Jing Shao-Wu, Wang Ya-Di, Kuroda Masahiro, Su Jing-Wei, Sun Guo-Gui, Liu Qing, Cheng Yun-Jie, Yang Cong-Rong
Department of Radiotherapy, the Fourth Hospital of Hebei Medical University, Shijiazhuang 050011, China.
Acta Med Okayama. 2012;66(5):399-407. doi: 10.18926/AMO/48964.
Hypoxia-inducible factor-1α (HIF-1α) has been found to enhance tumor invasion and metastasis, but no study has reported its action in esophageal carcinoma. The goal of this study was to explore the probable mechanism of HIF-1α in the invasion and metastasis of esophageal carcinoma Eca109 cells in vitro and in vivo. mRNA and protein expression of HIF-1α, E-cadherin and matrix metalloproteinase-2 (MMP-2) under hypoxia were detected by RT-PCR and Western blotting. The effects of silencing HIF-1α on E-cadherin, MMP-2 mRNA and protein expression under hypoxia or normoxia were detected by RT-PCR and Western blotting, respectively. The invasive ability of Eca109 cells was tested using a transwell chambers. We established an Eca109-implanted tumor model and observed tumor growth and lymph node metastasis. The expression of HIF-1α, E-cadherin and MMP-2 in xenograft tumors was detected by Western blotting. After exposure to hypoxia, HIF-1α protein was up-regulated, both mRNA and protein levels of E-cadherin were down-regulated and MMP-2 was up-regulated, while HIF-1α mRNA showed no significant change. SiRNA could block HIF-1α effectively, increase E-cadherin expression and inhibit MMP-2 expression. The number of invading cells decreased after HIF-1α was silenced. Meanwhile, the tumor volume was much smaller, and the metastatic rate of lymph nodes and the positive rate were lower in vivo. Our observations suggest that HIF-1α inhibition might be an effective strategy to weaken invasion and metastasis in the esophageal carcinoma Eca109 cell line.
缺氧诱导因子-1α（HIF-1α）已被发现可增强肿瘤侵袭和转移，但尚无研究报道其在食管癌中的作用。本研究的目的是探讨HIF-1α在体外和体内对食管癌Eca109细胞侵袭和转移的可能机制。通过RT-PCR和蛋白质免疫印迹法检测缺氧条件下HIF-1α、E-钙黏蛋白和基质金属蛋白酶-2（MMP-2）的mRNA和蛋白表达。分别通过RT-PCR和蛋白质免疫印迹法检测在缺氧或常氧条件下沉默HIF-1α对E-钙黏蛋白、MMP-2 mRNA和蛋白表达的影响。使用Transwell小室检测Eca109细胞的侵袭能力。我们建立了Eca109移植瘤模型，观察肿瘤生长和淋巴结转移情况。通过蛋白质免疫印迹法检测异种移植瘤中HIF-1α、E-钙黏蛋白和MMP-2的表达。暴露于缺氧环境后，HIF-1α蛋白上调，E-钙黏蛋白的mRNA和蛋白水平均下调，MMP-2上调，而HIF-1α mRNA无明显变化。SiRNA可有效阻断HIF-1α，增加E-钙黏蛋白表达并抑制MMP-2表达。沉默HIF-1α后侵袭细胞数量减少。同时，体内肿瘤体积更小，淋巴结转移率和阳性率更低。我们的观察结果表明，抑制HIF-1α可能是削弱食管癌Eca109细胞系侵袭和转移的有效策略。
