title: Cyclooxygenase-2 up-regulates CCR7 via EP2/EP4 receptor signaling pathways to enhance lymphatic invasion of breast cancer cells.
abstract: Recent studies demonstrate that cyclooxygenase-2 (COX-2) expression is frequently associated with lymph node metastasis. However, the mechanism by which COX-2 increases the invasion of cancer cells to lymph node is unclear. CCR7 is a chemokine receptor that plays important roles in the mediation of migration of leukocytes and dendritic cells toward lymphatic endothelial cells (LECs) that express receptor ligand CCL21. We found that treatment of prostaglandin E(2) or ectopic expression of COX-2 in MCF-7 cells up-regulated CCR7 expression. On the contrary, knockdown of COX-2 by small hairpin RNA reduced CCR7 in COX-2-overexpressing MDA-MB-231 cells. Interaction of CCR7 and CCL21 was important for the migration of breast cancer cells toward LECs because antibodies against these two molecules inhibited the migration. We also found that COX-2 increased CCR7 expression via the EP2 and EP4 receptor in breast cancer cells. EP2 and EP4 agonists stimulated CCR7 in MCF-7 cells, whereas antagonists or small hairpin RNA of EP2 and EP4 attenuated CCR7 in MDA-MB-231 cells. Protein kinase A and AKT kinase were involved in COX-2-induced CCR7. Pathological analysis demonstrated that COX-2 overexpression was associated with CCR7, EP2, and EP4 expressions in breast tumor tissues. In addition, CCR7 expression in COX-2-overexpressing tumors was significantly correlated with lymph node metastasis. Collectively, we suggest that CCR7 is a down-stream target for COX-2 to enhance the migration of breast cancer cells toward LECs and to promote lymphatic invasion.
authors.affiliation: Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
authors.forename: Mei-Ren
authors.initials: MR
authors.lastname: Pan
authors.forename: Ming-Feng
authors.initials: MF
authors.lastname: Hou
authors.forename: Hui-Chiu
authors.initials: HC
authors.lastname: Chang
authors.forename: Wen-Chun
authors.initials: WC
authors.lastname: Hung
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology*; D045744:Cell Line, Tumor; D054421:Chemokine CCL21 / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D015232:Dinoprostone / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008954:Models, Biological; D009361:Neoplasm Invasiveness; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D054400:Receptors, CCR7 / Q000378:metabolism*; D018078:Receptors, Prostaglandin E / Q000378:metabolism*; D058307:Receptors, Prostaglandin E, EP2 Subtype; D058309:Receptors, Prostaglandin E, EP4 Subtype; D015398:Signal Transduction; D015854:Up-Regulation
chemical_list: C515478:CCL21 protein, human; C515370:CCR7 protein, human; D054421:Chemokine CCL21; C545644:PTGER2 protein, human; C545650:PTGER4 protein, human; D054400:Receptors, CCR7; D018078:Receptors, Prostaglandin E; D058307:Receptors, Prostaglandin E, EP2 Subtype; D058309:Receptors, Prostaglandin E, EP4 Subtype; D051546:Cyclooxygenase 2; D051057:Proto-Oncogene Proteins c-akt; D015232:Dinoprostone