Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
College of New Energy and Materials, China University of Petroleum (Beijing), Beijing 102249, China.
ACS Appl Bio Mater. 2022 Jul 18;5(7):3461-3468. doi: 10.1021/acsabm.2c00389. Epub 2022 Jul 6.
As a kind of recognition molecule, aptamers can be inserted into some regulatory sequences for the smart response of their targets. However, the molecular engineering might lead to the change of the binding affinity. Here, we present a stable aptamer ZAJ-2c and an environmentally sensitive aptamer ZAJ-2d optimized from an original cell-binding aptamer ZAJ-2, and the molecular target was further identified as CD49c on the cell membrane. ZAJ-2c was characterized with high binding ability independent of the presence of divalent cations at a temperature range from 4 to 37 °C, showing promise for measuring the expression of CD49c on cancer cells. Moreover, ZAJ-2d had a nanomolar binding affinity in the binding buffer at 4 °C, the same as ZAJ-2c, but lost the binding ability in a PBS buffer supplemented with 5 mM EDTA at 37 °C. This aptamer variant proved to selectively capture and release the CD49c positive cells by simply adjusting the temperatures and divalent cations. This set of aptamers might provide a toolbox for monitoring and operating of a wide range of cancer cells with CD49c expression on the surface, which will be helpful for the studying the heterogeneity of rare cells.
作为一种识别分子，适体可以插入到一些调控序列中，从而对其靶标进行智能响应。然而，分子工程可能会导致结合亲和力的改变。在这里，我们从原始的细胞结合适体 ZAJ-2 中优化得到了稳定的适体 ZAJ-2c 和对环境敏感的适体 ZAJ-2d，并且进一步鉴定出其细胞膜上的分子靶标为 CD49c。ZAJ-2c 具有在 4 至 37°C 的温度范围内，无论是否存在二价阳离子，都具有高结合能力的特点，有望用于测量癌细胞上 CD49c 的表达。此外，ZAJ-2d 在 4°C 的结合缓冲液中具有纳摩尔级的结合亲和力，与 ZAJ-2c 相同，但在 37°C 的含 5mM EDTA 的 PBS 缓冲液中失去了结合能力。这种适体变体通过简单地调整温度和二价阳离子，被证明可以选择性地捕获和释放 CD49c 阳性细胞。这组适体可能为监测和操作具有表面 CD49c 表达的广泛范围的癌细胞提供了一个工具包，这将有助于研究稀有细胞的异质性。
