title: Cyclooxygenase-2 inhibition: effects on tumour growth, cell cycling and lymphangiogenesis in a xenograft model of breast cancer.
abstract: Cyclooxygenase-2 (COX-2) is associated with poor-prognosis breast cancer. We used a nude mouse xenograft model to determine the effects of COX-2 inhibition in breast cancer. Oestrogen receptor (ER)-positive MCF7/HER2-18 and ER-negative MDAMB231 breast cancer cell lines were injected into nude mice and allowed to form tumours. Mice then received either chow containing Celecoxib (a COX-2 inhibitor) or control and tumour growth measured. Tumour proliferation, apoptosis, COX-2, lymphangiogenesis and angiogenesis were assessed by immunohistochemistry (IHC), Western blotting or Q-PCR. Celecoxib inhibited median tumour growth in MCF7/HER2-18 (58.7%, P=0.029) and MDAMB231 (46.3%, P=0.0002) cell lines compared to control. Cyclooxygenase-2 expression decreased following Celecoxib treatment (MCF7/HER2-18 median control 65.3% vs treated 22.5%, P=0.0001). Celecoxib increased apoptosis in MCF7/HER2-18 tumours (TUNEL 0.52% control vs 0.73% treated, P=0.0004) via inactivation of AKT (median pAKT(ser473) 57.3% control vs 35.5% treated, P=0.0001--confirmed at Western blotting). Q-PCR demonstrated decreased podoplanin RNA (lymphangiogenesis marker) in the MCF7/HER2-18 - median 2.9 copies treated vs 66.6 control (P=0.05) and MDAMB231-treated groups--median 160.7 copies vs 0.05 control copies (P=0.015), confirmed at IHC. Cyclooxygenase-2 is associated with high levels of activated AKT(ser473) and lymphangiogenesis in breast cancer. Cyclooxygenase-2 inhibition decreases tumour growth, and may potentially decrease recurrence, by inactivating AKT and decreasing lymphangiogenesis.
authors.affiliation: Department of Academic Surgery, South Manchester University Hospital, Research and Education Building 2nd Floor, Southmoor Road, Wythenshawe, Manchester M23 9LT, UK.
authors.forename: N L P
authors.initials: NL
authors.lastname: Barnes
authors.forename: F
authors.initials: F
authors.lastname: Warnberg
authors.forename: G
authors.initials: G
authors.lastname: Farnie
authors.forename: D
authors.initials: D
authors.lastname: White
authors.forename: W
authors.initials: W
authors.lastname: Jiang
authors.forename: E
authors.initials: E
authors.lastname: Anderson
authors.forename: N J
authors.initials: NJ
authors.lastname: Bundred
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D000068579:Celecoxib; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D051546:Cyclooxygenase 2 / Q000096:biosynthesis / Q000187:drug effects*; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D042583:Lymphangiogenesis / Q000187:drug effects*; D008565:Membrane Proteins / Q000096:biosynthesis / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D051057:Proto-Oncogene Proteins c-akt / Q000187:drug effects / Q000378:metabolism; D011720:Pyrazoles / Q000494:pharmacology* / Q000627:therapeutic use; D013329:Structure-Activity Relationship; D013449:Sulfonamides / Q000494:pharmacology* / Q000627:therapeutic use; D023041:Xenograft Model Antitumor Assays
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D008565:Membrane Proteins; D011720:Pyrazoles; D013449:Sulfonamides; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D051057:Proto-Oncogene Proteins c-akt; D000068579:Celecoxib