Abstract

Guanine-rich oligonucleotide (GRO) can be developed as an effective anticancer agent owing to its high selectivity, affinity and antiproliferative activity in cancer cells. In this study, to increase the potency of GRO29A, a 29-mer GRO aptamer against nucleolin, an overexpressed protein in cancer cells, GRO29A was incorporated into three or six pods of polypod-like structured DNA (polypodna), tripodna or hexapodna, respectively. The polypod-like structured GROs, tri-G3, consisting of one tripodna and three GRO29A, or hexa-G1, hexa-G3 or hexa-G6, each of which comprises one hexapodna and one, three or six GRO29A, respectively, were designed. Tri-G3, hexa-G1 and hexa-G3 were prepared in high yield, except for hexa-G6. Polypod-like structured GROs had quadruplex structures under physiological salt conditions, and degraded at a slower rate in buffer containing serum. Cellular interaction experiments using fluorescently labelled DNA samples showed that the uptake of hexa-G3 by nucleolin-positive MCF-7 cells was more than 2-fold higher than GRO29A, and the interaction was increasingly dependent on the number of GRO29A in the structures. Hexa-G3 inhibited the proliferation of MCF-7 cells in more than 40%, but not of CHO cells. These results indicate that polypod-like structured GROs are useful DNA aptamers with high selectivity and cytotoxicity against nucleolin-positive cancer cells.

 抽象的

富含鸟嘌呤的寡核苷酸（GRO）由于其在癌细胞中具有高选择性、亲和力和抗增殖活性，可以开发为有效的抗癌剂。在这项研究中，为了提高 GRO29A（一种 29 聚体 GRO 适体）对抗核仁素（癌细胞中过度表达的蛋白质）的效力，将 GRO29A 分别掺入三个或六个多足类结构 DNA（多足体）、三足体或六足体中。设计了多足类结构的GRO，tri-G3，由一个三足体和三个GRO29A组成，或hexa-G1，hexa-G3或hexa-G6，每个分别包含一个六足体和一个、三个或六个GRO29A。 。除 hexa-G6 外，Tri-G3、hexa-G1 和 hexa-G3 均以高产率制备。多足类结构的GRO在生理盐条件下具有四链体结构，并且在含有血清的缓冲液中以较慢的速率降解。使用荧光标记的 DNA 样品进行的细胞相互作用实验表明，核仁素阳性 MCF-7 细胞对 hexa-G3 的摄取比 GRO29A 高 2 倍以上，并且相互作用越来越依赖于结构中 GRO29A 的数量。 Hexa-G3 抑制 MCF-7 细胞增殖超过 40%，但不抑制 CHO 细胞增殖。这些结果表明，类多足结构的GRO是有用的DNA适体，对核仁素阳性癌细胞具有高选择性和细胞毒性。