Metabolites as signalling molecules in the tumour immune microenvironment

Alterations in key metabolic pathways are required for tumour development and the adaptation of tumour cells to intrinsic or extrinsic stresses, as well as for the regulation of immune cell fate and immune responses in the tumour microenvironment. In particular, the dysregulation or alteration of certain metabolites produced by tumour cells has been shown to be important in creating the immunosuppressive tumour microenvironment. Recent studies have broadened our understanding of the interactions between metabolites and antitumour immunity. Here we highlight how, beyond their metabolic role, metabolites can function as signalling molecules to modulate the behaviours of immune cells and tumour cells. We also discuss potential therapeutic strategies targeting specific metabolites and future research directions in metabolite sensing.