Cyclooxygenase-2 uses the protein kinase C/ interleukin-8/urokinase-type plasminogen activator pathway to increase the invasiveness of breast cancer cells

International audienceCyclooxygenase-2 (COX-2) increases breast cancer cell invasion. Expression of various pro-angiogenic and pro-invasive factors has been correlated with high expression of COX-2. However, whether these factors are essential to COX-2-mediated breast cancer invasion, and the mechanisms by which COX-2 increases the expression of these factors are unknown. Our microarray results indicate that higher COX-2 expression was associated with increased levels of interleukin-8 (IL-8), a key factor in breast cancer invasion and metastasis. COX-2 overexpressing cells (MCF-7/COX-2), generated by transfecting COX-2-encoding plasmids into the poorly invasive MCF-7 breast cancer cells, were more invasive and produced higher IL-8 levels than the parental cells. To investigate the role of IL-8 in COX-2-mediated invasion, MCF-7 parental cells were incubated with IL-8. Exogenous IL-8 increased the invasiveness of MCF-7 cells. IL-8 is one pathway by which COX-2 mediates breast cancer invasion. Protein kinase A (PKA) and protein kinase C (PKC) are activated by COX-2 and are involved in IL-8 regulation. Inhibition of PKC, not PKA, decreased IL-8 production and invasion in MCF-7/COX-2 cells. Activation of PKC, not PKA, increased IL-8 production and invasion in MCF-7 cells. Thus, the invasive effects of COX-2 are mediated by PKC, not PKA. Activity of the urokinase-type plasminogen activator (uPA) was increased in MCF-7 cells by COX-2 overexpression or by the addition of a PKC activator or by IL-8. Inhibition of PKC decreased uPA activity in MCF-7/COX-2 cells. Furthermore, inhibition of uPA activity decreased the invasiveness of MCF-7/COX-2 cells, indicating that uPA was essential to COX-2-mediated invasion. Herein we demonstrate for the first time a detailed mechanism by which COX-2 increases breast cancer invasion: the PKC/IL-8/uPA pathway

Cyclooxygenase-2 uses the protein kinase C/ interleukin-8/urokinase-type plasminogen activator pathway to increase the invasiveness of breast cancer cells

International audienceCyclooxygenase-2 (COX-2) increases breast cancer cell invasion. Expression of various pro-angiogenic and pro-invasive factors has been correlated with high expression of COX-2. However, whether these factors are essential to COX-2-mediated breast cancer invasion, and the mechanisms by which COX-2 increases the expression of these factors are unknown. Our microarray results indicate that higher COX-2 expression was associated with increased levels of interleukin-8 (IL-8), a key factor in breast cancer invasion and metastasis. COX-2 overexpressing cells (MCF-7/COX-2), generated by transfecting COX-2-encoding plasmids into the poorly invasive MCF-7 breast cancer cells, were more invasive and produced higher IL-8 levels than the parental cells. To investigate the role of IL-8 in COX-2-mediated invasion, MCF-7 parental cells were incubated with IL-8. Exogenous IL-8 increased the invasiveness of MCF-7 cells. IL-8 is one pathway by which COX-2 mediates breast cancer invasion. Protein kinase A (PKA) and protein kinase C (PKC) are activated by COX-2 and are involved in IL-8 regulation. Inhibition of PKC, not PKA, decreased IL-8 production and invasion in MCF-7/COX-2 cells. Activation of PKC, not PKA, increased IL-8 production and invasion in MCF-7 cells. Thus, the invasive effects of COX-2 are mediated by PKC, not PKA. Activity of the urokinase-type plasminogen activator (uPA) was increased in MCF-7 cells by COX-2 overexpression or by the addition of a PKC activator or by IL-8. Inhibition of PKC decreased uPA activity in MCF-7/COX-2 cells. Furthermore, inhibition of uPA activity decreased the invasiveness of MCF-7/COX-2 cells, indicating that uPA was essential to COX-2-mediated invasion. Herein we demonstrate for the first time a detailed mechanism by which COX-2 increases breast cancer invasion: the PKC/IL-8/uPA pathway

Expression of glutathione S-transferase π and α isoforms in breast cancer cell lines

Expression of glutathione S-transferase (GST)-π and GST-α isoforms in breast cancer cell lines. Protein lysates were obtained from exponentially growing MDA-MB-231, F10, and MCF-7/COX-2 cells. Western blot analyses using polyclonal GST-π and GST-α antibodies were performed. β-actin was used as a loading control.<p><b>Copyright information:</b></p><p>Taken from "TIMP-2 mediates the anti-invasive effects of the nitric oxide-releasing prodrug JS-K in breast cancer cells"</p><p>http://breast-cancer-research.com/content/10/3/R44</p><p>Breast Cancer Research : BCR 2008;10(3):R44-R44.</p><p>Published online 12 May 2008</p><p>PMCID:PMC2481491.</p><p></p

JS-K, but not JS-43-126, increases nitric oxide production in breast cancer cells

Conditioned medium supernatant was collected from MDA-MB-231, F10, and MCF-7/COX-2 cells treated in the absence or presence of JS-K or JS-43-126 for 72 hours. Total nitric oxide (NO) was determined by quantifying nitrite, the stable end product of NO oxidation, spectrophotometrically using a colorimetric nonenzymatic nitric oxide assay kit. Nitrite values were normalized for total cell counts and expressed as picomoles per 10cells. Columns indicate the mean of triplicate wells ± standard deviation. *Significant increase in NO levels relative to untreated cells, < 0.05.<p><b>Copyright information:</b></p><p>Taken from "TIMP-2 mediates the anti-invasive effects of the nitric oxide-releasing prodrug JS-K in breast cancer cells"</p><p>http://breast-cancer-research.com/content/10/3/R44</p><p>Breast Cancer Research : BCR 2008;10(3):R44-R44.</p><p>Published online 12 May 2008</p><p>PMCID:PMC2481491.</p><p></p

JS-K, but not JS-43-126, decreases the invasiveness of breast cancer cells across Matrigel

MDA-MB-231, F10, and MCF-7/COX-2 cells were added into Matrigel-coated transwell inserts and incubated with JS-K or JS-43-126 for 72 hours. Cells that invaded through the pores onto the lower side of the filter were fixed, stained, and photographed. The number of invaded cells for each filter was counted in five fields. The invasiveness of the cells is expressed as the mean number of cells that invaded to the lower side of the filter. Columns indicate the mean of triplicate wells ± standard deviation. *Significant decrease in the number of invaded cells relative to untreated cells, < 0.05. MDA-MB-231, F10, and MCF-7/COX-2 cells were plated on Matrigel-coated wells and incubated with JS-K. After 72 hours, cell proliferation was determined by Celltiter 96AQnonradioactive cell proliferation assay. Columns indicate the mean of pentaplicate wells ± standard deviation. MDA-MB-231 and F10 cells were added into type I collagen-coated transwell inserts and incubated with JS-K for 72 hours. Cells that invaded through the pores onto the lower side of the filter were fixed, stained, and photographed.<p><b>Copyright information:</b></p><p>Taken from "TIMP-2 mediates the anti-invasive effects of the nitric oxide-releasing prodrug JS-K in breast cancer cells"</p><p>http://breast-cancer-research.com/content/10/3/R44</p><p>Breast Cancer Research : BCR 2008;10(3):R44-R44.</p><p>Published online 12 May 2008</p><p>PMCID:PMC2481491.</p><p></p