Nuclear perturbations following adenovirus infection

Spatial and temporal proteome dynamics of glioma cells during oncolytic adenovirus Delta-24-RGD infection

Glioblastoma multiforme (GBM) is the most common and aggressive type of malignant glioma. Oncolytic adenoviruses are being modified to exploit the aberrant expression of proteins in tumor cells to increase the antiglioma efficacy. E1A mutant adenovirus Delta-24-RGD (DNX-2401) has shown a favorable toxicity profile and remarkable efficacy in a first-in-human phase I clinical trial. However, the comprehensive modulation of glioma metabolism in response to Delta-24-RGD infection is poorly understood. Integrating mass spectrometry based-quantitative proteomics, physical and functional interaction data, and biochemical approaches, we conducted a cell-wide study of cytosolic, nuclear, and secreted glioma proteomes throughout the early time course of Delta-24-RGD infection. In addition to the severe proteostasis impairment detected during the first hours post-infection (hpi), Delta-24-RGD induces a transient inhibition of signal transducer and activator of transcription 3 (STAT3), and transcription factor AP-1 (c-JUN) between 3 and 10hpi, increasing the nuclear factor kappa B (NF-κB) activity at 6hpi. Furthermore, Delta-24-RGD specifically modulates the activation dynamics of protein kinase C (PKC), extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 mitogen-activated protein kinase (p38 MAPK) pathways early in infection. At extracellular level, Delta-24-RGD triggers a time -dependent dynamic production of multitasking cytokines, and chemotactic factors, suggesting potential pleiotropic effects on the immune system reactivation. Taken together, these data help us to understand the mechanisms used by Delta-24-RGD to exploit glioma proteome organization. Further mining of this proteomic resource may enable design and engineering complementary adenoviral based-vectors to increase the specificity and potency against glioma.

Nucleolar protein upstream binding factor is sequestered into adenovirus DNA replication centres during infection without affecting RNA polymerase I location or ablating rRNA synthesis

When human adenovirus infects human cells there is disruption of rRNA biogenesis. This report examines the effect of adenovirus infection on the nucleolar protein, upstream binding factor (UBF) which plays a major role in regulating rRNA synthesis. We determined that early after infection, UBF associates with the replication of viral DNA, preferentially associating with the ends of the linear viral genome, and that addition of anti-UBF serum to in vitro replication assays markedly reduced viral DNA replication. Regions of UBF important to these observations are also established. Interestingly, sequestering the majority of UBF from the nucleolus did not lead to the ablation of rRNA synthesis or the sequestration of RNA pol I. In infected cells the bulk of RNA synthesis was RNA pol I associated and distinct from the location of most of the detectable UBF. We propose that UBF plays a role in viral DNA replication, further strengthening the role of nucleolar antigens in the adenovirus life cycle.