Retinoic acid and ascorbate synergize to suppress myeloid leukemia via TET2 activation [U-937 5hmC-seq]
Enhancing ten-eleven translocation 2 (TET2) activity through genetic or pharmacologic approaches, such as ascorbate supplementation, can slow myeloid malignancy progression. However, ascorbate alone may be insufficient to fully activate TET2 in malignant cells due to pharmacokinetic constraints and the need for chromatin remodeling to enable effective cellular reprogramming. Here, we identify a novel mechanism to enhance TET2 activity via all-trans retinoic acid (ATRA), which induces retinoic acid receptor alpha (RARA)-mediated TET2 transcription in myeloid leukemia cells and synergizes with ascorbate to promote DNA hydroxymethylation and chromatin remodeling at key myeloid differentiation loci. Using Tet1/2/3-deficient mice and primary human acute myeloid leukemia (AML) models, we show that ATRA plus ascorbate more effectively induces differentiation, inhibits leukemia stem cell self-renewal in a TET2-dependent manner, and sensitizes AML cells to targeted therapies in vivo, leading to improved survival. These findings support the combined use of ATRA and ascorbate as a strategy to enhance TET2 activity for the treatment of myeloid malignancies. Overall design: Enzymatic reduced representation base-resolution 5hmC-seq of U937 cells treated 72hr with 1uM ATRA, 250uM LAA, ATRA+LAA, or vehicle control to determine differential hydroxymethylation status