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目的研究靶向肿瘤细胞高表达核仁素的核酸适配体AS1411与靶标作用的结合模式。方法利用CD光谱评价了退火及末端修饰对AS1411平行及反平行G-四链体(G-4)结构的影响,同时利用肿瘤细胞生长抑制实验评价了退火及末端修饰对AS1411抗肿瘤活性的影响,并通过流式细胞术对末端荧光基团缀合AS1411的靶向肿瘤细胞摄取进行了考察。结果推测G-4结构的端基参与靶蛋白的结合,3’-末端缀合对细胞靶向摄取有较明显的影响,说明AS1411的肿瘤细胞摄取与其抗肿瘤活性有一定程度的关联。结论利用等当量AS1411与其3’-末端缀合物退火形成不对称的反平行G-4,可以更好地保持其与肿瘤细胞的靶向结合及生长抑制活性,说明AS1411的端基是其发挥药效的重要区域。该结果可进一步应用于肿瘤的靶向检测和治疗研究。
Aim To study the binding mode of target nucleic acid aptamer AS1411 that targets highly expressed nucleolin in tumor cells. Methods The effects of annealing and terminal modification on the structures of parallel and anti-parallel G-quadruplexes (G-4) of AS1411 were evaluated by CD spectra. Meanwhile, the effects of annealing and terminal modification on the antitumor activity of AS1411 were evaluated by tumor cell growth inhibition , And targeted tumor cell uptake by terminal fluorophore conjugated AS1411 was examined by flow cytometry. The results suggest that the terminal G-4 structure of the target protein involved in binding, 3’-terminal conjugation of cell-targeted uptake has a more significant impact on the uptake of AS1411 tumor cells and anti-tumor activity to some extent. Conclusion Asymmetric anti-parallel G-4 is formed by annealing the equivalent AS1411 and its 3’-terminal conjugate, which can better maintain its target binding and growth inhibitory activity with tumor cells, indicating that the end group of AS1411 plays its role Important area of efficacy. The results can be further applied to the tumor detection and treatment of targeted research.