Quiescent sox2(+) cells drive hierarchical growth and relapse in sonic hedgehog subgroup medulloblastoma

Area of Science:

• Oncology
• Cancer Biology
• Pediatric Neuro-oncology

Background:

• Tumor functional heterogeneity poses a major challenge in developing effective cancer therapies.
• Sonic hedgehog (SHH) subgroup medulloblastoma is a common pediatric brain tumor with a significant unmet need for targeted treatments.

Purpose of the Study:

• To investigate the role of Sox2(+) cells in the propagation and relapse of SHH medulloblastoma.
• To identify therapeutic strategies targeting therapy-resistant cell populations within SHH medulloblastoma.

Main Methods:

• Utilized lineage tracing and cell-specific markers (Sox2, doublecortin, NeuN) to track tumor cell dynamics.
• Administered anti-mitotic chemotherapy and Smoothened inhibitors to assess enrichment of Sox2(+) cells.
• Evaluated the efficacy of mithramycin in targeting Sox2(+) cells and inhibiting tumor growth.

Main Results:

• Quiescent, therapy-resistant Sox2(+) cells were identified as the key drivers of SHH medulloblastoma.
• Sox2(+) cells were enriched after chemotherapy and Smoothened inhibition, forming a reservoir for tumor regrowth.
• Lineage tracing confirmed Sox2(+) cells are responsible for tumor relapse.
• Mithramycin treatment effectively abrogated tumor growth by targeting Sox2(+) cells.

Conclusions:

• Sox2(+) cells propagate SHH medulloblastoma through a mechanism resembling neurogenesis.
• Eliminating Sox2(+) cells is a promising therapeutic paradigm for treating SHH medulloblastoma.
• Addressing tumor functional heterogeneity is crucial for overcoming therapeutic resistance in medulloblastoma.