Department of Oncology, Tangdu Hospital, Xi'an, China.
Cancer Sci. 2010 Jul;101(7):1653-60. doi: 10.1111/j.1349-7006.2010.01592.x. Epub 2010 Apr 19.
It has been reported that the 67-kDa laminin receptor (67LR) is implicated in cancer metastasis. We recently showed that 37LRP, the 67LR precursor, is a hypoxia-inducible factor 1 (HIF-1) target gene exposed to hypoxia in gastric cancer. Here, we investigated the role of 67LR in hypoxic metastasis and invasion in gastric cancer. Immunohistochemical analysis, western blotting, and RT-PCR assays revealed that 67LR was highly expressed in metastatic gastric cancers in vivo. Knockdown of the 67LR protein by RNA interference significantly decreased the adhesive, invasive, and in vivo metastatic abilities of the gastric cancer cell lines SGC7901 and MKN-45. Western blot analysis showed that 67LR increased the expression of urokinase-type plasminogen activator (uPA) and matrix metalloproteinase (MMP)-9, and decreased tissue inhibitor of matrix metalloproteinase (TIMP)-1 protein. We further showed that hypoxia induced 67LR expression in a time-dependent manner and this induction was inhibited by HIF-1 small-interfering (si) RNA. Both ERK and JNK inhibitors significantly inhibited hypoxia-induced expression of 67LR and the subsequent expression of uPA and MMP 9. SiRNA against 67LR or antibody against MMP9 and uPA significantly inhibited hypoxia-induced in vitro invasive ability. Taken together, these results reveal that 67LR promotes the invasive and metastatic ability of the gastric cancer cells through increasing uPA and MMP 9 expression, with involvement of the ERK and JNK signal pathway in hypoxia-induced 67 LR expressions and subsequent uPA and MMP9 expression.
据报道,67 千道尔顿层粘连蛋白受体(67LR)与癌症转移有关。我们最近表明,37LRP,即 67LR 的前体,是在缺氧条件下诱导的缺氧诱导因子 1(HIF-1)靶基因在胃癌中。在这里,我们研究了 67LR 在缺氧转移和侵袭中的作用在胃癌中。免疫组织化学分析、western blot 和 RT-PCR 检测显示,67LR 在体内转移性胃癌中高度表达。RNA 干扰敲低 67LR 蛋白显著降低了胃癌细胞系 SGC7901 和 MKN-45 的粘附、侵袭和体内转移能力。Western blot 分析显示,67LR 增加了尿激酶型纤溶酶原激活物(uPA)和基质金属蛋白酶(MMP)-9 的表达,并降低了组织金属蛋白酶抑制剂(TIMP)-1 的蛋白表达。我们进一步表明,缺氧以时间依赖性方式诱导 67LR 的表达,这种诱导被 HIF-1 小干扰(si)RNA 抑制。ERK 和 JNK 抑制剂均显著抑制缺氧诱导的 67LR 表达以及随后的 uPA 和 MMP9 表达。67LR 的 siRNA 或 MMP9 和 uPA 的抗体显著抑制了缺氧诱导的体外侵袭能力。总之,这些结果表明,67LR 通过增加 uPA 和 MMP9 的表达促进胃癌细胞的侵袭和转移能力,涉及 ERK 和 JNK 信号通路在缺氧诱导的 67LR 表达和随后的 uPA 和 MMP9 表达中。