期刊名称:Proceedings of the National Academy of Sciences
印刷版ISSN:0027-8424
电子版ISSN:1091-6490
出版年度:2003
卷号:100
期号:5
页码:2736-2741
DOI:10.1073/pnas.0435410100
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要:Up-regulation of cyclooxygenase-2 (COX-2) and overproduction of prostaglandins have been implicated in the initiation and/or progression of colon cancer. However, it is uncertain in which cells and how COX-2 is induced initially in the tumor microenvironment. We found that a conditioned medium of the colon cancer cell line, LS 180, contained a factor to induce COX-2 in human peripheral blood mononuclear cells. This factor was purified biochemically and revealed to be mucins. A small amount of mucins ({approx}100 ng of protein per ml) could elevate prostaglandin E2 production by monocytes. The mucins induced COX-2 mRNA and protein levels of monocytes in a dose- and time-dependent manner, indicating a COX-2-mediated pathway. We also have examined immunohistochemically the localization of COX-2 protein and mucins in human colorectal cancer tissues. It is noteworthy that COX-2-expressing macrophages were located around the region in which mucins were detectable, suggesting that COX-2 also was induced by mucins in vivo. These results suggest that mucins produced by colon cancer cells play a critical role in the initial induction of COX-2 in the tumor microenvironment.