Activated macrophages induce metastatic behavior of colon cancer cells

Tumor-associated macrophages were linked to the growth, angiogenesis, and metastasis of variety of cancers. However, the role of macrophages in colon cancer is elusive. In the present study, we demonstrate that activated macrophage-conditioned medium (AMCM), containing tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6, markedly induced proliferation and migration of human colon cancer cells HCT116. Furthermore, AMCM significantly increased activation of transcription factor NF-κB and secretion of vascular endothelial growth factor (VEGF) from colon cancer cells, which subsequently induced capillary morphogenesis of human aortic endothelial cells. In conclusion, the interruption of signaling between activated macrophages and colon cancer cells could be considered as a new therapeutic strategy.