YTHDF2 iCLIP in glioblastoma stem cells

Glioblastoma is a universally lethal cancer driven by glioblastoma stem cells (GSCs). Here, we interrogated N6-methyladenosine (m6A) mRNA modifications in GSCs by methyl RNA-immunoprecipitation followed by sequencing (meRIP-seq) and transcriptome analysis, finding transcripts marked by m6A often upregulated. Interrogating m6A regulators, GSCs displayed preferential expression as well as in vitro and in vivo dependency of the m6A reader, YTHDF2, in contrast to normal neural stem cells (NSCs). While YTHDF2 has been reported to destabilize mRNAs, YTHDF2 stabilized the oncogene transcripts, MYC and VEGFA, in GSCs in an m6A-dependent manner. We identified IGFBP3 as a downstream effector of the YTHDF2-MYC axis in GSCs and IGF1/IGF1R inhibitor, Linsitinib, as preferentially targeting YTHDF2-expressing cells, inhibiting the viability of GSCs without affecting NSCs and impairing in vivo glioblastoma growth. Thus, YTHDF2 links RNA epitranscriptomic modifications and GSC growth, laying the foundation for the YTHDF2-MYC-IGFBP3 axis as a specific and novel therapeutic target in glioblastoma. YTHDF2 iCLIP performed on 2 glioblastoma stem cell lines, and 1 neuronal stem cell line