B7-H3 (CD276) is an immune checkpoint from the B7 family of molecules and is abnormally expressed in tumor cells as a co-inhibitory molecule to promote tumor progression. Within the tumor microenvironment (TME), B7-H3 promotes tumor progression by impairing the T cell response, driving the polarization of tumor-associated macrophages (TAMs) to M2 phenotype, and inhibiting the function of other immune cells. In addition, B7-H3 promotes tumor cell proliferation, migration, invasion, metabolism disorder, angiogenesis, and resistance to treatment to promote tumor progression through its non-immunological functions. Immunotherapy targeting B7-H3, as well as combinations with other immune checkpoint therapies, have shown certain efficacy. In this review, we synthesizes the expression of B7-H3 and its mechanism to promote tumor progression through inducing immunomodulation and non-immunological functions, as well as its role of B7-H3 in tumor therapy, aiming to provide a reference for the clinical treatment of tumors.

The relationship between metabolism and cancer is a major focus of current research, with an increasing number of studies highlighting the significant role of various metabolites in tumor cells, such as lactate, acetic acid, lysine, serine, tryptophan, palmitic acid, succinate, etc. These metabolites are involved in numerous biological processes within tumor cells, including transcription, translation, post-translational modification (PTM) of proteins, cell cycle regulation, and metabolism, thereby modulating tumor proliferation, migration, and drug resistance. Metabolite-mediated PTMs of proteins undoubtedly play a vital role in tumor cells, affecting both histones and non-histone proteins, covering modifications such as lactylation, crotonylation, acetylation, palmitoylation, and succinylation. Therefore, this review aims to elaborate on the abnormal levels of some major metabolites, related metabolic pathways, and the latest protein acyl PTMs they mediate in tumor cells, providing new insights for diagnosis and therapy in the field of oncology.

PD-1 restrains effective killing of cancer cells by the immune system and is predominantly located on the surface of T cells or other immune cells. However, cancer cells also express PD-1 to varying degrees, which is commonly associated with a poor prognosis. Here, we investigated the regulation and function of PD-1 expression in prostate cancer (PCa) and revealed the impact on the tumor microenvironment. PD-1 expression in cancer cells positively correlated with Gleason grade and metastasis but negatively correlated with CD8+ T cell infiltration in PCa patients. PCa cells secreted PD-1 in exosomes that enhanced the activity of myeloid-derived suppressor cells (MDSCs) by activating JAK/STAT3 signaling. The activated MDSCs in turn reduced the infiltration of CD8+ T cells within the tumor, promoting tumor immune evasion. The ubiquitin-specific protease USP7 induced deubiquitination and elevated the abundance of PD-1 in PCa, and USP7 inhibition sensitized PCa tumors to anti-PD-1 antibody treatment. Given the modest efficacy of current immunotherapeutic approaches for PCa, strategies to inhibit the secretion of PD-1-bearing exosomes or USP7 function may emerge as promising immunostimulatory interventions for treating PCa.

Background: Only a few bladder cancer patients benefit from anti‐programmed cell death protein 1/programmed cell death ligand 1 immunotherapy. The cluster of differentiation 47 (CD47) plays an important role in tumor immune evasion. CD47 is a highly glycosylated protein, however, the mechanisms governing CD47 glycosylation and its potential role in immunosuppression are unclear. Therefore, this study aimed to evaluate the function of CD47 glycosylation in bladder cancer. Methods: Western blotting, immunohistochemistry, and flow cytometry were used to measure protein expression, protein‐protein interactions, and phagocytosis in bladder cancer. A murine model was employed to investigate the impact of mannosidase alpha class 1B member 1 (MAN1B1) modification of CD47 on anti‐phagocytosis in vivo. An ex vivo model, patient‐derived tumor‐like cell clusters, was used to examine the effect of targeting MAN1B1 on phagocytosis. Results: Our research identified that aberrant CD47 glycosylation was responsible for its immunosuppression. The glycosyltransferase MAN1B1 responsible for CD47 glycosylation was highly expressed in bladder cancer. Abnormal activation of extracellular signal‐regulated kinase (ERK) was significantly associated with MAN1B1 stability by regulating the interaction between MAN1B1 and the E3 ubiquitin ligase HMG‐CoA reductase degradation 1 (HRD1). Mechanistically, abnormally activated ERK stabilized MAN1B1, resulting in the glycosylation of CD47 and facilitating immune evasion by enhancing its interaction with signal‐regulatory protein alpha (SIRP‐α). In vitro and in vivo experiments demonstrated that MAN1B1 knockout weakened CD47‐mediated anti‐phagocytosis. MAN1B1 inhibitors promoted phagocytosis without causing anemia, offering a safe alternative to anti‐CD47 therapy. Conclusions: This comprehensive analysis uncovered that ERK activation stabilizes MAN1B1 by regulating the interaction between MAN1B1 and HRD1, facilitates immune evasion via CD47 glycosylation, and presents new potential targets and strategies for cancer immunotherapy that do not cause anemia.

Natural killer (NK) cells are innate cytotoxic lymphocytes capable of eliminating malignant cells independent of prior antigen sensitization, thereby constituting a critical first-line defense in tumor immunosurveillance. Within the tumor microenvironment (TME), metabolic dysregulation profoundly impairs NK cell effector function, and accumulating studies have investigated the regulatory effects of extracellular metabolites on NK cells. This review systematically delineates the direct mechanistic interplay between extracellular metabolites and NK cell antitumor immunity, with particular emphasis on their roles as structural components, bioenergetic substrates, metabolic reprogramming inducers, modification donors, gene transcription regulators, stress response mediators, intracellular pH modulators, and ligands engaging cognate receptors to initiate downstream signaling cascades. Furthermore, we discuss the therapeutic strategies targeting metabolites to potentiate NK cell functionality, encompassing modulation of metabolite availability within the TME and exploitation of metabolite-sensitive signaling axes. In addition, combination of metabolic interventions with other modalities, such as adoptive NK cell transfer and anti-programmed cell death protein 1/programmed death-ligand 1 therapy, is also evaluated for prospective applications. This review provides a conceptual framework for understanding the metabolic regulation of NK cells, highlighting emerging directions for advancing NK-cell-centered cancer immunotherapy through metabolic modulation.