OligoY - a new class of oligonucleotide-based therapeutic means

已经开发了一些RNA药物来对抗癌症等多基因疾病。由于早期临床试验的失败或疗效有限，人们对RNAi疗法前景的早期热情迅速减弱。1数十年来，核酸修饰可以影响配对和化学稳定性、构象以及与参与靶标摄取、运输或加工的蛋白质和酶的相互作用，一直是寡核苷酸治疗领域的主要焦点。虽然许多基于RNA的药物正在开发中，但有效的基于RNA的治疗策略仍然存在重大障碍，包括将药物输送到特定部位或组织、非靶点效应和治疗的持久性。RNAi、反义和剪接开关寡核苷酸是仍在筛选中的主要治疗类型。尽管RNAi药物在临床试验中显示出良好的效果，并且已有一些代表性药物获得FDA的批准，但由于其作用方式的原因，本质上存在一些局限性。RNAi和miRNA途径共享共同的蛋白质，如参与miRNA成熟的Ago2。因此，siRNA药物与内源性miRNAs竞争Ago2结合，限制了所有siRNA药物的效率。为了弥补这一点，必须仔细优化RNA药物的浓度，以避免过量的RNA药物饱和RISC机制并抑制正常的miRNA途径。拟议的项目研究了一种新药RNA药物OdonoY的设计，它可以阻断细胞增殖中最基本的机制，DNA复制。DNA复制是从一个DNA模板产生两个完全相同的DNA拷贝的细胞过程。它是细胞分裂中最重要的过程，但它的启动仍然知之甚少。真核生物中的DNA复制利用几个细胞外信号来协调多细胞生物体的专门隔间。寡核苷酸通过与一系列非编码RNA、Y RNA的结合间接作用于复制，在复制起始步骤中特异性地阻断Y RNA与ORC(Origin Replication Complex)的相互作用。寡聚Y是由两条化学修饰的RNA和第三个元件(肽、适配子、抗体、POD)形成的复合体，它们与Y RNA靶标互补，具有细胞选择性。为了测试它们作为药物的应用，它们将首先在几个癌细胞系中进行评估。寡聚Y可能是第一个基于寡核苷酸的药物，它作用于DNA复制机制，绕过了与治疗期间和患者之间的疾病变化相关的所有缺点。

A number of RNA drugs have been developed to combat polygenic diseases such as cancer. The early enthusiasm for the promise of RNAi therapeutics was quickly weakened by the failure or limited efficacy in early clinical trials.1 Decades of studies on modification of nucleic acids which can affect pairing and chemical stability, conformation and interactions with a proteins and enzymes involved in uptake, transport or processing of targets have been the main focus of the oligonucleotide therapeutic field. While many RNA-based drugs are in development, there are still significant barriers to efficient RNA-based treatment strategies including delivery of the drug to a particular site or tissue, off-target effects and longevity of the treatment.RNAi, antisense and splice-switching oligonucleotides are the main class of therapeutic still under screening. RNAi drugs, although being showing promising result in clinical trial and having some representative drugs already FDA approved, are intrinsically presenting some limitations due to their modality of action. The RNAi and miRNA pathway share common proteins, like Ago2, which are involved in miRNA maturation. Hence, siRNA drugs compete with endogenous miRNAs for Ago2 binding, limiting the efficiency of all siRNA drugs. To compensate this, the concentration of the RNA drug must be carefully optimized avoiding an excess that could saturate the RISC machinery and inhibiting the normal miRNA pathway.The proposed project investigates the design of a new drug RNA drug, 'OligoY', which blocks the most essential mechanism in cell proliferation, DNA replication. DNA replication is the cell process of producing two identical copies of DNA from one DNA template. It is the most essential process in cell division but its initiation is still poorly understood. DNA replication in eukaryotes employs several extracellular signals to coordinate the specialized compartment of the multicellular organisms. OligoYs act indirectly on replication through the binding with a family of non-coding RNA, Y RNAs, specifically blocking the interaction of Y RNA with ORC (Origin Replication complex) during the replication initiation step. OligoYs are complexes formed by two strands of chemically modified RNAs, complementary to the Y RNA target, and a third element (peptide, aptamer, antibody, POD) conferring cell-selectivity. To test their application as drug, they will be initially evaluated in several cancer cell lines. OligoYs are potentially the first example of an oligonucleotide-based drug that acts on the DNA replication mechanism, bypassing all the drawbacks associated to variations of the disease during treatment and between patients.