Targeting MondoA–TXNIP restores antitumour immunity in lactic-acid-induced immunosuppressive microenvironment

Abstract

In the tumour microenvironment, accumulated lactic acid (LA) promotes tumour immune evasion by facilitating regulatory T cell (Treg) immunosuppressive function and restraining CD8+ T cell cytotoxicity, but the underlying mechanism remains elusive. Here we report that transcriptional factor MondoA-induced thioredoxin interacting protein (TXNIP) transcription is a common feature of both Treg and CD8+ T cells in response to lactic acid. In contrast to reduction in immunosuppressive capacity in MondoA-deficient Treg cells, loss of MondoA enhanced CD8+ T cell cytotoxic function in the lactic-acid-induced immunosuppressive microenvironment, by restoring glucose uptake and glycolysis. Mechanistically, lactic acid relied on sentrin/SUMO-specific protease 1 (SENP1) to stimulate the MondoA–TXNIP axis, which impaired TCR/CD28-signal-induced CD8+ T cell activation. Importantly, targeting the MondoA–TXNIP axis potentiated antitumour immunity in multiple cancer types and synergized with anti-PD-1 therapy to promote effective T cell responses in colorectal cancer. Our results demonstrate that the MondoA–TXNIP axis is a promising therapeutic target for improving cancer immunotherapy. Xu et al. identify the MondoA–TXNIP signalling axis as a regulator of antitumour immune surveillance in response to lactic acid in the tumour microenvironment.