前列腺癌LNCaP细胞L—plastin启动子-1751C／T单核苷酸多态性导致与转录因子NKX3．1结合活性改变

Single nucleotide polymorphism -1751C/T of L- plastin promoter leads to binding ac- tivity of NKX3.1 transcription factor in prostate cancer

目的鉴定与前列腺癌LNCaP细胞肌动蛋白结合蛋白L—plastin启动子-1751C／T单核苷酸多态性位点结合的转录因子，并研究-175lC／T单核苷酸多态性导致与转录因子结合活性的改变。方法应用荧光素酶活性实验和凝胶迁移实验分析是否有转录因子结合于L—plastin启动子的-175lC／T位点。应用生物信息学分析L—plastin启动子-1751位点可能的结合蛋白，并应用凝胶迁移超滞后实验证实。应用Westernblot检测该蛋白在正常前列腺上皮及前列腺癌细胞中的表达水平。结果有一个抑制性转录因子结合于L—plastin启动子的-1751T序列上。生物信息学预测L—plastin启动子-1751位点可能的结合蛋白有5个可能，凝胶迁移超滞后实验证实为NKX3．1。NKX3．1在前列腺癌细胞中过表达，与L—plastin启动子-1751T序列较-1751C序列有更高的亲和力结论L—plastin启动子-1751C／T单核苷酸多态性导致与NKX3．1结合活性改变，可能与前列腺癌发病相关。

Objectives To identify the transcription factor binding to the - 1751C/T single nucleotide pol- ymorphism site of the promoter of L - plastin of prostate cancer cell line LNCaP, and to study the resulted binding ac- tivity changes of the transcription factor. Methods Luciferase reporter assay and electrophoresis motility shift as- say was used to identity if there is transcription factor binding to the - 1751C/T single nucleotide polymorphism site of the promoter of L - plastin. Bioinformatic analysis was conducted to predict the transcription factor binding to the -1751C/T site, and super shift assay was used to confirmed the interaction of the transcription factor and the - 1751C/T site. Western blot was used to detect the expression level of this transcription factor in normal prostate epi- thelial and prostate cancer cell line. Results A suppressive transcription factor was identified binding to the - 1751C/T single nucleotide polymorphism site of the promoter of L - plastin. Bioinformatic analysis predicted 5 possi- ble protein can bind to this site. Super shift assay confirmed that NKX3.1 was the transcription factor binding to - 1751C/T single nucleotide polymorphism site, and NKX3.1 was over- expressed in prostate cancer cell. NKX3.1 has higher binding affinity to - 1751T than to - 1751C. Conclusions The - 1751C/T single nucleotide poly- morphism site of the promoter of L - plastin leads to binding affinity of NKX3.1 changes, and may be related to prostate cancer carcinogenesis.