Graduate Institute of Oncology, National Taiwan University College of Medicine, Taipei, Taiwan.
Oncogene. 2012 Jan 26;31(4):458-68. doi: 10.1038/onc.2011.240. Epub 2011 Jun 27.
Matrix metalloproteinases (MMPs) associate with tumor progression and metastasis. We sought to investigate the role of MMP-9 from sublethally irradiated tumor in accelerated pulmonary metastasis of Lewis lung carcinoma (LLC-LM) and the corresponding anti-metastasis strategies in C57BL/6 mice. We used Matrigel-coated Boyden chamber assays and chicken chorioallantoic membrane assays to evaluate the invasion capability of irradiated LLC-LM cells (7.5 Gy), reverse transcription-polymerase chain reaction and the western blot assay to investigate the expression of MMPs by irradiated cells, and small interfering RNA duplexes to inhibit MMP-9 expression. LLC-LM cells differing in MMP-2 or -9 expression were subcutaneously injected into right thighs and the resulting tumors were irradiated (10 Gy × 5) to induce pulmonary metastasis. Radiation significantly enhanced MMP-9 at both the transcriptional and translational levels. MMP-9 siRNA significantly inhibited in vitro radiation-enhanced invasiveness. The number of radiation-accelerated pulmonary metastases was significantly reduced by MMP-9 knockdown and MMP-2/9 knockdown. Reverse transcription-polymerase chain reaction of LLC-LM cells in the blood and lung tissue revealed MMP-9 involvement in radiation-enhanced intravasation. Either higher-dose irradiation (30 Gy × 2) or pretreatment with prototypical MMP-9 inhibitor, zoledronic acid, significantly reduced the number of pulmonary metastases. The viability of irradiated tumor was seen on both positron emission tomography and magnetic resonance imaging, and tumor/serum MMP-9 levels suggested the association of local control of primary tumor and inhibition of time-dependent MMP-9 activities. Our results demonstrate that MMP-9 is crucially involved in radiation-enhanced LLC-LM cell invasiveness in vitro and in pulmonary metastasis from inadequately irradiated primary tumor in vivo.
基质金属蛋白酶（MMPs）与肿瘤的进展和转移有关。我们试图研究亚致死剂量照射的肿瘤来源的 MMP-9 在Lewis 肺癌（LLC-LM）加速肺转移中的作用，以及在 C57BL/6 小鼠中相应的抗转移策略。我们使用 Matrigel 包被的 Boyden 室测定和鸡胚绒毛尿囊膜测定来评估照射的 LLC-LM 细胞（7.5Gy）的侵袭能力，反转录聚合酶链反应和蛋白质印迹测定来研究照射细胞中 MMPs 的表达，以及小干扰 RNA 双链来抑制 MMP-9 的表达。MMP-2 或 MMP-9 表达不同的 LLC-LM 细胞分别皮下注射到右大腿，然后对生成的肿瘤进行照射（10Gy×5）以诱导肺转移。照射显著增强了 MMP-9 在转录和翻译水平上的表达。MMP-9 siRNA 显著抑制了体外照射增强的侵袭性。通过 MMP-9 敲低和 MMP-2/9 敲低，显著减少了辐射加速的肺转移数量。血液和肺组织中 LLC-LM 细胞的反转录聚合酶链反应显示 MMP-9 参与了辐射增强的血管内渗。更高剂量的照射（30Gy×2）或预先使用典型的 MMP-9 抑制剂唑来膦酸，显著减少了肺转移的数量。正电子发射断层扫描和磁共振成像显示照射肿瘤的活力，肿瘤/血清 MMP-9 水平表明与原发性肿瘤局部控制和抑制时间依赖性 MMP-9 活性有关。我们的结果表明，MMP-9 在内皮细胞体外辐射增强 LLC-LM 细胞侵袭性和体内不足量照射原发性肿瘤中肺转移中起着至关重要的作用。
