Pub Date : 2025-05-01DOI: 10.1016/j.dnarep.2025.103841
Matthew R. Jordan , Pamela L. Mendoza-Munoz , Katherine S. Pawelczak , John J. Turchi
DNA damage occurs from both endogenous and exogenous sources and DNA damaging agents are a mainstay in cancer therapeutics. DNA damage sensors (DDS) are proteins that recognize and bind to unique DNA structures that arise from direct DNA damage or replication stress and are the first step in the DNA damage response (DDR). DNA damage sensors are responsible for recruiting transducer proteins that signal downstream DNA repair pathways. As the initiating proteins, DDS are excellent candidates for anti-cancer drug targeting to limit DDR activation. Here, we review four major DDS: PARP1, RPA, Ku, and the MRN complex. We briefly describe the cellular DDS functions before analyzing the structural mechanisms of DNA damage sensing. Lastly, we examine the current state of the field towards inhibiting each DDS for anti-cancer therapeutics and broadly discuss the therapeutic potential for DDS targeting.
{"title":"Targeting DNA damage sensors for cancer therapy","authors":"Matthew R. Jordan , Pamela L. Mendoza-Munoz , Katherine S. Pawelczak , John J. Turchi","doi":"10.1016/j.dnarep.2025.103841","DOIUrl":"10.1016/j.dnarep.2025.103841","url":null,"abstract":"<div><div>DNA damage occurs from both endogenous and exogenous sources and DNA damaging agents are a mainstay in cancer therapeutics. DNA damage sensors (DDS) are proteins that recognize and bind to unique DNA structures that arise from direct DNA damage or replication stress and are the first step in the DNA damage response (DDR). DNA damage sensors are responsible for recruiting transducer proteins that signal downstream DNA repair pathways. As the initiating proteins, DDS are excellent candidates for anti-cancer drug targeting to limit DDR activation. Here, we review four major DDS: PARP1, RPA, Ku, and the MRN complex. We briefly describe the cellular DDS functions before analyzing the structural mechanisms of DNA damage sensing. Lastly, we examine the current state of the field towards inhibiting each DDS for anti-cancer therapeutics and broadly discuss the therapeutic potential for DDS targeting.</div></div>","PeriodicalId":300,"journal":{"name":"DNA Repair","volume":"149 ","pages":"Article 103841"},"PeriodicalIF":3.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-01DOI: 10.1016/j.dnarep.2025.103842
Cindy Meister, Ronald P. Wong, Zhi-Hoon Park, Helle D. Ulrich
Polyubiquitylation of the replication factor PCNA activates the replicative bypass of DNA lesions via an error-free pathway involving template switching. However, the mechanism by which the K63-linked polyubiquitin chains facilitate damage bypass is poorly understood. Intriguingly, stable fusions of linear ubiquitin oligomers to PCNA, designed as mimics of the native K63-linked chains, are not functional, while enzymatic modification of PCNA with linear chains supports template switching in budding yeast. To investigate the cause of this discrepancy, we have taken an alternative approach to identify the features of polyubiquitylated PCNA essential for activating damage bypass. We designed linear, non-cleavable ubiquitin constructs that can be recruited non-covalently to PCNA via a PIP motif. We found that these partially suppress the damage sensitivity and elevated spontaneous mutation rates of yeast strains defective in PCNA ubiquitylation. Genetic analysis confirms that this rescue is due to an activation of the template switching pathway. Surprisingly, even the recruitment of monoubiquitin units promotes activity in this setting. These observations suggest that the reversibility of ubiquitin’s association with PCNA is more important than the actual linkage of the polyubiquitin chain. Thus, our study highlights the dynamic nature of ubiquitin signaling in the context of DNA damage bypass.
