Fig. 4

COX-2 expression by tumor and immune cells correlates with PGE2 secretion. A, In human tumor cells, cytokines significantly induce COX-2 but not COX-1 expression across cancer types. 19 tumor lines from 6 cancer types were cultured with the indicated cytokines for 1 day. COX proteins were detected by Western blotting. Band intensities were quantified and normalized as described in Methods. Means ± SD are indicated. Wilcoxon signed-rank test, 2-sided comparisons to no cytokine, *p = 0.030, **p = 0.005, ***p = 0.001. Similar results were observed with intracellular flow cytometry (not shown). B, Cytokine induction of COX-2 in human monocytes. Peripheral blood monocytes from a normal donor were exposed to the indicated cytokines in vitro for 1 day. COX-2 expression was assessed by intracellular FACS. Data representative of 2 experiments with monocytes from 3 normal donors. C, COX-2 expression by tumor cells and monocytes correlates with PGE2 secretion. 537mel, JHU-022 and monocytes were treated with the indicated cytokines for 1 day. COX-2 expression was quantified by intracellular FACS and PGE2 secretion was measured by ELISA. Pearson correlation, 2-sided p-value