FLNA在鼻咽癌发生中的作用及其可能的分子机制

FLNA suppresses nasopharyngeal carcinoma cell proliferation and migration partially through an MMP-9-dependent mechanism

目的:探讨细丝蛋白A(filamin A,FLNA)在鼻咽癌中的表达水平及其过表达对鼻咽癌(nasopharyngeal carcinoma,NPC)细胞生物表型的影响。方法:收集2008年1月至2008年12月唐山市人民医院病理科活检取得并经病理证实的新鲜NPC组织标本63例及21例距其癌组织边缘2 cm以上且镜下未见癌浸润的正常鼻咽组织(对照组),采用免疫组织化学及Western blotting方法检测NPC组织及正常鼻咽组织中FLNA及MMP-9蛋白的表达。以慢病毒转染建立FLNA过量表达的NPC CNE2细胞株,采用RT-PCR及Western blotting检测转染后NPC CNE2细胞株中FLNA的表达变化;MTT法检测FLNA蛋白过量表达对NPC细胞增殖的影响,Transwell实验检测CNE2细胞的侵袭能力。结果:FLNA蛋白在NPC组织中的阳性表达率明显低于正常鼻咽组织(36.5%vs 66.7%,P<0.05),其在NPC组织的相对表达量较正常鼻咽组织的相对表达量明显降低[(0.378±0.031)vs(0.835±0.078),P<0.05],FLNA蛋白的表达水平与NPC T分期、有无淋巴结转移、临床分期以及组织分级有关(P<0.05)。FLNA蛋白高表达的CNE2细胞其增殖能力明显减弱、侵袭转移能力明显降低、MMP-9蛋白表达量明显下调。结论:NPC组织中FLNA蛋白表达明显降低可能是鼻咽黏膜恶性转变的重要生物学标志,对预测NPC发生、浸润、转移有重要意义。

Objective： This study aimed to determine the expression of filamin A（ FLNA） in nasopharyngeal carcinoma and evaluate the effect of FLNA overexpression on nasopharyngeal cancer cell proliferation and migration in vitro. Methods： Fresh nasopharyngeal cancer（ NPC,n = 63） and non-cancer nasopharyngeal tissue surrounding but at least 2 cm from the tumor proper（ n = 21） specimens were collected from NPC patients who were treat in the Department of Pathology in Tangshan Municipal People＇s Hospital between January,2008 and December,2008.The presence and quantity of FLNA protein in these specimens was assessed by immunohistochemistry and Western blotting analysis. To evaluate the effect of FLNA on NPC cell proliferation and migration in vitro and elucidate the possible underlying mechanisms,nasopharyngeal cancer CNE2 cells were infected with a lentiviral vector carrying the human FLNA gene（ pLenti6-FLNA） or a control lentiviral vector and the cell viability,migration capacity and MMP-9 protein content of the vector-infected cells were assessed by MTT assay,Transwell assay and Western blotting analysis respectively. Result： FLNA protein was detected positive in 35. 6 %（ 23 /63） of nasopharyngeal carcinoma specimens and 66. 7 %（ 14 /21） of non-carcinoma specimens（ P〈 0. 05）. The relative amount of FLNA protein in nasopharyngeal cancer tissue was significantly lower than in normal nasopharyngeal tissue（〈 P 0. 05）. The level of FLNA protein was correlated with T stages,lymph node metastasis,clinic stage and histological grade（ P〈 0. 05）.Overexpression of FLNA resulted in significant decreases in proliferation,migration and invasion,and MMP-9 protein content CNE2 cells in vitro（ P 〈0. 05）. Conclusion： FLNA may be a negative regulator to nasopharyngeal cancer growth and invasion. This negative effect of FLNA is mediated,at least partially,by an MMP-9-dependent mechanism.