启动子G-四链体调控癌基因hnRNP K及其通过i-motif影响下游c-myc转录表达的分子机制研究

hnRNP K is an important protein overexpressed in many cancer cells, and therefore, is a potential antitumor drug target. It is an important transcriptional regulation protein present in the nucleus, which can up-regulate the transcription and expression of c-myc, through its binding with C-rich sequence/i-motif on c-myc gene promoter region. In our recent bioinformatic and in vivo and in vitro studies, we found a G-rich sequence on the upstream promoter of hnRNP K gene, which could form stable G-quadruplex, and down-regulate transcription and overexpression level of hnRNP K. Based on this important finding, we plan to carry out in-depth mechanistic studies for transcriptional regulation of hnRNP K gene by this G-quadruplex. We also plan to study the mechanism for hnRNP K protein to regulate c-myc gene transcription through its binding with c-myc promoter C-rich sequence/i-motif. We will also synthesize and screen selective binding ligands for protein hnRNP K and its gene promoter G-quadruplex as well as c-myc promoter i-motif as probes, providing powerful tools for the above mechanistic studies. This project will provide a new theoretical basis for elucidating transcriptional regulatory network of hnRNP K, and function and significance of i-motif in regulating c-myc gene transcription and expression, as well as discovery of new types of anti-cancer drugs.

hnRNP K蛋白在许多癌细胞中都过表达，是潜在抗癌药物靶标。它还是细胞核中的重要转录调节蛋白，可与癌基因c-myc启动子区域的富C序列/i-motif结合，上调c-myc的转录表达。我们通过生物信息学和体内外实验发现,该蛋白的基因启动子区域存在富G序列，在形成稳定G-四链体后，显著下调hnRNP K转录表达。本项目将在此重要发现基础上，深入研究hnRNP K基因启动子G-四链体对该基因的转录表达调控机制；进一步探讨hnRNP K蛋白通过c-myc基因启动子富C序列/i-motif调控c-myc转录表达的机制；合成筛选hnRNP K及其基因启动子G-四链体和c-myc启动子i-motif的选择性配体，为上述分子机制研究提供有力工具。本项目将为阐明hnRNP K的转录调控网络和i-motif在c-myc转录调控中的作用和意义，也为新型抗癌药物的研究提供依据。

c-Myc和hnRNP K蛋白在许多癌细胞中都过表达，是潜在抗癌药物靶标,还是细胞核中的重要转录调节蛋白。我们通过生物信息学和大量的体内外实验发现,hnRNP K启动子区域存在富G-序列，这些序列在形成稳定的G-四链体后，能够显著下调hnRNP K的转录和表达水平。本项目在此重要发现基础上，深入研究了hnRNP K基因启动子G-四链体对该基因的转录和表达调控机制；进一步研究了hnRNP K蛋白通过c-myc基因启动子富C序列/i-motif调控c-myc转录表达的机制；合成筛选了hnRNP K和c-myc启动子i-motif的选择性配体，为上述分子机制研究提供了有力工具。本项目进一步阐明了hnRNP K的转录调控网络和i-motif在c-myc转录调控中的作用和意义。本课题组主要研究领域是包括i-motif和G-四链体在内的DNA特殊二级结构及其结合蛋白调控基因表达和影响基因功能的机制以及小分子干预的意义。因为化合物合成需要较多人力财力，在化合物筛选中，除了重点针对hnRNP K蛋白和c-myc启动子i-motif外，我们希望充分利用这些化合物多得到一些结果，因而还筛选和发现了一些结合端粒等其它DNA特殊二级结构及其结合蛋白的选择性配体，也进行了深入的机制研究。这些工作都在我们的抗癌研究领域内，都为新型抗癌药物的研究提供了依据和潜在的药物先导化合物。