# Glial-to-mesenchymal transition drives malignant progression of plexiform neurofibromas in a mouse model of NF1

Audrey Onfroy, Katarzyna J. Radomska, Laure Lecerf, Bastien Job, Aurélien

Beaude, Laura Sesma-Sanz, Tatiana El Jalkh, Denis Thieffry, Patrick

Charnay, Pierre Wolkenstein, et al.

► To cite this version:

Audrey Onfroy, Katarzyna J. Radomska, Laure Lecerf, Bastien Job, Aurélien Beaude, et al. Glial-to-mesenchymal transition drives malignant progression of plexiform neurofibromas in a mouse model of NF1. 2024 NF Conference, Jun 2024, Brussels, Belgium. 2024. [hal-05055379](https://hal.science/hal-05055379v1)

HAL Id: hal-05055379

https://hal.science/hal-05055379v1

Submitted on 4 May 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
# Glial-to-mesenchymal transition drives malignant progression of plexiform neurofibromas in a mouse model of NF1

Katarzyna J. Radomska<fnref n="1" />, **Audrey Onfroy**<fnref n="1" />,<fnref n="4" />, Laure Lecerf<fnref n="1" />, Bastien Job<fnref n="2" />, Aurélien Beude<fnref n="1" />, Laura Sesma-Sanz<fnref n="3" />, Tatiana El Jalkh<fnref n="1" />, Denis Thieffry<fnref n="4" />, Patrick Charnay<fnref n="4" />, Pierre Wolkenstein<fnref n="1" />,<fnref n="5" />, Nicolas Ortonne<fnref n="1" />,<fnref n="6" />, Fanny Coulpier<fnref n="1" /> and Piotr Topilko<fnref n="1" />

Contact: piotr.topilko@inserm.fr

## 1- UNDERSTAND MPNST DEVELOPMENT

<figure><img src="image_2.png" /></figure>

MPNST are aggressive soft tissue sarcomas with no therapy to date.

➤ The goal of the study was to gain knowledge in the cellular and molecular mechanisms governing malignant transformation using a novel NF1 mouse model.

<figure><img src="image_3.png" /></figure>

Mouse model to study malignant transformation :

* Bi-allelic inactivation of *Nf1* in neural crest-derived boundary cap cells and their derivatives : *Nf1*-KO mice

* *Nf1*-KO mice develop pNFs that spontaneously undergo stepwise progression into MPNST [3]

## 2- MATERIALS

<figure><img src="image_4.png" /></figure>

Characterization of tumors using :

* histological evaluation

* IHC characterization

* single-cell transcriptomic profiling

* whole exome sequencing

## 4- TUMOR CELLS UNDERGO GLIAL-TO-MESENCHYMAL TRANSITION

A

<figure><img src="image_5.png" /></figure>

B

<figure><img src="image_6.png" /></figure>

Transcriptional dynamics of tumor cells.

(A) *Tom+* (*Nf1⁻/⁻*) tumor are extracted, then projected on a UMAP, and are colored based on sample of origin and pseudotime inferred with slingshot.

(B) Single-cell gene expression levels and proteomic validation of selected markers.

➤ During malignant progression, *Nf1* mutant tumor cells undergo **glial-to-mesenchymal transition**, marked by *Sox9* expression.

<figure><img src="image_7.png" /></figure>

Evolution of the transcriptomic profile of tumor cells is conserved between NF1 patients and *Nf1*-KO mice.

## 3- Nf1⁻/⁻ TUMOR CELLS GRADUALLY LOSS THEIR GLIAL IDENTITY AND PROLIFERATE DURING MALIGNANT PROGRESSION

A

<figure><img src="image_8.png" /></figure>

B

<figure><img src="image_9.png" /></figure>

C

➤ Tumors progressively extinguish Schwann cells markers (S100B and SOX10) in *Nf1*-KO mice

➤ Tumor cells change their transcriptomic profile during progression

➤ Nerve fibroblasts signature evolves into cancer-associated fibroblasts between pNF and dyNF

**Spectrum of peripheral nerve sheath tumors (PNST) in *Nf1*-KO mice.**

(A) Sections through pNF, dyNF and MPNST immunolabeled for TOM (tumor cells), S100β and SOX10 (glial lineage). Insets show TOM staining of the corresponding lesions.

