Hypoxia upregulates adhesion ability to peritoneum through a transforming growth factor-beta-dependent mechanism in diffuse-type gastric cancer cells.
Gastric cancer cells leaving the primary tumour are exposed to low oxygen levels in the peritoneal cavity; however, peritoneal metastatic phenotypes of hypoxic cancer cells remain unclear. We used 6 gastric cancer cell lines, including 3 diffuse-type gastric cancer (DGC) and 3 non-DGC cell lines. Using adhesion assay, we examined the effect of hypoxic conditions on their ability to adhere to peritoneal components. The expression level of transforming growth factor-beta (TGF-beta) and integrins mRNA of cancer cells was examined using reverse transcriptase-polymerase chain reaction. We further examined the effect of anti-integrin neutralising antibodies and a TGF-beta receptor inhibitor on the adhesion ability of hypoxic cancer cells. The binding ability of DGC cells was higher than that of non-DGC cells; it was significantly increased by hypoxic (1% O2) conditions compared to normoxic (21% O2) conditions. In contrast, no remarkable change in adhesion ability was observed in the non-DGC cells under normoxic and hypoxic conditions. Integrins and TGF-beta expression of hypoxic DGC cells was significantly higher than that of normoxic cells. TGF-beta increased the adhesion ability and alpha2-, alpha3- and alpha5-integrin expression of hypoxic DGC cells, whereas the TGF-beta receptor inhibitor decreased them. Neutralising antibodies against alpha2-, alpha3- and alpha5-integrin inhibited the adhesion ability of DGC cells. These findings suggested that hypoxic conditions promote the adhesion of DGC cells to the peritoneum. The upregulation of alpha2-, alpha3- and alpha5-integrin by TGF-beta under hypoxic conditions may be one of the mechanisms responsible for the high metastatic potential of hypoxic DGC cells to the peritoneum.
Noda
Satoru
S
Department of Surgical Oncology, Osaka City University, Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka, Japan.
Yashiro
Masakazu
M
Nshii
Takafumi
T
Hirakawa
Kosei
K
D057134:Antibodies, Neutralizing / Q000494:pharmacology; D001549:Benzamides / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D015687:Cell Hypoxia / Q000502:physiology*; D045744:Cell Line, Tumor; D004149:Dioxoles / Q000494:pharmacology; D006801:Humans; D016023:Integrins / Q000276:immunology / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism*; D010534:Peritoneal Neoplasms / Q000556:secondary*; D010766:Phosphorylation; D012333:RNA, Messenger / Q000378:metabolism; D018125:Receptors, Transforming Growth Factor beta / Q000037:antagonists & inhibitors; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051899:Smad2 Protein / Q000378:metabolism; D051900:Smad3 Protein / Q000378:metabolism; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology; D016212:Transforming Growth Factor beta / Q000378:metabolism / Q000494:pharmacology*
C459179:4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamide; D057134:Antibodies, Neutralizing; D001549:Benzamides; D004149:Dioxoles; D016023:Integrins; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D018125:Receptors, Transforming Growth Factor beta; C497790:SMAD3 protein, human; D051899:Smad2 Protein; D051900:Smad3 Protein; D016212:Transforming Growth Factor beta