A Preclinical Model of Malignant Peripheral Nerve Sheath Tumor-like Melanoma Is Characterized by Infiltrating Mast Cells.
Human melanomas exhibit considerable genetic, pathologic, and microenvironmental heterogeneity. Genetically engineered mice have successfully been used to model the genomic aberrations contributing to melanoma pathogenesis, but their ability to recapitulate the phenotypic variability of human disease and the complex interactions with the immune system have not been addressed. Here, we report the unexpected finding that immune cell-poor pigmented and immune cell-rich amelanotic melanomas developed simultaneously in Cdk4R24C-mutant mice upon melanocyte-specific conditional activation of oncogenic BrafV600E and a single application of the carcinogen 7,12-dimethylbenz(a)anthracene. Interestingly, amelanotic melanomas showed morphologic and molecular features of malignant peripheral nerve sheath tumors (MPNST). A bioinformatic cross-species comparison using a gene expression signature of MPNST-like mouse melanomas identified a subset of human melanomas with a similar histomorphology. Furthermore, this subset of human melanomas was found to be highly associated with a mast cell gene signature, and accordingly, mouse MPNST-like melanomas were also extensively infiltrated by mast cells and expressed mast cell chemoattractants similar to human counterparts. A transplantable mouse MPNST-like melanoma cell line recapitulated mast cell recruitment in syngeneic mice, demonstrating that this cell state can directly reconstitute the histomorphologic and microenvironmental features of primary MPNST-like melanomas. Our study emphasizes the importance of reciprocal, phenotype-dependent melanoma-immune cell interactions and highlights a critical role for mast cells in a subset of melanomas. Moreover, our BrafV600E-Cdk4R24C model represents an attractive system for the development of therapeutic approaches that can target the heterogeneous tumor microenvironment characteristic of human melanomas.
Unit for RNA Biology, Department of Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn, Germany. thomas.tueting@ukb.uni-bonn.de michael.hoelzel@ukb.uni-bonn.de.
Michael
M
Hölzel
Laboratory of Experimental Dermatology, Department of Dermatology and Allergy, University of Bonn, Bonn, Germany.
Jennifer
J
Landsberg
Laboratory of Experimental Dermatology, Department of Dermatology and Allergy, University of Bonn, Bonn, Germany.
Nicole
N
Glodde
Laboratory of Experimental Dermatology, Department of Dermatology and Allergy, University of Bonn, Bonn, Germany.
Tobias
T
Bald
Laboratory of Experimental Dermatology, Department of Dermatology and Allergy, University of Bonn, Bonn, Germany.
Meri
M
Rogava
Unit for RNA Biology, Department of Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn, Germany.
Stefanie
S
Riesenberg
Section of Translational Epileptology, Department of Neuropathology, University of Bonn, Bonn, Germany.
Albert
A
Becker
Department of Oncology and Pathology, Clinical Sciences, Lund University, Lund, Sweden.
Göran
G
Jönsson
Laboratory of Experimental Dermatology, Department of Dermatology and Allergy, University of Bonn, Bonn, Germany. thomas.tueting@ukb.uni-bonn.de michael.hoelzel@ukb.uni-bonn.de.
Thomas
T
Tüting
D000818:Animals; D045744:Cell Line, Tumor; D015331:Cohort Studies; D015870:Gene Expression; D006801:Humans; D008407:Mast Cells / Q000378:metabolism*; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D046228:Microarray Analysis; D018317:Nerve Sheath Neoplasms / Q000378:metabolism* / Q000473:pathology; D010524:Peripheral Nervous System Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology