Activated KRAS reprograms neural progenitor cells to glioma stem cell-like phenotype

Glioma is the most common primary brain tumor. Glioma stem cells (GSCs) are the origin of gliomagenesis and may develop from normal neural progenitor cells (NPCs). However, how neoplastic transformation occurs in normal NPCs and the role of the Ras/Raf/MAPK pathway in NPC transformation is unclear. The present study generated NPCs from human embryonic stem cells (ESCs) carrying gene alterations in the Ras/Raf/MAPK pathway. The CCK-8 proliferation, single-cell clonal expansion, cell migration, RT-qPCR, immunofluorescence staining, western blotting, transcriptome and Seahorse analyses, and intracranial implantation assay were performed to identify the characterization of transformed NPCs in vitro and in vivo. Brain organoids were used to verify the phenotypes transforming in NPCs. KRAS-activated NPCs exhibited increased proliferation and migration in vitro. KRAS-activated NPCs showed atypical morphology and formed aggressive tumors in immunodeficient mice. At the molecular level, KRAS-activated NPCs displayed neoplasm-associated metabolic and gene expression profiles. Moreover, activation of KRAS led to substantial cell proliferation and abnormal structure in ESC-derived brain organoids. The present study showed that activated KRAS transformed normal NPCs to GSC-like cells and established a simple cellular model to investigate gliomagenesis.