{"title":"Reversible association of ubiquitin with PCNA is important for template switching in S. cerevisiae","authors":"Cindy Meister, Ronald P. Wong, Zhi-Hoon Park, Helle D. Ulrich","doi":"10.1016/j.dnarep.2025.103842","DOIUrl":"10.1016/j.dnarep.2025.103842","url":null,"abstract":"<div><div>Polyubiquitylation of the replication factor PCNA activates the replicative bypass of DNA lesions via an error-free pathway involving template switching. However, the mechanism by which the K63-linked polyubiquitin chains facilitate damage bypass is poorly understood. Intriguingly, stable fusions of linear ubiquitin oligomers to PCNA, designed as mimics of the native K63-linked chains, are not functional, while enzymatic modification of PCNA with linear chains supports template switching in budding yeast. To investigate the cause of this discrepancy, we have taken an alternative approach to identify the features of polyubiquitylated PCNA essential for activating damage bypass. We designed linear, non-cleavable ubiquitin constructs that can be recruited non-covalently to PCNA via a PIP motif. We found that these partially suppress the damage sensitivity and elevated spontaneous mutation rates of yeast strains defective in PCNA ubiquitylation. Genetic analysis confirms that this rescue is due to an activation of the template switching pathway. Surprisingly, even the recruitment of monoubiquitin units promotes activity in this setting. These observations suggest that the reversibility of ubiquitin’s association with PCNA is more important than the actual linkage of the polyubiquitin chain. Thus, our study highlights the dynamic nature of ubiquitin signaling in the context of DNA damage bypass.</div></div>","PeriodicalId":300,"journal":{"name":"DNA Repair","volume":"149 ","pages":"Article 103842"},"PeriodicalIF":3.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143902249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-17DOI: 10.1016/j.dnarep.2025.103839
Yaping Huang , Guo-Min Li
The DnaJ heat shock protein family (HSP40) is the biggest chaperone family in mammalian cells, mainly functioning as cochaperone of HSP70 to maintain proteostasis and cellular homeostasis under both normal and stressful conditions. Although the functions of HSP70s have been extensively studied in diverse biological pathways and senesces including genome maintenance, HSP40s’ biological functions at basal state or in response to exogenous insults remain largely under-investigated. Emerging evidence shows that HSP40 proteins participate in genome maintenance pathways and modulate cancer therapy efficacy. This review aims to summarize recent progresses regarding HSP40’s functions in genome maintenance and cancer therapy, and provides hints for future studies in the field.
{"title":"Role of HSP40 proteins in genome maintenance, insulin signaling and cancer therapy","authors":"Yaping Huang , Guo-Min Li","doi":"10.1016/j.dnarep.2025.103839","DOIUrl":"10.1016/j.dnarep.2025.103839","url":null,"abstract":"<div><div>The DnaJ heat shock protein family (HSP40) is the biggest chaperone family in mammalian cells, mainly functioning as cochaperone of HSP70 to maintain proteostasis and cellular homeostasis under both normal and stressful conditions. Although the functions of HSP70s have been extensively studied in diverse biological pathways and senesces including genome maintenance, HSP40s’ biological functions at basal state or in response to exogenous insults remain largely under-investigated. Emerging evidence shows that HSP40 proteins participate in genome maintenance pathways and modulate cancer therapy efficacy. This review aims to summarize recent progresses regarding HSP40’s functions in genome maintenance and cancer therapy, and provides hints for future studies in the field.</div></div>","PeriodicalId":300,"journal":{"name":"DNA Repair","volume":"149 ","pages":"Article 103839"},"PeriodicalIF":3.0,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143855996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-15DOI: 10.1016/j.dnarep.2025.103836
Obed A. Aning , Albertas Dvirnas , My Nyblom , Jens Krog , Johanna Carlson , Pegah Johansson , Tobias Ambjörnsson , Fredrik Westerlund
The main information in DNA is its four-letter sequence that builds up the genetic information and that is traditionally read using sequencing methodologies. DNA can, however, also carry other important information, such as epigenetic marks and DNA damage. This information has recently been visualized along single DNA molecules using fluorescent labels. Quantifying fluorescent labels along DNA is done by counting the number of “dots” per length of each DNA molecule on DNA stretched on a glass surface. So far, a major challenge has been the lack of standardized data analysis tools. Focusing on DNA damage, we here present a Matlab-based automated software, Stained DNA Dot Detection (SD3), which uses a robust method for finding DNA molecules and estimating the number of dots along each molecule. We have validated SD3 by comparing the outcome to manual analysis using DNA extracted from cells exposed to H2O2 as a model system. Our results show that SD3 achieves high accuracy and reduced analysis time relative to manual counting. SD3 allows the user to define specific parameters regarding the DNA molecule and the location of dots to include during analysis via a user-friendly interface. We foresee that our open-source software can have broad use in the analysis of single DNA molecules and their modifications in research and in diagnostics.
