Loss of intercellular adhesion precedes metastatic behavior in carcinomas. NCAM is an important intercellular adhesion molecule that is absent in aggressive colon carcinomas (Gastroenterology 108:A529, 1995). The purpose of the present study was to prove that NCAM is capable of mediating colon cancer intercellular cell adhesion. Methods: Eight colon cancer cell lines obtained from the ATCC were screened by immunohistochemistry and RT-PCR for the presence on NCAM cell surface protein or mRNA expression respectively. Cells were grown in graded doses of anti-NCAM monoclonal antibody (Zymed), with an IgG control or in media alone. A blinded observer counted the number of cell clumps and total number of cells. Data are reported as the percent of cells growing in clumps. Results: One of the 8 cell lines tested expressed mRNA as well as NCAM protein as determined by RT-PCR and immunohistochemistry. Cells lacking NCAM demonstrated little clumping with 4.3 ± .6 % (SEM) of cells in clumps. The cell line with NCAM had significantly greater clumping 21.6 ± .8 % of cells (p<.05, t-test). The figure on the left demonstrates the effect of anti-NCAM on colon cancer cell clumping in this cell line. The x-axis represents log-order anti-NCAM dilutions from 1:10̂6 on the left to 1:1 on the for right. The y-axis is the percent of cells found in clumps. Control cultures are represented by the open boxes and those grown in the presence of serial dilutions of anti-NCAM antibody are shown with closed boxes. There was a dose-dependent reduction in cell clumping with increasing concentrations of anti-NCAM antibody (p<.05, ANOVA with contrasts). Conclusions: NCAM expression occurs in some colon cancer cell lines and results in a tendency for the cells to clump together. The clumping behavior was reversed by anti-NCAM antibody in the media. These data suggest that NCAM mediates cell-cell adhesion in colon cancer and supports our hypothesis that loss of this molecule enables cells to break away and metastasize.
|Original language||English (US)|
|Journal||Journal of Investigative Medicine|
|State||Published - Jan 1 1996|
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)