Department of Surgical Oncology, Osaka City University Graduate School of Medicine, Abeno-ku, Osaka, Japan.
PLoS One. 2013 May 17;8(5):e62310. doi: 10.1371/journal.pone.0062310. Print 2013.
Epithelial mesenchymal transition (EMT) is considered to be correlated with malignancy of cancer cells and responsible for cancer invasion and metastasis. We previously reported that distant metastasis was associated with hypoxia in gastric cancer. We therefore investigated the effect of hypoxic condition on EMT of gastric cancer cells. Gastric cancer cells were cultured in normoxia (21% O2) or hypoxia (1% O2) for 24 h. EMT was evaluated as the percentage of spindle-shaped cells in total cells. Effect of transforming growth factor β1 (TGFβ1) or tyrosine kinase inhibitors on the EMT was evaluated. The expression level of TGFβ1 and TGFβR was evaluated by real time RT-PCR. The TGFβ1 production from cancer cells was measured by ELISA. Hypoxia stimulated EMT of OCUM-2MD3 and OCUM-12 cells, but not that of OCUM-2M cells. The expression level of TGFβ1 mRNA under hypoxia was significantly higher than that under normoxia in all of three cell lines. The expression level of TGFβR mRNA was significantly increased by hypoxia in OCUM-2MD3 cells, but not in OCUM-2M cells. TGFβR inhibitor, SB431542 or Ki26894, significantly suppressed EMT of OCUM-2MD3 and OCUM-12. TGFβ1 production from OCUM-2MD3 and OCUM-12 cells was significantly increased under hypoxia in comparison with that under normoxia. These findings might suggest that hypoxia stimulates the EMT of gastric cancer cells via autocrine TGFβ/TGFβR signaling.
上皮间质转化（EMT）被认为与癌细胞的恶性程度有关，并且与癌症的侵袭和转移有关。我们之前报道过胃癌的远处转移与缺氧有关。因此，我们研究了缺氧条件对胃癌细胞 EMT 的影响。将胃癌细胞在常氧（21% O2）或缺氧（1% O2）条件下培养 24 小时。通过总细胞中纺锤形细胞的百分比评估 EMT。评估转化生长因子β1（TGFβ1）或酪氨酸激酶抑制剂对 EMT 的影响。通过实时 RT-PCR 评估 TGFβ1 和 TGFβR 的表达水平。通过 ELISA 测量癌细胞中 TGFβ1 的产生。缺氧刺激 OCUM-2MD3 和 OCUM-12 细胞的 EMT，但不刺激 OCUM-2M 细胞的 EMT。在三种细胞系中，缺氧下 TGFβ1 mRNA 的表达水平明显高于常氧下的表达水平。在 OCUM-2MD3 细胞中，缺氧显著增加了 TGFβR mRNA 的表达水平，但在 OCUM-2M 细胞中没有。TGFβR 抑制剂 SB431542 或 Ki26894 显著抑制了 OCUM-2MD3 和 OCUM-12 的 EMT。与常氧相比，缺氧下 OCUM-2MD3 和 OCUM-12 细胞中 TGFβ1 的产生明显增加。这些发现表明缺氧通过自分泌 TGFβ/TGFβR 信号通路刺激胃癌细胞的 EMT。