{"title":"Stained DNA Dot Detection (SD3): An automated tool for quantifying fluorescent features along single stretched DNA molecules","authors":"Obed A. Aning , Albertas Dvirnas , My Nyblom , Jens Krog , Johanna Carlson , Pegah Johansson , Tobias Ambjörnsson , Fredrik Westerlund","doi":"10.1016/j.dnarep.2025.103836","DOIUrl":"10.1016/j.dnarep.2025.103836","url":null,"abstract":"<div><div>The main information in DNA is its four-letter sequence that builds up the genetic information and that is traditionally read using sequencing methodologies. DNA can, however, also carry other important information, such as epigenetic marks and DNA damage. This information has recently been visualized along single DNA molecules using fluorescent labels. Quantifying fluorescent labels along DNA is done by counting the number of “dots” per length of each DNA molecule on DNA stretched on a glass surface. So far, a major challenge has been the lack of standardized data analysis tools. Focusing on DNA damage, we here present a Matlab-based automated software, Stained DNA Dot Detection (SD<sup>3</sup>), which uses a robust method for finding DNA molecules and estimating the number of dots along each molecule. We have validated SD<sup>3</sup> by comparing the outcome to manual analysis using DNA extracted from cells exposed to H<sub>2</sub>O<sub>2</sub> as a model system. Our results show that SD<sup>3</sup> achieves high accuracy and reduced analysis time relative to manual counting. SD<sup>3</sup> allows the user to define specific parameters regarding the DNA molecule and the location of dots to include during analysis via a user-friendly interface. We foresee that our open-source software can have broad use in the analysis of single DNA molecules and their modifications in research and in diagnostics.</div></div>","PeriodicalId":300,"journal":{"name":"DNA Repair","volume":"149 ","pages":"Article 103836"},"PeriodicalIF":3.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143882273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xeroderma Pigmentosum group C (XP-C) is a rare, inherited autosomal recessive genetic disorder characterized by extreme sensitivity to ultraviolet (UV) radiation, caused by mutations in the XPC gene. Among the eight XP complementation groups, XP-C is the most prevalent worldwide. Here, we present an 8-year-old girl with multiple discrete hyperpigmented and depigmented macules on her face, neck, upper chest, and arms. Her skin abnormalities first appeared around the age of one as dark patches on the face and neck, progressively worsening with sun exposure. The patient was also diagnosed with bilateral blepharoconjunctivitis and severe dry eye syndrome. Histopathological examination revealed hyperkeratinization of stratified squamous epithelium. Moreover, the proband also exhibited increased expression of PCNA, p53, and cleaved-caspase 3. Genetic analysis identified a novel homozygous pathogenic variant in the XPC gene at c.2420 + 1 G>C. We also demonstrated that the mutant can localize to the site of DNA damage, but it is defective in CPD repair. Among all reported intronic XPC variants, the XPC:c.2420 + 1 G>C mutation seems to have a significant impact as it results in a one-base-pair deletion at the splice donor site of exon 13. This leads to a frameshift, triggering nonsense-mediated decay and causing a premature stop codon in exon 14 of the XPC gene. Thus, the patient is advised to undergo regular examinations to monitor the progression of the disease and the development of precancerous lesions.
