Proinflammatory Proteins S100A8/S100A9 Activate NK Cells via Interaction with RAGE.

S100A8/A9, a proinflammatory protein, is upregulated in inflammatory diseases, and also has a tumor-promoting activity by the recruitment of myeloid cells and tumor cell invasion. However, whether the expression of S100A8/A9 in tumors predicts a good or poor prognosis is controversial in the clinical setting. In this study, to clarify the in vivo role of S100A8/A9 in the tumor microenvironment, we s.c. inoculated Pan02 cells stably expressing S100A8 and S100A9 proteins (Pan02-S100A8/A9) in syngeneic C57BL/6 mice. Unexpectedly, after small tumor nodules were once established, they rapidly disappeared. Flow cytometry showed that the number of NK cells in the tumors was increased, and an administration of anti-asialoGM1 Ab for NK cell depletion promoted the growth of Pan02-S100A8/A9 s.c. tumors. Although the S100A8/A9 proteins alone did not change the IFN-γ expression of NK cells in vitro, a coculture with Pan02 cells, which express Rae-1, induced IFN-γ production, and Pan02-S100A8/A9 cells further increased the number of IFN-γ(+) NK cells, suggesting that S100A8/A9 enhanced the NK group 2D ligand-mediated intracellular activation pathway in NK cells. We then examined whether NK cell activation by S100A8/A9 was via their binding to receptor of advanced glycation end product (RAGE) by using the inhibitors. RAGE antagonistic peptide and anti-RAGE Ab inhibited the IFN-γ production of NK cells induced by S100A8/A9 proteins, and an administration of FPS-ZM1, a RAGE inhibitor, significantly enhanced the in vivo growth of Pan02-S100A8/A9 tumors. We thus found a novel activation mechanism of NK cells via S100A8/A9-RAGE signaling, which may open a novel perspective on the in vivo interaction between inflammation and innate immunity.

Narumi K ，Miyakawa R ，Ueda R ，Hashimoto H ，Yamamoto Y ，Yoshida T ，Aoki K ... -  《-》

S100a8/a9 released by CD11b+Gr1+ neutrophils activates cardiac fibroblasts to initiate angiotensin II-Induced cardiac inflammation and injury.

Wu Y ，Li Y ，Zhang C ，A X ，Wang Y ，Cui W ，Li H ，Du J ... -  《-》

RAGE-dependent regulation of calcium-binding proteins S100A8 and S100A9 in human THP-1.

Proinflammatory cell activation via the receptor for advanced glycation end products (RAGE) pathway may play a central pathogenetic role in atherosclerosis. Since S100A8/A9 was recently identified as ligand of RAGE, we determined the effects of proinflammatory cytokines on RAGE-mediated induction of gene expression of S100A8 and S100A9. mRNA levels of S100A8 and S100A9 were upregulated following cytokine stimulation with IL-6 (1, 10, 100 ng/ml) or TNFα (10 ng/ml) in human THP-1 cells. Preincubation of cells with 2000 ng/ml AGE (advanced glycation end products) before cytokine stimulation resulted in upregulation of RAGE. Pretreatment of THP-1 with AGE followed by stimulation with IL-6 (10 ng/ml) or TNFα (10 ng/ml) further increased S100A8 and S100A9 mRNA expression and S100A8/A9 release into cell culture supernatant, as compared to pretreatment with non-glycated albumin as control. Binding of AGE to RAGE was blocked with a neutralizing anti-RAGE antibody. Normal mouse IgG served as control. Cytokine-stimulated induction of S100A8 and S100A9 mRNA levels as well as of S100A8/A9 release after preincubation of cells with AGE were significantly suppressed by RAGE blockade, indicating a RAGE-dependent pathway of AGE-mediated S100A8/A9 expression.The cytokine-induced potentiated S100A8 and S100A9 expression under conditions with a high AGE burden is able to aggravate proinflammatory conditions via activation of the RAGE pathway.

Eggers K ，Sikora K ，Lorenz M ，Taubert T ，Moobed M ，Baumann G ，Stangl K ，Stangl V ... -  《-》

S100A8/A9 aggravates post-ischemic heart failure through activation of RAGE-dependent NF-κB signaling.

Volz HC ，Laohachewin D ，Seidel C ，Lasitschka F ，Keilbach K ，Wienbrandt AR ，Andrassy J ，Bierhaus A ，Kaya Z ，Katus HA ，Andrassy M ... -  《-》

The role of myofibroblasts in upregulation of S100A8 and S100A9 and the differentiation of myeloid cells in the colorectal cancer microenvironment.

S100A8/A9 and myeloid cells in the tumor microenvironment play an important role in cancer invasion and progression, and the effect of tumor-infiltrated myofibroblasts on myeloid cells in the tumor microenvironment is relatively unknown. Accordingly, we investigated the role of myofibroblasts in the upregulation 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 the microenvironment of CRC, we used 10 CRC cell lines, 18CO cells and THP-1 cells, which were co-cultured with each other or cultured in conditioned media (CM) of other cells. Expression of S100A8/A9 was evaluated via 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. 18CO CM induced increased expression of S100A8/A9 in THP-1 cells. Increased expression of S100A8/A9 was noted in inflammatory cells of the peri- and intra-tumoral areas, along with myofibroblasts in colon cancer tissue. S100A8/A9-expressing inflammatory cells also exhibited CD68 expression in colon cancer tissue, and 18CO CM induced differentiation of THP-1 cells into myeloid-derived suppressor cells (MDSCs) or M2 macrophages expressing S100A8/A9. Significant amounts of IL-6 and IL-8 were detected in 18CO CM, compared to those in both controls and THP-1 CM, and tumor-infiltrated myofibroblasts expressed IL-8 in colon cancer tissue. Finally, neutralizing antibodies to IL-6 and IL-8 attenuated 18CO CM-induced increased expression of S100A8/A9. The upregulation of S100A8/A9 in tumor-infiltrated myeloid cells could be triggered by IL-6 and IL-8 released from myofibroblasts, and myofibroblasts might induce the differentiation of myeloid cells into S100A8/9-expressing MDSCs or M2 macrophages in the CRC microenvironment.

Kim JH ，Oh SH ，Kim EJ ，Park SJ ，Hong SP ，Cheon JH ，Kim TI ，Kim WH ... -  《-》