Epstein-Barr Virus-Driven B-Cell Transformation under Germinal Center Hypoxia Requires External Unsaturated Fatty Acids

TL;DR

This study shows how Epstein-Barr virus transforms B-cells in low-oxygen environments and depends on external unsaturated fatty acids for growth.

Contribution

The first ex vivo model of EBV-driven B-cell transformation under hypoxia is developed, revealing novel metabolic dependencies.

Findings

EBV-driven B-cell transformation under hypoxia activates oncogenic super-enhancers like MYC.

Hypoxically transformed B-cells rely on external unsaturated fatty acids rather than fatty acid synthesis.

These cells upregulate glycerophospholipid metabolism and lipid droplet formation to manage saturated lipids.

Abstract

Epstein-Barr virus (EBV) contributes to over 200,000 cancers annually, predominantly aggressive lymphomas originating from hypoxic germinal centers (< 1% O2). However, conventional models fail to recapitulate the physiologically relevant hypoxic microenvironment which profoundly influences B-cell metabolic remodeling during transformation. Here, we establish an ex vivo model of EBV-driven B-cell transformation under 1% O2, demonstrating robust transformation and super-enhancer activation of oncogenic regulators, including MYC. Multi-omic analyses reveal distinct metabolic adaptations to hypoxia. Unlike normoxic B-cells, which rely on fatty acid desaturases and oxidation to mitigate lipotoxicity, hypoxically transformed B-cells suppress fatty acid synthesis while upregulating glycerophospholipid metabolism and lipid droplet formation to buffer excess saturated lipids. Consequently, these cells exhibit heightened dependence on external unsaturated fatty acids to support proliferation. Our findings provide the first physiologically relevant ex vivo model of EBV-driven B-cell transformation under hypoxia, uncovering metabolic vulnerabilities that could inform targeted therapeutic strategies for EBV-associated malignancies.

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