Exploring and comparing adverse events between PARP inhibitors

Therapeutic advances and application of PARP inhibitors in breast cancer

Targeting of DNA repair pathway is the main therapeutic approach for BRCA1 and BRCA2 associated tumors, including breast cancer. BRCA1/2 genes play a pivotal role in HRR pathway. Mutations in BRCA1/2 leads to DDR deficiency, which cause the increasing of genome instability, thus rendering cancer cells vulnerable to inhibition of DNA repair related proteins, such as PARP1. Pre-clinical studies has demonstrated that cancer cells with BRCA1/2 deficient are sensitive to PARPi, which are an emerging class of small molecule drug. Several clinical trials demonstrated the promising efficacy of PARP inhibitors for BRCA1/2 mutated breast cancer patient through selectively induce synthetic lethality cancer cells. Currently, four PARP inhibitors had been approved by FDA for clinical use. PARPi demonstrated to improve progression-free survival, while resistance to PARPi is inevitable. In this review article, we highlighted the advances in the PARPi clinical trials, resistance mechanism and coping strategies in breast cancer patients. We also summarized the international guideline and recommendations on PARP inhibitor usage in breast cancer.

Dual-responsive nanoscale ultrasound contrast agent as an oxidative stress amplifier for enhanced DNA damage in BRCA-proficient ovarian cancer

PARP inhibitor (PARPi)-based synthetic lethal therapies have displayed limited benefits in BRCA-proficient ovarian cancer. To potentiate the application of PARPi, an ultrasound contrast agent OLA-NDs for delivery of the PARPi olaparib (OLA) was established for enhancing DNA damage by blocking DNA repair. OLA-NDs were endowed with endogenous pH- and exogenous ultrasound (US)-responsiveness to target tumors, as well as contrast-enhanced US imaging for diagnostic and therapeutic integration. OLA-NDs could upregulate NOX4 to induce oxidative stress and sensitize BRCA wild-type A2780 cells to DNA oxidative damage through the utilization of ultrasound-targeted microbubble destruction (UTMD). In addition, the strategy further increased ROS production by interfering with mitochondrial function, thereby exacerbating DNA double-strand breaks (DSBs) and inducing mitochondria-mediated apoptosis. As a consequence, the combined application of UTMD and OLA-NDs demonstrated significant antitumor effects in vitro and in vivo. This combined strategy of amplifying oxidative damage improved lethality by promoting DNA DSBs and apoptosis with reduced adverse side effects, which would provide new insight for the clinical application of PARPi in BRCA-proficient ovarian cancer.

Computational design and structural insights into quinazoline-based lead molecules for targeting PARP10 in cancer therapy

Quinazoline scaffolds, a class of nitrogen-containing heterocyclic compounds, are considered a "privileged structure" in drug development due to their broad physiological activities and significant therapeutic potential. Many anti-breast cancer therapies are designed using this pharmacophore. Structural modifications such as halogen substitution and aromatic amino group insertion have been explored to improve the anticancer efficacy of quinazoline derivatives. Breast cancer continues to be the primary cause of cancer-related mortality among women, approximately 670,000 deaths globally in 2022, emphasizing the need for novel therapies. To combat multidrug resistance in breast cancer, new drug candidates targeting the Poly (ADP-ribose) polymerase (PARP) enzyme are being developed to improve chemotherapeutic efficacy and reduce toxicity. In this study, computational screening of 365 quinazoline derivatives was conducted to identify potential PARP inhibitors. Docking based screening identified three quinazoline scaffolds (RFAP77, RISA30, and RISAC) as top hits, demonstrating docking scores ranging from -8.41 to -9.31 kcal/mol and MM-GBSA binding free energy scores between -52.08 and -55.99 kcal/mol, compared to the reference approved inhibitor. ADMET analysis revealed favorable predicted drug-likeness profiles for the identified scaffolds. The structural stability of the docked PARP-ligand complexes was further investigated using molecular dynamics simulations (MDS). The computational simulations revealed significant conformational changes upon ligand binding, as evidenced by RMSD, RMSF, and hydrogen bond analyses. Essential dynamics analysis, including PCA-based FEL mapping, demonstrated energy minima profiles for all top docked PARP complexes. These computational findings highlight the potential of these scaffolds as promising candidates for further development as PARP inhibitors.

Targets and promising adjuvants for improving breast tumor response to radiotherapy

Breast cancer ranks among the most common cancers globally, with significant mortality rates in advanced stages. Despite progress in treatment, therapy resistance, particularly to radiotherapy, remains a major challenge. Radiosensitization offers a promising solution to enhance radiotherapy effectiveness. This approach specifically increases tumor cells' vulnerability to IR. Recent research has explored molecular targets and strategies to improve radiosensitivity in breast cancer. Examples include inhibiting DNA repair pathways, altering the TME, targeting signaling pathways, and using immunomodulators. These strategies not only amplify destructive effects of IR but may also reduce required radiation doses, thereby minimizing normal tissue injury. This review examines promising molecular targets and combination therapies to boost radiosensitivity in breast cancer. It also highlights recent advances in immune modulation, TME remodeling, targeted molecular therapy, and metabolic pathway targeting. These advancements offer insights into the future of radiosensitization research. By systematically analyzing these strategies, the article aims to provide a comprehensive understanding of radiosensitization's current state and future potential in breast cancer treatment.

Bibliometric analysis of research trends on the combination of radiotherapy and PARP inhibitors in solid tumors

Introduction

Radiotherapy has served as a cornerstone in cancer treatment for over a century. However, the efficacy of radiotherapy is often compromised by the intrinsic and acquired radioresistance of tumors, which can lead to treatment failure and disease recurrence. Recent advancements in preclinical and clinical research have highlighted the potential synergistic efficacy of combining radiotherapy with poly-ADP-ribose polymerase inhibitors (PARPi), offering promising therapeutic avenues for solid tumors. This study employs bibliometric analysis to systematically evaluate the evolution, trends, and intellectual landscape of research on the combination of radiotherapy and PARPi in solid tumors.

Methods

Publications addressing the combination of radiotherapy and PARPi for solid tumors between 2005 and 2024 were retrieved from the Web of Science Core Collection (WOSCC) database. Bibliometric assessments were conducted using VOSviewer and CiteSpace to analyze publication trends, collaborative networks, and research foci.

Results

A total of 901 articles were included. The United States dominated research output, with the University of Texas MD Anderson Cancer Center identified as the most productive institution. Hannah Farmer emerged as the most frequently cited author. Keywords co-occurrence analysis revealed a thematic shift from foundational studies on molecular mechanisms, such as DNA damage response and mechanism of action of PARPi, toward clinical investigations evaluating combination therapy efficacy and safety in trials.

Conclusion

This bibliometric analysis underscores the rapid growth of research on radiotherapy and PARPi combination therapy, with the United States maintaining a leading role due to its extensive scientific infrastructure and collaborative networks. The field has transitioned from mechanistic explorations to translational and clinical applications, reflecting progress toward therapeutic optimization. These findings provide a comprehensive overview of the knowledge structure within this domain and serve as a strategic reference for guiding future research priorities and clinical implementations.

