The Role and Treatment Strategies of Ammonia-Related Metabolism in Tumor Microenvironment

Tumor cells achieve their adaptability through various metabolic reprogramming processes. Among them, ammonia, as a traditional metabolic waste, plays an increasingly important role in the tumor microenvironment along with its associated metabolites. Other cells in the microenvironment can also reshape the immune status of the microenvironment by regulating ammonia- related metabolism, and targeting this metabolic aspect has emerged as a potential strategy for tumor treatment. In this study, we have systematically reviewed the source and destination of ammonia in tumor cells, as well as the links between ammonia and other biological processes. We have also analyzed the ammonia-related metabolic regulation of other cells (including T cells, macrophages, dendritic cells, natural killer cells, myeloid-derived suppressor cells, and stromal cells) in the tumor microenvironment, and summarized the tumor treatment methods that target this metabolism. Through ammonia-related metabolic reprogramming, tumor cells obtain the energy they need for rapid growth and proliferation. Multiple immune cells and stromal cells in the microenvironment also interact with each other through this metabolic regulation, ultimately leading to immune suppression. Despite the heterogeneity of tumors and the complexity of cellular functions, further research into therapeutic interventions targeting ammonia-related metabolism is warranted. This review has focused on the role and regulation of ammonia-related metabolism in tumor cells and other cells in the microenvironment, and highlighted the efficacy and prospects of targeted ammonia- related metabolism therapy.