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Li X, Zou L. BRCAness, DNA gaps, and gain and loss of PARP inhibitor-induced synthetic lethality. J Clin Invest 2024; 134:e181062. [PMID: 39007266 PMCID: PMC11245158 DOI: 10.1172/jci181062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/16/2024] Open
Abstract
Mutations in the tumor-suppressor genes BRCA1 and BRCA2 resulting in BRCA1/2 deficiency are frequently identified in breast, ovarian, prostate, pancreatic, and other cancers. Poly(ADP-ribose) polymerase (PARP) inhibitors (PARPis) selectively kill BRCA1/2-deficient cancer cells by inducing synthetic lethality, providing an effective biomarker-guided strategy for targeted cancer therapy. However, a substantial fraction of cancer patients carrying BRCA1/2 mutations do not respond to PARPis, and most patients develop resistance to PARPis over time, highlighting a major obstacle to PARPi therapy in the clinic. Recent studies have revealed that changes of specific functional defects of BRCA1/2-deficient cells, particularly their defects in suppressing and protecting single-stranded DNA gaps, contribute to the gain or loss of PARPi-induced synthetic lethality. These findings not only shed light on the mechanism of action of PARPis, but also lead to revised models that explain how PARPis selectively kill BRCA-deficient cancer cells. Furthermore, new mechanistic principles of PARPi sensitivity and resistance have emerged from these studies, generating potentially useful guidelines for predicting the PARPi response and design therapies for overcoming PARPi resistance. In this Review, we will discuss these recent studies and put them in context with the classic views of PARPi-induced synthetic lethality, aiming to stimulate the development of new therapeutic strategies to overcome PARPi resistance and improve PARPi therapy.
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2
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Zhou Y, Wang L, Lu Z, Yu Z, Ma L. Optimized minimal genome-wide human sgRNA library. Sci Rep 2023; 13:11569. [PMID: 37464007 PMCID: PMC10354020 DOI: 10.1038/s41598-023-38810-6] [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: 03/02/2023] [Accepted: 07/14/2023] [Indexed: 07/20/2023] Open
Abstract
Genome-wide clustered regularly interspaced short palindromic repeats (CRISPR)-based knockout screening is revolting the genetic analysis of a cellular or molecular phenotype in question but is challenged by the large size of single-guide RNA (sgRNA) library. Here we designed a minimal genome-wide human sgRNA library, H-mLib, which is composed of 21,159 sgRNA pairs assembled based on a dedicated selection strategy from all potential SpCas9/sgRNAs in the human genome. These sgRNA pairs were cloned into a dual-gRNA vector each targeting one gene, resulting in a compact library size nearly identical to the number of human protein-coding genes. The performance of the H-mLib was benchmarked to other CRISPR libraries in a proliferation screening conducted in K562 cells. We also identified groups of core essential genes and cell-type specific essential genes by comparing the screening results from the K562 and Jurkat cells. Together, the H-mLib exemplified high specificity and sensitivity in identifying essential genes while containing minimal library complexity, emphasizing its advantages and applications in CRISPR screening with limited cell numbers.
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Affiliation(s)
- Yangfan Zhou
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
- School of Life Sciences, Westlake University, 600 Dunyu Road, Hangzhou, 310030, Zhejiang, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, 310024, Zhejiang, China
| | - Lixia Wang
- School of Life Sciences, Westlake University, 600 Dunyu Road, Hangzhou, 310030, Zhejiang, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, 310024, Zhejiang, China
- School of Life Sciences, Fudan University, Shanghai, 200433, China
| | - Zhike Lu
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
- School of Life Sciences, Westlake University, 600 Dunyu Road, Hangzhou, 310030, Zhejiang, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, 310024, Zhejiang, China
| | - Zhenxing Yu
- School of Life Sciences, Westlake University, 600 Dunyu Road, Hangzhou, 310030, Zhejiang, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, 310024, Zhejiang, China
- School of Life Sciences, Fudan University, Shanghai, 200433, China
| | - Lijia Ma
- School of Life Sciences, Westlake University, 600 Dunyu Road, Hangzhou, 310030, Zhejiang, China.
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, 310024, Zhejiang, China.
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, 310024, Zhejiang, China.
