5-Ethynyl-2'-deoxyuridine (Synonyms: 5-EdU, EdU, 2'-deoxy-5-Ethynyluridine)

5-ethynyl-2′-deoxyuridine (EdU), as a thymidine analoghas, a terminal alkyne group replacing a methyl group at the 5 position of the pyrimidine ring and can be readily incorporated into DNA during synthesis[1]. EdU is a inhibitor of the cell growth of human breast cancer cells (MCF-7 and MDA-MP-231) with the IC₅₀ of 0.4 μM for MCF-7 cells and 4.4 μM for MDA-MB-231 cells^[2].

In vitro, 10 μMEdU induced gamma-H2AX foci for 51D1 and KO40 in CHO cells for DNA damage responses^[3]. In vitro experiment it shown that A549 cells were treated with 20 μM EdU for 6 h increased the level of expression of γH2AX and ATM-S1981P by 88% and 116%, respectively^[4].

In vivo efficacy test it shown that femalJKe mice were administrated 10, 20, 50, 100 or 200 mg/kg EdU intraperitoneally, there is an increase in the number of EdU positive cells in the DG slightlyin a dose-dependent manner^[5]. In vivo, few EdU-positive cells were observed in Wistar and GK rats at a dose of 5 mg/kg and 25 mg/kg EdU intraperitoneally. Prominent EdU-positive cells were observed in Wistar and GK rats at a dose of 100 mg/kg and 200 mg/kg, respectively^[6]. In vivo, use of 5-Ethynyl-2'-deoxyuridine (EdU) incorporation to in vivo monitor T lymphocyte proliferation by flow cytometry with an adoptive transfer model. The result shown that the percentage of EdU-positive cells increased in a dose-dependent manner, and the saturated dose of EdU was 20mg/kg. Intraperitoneal and intravenous injection had no differences in lymphocyte proliferation detection with EdU in vivo^[7].

References:

[1] Kaiser CL, et al. 5-Ethynyl-2'-deoxyuridine labeling detects proliferating cells in the regenerating avian cochlea. Laryngoscope. 2009 Sep;119(9):1770-5.

[2] Meneni S, et al. (2007) 5-Alkynyl-2′-deoxyuridines: chromatography-free synthesis and cytotoxicity evaluation against human breast cancer cells. Bioorg Med Chem 15: 3082–3088.

[3] Haskins JS, et al. Evaluating the Genotoxic and Cytotoxic Effects of Thymidine Analogs, 5-Ethynyl-2'-Deoxyuridine and 5-Bromo-2'-Deoxyurdine to Mammalian Cells. Int J Mol Sci. 2020 Sep 10;21(18):6631.

[4] Zhao H, et al. DNA damage signaling, impairment of cell cycle progression, and apoptosis triggered by 5-ethynyl-2'-deoxyuridine incorporated into DNA. Cytometry A. 2013 Nov;83(11):979-88.

[5] Zeng C, et al. Evaluation of 5-ethynyl-2'-deoxyuridine staining as a sensitive and reliable method for studying cell proliferation in the adult nervous system. Brain Res. 2010 Mar 10;1319:21-32.

[6] Guo J, Li D, et al. Detecting DNA synthesis of neointimal formation after catheter balloon injury in GK and in Wistar rats: using 5-ethynyl-2'-deoxyuridine. Cardiovasc Diabetol. 2012 Dec 13;11:150.

[7] Sun X, Zhang C, et al. Flow cytometric analysis of T lymphocyte proliferation in vivo by EdU incorporation. Int Immunopharmacol. 2016 Dec;41:56-65.