G-CSF promotes the development of hepatocellular carcinoma by activating the PI3K/AKT/mTOR pathway in TAM.

ABSTRACT

OBJECTIVE: This investigation seeks to elucidate the role of the Granulocyte Colony-Stimulating Factor (G-CSF) in the progression of hepatocellular carcinoma (HCC), as well as the impact of the substance on related signaling pathways within the disease matrix. METHODS: Nude mouse tumor-bearing assay was used to detect tumor progression. Levels of Mannose/CD68 and CD34/Mannose within these samples and the concentrations of Mannose and inducible Nitric Oxide Synthase (iNOS) in macrophages were quantified using immunofluorescence techniques. The angiogenic capability was assessed via tube formation assays, and protein expressions of G-CSF, Vascular Endothelial Growth Factor (VEGF), Transforming Growth Factor-beta (TGF-ß), Matrix Metalloproteinases 2 and 9 (MMP2/9), SH2-containing protein tyrosine phosphatase-2 (SHP-2), phosphorylated PI3K/total PI3K (P-PI3K/t-PI3K), phosphorylated AKT/total AKT (P-AKT/t-AKT), and phosphorylated mTOR/total mTOR (P-mTOR/t-mTOR) were measured through Western Blot analysis in both tumor tissues and macrophages. RESULTS: Administration of G-CSF resulted in a marked augmentation of tumor volume. Macrophage Mannose expression was significantly elevated upon G-CSF treatment, while iNOS levels were conspicuously diminished. G-CSF substantially enhanced the secretion of VEGF, TGF-ß, and MMPs in tumor tissues. Macrophage parameters, following incubation in G-CSF pre-treated conditioned medium, indicated enhanced tube-forming capabilities relative to the control, an effect mitigated by the introduction of specific inhibitors. Furthermore, the G-CSF group exhibited a notable reduction in SHP-2 expression, alongside a substantial elevation in the phosphorylation levels of the PI3K/AKT/mTOR pathway proteins across all tumor-bearing paradigms. CONCLUSION: G-CSF ostensibly facilitates the advancement of hepatocellular carcinoma by activating the PI3K/AKT/mTOR signaling cascade within Tumor-Associated Macrophages (TAM).