title: Cyclooxygenase-2 overexpression in MCF-10F human breast epithelial cells inhibits proliferation, apoptosis and differentiation, and causes partial transformation.
abstract: To investigate the effects of cyclooxygenase-2 (COX-2) overexpression on breast cancer development, we stably transfected MCF-10F human breast epithelial cells with an expression vector containing human COX-2 cDNA oriented in the sense (10F-S) or antisense (10F-AS) direction. As expected, 10F-S cells expressed elevated levels of COX-2 protein, whereas this protein was undetectable in the 10F-AS cells. Prostaglandin E(2) production in these cells reflected COX-2 levels. The 10F-S cells had a significantly decreased rate of proliferation compared to 10F-AS or parental cells, and a delay in progression through the G(1) phase of the cell cycle. COX-2 overexpression also caused resistance to detachment-induced apoptosis (anoikis) as well as an inhibition of differentiation in cells cultured in Matrigel. Furthermore, after approximately 20 passages in culture, 10F-S cells developed fibroblast-like features, expressed vimentin, and formed foci of dense growth when cultured at confluence, suggesting that the cells were undergoing epithelial to mesenchymal transition (EMT). The 10F-S cells, however, were unable to grow in soft agar or form tumors in nude mice, suggesting that they were only partially transformed. Our observations suggest that COX-2 overexpression in human breast epithelial cells will predispose the mammary gland to carcinogenesis.
authors.affiliation: Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Canada.
authors.forename: Suying
authors.initials: S
authors.lastname: Lu
authors.forename: Guo
authors.initials: G
authors.lastname: Yu
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Zhu
authors.forename: Michael C
authors.initials: MC
authors.lastname: Archer
mesh_terms: D023102:Anoikis; D017209:Apoptosis / Q000502:physiology*; D001940:Breast / Q000166:cytology* / Q000201:enzymology; D002448:Cell Adhesion; D002453:Cell Cycle; D002454:Cell Differentiation / Q000502:physiology*; D002455:Cell Division / Q000502:physiology*; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000201:enzymology*; D005260:Female; D005822:Genetic Vectors; D006801:Humans; D008565:Membrane Proteins; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection
chemical_list: D008565:Membrane Proteins; D011994:Recombinant Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone