| Literature DB >> 27177180 |
Haiyan Wang1, Shanbao Cai1,2, Barbara J Bailey1, M Reza Saadatzadeh1,3, Jixin Ding1,3, Eva Tonsing-Carter1,4,5, Taxiarchis M Georgiadis6, T Zachary Gunter6, Eric C Long6, Robert E Minto6, Kevin R Gordon6, Stephanie E Sen6, Wenjing Cai1, Jacob A Eitel7, David L Waning4,8, Lauren R Bringman9, Clark D Wells9, Mary E Murray1, Jann N Sarkaria10, Lawrence M Gelbert1, David R Jones11, Aaron A Cohen-Gadol4,3, Lindsey D Mayo1,4, Harlan E Shannon1, Karen E Pollok1,4,5.
Abstract
OBJECTIVE Improvement in treatment outcome for patients with glioblastoma multiforme (GBM) requires a multifaceted approach due to dysregulation of numerous signaling pathways. The murine double minute 2 (MDM2) protein may fulfill this requirement because it is involved in the regulation of growth, survival, and invasion. The objective of this study was to investigate the impact of modulating MDM2 function in combination with front-line temozolomide (TMZ) therapy in GBM. METHODS The combination of TMZ with the MDM2 protein-protein interaction inhibitor nutlin3a was evaluated for effects on cell growth, p53 pathway activation, expression of DNA repair proteins, and invasive properties. In vivo efficacy was assessed in xenograft models of human GBM. RESULTS In combination, TMZ/nutlin3a was additive to synergistic in decreasing growth of wild-type p53 GBM cells. Pharmacodynamic studies demonstrated that inhibition of cell growth following exposure to TMZ/nutlin3a correlated with: 1) activation of the p53 pathway, 2) downregulation of DNA repair proteins, 3) persistence of DNA damage, and 4) decreased invasion. Pharmacokinetic studies indicated that nutlin3a was detected in human intracranial tumor xenografts. To assess therapeutic potential, efficacy studies were conducted in a xenograft model of intracranial GBM by using GBM cells derived from a recurrent wild-type p53 GBM that is highly TMZ resistant (GBM10). Three 5-day cycles of TMZ/nutlin3a resulted in a significant increase in the survival of mice with GBM10 intracranial tumors compared with single-agent therapy. CONCLUSIONS Modulation of MDM2/p53-associated signaling pathways is a novel approach for decreasing TMZ resistance in GBM. To the authors' knowledge, this is the first study in a humanized intracranial patient-derived xenograft model to demonstrate the efficacy of combining front-line TMZ therapy and an inhibitor of MDM2 protein-protein interactions.Entities:
Keywords: APE1 = apurinic/apyrimidinic endonuclease I; ATM = ataxia-telangiectasia mutated; BER = base excision repair; BSA = bovine serum albumin; DNA repair; FBS = fetal bovine serum; GAPDH = glyceraldehyde-3-phosphate-dehydrogenase; GBM = glioblastoma; IUSCC, IUSM = Indiana University Simon Cancer Center, Indiana University School of Medicine; MDM2; MDM2 = murine double minute 2; MDM2 inhibitor; MGMT = O6-methylguanine DNA methyltransferase; MS = mass spectroscopy; NSG = NOD.Cg-PrkdcscidIL2rgtm1Wjl/Sz; PBS = phosphate-buffered saline; PK = pharmacokinetic; PPI = protein–protein interaction; S15 = phosphorylation on serine 15-p53; T/N = combination of TMZ and nutlin3a; TBS = Tris-buffered saline; TBST = TBS and Tween 20; TMZ = temozolomide; combination therapy; glioblastoma; oncology; p53; patient-derived xenograft; temozolomide
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Year: 2016 PMID： 27177180 PMCID： PMC5280578 DOI： 10.3171/2016.1.JNS152513
Source DB: PubMed Journal: J Neurosurg ISSN： 0022-3085 Impact factor: 5.115