Fig. 6
From: The roles of tissue resident macrophages in health and cancer
Intestinal resident macrophages facilitate tumor cell invasion. The transcription factor C-MYC regulates the expression of pro-tumoral genes, such as VEGF, HIF-1α and TGF-β in Tumor-associated macrophages (TAMs), which are characterized by the expression of pattern recognition receptors CD163 and MP, as well as the secretion of cytokines IL-10 and TGF-β, as well as chemokines including CCL17, CCL22 and CCL24. Tumor cells produce lactic acid through the mediation of HIF-1α, which induces VEGF and arginase-1 expression in intestinal resident macrophages. Cancer cells secrete IL-34, promoting the polarization of monocyte towards M2 macrophages, thereby further enhancing tumor proliferation and metastasis. TAMs enhance tumor migration and invasion by the ERK signaling pathway, secreting IL-6, and this effect is mediated via the JAK2/STAT3/FoxQ1 axis