Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, I-80126 Napoli, Italy.
Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, I-80126 Napoli, Italy; Institute of Biostructures and Bioimages, CNR, Via Mezzocannone 16, I-80134 Napoli, Italy.
Int J Biol Macromol. 2018 Oct 15;118(Pt B):1384-1399. doi: 10.1016/j.ijbiomac.2018.06.137. Epub 2018 Jul 4.
AS1411 is a nucleolin-binding aptamer which attracted great interest as active targeting ligand for the selective delivery of therapeutic agents to tumour cells. In this work we selected three AS1411 derivatives 5'-conjugated with lipophilic tails and studied their properties in view of their application in liposomial formulations and/or lipid coated-nanoparticles for targeted therapies. The conformational behaviour of these AS1411 analogs has been investigated in comparison with the unmodified aptamer by CD, UV, PAGE, SEC-HPLC, DLS and thioflavin T (ThT) fluorescence assays to get insight in their secondary structure and aggregation properties. This study has been performed in pseudo-physiological buffers mimicking the extra- and intracellular environments, and at different concentrations in the μM range, paying special attention to the effects of the lipophilic tail on the overall aptamer conformation. The 5'-lipidated AS1411 derivatives proved to fold into stable, parallel unimolecular G-quadruplex structures, forming large aggregates, mainly micelles, at conc. >10 μM. Preliminary bioscreenings on selected cancer cells showed that these derivatives are less cytotoxic than AS1411, but maintain a similar biological behaviour. This study demonstrated that lipophilic tails dramatically favour the formation of AS1411 aggregates, however not impairing the formation and thermal stability of its peculiar G4 motifs.
AS1411 是一种核仁素结合适体，作为靶向配体用于将治疗剂选择性递送至肿瘤细胞，引起了极大的关注。在这项工作中，我们选择了三个带有亲脂尾巴的 5'-AS1411 衍生物，并研究了它们在脂质体制剂和/或脂质包裹纳米颗粒中的应用特性，以用于靶向治疗。通过 CD、UV、PAGE、SEC-HPLC、DLS 和硫黄素 T（ThT）荧光分析等方法，比较了这些 AS1411 类似物与未修饰适体的构象行为，以深入了解它们的二级结构和聚集特性。这项研究是在模拟细胞内外环境的类生理缓冲液中进行的，并在 μM 范围内的不同浓度下进行，特别关注亲脂尾巴对整体适体构象的影响。5'-脂质化的 AS1411 衍生物被证明能够折叠成稳定的、平行的单分子 G-四链体结构，在浓度>10μM 时形成大的聚集物，主要是胶束。对选定癌细胞的初步生物筛选表明，这些衍生物的细胞毒性比 AS1411 低，但保持相似的生物学行为。这项研究表明，亲脂尾巴极大地促进了 AS1411 聚集物的形成，但不影响其特殊 G4 基序的形成和热稳定性。
