nm23-H1基因逆转人高转移大细胞肺癌细胞L9981转移表型的分子机制

Molecular Mechanism of Reversing Metastatic Phenotype in Human High-metastatic Large Cell Lung Cancer Cell Line L9981 by nm23-H1

背景与目的:nm23-H1基因已被证明是转移抑制基因,转染野生型nm23-H1基因可以逆转肿瘤的恶性转移表型,但是nm23-H1基因抑制或逆转肺癌转移的分子机制却知之甚少,我们在建立转nm23-H1基因的人高转移大细胞肺癌细胞株L9981-nm23-H1的基础上,进一步探讨nm23-H1基因抑制肺癌转移的分子机制。方法:应用MTT法和改良的Boyden小室法分析转基因前后细胞的体外增殖能力及体外侵袭力的变化,体内实验分析转基因前后细胞在裸鼠体内的成瘤性及肺转移能力的改变,同时应用RT-PCR和Westernblot分别检测各组细胞中转移相关基因β-catenin、E-Cadherin、CD44S、CD44V6、MMP-2、TIMP-1、VEGF、基因mRNA及蛋白表达水平。结果:(1)转基因细胞株L9981-nm23-H1的体外增殖能力[(0%vs.(19.5±2.9)%]、克隆形成能力(10.3±0.7vs.21.7±1.3)及侵袭力显著低于L9981细胞(31.0±3.0vs.151.0±6.3)(P<0.01);(2)nm23-H1基因在裸鼠体内的抑瘤率显著增高(82.6%vs.0%),且转染nm23-H1基因的L9981细胞裸鼠体内移植瘤肺转移显著降低(0%vs.100%)(P<0.01);(3)nm23-H1基因能够上调β-catenin、E-Cadherin、TIMP-1基因mRNA及蛋白表达,下调VEGF、CD44V6和MMP-2基因mRNA及蛋白表达(P<0.01);(4)nm23-H1表达上调CD44S基因mRNA表达(P<0.01),而对其蛋白表达?

BACKGROUND & OBJECTIVE: nm23-H1, a tumor metastasis suppressive gene, can reverse tumor metastasis phenotype. But the molecular mechanism of nm23-H1 in inhibiting or reversing metastasis of lung cancer is unclear. This study was to explore the molecular mechanism of nm23-H1 in reversing metastasis phenotype of lung cancer. METHODS: nm23-H1 gene and pLXSN were seperately transfected into human lung cancer cell line L9981. Proliferation of L9981, L9981-pLXSN, and L9981-nm23-H1 cells was detected by MTT assay, cell invasive ability was detected by modified Boyden chamber. Tumorigenesis and experimental lung metastasis were determined in vivo. mRNA and protein levels of β-catenin, E-Cadherin, CD44S, CD44V6, matrix metalloproteinase-2 (MMP-2), tissue inhibitor of metalloproteinase-1 (TIMP-1), and vascular endothelial growth factor (VEGF) were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. RESULTS: (1)Cell proliferation, clone formation, and invasive ability were significantly lower in L9981-nm23-H1 cells than in L9981 cells [(19.5±2.9)% vs. 100%, 10.3±0.7 vs. 21.7±1.3, 31.0±3.0 vs. 151.0±6.3, P<0.01]. (2) The inhibitory rate of tumorigenesis of nude mice was significantly higher in L8891-nm23-H1 group than in L9981 group (85.6% vs. 0%, P<0.001); the lung metastatic rate was significantly lower in L9981-nm23-H1 group than in L9981 group (0% vs. 100%, P<0.001). (3)nm23-H1 up-regulated mRNA and protein levels of β-catenin, E-Cadherin, and TIMP-1, and down-regulated levels of MMP-2, CD44V6, and VEGF (P<0.01). (4) nm23-H1 up-regulated mRNA level of CD44s, protein level of CD44s didn't change (P>0.05). CONCLUSION: nm23-H1 gene can reverse malignant and metastatic phenotype of L9981 cells through regulating the expressions of lung cancer metastasis-related genes.