Synergistic effect of Nutlin-3 combined with MG-132 on schwannoma cells through restoration of merlin and p53 tumour suppressors.

Abstract

BACKGROUND:

The great majority of sporadic vestibular schwannomas (VSs) are due to the mutations of the NF2 gene encoding merlin. Sporadic VSs exhibit variable growth patterns and only a small fraction of the tumours are fast-growing; however, the underlying mechanisms remain undefined.

METHODS:

DNA sequencing and dosage analysis were used to identify the NF2 mutation status in sporadic schwannomas. The expression and sub-cellular localization of merlin and p53-MDM2 were assessed by immunoblotting, qRT-PCR and immunofluorescence. In vitro and in vivo studies were performed to reveal the effects of Nutlin-3 (a MDM2 inhibitor) and/or MG-132(a proteasome inhibitor) on schwannomas. The proliferation of schwannoma cells was assessed by CCK-8 assay, EdU staining and Flow cytometry analysis.

FINDINGS:

Double genetic hits of NF2 tended to occur in fast-growing tumours, characterized by the absence of merlin. The deregulation of p53-MDM2 was demonstrated to mediate merlin-deficient tumour growth, characterized by a nuclear accumulation of stabilized MDM2, contributing to a nuclear export of p53 for degradation. Nutlin-3 blocked the proliferation of schwannoma cells via a cooperative recovery of merlin and p53, accompanied by the shuttling of both proteins from the cytoplasm to the nucleus. We further demonstrated a difference in the sensitivity to Nutlin-3 between schwannoma cells with and without merlin expression. Nutlin-3 combined with MG-132 narrowed this between-group difference and triggered stronger inhibitory effects on the growth of schwannomas through coordinated reactivation of p53.

INTERPRETATION:

These findings present treatment strategies directed on the pathogenesis of sporadic schwannomas. FUND: National Natural Science Foundation of China.

• Authors: Hongsai Chen, Lu Xue, He Huang, Hantao Wang, Xiaoman Zhang, Weidong Zhu, Zhigang Wang, Zhaoyan Wang, Hao Wu
• Journal: EBioMedicine (EBioMedicine) Vol. 36 Pg. 252-265 (Oct 2018) ISSN: 2352-3964 [Electronic] Netherlands
• PMID: 30274821 (Publication Type: Journal Article)
• Copyright: Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Chemical References

• Antineoplastic Agents
• Imidazoles
• Piperazines
• Tumor Suppressor Protein p53
• nutlin 3
• Proteasome Endopeptidase Complex

Topics

• Animals
• Antineoplastic Agents (pharmacology)
• Cell Line, Tumor
• Cell Survival (drug effects, genetics)
• Disease Models, Animal
• Drug Synergism
• Gene Expression Regulation, Neoplastic
• Genes, Neurofibromatosis 2
• High-Throughput Nucleotide Sequencing
• Humans
• Imidazoles (pharmacology)
• Mice
• Mutation
• Neurilemmoma (genetics, metabolism, pathology)
• Piperazines (pharmacology)
• Proteasome Endopeptidase Complex (metabolism)
• Protein Binding
• Protein Stability
• Proteolysis
• Tumor Suppressor Protein p53 (genetics, metabolism)
• Xenograft Model Antitumor Assays