G-quadruplex in Translational Regulation and Cancer Therapy

描述(申请人提供)：长期目标是通过同时治疗肝癌和改善肝功能来开发治疗肝癌的新疗法，因为大多数肝癌患者都有肝硬变。一组肝脏富含转录因子是肝脏发育和肝功能的主要调节因子，它们是在肝癌发生过程中下调表达的肿瘤抑制因子。文献报道强烈建议恢复主调节器HNF4？不仅可以治疗肝癌，还可以治疗肝纤维化。 然而，像许多重要的癌基因和肿瘤抑制因子一样，HNF4？是一种缺乏已知激活配体的转铁蛋白；如何调节“不可用药”的转铁蛋白来治疗癌症是一个巨大的挑战。已经开发出一种化学物质，通过稳定基因启动子中的一种特殊的核酸结构--G-四链(G4)，来沉默“不可抑制的”癌基因。然而，G4稳定剂缺乏对正常细胞的选择性是开发G4稳定剂作为新型抗癌药物的瓶颈。我们的初步数据有力地表明，5‘非翻译区(UTR)中的G4基序在抑制HNF4蛋白翻译中起着关键作用。和某些富含肝脏的基本转铁蛋白。这项建议的目的是阐明5‘非编码区G4基序在富含肝脏的转录因子的翻译调控和癌症治疗中的重要性。中心假说是，这些主调控子5‘UTR中的G4基序在抑制其蛋白表达方面发挥了关键作用。因此，我们可以使用小分子或G4DNA寡核苷酸在5‘非编码区内破坏G4的稳定或竞争性地抑制G4相互作用的蛋白，从而增加这些主调控子的蛋白表达。这将是治疗肝癌并同时改善肝功能的一种令人兴奋的创新方法。这一中心假设将在3年内得到检验。 明确的目标。目的1探讨其5‘端非编码区抑制HNF4？1蛋白表达的机制。工作假说是，在5‘非编码区内形成G4基序对于抑制蛋白质表达是必不可少的。目的研究人HNF1？、HNF3？、C/EBP？、C/EBP？、HDAC3、NCOR1和P53基因5‘非编码区G4基序在蛋白表达调控中的作用。工作假说是，5‘非编码区内的G4基序在抑制这些TF的蛋白表达方面是必不可少的。目的3研究G4相互作用的化学物质和上述8种人TF中5‘非编码区的G4寡核苷酸对这些TF蛋白表达的影响。工作假设是TMPYP4、多胺和原卟啉IX抑制，而某些G4DNA寡核苷酸增加这些TF在肝癌/肝细胞中的蛋白表达。这项研究具有很高的新颖性，因为它是第一次解决一个重要的核酸结构，G4在调节一组基本的肝脏富含TF的蛋白质表达中的重要性。这项研究具有重要的意义，因为这项研究的结果不仅将提供重要的新知识，而且将极大地帮助合理设计G4相互作用的抗癌药物，并有助于开发一种范式转换方法，以协调靶向原本无法用药的基本的富含肝脏的TF，以同时治疗肝癌和改善肝功能。

DESCRIPTION (provided by applicant): The long term goal is to develop novel therapy for liver cancer through simultaneously treating liver cancer and improving liver function, because most liver cancer patients have liver cirrhosis. A group of liver-enriched transcription factors (TFs) are master regulators of liver development and liver function, and they are tumor- suppressors down-regulated during liver carcinogenesis. Literature reports strongly suggest that restoration of the master regulator HNF4? can treat not only liver cancer, but also liver fibrosis. However, like many important oncogenes and tumor-suppressors, HNF4? is a TF that lacks known activating ligand; how to modulate "undruggable" TFs to treat cancer is a huge challenge. Chemicals have been developed to silence "undruggable" oncogenes via stabilizing a special nucleic acid structure, G-quadruplex (G4) in gene promoter. However, the lack of selectivity of G4-stabilizing chemicals toward normal cells is a bottleneck in developing G4-stabilizing chemicals as novel anticancer drugs. Our preliminary data strongly suggest that G4 motif within 5' untranslated region (UTR) is critical in suppressing protein translation of HNF4? and certain liver- enriched essential TFs. The objective of this proposal is to elucidate the importance of G4 motif within 5' UTR in translational regulation of liver-enriched TFs and cancer therapy. The central hypothesis is that G4 motifs in 5' UTR of these master regulators play a key role in suppressing their protein expression. Thus, we can increase protein expression of these master regulators using small molecules or G4 DNA oligos to destabilize G4 within 5' UTR or competitively inhibit G4-interacting proteins. This will be an exciting innovative approach to trea liver cancer and improve liver function simultaneously. This central hypothesis will be tested in 3 specific aims. Aim 1 will determine mechanism of suppression of protein expression of HNF4?1 by its 5' UTR. The working hypothesis is that formation of G4 motif within 5' UTR is essential in inhibiting protein expression. Aim 2 will determine role of G4 motif within 5' UTR of human HNF1?, HNF3?, C/EBP?, C/EBP?, HDAC3, NCOR1, and p53 in regulating protein expression. The working hypothesis is that G4 motif within 5' UTR is essential in suppressing protein expression of these TFs. Aim 3 will determine effects of G4-interacting chemicals and G4 oligos from 5' UTR of above 8 human TFs on protein expression of these TFs. The working hypothesis is that TMPYP4, polyamines, and protoporphyrin IX inhibits, whereas certain G4 DNA oligos increase protein expression of these TFs in hepatoma/hepatocytes. This study is highly novel, because it is the first to address the importance of an important nucleic acid structure, G4 in regulating the protein expression of a group of essential liver-enriched TFs. This study is highly significant, because results from this study will not only provide important novel knowledge, but also greatly aid the rational design of G4- interacting anticancer drugs, and help to develop a paradigm-shift approach to coordinately target otherwise "undruggable" essential liver-enriched TFs to simultaneously treat liver cancer and improve liver function.