대장암 미세환경에서 S100A8/A9 유도와 골수세포 분화에 대한 근섬유모세포의 역할

Dept. of Medicine/박사The overexpression of S100A8/A9 is associated with inflammatory and neoplastic conditions. S100A8/A9 proteins and myeloid cells in the tumor microenvironment play important roles in cancer invasion and progression. S100A8/A9 are involved in the metastatic processes and act as chemo-attractant to facilitate the homing of tumor cells to premetastatic niches. Most studies have focused on the interactions between tumor cells and inflammatory cells and between tumor cells and myofibroblasts in tumor microenvironments. The effect of tumor-infiltrated myofibroblasts on myeloid cells in the tumor microenvironment is relatively unknown. Therefore, the aim of this study was to investigate the role of myofibroblasts in the induction of S100A8/A9 as well as in the differentiation of myeloid cells in the colorectal cancer (CRC) microenvironment.To investigate the interactions among cancer cells, myofibroblasts, and inflammatory cells in CRC microenvironment, a series of 10 CRC cell lines, 18CO cells (colonic myofibroblasts) and THP-1 cells (inflammatory myeloid cells), which were co-cultured with each other or cultured in conditioned medium (CM) from other cells were used. Expression of S100A8/A9 was evaluated by Western blot, immunohistochemical staining and immunofluorescence. The secreted factors from the cell lines were analyzed using cytokine antibody array. Flow cytometry analysis was performed to analyze the differentiation markers of myeloid cells.CM from 18CO cells induced increased expression of S100A8/A9 in THP-1 cells. 18CO CM induced differentiation of THP-1 cells into myeloid-derived suppressor cells (CD33 and arginase-1) or M2 macrophages (CD163 and CD206) expressing S100A8/A9. IL-6 and IL-8 were increased in 18CO CM, compared to those in both controls and THP-1 CM. Neutralizing antibodies to IL-6 and IL-8 attenuated 18CO CM-induced increased expression of S100A8/A9. Increased expression of S100A8/A9 was noted in inflammatory cells along with myofibroblasts in human CRC tissues. S100A8 expressing cells exhibited CD68 expression and tumor-infiltrated myofibroblasts expressed IL-8 in human CRC tissues. In conclusion, it was demonstrated that the release of IL-6 and IL-8 from myofibroblasts induced the expression of S100A8/A9 in tumor-infiltrating myeloid cells, and myofibroblasts induced the differentiation of myeloid cells into myeloid-derived suppressor cells or M2 macrophages expressing S100A8/9 in vitro.prohibitio