Metabolic stress is a barrier to Epstein–Barr virus-mediated B-cell immortalization

Abstract

Epstein-Barr virus (EBV) is an oncogenic herpesvirus that has been causally linked to the development of B-cell and epithelial malignancies. Early after infection, EBV induces a transient period of hyperproliferation that is suppressed by the activation of the DNA damage response and a G1/S-phase growth arrest. This growth arrest prevents long-term outgrowth of the majority of infected cells. We developed a method to isolate and characterize infected cells that arrest after this early burst of proliferation and integrated gene expression and metabolic profiling to gain a better understanding of the pathways that attenuate immortalization. We found that the arrested cells have a reduced level of mitochondrial respiration and a decrease in the expression of genes involved in the TCA cycle and oxidative phosphorylation. Indeed, the growth arrest in early infected cells could be rescued by supplementing the TCA cycle. Arrested cells were characterized by an increase in the expression of p53 pathway gene targets, including sestrins leading to activation of AMPK, a reduction in mTOR signaling, and, consequently, elevated autophagy that was important for cell survival. Autophagy was also critical to maintain early hyperproliferation during metabolic stress. Finally, in assessing the metabolic changes from early infection to long-term outgrowth, we found concomitant increases in glucose import and surface glucose transporter 1 (GLUT1) levels, leading to elevated glycolysis, oxidative phosphorylation, and suppression of basal autophagy. Our study demonstrates that oncogene-induced senescence triggered by a combination of metabolic and genotoxic stress acts as an intrinsic barrier to EBV-mediated transformation.Epstein-Barr virus | oncogene-induced senescence | autophagy | B cell | metabolism

Epstein-Barr Virus-Encoded Latent Membrane Protein 1 Upregulates Glucose Transporter 1 Transcription via the mTORC1/NF-κB Signaling Pathways

“…STF-31, used in this study, is one of the promising Glut-1 inhibitors which have been shown to selectively kill renal carcinoma cells (25,43). Interestingly, there are reports showing that high glucose levels also enhance virus infection of host cells, supporting viral replication and maintenance of latency infection (44)(45)(46). Activation of Glut-1 transcription is a novel property of LMP1 not previously reported.…”

The role of metabolic checkpoint regulators in B cell survival and transformation

“…Growth arrested cells have been shown to increase the expression of sestrins leading to AMPK activation and mTORC1 inhibition. 73 Activation of these metabolic stress-signaling pathways suggests that the cells failed to satisfy their high metabolic demands. Providing the cells with cell-permeable metabolites has been shown to increase the number of proliferating cells, demonstrating that metabolic stress contributes to limiting EBV-mediated replicative capacity.…”

Autophagy and Viral Infection

“…It has also been reported that human gamma-herpesvirus 4 (Epstein-Barr virus, EBV) employ several strategies to interact with autophagic proteins and favor their own survival [23,90,123]. Specific autophagy inhibitors are able to encourage EBV lytic replication and might very well influence its oncogenesis [32].…”