p120-catenin通过Kaiso在转录水平上调控肺癌细胞系LTEP-a-2中β-catenin的表达

p120-catenin regulates β-catenin expression in lung cancer cell LTEP-a-2

目的:探讨肺癌细胞系中p120-catenin(p120ctn)调节β-catenin转录的分子机制。推测p120ctn可能通过其分子伴侣Kaiso进而发挥调节β-catenin转录的重要功能。方法:转染、Real-Time PCR、BSP测序、染色质免疫共沉淀及蛋白质免疫共沉淀等多种研究方法验证我们的推测。结果:对肺癌细胞系中β-catenin启动子区域的测序结果发现,LTEP-a-2中存在着可能与Kaiso结合的甲基化的Cp G双核苷酸序列和KBS序列。去甲基化试剂5-Aza-CdR能使肺癌细胞系中β-catenin的mRNA表达明显上调。转染Kaiso后,肺癌细胞系中Kaiso的高表达可明显下调β-catenin的mRNA表达。用5-Aza-CdR处理肺癌细胞系后再转染Kaiso,细胞系中β-catenin的mRNA表达上调。染色质免疫共沉淀结果显示LTEP-a-2中Kaiso只能够与甲基化的Cp G双核苷酸序列结合而不与KBS序列结合;蛋白质免疫共沉淀显示Kaiso能够与p120ctn结合。结论:肺癌细胞系LTEP-a-2中p120ctn调节β-catenin的转录是通过转录抑制因子Kaiso与β-catenin启动子区域甲基化的Cp G双核苷酸序列而实现的。

Objective: To explore the mechanism of p120-catenin regulate β-catenin expression in lung cancer cells. Methods: Observed the β-catenin promoter region in LTE lung cancer cell line has Kaiso binding sites sequences. Results: Confirmed that methylated Cp G-dinucleotides sequences combined with Kaiso and the Kaiso binding sites sequence did not using bisulfite sequencing PCR and Chromatin immunoprecipitation. The capacity of Kaiso combined with p120-catenin isoforms was confirmed by immunoprecipitation. Conclusion: Kaiso plays important role in p120 ctn regulating β-catenin expression in lung cancer cell line.