Cyclin D1调控肺癌细胞的浸润和转移

Cyclin D1 regulates lung cancer invasion and metastasis

Cyclin D1作为细胞周期的一个调控因子,许多肿瘤细胞都过表达Cyclin D1基因,比如肺癌、乳腺癌、甲状腺癌等。但是Cyclin D1在肿瘤细胞浸润和转移中的作用报道较少。本研究旨在研究Cyclin D1对肺癌细胞浸润、转移的调控作用。以肺腺癌细胞A549(高表达Cyclin D1)和肺鳞癌细胞SK-MES-1(低表达Cyclin D1)为研究对象。取裸鼠尾静脉注射A549或SK-MES-1细胞,4周后处死,从肺脏中分离出肿瘤细胞再接种另外的裸鼠,如此经过2次循环接种构建裸鼠高转移动物模型。向A549细胞转染Cyclin D1的干扰RNA抑制Cyclin D1的表达,同时向SK-MES-1细胞转染Cyclin D1的表达载体促进Cyclin D1的表达,随后通过细胞迁移实验观察基因处理后A549和SK-MES-1细胞的转移能力变化。用Western blot检测亲本细胞、不同转移层次裸鼠的癌组织中Cyclin D1和WNT/TCF信号通路相关蛋白因子的表达。结果显示,随着转移次数增加,从动物癌组织中分离出的癌细胞转移能力显著增强,Cyclin D1表达也明显升高;在A549细胞中,干扰Cyclin D1的表达可使细胞迁移能力变弱;在SK-MES-1细胞中,过表达Cyclin D1可使细胞迁移能力增强。高转移肺癌动物模型肿瘤组织中β-catenin、LEF、TCF蛋白表达高于低转移肿瘤组织,而二者的上述蛋白表达均高于亲本肺癌细胞。以上结果提示,Cyclin D1的表达与肺癌的浸润和转移密切相关,推测WNT/TCF信号通路能够促进Cyclin D1的表达。

Cyclin D1, as a regulatory factor in cell cycle, is highly expressed in many tumors, such as lung cancer, breast cancer and thyroid cancer. The aim of the present study was to study the role of Cyclin D1 in invasion and metastasis of lung cancer cells. Lung adenocarcinoma cell line A549 and squamous cell line SK-MES-1 were selected as the objects, because A549 expresses Cyclin D1 highly, and SK-MES-1 expresses lowly. Nude mice were injected with A549 or SK-MES-1 via tail vein, and were sacrificed after 4 weeks for cancer tissue isolation. The harvested cancer cells were reinjected into another nude mouse. After one more time of such seeding, highly metastatic lung cancer model was established. After A549 and SK-MES-1 were transfected with Cyclin D1 RNAi and expression vector respectively, transwell migration assay was used to analyze transferring capacity of lung cancer cells. Western blot was used to detect Cyclin D1 and WNT/TCF pathway proteins expressions in parental cell lines and cancer tissue from metastasis model animals. The results showed that, along with the increase of seeding times, lung cancer cells from model animals, no matter A549 or SK-MES-1, exhibited augmented metastasis activity and up-regulated Cyclin D1 expression. The transferring capacity was weakened significantly in A549 cells where the Cyclin D1 was interfered by RNAi, and it was enhanced significantly in SK-MES-1 cells which were transfected with the expression vector of Cyclin D1. The expressions of WNT/TCF pathway proteins, including β-catenin, lymphoid enhancer-binding factor （LEF） and T cell factor （TCF）, increased significantly in highly metastatic model animals. The parental cell lines showed lower expressions of WNT/TCF pathway proteins compared with cancer tissue from metastasis model animals. These results suggest that Cyclin D1 is closely related with the invasion and metastasis of lung cancer cells, and the WNT/TCF signal pathway may promote the expression of Cyclin D1.