H green and red fluorescence respectively). The nucleus was stained byH green and red fluorescence

H green and red fluorescence respectively). The nucleus was stained by
H green and red fluorescence respectively). The nucleus was stained by DAPI. S100A8/A9 heterodimers were detectable using the dimer-specific antibody 27E10 from BMA Biomedicals prelabeled with green fluorescence. The co-localization of S100A9 and S100A8 or S100A8/A9 was showed in merged pictures (D, I, N, S, X) and larger merged pictures (E, J, O, T, Y). White arrow in 3 T shows co-localization of S100A9 and S100A8/A9 in chronic gastritis. Bar length, 50 m.Fan et al. BMC Cancer 2012, 12:316 http://www.biomedcentral.com/1471-2407/12/Page 9 ofFigure 4 Effect of S100A9 recombinant protein on invasion and migration of buy Q-VD-OPh gastric cancer cell lines. In transwell assay, AGS (A) and BGC-823 (C) cells were treated with serum-free medium or medium containing 10, 20, 50 or 100 ng/ml S100A9 recombinant protein. Invasive cells were counted in randomly nine selected microscopic fields (200?. In wound healing assay, AGS (B) and BGC-823 (D) cells were treated with serum-free RPMI-1640 medium or medium containing 100 ng/ml S100A9 recombinant protein. Photos were captured by an inverted phase-contrast microscope at 0 h, 24 h and 48 h after wounding. Three independent experiments were performed. Results were presented as means ?S.D. of these independent experiments. P value vs. control group.S100A9, a member of S100 family, is abundant in granulocytes, monocytes and activated keratinocytes during various inflammatory conditions. In this study, we found that S100A9 was specifically located in inflammatory cells infiltrating gastric cancer tissues and chronic gastritis tissues, while all gastric cancer cells or adjacent cells of gastric mucosa did not express S100A9. Our results agree with previous studies demonstrating high expression of S100A9 in infiltrating immune cells in various cancer types including colorectal cancer [21] and pancreatic cancer [29]. At the same time, in other cancer types, such as lung cancer [16], prostate cancer [17], and breast cancer [19,30], S100A9 is expressed mainly by neoplastic tumor cells themselves. It has been suggested that tumor cells of glandular origin can express S100A9 when they are poor differentiated [18] or under pathological stress conditions [31-33]. However, we did not find any S100A9-positive gastric cancer cell including poorly differentiated ones. High expression of S100A9 in the inflammatory cells in gastric cancer tissues may indicate that S100A9 plays an important role in gastric cancer development.Correlation among S100A9 expression, clinicopathological features and patient prognosis varies in different cancer types. In lung cancer [16] and invasive ductal carcinoma of the breast [19], overexpression of S100A9 in cancer cells has been shown to contribute to the development and progression of cancer. In thyroid carcinoma [34], expression of S100A8 and S100A9 in cancer cells is crucial for dedifferentiation. In bladder tumors, overexpression of S100A4, S100A8 or S100A11, but not S100A9 in cancer tissues is associated with stage progression, invasion, metastasis and poor survival [35]. So far studies of S100A protein expression in inflammatory cells infiltrating cancer have been rare due to lack of appropriate way to quantify the S100A expression by inflammatory cells. Only two studies evaluated S100A9 expression in a cancer-associated environment [21,29]. The results in colorectal cancer showed PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/26740125 that high S100A9 cell count was not associated with patient survival but instead positively correlated with tumor.