title: Small-Molecule Disruption of RAD52 Rings as a Mechanism for Precision Medicine in BRCA-Deficient Cancers.
abstract: Suppression of RAD52 causes synthetic lethality in BRCA-deficient cells. Yet pharmacological inhibition of RAD52, which binds single-strand DNA (ssDNA) and lacks enzymatic activity, has not been demonstrated. Here, we identify the small molecule 6-hydroxy-DL-dopa (6-OH-dopa) as a major allosteric inhibitor of the RAD52 ssDNA binding domain. For example, we find that multiple small molecules bind to and completely transform RAD52 undecamer rings into dimers, which abolishes the ssDNA binding channel observed in crystal structures. 6-OH-Dopa also disrupts RAD52 heptamer and undecamer ring superstructures, and suppresses RAD52 recruitment and recombination activity in cells with negligible effects on other double-strand break repair pathways. Importantly, we show that 6-OH-dopa selectively inhibits the proliferation of BRCA-deficient cancer cells, including those obtained from leukemia patients. Taken together, these data demonstrate small-molecule disruption of RAD52 rings as a promising mechanism for precision medicine in BRCA-deficient cancers.
authors.affiliation: Department of Medical Genetics and Molecular Biochemistry, Fels Institute for Cancer Research, Temple University School of Medicine, Philadelphia, PA 19140, USA.
authors.forename: Gurushankar
authors.initials: G
authors.lastname: Chandramouly
authors.affiliation: Department of Medical Genetics and Molecular Biochemistry, Fels Institute for Cancer Research, Temple University School of Medicine, Philadelphia, PA 19140, USA.
authors.forename: Shane
authors.initials: S
authors.lastname: McDevitt
authors.affiliation: Department of Microbiology and Immunology, Fels Institute for Cancer Research, Temple University School of Medicine, Philadelphia, PA 19140, USA.
authors.forename: Katherine
authors.initials: K
authors.lastname: Sullivan
authors.affiliation: Department of Medical Genetics and Molecular Biochemistry, Fels Institute for Cancer Research, Temple University School of Medicine, Philadelphia, PA 19140, USA.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Kent
authors.affiliation: High-Throughput and Spectroscopy Resource Center, The Rockefeller University, New York, NY 10065, USA.
authors.forename: Antonio
authors.initials: A
authors.lastname: Luz
authors.affiliation: High-Throughput and Spectroscopy Resource Center, The Rockefeller University, New York, NY 10065, USA.
authors.forename: J Fraser
authors.initials: JF
authors.lastname: Glickman
authors.affiliation: Institute for Cancer Research, Fox Chase Cancer Center, Temple Health, Philadelphia, PA 19111, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Andrake
authors.affiliation: Department of Microbiology and Immunology, Fels Institute for Cancer Research, Temple University School of Medicine, Philadelphia, PA 19140, USA.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Skorski
authors.affiliation: Department of Medical Genetics and Molecular Biochemistry, Fels Institute for Cancer Research, Temple University School of Medicine, Philadelphia, PA 19140, USA. Electronic address: richard.pomerantz@temple.edu.
authors.forename: Richard T
authors.initials: RT
authors.lastname: Pomerantz
mesh_terms: D000494:Allosteric Regulation; D017209:Apoptosis / Q000187:drug effects; D019313:BRCA1 Protein / Q000172:deficiency / Q000235:genetics*; D024682:BRCA2 Protein / Q000172:deficiency / Q000235:genetics*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004249:DNA Damage / Q000187:drug effects; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000378:metabolism; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D024202:Electrophoretic Mobility Shift Assay; D006801:Humans; D020128:Inhibitory Concentration 50; D008856:Microscopy, Fluorescence; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D011485:Protein Binding; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D051721:Rad52 DNA Repair and Recombination Protein / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D054852:Small Molecule Libraries / Q000737:chemistry* / Q000378:metabolism / Q000633:toxicity
chemical_list: D019313:BRCA1 Protein; D024682:BRCA2 Protein; D004277:DNA, Single-Stranded; C497194:RAD52 protein, human; D034741:RNA, Small Interfering; D051721:Rad52 DNA Repair and Recombination Protein; D011994:Recombinant Proteins; D054852:Small Molecule Libraries; C001388:6-hydroxydopa; D004295:Dihydroxyphenylalanine
keywords: DNA repair; cancer; cancer therapeutics; genome instability; high-throughput screening; homologous recombination; single-strand annealing; synthetic lethality