NUDT21 alters glioma migration through differential alternative polyadenylation of LAMC1

We identified LAMC1 as a critical NUDT21 target involved in several core glioma-driving signaling pathways. qRT-PCR analysis confirmed that NUDT21-knockdown in GBM cells resulted in the preferred usage of the proximal C/PAS of LAMC1. Furthermore, functional studies revealed that NUDT21-knockdown-induced 3’UTR shortening of LAMC1 was sufficient to induce translational gain, as LAMC1 was upregulated in these cells compared to their respective controls. Additionally, we demonstrated that primary glial cells recapitulated this phenomenon. We also further dissected the miRNA-mediated mechanism by which LAMC1 expression was regulated by showing that NUDT21 knockdown in glioma cells directed the 3’UTR shortening of LAMC1, removing binding sites for miR-124/506 and consequently inducing LAMC1 expression. Remarkably, we reported that the knockdown of NUDT21 significantly promoted GBM cell migration and that co-depletion of LAMC1 and NUDT21 abrogated this effect. Lastly, we observed that LAMC1 3’UTR shortening predicted poor prognosis of low- and high-grade glioma patients from The Cancer Genome Atlas. Anti-NUDT21 and scramble shRNA-infected LN229 / U251 human gliablastoma cell lines mRNA 3' end sequencing profiles generated by deep sequencing, in triplicate, using Illumina Nextseq 550.