Multifunctional nanoparticle-mediated targeting of metabolic reprogramming and DNA damage response pathways to treat drug-resistant triple-negative breast cancer

Multi-drug resistance and immunosuppressive triple-negative breast cancer (TNBC) is triggered by the Warburg effect, which promotes homologous recombination repair (HRR) and upregulates expression of P-glycoprotein (P-gp), in turn preventing DNA damage from chemotherapy and creating an immunosuppressive microenvironment. It is therefore of clinical relevance to develop an effective delivery system that targets metabolic reprogramming and DNA damage response pathways for the treatment of drug-resistant TNBC. Herein, a P-gp-inhibiting and GSH-responsive multifunctional drug carrier targeting integrin αvβ3 was synthesised for the delivery of Lonidamine-prodrug (M1, glycolysis inhibitor) and Senaparib (Se, Poly [ADP-ribose] polymerase inhibitor). The nanodrug delivery system (iPR@M1/Se nanoparticles) exhibit effective tumour penetration and P-gp inhibition, effectively inducing DNA damage and apoptosis in Olaparib-resistant TNBC cells in vitro, as well as a higher tumour inhibitory rate compared with that of Se (81.82 % ± 2.31 % vs 43.91 % ± 4.65 %) in vivo. Mechanistically, iPR@M1/Se nanoparticles not only reshaped the immunosuppressive microenvironment resulting from tumour glycolysis, but also downregulated the expression of HRR-related protein, fostering the cytoplasmic accumulation of DNA damage fragments, which induced activation of the cyclic GMP-AMP synthase (cGAS)/stimulator of interferon gene (STING) pathway. Experimental results show that iPR@M1/Se nanoparticles effectively promote dendritic cell maturation and T lymphocyte activation, which elicits long-term immune memory responses, and prevents tumour recurrence and lung metastasis. Therefore, these multifunctional nanoparticles have great potential and provide a clinically relevant and valuable option for Olaparib-resistant TNBC.

Joining of DNA breaks- interplay between DNA ligases and poly (ADP-ribose) polymerases

The joining of DNA single- and double-strand breaks (SSB and DSB) is essential for maintaining genome stability and integrity. While this is ultimately accomplished in human cells by the DNA ligases encoded by the LIG1, LIG3 and LIG4 genes, these enzymes are recruited to DNA breaks through specific interactions with proteins involved in break sensing and recognition and/or break processing. In this review, we focus on the interplay between the DNA break-activated poly (ADP-ribose) polymerases, PARP1 and PARP2, poly (ADP-ribose) (PAR) and the DNA ligases in DNA replication and repair. The most extensively studied example of this interplay is the recruitment of DNA ligase IIIα (LigIIIα) and other repair proteins to SSBs through an interaction between XRCC1, a scaffold protein and partner protein of nuclear LigIIIα, and PAR synthesized by PARP1 and to a lesser extent PARP2. Recently, these proteins have been implicated in a back-up pathway for joining Okazaki fragments that appears to have a critical function even in cells with no defect in the major LigI-dependent pathway. Finally, we discuss the effects of FDA-approved PARP1/2 inhibitors on DNA replication and repair in cancer and non-malignant cells and the potential utility of DNA ligase inhibitors as cancer therapeutics.

PARP inhibitors in ovarian cancer: Mechanisms of resistance and implications to therapy

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.

A battery-free nanofluidic intracellular delivery patch for internal organs

The targeted delivery of therapeutics to internal organs to, for example, promote healing or apoptosis holds promise in the treatment of numerous diseases1-4. Currently, the prevailing delivery modality relies on the circulation; however, this modality has substantial efficiency, safety and/or controllability limitations5-9. Here we report a battery-free, chipless, soft nanofluidic intracellular delivery (NanoFLUID) patch that provides enhanced and customized delivery of payloads in targeted internal organs. The chipless architecture and the flexible nature of thin functional layers facilitate integration with internal organs. The nanopore-microchannel-microelectrode structure enables safe, efficient and precise electroperforation of the cell membrane, which in turn accelerates intracellular payload transport by approximately 105 times compared with conventional diffusion methods while operating under relatively low-amplitude pulses (20 V). Through evaluations of the NanoFLUID patch in multiple in vivo scenarios, including treatment of breast tumours and acute injury in the liver and modelling tumour development, we validated its efficiency, safety and controllability for organ-targeted delivery. NanoFLUID-mediated in vivo transfection of a gene library also enabled efficient screening of essential drivers of breast cancer metastasis in the lung and liver. Through this approach, DUS2 was identified as a lung-specific metastasis driver. Thus, NanoFLUID represents an innovative bioelectronic platform for the targeted delivery of payloads to internal organs to treat various diseases and to uncover new insights in biology.

Olaparib as a rescue treatment in platinum-refractory germ-cell tumors: the IGG-02 phase II trial

BACKGROUND

Therapeutic options for patients with advanced germ-cell tumors (GCTs) after multiple relapses or resistant disease are limited. Olaparib is an inhibitor of poly (ADP-ribose) polymerase (PARP), an enzyme involved in DNA repair.

PATIENTS AND METHODS

In this proof-of principle open-label, single-arm, phase II trial of olaparib 300 mg twice daily in patients with relapsed/refractory metastatic germ-cell cancer [IGG-02 study (NCT02533765)], patient eligibility included failure after high-dose chemotherapy or after at least two different cisplatin-based regimens.

RESULTS

Between September 2015 and February 2019, 18 patients, with a median age of 39 years (range 22-61 years) were enrolled. Severe adverse events (AEs) were observed in seven patients. There were no partial responses, five cases (27.8%) with stable disease (SD) lasting 3, 4, 4, 7 and 43 months, and 13 (72.2%) progressive disease. A germline DNA repair profile panel showed only a BRCA1-mutated case associated with an SD lasting for 4 months. The long-lasting patient on olaparib (43 months) experienced a myelodisplastic syndrome (MDS) associated with the onset of a pathogenic mutation affecting PPM1D.

CONCLUSIONS

Olaparib as a single agent demonstrated no activity in heavily pretreated GCT patients. Future studies with PARP inhibitors should be planned in less-pretreated GCT patients based on molecular analysis to support better patient selection.

Pancreatic Cancer: Pathogenesis and Clinical Studies

Pancreatic cancer (PC) is a highly lethal malignancy, with pancreatic ductal adenocarcinoma (PDAC) being the most common and aggressive subtype, characterized by late diagnosis, aggressive progression, and resistance to conventional therapies. Despite advances in understanding its pathogenesis, including the identification of common genetic mutations (e.g., KRAS, TP53, CDKN2A, SMAD4) and dysregulated signaling pathways (e.g., KRAS-MAPK, PI3K-AKT, and TGF-β pathways), effective therapeutic strategies remain limited. Current treatment modalities including chemotherapy, targeted therapy, immunotherapy, radiotherapy, and emerging therapies such as antibody-drug conjugates (ADCs), chimeric antigen receptor T (CAR-T) cells, oncolytic viruses (OVs), cancer vaccines, and bispecific antibodies (BsAbs), face significant challenges. This review comprehensively summarizes these treatment approaches, emphasizing their mechanisms, limitations, and potential solutions, to overcome these bottlenecks. By integrating recent advancements and outlining critical challenges, this review aims to provide insights into future directions and guide the development of more effective treatment strategies for PC, with a specific focus on PDAC. Our work underscores the urgency of addressing the unmet needs in PDAC therapy and highlights promising areas for innovation in this field.

