Granulocyte-macrophage colony-stimulating factor protects mice against hepatocellular carcinoma by ameliorating intestinal dysbiosis and attenuating inflammation

BACKGROUND: Hepatocellular carcinoma (HCC) is the third leading cause of cancer mortality worldwide. The gut microbiota can help maintain healthy metabolism and immunity. Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a critical factor in promoting health and homeostasis; it promotes intestinal immunity, stimulates bone marrow precursors to generate macrophage colonies, and enhances the antibacterial and antitumor activity of circulating monocytes. As such, GM-CSF may protect against HCC development by regulating immunity as well as intestinal microecology. AIM: To investigate the impact of GM-CSF on the gut microbiome and metabolic characteristics of HCC. METHODS: Thirty-six male BALB/c nude mice were divided into three groups: Control (n = 10), HCC (n = 13), and HCC + GM-CSF (GM-CSF overexpression, n = 13). We utilized HCC cells to establish orthotopic transplantation tumor models of HCC with normal and over-expressing GM-CSF. Liver injury, immune inflammatory function and intestinal barrier function were evaluated. The fecal microbiome and metabolome were studied using 16S rRNA absolute quantification sequencing and gas chromatography-mass spectrometry. RESULTS: GM-CSF overexpression significantly affected the gut microbiome of mice with HCC and resulted in a high abundance of organisms of the genera Roseburia, Blautia and Butyricimonass, along with a significant reduction in Prevotella, Parabacteroides, Anaerotruncus, Streptococcus, Clostridium, and Mucispirillum. Likewise, GM-CSF overexpression resulted in a substantial increase in fecal biotin and oleic acid levels, along with a prominent decrease in the fecal succinic acid, adenosine, fumaric acid, lipoic acid, and maleic acid levels. Correlation analysis revealed that the intestinal microbiota and fecal metabolites induced by GM-CSF were primarily involved in pathways related to reducing the inflammatory response, biotin metabolism, and intestinal barrier dysfunction. CONCLUSION: GM-CSF can protect against HCC development by regulating immunity and modulating the abundance of specific intestinal microorganisms and their metabolites. This study provides new insights into the therapeutic approaches for HCC.