Background
Recent research shows that tumor-associated macrophages (TAMs) are the primary consumers of glucose in tumor tissue, surpassing that of tumor cells. Our previous studies revealed that inhibiting glucose uptake impairs the survival and tumor-promoting function of hypoxic TAMs, suggesting that glucose reduction by energy restriction (calorie restriction or short-term fasting) may has a significant impact on TAMs. The
Conclusions
These results support further clinical combination studies of FMD and anti-angiogenic therapy as potential anti-tumor strategies.
Methods
The effect of FMD on TAMs and its synergistic effects with apatinib were observed using an orthotopic mouse breast cancer model. An in vitro cell model, utilizing M2 macrophages derived from THP-1 cell line, was intended to assess the effects of low glucose on TAMs under hypoxic and normoxic conditions. Bioinformatics was used to screen for potential mechanisms of action, which were then validated both in vivo and in vitro.
Results
FMD significantly inhibit the pro-tumor function of TAMs in vivo and in vitro, with the inhibitory effect being more pronounced under hypoxic conditions. Additionally, the combination of FMD-mediated TAMs inhibition with apatinib results in synergistic anti-tumor activity. This effect is partially mediated by the downregulation of CCL8 expression and secretion by the mTOR-HIF-1α signaling pathway. Conclusions: These results support further clinical combination studies of FMD and anti-angiogenic therapy as potential anti-tumor strategies.