Yilin Du
- kawaokashinpei3
- 5月13日
- 読了時間: 2分
Selected journal : Nature Metabolism
Extracellular CD44 lactylation impairs CD8+ T cell function in KRAS-mutant colorectal cancer
What is the main question of the paper?
How do KRAS mutations drive immune evasion in colorectal cancer by regulating TRIP6 phosphorylation, metabolic reprogramming, and the subsequent lactylation of extracellular proteins?
How did the anthor address the question?
■Step1
KRAS/ERK-Driven TRIP6 Phosphorylation and Metabolic Reprogramming Researchers found that TRIP6 is highly phosphorylated at Ser147 (p-TRIP6) in KRAS-mutant colorectal cancer, which correlates with reduced CD8+ T cell infiltration and poor patient prognosis. KRAS mutations constitutively activate ERK1/2 kinases, which directly phosphorylate TRIP6, explaining why this mechanism is specific to KRAS-mutant strains. In the wild-type condition, unphosphorylated TRIP6 binds to KDM1A in the nucleus, inhibiting its activity and suppressing ENO2 expression to limit glycolysis. In contrast, phosphorylated TRIP6 dissociates from KDM1A, allowing KDM1A to remove inhibitory marks from the ENO2 promoter. As a result, ENO2 is upregulated, significantly boosting glycolysis and leading to massive production and export of lactate into the extracellular microenvironment.
■Step2
Lactate-Induced CD44 Lactylation and T Cell Exhaustion The accumulated extracellular lactate, facilitated by the enzyme AARS1, induces lactylation of the CD44 receptor on T cells. This lactylation impairs CD44 binding to hyaluronan (HA) and disrupts AKT signaling, ultimately leading to T cell exhaustion and reduced anti-tumor immune activity.
■Step3
Therapeutic Targeting of TRIP6 Phosphorylation To counteract this mechanism, the researchers developed a peptide, mPT6, to block TRIP6 phosphorylation. Experimental results showed that combining mPT6 with Anti-PD-1 therapy reactivates the immune system and significantly inhibits KRAS-mutant tumor growth.
What is the strength of the paper?
This study provides a groundbreaking explanation of how KRAS-mutant tumors establish immune shields through metabolic remodeling, specifically by defining extracellular lactylation. Its greatest highlight lies in discovering a novel pathway where metabolites directly regulate the function of immune cell membrane proteins.
Comment
KRAS-mutant colorectal cancer is clinically known to be associated with limited treatment options and poor prognosis. In this context, I found this paper interesting because it shows that tumor-intrinsic changes can affect not only tumor growth itself, but also anti-tumor immunity through alterations in the surrounding metabolic environment. I felt that this concept, in which tumor-driven changes in the metabolic environment reshape immune responses, may be applicable beyond KRAS-mutant colorectal cancer, especially to conditions such as cancer cachexia, where host metabolism and immune function are closely linked.
Comment by Tomoaki Shirakawa
