Cell Reports
Volume 24, Issue 2, 10 July 2018, Pages 463-478.e5
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Article
Opposing Tumor-Promoting and -Suppressive Functions of Rictor/mTORC2 Signaling in Adult Glioma and Pediatric SHH Medulloblastoma

https://doi.org/10.1016/j.celrep.2018.06.050Get rights and content
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Highlights

  • p53-mutant-driven gliomas acquire chromosomal alterations of adult primary GBM

  • Rictor/mTORC2 loss delays glioma formation and prolongs survival

  • Rictor deletion with p53 loss promotes SHH-MB formation from GCPs

  • Low Rictor expression is associated with poor survival of human pediatric SHH-MBs

Summary

Most human cancers arise from stem and progenitor cells by the sequential accumulation of genetic and epigenetic alterations, while cancer modeling typically requires simultaneous multiple oncogenic events. Here, we show that a single p53 mutation, despite causing no defect in the mouse brain, promoted neural stem and progenitor cells to spontaneously accumulate oncogenic alterations, including loss of multiple chromosomal (chr) regions syntenic to human chr10 containing Pten, forming malignant gliomas with PI3K/Akt activation. Rictor/mTORC2 loss inhibited Akt signaling, greatly delaying and reducing glioma formation by suppressing glioma precursors within the subventricular zone stem cell niche. Rictor/mTORC2 loss delayed timely differentiation of granule cell precursors (GCPs) during cerebellar development, promoting sustained GCP proliferation and medulloblastoma formation, which recapitulated critical features of TP53 mutant sonic hedgehog (SHH) medulloblastomas with GLI2 and/or N-MYC amplification. Our study demonstrates that Rictor/mTORC2 has opposing functions in neural stem cells and GCPs in the adult and the developing brain, promoting malignant gliomas and suppressing SHH-medulloblastoma formation, respectively.

Keywords

glioblastoma
medulloblastoma
Rictor
mammalian target of rapamycin complex 2
mTORC2
Pten
p53
phosphatidylinositol 3-kinase pathway
PI3K
Akt

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15

These authors contributed equally

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