This Article Full Text Full Text (PDF) Supplementary Data Correction (v68,p1609) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Zhao, X. Articles by Band, V. Search for Related Content PubMed PubMed Citation Articles by Zhao, X. Articles by Band, V.

Cyclooxygenase-2 Expression during Immortalization and Breast Cancer Progression

Divisions of ¹ Cancer Biology and ² Molecular Oncology, Department of Medicine, ³ Department of Pathology, and ⁴ Center for Outcome Research and Education, Evanston Northwestern Healthcare Research Institute and Feinberg School of Medicine; ⁵ Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois; and ⁶ Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts

Requests for reprints: Vimla Band, Department of Genetics, Cell Biology & Anatomy, University of Nebraska Medical Center, DRC 6th Floor, 985805 Nebraska Medical Center, Omaha, NE 68198-5805. Phone: 402-559-8565; Fax: 402-559-7328; E-mail: vband{at}unmc.edu.

Identification of molecular aberrations in premalignant human mammary epithelial cells (hMEC), the precursors for breast cancers, is a central goal in breast cancer biology. Recent studies implicated expression of cyclooxygenase 2 (COX-2) as a marker to identify precursor cells for breast cancer. In this study, we analyzed COX-2 expression in preselection and postselection hMEC cells and observed similar COX-2 levels in both cells. Interestingly, immortalization of postselection cells using various methods leads to a dramatic decrease in COX-2 expression. Similar to immortal cells, the majority of breast cancer cell lines expressed low levels of COX-2 protein. Finally, analyses of COX-2 expression in a series of specimens from reduction mammoplasty, adenosis, ductal carcinoma in situ, and infiltrating ductal carcinoma showed down-regulation of COX-2 expression during tumor progression. Importantly, down-regulation of COX-2 using small interfering RNA in cells showed no effect on cell proliferation, anchorage-independent growth, migration, or invasion. These results show that (a) COX-2 overexpression does not seem to predict a breast cancer precursor cell and does not provide advantage for the cell to be transformed; (b) inhibition of COX-2 does not affect hMEC growth and oncogenic behavior in the conditions analyzed; and (c) COX-2 expression is decreased in breast cancer cell lines and cancer specimens as compared with normal mammary epithelial cells. [Cancer Res 2008;68(2):467–75]

This article has been cited by other articles:

				Correction: COX-2 Expression Decreases in Breast Cancer Progression Cancer Res., March 1, 2008; 68(5): 1609 - 1609. [Full Text] [PDF]