RNAi沉默PSMA基因对前列腺癌LNCaP细胞生物学行为的影响

目的：构建LNCaP细胞PSMA基因的shRNA真核表达载体，探讨其对LNCaP细胞中PSMA基因表达的干扰作用。方法:针对PSMA mRNA序列设计合成3对编码shRNA的寡核苷酸链，退火形成双链，连接入含有BamHⅠ和HindⅢ酶切位点的pSilencer 2.1-U6-neo真核表达载体，双酶切及测序鉴定。使用脂质体转染的方法将重组质粒导入LNCaP细胞，G418筛选后RT-PCR、Western blotting检测其对PSMA基因干扰作用，并观察对LNCaP细胞生物学行为的影响。结果:经酶切及测序鉴定，成功构建shRNA真核表达载体p-shRNA1,2,3转染LNCaP后，对细胞PSMA mRNA表达抑制率分别为33.15%、9.26%、41.97%，Western blotting结果显示对PSMA蛋白表达的抑制率分别为26.26%、6.47%、40.69%。选择抑制效率较高的p-shRNA3进行体外生长及侵袭力实验，发现干扰后对LNCaP细胞侵袭力增强, 但是对细胞生长影响不大。结论:成功构建了人PSMA基因的RNAi的真核表达载体，并在LNCaP细胞中有效地发挥了对PSMA基因表达的干扰作用，初步发现PSMA在前列腺癌的侵袭中起负向调节作用，为进一步研究PSMA的生物学功能，探索前列腺癌的发病机制奠定一定的实验基础。

Silencing of PSMA by RNAi influences biological behavior of prostate cancer cell line LNCaP

AIM:To study the blocking effect of shRNA on the expression of PSMA gene in LNCaP cell line by using shRNA eukaryotic expression vector.METHODS:Three pairs of DNA templates coding shRNA,synthesized against PSMA and cloned into the vector pSilencer 2.1-U6-neo,which was named pSilencer 2.1-U6-neo-shRNA,were identified by restriction endonuclease digestion analysis and DNA sequencing.LNCaP cells were then transfected with these three pSilencer 2.1-U6-neo-shRNAs and the negative control pSilencer 2.1-U6-neo-NC.After G418 selection,the cells were selected and the interfering effect was detected by RT-PCR and Western blotting.The biological behaviours of the transfected LNCaP cells were also tested.RESULTS:Restriction endonuclease digestion analysis and DNA sequencing results all showed that the 3 target segments were cloned into pSilencer 2.1-U6-neo vector respectively.After transfected into LNCaP cells,the inhibitory ratio of PSMA mRNA was 33.15%,9.26% and 41.97% respectively,and that of PSMA protein was 26.26%,6.47%,40.69% respectively.The p-shRNA3 was chosen to test the cell growth and its invasive power in vitro.The results showed that after interfering,the invasiveness of LNCaP cells were enhanced.CONCLUSION:The vector-based shRNA on PSMA gene effectively knocks down the PSMA gene expression.The successful construction of PSMA shRNA makes it possible for further study of the interaction between PSMA and prostate cancer.