652

## Abstract

PROJECT 1 SUMMARY/ABSTRACT
Epigenetic mechanisms drive normal development and unsurprisingly play critical roles in the pathogenesis and
treatment of neuroblastoma (NB), an embryonal neoplasm and the most common pediatric extracranial solid
tumor. Epigenetic plasticity has also emerged as an important mechanism of therapy resistance. Adrenergic
(ADR) and mesenchymal (MES) epigenetic states in NB cells are defined by differences in super-enhancer
landscapes and transcriptional programs. The MES state is associated with resistance to both chemotherapy
and targeted therapy, including resistance to inhibitors of the ALK tyrosine kinase receptor. We discovered that
the MES state is also associated with impaired responses to the immunotherapy dinutuximab, an FDA-approved
antibody directed against GD2, a glycolipid on the surface of NB cells. We found in vitro and in vivo, that
downregulation of GD2 is a major mechanism of resistance to GD2-directed therapies. We now propose multiple
approaches to study and target the MES state by pursuing strategies to manipulate the targets of current
therapies (e.g., GD2/dinutuximab) and by identifying liabilities present in MES NB cells. To this end, we
conducted a genome-scale CRISPR screen to identify genes that regulate surface GD2 levels in NB. Multiple
chromatin regulators scored, including all three members of the PRC2 complex (polycomb proteins EED and
SUZ12 and histone-lysine N-methyltransferase EZH2) and MEN1 encoding menin, a scaffolding protein that
interacts with the histone methyltransferases KMT2A/B (MLL1/2). We have already confirmed that the EZH2
inhibitor (EZH2-i) tazemetostat increases GD2 levels on NB cells in vitro and in vivo, improving preclinical
responses to dinutuximab. We hypothesize that chromatin modifying compounds will differentiate MES
NB models into an ADR-like state, thereby increasing expression of targets critical to both small
molecule inhibitors and to immunotherapies, leading to enhanced responses. In parallel, we have
conducted genome-scale CRISPR-Cas9 screens to identify gene dependencies enriched in the MES versus
ADR states, and we will profile the peptides presented on MHC (immunopeptidome) in MES versus ADR cells
to identify additional targets for immunotherapies. We will deploy genetic and chemical genetic approaches and
develop novel and much needed isogenic, immunocompetent, genetically engineered mouse models (GEMM)
of MES and ADR NB to test this hypothesis.
Aim 1. Develop and characterize isogenic immunocompetent models of ADR versus MES NB.
Aim 2. Test the hypothesis that epigenetic modulators can increase expression of immunotherapy
targets in NB.
Aim 3. Identify novel combination therapeutic approaches to target the NB MES state.
The ultimate deliverable will be nomination of combination therapies with GD2- or other targeted treatments to
be tested by the NANT in children with NB.
1

## Key facts

- **NIH application ID:** 10768923
- **Project number:** 2P01CA217959-06A1
- **Recipient organization:** CHILDREN'S HOSP OF PHILADELPHIA
- **Principal Investigator:** WILLIAM A WEISS
- **Activity code:** P01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $624,652
- **Award type:** 2
- **Project period:** 2017-09-18 → 2029-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10768923

## Citation

> US National Institutes of Health, RePORTER application 10768923, Targeting neuroblastoma cell state plasticity (2P01CA217959-06A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10768923. Licensed CC0.

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