囊性纤维化跨膜转导调节子(CFTR)对肺癌A549细胞恶性特性的影响研究

摘要

背景与目的 肺癌发病率逐年上升,有必要寻找新型的治疗靶点,而最新研究发现囊状纤维化跨膜转导调节子(cystic fibrosis transmembrane conductance regulator, CFTR)与多种肿瘤的发生和恶性转化有关.本研究探讨CFTR对肺癌A549细胞恶性特性的影响.方法 应用CCK8细胞增殖实验、细胞划痕实验、Transwell细胞侵袭实验以及克隆形成实验等方法分别检测CFTR的表达对非小细胞肺癌A549细胞的增殖、迁移、侵袭等细胞恶性特性的影响.同时通过免疫印迹(Western blot)分析CFTR基因表达对肿瘤干细胞相关转录因子表达的影响.结果 过表达CFTR基因显著抑制A549细胞的增殖、迁移、侵袭和克隆形成等肿瘤恶性特征,而RNA干扰A549细胞CFTR的表达导致细胞上述特征的明显增强.免疫印迹实验进一步发现CFTR基因过表达抑制A549细胞中干细胞相关转录因子SOX2和OCT3/4,以及细胞表面CD133蛋白的表达;相反,RNA干扰A549细胞中CFTR基因的表达增加SOX2、OCT4和CD133的表达.然而,免疫印迹和流式细胞术发现CFTR基因表达对A549细胞肺癌干细胞标志乙醛脱氢酶1的表达和阳性细胞数量无显著影响.结论 CFTR基因在肺癌A549细胞中具有抑制细胞恶性特征的作用,提示其可能是肺腺癌治疗的一个新的靶点,但其对其他肺腺癌细胞的作用与分子机制还有待进一步研究.%Background and objective The incidence of lung cancer is gradually increased, and the cystic fi-brosis transmembrane conductance regulator (CFTR) has recently demonstrated to have an implication in the deonco-genesis and malignant transformation of many types of cancers. The aim of this study is to investigate impacts of CFTR on the malignant features of lung adenocarcinoma A549 cells. Methods The capacity of cell proliferation, migration, invasion and clonogenicity of non-small cell lung cancer A549 cells were detected by CCK8 cell proliferation assay, cell scratch assay,Transwell cell invasion assay and clone formation assay,respectively.Meanwhile,the effect of CFTR gene on the expression of cancer stem cell related transcriptional factors was also detected by immunoblotting (West-ern blot)assay.Results An overexpression of CFTR gene in A549 cells significantly inhibited the malignant capacity of A549 cells, including potencies of cell proliferation, migration, invasion and colony formation; while knockdown of CFTR gene expression by RNA interference in A549 cells resulted in an opposite effect seen in above cells overexpress-ing CFTR gene.Mechanistically,immunoblotting assay further revealed that the ectopic expression of CFTR gene led an inhibitory expression of stem cell-related transcriptional factors SOX2 and OCT3/4, and cancer stem cell surface marker CD133 in A549 cells, while a knockdown of CFTR expression yielded a moderately increased expression of these gene.However,an alteration of CFTR gene expression had neither effect on the expression of putative lung can-cer stem cell marker aldehyde dehydrogenase1 (ALDH1), nor the frequency of ALDH1A-positive cells in A549 cells, as ascertained by the immunoblotting assay and cytometry analysis, respectively. Conclusion The CFTR exhibited an inhibitory role in the malignancy of lung adenocarcinoma A549 cells, suggesting that it may be a novel potential target for lung cancer treatment. However, its functions in other lung adenocarcinoma cell lines and its underlying molecular mechanisms require further investigation.