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Veneziani AC, Scott C, Wakefield MJ, Tinker AV, Lheureux S. Fighting resistance: post-PARP inhibitor treatment strategies in ovarian cancer. Ther Adv Med Oncol 2023; 15:17588359231157644. [PMID: 36872947 PMCID: PMC9983116 DOI: 10.1177/17588359231157644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 01/30/2023] [Indexed: 03/06/2023] Open
Abstract
Poly (ADP-ribose) polymerase inhibitors (PARPis) represent a therapeutic milestone in the management of epithelial ovarian cancer. The concept of 'synthetic lethality' is exploited by PARPi in tumors with defects in DNA repair pathways, particularly homologous recombination deficiency. The use of PARPis has been increasing since its approval as maintenance therapy, particularly in the first-line setting. Therefore, resistance to PARPi is an emerging issue in clinical practice. It brings an urgent need to elucidate and identify the mechanisms of PARPi resistance. Ongoing studies address this challenge and investigate potential therapeutic strategies to prevent, overcome, or re-sensitize tumor cells to PARPi. This review aims to summarize the mechanisms of resistance to PARPi, discuss emerging strategies to treat patients post-PARPi progression, and discuss potential biomarkers of resistance.
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Affiliation(s)
- Ana C Veneziani
- Division of Medical Oncology and Haematology, Princess Margaret Cancer Centre, Toronto, ON, Canada
| | - Clare Scott
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia.,Royal Women's Hospital, Parkville, VIC, Australia.,Sir Peter MacCallum Department of Oncology, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Matthew J Wakefield
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
| | - Anna V Tinker
- BC Cancer Agency, Medical Oncology Vancouver, Canada
| | - Stephanie Lheureux
- Division of Medical Oncology and Haematology, Princess Margaret Cancer Centre, 610 University Ave, Toronto, ON M5B 2M9, Canada
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Khatib JB, Schleicher EM, Jackson LM, Dhoonmoon A, Moldovan GL, Nicolae CM. Complementary CRISPR genome-wide genetic screens in PARP10-knockout and overexpressing cells identify synthetic interactions for PARP10-mediated cellular survival. Oncotarget 2022; 13:1078-1091. [PMID: 36187556 PMCID: PMC9518689 DOI: 10.18632/oncotarget.28277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 09/18/2022] [Indexed: 01/17/2023] Open
Abstract
PARP10 is a mono-ADP-ribosyltransferase with multiple cellular functions, including proliferation, apoptosis, metabolism and DNA repair. PARP10 is overexpressed in a significant proportion of tumors, particularly breast and ovarian cancers. Identifying genetic susceptibilities based on PARP10 expression levels is thus potentially relevant for finding new targets for precision oncology. Here, we performed a series of CRISPR genome-wide loss-of-function screens in isogenic control and PARP10-overexpressing or PARP10-knockout cell lines, to identify genetic determinants of PARP10-mediated cellular survival. We found that PARP10-overexpressing cells rely on multiple DNA repair genes for survival, including ATM, the master regulator of the DNA damage checkpoint. Moreover, we show that PARP10 impacts the recruitment of ATM to nascent DNA upon replication stress. Finally, we identify the CDK2-Cyclin E1 complex as essential for proliferation of PARP10-knockout cells. Our work identifies a network of functionally relevant PARP10 synthetic interactions, and reveals a set of factors which can potentially be targeted in personalized cancer therapy.
