ABSTRACT
Estrogen receptor (ER) plays important roles in regulating normal development and female reproductive system function. Loss of ER pathway activity is a hallmark of breast cancer progression, associated with accelerated tumor proliferation and resistance to endocrine therapy. How ER loss occurs remains poorly understood. Here, we show that serine starvation, a metabolic stress often found in solid tumors, downregulates estrogen receptor alpha (ERα) expression, represses transcriptional targets such as progesterone receptor (PR), and reduces sensitivity to antiestrogens, suggesting a transition of ER-positive (ER+) breast cancer cells to an ER/PR-negative (ER-/PR-) state. ER downregulation under serine starvation is accompanied by a global loss of histone acetylation. These chromatin changes are driven by metabolic reprogramming triggered by serine starvation, particularly lower glucose flux through glycolysis and the TCA cycle, leading to reduced acetyl-CoA levels and histone hypoacetylation. Supplementation with acetate or glycerol triacetate (GTA), precursors of acetyl-CoA, restores H3K27 acetylation and ERα expression under serine starvation. Therefore, a major consequence of serine starvation in breast cancer could be global chromatin changes that influence lineage-specific gene expression.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Financial Support: This work was supported by a NIH T32 Training Grant (CA009302-40) to A.M.L., and an American Cancer Society Research Scholar Grant (RSG-20-036-01) and a Stanford Maternal and Child Health Research Institute Research Scholar Award (2020) to J.Y.