- Browse by Subject
Browsing by Subject "neurofibroma"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Correction: Expanding the clinical phenotype of individuals with a 3-bp in-frame deletion of the NF1 gene (c.2970_2972del): an update of genotype–phenotype correlation(Elsevier, 2019-03) Koczkowska, Magdalena; Callens, Tom; Gomes, Alicia; Sharp, Angela; Chen, Yunjia; Hicks, Alesha D.; Aylsworth, Arthur S.; Azizi, Amedeo A.; Basel, Donald G.; Bellus, Gary; Bird, Lynne M.; Blazo, Maria A.; Burke, Leah W.; Cannon, Ashley; Collins, Felicity; DeFilippo, Colette; Denayer, Ellen; Digilio, Maria C.; Dills, Shelley K.; Dosa, Laura; Greenwood, Robert S.; Griffis, Cristin; Gupta, Punita; Hachen, Rachel K.; Hernández-Chico, Concepción; Janssens, Sandra; Jones, Kristi J.; Jordan, Justin T.; Kannu, Peter; Korf, Bruce R.; Lewis, Andrea M.; Listernick, Robert H.; Lonardo, Fortunato; Mahoney, Maurice J.; Ojeda, Mayra Martinez; McDonald, Marie T.; McDougall, Carey; Mendelsohn, Nancy; Miller, David T.; Mori, Mari; Oostenbrink, Rianne; Perreault, Sebastién; Pierpont, Mary Ella; Piscopo, Carmelo; Pond, Dinel A.; Randolph, Linda M.; Rauen, Katherine A.; Rednam, Surya; Rutledge, S. Lane; Saletti, Veronica; Schaefer, G. Bradley; Schorry, Elizabeth K.; Scott, Daryl A.; Shugar, Andrea; Siqveland, Elizabeth; Starr, Lois J.; Syed, Ashraf; Trapane, Pamela L.; Ullrich, Nicole J.; Wakefield, Emily G.; Walsh, Laurence E.; Wangler, Michael F.; Zackai, Elaine; Claes, Kathleen B.M.; Wimmer, Katharina; van Minkelen, Rick; De Luca, Alessandro; Martin, Yolanda; Legius, Eric; Messiaen, Ludwine M.; Neurology, School of MedicinePurpose: Neurofibromatosis type 1 (NF1) is characterized by a highly variable clinical presentation, but almost all NF1-affected adults present with cutaneous and/or subcutaneous neurofibromas. Exceptions are individuals heterozygous for the NF1 in-frame deletion, c.2970_2972del (p.Met992del), associated with a mild phenotype without any externally visible tumors. Methods: A total of 135 individuals from 103 unrelated families, all carrying the constitutional NF1 p.Met992del pathogenic variant and clinically assessed using the same standardized phenotypic checklist form, were included in this study. Results: None of the individuals had externally visible plexiform or histopathologically confirmed cutaneous or subcutaneous neurofi- bromas. We did not identify any complications, such as sympto-matic optic pathway gliomas (OPGs) or symptomatic spinal neurofibromas; however, 4.8% of individuals had nonoptic brain tumors, mostly low-grade and asymptomatic, and 38.8% had cognitive impairment/learning disabilities. In an individual with the NF1 constitutional c.2970_2972del and three astrocytomas, we provided proof that all were NF1-associated tumors given loss of heterozygosity at three intragenic NF1 microsatellite markers and c.2970_2972del. Conclusion: We demonstrate that individuals with the NF1 p.Met992del pathogenic variant have a mild NF1 phenotype lacking clinically suspected plexiform, cutaneous, or subcutaneous neurofi-bromas. However, learning difficulties are clearly part of the phenotypic presentation in these individuals and will require specialized care.Item Hyperactive RAS/PI3-K/MAPK Signaling Cascade in Migration and Adhesion of Nf1 Haploinsufficient Mesenchymal Stem/Progenitor Cells(MDPI, 2015-06) Zhou, Yuan; He, Yongzheng; Sharma, Richa; Xing, Wen; Estwick, Selina A.; Wu, Xiaohua; Rhodes, Steven D.; Xu, Mingjiang; Yang, Feng-Chun; Department of Pediatrics, Indiana University School of MedicineNeurofibromatosis type 1 (NF1) is an autosomal dominant disease caused by mutations in the NF1 tumor suppressor gene, which affect approximately 1 out of 3000 individuals. Patients with NF1 suffer from a range of malignant and nonmalignant manifestations such as plexiform neurofibromas and skeletal abnormalities. We previously demonstrated that Nf1 haploinsufficiency in mesenchymal stem/progenitor cells (MSPCs) results in impaired osteoblastic differentiation, which may be associated with the skeletal manifestations in NF1 patients. Here we sought to further ascertain the role of Nf1 in modulating the migration and adhesion of MSPCs of the Nf1 haploinsufficient (Nf1+/−) mice. Nf1+/− MSPCs demonstrated increased nuclear-cytoplasmic ratio, increased migration, and increased actin polymerization as compared to wild-type (WT) MSPCs. Additionally, Nf1+/− MSPCs were noted to have significantly enhanced cell adhesion to fibronectin with selective affinity for CH271 with an overexpression of its complimentary receptor, CD49e. Nf1+/− MSPCs also showed hyperactivation of phosphoinositide 3-kinase (PI3-K) and mitogen activated protein kinase (MAPK) signaling pathways when compared to WT MSPCs, which were both significantly reduced in the presence of their pharmacologic inhibitors, LY294002 and PD0325901, respectively. Collectively, our study suggests that both PI3-K and MAPK signaling pathways play a significant role in enhanced migration and adhesion of Nf1 haploinsufficient MSPCs.Item Preclinical assessments of the MEK inhibitor PD-0325901 in a mouse model of neurofibromatosis type 1.(Wiley, 2015-10) Jousma, Edwin; Rizvi, Tilat A.; Wu, Jianqiang; Janhofer, David; Dombi, Eva; Dunn, Richard S.; Kim, Mi-Ok; Masters, Andrea R.; Jones, David R.; Cripe, Timothy P.; Ratner, Nancy; Department of Medicine, IU School of MedicineBackground: Neurofibromatosis type 1 (NF1) is a genetic disorder that predisposes affected individuals to formation of benign neurofibromas, peripheral nerve tumors that can be associated with significant morbidity. Loss of the NF1 Ras-GAP protein causes increased Ras-GTP, and we previously found that inhibiting MEK signaling downstream of Ras can shrink established neurofibromas in a genetically engineered murine model. Procedures: We studied effects of MEK inhibition using 1.5 mg/kg/day PD-0325901 prior to neurofibroma onset in the Nf1 flox/flox;Dhh-Cre mouse model. We also treated mice with established tumors at 0.5 and 1.5 mg/kg/day dosees of PD-0325901. We monitored tumor volumes using MRI and volumetric measurements, and measured pharmacokinetic and pharmacodynamic endpoints. Results: Early administration significantly delayed neurofibroma development as compared to vehicle controls. When treatment was discontinued neurofibromas grew, but no rebound effect was observed and neurofibromas remained significantly smaller than controls. Low dose treatment of mice with PD-0325901 resulted in neurofibroma shrinkage equivalent to that observed at higher doses. Tumor cell proliferation decreased, although less than at higher doses with drug. Tumor blood vessels per area correlated with tumor shrinkage. Conclusions: Neurofibroma development was not prevented by MEK inhibition, beginning at 1 month of age, but tumor size was controlled by early treatment. Moreover, treatment with PD-0325901 at very low doses may shrink neurofibromas while minimizing toxicity. These studies highlight how genetically engineered mouse models can guide clinical trial design.