cox 2 role in bone metastases via IL8--role for cox inhibitors

[Lani]

A large number of her2+ breast cancers are cox 2 positive (will try to see if I can find the stats again)--don't think I ever saw discussion of whether ER- or ER+ her2neu. Here they discuss cox2 having a role via IL8 in ER- but they are looking at cell line MCF7 which is her2- negative :

1: J Surg Res. 2006 May 5; [Epub ahead of print] Links

Involvement of IL-8 in COX-2-Mediated Bone Metastases from Breast Cancer.

Singh B, Berry JA, Vincent LE, Lucci A.

Department of Surgical Oncology, University of Texas M.D. Anderson Cancer Center, Houston, Texas.

BACKGROUND: Cyclooxygenase-2 (COX-2) overexpression by a primary tumor correlates with poor prognosis in breast cancer, including early spread to bone. Interleukin-8 (IL-8) stimulates osteoclastogenesis and resorption of bone, and elevated IL-8 levels predict early metastatic spread of breast cancer. The purpose of this study was to test our hypothesis that tumors that overexpress COX-2 induce IL-8 production. MATERIALS AND METHODS: We cotransfected MCF-10A (nonmalignant breast epithelial) cells, as well as MDA-231 (highly metastatic human breast cancer) cell lines with a pSG5-COX-2 vector and pEF1a-Luc-IRES-Neo vector (luciferase reporter). COX-2 overexpression was confirmed by Western blot and PGE(2) (a product of the COX-2 pathway) immunoassay. IL-8 production was measured by immunoassay. In vivo testing used a nude mouse model to measure COX-2 and IL-8 production from breast cancer cells that had metastasized to bone (bone-seeking clones (BSCs)). Long bone metastases were localized and quantified by luciferase imaging (Xenogen IVIS system) and X-ray. BSCs were isolated and cultured and then tested for the production of PGE(2) and IL-8. RESULTS: COX-2 overexpression caused a 4- to 5-fold increase in IL-8 production in both MCF-10A and MDA-231 cells in vitro. In vivo, we observed that the MDA-231-BSC (metastatic cells isolated from bone metastases) produced significantly greater levels of both PGE(2) and IL-8 compared to the parental MDA-231 cells (P < 0.01). In contrast to the results obtained with these estrogen receptor-negative cell lines, COX-2 expression failed to induce IL-8 in the MCF-7 estrogen receptor-positive breast cancer cell line. Treatment with the COX-2 inhibitor NS-398 at a low 1-mu[scap]M dose reduced the production of IL-8 in COX-2-transfected MDA-231 cells by 30%, thus confirming the involvement of COX-2 in IL-8 induction. CONCLUSION: COX-2 expression induced formation of PGE(2) and IL-8 in breast cancer cells. Since PGE(2) and IL-8 stimulate osteoclasts to resorb bone, COX-2 inhibition is a potential target for treatment to prevent bone metastases.

PMID: 16678856 [PubMed - as supplied by publisher]