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Affiliation(s)
- Jude B Khatib
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.,These authors contributed equally to this work
| | - Emily M Schleicher
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.,These authors contributed equally to this work
| | - Lindsey M Jackson
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Ashna Dhoonmoon
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - George-Lucian Moldovan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Claudia M Nicolae
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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Golder A, Nelson L, Tighe A, Barnes B, Coulson-Gilmer C, Morgan R, McGrail J, Taylor S. Multiple-low-dose therapy: effective killing of high-grade serous ovarian cancer cells with ATR and CHK1 inhibitors. NAR Cancer 2022; 4:zcac036. [PMID: 36381271 PMCID: PMC9653014 DOI: 10.1093/narcan/zcac036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 09/02/2022] [Accepted: 10/27/2022] [Indexed: 11/13/2022] Open
Abstract
High-grade serous ovarian cancer (HGSOC) is an aggressive disease that typically develops drug resistance, thus novel biomarker-driven strategies are required. Targeted therapy focuses on synthetic lethality—pioneered by PARP inhibition of BRCA1/2-mutant disease. Subsequently, targeting the DNA replication stress response (RSR) is of clinical interest. However, further mechanistic insight is required for biomarker discovery, requiring sensitive models that closely recapitulate HGSOC. We describe an optimized proliferation assay that we use to screen 16 patient-derived ovarian cancer models (OCMs) for response to RSR inhibitors (CHK1i, WEE1i, ATRi, PARGi). Despite genomic heterogeneity characteristic of HGSOC, measurement of OCM proliferation was reproducible and reflected intrinsic tumour-cell properties. Surprisingly, RSR targeting drugs were not interchangeable, as sensitivity to the four inhibitors was not correlated. Therefore, to overcome RSR redundancy, we screened the OCMs with all two-, three- and four-drug combinations in a multiple-low-dose strategy. We found that low-dose CHK1i-ATRi had a potent anti-proliferative effect on 15 of the 16 OCMs, and was synergistic with potential to minimise treatment resistance and toxicity. Low-dose ATRi-CHK1i induced replication catastrophe followed by mitotic exit and post-mitotic arrest or death. Therefore, this study demonstrates the potential of the living biobank of OCMs as a drug discovery platform for HGSOC.
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Affiliation(s)
- Anya Golder
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, and Manchester Cancer Research Centre , Wilmslow Road, Manchester M20 4GJ, UK
| | - Louisa Nelson
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, and Manchester Cancer Research Centre , Wilmslow Road, Manchester M20 4GJ, UK
| | - Anthony Tighe
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, and Manchester Cancer Research Centre , Wilmslow Road, Manchester M20 4GJ, UK
| | - Bethany Barnes
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, and Manchester Cancer Research Centre , Wilmslow Road, Manchester M20 4GJ, UK
| | - Camilla Coulson-Gilmer
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, and Manchester Cancer Research Centre , Wilmslow Road, Manchester M20 4GJ, UK
| | - Robert D Morgan
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, and Manchester Cancer Research Centre , Wilmslow Road, Manchester M20 4GJ, UK
- Department of Medical Oncology, The Christie NHS Foundation Trust , Wilmslow Rd, Manchester M20 4BX, UK
| | - Joanne C McGrail
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, and Manchester Cancer Research Centre , Wilmslow Road, Manchester M20 4GJ, UK
| | - Stephen S Taylor
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, and Manchester Cancer Research Centre , Wilmslow Road, Manchester M20 4GJ, UK
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The TIP60-ATM axis regulates replication fork stability in BRCA-deficient cells. Oncogenesis 2022; 11:33. [PMID: 35717336 PMCID: PMC9206655 DOI: 10.1038/s41389-022-00410-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 06/01/2022] [Accepted: 06/07/2022] [Indexed: 11/17/2022] Open
Abstract
Maintenance of replication fork stability is essential for genome preservation. Stalled replication forks can be reversed by translocases such as SMARCAL1, and unless protected through the activity of the BRCA pathway, are subsequently subjected to nucleolytic degradation. The ATM and ATR kinases are master regulators of the DNA damage response. ATM activation upon DNA damage is mediated by the acetyltransferase TIP60. Here, we show that the TIP60-ATM pathway promotes replication fork reversal by recruiting SMARCAL1 to stalled forks. This enables fork degradation in BRCA-deficient cells. We also show that this ATM activity is not shared by ATR. Moreover, we performed a series of genome-wide CRISPR knockout genetic screens to identify genetic determinants of the cellular sensitivity to ATM inhibition in wildtype and BRCA2-knockout cells, and validated the top hits from multiple screens. We provide a valuable list of common genes which regulate the response to multiple ATM inhibitors. Importantly, we identify a differential response of wildtype and BRCA2-deficient cells to these inhibitors. In BRCA2-knockout cells, DNA repair genes (including RAD17, MDC1, and USP28) were essential for survival upon ATM inhibitor treatment, which was not the case in wild-type cells. These findings may eventually help guide the way for rational deployment of ATM inhibitors in the clinic.
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