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Kallay L, Keskin H, Ross A, Rupji M, Moody OA, Wang X, Li G, Ahmed T, Rashid F, Stephen MR, Cottrill KA, Nuckols TA, Xu M, Martinson DE, Tranghese F, Pei Y, Cook JM, Kowalski J, Taylor MD, Jenkins A, Pomeranz Krummel DA, Sengupta S. Modulating native GABA A receptors in medulloblastoma with positive allosteric benzodiazepine-derivatives induces cell death. J Neurooncol 2019; 142:411-422. [PMID: 30725256 PMCID: PMC6478651 DOI: 10.1007/s11060-019-03115-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 01/31/2019] [Indexed: 02/07/2023]
Abstract
PURPOSE Pediatric brain cancer medulloblastoma (MB) standard-of-care results in numerous comorbidities. MB is comprised of distinct molecular subgroups. Group 3 molecular subgroup patients have the highest relapse rates and after standard-of-care have a 20% survival. Group 3 tumors have high expression of GABRA5, which codes for the α5 subunit of the γ-aminobutyric acid type A receptor (GABAAR). We are advancing a therapeutic approach for group 3 based on GABAAR modulation using benzodiazepine-derivatives. METHODS We performed analysis of GABR and MYC expression in MB tumors and used molecular, cell biological, and whole-cell electrophysiology approaches to establish presence of a functional 'druggable' GABAAR in group 3 cells. RESULTS Analysis of expression of 763 MB tumors reveals that group 3 tumors share high subgroup-specific and correlative expression of GABR genes, which code for GABAAR subunits α5, β3 and γ2 and 3. There are ~ 1000 functional α5-GABAARs per group 3 patient-derived cell that mediate a basal chloride-anion efflux of 2 × 109 ions/s. Benzodiazepines, designed to prefer α5-GABAAR, impair group 3 cell viability by enhancing chloride-anion efflux with subtle changes in their structure having significant impact on potency. A potent, non-toxic benzodiazepine ('KRM-II-08') binds to the α5-GABAAR (0.8 µM EC50) enhancing a chloride-anion efflux that induces mitochondrial membrane depolarization and in response, TP53 upregulation and p53, constitutively phosphorylated at S392, cytoplasmic localization. This correlates with pro-apoptotic Bcl-2-associated death promoter protein localization. CONCLUSION GABRA5 expression can serve as a diagnostic biomarker for group 3 tumors, while α5-GABAAR is a therapeutic target for benzodiazepine binding, enhancing an ion imbalance that induces apoptosis.
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Affiliation(s)
- Laura Kallay
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| | - Havva Keskin
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| | - Alexandra Ross
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| | - Manali Rupji
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA
| | - Olivia A Moody
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Xin Wang
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Canada
- Developmental & Stem Cell Biology Program, The Hospital for Sick Children, Toronto, Canada
| | - Guanguan Li
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Taukir Ahmed
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Farjana Rashid
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Michael Rajesh Stephen
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Kirsten A Cottrill
- Molecular and Systems Pharmacology Graduate Training Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA, USA
| | - T Austin Nuckols
- Molecular and Systems Pharmacology Graduate Training Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA, USA
| | - Maxwell Xu
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Deborah E Martinson
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA
| | - Frank Tranghese
- Electrical and Computer Engineering Department, Boston University, Boston, MA, USA
| | - Yanxin Pei
- Center for Cancer and Immunology Research, Brain Tumor Institute, Children's National Medical Center, Washington, DC, USA
| | - James M Cook
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Jeanne Kowalski
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA
- Department of Biostatistics & Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Michael D Taylor
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Canada
- Developmental & Stem Cell Biology Program, The Hospital for Sick Children, Toronto, Canada
- Division of Neurosurgery, The Hospital for Sick Children, Toronto, Canada
| | - Andrew Jenkins
- Departments of Anesthesiology & Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Daniel A Pomeranz Krummel
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA.
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA.
- Winship Cancer Institute, Emory University Hospital, 1365C Clifton Road, Suite C5086, Atlanta, GA, USA.
| | - Soma Sengupta
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA.
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA.
- Department of Hematology & Medical Oncology, Emory University School of Medicine, Atlanta, GA, USA.
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA.
- Winship Cancer Institute, Emory University Hospital, 1365C Clifton Road, Suite C5086, Atlanta, GA, USA.
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