# Ataluren‐Induced Functional Restoration of Neurofibromin in Fibroblasts From Neurofibromatosis Type 1 Patients With Nonsense Mutations

## TL;DR

This study shows that ataluren can restore neurofibromin function in some patients with Neurofibromatosis Type 1 caused by nonsense mutations, and identifies new biomarkers and a potential therapeutic target.

## Contribution

The study identifies AMPD3 and TGFBR3 as novel biomarkers for NF1 therapy and highlights AMPD3 as a new therapeutic target.

## Key findings

- Ataluren treatment alleviated hyperactivated RAS in 23% of NF1NS/+ fibroblasts.
- Phosphorylated ERK levels decreased in 24% of ataluren-treated cells.
- AMPD3 and TGFBR3 were identified as feasible biomarkers for monitoring functional neurofibromin.

## Abstract

Neurofibromatosis Type 1 (NF1) is an autosomal dominant genetic disorder caused by heterogeneous mutations in the tumor suppressor gene NF1. Neurofibromin, encoded by NF1, predominantly acts as a negative regulator of the RAS‐MEK signaling pathway. Up to 30% of NF1 patients harbor nonsense mutations (NS) that introduce premature termination codons (PTCs). Ataluren is a well‐characterized small molecule that acts as a nonsense suppressor by enhancing the ribosomal readthrough of PTCs. Here, we isolated primary fibroblasts from 22 Korean NF1NS/+
patients and comprehensively evaluated the efficacy of ataluren treatment. The results demonstrate that hyperactivated GTP‐bound RAS was significantly alleviated in approximately 23% of NF1NS/+
fibroblasts, and the cellular levels of phosphorylated ERK also decreased in approximately 24% after ataluren treatment. Through transcriptome‐wide profiling based on ataluren responsiveness, we analyzed a subset of genes in ataluren‐treated NF1NS/+
fibroblasts whose expression was significantly altered in ataluren‐responsive cells, but not in nonresponsive cells. Furthermore, both AMPD3 and TGFBR3 were notably identified as feasible biomarkers for monitoring functional neurofibromin. Interestingly, AMPD3 can be an effective therapeutic target for NF1‐associated diseases. Together, our study suggests that ataluren can be considered a therapeutic agent for some NF1NS/+
patients and contributes to expanding insights into NF1 therapy.

The therapeutic potential of ataluren for NF1 nonsense mutations was assessed by a comprehensive evaluation of the RAS/MEK/ERK pathway activity in 22 NF1NS/+
patient‐derived fibroblasts. The whole‐transcriptomic profiles between ataluren responders and nonresponders, and further analysis and validation revealed novel biomarkers, AMPD3 and TGFBR3, for monitoring NF1 therapy and highlighted AMPD3 as a new therapeutic target for NF1‐associated diseases.