{"title":"Identification of a novel pathogenic XPC:c.2420 + 1 G>C variant in a patient with xeroderma pigmentosum","authors":"Estu Ratnangganajati , Mukhlissul Faatih , Zulvikar Syambani Ulhaq","doi":"10.1016/j.dnarep.2025.103837","DOIUrl":"10.1016/j.dnarep.2025.103837","url":null,"abstract":"<div><div>Xeroderma Pigmentosum group C (XP-C) is a rare, inherited autosomal recessive genetic disorder characterized by extreme sensitivity to ultraviolet (UV) radiation, caused by mutations in the <em>XPC</em> gene. Among the eight XP complementation groups, XP-C is the most prevalent worldwide. Here, we present an 8-year-old girl with multiple discrete hyperpigmented and depigmented macules on her face, neck, upper chest, and arms. Her skin abnormalities first appeared around the age of one as dark patches on the face and neck, progressively worsening with sun exposure. The patient was also diagnosed with bilateral blepharoconjunctivitis and severe dry eye syndrome. Histopathological examination revealed hyperkeratinization of stratified squamous epithelium. Moreover, the proband also exhibited increased expression of PCNA, p53, and cleaved-caspase 3. Genetic analysis identified a novel homozygous pathogenic variant in the <em>XPC</em> gene at c.2420 + 1 G>C. We also demonstrated that the mutant can localize to the site of DNA damage, but it is defective in CPD repair. Among all reported intronic <em>XPC</em> variants, the <em>XPC</em>:c.2420 + 1 G>C mutation seems to have a significant impact as it results in a one-base-pair deletion at the splice donor site of exon 13. This leads to a frameshift, triggering nonsense-mediated decay and causing a premature stop codon in exon 14 of the <em>XPC</em> gene. Thus, the patient is advised to undergo regular examinations to monitor the progression of the disease and the development of precancerous lesions.</div></div>","PeriodicalId":300,"journal":{"name":"DNA Repair","volume":"149 ","pages":"Article 103837"},"PeriodicalIF":3.0,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-09DOI: 10.1016/j.dnarep.2025.103835
Amanda K. McCullough , Irina G. Minko , Michael M. Luzadder , Jamie T. Zuckerman , Vladimir L. Vartanian , Pawel Jaruga , Miral Dizdaroglu , R. Stephen Lloyd
{"title":"Corrigendum to “Role of NEIL1 in genome maintenance” [DNA Repair 148 (2025) 103820]","authors":"Amanda K. McCullough , Irina G. Minko , Michael M. Luzadder , Jamie T. Zuckerman , Vladimir L. Vartanian , Pawel Jaruga , Miral Dizdaroglu , R. Stephen Lloyd","doi":"10.1016/j.dnarep.2025.103835","DOIUrl":"10.1016/j.dnarep.2025.103835","url":null,"abstract":"","PeriodicalId":300,"journal":{"name":"DNA Repair","volume":"149 ","pages":"Article 103835"},"PeriodicalIF":3.0,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-08DOI: 10.1016/j.dnarep.2025.103832
Yingying Meng, Lee Zou
R-loops are dynamic three-stranded nucleic acid structures that form naturally during transcription. These structures typically arise when the newly synthesized RNA hybridizes with the DNA template strand, displacing the non-template DNA strand. R-loops are not only found at protein-coding genes but also in regions producing non-coding RNAs, such as telomeres, centromeres, ribosomal DNA genes, and transfer RNA genes. While R-loops are regulated by both the process of transcription and chromatin structures, they also play a critical role in modulating transcription and influencing the chromatin landscape. Moreover, the interactions between R-loops, transcription, and chromatin are essential for maintaining genome stability and are often disrupted in various human diseases. In this review, we will explore recent insights into the intricate relationship between R-loops and transcription, as well as their crosstalk with chromatin.
