intrinsic-factor and Carcinoma

Caco-2 cells grown on 0.45-micron filters, in Millicell chambers, form intact monolayers with many of the properties of polarized intestinal epithelial cells. It is reported here that these cells bind and internalize intrinsic factor-cobalamin complexes and that after 14-28 days in culture this specific binding is exclusively located on the apical membrane. Caco-2 cells also synthesize and secrete a protein with properties similar to transcobalamin II. This protein is secreted from the basolateral side of the cells after 20 days in culture. Specific apical-to-basolateral transcellular transport of [57Co]cobalamin also occurs between 20 and 28 days in culture. Thus, Caco-2 cells provide the first polarized human cell system for studying the transepithelial transport of cobalamin.

Topics: Biological Transport; Carcinoma; Cell Line, Transformed; Chromatography, Ion Exchange; Colon; Colonic Neoplasms; Electric Conductivity; Epithelium; Humans; Intrinsic Factor; Microscopy, Electron; Protein Binding; Time Factors; Tumor Cells, Cultured; Vitamin B 12

Topics: Alkaline Phosphatase; Bile; Blood Proteins; Carcinoma; Cerebrospinal Fluid Proteins; Chemistry, Clinical; Gastric Juice; Humans; Immunoglobulins; Intrinsic Factor; Isoelectric Focusing; Isoenzymes; Kidney Cortex; Kidney Medulla; Kidney Neoplasms; Methods; Multiple Sclerosis; Nephrotic Syndrome; Nerve Tissue Proteins; Proteinuria; Vitamin B 12

Topics: Animals; Ascites; Benzimidazoles; Carcinoma; Carcinoma, Ehrlich Tumor; Clostridium; Cobamides; Intrinsic Factor; Lactobacillus; Metabolism; Mice; Pharmacology; Research; Tissue Culture Techniques; Vitamin B 12