Apoptotic effect of Helicobacter pylori on oesophageal squamous-cell carcinoma cells in vitro.
BACKGROUND
The relationship between Helicobacter pylori (Hp) infection and oesophageal squamous-cell carcinoma (ESCC) risk is still inconclusive. Our previous study found an inverse association between the two, but its mechanism is still unknown. Thus, we conducted in vitro studies to clarify the issue.


METHODS
One ESCC (CE 81T/VGH) cell line was co-cultured with Hp, using one gastric adenocarcinoma (AGS) cell line as the control. Hp-induced cell apoptosis was determined by flow cytometry, terminal transferase-mediated dUTP nick end labelling (TUNEL) assay and staining; caspase-3 protein expressions in cell lysates were detected by Western immunoblot.


RESULTS
Increased apoptosis was found in CE 81T/VGH, but not in AGS cells, by flow cytometry and TUNEL assay after being co-cultured with Hp at the multiplicity of infection of 1/100 (but not at 1/400) for 36 h. The amount of activated caspase-3 (17/19 kDa) also increased in CE 81T/VGH, but not in AGS cells, after co-culturing with Hp at MOI of 1/100 for 36 h. The results were confirmed by triplicate experiments in which the different apoptotic assays remained consistent.


CONCLUSIONS
Our study provides indirect evidence of the inverse association between Hp infection and ESCC risk, which is possibly due to Hp-induced apoptosis in ESCC cells. A further in vivo study is necessary to confirm our findings.
Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
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IC
Wu
M-T
MT
Wu
Y-K
YK
Chen
M-C
MC
Hsu
S-H
SH
Chou
C-H
CH
Lee
J-T
JT
Shiea
I-L
IL
Wu
C-T
CT
Huang
D-C
DC
Wu
D017304:Annexin A5 / Q000032:analysis; D017209:Apoptosis; D015415:Biomarkers / Q000032:analysis; D002294:Carcinoma, Squamous Cell / Q000382:microbiology* / Q000473:pathology; D053148:Caspase 3 / Q000032:analysis; D045744:Cell Line, Tumor; D004938:Esophageal Neoplasms / Q000382:microbiology* / Q000473:pathology; D005434:Flow Cytometry; D016481:Helicobacter Infections / Q000473:pathology; D016480:Helicobacter pylori / Q000502:physiology*; D006801:Humans; D020287:In Situ Nick-End Labeling
D017304:Annexin A5; D015415:Biomarkers; D053148:Caspase 3