α-Ketoglutarate-Mediated DNA Demethylation Sustains T-Acute Lymphoblastic Leukemia upon TCA Cycle Targeting

Area of Science:

• Biochemistry
• Oncology
• Cancer Metabolism

Background:

• Metabolism-based therapies are crucial for cancer treatment, but drug resistance is a significant challenge.
• Cancer cells exhibit metabolic plasticity, enabling them to adapt and survive under therapeutic pressure.
• Understanding metabolic rewiring is key to developing effective combination therapies against malignancies.

Purpose of the Study:

• To investigate the metabolic plasticity of T-cell acute lymphoblastic leukemia (T-ALL) cells.
• To elucidate the mechanisms by which T-ALL cells develop resistance to therapies targeting the tricarboxylic acid (TCA) cycle.
• To identify potential therapeutic strategies to overcome drug resistance in T-ALL.

Main Methods:

• Utilized metabolomics flux analysis to study metabolic shifts in T-ALL cells.
• Genetically depleted the dihydrolipoamide-succinyl transferase (DLST), an E2 subunit of the alpha-ketoglutarate dehydrogenase complex (KGDHC).
• Employed zebrafish xenograft models to assess the efficacy of dual pharmacologic inhibition.

Main Results:

• T-ALL cells switch from oxidative decarboxylation to reductive carboxylation when the TCA cycle is disrupted.
• KGDHC dysfunction leads to increased DNA demethylation by alpha-ketoglutarate-dependent dioxygenases (e.g., TET demethylases).
• This metabolic shift enhances the production of isocitrate dehydrogenases (IDH) 1 and 2, contributing to drug resistance.

Conclusions:

• Dysfunction of the alpha-ketoglutarate dehydrogenase complex (KGDHC) drives metabolic rewiring and drug resistance in T-ALL.
• Dual inhibition of the TCA cycle and TET demethylases demonstrates additive efficacy in reducing tumor burden.
• These findings offer insights into T-ALL resistance mechanisms and suggest combination strategies to improve treatment outcomes.