FOXO3-mediated chemo-protection in high-stage neuroblastoma depends on wild-type TP53 and SESN3

Oncogene. 2017 Nov 2;36(44):6190-6203. doi: 10.1038/onc.2017.288. Epub 2017 Sep 4.

Abstract

Forkhead box O class transcription factors are homeostasis regulators that control cell death, longevity and therapy-resistance. In neuroblastoma (NB), nuclear FOXO3 correlates with stage M disease and poor prognosis. To analyze whether FOXO3 contributes to drug-resistance in this childhood cancer, we investigated how different high-stage-derived NB cells respond to the activation of an ectopic FOXO3 allele. We found endogenous FOXO3 mostly localized to the nucleus-upon activation of an ectopic, 4OHT-activated FOXO3(A3)ER fusion protein two of the cell lines underwent apoptosis, whereas in the others FOXO3-activation even increased survival during drug-treatment. In the latter cell type, FOXO3 did not induce the BH3-only protein BCL2L11/BIM due to impaired binding of FOXO3 to the BIM-promoter, but still activated other FOXO3 targets. It was shown before that FOXO3 and TP53 physically interact with each other at two different regions-the TP53-N-terminus binds to the FOXO3-DNA binding domain (DBD) and the FOXO3-C-terminus interacts with the TP53-DBD. Interestingly, cell lines that undergo FOXO3-induced cell death carry homozygous point mutations in the TP53-DBD near the structural hotspot-mutation-site R175H, which abrogated FOXO3-TP53 interaction. In contrast, in FOXO3-death-resistant cells no point mutations in the TP53-DBD were found-in these cells FOXO3-TP53 complexes are formed and FOXO3-binding to the BIM-promoter, but not the induction of the detoxifying protein SESN3, were prevented, which in turn increased chemo-protection in this type of high-stage-derived NB cells. Our combined data suggest that FOXO3 steps in as a death inducer in case of TP53-mutation, whereas functional TP53 alters FOXO3-target-promoter-recognition, which prevents death induction by FOXO3 and instead increases chemo-protection and survival of NB cells. This novel mechanism may explain the low incidence of TP53 mutation in high-stage NB at diagnosis and suggests FOXO3 as a therapeutic target for this childhood malignancy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / genetics
  • Bcl-2-Like Protein 11 / genetics*
  • Cell Line, Tumor
  • Cell Nucleus / genetics
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Drug Resistance, Neoplasm / genetics
  • Forkhead Box Protein O3 / genetics*
  • Forkhead Box Protein O3 / metabolism
  • Heat-Shock Proteins / genetics*
  • Heat-Shock Proteins / metabolism
  • Humans
  • Mutation
  • Neoplasm Staging
  • Neuroblastoma / drug therapy
  • Neuroblastoma / genetics*
  • Neuroblastoma / pathology
  • Promoter Regions, Genetic
  • Protein Binding
  • Tumor Suppressor Protein p53 / genetics*
  • Tumor Suppressor Protein p53 / metabolism

Substances

  • BCL2L11 protein, human
  • Bcl-2-Like Protein 11
  • DNA-Binding Proteins
  • FOXO3 protein, human
  • Forkhead Box Protein O3
  • Heat-Shock Proteins
  • SESN3 protein, human
  • TP53 protein, human
  • Tumor Suppressor Protein p53