转录因子MKL1通过激活CCNB2转录促进肺癌转移

MKL1 potentiates lung cancer cell oncogenesis and migration by activating CCNB2 transcription

目的 :在人肺腺癌细胞中,研究转录因子MKL1是否参与了肺肿瘤细胞的迁移和侵袭过程,并且调控的信号通路是否涉及细胞周期蛋白2(CCNB2)活性的改变。方法:在肺癌细胞中感染MKL1病毒构建稳定细胞系,分析抑制MKL1表达对肿瘤细胞生长及迁移能力的影响;Real-time PCR(RT-PCR)法检测内源MKL1缺失对CCNB2 m RNA水平的影响;荧光素酶报告基因法分析干扰内源MKL1对CCNB2启动子表达的作用。结果:软琼脂种植实验显示当MKL1表达被抑制后,形成的集落明显减少,表明MKL1能够促进肿瘤恶化。通过绘制生长曲线发现感染组MKL1表达被抑制后,细胞增殖能力下降。荧光素酶报告基因实验显示MKL1的小RNA干扰转染细胞后,CCNB2启动子的表达显著降低,抑制率达70%。RT-PCR实验显示MKL1干扰后CCNB2的m RNA水平明显降低。以上差异均有统计学意义(P<0.05)。结论 :稳定敲除MKL1的肺癌细胞系出现生长减慢、侵袭能力降低等特性。MKL1干扰后CCNB2的转录活性和m RNA水平都显著降低。本研究为早期肺癌的诊断和治疗提供了依据。

Objective：To investigate the migration and invasion of lung neoplasm potentiated by MKL1 and the change of CCNB2 activity involved in signal pathway. Methods：Lung cancer cells were infected with lentivirus carrying indicated sh RNAs and effect of MKL1 inhibition on migration and invasion of lung cancer cells was measured. Small interfering RNA was transfected to suppress the expression of MKL1,RT-PCR was performed to examine CCNB2 m RNA level,and luciferase reporter assays was to assess the effect of MKL1 deletion on the promoter activities of CCNB2. Results：Cell colony formation was diminished by soft agar clonogenic assay and cell proliferation was reduced when MKL1 was silenced by siRNA. MKL1 depletion directly repressed CCNB2 transcription,and the inhibition was up to 70%. RT-PCR showed great depression of CCNB2 m RNA by the interference of MKL1. Difference was of significance（P 〈 0.05）. Conclusion：Depletion of MKL1 by sh RNA significantly hampered the migration and invasion of lung cancer cell. MKL1 depletion inhibited CCNB2 transcriptional activity and repressed m RNA expression. The study provided early-stage markers for lung cancer diagnosis and treatment.