Rip-seq of MTR4 in PLC/PRF5

Metabolic switch from oxidative phosphorylation to glycolysis is required for tumorigenesis by providing cancer cells with energy and substrates of biosynthesis, and also plays a key role in inducing immune suppressive tumor microenvironment that inhibits tumor immunotherapy. Therefore, to develop more effective cancer therapy, it is important to elucidate mechanisms that control cancer metabolic switch. MTR4 is a RNA helicase associated with nuclear exosome that plays key roles in RNA processing and surveillance. We demonstrated that MTR4 is frequently overexpressed in hepatocellular carcinoma (HCC) and this predicts poor prognosis of HCC patients. MTR4 is required for HCC tumorigenesis by maintaining cancer metabolic switch. Mechanistically, MTR4 is required for the expression of critical glycolytic proteins such as GLUT1 and PKM2 by binding to their pre-mRNA and ensuring correct alternative splicing. c-Myc binds to the promoter of MTR4 gene and is required for MTR4 expression, indicating that MTR4 is a key mediator of c-Myc function in promoting cancer metabolism. These findings reveal an important pathway to drive cancer metabolic switch and present MTR4 as a promising therapeutic target for treating HCC. Analysis of RIP-seq RNA data enabled the identification of the MTR4 binding sites in the PLC/PRF5 cell transcriptome.