{"title":"Building an integrated view of R-loops, transcription, and chromatin","authors":"Yingying Meng, Lee Zou","doi":"10.1016/j.dnarep.2025.103832","DOIUrl":"10.1016/j.dnarep.2025.103832","url":null,"abstract":"<div><div>R-loops are dynamic three-stranded nucleic acid structures that form naturally during transcription. These structures typically arise when the newly synthesized RNA hybridizes with the DNA template strand, displacing the non-template DNA strand. R-loops are not only found at protein-coding genes but also in regions producing non-coding RNAs, such as telomeres, centromeres, ribosomal DNA genes, and transfer RNA genes. While R-loops are regulated by both the process of transcription and chromatin structures, they also play a critical role in modulating transcription and influencing the chromatin landscape. Moreover, the interactions between R-loops, transcription, and chromatin are essential for maintaining genome stability and are often disrupted in various human diseases. In this review, we will explore recent insights into the intricate relationship between R-loops and transcription, as well as their crosstalk with chromatin.</div></div>","PeriodicalId":300,"journal":{"name":"DNA Repair","volume":"149 ","pages":"Article 103832"},"PeriodicalIF":3.0,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-08DOI: 10.1016/j.dnarep.2025.103833
Bareket Goldstein, Suad Sheikh-Suliman, Anna Bakhrat, Uri Abdu
The 9–1–1 complex, comprising the Rad9, Hus1 and Rad1 proteins, is believed to operate as a component of a DNA damage checkpoint pathway. Our initial analysis of the Drosophila hus1 gene showed that Hus1 plays a dual role in meiosis, regulating both meiotic DNA damage checkpoint and homologous recombination repair. In this study, we further analyzed the meiotic roles of another protein in the complex, Rad9, which has two alternatively spliced forms, Rad9A and Rad9B. Using CRISPR/Cas9, we generated flies mutant for both rad9 isoforms. We found that, similarly to hus1, mutations in rad9 lead to female sterility. Also, double-strand DNA breaks (DSBs) that form during meiosis are not processed efficiently, and the DNA within the oocyte nucleus fails to form its characteristic shape in rad9 mutants. On the other hand, the hus1 mutation completely disrupts checkpoint activation in DSB repair enzyme mutants, whereas the rad9 mutation only partially impairs checkpoint activation in this context. Moreover, spatial rescue experiments revealed that Rad9B is efficient in repairing meiotic DSBs, while Rad9A is not. Furthermore, we found that female fertility in rad9 mutants depends on early efficient meiotic DSB repair but not on karyosome formation. In summary, our results demonstrate a differential role of Rad9 alternatively spliced forms during Drosophila meiosis in oogenesis, and while former studies showed that Hus1 is sufficient for the effective activation of the meiotic recombination checkpoint, our results revealed that this is not true for Rad9.
{"title":"The differential roles of rad9 alternatively spliced forms in double- strand DNA break repair during Drosophila meiosis","authors":"Bareket Goldstein, Suad Sheikh-Suliman, Anna Bakhrat, Uri Abdu","doi":"10.1016/j.dnarep.2025.103833","DOIUrl":"10.1016/j.dnarep.2025.103833","url":null,"abstract":"<div><div>The 9–1–1 complex, comprising the Rad9, Hus1 and Rad1 proteins, is believed to operate as a component of a DNA damage checkpoint pathway. Our initial analysis of the <em>Drosophila hus1</em> gene showed that Hus1 plays a dual role in meiosis, regulating both meiotic DNA damage checkpoint and homologous recombination repair. In this study, we further analyzed the meiotic roles of another protein in the complex, Rad9, which has two alternatively spliced forms, Rad9A and Rad9B. Using CRISPR/Cas9, we generated flies mutant for both <em>rad9</em> isoforms. We found that, similarly to <em>hus1</em>, mutations in <em>rad9</em> lead to female sterility. Also, double-strand DNA breaks (DSBs) that form during meiosis are not processed efficiently, and the DNA within the oocyte nucleus fails to form its characteristic shape in <em>rad9</em> mutants. On the other hand, the <em>hus1</em> mutation completely disrupts checkpoint activation in DSB repair enzyme mutants, whereas the <em>rad9</em> mutation only partially impairs checkpoint activation in this context. Moreover, spatial rescue experiments revealed that Rad9B is efficient in repairing meiotic DSBs, while Rad9A is not. Furthermore, we found that female fertility in <em>rad9</em> mutants depends on early efficient meiotic DSB repair but not on karyosome formation. In summary, our results demonstrate a differential role of Rad9 alternatively spliced forms during <em>Drosophila</em> meiosis in oogenesis, and while former studies showed that Hus1 is sufficient for the effective activation of the meiotic recombination checkpoint, our results revealed that this is not true for Rad9.