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Grit, J.

Publications and source records attributed to Grit, J..

2 recordsLinked to original sources

Reciprocal inflammatory signaling in an ex-vivo explant model for neurofibromatosis type 1-related cutaneous neurofibromas

Cutaneous neurofibromas (CNF) are benign tumors that occur in the dermis of individuals with neurofibromatosis type 1 (NF), an inherited tumor predisposition syndrome. CNFs cause disfigurement, pain, burning, and itching, resulting in reduced quality of life in NF patients. However, due to their benign nature there are few in vitro or in vivo models of CNFs, which has limited the research of CNF biology and drug discovery efforts. To address this, we developed a patient derived explant (PDE) ex vivo culture model of CNF tumors and normal skin from NF patients. CNF PDEs remain viable in culture for over 9 days and recapitulate the cellular composition and molecular signaling of CNFs. We identified reciprocal inflammatory signaling in CNF PDEs, in which tumors rely on either prostaglandin or leukotriene mediated signaling pathways. Ex vivo glucocorticoid treatment reduced expression of pro-inflammatory genes, confirming CNF PDEs are a useful model for mechanistic studies and preclinical drug testing.

cell biology↗

Genomic MET amplification occurs early in NF1-related malignant peripheral nerve sheath tumor (MPNST) progression and is a potent therapeutic target

Malignant Peripheral Nerve Sheath Tumors (MPNSTs) are highly resistant sarcomas that occur in up to 13% of individuals with Neurofibromatosis Type 1 (NF1). Genomic analysis of longitudinally collected tumor samples in a case of MPNST disease progression revealed early hemizygous microdeletions in NF1 and TP53, with concomitant amplifications of MET, HGF, and EGFR. To examine the role of MET in MPNST progression, we developed mice with enhanced MET expression and NF1 ablation (NF1fl/KO;lox-stop-loxMETtg/+;Plp-creERTtg/+; referred to as NF1-MET). NF1-MET mice express a robust MPNST phenotype in the absence of additional mutations. A comparison of NF1-MET MPSNTs with MPNSTs derived from NF1KO/+;p53R172H;Plp-creERTtg/+ (NF1-P53) and NF1KO/+;Plp-creERTtg/+ (NF1) mice revealed unique Met, Ras, and PI3K signaling patterns. To investigate the therapeutic potential of MET inhibition among tumorgrafts derived from the respective MPNST models, we tested the highly selective MET inhibitor, capmatinib. NF1-MET MPNSTs were uniformly sensitive to MET inhibition whereas only a small subset of NF1-P53 and NF1 MPNSTs were inhibited. These results confirm that MET activation is sufficient for Schwann cell dedifferentiation into MPNSTs in the context of NF1 deficiency. RAS-MET signal interactions may be an important driver of MPSNT disease progression.

cancer biology↗