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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.

Original publication

DOI

10.1038/sj.bjc.6603593

Type

Journal article

Journal

Br j cancer

Publication Date

26/02/2007

Volume

96

Pages

575 - 582

Keywords

Animals, Apoptosis, Breast Neoplasms, Celecoxib, Cell Cycle, Cell Line, Tumor, Cell Proliferation, Cyclooxygenase 2, Cyclooxygenase 2 Inhibitors, Female, Humans, Immunohistochemistry, Lymphangiogenesis, Membrane Proteins, Mice, Mice, Inbred BALB C, Mice, Nude, Proto-Oncogene Proteins c-akt, Pyrazoles, Structure-Activity Relationship, Sulfonamides, Xenograft Model Antitumor Assays