The objective of this study was to determine the effect of macrophages on growth of human colon cancer cells. The results showed that co-culture of colon cancer cells with macrophages inhibited the growth of colon cancer cells (HCT116 and SW620) depending on the number of macrophages, RAW 264.7 cells, and activated THP-1 cells accompanied by down regulation of pSTAT3 in cancer cells. We also found that expression and release of cancer cell growth inhibitory cytokines, IL-1 receptor antagonist (IL-1ra) and IL-10, was increased in macrophages. Blocking of the STAT3 pathway with specific inhibitor and siRNA of STAT3 abolished the growth of colon cancer cells and expression of IL-1ra and IL-10. In addition, neutralization of IL-1ra and IL-10 with antibodies resulted in reversal of macrophage-induced inhibition of cancer cell growth. These data showed that IL-1ra and IL-10 released from macrophages inhibit growth of colon cancer cells through inhibition of the STAT3 pathway.

• Jin Tae Hong(College of Pharmacy and Medical Research Center, Chungbuk National University) Corresponding author
• Dohee Won(College of Pharmacy and Medical Research Center, Chungbuk National University)
• Mi Hee Park(College of Pharmacy and Medical Research Center, Chungbuk National University)
• Sun Mi Kown(College of Pharmacy and Medical Research Center, Chungbuk National University)
• Miran Jo(College of Pharmacy and Medical Research Center, Chungbuk National University)
• Sang-Yoon Nam(College of Veterinary Medicine, Chungbuk National University)
• Beom Jun Le(College of Veterinary Medicine, Chungbuk National University)
• Young Won Yun(College of Veterinary Medicine, Chungbuk National University)
• Ki-Wan Oh(College of Pharmacy and Medical Research Center, Chungbuk National University)
• Sang Bae Han(College of Pharmacy and Medical Research Center, Chungbuk National University)