Release of Carcinoembryonic Antigen from Human Tumor Cells by Phosphatidylinositol-Specific Phospholipase C: Highly Effective Extraction and Upregulation from LS-174T Colonic Adenocarcinoma Cells

摘要: Carcinoembryonic antigen (CEA), produced by gastrointestinal tumor cells, is anchored to cell membrane a glycosyl-phosphatidylinositol moiety which can be cleaved with phosphatidylinositol-specific phospholipase C (PI-PLC). We studied the extraction of CEA from living human colon carcinoma (LS-174T, HT-29, COLO-205, and HRT-18) pancreatic (CAPAN) cells PI-PLC Bacillus cereus. The total content LS-174T quantitated Triton X-1 14 followed radioimmunoassay or immunohistochemistry, was 3.5-fold higher than that other (P < 0.001). spontaneous release into culture medium also 0.00 1), reaching 620 ng/107 (≈28% cellular content) after 24 h. Overall, were highly susceptible PI-PLC, dependent on dose treatment time, leading in optimal conditions solubilization 4100 h (≈75% CEA). After at highest dose, lines remained viable growing, expression not exhausted but only reduced as compared untreated cells. At same amount solubilized P1-PLC exceeded reduction membranes, suggesting enzyme increased turnover. This particularly true for LS- 174T maintained 54% whereas extracted reached 190% this expression. Growing thus constitute an effective material producing high quantities cleavage, especially since these probably "regenerate" cause enhanced turnover during action, allowing continuous production. These experimental provide interesting model studying modulation release.