Effect of physiological concentrations of vitamin C on gastric cancer cells and Helicobacter pylori.
BACKGROUND
Gastric juice vitamin C may be protective against gastric carcinogenesis but concentrations are significantly reduced by Helicobacter pylori infection. We investigated the in vitro effects of vitamin C at concentrations comparable with those found in gastric juice on gastric cancer cells and H pylori.


METHODS
Gastric cancer cell lines and various H pylori strains were treated with L-ascorbic acid for up to 72 hours. Cell viability, and protein and DNA synthesis were determined. Flow cytometry was used for assessment of H pylori adherence, cell cycle distribution, and apoptosis. H pylori growth and its haemagglutination activity were determined using viability count and microtitration assay.


RESULTS
Vitamin C induced a significant dose dependent growth inhibition of gastric AGS and MKN45 cells but this effect was significantly reduced at levels similar to those in gastric juice of H pylori infected patients (<50 microM). Although vitamin C had no obvious effect on H pylori growth, haemagglutination activity, or adherence ability to gastric AGS cells compared with untreated controls, it significantly enhanced H pylori associated apoptosis and induced cell cycle arrest in these cells.


CONCLUSIONS
Vitamin C may inhibit gastric cancer cell growth and alter H pylori induced cell cycle events at concentrations comparable with those in gastric juice, but has no effect on H pylori growth or pathogenicity. However, the inhibitory effect on gastric cancer cells was lost at vitamin C concentrations found in patients with H pylori infection.
Zhang
Z-W
ZW
Digestive Diseases Research Centre, St Bartholomew's and the Royal London School of Medicine and Dentistry, London, UK. z.w.zhang@bristol.ac.uk
Abdullahi
M
M
Farthing
M J G
MJ
D000230:Adenocarcinoma / Q000473:pathology / Q000517:prevention & control*; D001205:Ascorbic Acid / Q000502:physiology*; D001422:Bacterial Adhesion / Q000502:physiology; D002455:Cell Division; D005434:Flow Cytometry / Q000379:methods; D005750:Gastric Juice / Q000737:chemistry*; D016481:Helicobacter Infections / Q000517:prevention & control*; D016480:Helicobacter pylori / Q000254:growth & development / Q000472:pathogenicity / Q000502:physiology; D006384:Hemagglutination / Q000502:physiology; D006386:Hemagglutination Tests; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007413:Intestinal Mucosa / Q000382:microbiology; D013274:Stomach Neoplasms / Q000473:pathology / Q000517:prevention & control*; D014407:Tumor Cells, Cultured
D001205:Ascorbic Acid