Novel surface expression of reticulocalbin 1 on bone endothelial cells and human prostate cancer cells is regulated by TNF-α

• Published in: Journal of cellular biochemistry Vol. 104; no. 6; pp. 2298 - 2309
• Main Authors: Cooper, Carlton R., Graves, Bianca, Pruitt, Freddie, Chaib, Hassan, Lynch, Jill E., Cox, Andrew Koemeter, Sequeria, Linda, van Golen, Kenneth L., Evans, Angelo, Czymmek, Kirk, Bullard, Rebecca S., Donald, Carlton D., Sol-Church, Katia, Gendernalik, James D., Weksler, Babette, Farach-Carson, Mary C., Macoska, Jill A., Sikes, Robert A., Pienta, Kenneth J.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 15.08.2008
• Subjects: Blotting, Western; Bone and Bones - cytology; bone metastasis; Calcium-Binding Proteins - genetics; Calcium-Binding Proteins - metabolism; Cell Line; Cell Membrane - drug effects; Cell Membrane - metabolism; endothelial cells; Endothelial Cells - drug effects; Endothelial Cells - metabolism; Flow Cytometry; Gene Expression Regulation - drug effects; Humans; LNCaP; Male; Microscopy, Confocal; neoplasm; Peptide Library; phage display; progression; prostate; Prostatic Neoplasms - pathology; reticulocalbin 1; RNA, Messenger - genetics; RNA, Messenger - metabolism; Tumor Necrosis Factor-alpha - pharmacology
• ISSN: 0730-2312; 1097-4644
• DOI: 10.1002/jcb.21785

An unbiased cDNA expression phage library derived from bone‐marrow endothelial cells was used to identify novel surface adhesion molecules that might participate in metastasis. Herein we report that reticulocalbin 1 (RCN1) is a cell surface‐associated protein on both endothelial (EC) and prostate cancer (PCa) cell lines. RCN1 is an H/KDEL protein with six EF‐hand, calcium‐binding motifs, found in the endoplasmic reticulum. Our data indicate that RCN1 also is expressed on the cell surface of several endothelial cell lines, including human dermal microvascular endothelial cells (HDMVECs), bone marrow endothelial cells (BMEC), and transformed human bone marrow endothelial cells (TrHBMEC). While RCN1 protein levels were highest in lysates from HDMVEC, this difference was not statistically significant compared BMEC and TrHBMEC. Given preferential adhesion of PCa to bone‐marrow EC, these data suggest that RCN1 is unlikely to account for the preferential metastasis of PCa to bone. In addition, there was not a statistically significant difference in total RCN1 protein expression among the PCa cell lines. RCN1 also was expressed on the surface of several PCa cell lines, including those of the LNCaP human PCa progression model and the highly metastatic PC‐3 cell line. Interestingly, RCN1 expression on the cell surface was upregulated by tumor necrosis factor alpha treatment of bone‐marrow endothelial cells. Taken together, we show cell surface localization of RCN1 that has not been described previously for either PCa or BMEC and that the surface expression on BMEC is regulated by pro‐inflammatory TNF‐α. J. Cell. Biochem. 104: 2298–2309, 2008. © 2008 Wiley‐Liss, Inc.