Noncanonical activation of GLI signaling in SOX2+ cells drives medulloblastoma relapse

Sci Adv. 2022 Jul 22;8(29):eabj9138. doi: 10.1126/sciadv.abj9138. Epub 2022 Jul 20.

Abstract

SRY (sex determining region Y)-box 2 (SOX2)-labeled cells play key roles in chemoresistance and tumor relapse; thus, it is critical to elucidate the mechanisms propagating them. Single-cell transcriptomic analyses of the most common malignant pediatric brain tumor, medulloblastoma (MB), revealed the existence of astrocytic Sox2+ cells expressing sonic hedgehog (SHH) signaling biomarkers. Treatment with vismodegib, an SHH inhibitor that acts on Smoothened (Smo), led to increases in astrocyte-like Sox2+ cells. Using SOX2-enriched MB cultures, we observed that SOX2+ cells required SHH signaling to propagate, and unlike in the proliferative tumor bulk, the SHH pathway was activated in these cells downstream of Smo in an MYC-dependent manner. Functionally different GLI inhibitors depleted vismodegib-resistant SOX2+ cells from MB tissues, reduced their ability to further engraft in vivo, and increased symptom-free survival. Our results emphasize the promise of therapies targeting GLI to deplete SOX2+ cells and provide stable tumor remission.

MeSH terms

  • Brain Neoplasms*
  • Cerebellar Neoplasms* / genetics
  • Child
  • Hedgehog Proteins / metabolism
  • Humans
  • Medulloblastoma* / genetics
  • Medulloblastoma* / pathology
  • Neoplasm Recurrence, Local
  • SOXB1 Transcription Factors / genetics
  • SOXB1 Transcription Factors / metabolism
  • Signal Transduction
  • Zinc Finger Protein GLI1 / metabolism

Substances

  • GLI1 protein, human
  • Hedgehog Proteins
  • SOX2 protein, human
  • SOXB1 Transcription Factors
  • Zinc Finger Protein GLI1