Pectin and pectic-oligosaccharides induce apoptosis in in vitro human colonic adenocarcinoma cells.
BACKGROUND
Dietary fibres have been associated with decreased risk of various cancers, although the mechanisms are unclear. Induction of apoptosis in tumour cells is thought to be an important protective mechanism against colorectal cancer. This work investigates the effects of pectins and pectic-oligosaccharides (POS) on the human colonic adenocarcinoma cell line HT29.


METHODS
The anti-proliferative effects of pectin and POS were studied by testing the HT29 cells for cytotoxicity, differentiation and/or apoptosis by lactate dehydrogenase, alkaline phosphatase and caspase-3 activity assays. DNA agarose gel electrophoresis was also carried out.


RESULTS
A significant reduction in attached cell numbers was observed after three days incubation. This decrease was neither due to cells undergoing necrosis nor differentiation. Increased apoptosis frequency, after incubation with 1% (w/v) pectin and/or POS, was demonstrated by caspase-3 activity and DNA laddering on agarose gel electrophoresis.


CONCLUSIONS
Dietary pectins and their degradation products may contribute to the reported protective effects of fruits against colon cancer.
Olano-Martin
Estibaliz
E
School of Food Biosciences, University of Reading, PO Box 226, Whiteknights, Reading Rg6 6AP, U.K.
Rimbach
Gerald H
GH
Gibson
Glenn R
GR
Rastall
Robert A
RA
D000230:Adenocarcinoma / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology*; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology*; D019073:HT29 Cells; D006801:Humans; D009844:Oligosaccharides / Q000494:pharmacology*; D010368:Pectins / Q000494:pharmacology*
D009844:Oligosaccharides; D010368:Pectins; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases