Mechanism and Regulation of DNA Repair Team, UFIP, UMR 6286 CNRS, University of Nantes, F-44000 Nantes, France.
Genome Stability Laboratory, CHU de Québec Research Center, HDQ Pavilion, Oncology Division, 9 McMahon, Québec City, QC G1R 3S3, Canada.
Molecules. 2021 Sep 8;26(18):5460. doi: 10.3390/molecules26185460.
RAD51 is the central protein in DNA repair by homologous recombination (HR), involved in several steps of this process. It is shown that overexpression of the RAD51 protein is correlated with increased survival of cancer cells to cancer treatments. For the past decade, RAD51 overexpression-mediated resistance has justified the development of targeted inhibitors. One of the first molecules described to inhibit RAD51 was the 4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid (DIDS) molecule. This small molecule is effective in inhibiting different functions of RAD51, however its mode of action and the chemical functions involved in this inhibition have not been identified. In this work, we used several commercial molecules derived from DIDS to characterize the structural determinants involved in modulating the activity of RAD51. By combining biochemical and biophysical approaches, we have shown that DIDS and two analogs were able to inhibit the binding of RAD51 to ssDNA and prevent the formation of D-loop by RAD51. Both isothiocyanate substituents of DIDS appear to be essential in the inhibition of RAD51. These results open the way to the synthesis of new molecules derived from DIDS that should be greater modulators of RAD51 and more efficient for HR inhibition.
RAD51 是同源重组（HR）DNA 修复的核心蛋白，参与该过程的多个步骤。研究表明，RAD51 蛋白的过表达与癌细胞对癌症治疗的存活率增加有关。在过去的十年中，RAD51 过表达介导的耐药性促使开发了靶向抑制剂。第一个被描述为抑制 RAD51 的分子是 4,4'-二异硫氰酸根合二苯乙烯-2,2'-二磺酸（DIDS）分子。这种小分子能有效抑制 RAD51 的不同功能，但它的作用方式以及涉及这种抑制的化学功能尚未确定。在这项工作中，我们使用了几种源自 DIDS 的商业分子来表征调节 RAD51 活性的结构决定因素。通过结合生化和生物物理方法，我们表明 DIDS 和两种类似物能够抑制 RAD51 与 ssDNA 的结合，并阻止 RAD51 形成 D 环。DIDS 的两个异硫氰酸酯取代基似乎对 RAD51 的抑制都是必不可少的。这些结果为合成源自 DIDS 的新分子开辟了道路，这些新分子应该是 RAD51 的更好调节剂，并且对 HR 抑制更有效。
