Targeted and directed degradation of oncogenic MYC mRNA with non-enzymatic peptide nucleic acid degraders (degPNAs)

使用非酶肽核酸降解剂 (degPNA) 靶向定向降解致癌 MYC mRNA

• 批准号: EP/X024571/1
• 负责人: Bengt Herbert Gless
• 金额: $ 24.26万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FX024571%2F1
• 关键词: Targeted; directed; degradation; oncogenic; MYC

The MYC oncogene is deregulated in more than 50% of human cancers. However, no clinical treatment is available to date due to the "undruggable" nature of the MYC protein towards small molecule inhibitors. A promising alternative represents the interference with its translation on the mRNA level through the use of antisense oligonucleotides (ASOs). ASOs are short nucleic acids with antisense to the targeted mRNA that induce enzymatic degradation or sterically block translation or splicing. Previous ASOs targeting MYC have shown initial promising clinical results but eventually failed. To overcome the shortcomings of past ASO-based strategies, this project proposes the development and application of peptide nucleic acids-based degraders (degPNAs) of the MYC mRNA utilising a chemical degradation mechanism. The degPNAs degrade the target mRNA upon hydridisation through attached degrader base handles on the peptide backbone, which induce base-mediated cleavage of the phosphodiester bond. This proposal describes the structure-based design and synthesis of MYC mRNA-targeting degPNAs and their optimisation towards efficiency RNA degradation. Further, the conjugation to cell-penetrating peptides (CPPs) is described followed by fluorophore labeling and microscopy to evaluate cell uptake. Finally, in vitro MYC targeting in several cancer cell lines is investigated through RNA and protein quantification as well as global transcriptomics. In conclusion, the proposed degPNAs combine the advantages of charge-neutral ASOs with the flexible design and catalytic mode of action of enzyme-recruiting ASOs, which offers a novel approach for targeted RNA degradation and could pave the way towards a general chemical gene silencer platform.

MYC致癌基因在超过50%的人类癌症中不受控制。然而，由于MYC蛋白对小分子抑制剂的“不可药”性质，迄今为止尚无临床治疗方法。一种有希望的替代方法是通过使用反义寡核苷酸（ASOs）在mRNA水平上干扰其翻译。ASOs是对目标mRNA具有反义的短核酸，可诱导酶降解或空间阻断翻译或剪接。先前针对MYC的ASOs最初显示出有希望的临床结果，但最终失败了。为了克服过去基于aso的策略的缺点，本项目提出利用化学降解机制开发和应用基于肽核酸的MYC mRNA降解物（degPNAs）。降解rna通过肽主链上附着的降解物碱基柄在水化后降解目标mRNA，从而诱导碱基介导的磷酸二酯键的裂解。本提案描述了基于结构的MYC mrna靶向degPNAs的设计和合成及其对RNA降解效率的优化。此外，结合细胞穿透肽（CPPs）描述了随后的荧光团标记和显微镜来评估细胞摄取。最后，通过RNA和蛋白质定量以及全局转录组学研究了MYC在几种癌细胞系中的体外靶向作用。总之，所提出的degPNAs结合了电荷中性ASOs的优点以及酶募集ASOs的灵活设计和催化作用模式，为靶向RNA降解提供了一种新的方法，并为通用化学基因沉默平台铺平了道路。