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.
Department of Surgical Oncology, Osaka City University, Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka, Japan.
Satoru
S
Noda
Masakazu
M
Yashiro
Takafumi
T
Nshii
Kosei
K
Hirakawa
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