A new paradigm for aptamer therapeutic AS1411 action: uptake by macropinocytosis and its stimulation by a nucleolin-dependent mechanism.
A new paradigm for aptamer therapeutic AS1411 action: uptake by macropinocytosis and its stimulation by a nucleolin-dependent mechanism.
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DOI：
10.1158/0008-5472.can-10-0920
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发表时间：
2010-11-01
期刊：
影响因子：
11.2
通讯作者：
Bates PJ
中科院分区：
文献类型：
--
作者：
Reyes-Reyes EM;Teng Y;Bates PJ
AS 1411是一种一流的抗癌药物，目前正在进行II期临床试验。它是一种四链体形成的寡脱氧核苷酸，作为适体与核仁素结合，但其作用机制尚不完全清楚。机制的见解可能会导致临床上有用的标志物AS 1411反应和新的靶向治疗。之前，我们提出了一个模型，其中细胞表面核仁素作为AS 1411的受体，导致癌细胞的选择性摄取。在这里，我们比较了DU 145前列腺癌细胞（对AS 1411敏感）和Hs 27非恶性皮肤成纤维细胞（对AS 1411耐药）中荧光团标记的AS 1411（FL-AS 1411）的摄取。FL-AS 1411的摄取在两种细胞类型中均通过胞吞作用发生，并且比无活性的非四链体寡核苷酸更有效。出乎意料的是，与Hs 27细胞相比，癌细胞中FL-AS 1411的摄取较低。然而，摄取的机制是不同的，发生在癌细胞中的巨胞饮，但在Hs 27细胞中的非巨胞饮途径。此外，用AS 1411处理各种癌细胞引起巨胞饮过度刺激，引起其自身摄取增加，而非恶性细胞未观察到刺激。核仁素不是DU 145细胞中FL-AS 1411初始摄取所必需的，但对于诱导的巨胞饮和随后的FL-AS 1411摄取是必需的。我们的研究结果与以前的机制模型不一致，但证实核仁素在介导AS 1411效应中起作用。这些数据表明，一个新的模型AS 1411的行动，以及一个新的作用核仁素刺激巨胞饮，一个过程中的药物输送的潜在应用。
AS1411 is a first-in-class anticancer agent, currently in Phase II clinical trials. It is a quadruplex-forming oligodeoxynucleotide that binds to nucleolin as an aptamer, but its mechanism of action is not completely understood. Mechanistic insights could lead to clinically useful markers for AS1411 response and to novel targeted therapies. Previously, we proposed a model where cell surface nucleolin serves as the receptor for AS1411, leading to selective uptake in cancer cells. Here, we compare uptake of fluorophore-labeled AS1411 (FL-AS1411) in DU145 prostate cancer cells (sensitive to AS1411) and Hs27 non-malignant skin fibroblasts (resistant to AS1411). Uptake of FL-AS1411 occurred by endocytosis in both cell types and was much more efficient than an inactive, non-quadruplex oligonucleotide. Unexpectedly, uptake of FL-AS1411 was lower in cancer cells compared to Hs27 cells. However, the mechanism of uptake was different, occurring by macropinocytosis in cancer cells, but by a non-macropinocytic pathway in Hs27 cells. Additionally, treatment of various cancer cells with AS1411 caused hyperstimulation of macropinocytosis, provoking an increase in its own uptake, whereas no stimulation was observed for non-malignant cells. Nucleolin was not required for initial FL-AS1411 uptake in DU145 cells, but was necessary for induced macropinocytosis and FL-AS1411 uptake at later times. Our results are inconsistent with the previous mechanistic model, but confirm that nucleolin plays a role in mediating AS1411 effects. The data suggest a new model for AS1411 action, as well as a new role for nucleolin in stimulating macropinocytosis, a process with potential applications in drug delivery.