Browsing by Author "Masters, Andrea"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Brigatinib causes tumor shrinkage in both NF2-deficient meningioma and schwannoma through inhibition of multiple tyrosine kinases but not ALK
    (PLOS, 2021-07-15) Chang, Long-Sheng; Oblinger, Janet L.; Smith, Abbi E.; Ferrer, Marc; Angus, Steven P.; Hawley, Eric; Petrilli, Alejandra M.; Beauchamp, Roberta L.; Riecken, Lars Björn; Erdin, Serkan; Poi, Ming; Huang, Jie; Bessler, Waylan K.; Zhang, Xiaohu; Guha, Rajarshi; Thomas, Craig; Burns, Sarah S.; Gilbert, Thomas S.K.; Jiang, Li; Li, Xiaohong; Lu, Qingbo; Yuan, Jin; He, Yongzheng; Dixon, Shelley A.H.; Masters, Andrea; Jones, David R.; Yates, Charles W.; Haggarty, Stephen J.; La Rosa, Salvatore; Welling, D. Bradley; Stemmer-Rachamimov, Anat O.; Plotkin, Scott R.; Gusella, James F.; Guinney, Justin; Morrison, Helen; Ramesh, Vijaya; Fernandez-Valle, Cristina; Johnson, Gary L.; Blakeley, Jaishri O.; Clapp, D. Wade; Pediatrics, School of Medicine
    Neurofibromatosis Type 2 (NF2) is an autosomal dominant genetic syndrome caused by mutations in the NF2 tumor suppressor gene resulting in multiple schwannomas and meningiomas. There are no FDA approved therapies for these tumors and their relentless progression results in high rates of morbidity and mortality. Through a combination of high throughput screens, preclinical in vivo modeling, and evaluation of the kinome en masse, we identified actionable drug targets and efficacious experimental therapeutics for the treatment of NF2 related schwannomas and meningiomas. These efforts identified brigatinib (ALUNBRIG®), an FDA-approved inhibitor of multiple tyrosine kinases including ALK, to be a potent inhibitor of tumor growth in established NF2 deficient xenograft meningiomas and a genetically engineered murine model of spontaneous NF2 schwannomas. Surprisingly, neither meningioma nor schwannoma cells express ALK. Instead, we demonstrate that brigatinib inhibited multiple tyrosine kinases, including EphA2, Fer and focal adhesion kinase 1 (FAK1). These data demonstrate the power of the de novo unbiased approach for drug discovery and represents a major step forward in the advancement of therapeutics for the treatment of NF2 related malignancies.
  • Thumbnail Image
    Item
    PAK1 inhibition reduces tumor size and extends the lifespan of mice in a genetically engineered mouse model of Neurofibromatosis Type 2 (NF2)
    (Oxford University Press, 2021) Hawley, Eric; Gehlhausen, Jeffrey; Karchugina, Sofiia; Chow, Hoi-Yee; Araiza-Olivera, Daniela; Radu, Maria; Smith, Abbi; Burks, Ciersten; Jiang, Li; Li, Xiaohong; Bessler, Waylan; Masters, Andrea; Edwards, Donna; Burgin, Callie; Jones, David; Yates, Charles; Clapp, D. Wade; Chernoff, Jonathan; Park, Su-Jung; Biochemistry and Molecular Biology, School of Medicine
    Neurofibromatosis Type II (NF2) is an autosomal dominant cancer predisposition syndrome in which germline haploinsufficiency at the NF2 gene confers a greatly increased propensity for tumor development arising from tissues of neural crest derived origin. NF2 encodes the tumor suppressor, Merlin, and its biochemical function is incompletely understood. One well-established function of Merlin is as a negative regulator of group A serine/threonine p21-activated kinases (PAKs). In these studies we explore the role of PAK1 and its closely related paralog, PAK2, both pharmacologically and genetically, in Merlin-deficient Schwann cells and in a genetically engineered mouse model (GEMM) that develops spontaneous vestibular and spinal schwannomas. We demonstrate that PAK1 and PAK2 are both hyper activated in Merlin-deficient murine schwannomas. In preclinical trials, a pan Group A PAK inhibitor, FRAX-1036, transiently reduced PAK1 and PAK2 phosphorylation in vitro, but had insignificant efficacy in vivo. NVS-PAK1-1, a PAK1 selective inhibitor, had a greater but still minimal effect on our GEMM phenotype. However, genetic ablation of Pak1 but not Pak2 reduced tumor formation in our NF2 GEMM. Moreover, germline genetic deletion of Pak1 was well tolerated, while conditional deletion of Pak2 in Schwann cells resulted in significant morbidity and mortality. These data support the further development of PAK1-specific small molecule inhibitors and the therapeutic targeting of PAK1 in vestibular schwannomas and argue against PAK1 and PAK2 existing as functionally redundant protein isoforms in Schwann cells.