Duplexed CeTEAM drug biosensors reveal determinants of PARP inhibitor selectivity in cells

Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) targeting PARP1 and PARP2 have revolutionized cancer therapy by selectively killing cancer cells with defective DNA repair. However, achieving PARP1 or PARP2-selective inhibitors is difficult due to structural homology. Selectivity profiling is typically done with purified proteins, but these lack the complexity of intracellular environments and could therefore be inaccurate. Here, we duplex PARP1 L713F-GFP and PARP2 L269A-mCherry cellular target engagement by accumulation of mutant (CeTEAM) drug biosensors to systematically characterize binding and cell cycle alterations of 27 PARPi. Our results reveal that most PARPi are equipotent for both PARPs, including the next-generation drug, senaparib. However, benzimidazole carboxamide (niraparib) derivatives demonstrated PARP1-selective tendencies, while phthalazinones (olaparib) favored PARP2. AZD5305, a reported PARP1-selective inhibitor with characteristics of both series, was the exception and appears ∼1600-fold more potent toward PARP1. In agreement with current understanding, we see that trapping-associated S/G2-phase transitions positively correlate with PARP1/2 binding potency, while some potent binders, such as veliparib, did not - likely reflecting their allosteric influence on DNA retention. We also assessed the effect of the PARP1/2 active site component, histone PARylation factor 1, on intracellular PARPi binding and see that its depletion elicits slight deviations in apparent binding potency, while contributing additively to trapping-like phenotypes. The PARP1/2 CeTEAM platform thus provides a structural roadmap for the development of selective PARPi and should facilitate the discovery of targeted therapies. Furthermore, our results highlight that multiplexing CeTEAM biosensors and layered genetic perturbations can systematically profile determinants of intracellular drug selectivity.

Proteome-Wide Profiling of Olaparib Interactors Using a Biotinylated Photoaffinity Probe

Olaparib is a widely used PARP inhibitor for the treatment of BRCA-mutated cancers. To comprehensively understand the drug's clinical impact, measuring its interactions with intended on- and off-targets is crucial. In this study, olaparib's on- and off-targets were profiled using photoaffinity labeling, a powerful, proteome-wide method for studying the direct interactions between a drug and its protein targets. A novel photoaffinity probe was designed and used in a proteomic screening to discover novel targets of olaparib in the human proteome. The probe, incorporating a pre-installed biotin group, bypasses the limitations of using a copper(I)-catalyzed click reaction in cell lysates for reporter group conjugation and revealed a broad range of olaparib interactors, including previously unreported proteins, in a quantitative mass spectrometry-based proteomic screening using HeLa whole cell lysate. This study contributes to our current understanding of the pharmacology of olaparib and provides a valuable tool for elucidating drug interactors within cell lysates, potentially guiding the development of more targeted therapeutics with fewer off-targets.

Natural Products as Novel Therapeutic Agents for Triple-Negative Breast Cancer: Current Evidence, Mechanisms, Challenges, and Opportunities

Breast cancer (BC) tops the list of causes for female fatalities globally, with the elusive triple-negative breast cancer (TNBC) constituting 10-20% of all cases. Current clinical strategies for combating TNBC encompass a multifaceted approach, including surgical intervention, radiation therapy, chemotherapy, and advanced targeted drugs and immunotherapies. While these modalities have catalyzed significant advancements in TNBC management, lingering limitations continue to pose formidable challenges. There is an acute need for novel therapeutics in the realm of TNBC treatment. Natural products (NPs) have emerged as a rich reservoir for pharmaceutical innovation, owing to their extraordinary range of structures and physicochemical properties. Scholars have reported diverse evidence of NPs' efficacy against TNBC. This review aims to comprehensively explore the bioactive constituents, specifics and commonalities of chemical structure, and pharmacological mechanisms of NPs, specifically examining their multifaceted roles in impeding TNBC. NPs, which have recently garnered significant interest, are intriguing in terms of their capacity to combat TNBC through multifaceted mechanisms, including the suppression of tumor cell proliferation, the induction of apoptosis, and the inhibition of tumor metastasis. These natural agents primarily encompass a range of compounds, including terpenoids, glycosides, phenolic compounds, and alkaloids. An in-depth exploration has unveiled their involvement in key signaling pathways, including the transforming growth factor-beta (TGF-β), vascular endothelial growth factor A (VEGFA), phosphoinositide 3-kinase/protein kinase B (PI3K/AKT), Wingless/Int-1 (Wnt) /β-catenin, and mitogen-activated protein kinase (MAPK) pathways. Meanwhile, this review also looks at the challenges and opportunities that arise from harnessing natural compounds to influence TNBC, while outlining the prospective trajectory for future research in the field of NPs.

Managing pregnancy-associated breast cancer: A practical approach

Pregnancy-Associated Breast Cancer (PABC) is a rare but complex condition that presents both professional and ethical challenges. Diagnosis is often delayed due to breast changes associated with pregnancy and puerperium, which can mask malignant findings. Management requires a multidisciplinary approach that carefully balances maternal and fetal risks. Chemotherapy is generally reserved for the second and third trimesters to avoid teratogenicity, with anthracyclines being the most well-studied and safest agents in this setting. Surgical decisions are influenced by factors such as cancer stage, gestational age, and the timing of potential radiation therapy. Notably, radiation therapy, endocrine therapy, and most targeted therapies are contraindicated during pregnancy due to potential harm to the fetus. Comprehensive care should include robust social and mental health support for the mother and her family to help navigate the physical and emotional challenges during this period.

Multidisciplinary Management of Pregnancy-Associated Breast Cancer

Breast cancer during pregnancy is uncommon; however, it is one of the most common malignancies affecting pregnant women. Pregnancy-associated breast cancer (PABC) is a complex entity characterized by unique risk factors, presentation, and pathology. Furthermore, although management generally aims to mirror that for nonpregnant patients, there are distinct aspects of oncologic care delivery specific to PABC. The focus is on optimizing maternal outcomes while maximizing maternal and fetal safety. A multidisciplinary approach is key, and the timing of various treatment modalities is critical. Postdelivery care and counseling are also imperative to address issues such as contraception, breastfeeding, and future fertility. In the present review, we discuss the current knowledge base and the diagnostic and treatment landscape for PABC, including recent literature and practice pattern updates.

