Oxamate enhances the efficacy of CAR-T therapy against glioblastoma via suppressing ectonucleotidases and CCR8 lactylation

Abstract

Background Chimeric antigen receptor (CAR)-T immunotherapy fails to treat solid tumors due in part to immunosuppressive microenvironment. Excess lactate produced by tumor glycolysis increases CAR-T immunosuppression. The mechanism of lactate inducing the formation of immunosuppressive microenvironment remains to be further explored. Methods Immunocyte subpopulations and molecular characteristics were analyzed in the orthotopic xenografts of nude mice using flow cytometry assay and immunohistochemical staining after oxamate, a lactate dehydrogenase A (LDHA) inhibitor, and control T or CAR-T cells injection alone or in combination. RT-qPCR, western blot, flow cytometry, immunofluorescence, luciferase reporter assay, chromatin immunoprecipitation and ELISA were performed to measure the effect of lactate on the regulation of CD39, CD73 and CCR8 in cultured glioma stem cells, CD4 + T cells or macrophages. Results Oxamate promoted immune activation of tumor-infiltrating CAR-T cells through altering the phenotypes of immune molecules and increasing regulatory T (Treg) cells infiltration in a glioblastoma mouse model. Lactate accumulation within cells upregulated CD39, CD73 and CCR8 expressions in both lactate-treated cells and glioma stem cells-co-cultured CD4 + T cells and macrophages, and intracellular lactate directly elevated the activities of these gene promotors through histone H3K18 lactylation. Conclusions Utilizing lactate generation inhibitor not only reprogramed glucose metabolism of cancer stem cells, but also alleviated immunosuppression of tumor microenvironment and reduced tumor-infiltrating CAR-Treg cells, which may be a potential strategy to enhance CAR-T function in glioblastoma therapy.

A review of lactate-lactylation in malignancy: its potential in immunotherapy

“…Another strategy focuses on developing targeted drugs that affect lactate-lactylation to interfere with its effects on tumors and immune cells. Currently, notable progress has been achieved in studies targeting MCT4 ( 43 , 44 ) and LDH ( 45 , 49 ), but inhibitors targeting glycolysis are still at the preclinical stage involving animal model experiments without sufficient clinical translation. Despite the potential of targeting Lactate-Lactylation, there exist several challenges and limitations that hinder its clinical translation.…”

“…Numerous researchers have attempted to investigate the impact of lactate-lactylation targeted strategies on the efficacy of tumor vaccines. Sun et al conducted a study exploring combined treatment with an LDH-A inhibitor and CAR-T therapy in a mouse model of glioblastoma multiforme (GBM) (49). Their findings demonstrated that LDH-A inhibitor Oxamate effectively reduced CAR-Treg cell levels and adenosine production within the TME by decreasing histone H3K18 lactylation levels.…”

Histone lactylation: from tumor lactate metabolism to epigenetic regulation

“…Lactate can promote the expression of CD39 and CD73 in a variety of cells in the tumor microenvironment, which are the main characteristics of the inhibitory TME. Finally, this leads to the exhaustion of CD8 + T cells and an increase in Treg cells 117 .…”

The role of lactate-induced protein lactylation in gliomas: implications for preclinical research and the development of new treatments

“…Histone lactylation caused by the Warburg effect stimulates the expression of the NF-κB-related gene LINC01127 in gliomas, which in turn promotes the MAP4K4/JNK/NF-κB axis and glioblastoma cell self-renewal ( Li et al, 2023 ). Furthermore, studies have shown that oxamate suppresses the lactylation of C-C motif receptor 8 (CCR8), a hallmark of Treg cells that infiltrate tumors, hence increasing the effectiveness of CAR-T-cell therapy for patients with glioblastomas ( Sun et al, 2023 ).…”