Serine/threonine/tyrosine-interacting-like protein 1 (STYXL1), a pseudo phosphatase, promotes oncogenesis in glioma

Abstract Phosphatases play an important role in cellular signaling and are often found dysregulated in cancers including glioblastoma (GBM). A comprehensive bioinformatics analysis of phosphatases (n = 403) in multiple datasets revealed their deregulation in GBM. Among the differentially regulated phosphatases (n = 186; 46.1%), majority of them were found to be regulated by microRNA (n = 94; 50.5%) followed by DNA methylation (n = 22; 11.8%) and altered copy number variation (n = 10; 5.37%). STYXL1 (Serine/threonine/tyrosine-interacting-like protein 1) was found to be the second most amplified gene in GBM, upregulated, and correlated to poor prognosis. The expression of STYXL1 was also found to be higher in IDH1 mutant gliomas and G-CIMP- gliomas which are reported to be more aggressive than their corresponding counterparts. Silencing STYXL1 inhibited glioma cell growth, soft agar colony formation, migration, invasion, proliferation, and xenograft tumor growth. Further, ectopic expression of STYXL1 was found to promote glioma cell growth, soft agar colony formation, migration, and RasV12 induced in-vitro transformation of immortalized human astrocytes, thus confirming its oncogenic potential in GBM. In this report, we provide a comprehensive overview of deregulation of phosphatases in GBM and demonstrate for the first time, the oncogenic nature of STYXL1 in GBM. This study might be useful for treatment of GBM patients with deregulated STYXL1.