Assessing the effects of prostate cancer therapies on cardiovascular health

Contemporary advances in prostate cancer treatments have markedly improved patient outcomes, yet concerns persist regarding the increased cardiovascular toxicity of prostate cancer treatments, which is multifaceted. Local therapies entail non-negligible cardiovascular risks. The effects of androgen deprivation therapy, which is pivotal in disease management, on cardiovascular health remains contentious, with gonadotropin-releasing hormone agonists and antagonists showing varying cardiovascular outcomes. Despite the ongoing controversy over the cardiovascular risks of gonadotropin-releasing hormone antagonists versus agonists, current evidence does not support favouring one over the other based solely on cardiovascular risk. Combination therapy with androgen receptor pathway inhibitors and androgen deprivation therapy shows additive cardiovascular risks, but robust comparative data are lacking. Chemotherapies such as docetaxel and cabazitaxel, along with emerging targeted therapies and radiopharmaceuticals, are associated with varied cardiovascular risks, necessitating personalized patient assessment. Clinicians should adhere to cardio-oncology guidelines when prescribing therapeutic agents, especially for patients with pre-existing cardiovascular conditions. Optimal monitoring and management strategies are essential to mitigate cardiovascular morbidity and mortality.

Stem Cell Transplantation for Ovarian Cancer Patient with Associated Myelodysplasia After Maintenance Therapy with Olaparib: A Case Report

Ovarian cancer remains a significant cause of morbidity and mortality in women worldwide. Olaparib, a poly ADP-ribose polymerase (PARP) inhibitor, has been shown in studies to increase the time that people with cancer do not get worse. However, reports have indicated rare adverse effects, like myelodysplastic syndrome (MDS). In this report, we highlight the case of a 42-year-old female patient who was diagnosed with ovarian endometrioid carcinoma, FIGO Stage IIB. Following surgery and chemotherapy, the patient commenced maintenance therapy with Olaparib. After two years, she experienced abnormal blood test results, which ultimately led to a diagnosis of myelodysplastic syndrome (MDS), confirmed through a bone marrow biopsy. Despite initial obstacles, the patient underwent stem cell transplantation as a treatment for MDS. After undergoing stem cell transplantation, the patient experienced a notable improvement in their condition. Upon reevaluation, the transplantation proved successful as it resolved the abnormalities related to MDS. Furthermore, the ovarian cancer status showed a positive response, with no signs of disease progression during the follow-up period. This particular case emphasizes the importance of being vigilant for uncommon adverse effects, such as MDS, in ovarian cancer patients undergoing Olaparib maintenance therapy. Early diagnosis and treatment, which may include stem cell transplantation, can lead to favorable results, not only in managing MDS but also in possibly slowing down the progression of ovarian cancer that is causing it. Additional research is necessary to understand the risk factors and the most effective management approaches for these complications in this specific group of patients.

ATP-Dependent Chromatin Remodeler CSB Couples DNA Repair Pathways to Transcription with Implications for Cockayne Syndrome and Cancer Therapy

Efficient DNA lesion repair is crucial for cell survival, especially within actively transcribed DNA regions that contain essential genetic information. Additionally, DNA breaks in regions of active transcription are prone to generating insertions and deletions, which are hallmark features of cancer genomes. Cockayne syndrome protein B (CSB) is the sole ATP-dependent chromatin remodeler that is essential for coupling DNA repair pathways with transcription, leading to more efficient DNA repair in regions of active transcription. CSB is best known for its essential function in transcription-coupled nucleotide excision repair (TC-NER), a process that rapidly removes helix-distorting DNA lesions that stall RNA polymerase II, such as those created by chemotherapeutic platinum compounds and UV irradiation. In addition to NER, CSB has also been reported to couple homologous recombination to transcription. Most recently, CSB has also been shown to couple single-strand DNA break repair to transcription. In this review, we will discuss the overlapping and distinct mechanisms by which CSB couples these different DNA repair pathways to transcription. We will also discuss how these CSB functions may account for Cockayne syndrome and the emerging roles of CSB as an innovative target for cancer therapy.

Multi-stage structure-based virtual screening approach combining 3D pharmacophore, docking and molecular dynamic simulation towards the identification of potential selective PARP-1 inhibitors

Presently, humanity is confronted with a range of diseases that have high death rates, especially those linked to cancerous growths. Several enzymes and proteins have been discovered as highly attractive targets for cancer treatment. The PARP family consists of 17 members and plays a crucial role in repairing DNA damage, which enables the survival of cancer cells. PARP-1 and, to a lesser extent, PARP-2 display above 90% activity in response to DNA damage, thereby distinguishing them apart from other members of the PARP family. Elevated levels of PARP-1 were observed in many types of tumor cells, such as breast, lung, ovarian, prostate, and melanomas. In an attempt to provide a future guide for developing selective inhibitors for PARP-1 over PARP-2 to minimize the resulting side effects from PARP-2 inhibitors, we constructed a structure-based virtual screening approach (SBVS). Firstly. A 3D pharmacophore was constructed based on the interaction of the selective inhibitor compound IV. After that, a database of nearly 450,000 phthalimide-containing inhibitors was screened through the validated pharmacophore, and 165 compounds were retrieved. The retrieved compounds were docked into the active site of PARP-1 where only 5 compounds MWGS-1-5 achieved a favorable docking score than the reference IV (-16.8 Kcal/mol). Redocking of the five compounds should have excellent selectivity for PARP-1 over PARP-2, especially compound MWGS-1. Further endorsement via molecular dynamics has proven higher affinity and selectivity for MWGS-1 towards PARP-1 over PARP-2, in which PARP-1- MWGS-1 and PARP-1- MWGS-1 achieved RMSD values of 1.42 and 2.8 Å, respectively.

Evaluation of therapy support through a standardized nursing consultation for patients undergoing oral tumor therapy in gynecological oncology within the prospective CAMPA initiative

PURPOSE

The increase of oral tumor therapies (OTT) poses new challenges in patient care. Within CAMPA (Care improvement for advanced or metastatic breast and ovarian cancer patients treated with PARP-inhibitors), additional nursing support for patients treated with PARP-inhibitors was developed.

METHODS

Additional nursing support (1 year) was evaluated in breast and gynecooncological cancer patients at an academic and a non-academic outreach center. From 02/22 to 02/24, quality of life, contacts, adherence, documentation of drug intake, hospitalization, and adverse events were evaluated, using CANKADO-ePRO and validated questionnaires reviewed by the Ethics Committee of Medical Faculty, LMU Munich. Satisfaction with care was recorded from 03/23 to 02/24. Supporting materials and interprofessional checklists were explored.

RESULTS

The collective (n = 50) included 41 patients with ovarian, 4 with fallopian tube and 5 with breast cancer. Adherence measured by continuous documentation of medication intake was high among patients (78.0%). Quality of life improved from 68.6% to 81.4%, strongly correlating with decreasing numbers of side effects (p = 0.003) (Spearman |ρ| = 0.93). Satisfaction with care was very high (4.97 out of 5 points). 94.6% agreed that nursing consultation was essential for therapy safety compared to the doctor's consultation alone (p < 0.05). The reduction in time and care effort was significant (p < 0.05), having its maximum within the first three months.

