Silvestris, D. A., Picardi, E., Cesarini, V., Fosso, B., Mangraviti, N., Massimi, Luca, Martini, Maurizio, Pesole, G., Locatelli, Franco, Gallo, A., Massimi L., Martini M. (ORCID:0000-0002-6260-6310), Locatelli F. (ORCID:0000-0002-7976-3654), Silvestris, D. A., Picardi, E., Cesarini, V., Fosso, B., Mangraviti, N., Massimi, Luca, Martini, Maurizio, Pesole, G., Locatelli, Franco, Gallo, A., Massimi L., Martini M. (ORCID:0000-0002-6260-6310), and Locatelli F. (ORCID:0000-0002-7976-3654)
Background: Adenosine-to-inosine (A-to-I) RNA editing is an essential post-transcriptional mechanism mediated by ADAR enzymes that have been recently associated with cancer. Results: Here, we characterize the inosinome signature in normal brain and de novo glioblastoma (GBM) using new metrics that re-stratify GBM patients according to their editing profiles and indicate this post-transcriptional event as a possible molecular mechanism for sexual dimorphism in GBM. We find that over 85% of de novo GBMs carry a deletion involving the genomic locus of ADAR3, which is specifically expressed in the brain. By analyzing RNA editing and patient outcomes, an intriguing gender-dependent link appears, with high editing of Alus shown to be beneficial only in male patients. We propose an inosinome-based molecular stratification of GBM patients that identifies two different GBM subgroups, INO-1 and INO-2, which can identify novel high-risk gender-specific patient groups for which more aggressive treatments may be necessary. Conclusions: Our data provide a detailed picture of RNA editing landscape in normal brain and GBM, exploring A-to-I RNA editing regulation, disclosing unexpected editing implications for GBM patient stratification and identification of gender-dependent high-risk patients, and suggesting COG3 I/V as an eligible site for future personalized targeted gene therapy.