Tumor metabolite lactate promotes tumorigenesis by modulating MOESIN lactylation and enhancing TGF-? signaling in regulatory T cells

Regulatory T (Treg) cells play a vital role in maintaining the immunosuppressive tumor microenvironment. Lactate is a crucial metabolite in cancer and is related to tumor prognosis, metastasis, and overall survival. In this study, we focus on the effects of lactate on Treg cells. In vitro, lactate improves Treg cell stability and function, whereas lactate degradation reduces Treg cell induction, increases antitumor immunity, and decreases tumor growth in mice. Mechanistically, lactate modulates Treg cell generation through lactylation of Lys72 in MOESIN, which improves MOESIN interaction with transforming growth factor (3 (TGF-(3) receptor I and downstream SMAD3 signaling. Cotreatment with anti-PD-1 and a lactate dehydrogenase inhibitor has a stronger antitumor effect than anti-PD-1 alone. Individuals with hepatocellular carcinoma who responded to anti-PD-1 treatment have lower levels of MOESIN lactylation in Treg cells than nonresponding individuals. Thus, we identify lactate as an essential small molecule that reinforces Treg cells in the tumor microenvironment through lactylation.

Automated summary

The lactate in tumor microenvironment plays a crucial role in regulating Treg cells. It can improve Treg cell stability and function, while its degradation reduces Treg cell induction. Lactate modulates Treg cell generation through lactylation of MOESIN, leading to enhanced interaction with TGF-β receptor I and downstream SMAD3 signaling. Combining lactate dehydrogenase inhibitor with anti-PD-1 treatment shows stronger antitumor effects. MOESIN lactylation levels in Treg cells are associated with the response to anti-PD-1 treatment in hepatocellular carcinoma patients.