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Osum SH, Coutts AW, Duerre DJ, Tschida BR, Kirstein MN, Fisher J, Bell WR, Delpuech O, Smith PD, Widemann BC, Moertel CL, Largaespada DA, Watson AL. Selumetinib normalizes Ras/MAPK signaling in clinically relevant neurofibromatosis type 1 minipig tissues in vivo. Neurooncol Adv 2021; 3:vdab020. [PMID: 33978635 PMCID: PMC8095338 DOI: 10.1093/noajnl/vdab020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The MEK1/2 inhibitor selumetinib was recently approved for neurofibromatosis type 1 (NF1)-associated plexiform neurofibromas, but outcomes could be improved and its pharmacodynamic evaluation in other relevant tissues is limited. The aim of this study was to assess selumetinib tissue pharmacokinetics (PK) and pharmacodynamics (PD) using a minipig model of NF1. METHODS WT (n = 8) and NF1 (n = 8) minipigs received a single oral dose of 7.3 mg/kg selumetinib. Peripheral blood mononuclear cells (PBMCs), cerebral cortex, optic nerve, sciatic nerve, and skin were collected for PK analysis and PD analysis of extracellular regulated kinase phosphorylation (p-ERK) inhibition and transcript biomarkers (DUSP6 & FOS). RESULTS Key selumetinib PK parameters aligned with those observed in human patients. Selumetinib concentrations were higher in CNS tissues from NF1 compared to WT animals. Inhibition of ERK phosphorylation was achieved in PBMCs (mean 60% reduction), skin (95%), and sciatic nerve (64%) from all minipigs, whereas inhibition of ERK phosphorylation in cerebral cortex was detected only in NF1 animals (71%). Basal p-ERK levels were significantly higher in NF1 minipig optic nerve compared to WT and were reduced to WT levels (60%) with selumetinib. Modulation of transcript biomarkers was observed in all tissues. CONCLUSIONS Selumetinib reduces MAPK signaling in tissues clinically relevant to NF1, effectively normalizing p-ERK to WT levels in optic nerve but resulting in abnormally low levels of p-ERK in the skin. These results suggest that selumetinib exerts activity in NF1-associated CNS tumors by normalizing Ras/MAPK signaling and may explain common MEK inhibitor-associated dermatologic toxicities.
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Affiliation(s)
- Sara H Osum
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA
| | | | | | | | - Mark N Kirstein
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, Minnesota, USA
| | - James Fisher
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, Minnesota, USA
| | - W Robert Bell
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA
- Division of Neuropathology, Department of Lab Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Oona Delpuech
- Oncology R&D, AstraZeneca, Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Paul D Smith
- Oncology R&D, AstraZeneca, Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Brigitte C Widemann
- Pediatric Oncology Branch, Rare Tumor Initiative, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | | | - David A Largaespada
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA
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Ocular bioanalysis: challenges and advancements in recent years for these rare matrices. Bioanalysis 2017; 9:1997-2014. [DOI: 10.4155/bio-2017-0175] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
There are many ocular diseases still presenting unmet medical needs. Therefore, new ophthalmologic drugs are being developed. Bioanalysis of eye compartments (along with plasma and other tissues) is important to determine exposure of the target organ to the drug and to help interpret local pharmacological or toxic effects. This review article identifies several challenges that occur within ocular bioanalysis. They include sample collection and preparation, analytical issues, sourcing control matrix, data interpretation and regulatory requirements. It summarizes how these challenges have been recently addressed, how research has advanced and which questions remain unanswered. Recommendations are made based on the literature and our practical experience within ocular bioanalysis and future perspectives are discussed.
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