m6A demethylase ALKBH5 restrains migration and invasion and Wnt signaling pathway activity of gastric cancer cells

Objective To investigate the effect of RNA demethylase ALKBH5 on migration and invasion of gastric cancer (GC) cells and its potential mechanism. Methods Cancer Genome Atlas (TCGA) was employed to determine the correlation of ALKBH5 expression variations with overall survival (OS) in GC patients (n=371). The mouse models of orthotopic transplantation and metastasis were established to evaluate the correlation of between ALKBH5 expression and GC cells metastasis. After ALKBH5 knockdown and overexpression cells were constructed, the effect of ALKBH5 on migration and invasion of GC cells was explored with Transwell chamber assay. Furthermore, m6AVAR online database (http://m6Avar.renlab.org/index.html) was used to predict the m6A modification sites of Wnt activating targets; Western blotting and quantitative real-time PCR (qRT-PCR) combined with actinomycin D were applied to detect the protein expression and mRNA stability of downstream targets in Wnt signaling pathway. Results TCGA analysis showed that GC patients with lower ALKBH5 expression had shorter OS time. In vivo experiments confirmed that the low expression of ALKBH5 was involved in the distant metastasis of GC cells, and knockdown of ALKBH5 promoted the migration and invasion of GC cells. m6A modification sites were found in the mRNAs of Wnt downstream targets MYC, CD44 and c-Met, and the absence of ALKBH5 indicated increased protein expression and mRNA stability of these molecules. Conclusion The loss of ALKBH5 expression promotes the migration and invasiveness of GC cells and sustains the activation of Wnt signaling pathway.