Abstract LB226: FGFR2 modulates ALK inhibition response in high-risk neuroblastoma
Authors: Pucci Perla , Barrett Charlotte , Trigg Ricky , Jahangiri Leila , Matthews Jamie D. , Mologni Luca , Burke G. A. Amos , Turner Suzanne D 
Published: April 2023

Abstract
High-risk neuroblastoma (NB) has a poor prognosis despite multimodal treatment. To improve survival and minimise treatment side-effects, research has focused on developing more effective therapeutic strategies. Anaplastic lymphoma kinase (ALK) is a promising druggable target as its expression rapidly decreases in healthy tissues postnatally, and it is expressed as a hyperactivated mutant form in ~14% of high-risk NB. The ALK tyrosine kinase inhibitor lorlatinib is a promising treatment, but resistance has been reported, hindering long-term benefits. With a trimodal approach, consisting of genome-wide CRISPR-Cas9-overexpression (CRISPRa) screens, RNA sequencing and high-throughput drug screens, we have identified genes whose expression is associated with decreased sensitivity to lorlatinib creating novel therapeutic vulnerabilities. In particular, we validate the CRISPRa screen hit FGFR2 as a bypass signalling mechanism desensitising mutant ALK-expressing NB cells to lorlatinib; overexpression of FGFR2 increased, while silencing decreased resistance of NB cells to lorlatinib. Furthermore, RNA sequencing of lorlatinib resistant (LR) NB cells developed in our lab, compared to parental cell lines, showed FGFR2 to be expressed to a higher level in the LR cells. High-throughput drug screens exposing LR and parental NB cell lines to an FDA-approved drug library of 1430 compounds showed that drugs targeting receptor tyrosine kinases, including FGFR2, were amongst the compounds most significantly effective in reducing the viability of LR NB cells compared to parental cells. The multi-kinase inhibitor ponatinib and the selective FGFR inhibitor erdafitinib acted synergistically with lorlatinib in treating both parental and LR NB cells although both inhibitors were more effective in inhibiting the growth of LR compared to parental cells when given alone, suggesting that FGFR2 may represent a novel vulnerability to treat lorlatinib resistant NB. In vivo studies using patient-derived xenograft (PDX) models of high-risk NB (MYCN-amplified and ALKF1174L mutant) showed that combinations of either ponatinib or erdafitinib with lorlatinib decreased tumour growth and increased survival compared to PDXs treated with vehicle or either agent alone. In conclusion, these findings suggest that FGFR2 alters NB sensitivity to lorlatinib and modulation of this pathway in combination with ALK inhibition is a promising approach to improve NB treatment response and ultimately patient survival.
Citation Format: Perla Pucci, Charlotte Barrett, Ricky Trigg, Leila Jahangiri, Jamie D. Matthews, Luca Mologni, G. A. Amos Burke, Suzanne D Turner. FGFR2 modulates ALK inhibition response in high-risk neuroblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB226.