Endotoxin Triggers Tumor Initiation Events in Nontumorigenic Breast Epithelial Cells and Enhances Invasion-Related Phenotype in Pretumorigenic and Tumorigenic Breast Epithelial Cells

Figure 2

Short-term endotoxin treatment upregulates levels of inflammatory mediators produced by MDA-MB-231 human breast cancer cells. (a) Gelatin zymography of conditioned media collected from untreated control (0 µg/ml) and ET-treated cells (0.1 and 1 µg/ml) upon reaching 75% confluence after treatment showed upregulation of MMP-9 activity in MDA-MB-231 cells. No differences in the growth profile of ET-treated cells were noted, and all cultures reached 75–80% confluence within the same time frame. (b) Quantification of fold increase in peak area of MMP-9 bands shown in the previous zymogram. Each bar represents triplicate analyses of mean ± SD. The abundant unregulated MMP-2 levels noted in the conditioned media are also noted in growth medium (GM). (c) Upregulation of NO and (d) IL 1-β levels in MDA-MB-231 conditioned media collected from ET-treated cells (0.1 and 1 µg/ml) compared to untreated controls (0 µg/ml), upon reaching 75% confluence after treatment. Each bar represents triplicate analyses of mean ± SD. compared to the untreated control.

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