Epithelial properties of human colonic carcinoma cell line Caco-2: effect of secretagogues.
Human colonic carcinoma Caco-2 cells grown in vitro form epithelial layers of highly polarized cells. Unlike colonic adsorptive cells they possess a mucosal membrane with very limited ionic conductance, even after exposure to aldosterone. When grown on filters, Caco-2 cells were sensitive to various secretagogues; these included 10(-5) M dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP) and 10(-10) M vasoactive intestinal peptide, both of which, added serosally, enhanced the short-circuit current. The same applied to mucosal forskolin. Caco-2 cell sensitivity to serosal epinephrine was lower. Ion substitutions and 22Na-36Cl flux measurements indicated the possibility of secretagogue-dependent chloride secretion. Measurements on cells grown on Petri dishes and exposed to 1 mM DBcAMP for 1 h enabled detection of more profound modifications. Sustained 20-mV cell depolarization and a large reduction in the relative electrical resistance of the mucosal membrane were concomitant with a sizable decrease in 36Cl accumulation. These results suggest that Caco-2 cells, which to some extent resemble colonic crypt cells, possess the cAMP-dependent mucosal chloride conductance characteristic of secretory cells.
Grasset
E
E
Bernabeu
J
J
Pinto
M
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D003994:Bucladesine / Q000494:pharmacology*; D002460:Cell Line; D002712:Chlorides / Q000378:metabolism; D005576:Colforsin; D003110:Colonic Neoplasms / Q000648:ultrastructure*; D004224:Diterpenes / Q000494:pharmacology*; D004848:Epithelium / Q000648:ultrastructure*; D006801:Humans; D009092:Mucous Membrane / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*
D002712:Chlorides; D004224:Diterpenes; D005576:Colforsin; D014660:Vasoactive Intestinal Peptide; D003994:Bucladesine; D012964:Sodium