Nono is a new adenovirus sensor: implication for virotherapy.

Abstract The median survival for GBM patients is 15 months with a five-year survival rate of less than 10%. Current conventional and experimental treatments, including immune checkpoint blockade, have not improved outcomes in the vast majority of glioma patients. Oncolytic viruses (OVs) are designed to specifically infect and lyse cancer cells to elicit an anti-tumor immune response. In a clinical trial developed by the MDACC team, 20% of GBM patients treated with the oncolytic adenovirus Delta-24-RGD showed complete response and survival longer than three years (NCT00805376). Although these studies have shown that robust immune responses can be invoked using oncolytic virotherapy, the molecular mechanisms underlying OV-mediated anti-tumor immunity remain elusive. Exposure to viruses by innate immune sensors induces protective antiviral immunity. Using bulk RNA sequencing of cells infected with adenovirus we identified the main upstream regulators of the innate immune response including IFN gamma, Interferon responsive genes 3 and 7, and STAT3. However, RNAseq unexpectedly uncovered NONO (Non-POU Domain Containing Octamer Binding) as the most relevant upstream regulator. In agreement with the RNAseq data, Protein analyses demonstrated the upregulation of NONO after adenovirus infection. In addition, immunofluorescence and confocal microscopy examination of the infected cells showed the overexpression and translocation to the nucleus of NONO upon virus infection. We are the first laboratory that has identified NONO as a sensor of adenovirus infection, which may have great significance for the future development of oncolytic viruses. Importantly, we discovered the network of proteins that are upregulated after NONO activation and, finally, we have established that changes in the expression level and subcellular localization of NONO are coincident in time during the infection of cultured cells. Future work is focused on examining the immunomodulatory functions of NONO in adenoviral infected tumors and subsequent generation of NONO-resistant oncolytic adenovirus.