CONCLUSION

Standardized nursing consultation was highly appreciated with an important contribution to adherence and improvement in quality of life. Delegation of therapy management to nurses reduces time effort and increases their responsibility, improving interprofessional care at academic and non-academic institutions.

TRIAL REGISTRATION

Clinical Trials Registry, LMU university hospital, Germany, Healthcare research project, number: 21-0848.

Expert Consensus Recommendations on the Management of Treatment-emergent Adverse Events Among Men with Prostate Cancer Taking Poly-ADP Ribose Polymerase Inhibitor + Novel Hormonal Therapy Combination Therapy

BACKGROUND AND OBJECTIVE

Recent clinical trials have shown improvement in progression-free survival in men with metastatic prostate cancer (mPC) treated with combination poly-ADP ribose polymerase (PARP) inhibitors (PARPi) and novel hormonal therapy (NHT). Regulatory bodies in the USA, Canada, Europe, and Japan have recently approved this combination therapy for mPC. Common adverse events (AEs) include fatigue, nausea and vomiting, and anemia. Nuanced AE management guidance for these combinations is lacking. The panel objective was to develop expert consensus on AE management in patients with mPC treated with the combination PARPi + NHT.

METHODS

The RAND/University of California Los Angeles modified Delphi Panel method was used. AEs were defined using the Common Terminology Criteria for Adverse Events. Twelve experts (seven medical oncologists, one advanced practice registered nurse, three urologists, and one patient advocate) reviewed the relevant literature; independently rated initial AE management options for the agent suspected of causing the AE for 419 patient scenarios on a 1-9 scale; discussed areas of agreement (AoAs) and disagreement (AoDs) at a March 2023 meeting; and repeated these ratings following the meeting. Second-round ratings formed the basis of guidelines.

KEY FINDINGS AND LIMITATIONS

AoDs decreased from 41% to 21% between the first and second round ratings, with agreement on at least one management strategy for every AE. AoAs included the following: (1) continue therapy with symptomatic treatment for patients with mild AEs; (2) for moderate fatigue, recommend nonpharmacologic treatment, hold treatment temporarily, and restart at a reduced dose when symptoms resolve; (3) for severe nausea or any degree of vomiting where symptomatic treatment fails, hold treatment temporarily and restart at a reduced dose when symptoms resolve; and (4) for hemoglobin 7.1-8.0 g/dl and symptoms of anemia, hold treatment temporarily and restart at a reduced dose after red blood cell transfusion.

CONCLUSIONS AND CLINICAL IMPLICATIONS

This expert guidance can support management of AEs in patients with mPC receiving combination PARPi + NHT therapy.

PATIENT SUMMARY

A panel of experts developed guidelines for adverse event (AE) management in patients with metastatic prostate cancer treated with a combination of poly-ADP ribose polymerase inhibitors and novel hormonal therapy. For mild AEs, continuation of cancer therapy along with symptomatic treatment is recommended. For moderate or severe AEs, cancer therapy should be stopped temporarily and restarted at the same or a reduced dose when AE resolves.

First-In-Human Dose Finding Study of Venadaparib (IDX-1197), a Potent and Selective PARP Inhibitor, in Patients With Advanced Solid Tumors

BACKGROUND

Venadaparib, a novel poly (ADP-ribose) polymerase (PARP) inhibitor, has demonstrated high PARP-1/2 selectivity over other PARP family members and exhibited strong PARP-trapping activity, effectively inhibiting tumor growth in homologous recombination deficient (HRD) cancer in vitro and in vivo.

METHODS

This phase 1, dose-finding study evaluated the safety, tolerability, pharmacokinetics, pharmacodynamics and anticancer efficacy of venadaparib as monotherapy in patients with advanced solid tumors that progressed after standard-of-care therapy. The study employed a conventional 3+3 design, with doses ranging from 2 mg/d to 240 mg/d.

RESULTS

Among the 32 enrolled patients, the most common tumor types were breast (16 patients) and ovarian (12 patients) cancers. No dose-limiting toxicities (DLTs) were observed up to 240 mg/d. The most frequent grade 3 or 4 adverse events were anemia (50%), neutropenia (22%) and thrombocytopenia (6%). Tumor shrinkage by Response Evaluation Criteria in Solid Tumours (RECIST) was observed at doses ≥ 40 mg/d, regardless of BRCA mutation status.Two partial responses out of four ovarian cancer patients receiving venadaparib ≥ 40 mg/d were reported. Clinical benefit, defined as stable disease or partial response, was observed at the lowest tested dose. Venadaparib exhibited ≥ 90% PAR inhibitory effect in pharmacodynamic analysis from 10 mg/d based on tumor samples. The recommended phase 2 dose (RP2D) was defined as 160 mg once daily.

CONCLUSIONS

Further studies are warranted to explore efficacy and safety of venadaparib in other tumor types and in combination with various agents, as well as to explore relevant biomarkers. (ClinicalTrials.gov ID: NCT03317743).

Incidence and Risk of Thromboembolic and Cardiovascular Adverse Events with PARP Inhibitor Treatment in Patients with Metastatic Castration-resistant Prostate Cancer: A Systematic Review and Safety Meta-analysis

Background and objective

PARP inhibitor (PARPi) treatment is an effective option for patients with metastatic castration-resistant prostate cancer (mCRPC). There are few data on the cardiovascular and thromboembolic safety of these agents in mCRPC, as cardiovascular and thromboembolic adverse events (AEs) are uncommon. Our aim was to analyze the incidence and risk of major adverse cardiovascular events (MACEs), thromboembolic events, and hypertension with PARPi therapy in mCRPC.

Methods

We conducted a systematic review and meta-analysis in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. We systematically searched the PubMed, EMBASE, and Cochrane databases and the American Society of Clinical Oncology and European Society of Medical Oncology meeting abstracts for clinical trials on PARPi use in mCRPC up to March 31, 2024. We analyzed the pooled incidence of all-grade and high-grade MACEs, thromboembolic events, and hypertension, and calculated risk ratios (RRs) for PARPi versus non-PARPi treatment.

Key findings and limitations

We included 11 phase 2 or 3 trials in our meta-analysis. Hypertension was the most common AE for both any-grade (17.2%) and high-grade (9.3%) events. In comparison to other treatments, PARPi was associated with significantly higher risk of high-grade MACEs (RR 2.03; p = 0.03) and thromboembolic events (RR 2.15; p = 0.002), especially venous thromboembolism (VTE; RR 2.13; p = 0.004) and pulmonary embolism (RR 3.60; p = 0.001). The risk of hypertension, any-grade MACEs, and thromboembolic AEs was not significantly higher, apart from VTE (RR 2.17; p = 0.01).

Conclusions and clinical implications

There is higher risk of high-grade cardiovascular and thromboembolic toxicity with PARPi use in comparison to other treatments in mCRPC, although these toxicities are rare. Clinicians should be aware of this risk, especially in a population that often has comorbidities and concomitant treatments, for correct monitoring and management of these AEs.

