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Ray U, Gopinatha VK, Sharma S, Goyary L, Choudhary B, Mantelingu K, Rangappa KS, Raghavan SC. Identification and characterization of mercaptopyrimidine-based small molecules as inhibitors of nonhomologous DNA end joining. FEBS J 2023; 290:796-820. [PMID: 36048168 DOI: 10.1111/febs.16615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/21/2022] [Accepted: 08/31/2022] [Indexed: 02/04/2023]
Abstract
Mercaptopyrimidine derivatives are heterocyclic compounds with potent biological activities including antiproliferative, antibacterial, and anti-inflammatory properties. The present study describes the synthesis and characterization of several mercaptopyrimidine derivatives through condensation of 5,6-diamino-2-mercaptopyrimidin-4-ol with various heterocyclic and aromatic aldehydes. Previous studies have shown that SCR7, synthesized from 5,6-diamino-2-mercaptopyrimidin-4-ol, induced cytotoxicity by targeting cancer cells by primarily inhibiting DNA Ligase IV involved in nonhomologous end joining, one of the major DNA double-strand break repair pathways. Inhibition of DNA repair pathways is considered as an important strategy for cancer therapy. Due to limitations of SCR7 in terms of IC50 in cancer cells, here we have designed, synthesized, and characterized potent derivatives of SCR7 using 5,6-diamino-2-mercaptopyrimidin-4-ol as the starting material. Several synthesized imine compounds exhibited significant improvement in inhibition of end joining and cytotoxicity up to 27-fold lower concentrations than SCR7. Among these, two compounds, SCR116 and SCR132, showed increased cancer cell death in a Ligase IV-dependent manner. Treatment with the compounds also led to reduction in V(D)J recombination efficiency, cell cycle arrest at G2/M phase, accumulation of double-strand breaks inside cells, and improved anti-cancer potential when combined with γ-radiation and radiomimetic drugs. Thus, we describe novel inhibitors of NHEJ with higher efficacy and potential, which can be developed as cancer therapeutics.
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Affiliation(s)
- Ujjayinee Ray
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Vindya K Gopinatha
- Department of Biochemistry, Indian Institute of Science, Bangalore, India.,Department of Studies in Chemistry, University of Mysore, India
| | - Shivangi Sharma
- Department of Biochemistry, Indian Institute of Science, Bangalore, India.,Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, India
| | - Laijau Goyary
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, India
| | | | - Kanchugarakoppal S Rangappa
- Department of Studies in Chemistry, University of Mysore, India.,Institution of Excellence, Vijnana Bhavana, University of Mysore, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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Ray U, Raghavan SC. Understanding the DNA double-strand break repair and its therapeutic implications. DNA Repair (Amst) 2021; 106:103177. [PMID: 34325086 DOI: 10.1016/j.dnarep.2021.103177] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 06/25/2021] [Accepted: 07/07/2021] [Indexed: 10/20/2022]
Abstract
Repair of DNA double-strand breaks (DSBs) and its regulation are tightly integrated inside cells. Homologous recombination, nonhomologous end joining and microhomology mediated end joining are three major DSB repair pathways in mammalian cells. Targeting proteins associated with these repair pathways using small molecule inhibitors can prove effective in tumors, especially those with deregulated repair. Sensitization of cancer to current age therapy including radio and chemotherapy, using small molecule inhibitors is promising and warrant further development. Although several are under clinical trial, till date no repair inhibitor is approved for commercial use in cancer patients, with the exception of PARP inhibitors targeting single-strand break repair. Based on molecular profiling of repair proteins, better prognostic and therapeutic output can be achieved in patients. In the present review, we highlight the different mechanisms of DSB repair, chromatin dynamics to provide repair accessibility and modulation of inhibitors in association with molecular profiling and current gold standard treatment modalities for cancer.