</div></div>","PeriodicalId":300,"journal":{"name":"DNA Repair","volume":"149 ","pages":"Article 103833"},"PeriodicalIF":3.0,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Advanced epithelial ovarian cancer of the high-grade serous subtype (HGSOC) remains a significant clinical challenge due to the development of resistance to current platinum-based chemotherapies. PARP1/2 inhibitors (PARPi) exploit the well-characterised homologous recombination repair deficiency (HRD) in HGSOC and offer an effective targeted approach to treatment. Several clinical trials demonstrated that PARPi (olaparib, rucaparib, niraparib) significantly improved progression-free survival (PFS) in HGSOC in the recurrent maintenance setting. However, 40–70 % of patients develop Resistance to PARPi presenting an ongoing challenge in the clinic. Therefore, there is an unmet need for novel targeted therapies and biomarkers to identify intrinsic or acquired resistance to PARPi in ovarian cancer. Understanding the mechanisms of resistance to PARPi is crucial for identifying molecular vulnerabilities, developing effective biomarkers for patient stratification and guiding treatment decisions. Here, we summarise the current landscape of mechanisms associated with PARPi resistance such as restored homologous recombination repair functionality, replication fork stability and alterations to PARP1 and PARP2 and the DNA damage response. We highlight the role of circulating tumour DNA (ctDNA) in identifying acquired resistance biomarkers and its potential in guiding ‘real-time’ treatment decisions. Moreover, we explore other innovative treatment strategies aimed at overcoming specific resistance mechanisms, including the inhibition of ATR, WEE1 and POLQ. We also examine the role of PARPi rechallenge in patients with acquired resistance.
{"title":"PARP inhibitors in ovarian cancer: Mechanisms of resistance and implications to therapy","authors":"Sanat Kulkarni , Nethmin Seneviratne , Çağla Tosun , Srinivasan Madhusudan","doi":"10.1016/j.dnarep.2025.103830","DOIUrl":"10.1016/j.dnarep.2025.103830","url":null,"abstract":"<div><div>Advanced epithelial ovarian cancer of the high-grade serous subtype (HGSOC) remains a significant clinical challenge due to the development of resistance to current platinum-based chemotherapies. PARP1/2 inhibitors (PARPi) exploit the well-characterised homologous recombination repair deficiency (HRD) in HGSOC and offer an effective targeted approach to treatment. Several clinical trials demonstrated that PARPi (olaparib, rucaparib, niraparib) significantly improved progression-free survival (PFS) in HGSOC in the recurrent maintenance setting. However, 40–70 % of patients develop Resistance to PARPi presenting an ongoing challenge in the clinic. Therefore, there is an unmet need for novel targeted therapies and biomarkers to identify intrinsic or acquired resistance to PARPi in ovarian cancer. Understanding the mechanisms of resistance to PARPi is crucial for identifying molecular vulnerabilities, developing effective biomarkers for patient stratification and guiding treatment decisions. Here, we summarise the current landscape of mechanisms associated with PARPi resistance such as restored homologous recombination repair functionality, replication fork stability and alterations to PARP1 and PARP2 and the DNA damage response. We highlight the role of circulating tumour DNA (ctDNA) in identifying acquired resistance biomarkers and its potential in guiding ‘real-time’ treatment decisions. Moreover, we explore other innovative treatment strategies aimed at overcoming specific resistance mechanisms, including the inhibition of ATR, WEE1 and POLQ. We also examine the role of PARPi rechallenge in patients with acquired resistance.</div></div>","PeriodicalId":300,"journal":{"name":"DNA Repair","volume":"149 ","pages":"Article 103830"},"PeriodicalIF":3.0,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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