A CD133-AKT-Wnt signaling axis drives glioblastoma brain tumor-initiating cells.

Mechanistic insight into signaling pathways downstream of surface receptors has been revolutionized with integrated cancer genomics. This has fostered current treatment modalities, namely immunotherapy, to capitalize on targeting key oncogenic signaling nodes downstream of a limited number of surface markers. Unfortunately, rudimentary mechanistic understanding of most other cell surface proteins has reduced the clinical utility of these markers. CD133 has reproducibly been shown to correlate with disease progression, recurrence, and poor overall survivorship in the malignant adult brain tumor, glioblastoma (GBM). Using several patient-derived CD133high and CD133low GBMs we describe intrinsic differences in determinants of stemness, which we owe to a CD133-AKT-Wnt signaling axis in which CD133 functions as a putative cell surface receptor for AKT-dependent Wnt activation. These findings may have implications for personalized oncology trials targeting PI3K/AKT or Wnt as both pathways may be activated independent of their canonical drivers, leading to treatment resistance and disease relapse.