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Affiliation(s)
- Ujjayinee Ray
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
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Gopalakrishnan V, Sharma S, Ray U, Manjunath M, Lakshmanan D, Vartak SV, Gopinatha VK, Srivastava M, Kempegowda M, Choudhary B, Raghavan SC. SCR7, an inhibitor of NHEJ can sensitize tumor cells to ionization radiation. Mol Carcinog 2021; 60:627-643. [PMID: 34192388 DOI: 10.1002/mc.23329] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 06/01/2021] [Accepted: 06/07/2021] [Indexed: 12/30/2022]
Abstract
Nonhomologous end joining (NHEJ), one of the major DNA double-strand break repair pathways, plays a significant role in cancer cell proliferation and resistance to radio and chemotherapeutic agents. Previously, we had described a small molecule inhibitor, SCR7, which inhibited NHEJ in a DNA Ligase IV dependent manner. Here, we report that SCR7 potentiates the effect of γ-radiation (IR) that induces DNA breaks as intermediates to eradicate cancer cells. Dose fractionation studies revealed that coadministration of SCR7 and IR (0.5 Gy) in mice Dalton's lymphoma (DLA) model led to a significant reduction in mice tumor cell proliferation, which was equivalent to that observed for 2 Gy dose when both solid and liquid tumor models were used. Besides, co-treatment with SCR7 and 1 Gy of IR further improved the efficacy. Notably, there was no significant change in blood parameters, kidney and liver functions upon combinatorial treatment of SCR7 and IR. Further, the co-treatment of SCR7 and IR resulted in a significant increase in unrepaired DSBs within cancer cells compared to either of the agent alone. Anatomy, histology, and other studies in tumor models confirmed the cumulative effects of both agents in activating apoptotic pathways to induce cytotoxicity by modulating DNA damage response and repair pathways. Thus, we report that SCR7 has the potential to reduce the side effects of radiotherapy by lowering its effective dose ex vivo and in mice tumor models, with implications in cancer therapy.
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Affiliation(s)
- Vidya Gopalakrishnan
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India.,Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, Karnataka, India.,Department of Zoology, St. Joseph's College (Autonomous), Irinjalakuda, Kerala, India
| | - Shivangi Sharma
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India.,Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, Karnataka, India
| | - Ujjayinee Ray
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India
| | - Meghana Manjunath
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, Karnataka, India.,Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Divya Lakshmanan
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India
| | - Supriya V Vartak
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India
| | - Vindya K Gopinatha
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India
| | - Mrinal Srivastava
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India.,Tata Institute of Fundamental Research, Hyderabad, Telangana, India
| | | | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, Karnataka, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India
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Manjunath M, Choudhary B, Raghavan SC. SCR7, a potent cancer therapeutic agent and a biochemical inhibitor of nonhomologous DNA end-joining. Cancer Rep (Hoboken) 2021; 4:e1341. [PMID: 33496064 PMCID: PMC8222562 DOI: 10.1002/cnr2.1341] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/15/2020] [Accepted: 12/21/2020] [Indexed: 12/11/2022] Open
Abstract
Background DNA double‐strand breaks (DSBs) are harmful to the cell as it could lead to genomic instability and cell death when left unrepaired. Homologous recombination and nonhomologous end‐joining (NHEJ) are two major DSB repair pathways, responsible for ensuring genome integrity in mammals. There have been multiple efforts using small molecule inhibitors to target these DNA repair pathways in cancers. SCR7 is a very well‐studied anticancer molecule that blocks NHEJ by targeting one of the critical enzymes, Ligase IV. Recent findings In this review, we have highlighted the anticancer effects of SCR7 as a single agent and in combination with other chemotherapeutic agents and radiation. SCR7 blocked NHEJ effectively both in vitro and ex vivo. SCR7 has been used for biochemical studies like chromosomal territory resetting and in understanding the role of repair proteins in cell cycle phases. Various forms of SCR7 and its derivatives are discussed. SCR7 is also used as a potent biochemical inhibitor of NHEJ, which has found its application in improving genome editing using a CRISPR‐Cas system. Conclusion SCR7 is a potent NHEJ inhibitor with unique properties and wide applications as an anticancer agent. Most importantly, SCR7 has become a handy aid for improving genome editing across different model systems.
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Affiliation(s)
- Meghana Manjunath
- Institute of Bioinformatics and Applied Biotechnology, Bangalore, India.,Manipal Academy of Higher Education, Manipal, India
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Bangalore, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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Gopalakrishnan V, Dahal S, Radha G, Sharma S, Raghavan SC, Choudhary B. Characterization of DNA double-strand break repair pathways in diffuse large B cell lymphoma. Mol Carcinog 2018; 58:219-233. [DOI: 10.1002/mc.22921] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 09/18/2018] [Accepted: 10/07/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Vidya Gopalakrishnan
- Institute of Bioinformatics and Applied Biotechnology; Electronics City; Bangalore India
- Manipal Academy of Higher Education; Manipal Karnataka India
| | - Sumedha Dahal
- Department of Biochemistry; Indian Institute of Science; Bangalore India
| | - Gudapureddy Radha
- Department of Biochemistry; Indian Institute of Science; Bangalore India
| | - Shivangi Sharma
- Department of Biochemistry; Indian Institute of Science; Bangalore India
| | | | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology; Electronics City; Bangalore India
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