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Honda M, Razzaghi M, Gaur P, Malacaria E, Marozzi G, Biagi LD, Aiello FA, Paintsil EA, Stanfield AJ, Deppe BJ, Gakhar L, Schnicker NJ, Ashley Spies M, Pichierri P, Spies M. A double-ring of human RAD52 remodels replication forks restricting fork reversal. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.14.566657. [PMID: 38014173 PMCID: PMC10680749 DOI: 10.1101/2023.11.14.566657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Human RAD52 1,2 is a multifunctional DNA repair protein involved in several cellular events that support genome stability including protection of stalled DNA replication forks from excessive degradation 3-7 . In its gatekeeper role, RAD52 binds to and stabilizes stalled replication forks during replication stress protecting them from reversal by SMARCAL1 5 . The structural and molecular mechanism of the RAD52-mediated fork protection remains elusive. Here, using P1 nuclease sensitivity, biochemical and single-molecule analyses we show that RAD52 dynamically remodels replication forks through its strand exchange activity. The presence of the ssDNA binding protein RPA at the fork modulates the kinetics of the strand exchange without impeding the reaction outcome. Mass photometry and single-particle cryo-electron microscopy show that the replication fork promotes a unique nucleoprotein structure containing head-to-head arrangement of two undecameric RAD52 rings with an extended positively charged surface that accommodates all three arms of the replication fork. We propose that the formation and continuity of this surface is important for the strand exchange reaction and for competition with SMARCAL1. One Sentence Summary Using cryo-EM, biochemical and single-molecule approaches we show that the structure of stalled DNA replication fork promotes a unique two-ring organization of human RAD52 protein which remodels the fork via DNA strand exchange.
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Myers SH, Poppi L, Rinaldi F, Veronesi M, Ciamarone A, Previtali V, Bagnolini G, Schipani F, Ortega Martínez JA, Girotto S, Di Stefano G, Farabegoli F, Walsh N, De Franco F, Roberti M, Cavalli A. An 19F NMR fragment-based approach for the discovery and development of BRCA2-RAD51 inhibitors to pursuit synthetic lethality in combination with PARP inhibition in pancreatic cancer. Eur J Med Chem 2024; 265:116114. [PMID: 38194775 DOI: 10.1016/j.ejmech.2023.116114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/29/2023] [Accepted: 12/30/2023] [Indexed: 01/11/2024]
Abstract
The BRCA2-RAD51 interaction remains an intriguing target for cancer drug discovery due to its vital role in DNA damage repair mechanisms, which cancer cells become particularly reliant on. Moreover, RAD51 has many synthetically lethal partners, including PARP1-2, which can be exploited to induce synthetic lethality in cancer. In this study, we established a 19F-NMR-fragment based approach to identify RAD51 binders, leading to two initial hits. A subsequent SAR program identified 46 as a low micromolar inhibitor of the BRCA2-RAD51 interaction. 46 was tested in different pancreatic cancer cell lines, to evaluate its ability to inhibit the homologous recombination DNA repair pathway, mediated by BRCA2-RAD51 and trigger synthetic lethality in combination with the PARP inhibitor talazoparib, through the induction of apoptosis. Moreover, we further analyzed the 46/talazoparib combination in 3D pancreatic cancer models. Overall, 46 showed its potential as a tool to evaluate the RAD51/PARP1-2 synthetic lethality mechanism, along with providing a prospect for further inhibitors development.
