ALKBH5 promotes gastric cancer angiogenesis by stabilizing LncRNA PVT1 and VEGFA RNAs via m6A demethylation

AlkB homolog 5 (ALKBH5) has been implicated in tumor progression, however, its specific role in angiogenesis in gastric cancer (GC) and the underlying mechanisms remain poorly understood. Messenger RNA (mRNA) expression levels of vascular endothelial growth factor A (VEGFA), ALKBH5, and long non-coding RNA PVT1 (lncRNA PVT1) in GC and paracancerous tissues were measured by quantitative real-time polymerase chain reaction (qRT-PCR). RNA sequencing (RNA-seq) was employed to identify downstream effectors of lncRNA PVT1. The effects of ALKBH5 and lncRNA PVT1 on angiogenesis were examined in vitro and in vivo. The impact of ALKBH5 on the stability of lncRNA PVT1 and VEGFA RNAs was evaluated by mRNA stability assays, and interactions between ALKBH5 and these RNAs were validated using methylated RNA immunoprecipitation (MeRIP) assay. A significant positive correlation was observed among ALKBH5, lncRNA PVT1, and VEGFA expression in both The Cancer Genome Atlas (TCGA) GC database and sixty GC tissue samples. ALKBH5 and lncRNA PVT1 enhanced angiogenesis in AGS and HS746T cells both in vitro and in vivo. RNA-seq revealed that lncRNA PVT1 upregulated VEGFA mainly through the IL17RA/STAT3 signaling pathway. Additionally, ALKBH5 was found to stabilize both lncRNA PVT1 and VEGFA RNAs. MeRIP assays confirmed the direct binding of ALKBH5 to specific sites on lncRNA PVT1 and VEGFA RNAs. In conclusion, ALKBH5 promotes GC angiogenesis primarily through its m6A demethylase activity on targets such as lncRNA PVT1, which regulates VEGFA expression by modulating IL17RA/STAT3 signaling axis. ALKBH5 may serve as a promising biomarker and therapeutic target in GC.