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目的同PIWI蛋白结合的RNAs(piRNAs)是一类新发现的非编码小RNA,其可抑制转座子并维持基因组的稳定性。肿瘤组织中可以检测到PIWI和piRNAs的表达,两者表达水平的变化可提示预后。总结PIWI/piRNA下游通路蛋白EXD1和CG9754抑制转座子活化、激活转座子高甲基化与促进转录沉默的作用机制。方法采用PubMed和CNKI期刊全文数据库检索系统,检索2003-01-01-2016-11-30相关文献,以“肿瘤、PIWI、piRNA、通路蛋白、转座子和转录沉默”为关键词检索英文文献420条,中文文献100条。纳入标准:PIWI/piRNA的生物学作用与肿瘤的关系;PIWI/piRNA通路蛋白的作用机制;PIWI/piRNA通路蛋白与转座子和转录沉默的关系,根据纳入标准,符合分析的文献40篇。结果 piRNA是一类新发现的非编码小RNA,PIWI和piRNA的表达水平与肿瘤类型以及肿瘤分期密切相关。Exonuclease domain-containing 1(EXD1)是MIWI2piRNA生物源性基因TDRD12的组成部分。转座子对基因有调节作用。EXD1作为piRNA的通路蛋白,可以辅助piRNA抑制转座的发生。缺少EXD1会引起转座子的活化和反转录转座子的增多。CG9754是转座子抑制和转录沉默过程中重要的piRNA的通路蛋白。CG9754同RNA或DNA的结合可以引起有效的转录沉默。结论 PIWI和piRNA表达水平与肿瘤类型以及分期密切相关,PIWI/piRNA通路蛋白和转座子的关系或许可以解释肿瘤细胞侵袭和转移的能力。PIWI、piRNA、EXD1和CG9754能为靶向治疗提供更多可能性。
The purpose RNAi (piRNAs) that bind to PIWI proteins are a newly discovered class of non-coding small RNAs that inhibit transposons and maintain genome stability. The expression of PIWI and piRNAs can be detected in tumor tissue, and the change of the expression level of both can predict the prognosis. The mechanism of PIWI / piRNA downstream pathway proteins EXD1 and CG9754 inhibiting transposon activation and activating transposon hypermethylation and promoting transcriptional silencing was summarized. Methods PubMed and CNKI journal full-text database retrieval system was used to search the related literature of 2003-01-01-2016-11-30 and the key words of “tumor, PIWI, piRNA, pathway protein, transposon and transcriptional silencing” were searched 420 English articles and 100 Chinese articles. The inclusion criteria: the relationship between the biological effects of PIWI / piRNA and tumor; the mechanism of action of PIWI / piRNA pathway protein; the relationship between PIWI / piRNA pathway protein and transposon and transcriptional silencing, according to inclusion criteria, 40 articles were analyzed. Results piRNA was a newly discovered small non-coding RNA. The expression levels of PIWI and piRNA were closely related to tumor type and tumor stage. Exonuclease domain-containing 1 (EXD1) is part of the TDRD12, a biologically-derived MIWI2piRNA gene. Transposons have a regulatory role on the gene. EXD1 as a piRNA pathway protein, can help piRNA suppress transposition. Lack of EXD1 causes transposon activation and increased retrotransposon turnover. CG9754 is an important piRNA pathway protein in transposon suppression and transcriptional silencing. The binding of CG9754 to RNA or DNA can elicit efficient transcriptional silencing. Conclusions The expression of PIWI and piRNA is closely related to tumor type and stage. The relationship between PIWI / piRNA pathway protein and transposon may explain the ability of tumor cells to invasion and metastasis. PIWI, piRNA, EXD1 and CG9754 provide more possibilities for targeted therapies.