Abstract

Phosphorylated CTD Interacting Factor 1 (PCIF1) is the exclusive methyltransferase responsible for the N6,2-O-dimethyladenosine (m6Am) modification in mammalian mRNA. Our previous research identified PCIF1 as a potent tumor suppressor in glioma, demonstrating its ability to impair cell proliferation, induce G2/M phase arrest, and promote apoptosis. However, its role in glioma cell migration and invasion remains unclear. In this study, we investigate how PCIF1 regulates glioma cell migration and invasion. Overexpression of PCIF1 inhibits migration and invasion, whereas PCIF1 knockdown enhances these behaviors. Corresponding changes are observed in mesenchymal markers (Vimentin, β-catenin, Snail, Slug) and the epithelial marker T-cadherin, indicating that PCIF1 suppresses epithelial-to-mesenchymal transition (EMT)-mediated glioma invasion. Mechanistically, PCIF1 modulates the AKT pathway by promoting proteasomal degradation of AKT while increasing phosphorylated AKT (p-AKT) levels, revealing a complex regulatory mechanism. PCIF1 knockdown upregulates INPP5B, a lipid phosphatase, causing accumulation of PI(3,4)P2 and enhanced AKT activation. Conversely, PCIF1 overexpression increases PI(3,4,5)P3 production, elevating p-AKT levels. This bidirectional regulation suggests that PCIF1 influences phosphoinositide signaling and AKT activation. Our findings highlight PCIF1 as a key modulator of glioblastoma cell migration and invasion through phosphoinositide signaling, positioning it as a potential biomarker and therapeutic target in glioma.