Expression of chemotaxis- and angiogenesis-related factors in human monocytes following interaction with colon cancer cells is suppressed by low-dose lipopolysaccharide.

We have previously reported that mRNA expression of chemotaxis- and angiogenesis-related factors in human monocytes increased following interaction with colon cancer cells. Recently, it was also reported that mRNA expression of the chemotaxis-related factor, monocyte chemotactic protein (MCP)-1, in mouse macrophages following treatment with low-dose lipopolysaccharide (LPS) was significantly lower compared to that following treatment with high-dose LPS, and that low-dose LPS failed to activate the classical nuclear factor (NF)-κB pathway. In the present study, we examined changes in mRNA expression of chemotaxis- and angiogenesis-related factors in human monocytes following low-dose LPS treatment and subsequent interaction with colon cancer cells.The human monocyte cell line THP-1 was treated with LPS and subsequently co-cultured with the human colon cancer cell line DLD-1. mRNA expression was analyzed by quantitative real-time PCR.mRNA expression of MCP-1, vascular endothelial growth factor (VEGF)-A, tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-8 in THP-1 cells treated with low-dose LPS (100 pg/ml) decreased compared to untreated THP-1 cells after five days of co-culture with DLD-1 cells.mRNA expression of chemotaxis- and angiogenesis-related factors in human monocytes following interaction with colon cancer cells is suppressed by prior treatment with low-dose LPS. Thus, low-dose LPS treatment of human monocytes may be useful for prevention and therapy of colon cancer.