(B) Pan PNST transcriptomic atlas assembled from *Nf1*-KO derived pNF (n=2), dyNF (n=10) and MPNST (n=4) datasets. Expression score-based annotation resolved 12 distinct cell populations.

(C) Pan PNST atlas split by tumor type. Cells from complete atlas are shown as light grey background. Note distinct location of fibroblasts and tumor cells between tumor types, indicating distinct transcriptomic profiles.

## 5- GLIAL-TO-MESENCHYMAL TRANSITION PRECEDES *Cdkn2a* LOSS IN TUMOR CELLS

<figure><img src="image_10.png" /></figure>

Genomic characterization of tumor cells from *Nf1*-KO mice and transplanted MPNSTs. Each pair of columns corresponds to the primary MPNST (left) and its associated transplanted (right) tumor. The top line represents the number of SNVs for each tumor. The rows below correspond to CNV loss (blue) and SNV (green), including pathogenic variant (dot).

➤ MPNST can be propagated in nude recipients and GMT preceeds *Cdkn2a* loss in tumor cells.

## 6- RAS SIGNALING PATHWAY IS INVOLVED IN *SOX9* EXPRESSION

* Partial *Sox9* inhibition (shRNA and siRNA) delays tumor growth *in vivo*.

* Screening of a library of 3,500 compounds on tumor cells, using SOX9 as read out identified 12 FDA-approved drugs, all related to the inhibition of Ras pathway.

Representation of molecular targets for top 12 candidate drugs, in relation by Ras signaling pathway.

➤ *Sox9* and Ras pathway are therapeutic targets for treatment of MPNSTs

## 7- SUMMARY AND FUTURE DIRECTIONS

* *Nf1*-KO mice recapitulates malignant transformation

<figure><img src="image_11.png" /></figure>

➤ Insight into the epigenetic events governing early GMT

## ABREVIATIONS

dyNF : dysplastic neurofibroma, including ANNUBP

GMT : glial-to-mesenchymal transition

MPNST : malignant peripheral nerve sheath tumor

pNF : plexiform neurofibroma

PNST : peripheral nerve sheath tumor

## REFERENCES

[1] Beert et al., Genes, Chromosomes & Cancer (2011)

[2] Radomska et al., Cancer Discovery (2019)

[3] Radomska et al. (in preparation)

[4] Sun et al., Cell Stem Cell (2021)

[5] Wu et al., Science Advances (2022)

[6] Rhodes et al., Human Molecular Genetics (2019)

[7] Magallón-Lorenz et al., Human Genetics (2021)

[8] Suppiah et al., Nature Communications (2023)

<footnote n="1">¹Mondor Institute for Biomedical Research, INSERM, Créteil, France</footnote>

<footnote n="2">²Gustave Roussy Institute of Oncology, Villejuif, France</footnote>

<footnote n="3">³National Phenotypic Screening Centre, School of Life Sciences, University of Dundee, Dundee, United Kingdom</footnote>

<footnote n="4">⁴École Normale Supérieure, PSL Research University, CNRS, INSERM, IBENS, Paris, France</footnote>

<footnote n="5">⁵Department of Dermatology, Reference Centre for Neurofibromatoses, Henri-Mondor hospital, AP-HP, Créteil, France</footnote>

<footnote n="6">⁶Department of Pathology, Henri-Mondor hospital, AP-HP, Créteil, France</footnote>

<footnote>Funding : Association Neurofibromatoses et Recklinghausen, Foundation Maladies Rares, Canceropole IDF, ITMO Cancer</footnote>