The m6A Demethylase ALKBH5 Maintains Tumorigenicity of Glioblastoma Stem-Like Cells by Sustaining FOXM1 Expression and Cell Proliferation Programing

The dynamic and reversible N6-methyladenosine (m6A) RNA modification installed and erased by N6-methyltransferases and demethylases regulates gene expression and cell fate. Here, we show that the m6A demethylase ALKBH5 is highly expressed in glioblastoma stem-like cells (GSCs). Silencing ALKBH5 suppresses the proliferation of patient-derived GSCs in vitro and in vivo. Integrated transcriptome and m6A-seq analyses revealed altered expression of select ALKBH5 target genes, including FOXM1, a critical transcription factor for the ALKBH5-dependent cell cycle gene expression. ALKBH5 binds to and demethylates FOXM1 nascent transcripts, leading to enhanced FOXM1 expression. Further, a long noncoding RNA antisense to the FOXM1 (FOXM1-AS) interacts with ALKBH5 and FOXM1 nascent transcripts and promotes their interaction. Depleting ALKBH5 and FOXM1-AS disrupted GSC tumorigenesis through the FOXM1 axis. Our work uncovers a novel function for ALKBH5 in maintaining GSC tumorigenicity and provides insight into critical roles of the m6A RNA methylation in human brain tumor. m6A-seq and anti-m6A RIP-seq of mRNA from control and shALKBH5 cells