Patient summary

Drugs called PARP inhibitors are very effective in the treatment of metastatic prostate cancer that does not respond to hormone treatment. However, their use is associated with some cardiovascular adverse events, although these are rare. Our study shows that these events seem to be more frequent with PARP inhibitors than with other treatments, especially for severe grades. Doctors and patients should be aware of this risk to help in preventing, recognizing, and managing the occurrence of these rare complications.

Combination strategies with PARP inhibitors in BRCA-mutated triple-negative breast cancer: overcoming resistance mechanisms

Triple-negative breast cancer (TNBC) is a particularly aggressive breast cancer subtype, characterised by a higher incidence in younger women, rapid metastasis, and a generally poor prognosis. Patients with TNBC and BRCA mutations face additional therapeutic challenges due to the cancer's intrinsic resistance to conventional therapies. Poly (ADP-ribose) polymerase inhibitors (PARPis) have emerged as a promising targeted treatment for BRCA-mutated TNBC, exploiting vulnerabilities in the homologous recombination repair (HRR) pathway. However, despite initial success, the efficacy of PARPis is often compromised by the development of resistance mechanisms, including HRR restoration, stabilisation of replication forks, reduced PARP1 trapping, and drug efflux. This review explores latest breakthroughs in overcoming PARPi resistance through combination therapies. These strategies include the integration of PARPis with chemotherapy, immunotherapy, antibody-drug conjugates, and PI3K/AKT pathway inhibitors. These combinations aim to enhance the therapeutic efficacy of PARPis by targeting multiple cancer progression pathways. The review also discusses the evolving role of PARPis within the broader treatment paradigm for BRCA-mutated TNBC, emphasising the need for ongoing research and clinical trials to optimise combination strategies. By tackling the challenges associated with PARPi resistance and exploring novel combination therapies, this review sheds light on the future possibilities for improving outcomes for patients with BRCA-mutated TNBC.

Incidence and risk of endocrine and metabolic abnormalities linked to PARP inhibitors in solid tumors: a meta-analysis

BACKGROUND

Poly (ADP-ribose) polymerase inhibitors (PARPi) serve as crucial therapeutic agents in solid tumor treatment. Preclinical investigations suggest a potential protective function of PARPi against endocrine and metabolic impairments. Nevertheless, the existing body of evidence remains inconclusive on this aspect.

PURPOSE

Our aim was to evaluate the potential impact of PARPi on endocrine and metabolic disruptions in clinical trials.

DATA SOURCES

We conducted a comprehensive search across the Medline, EMBASE, PubMed, and Web of Science databases, along with the ClinicalTrials.gov registry.

STUDY SELECTION

Phase II/III randomized controlled trials (RCTs) investigating the effects of PARPi in metabolic and endocrine processes were selected for inclusion in patients with solid tumors.

DATA EXTRACTION

The primary outcomes of interest encompassed metabolic and endocrine dysfunctions.

DATA SYNTHESIS

A total of 26 trials (n = 9,590 patients) were included in our meta-analysis. Niraparib demonstrated an increased risk of any-grade hyperglycemia (OR = 2.15, 95% CI 1.28-3.62), with patients receiving PARPi for metastatic pancreatic cancer showing a higher susceptibility to any-grade hyperglycemia (OR = 1.78, 95% CI 1.04-3.04). Conversely, rucaparib exhibited a potential ameliorative effect on hyperglycemia (OR = 0.54, 95% CI 0.30-0.97). No statistically significant disparities were observed for other outcomes associated with PARPi utilization.

LIMITATIONS

Among these RCTs included, 50% were assessed as low qualities due to high risk of bias.

CONCLUSIONS

Our meta-analysis demonstrated that PARPi may exert adverse effects on endocrine and metabolic pathways. Close monitoring of hyperglycemia is recommended for patients undergoing niraparib therapy, especially those with pancreatic cancer.

TRIAL REGISTRATION

This meta-Analysis was prospectively registered in the PROSPERO database with ID CRD42023457959.

A comprehensive comparison of PARP inhibitors as maintenance therapy in platinum-sensitive recurrent ovarian cancer: a systematic review and network meta-analysis

BACKGROUND

PARP inhibitors (PARPis) have shown promising effectiveness for ovarian cancer. This network meta-analysis (PROSPERO registration number CRD42024503390) comprehensively evaluated the effectiveness and safety of PARPis in platinum-sensitive recurrent ovarian cancer (PSROC).

METHODS

Articles published before January 6, 2024 were obtained from electronic databases. The study assessed and compared survival outcomes including overall survival (OS), progression-free survival (PFS), second progression-free survival (PFS2), time to first subsequent treatment (TFST), time to second subsequent treatment (TSST), and chemotherapy-free interval (CFI). Additionally, safety outcomes were investigated, specifically focusing on grade 3-4 treatment-emergent adverse effects (TEAEs). The evaluation of OS and PFS was also conducted based on the BRCA and HRD (homologous recombination deficiency) statuses.

RESULTS

Six randomized controlled trials were examined and the four PARPis (olaparib, niraparib, rucaparib and fuluzolparib) have been found to significantly increase the PFS in entire population as well as in subgroups of HRD and BRCAm (BRCA mutation). Only olaparib demonstrated a substantial improvement in OS compared to placebo in entire population (hazard ratio [HR] 0.73; 95% confidence interval [CI] 0.60-0.90), as well as in the subgroup of BRCAm. All analyzed PARPis had significant efficacy in prolonging PFS2, TFST, TSST and CFI. For safety concerns, PARPis could significantly increase incidence of TEAEs (grade3-4), while olaparib had least haematological TEAEs (grade3-4) events compared to other PARPis.

CONCLUSION

All included PARPis showed various degrees of benefit in survival outcomes and safety profile was acceptable for PSROC patients. Among them olaparib had the best performance in both efficacy and safety.

A post-marketing pharmacovigilance study of triazole antifungals: adverse event data mining and analysis based on the FDA adverse event reporting system database

Background

To explore and analyze post-marketing adverse drug event (ADE) signals for voriconazole, posaconazole, and isavuconazole, and to compare the safety differences among the three drugs, aiming to provide insights for rational clinical use.

Methods

Using the Open Vigil 2.1 online tool, extract adverse drug event (ADE) report data for voriconazole, posaconazole, and isavuconazole from the U.S. Food and Drug Administration's Adverse Event Reporting System (FAERS) database from the time the drugs were marketed up to the third quarter of 2023. Employ the Reporting Odds Ratio (ROR) and Proportional Reporting Ratio (PRR) methods for data mining. Filter out ADE signals detected by both the ROR and PRR methods, and categorize these ADE signals by System Organ Class (SOC) according to the Medical Dictionary for Regulatory Activities (MedDRA 26.0).

