The Combination of Phytic Acid and Inositol Alleviates Metastasis of Colorectal Cancer in Mice by Inhibiting PI3K/AKT Pathway and M2 Macrophage Polarization

Abstract

This study established an orthotopic mouse model of colorectal cancer (CRC) liver metastasis to investigate the inhibitory effects of combined phytic acid (IP6) and inositol (INS) at different ratios on CRC liver metastasis, as well as their impact on the phosphatidylinositol 3-kinase/serine/threonine protein kinase (PI3K/AKT) signaling pathway and macrophage polarization. Combined treatment with varying ratios of IP6 and INS significantly enhanced survival rates and reduced both cecal tumor weight and the incidence of liver metastasis. Flow cytometry indicated an increased CD4⁺/CD8⁺ T cell ratio and a decrease in regulatory T cells, with the 1 : 3 group showing the most pronounced effects (p < 0.05). Cytokine levels were modulated after treatment with varying IP6-to-INS ratios, with a significant reduction in CCL20, interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) (p < 0.05), and an increase in IL-10 and transforming growth factor-β (TGF-β) (p < 0.05). Western blot analysis confirmed a significant downregulation of PI3K/AKT pathway proteins, including PI3K, phosphorylated (p)-PI3K, AKT, p-AKT, and mammalian target of rapamycin (p < 0.05), with the 1 : 3 group exhibiting the greatest effect. Additionally, the expression of M2 macrophage polarization-related proteins CD163 and CD206 was downregulated (p < 0.05). Our findings suggest that the combination of IP6 and INS alleviates CRC metastasis by downregulating the PI3K/AKT pathway and influencing macrophage polarization, with the most significant inhibitory effect observed at an IP6-to-INS ratio of 1 : 3.