DIDS, a chemical compound that inhibits RAD51-mediated homologous pairing and strand exchange

Abstract

RAD51, an essential eukaryotic DNA recombinase, promotes homologous pairing and strand exchange during homologous recombination and the recombinational repair of double strand breaks. Mutations that up- or down-regulate RAD51 gene expression have been identified in several tumors, suggesting that inappropriate expression of the RAD51 activity may cause tumorigenesis. To identify chemical compounds that affect the RAD51 activity, in the present study, we performed the RAD51-mediated strand exchange assay in the presence of 185 chemical compounds. We found that 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS) efficiently inhibited the RAD51-mediated strand exchange. DIDS also inhibited the RAD51-mediated homologous pairing in the absence of RPA. A surface plasmon resonance analysis revealed that DIDS directly binds to RAD51. A gel mobility shift assay showed that DIDS significantly inhibited the DNA-binding activity of RAD51. Therefore, DIDS may bind near the DNA binding site(s) of RAD51 and compete with DNA for RAD51 binding.

Targeting RAD51 phosphotyrosine-315 to prevent unfaithful recombination repair in BCR-ABL1 leukemia

“…5,45 Because up-regulation of RAD51 recombinase may cause genomic instability, several approaches have been developed to inhibit/control its activity, for example, protein aptamer derived from BRC4 motif of BRCA2 to inhibit RAD51 filament formation and DNA aptamer and a chemical compound that inhibit RAD51-dependent pairing and strand exchange. [46][47][48] However, these strategies will also target RAD51-mediated HomoRR in normal cells, which may exert a deleterious effect on cell survival and chromosomal stability. 49 Instead, we propose to target the region of RAD51, RAD51(pY315), which is directly phosphorylated by BCR-ABL1 oncogenic kinase, preferentially detected in the nuclei of leukemia, but not normal cells, and involved in HomeoRR.…”

Knockdown of Rad51 expression induces radiation- and chemo-sensitivity in osteosarcoma cells

“…Recently, Lin, Y W et al have reported a variety of drugs that inhibit the expression of Rad51, such as DIDS [16], erlotinib [17], emodin [18], and gefitinib [19]. Therefore, these drugs can be investigated in future studies, particularly to test if their combination can enhance the therapeutic effect against osteosarcoma.…”

Identification and characterization of human Rad51 inhibitors by screening of an existing drug library

“…From now, different assays were adapted for screening Rad51 inhibitors [17,19,20]. To identify chemical compounds that inhibit Rad51 activity, we employed here a different method, which is an electrophoresis-based DNA strand exchange assay as described in Fig.…”

“…Given the involvement of Rad51 in such severe diseases, it represents an important target for anticancer therapy and the development of small molecule inhibitors capable of inhibiting Rad51 activities is warranted. Thence, very recently, few compounds have been identified as inhibitors of Rad51 and the great majority of them have been selected by high-throughput screening from chemical libraries [17][18][19][20]. However, the development of a new drug is a hard and expensive process, including the fact that new drugs have to undergo a challenging approval process by the Food and Drug Administration (FDA) in order to make sure that the drug is safe for consumption.…”