Results

A total of 8,898 ADE reports with voriconazole as the primary suspect drug were retrieved, 1,948 for posaconazole, and 944 for isavuconazole. From the basic analysis of the adverse event reports, male patients (50.31%) outnumber female patients (32.11%). In terms of age, the majority of patients are over 45 years old (52.72%). The reports primarily come from the United States, Japan, France, China, and other countries. A total of 607 ADE signals were identified, with 402 for voriconazole, 159 for posaconazole, and 46 for isavuconazole. Voriconazole ADEs primarily involved the following SOCs: Investigations (9.45%), Eye Disorders (8.46%), and Nervous System Disorders (7.21%); Posaconazole ADEs primarily involved the following SOCs: Investigations (13.84%), General Disorders and Administration Site Conditions (11.95%), and Nervous System Disorders (6.29%); Isavuconazole ADEs primarily involved the following SOCs: General Disorders and Administration Site Conditions (15.22%), Hepatobiliary Disorders (10.87%), and Blood and Lymphatic System Disorders (10.87%).

Conclusion

Voriconazole, posaconazole, and isavuconazole all potentially pose safety risks related to hepatobiliary disorders and cardiac disorders. Additionally, voriconazole carries a higher safety risk for eye disorders and nervous system disorders. Newly discovered ADE signals not mentioned in the drug package inserts include voriconazole-induced rhabdomyolysis, posaconazole-induced peripheral neuropathy, and isavuconazole-induced visual impairment and mental confusion. These findings are significant for guiding rational clinical use of these medications.

PARP inhibitor-based treatment in metastatic, castration-resistant prostate cancer (mCRPC): A systematic review and meta-analysis

Background

We present a systematic review and meta-analysis of randomized clinical trials (RCTs) with PARPi either as monotherapy or in combination with an androgen receptor-targeted agent (ARTA) in first- and second-line settings.

Methods

Primary endpoints are radiographic progression free survival (rPFS) and overall survival (OS) in patients with mCRPC and either unselected, homologous recombination repair wild-type (HRR-), homologous recombination repair mutated (HRR+) or with BRCA1, BRCA2, or ATM mutation. The effect of PARPi + ARTA in the second-line setting is also explored. Safety is a secondary end-point.

Results

A total of five phase III (first line: MAGNITUDE, PROpel, TALAPRO-2; second line: PROfound, TRITON3) and two phase II RCTs (second line: NCT01972217, NCT01576172) were selected. In the first-line setting, rPFS was significantly improved in PARPi + ARTA arm in all comers (HR 0.70, p < 0.00001), HRR- (HR 0.76, p = 0.005), HRR+ (HR 0.57, p = 0.0003), and BRCA1/2-mutated patients (HR: 0.33, p < 0.00001). OS was improved in the population with HRR+ status (HR 0.76, p = 0.02) but not statistically significant in BRCA1/2-mutated patients (HR 0.57, 95% CI 0.30-1.08, p = 0.08). In the second line, PARPi improves rPFS (HR for BRCA2 0.31, p = 0.002) and OS (HR for BRCA1/2 0.71, p = 0.01) only in such patients. In this setting, no advantage was reported by adding a PARPi to an ARTA. The arm with PARPi either as monotherapy or in combination with ARTA showed a significantly higher toxicity profile.

Conclusions

PARPi-based therapy represents a compelling treatment option for HRR+ mCRPC, mainly BRCA1/2-mutated patients. However, further biomarker analysis are needed in order to identify other responsive patients across the different disease settings.

Innovative Approaches for Molecular Targeted Therapy of Breast Cancer: Interfering with Various Pathway Signaling

Breast cancer encompasses a diverse array of conditions classified as hormone receptor-positive, human epidermal growth factor receptor 2-positive, and triple-negative breast cancer subtypes, dictating treatment approaches. The therapeutic strategies commonly involve addressing estrogen receptors (ER) and HER2, which have exhibited efficacy in managing cancer. Nevertheless, the prevalence of resistance to these therapies, whether inherent or acquired, persists despite the introduction of novel treatment modalities. Progress in comprehending the biology of tumors has facilitated the identification of fresh targets, such as inhibitors targeting different pathways like phosphoinositide 3-kinase/mammalian target of rapamycin (PI3K/mTOR), cell-cycle regulation, heat shock protein, and epigenetic pathways, demonstrating encouraging outcomes in clinical experiments. For example, the mTOR inhibitor everolimus has been sanctioned for ER+ breast cancer and resistance to aromatase inhibitors in the advanced or metastatic phase. Triple-negative breast cancer, characterized by the absence of estrogen receptors, progesterone receptors, and HER2, currently lacks established targeted therapies. While poly (ADP-ribose) polymerase inhibitors exhibit effectiveness in BRCA-related cancers, their efficiency in addressing triple-negative breast cancer residues is uncertain. This paper furnishes a comprehensive outline of the principal targeted therapies presently employed or under exploration for breast cancer treatment within the three clinical subsets.

Potential Synergistic Effect between Niraparib and Statins in Ovarian Cancer Clinical Trials

SIGNIFICANCE

The presented retrospective analysis suggests, to the best of our knowledge for the first time, a potential significant interaction between statins and niraparib in clinical settings. Nevertheless, further investigations are required to gain a better understanding of the potential clinical benefit.

Hematopoietic adverse events associated with PARP inhibitors: A FAERS database study

OBJECTIVES

Analyze hematopoietic ADR signals of PARP inhibitors (Olaparib, Niraparib, Rucaparib, Talazoparib) using FAERS data to inform clinical practice.

METHODS

Extracted ASCII data for these drugs from Q1 2019 to Q2 2024. Employed SMQ and PT for standardization. Screened ADR signals via ROR, PRR, and MHRA method, comparing SMQ ratios.

RESULTS

Hematopoietic ADRs peaked within 30 days post-treatment, with cytopenia and leukopenia most prevalent. Niraparib showed the highest adverse event count and signal intensity. Olaparib and Talazoparib also indicated strong hematotoxicity.

CONCLUSION

PARP inhibitors vary in ADR incidence and duration, necessitating personalized treatment plans for optimized safety and rational use.

BRCA and Beyond: Impact on Therapeutic Choices Across Cancer

BACKGROUND

Identifying patients with gBRCAm is crucial to facilitate screening strategies, preventive measures and the usage of targeted therapeutics in their management. This review examines the evidence for the latest predictive and therapeutic approaches in BRCA-associated cancers.

CLINICAL DESCRIPTION

Data supports the use of adjuvant olaparib in patients with gBRCAm high-risk HER2-negative breast cancer. In advanced gBRCAm HER2-negative breast cancer, the PARPis talazoparib and olaparib have demonstrated benefit over standard chemotherapy. In ovarian cancer, olaparib, niraparib or rucaparib can be used as monotherapy in frontline maintenance. Olaparib and bevacizumab as a combination can also be used as frontline maintenance. In the relapsed platinum-sensitive setting, olaparib, niraparib and rucaparib are effective maintenance options in BRCAm patients who are PARPi naive. Both olaparib and rucaparib are effective options in BRCAm metastatic castrate-resistant prostate cancer (mCRPC). Evidence also exists for the benefit of PARPi combinations in mCRPC. In metastatic pancreatic cancer, olaparib can be used in gBRCAm patients who are responding to platinum chemotherapy. However, there may be a development of PARPi resistance. Understanding the pathophysiology that contributes to such resistance may allow the development of novel therapeutics. Combination therapy appears to have promising results in emerging trials. Seeking avenues for subsidised genetic testing can reduce the total costs of cancer management, leading to improve detection rates.

