Role of macrophage PKM2 in inflammation and tumor progression and its targeted therapy

Macrophages play a dual role of promoting or inhibiting in inflammation and tumor progression, highly dependent on the dynamic changes of M1/M2 polarization. In inflammation, M1/M2 polarization balance determines the outbreak of inflammation or tissue repair. In the tumor microenvironment, M1 tumor-associated macrophages (TAMs) exert both anti-tumor and pro-tumor effects, while M2 TAMs promote tumor progression. PKM2 regulates the M1/M2 polarization and cytokine secretion of macrophages through the pyruvate kinase activity of tetramers as well as the protein kinase activity and transcriptional co-activator function of dimers. This review summarizes the role and molecular mechanism of macrophage PKM2 in inflammation and tumor progression, highlighting its potential as a therapeutic target in inflammatory diseases and cancers. Macrophage PKM2 plays a promoting role in inflammation and tumor progression due to its dual regulatory characteristics of metabolism and immunity. It can not only meet the energy demands of macrophages through glycolytic metabolism, but also affect the immune response through enzyme activity-dependent and non-dependent mechanisms. The non-enzyme activity-dependent mechanism by which PKM2 regulates immune responses serves as a bridge connecting cellular metabolism and immune responses. The unresolved issues include the functional heterogeneity of macrophage PKM2 across different macrophage subtypes, its specific roles in lipid and amino acid metabolism, its contribution to tumor microenvironmental metabolic reprogramming, and PKM2-mediated interactions of macrophages with other cells.