# Post-Translational Control of TET Function in Lymphoma

> **NIH VA I01** · SOUTH TEXAS VETERANS HEALTH CARE SYSTEM · 2022 · —

## Abstract

TET DNA hydroxylases are alpha-ketoglutarate (αKG)-dependent enzymes that catalyze the oxidation of 5mC
to 5-hydroxymethylcytosine (5hmC), thus promoting DNA demethylation. Mapping of 5hmC marks at single base
resolution demonstrated that the main role of TET enzymes is to maintain gene enhancers hypomethylated and
active. Enhancers are genomic areas to which transcription factors bind to modulate gene expression programs.
Hyperactive clusters of enhancers that are densely occupied by transcriptional factors are termed super-
enhancers and are typically found in cancer. Like promoters, enhancers/super-enhancers are regulated by their
DNA methylation status, a process that often goes awry in cancer. Thus, given that active enhancers and super-
enhancers are oncogenic in nature, and that TET enzymes maintain them hypomethylated and active, we
postulate that increased TET activity may itself be oncogenic. Mitochondria function as signaling organelles by
generating substrates that fuel epigenetic changes, including for example acetylation and methylation of DNA
and histones, respectively. Recently, we and others described a subtler interplay between mitochondria and
epigenetics, wherein the levels of the intermediate metabolites αKG and 2-hydroxyglutarate were found to
modulate the activity of TET enzymes, thus controlling DNA methylation. These findings led us to hypothesize
that intermediary metabolism plays as an important role in the control of DNA methylation. Specifically, we
posited that the mitochondrial enzymes D-2- and L-2-hydroxyglutarate dehydrogenase (D2HGDH and
L2HGDH), which catalyze the interconversion of 2-HG to αKG, are integral to the cross talk between
mitochondrial metabolism, TET function and super-enhancer demethylation/activation. To expand on this initial
concept, we sought to identify upstream signals that regulate D2HGDH and L2HGDH expression and,
consequently, influence TET function and enhancer methylation/activity. Using reporter and ChIP assays,
inducible cell lines and mouse models, we recently reported that MYC transcriptionally activates D2HGDH and
L2HGDH and, in a D2HGDH/L2HGDH/αKG-dependent manner, induces TET function leading to DNA
demethylation in vitro and in vivo. Remarkably, we discovered that the MYC/D2-L2HGDH/αKG axis also
promotes the nuclear accumulation of TET1, TET2 and TET3, in association with enhanced O-GlcNAcylation, a
post-translational modification executed by another mitochondrial enzyme, O-GlcNAc transferase (OGT).
Further, we preliminarily showed that in in diffuse large B cell lymphoma (DLBCL), MYC levels associated with
enhancer methylation and target gene expression. Together, these data uncovered a novel mitochondrial
signaling axis which includes MYC at the proximal point, D2/L2HGDH and OGT at the center, and, distally, TET
activity and subcellular location. In this proposal, we will use human B cell lymphoma models in vitro and in vivo,
to test the overarching hypothesis that intermediary...

## Key facts

- **NIH application ID:** 10251482
- **Project number:** 2I01BX001882-09
- **Recipient organization:** SOUTH TEXAS VETERANS HEALTH CARE SYSTEM
- **Principal Investigator:** Ricardo C Aguiar
- **Activity code:** I01 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2022
- **Award amount:** —
- **Award type:** 2
- **Project period:** 2013-04-01 → 2026-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10251482

## Citation

> US National Institutes of Health, RePORTER application 10251482, Post-Translational Control of TET Function in Lymphoma (2I01BX001882-09). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10251482. Licensed CC0.

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