Cortactin Mediates Apoptosis of Gastric Epithelial Cells Induced by VacA Protein of Helicobacter pylori.
BACKGROUND
Vacuolating cytotoxin antigen (VacA) is one of the major virulence factors in Helicobacter pylori (H. pylori), which is responsible for cell vacuolar degeneration and apoptotic cell death. A candidate host factor which mediates this process is cortactin, a protein associated with the processes of colonization and adhesion of H. pylori in gastric epithelium.


OBJECTIVE
To investigate the role of cortactin in VacA-induced apoptosis of gastric epithelial cells.


METHODS
Cortactin expression and shRNA lentiviral constructs were developed and transduced into the human gastric cancer cell line, AGS. VacA protein was purified from H. pylori cultures, acid-activated, and co-incubated with the transduced cell populations. Apoptosis was detected by flow cytometry, and the levels of the pro- and anti-apoptotic proteins Bax and Bcl-2 were determined by Western blot.


RESULTS
Acid-activated purified VacA induced apoptosis in the parental AGS cells. Increased expression of cortactin (AGS/cortactin) led to a greater percentage of cells undergoing apoptosis. In contrast, knockdown of cortactin with shRNA (AGS/cortactin-shRNA) decreased the percentage of apoptotic cells. The protein levels of pro- and anti-apoptotic proteins Bax and Bcl-2 were increased and decreased in AGS/cortactin cells relative to the parental AGS cells. In the AGS/cortactin-shRNA cells, Bax protein levels were decreased, while Bcl-2 protein was increased.


CONCLUSIONS
The results indicate that cortactin is involved in the regulation of apoptosis induced by VacA in gastric cells.
Department of Gastroenterology, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Chongqing, 400042, China.
Hui
H
Chang
Department of Gastroenterology, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Chongqing, 400042, China.
Dongfeng
D
Chen
Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, The Third Military Medical University, Chongqing, China.
Bosheng
B
Ni
Cadre's Ward of Bethune International Peace Hospital, PLA, Shijiazhuang City, Hebei Province, China.
Qianfei
Q
Zuo
Cadre's Ward of Bethune International Peace Hospital, PLA, Shijiazhuang City, Hebei Province, China.
Chunhua
C
Wang
Department of Gastroenterology, Guizhou Aerospace Hospital, Zunyi City, Guizhou Province, China.
Ran
R
Han
Department of Gastroenterology, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Chongqing, 400042, China. tiandaochouqin99@hotmail.com.
Chunhui
C
Lan
D017209:Apoptosis; D001426:Bacterial Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D051356:Cortactin / Q000235:genetics / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D005753:Gastric Mucosa / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D006801:Humans; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D034622:RNA Interference; D015398:Signal Transduction; D014161:Transduction, Genetic; D014162:Transfection; D051028:bcl-2-Associated X Protein / Q000378:metabolism
C494826:BAX protein, human; C000595707:BCL2 protein, human; D001426:Bacterial Proteins; C495868:CTTN protein, human; D051356:Cortactin; D019253:Proto-Oncogene Proteins c-bcl-2; C074689:VacA protein, Helicobacter pylori; D051028:bcl-2-Associated X Protein
Apoptosis; Bax; Bcl-2; Cortactin; Helicobacter pylori; VacA