Fatty acid-induced CD36 expression via O-GlcNAcylation drives gastric cancer metastasis

Metastasis is the primary cause of death in patients with advanced cancer. Recently, a high-fat diet was shown to specifically promote the metastatic potential of specific cancer cells in a CD36-dependent manner. However, the molecular basis of the fatty acid (FA)-induced upregulation of CD36 has remained unclear. Methods: RT-qPCR, FACS analysis, immunoblotting and immunohistochemistry, as well as retrieving TCGA database, were carried out to quantitate CD36 expression in gastric cancer (GC) tissues and cell lines. Transwell assay and xenografts were used to assess cell metastasis abilities in vitro and in vivo after indicated treatment. Luciferase reporter assay was carried out to evaluate the changes in signaling pathways when O-GlcNAcylation level was increased in GC cells and in vitro O-GlcNAcylation assay was utilized for wild and mutant types of CD36 protein to explore the potential O-GlcNAcylation sites. Results: High CD36 expression is a predictor of poor survival and promotes metastasis of GC cells and the use of neutralizing antibodies to block CD36 inhibits GC metastasis in mice. FA or a HFD promotes the metastatic potential of GC cells by upregulating CD36 via increasing the O-GlcNAcylation level. Increased O-GlcNAcylation levels promote the transcription of CD36 by activating the NF-kappa B pathway and also increase its FA uptake activity by directly modifying CD36 at S468 and T470. Conclusion: FA-induced hyper-O-GlcNAcylation promotes the transcription and function of CD36 by activating the NF-kappa B pathway and directly modifying CD36 at S468 and T470, which drives GC metastasis.