Targeting HGF/c-MET signaling to regulate the tumor microenvironment: Implications for counteracting tumor immune evasion

Tumor-Associated Macrophages: Polarization, Immunoregulation, and Immunotherapy

Tumor-associated macrophages' (TAMs) origin, polarization, and dynamic interaction in the tumor microenvironment (TME) influence cancer development. They are essential for homeostasis, monitoring, and immune protection. Cells from bone marrow or embryonic progenitors dynamically polarize into pro- or anti-tumor M2 or M1 phenotypes based on cytokines and metabolic signals. Recent advances in TAM heterogeneity, polarization, characterization, immunological responses, and therapy are described here. The manuscript details TAM functions and their role in resistance to PD-1/PD-L1 blockade. Similarly, TAM-targeted approaches, such as CSF-1R inhibition or PI3Kγ-driven reprogramming, are discussed to address anti-tumor immunity suppression. Furthermore, innovative biomarkers and combination therapy may enhance TAM-centric cancer therapies. It also stresses the relevance of this distinct immune cell in human health and disease, which could impact future research and therapies.

HGF Aggravated Periodontitis-Associated Gut Barrier and Microbial Dysfunction: Implications for Oral-Gut Axis Regulation

While periodontitis is increasingly linked to systemic disorders through the oral-gut axis, the molecular mediators driving gut microbiota dysbiosis and barrier disruption remain elusive. Hepatocyte growth factor (HGF), a novel regulator of inflammatory bone loss in periodontitis, may serve as a critical communicator between oral infection and distal intestinal pathology. This study investigates how HGF overexpression modulates the gut microbial ecosystem and intestinal barrier integrity in a transgenic periodontitis model. In this study, we combined 16S rRNA sequencing of fecal microbiota with comprehensive gut barrier assessments, including systemic markers (D-lactate, LPS, and DAO ELISA), structural integrity (villous morphology), and molecular analysis (ZO-1, occludin, and NOD2 immunohistochemistry), using HGF-overexpressing transgenic (HGF-Tg) mice with periodontitis. The results demonstrated that HGF increased gut permeability in the context of periodontitis, as evidenced by elevated serum levels of D-lactate and LPS compared to wild type (WT) mice. In addition, gut villous morphology disorder was observed in HGF-Tg mice with periodontitis. HGF also diminished the protein level of occludin and upregulated NOD2 expression in mice with periodontitis. Moreover, HGF-Tg mice with periodontitis exhibited significant dysbiosis of gut microbiota, with reduced levels of probiotics (e.g., Faecalibaculum). Notably, HGF also increased the enrichment of the periodontitis-associated pathogens (e.g., Desulfovibrio and Streptococcus) in the gut. Microbial functions, particularly metabolic pathways, were significantly altered by HGF when periodontitis occurred. Some microorganisms like g_Desulfovibrio may play a role in gut barrier disorder in HGF-Tg mice with periodontitis. Overall, our findings position HGF as a novel orchestrator of oral-gut crosstalk, where its overexpression reshapes gut microbial ecology toward a "leaky gut" phenotype to compromise intestinal barrier integrity, further deepening our understanding of the oral-gut axis.