However, the involvement of COX-2 in the angiogenic response of tumor cells and the role of COX-2 in up-regulating

VEGF release by NSCLC cells has been unclear. In order to elucidate the relationship between COX-2 and tumor-associated VEGF expression, we first investigated the association of COX-2 expression in NSCLC tissue samples with clinical and pathologic factors, BIX 1294 cell line including VEGF expression and MVD. Our findings indicated a significant difference in VEGF staining and MVD between NSCLC specimens with strong and weak COX-2 expression. When all of the predictors were included in a multivariate analysis, COX-2 expression retained its significant association with VEGF staining and MVD, demonstrating that COX-2 expression is an independent predictive click here factor for changes in both VEGF expression and MVD in NSCLC tissue. These

results suggest that COX-2 may contribute to maintaining a high level of VEGF in NSCLC tissue, thereby Mocetinostat mouse playing an important role in tumor-induced angiogenesis. Previous reports provide no insight into how up-regulating COX-2 might mediate tumor-associated VEGF expression in NSCLC tissue in a physiological context. In order to address this question, we assessed changes in tumor-associated VEGF expression in NSCLC cells that accompany changes in COX-2 by treating cells directly with COX-2 protein. Because this is the first such study, there was no available information on the concentrations of COX-2 that are effective in stimulating proliferation in NSCLC cells in vitro. Accordingly, we used an MTT assay to investigate the characteristic tumor cell responses to COX-2 as a chemical agent in three NSCLC cell lines. Crucially, our data demonstrated

that A549, H460, and A431 tumor cells were stimulated to proliferate by exogenously Farnesyltransferase applied COX-2, whereas normal bronchial epithelial cells (HBE) used as a control were not. The EC50 values for COX-2 in stimulating proliferation were not substantially different among the tested tumor cell lines. Based on our data, it is reasonable to propose that COX-2 is an active agent in these tested NSCLC cells. We also found using flow cytometry that COX-2 exposure up-regulated tumor-associated VEGF expression in NSCLC cells, exhibiting prominent dose-dependent activity. This phenomenon was particularly evident in A549 lung adenocarcinoma cells. Thus, tumor-associated expression of VEGF may be promoted by COX-2 in NSCLCs. Although COX-2-mediated VEGF up-regulation in NSCLC has been well studied by several groups [26, 27], the detailed molecular mechanism underlying this process had not been previously demonstrated. To explore the linkage between COX-2 and tumor-associated VEGF expression, we employed inhibitors of protein kinase signaling pathways.