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Affiliation(s)
- Samuel H Myers
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, 16163, Genoa, Italy
| | - Laura Poppi
- Department of Pharmacy and Biotechnology, University of Bologna, 40126, Bologna, Italy
| | - Francesco Rinaldi
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, 16163, Genoa, Italy; Department of Pharmacy and Biotechnology, University of Bologna, 40126, Bologna, Italy
| | - Marina Veronesi
- Structural Biophysics Facility, Istituto Italiano di Tecnologia, 16163, Genoa, Italy; D3 PharmaChemistry, Istituto Italiano di Tecnologia, 16163, Genoa, Italy
| | - Andrea Ciamarone
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, 16163, Genoa, Italy
| | - Viola Previtali
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, 16163, Genoa, Italy
| | - Greta Bagnolini
- Department of Pharmacy and Biotechnology, University of Bologna, 40126, Bologna, Italy
| | - Fabrizio Schipani
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, 16163, Genoa, Italy
| | | | - Stefania Girotto
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, 16163, Genoa, Italy; Structural Biophysics Facility, Istituto Italiano di Tecnologia, 16163, Genoa, Italy
| | - Giuseppina Di Stefano
- Department of Surgical and Medical Sciences, University of Bologna, 40126, Bologna, Italy
| | - Fulvia Farabegoli
- Department of Pharmacy and Biotechnology, University of Bologna, 40126, Bologna, Italy
| | - Naomi Walsh
- School of Biotechnology, Dublin City University, D09 NR58, Dublin, Ireland
| | | | - Marinella Roberti
- Department of Pharmacy and Biotechnology, University of Bologna, 40126, Bologna, Italy.
| | - Andrea Cavalli
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, 16163, Genoa, Italy; Swiss Federal Institute of Technology Lausanne (EPFL), Switzerland
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Rauth S, Ganguly K, Atri P, Parte S, Nimmakayala RK, Varadharaj V, Nallasamy P, Vengoji R, Ogunleye AO, Lakshmanan I, Chirravuri R, Bessho M, Cox JL, Foster JM, Talmon GA, Bessho T, Ganti AK, Batra SK, Ponnusamy MP. Elevated PAF1-RAD52 axis confers chemoresistance to human cancers. Cell Rep 2023; 42:112043. [PMID: 36709426 PMCID: PMC10374878 DOI: 10.1016/j.celrep.2023.112043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 11/11/2022] [Accepted: 01/13/2023] [Indexed: 01/30/2023] Open
Abstract
Cisplatin- and gemcitabine-based chemotherapeutics represent a mainstay of cancer therapy for most solid tumors; however, resistance limits their curative potential. Here, we identify RNA polymerase II-associated factor 1 (PAF1) as a common driver of cisplatin and gemcitabine resistance in human cancers (ovarian, lung, and pancreas). Mechanistically, cisplatin- and gemcitabine-resistant cells show enhanced DNA repair, which is inhibited by PAF1 silencing. We demonstrate an increased interaction of PAF1 with RAD52 in resistant cells. Targeting the PAF1 and RAD52 axis combined with cisplatin or gemcitabine strongly diminishes the survival potential of resistant cells. Overall, this study shows clinical evidence that the expression of PAF1 contributes to chemotherapy resistance and worse clinical outcome for lethal cancers.
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Affiliation(s)
- Sanchita Rauth
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Koelina Ganguly
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Pranita Atri
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Seema Parte
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Rama Krishna Nimmakayala
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Venkatesh Varadharaj
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Palanisamy Nallasamy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Raghupathy Vengoji
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Ayoola O Ogunleye
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Imayavaramban Lakshmanan
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Ramakanth Chirravuri
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Mika Bessho
- Fred and Pamela Buffett Cancer Center, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Jesse L Cox
- Department of Pathology and Microbiology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Jason M Foster
- Department of Surgery, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Geoffrey A Talmon
- Department of Pathology and Microbiology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Tadayoshi Bessho
- Fred and Pamela Buffett Cancer Center, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Apar Kishor Ganti
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA; Division of Oncology-Hematology, Department of Internal Medicine, VA Nebraska Western Iowa Health Care System, University of Nebraska Medical Center, Omaha, NE, USA; Fred and Pamela Buffett Cancer Center, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center at Omaha, Omaha, NE, USA
| | - Surinder K Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA; Fred and Pamela Buffett Cancer Center, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center at Omaha, Omaha, NE, USA.
| | - Moorthy P Ponnusamy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center at Omaha, Omaha, NE, USA; Fred and Pamela Buffett Cancer Center, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center at Omaha, Omaha, NE, USA.
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