抑制骨桥蛋白表达降低肺癌侵袭和增殖的机制

目的 探讨抑制骨桥蛋白(OPN)表达降低肺癌细胞株A549侵袭、增殖的机制.方法 构建针对人OPN mRNA干扰质粒pENTRTM/U6-INF(pINF-1)及对照质粒pENTRTM/U6-CTR(pCTR),将其转染A549细胞,Western blot测定OPN、基质金属蛋白酶(MMP)和促分裂素原活化蛋白激酶(MAPK)信号通路相关蛋白的表达;明胶酶谱检测MMP的表达.结果 与空白对照组(1.20±0.15)比较,转染72 h后pINF-1组OPN蛋白表达(0.15±0.04)下降87%,与对照组比差异有统计学意义(P＜0.05).Western blot的结果显示,pINF-1组细胞磷酸化细胞外信号调节激酶1/2(pERK1/2)、磷酸化丝裂原细胞外激酶(pMEK)和MMP-2的表达明显下降,差异有统计学意义(P＜0.01);而MMP-9表达差异无统计学意义(P＞0.05).明胶酶谱结果同样表明pINF-1组MMP-2的表达明显下降(P＜0.01).结论 抑制OPN的表达降低肺癌细胞株A549侵袭力和增殖的机制可能与抑制MAPK信号通路和MMP-2的表达有关.

Abstract：

Objective To explore the mechanism of invasion and proliferation of lung cancer cell line A549 mediated by osteopontin. Methods One double-stranded DNA vectors pENTRTM/U6-INF ( pINF-1 ) targeting the mRNA of human osteopontin ( OPN), and the control vector pENTRTM/U6-CTR (pCTR) mismatching with mRNA of OPN were constructed, and then they were transfected into human A549 cells with high metastatic potentials. Western blotting was used to quantify the protein level of OPN,matrix metalloproteinases (MMPs) and mitogen-activated protein kinases (MAPK). The activity of MMPs was detected by gelatin zymography. Parallel experiments were performed in sextuplicate. Results As compared with control group only transfected with LipofectamineTM 2000, OPN protein level in pINF-1 group was decreased by 87% 72 h after transfection (P ＜0. 05), and no significant difference was found in the group transfected with pCTR. Moreover, the expression levels of phosphorylated extracellular signal-regulated kinases 1/2 (pERK1/2), phosphorylated MAPK/ERK1/2 kinase (pMEK) and MMP-2 protein were also decreased in pINF-1 group (P ＜ 0. 01 ). The activity of MMP-2 but not MMP-9 was decreased significantly in pINF-1 group (P ＜ 0. 01 ). Conclusion OPN plays an important role in metastasis as well as tumor growth of lung cancer cells probably through activation of the MAPK pathways and MMP-2.

The mechanism of decreasing invasion and proliferation of lung cancer cells by RNA interference-mediated knockdown of osteopontin

Objective To explore the mechanism of invasion and proliferation of lung cancer cell line A549 mediated by osteopontin. Methods One double-stranded DNA vectors pENTRTM/U6-INF ( pINF-1 ) targeting the mRNA of human osteopontin ( OPN), and the control vector pENTRTM/U6-CTR (pCTR) mismatching with mRNA of OPN were constructed, and then they were transfected into human A549 cells with high metastatic potentials. Western blotting was used to quantify the protein level of OPN,matrix metalloproteinases (MMPs) and mitogen-activated protein kinases (MAPK). The activity of MMPs was detected by gelatin zymography. Parallel experiments were performed in sextuplicate. Results As compared with control group only transfected with LipofectamineTM 2000, OPN protein level in pINF-1 group was decreased by 87% 72 h after transfection (P ＜0. 05), and no significant difference was found in the group transfected with pCTR. Moreover, the expression levels of phosphorylated extracellular signal-regulated kinases 1/2 (pERK1/2), phosphorylated MAPK/ERK1/2 kinase (pMEK) and MMP-2 protein were also decreased in pINF-1 group (P ＜ 0. 01 ). The activity of MMP-2 but not MMP-9 was decreased significantly in pINF-1 group (P ＜ 0. 01 ). Conclusion OPN plays an important role in metastasis as well as tumor growth of lung cancer cells probably through activation of the MAPK pathways and MMP-2.