Tumor cells are the source of osteopontin and bone sialoprotein expression in human breast cancer

Sharp, J. A., Sung, V., Slavin, J., Thompson, E.W., & Henderson, M.A. (1999) Tumor cells are the source of osteopontin and bone sialoprotein expression in human breast cancer. Laboratory Investigation, 79(7), pp. 869-877.

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Bone sialoprotein (BSP) and osteopontin (OPN) are secreted glycoproteins with a conserved Arg-Gly-Asp (RGD) integrin-binding motif and are expressed predominantly in bone. The RGD tripeptide is commonly present in extracellular attachment proteins and has been shown to mediate the attachment of osteosarcoma cells and osteoclasts. To determine the origin and incidence of BSP and OPN mRNA expression in primary tumor, a cohort of archival, primary invasive breast carcinoma specimens was analyzed. BSP transcripts were detected in 65% and OPN transcripts in 77% of breast cancers examined. In general, BSP and OPN transcripts were detected in both invasive and in situ carcinoma components. The transcripts were not detected in surrounding stromal cells or in peritumoral macrophages. Despite its abundance in carcinomas, BSP expression was not detected in a panel of 11 human breast cancer cell lines (MCF-7, T47D, SK-Br-3, MDA-MB-453, MDA-MB- 231, MDA-MB-436, BT549, MCF-7(AOR), Hs578T, MDA-MB-435, and LCC15-MB) and OPN expression was detected only in two of these (MDA-MB-435 and LCC15-MB). To examine the possibility that expression of these genes was down-regulated in cell culture, several cell lines were grown as nude mouse xenografts in vivo; however, these tumors also failed to express BSP. OPN expression was identified in all cell lines grown as nude mouse xenografts. Our data suggest that in human primary breast tumors, the origin of BSP and OPN mRNA is predominantly the breast cancer cells and that expression of these transcripts is influenced by the tumor environment.

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49 citations in Scopus
45 citations in Web of Science®
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ID Code: 72711
Item Type: Journal Article
Refereed: Yes
Additional Information: Cited By (since 1996):45
Export Date: 6 May 2014
Source: Scopus
PubMed ID: 10418827
Additional URLs:
ISSN: 1530-0307
Divisions: Current > QUT Faculties and Divisions > Faculty of Health
Deposited On: 11 Jun 2014 03:07
Last Modified: 11 Jun 2014 03:07

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