New Histone Lactylation Sites Drive Breast Cancer Growth Through Metabolic Loop

This groundbreaking study reveals how breast cancer cells exploit a newly discovered metabolic-epigenetic feedback loop to fuel their growth and spread. Researchers analyzed breast cancer tissues from 234 patients and found significantly elevated levels of protein lactylation—a recently discovered modification where lactate from cellular metabolism attaches to proteins.

The team identified two previously unknown histone lactylation sites: H4K79 and H4K91. These modifications were dramatically increased in cancer tissues compared to normal breast tissue and correlated with worse patient prognosis. Using advanced proteomics and genomics techniques, they mapped how these modifications regulate gene expression.

The key discovery is a self-reinforcing cycle: cancer cells rely heavily on glycolysis (sugar breakdown) which produces lactate. This lactate then modifies histones H4K79 and H4K91, which act like molecular switches to turn on genes for glycolytic enzymes including LDHA, PGK1, and HK1. These enzymes accelerate glycolysis further, creating more lactate and perpetuating the cycle.

When researchers blocked this cycle using glycolysis inhibitors, cancer cells showed reduced growth, migration, and invasion. The enzyme P300 was identified as the "writer" that adds lactyl groups to these histone sites. This research provides compelling evidence that targeting this metabolic-epigenetic loop could offer new therapeutic approaches for breast cancer treatment.

The findings bridge two major cancer hallmarks—metabolic reprogramming and epigenetic alterations—showing how they work together rather than independently to drive cancer progression.