CONCLUSION

Identifying breast, ovarian, pancreatic and prostate cancer patients with gBRCAm plays a crucial predictive role in selecting those who will benefit significantly from PARPi therapy. The use of PARPi in gBRCAm HBOC-related cancers has resulted in significant survival benefits. Beyond BRCA1/2, HRR gene assessment and the consideration of other cancer predisposition syndromes may allow more patients to be eligible for and benefit from targeted therapies.

Mitochondria-targeted oligomeric α-synuclein induces TOM40 degradation and mitochondrial dysfunction in Parkinson's disease and parkinsonism-dementia of Guam

Mitochondrial dysfunction is a central aspect of Parkinson's disease (PD) pathology, yet the underlying mechanisms are not fully understood. This study investigates the link between α-Synuclein (α-Syn) pathology and the loss of translocase of the outer mitochondrial membrane 40 (TOM40), unraveling its implications for mitochondrial dysfunctions in neurons. We discovered that TOM40 protein depletion occurs in the brains of patients with Guam Parkinsonism-Dementia (Guam PD) and cultured neurons expressing α-Syn proteinopathy, notably, without corresponding changes in TOM40 mRNA levels. Cultured neurons expressing α-Syn mutants, with or without a mitochondria-targeting signal (MTS) underscores the role of α-Syn's mitochondrial localization in inducing TOM40 degradation. PDe-related etiological factors, such as 6-hydroxydopamine or ROS/metal ions stress, which promotes α-Syn oligomerization, exacerbate TOM40 depletion in PD patient-derived cells with SNCA gene triplication. Although α-Syn interacts with both TOM40 and TOM20 in the outer mitochondrial membrane, degradation is selective for TOM40, which occurs via the ubiquitin-proteasome system (UPS) pathway. Our comprehensive analyses using Seahorse technology, mitochondrial DNA sequencing, and damage assessments, demonstrate that mutant α-Syn-induced TOM40 loss results in mitochondrial dysfunction, characterized by reduced membrane potential, accumulation of mtDNA damage, deletion/insertion mutations, and altered oxygen consumption rates. Notably, ectopic supplementation of TOM40 or reducing pathological forms of α-Syn using ADP-ribosylation inhibitors ameliorate these mitochondrial defects, suggesting potential therapeutic avenues. In conclusion, our findings provide crucial mechanistic insights into how α-Syn accumulation leads to TOM40 degradation and mitochondrial dysfunction, offering insights for targeted interventions to alleviate mitochondrial defects in PD.

Discovery of Pyrazolo[1,5,4-de]quinoxalin-2(3H)-one Derivatives as Highly Potent and Selective PARP1 Inhibitors

Poly-ADP-ribose-polymerase 1/2 (PARP1/2) inhibitors have been approved for cancers with homologous recombination deficiency (HRD). However, their narrow therapeutic indexes largely due to hematologic toxicities have limited their clinical usefulness. Developing selective PARP1 inhibitors has emerged as an attractive strategy to achieve equivalent antitumor activity while alleviating the hematological toxicity caused by PARP2 inhibition. Herein, we report the discovery of pyrazolo[1,5,4-de]quinoxalin-2(3H)-one 30 as a novel selective PARP1 inhibitor. 30 formed tighter PARP1-DNA trapping than AZD9574, leading to better potency in inhibiting cancer cell proliferation. 30 achieved tumor regression in the BRCA1-mutated MDA-MB-436 xenograft model and showed synergistic efficacy in combination with carboplatin in the SUM149PT xenograft model. In the rat hematological toxicity study, 30 exhibited minimal impact on hematological parameters at 25 mg/kg, while AZD5305 at 1 mg/kg caused 56.5% reduction of reticulocyte. Taken together, we discovered compound 30 with a therapeutic index superior to that of PARP1 inhibitors AZD5305 and AZD9574 in the preclinical setting.

The complex universe of inactive PARP1

Poly(ADP-ribose) polymerase 1 (PARP1) is a crucial member of the PARP family, which modifies targets through ADP-ribosylation and plays key roles in a variety of biological processes. PARP inhibitors (PARPis) hinder ADP-ribosylation and lead to the retention of PARP1 at the DNA lesion (also known as trapping), which underlies their toxicity. However, inhibitors and mutations that make PARP1 inactive do not necessarily correlate with trapping potency, challenging the current understanding of inactivation-caused trapping. Recent studies on mouse models indicate that both trapping and non-trapping inactivating mutations of PARP1 lead to embryonic lethality, suggesting the unexpected toxicity of the current inhibition strategy. The allosteric model, complicated automodification, and various biological functions of PARP1 all contribute to the complexity of PARP1 inactivation.

The PARP inhibitor rucaparib blocks SARS-CoV-2 virus binding to cells and the immune reaction in models of COVID-19

BACKGROUND AND PURPOSE

To date, there are limited options for severe Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2 virus. As ADP-ribosylation events are involved in regulating the life cycle of coronaviruses and the inflammatory reactions of the host; we have, here, assessed the repurposing of registered PARP inhibitors for the treatment of COVID-19.

EXPERIMENTAL APPROACH

The effects of PARP inhibitors on virus uptake were assessed in cell-based experiments using multiple variants of SARS-CoV-2. The binding of rucaparib to spike protein was tested by molecular modelling and microcalorimetry. The anti-inflammatory properties of rucaparib were demonstrated in cell-based models upon challenging with recombinant spike protein or SARS-CoV-2 RNA vaccine.

KEY RESULTS

We detected high levels of oxidative stress and strong PARylation in all cell types in the lungs of COVID-19 patients, both of which negatively correlated with lymphocytopaenia. Interestingly, rucaparib, unlike other tested PARP inhibitors, reduced the SARS-CoV-2 infection rate through binding to the conserved 493-498 amino acid region located in the spike-ACE2 interface in the spike protein and prevented viruses from binding to ACE2. In addition, the spike protein and viral RNA-induced overexpression of cytokines was down-regulated by the inhibition of PARP1 by rucaparib at pharmacologically relevant concentrations.

CONCLUSION AND IMPLICATIONS

These results point towards repurposing rucaparib for treating inflammatory responses in COVID-19.

Therapy-related myelodysplastic syndromes and acute myeloid leukemia

Progress always comes at a price: the field of oncology has seen unprecedented progress in treatment options recently for many solid and hematologic cancers. Unfortunately, these long-term survivors of prior cancer and cytotoxic therapy exposure are at higher risk of therapy-related myelodysplastic syndromes/acute myeloid leukemia (t-MDS/AML.) T-MDS/AML is a myeloid malignancy which occur after exposure to chemotherapy or radiation therapy for unrelated malignancy. T-MDS/AML is associated with adverse cytogenomic features and poor prognosis. While advances in the field of clonal hematopoiesis and germline variants has unraveled the molecular underpinnings of t-MDS/AML, we have miles to go in terms of t-MDS/AML directed therapy and improvement in outcomes. In this review, we discuss the epidemiology of t-MDS/AML, clinical and biological insights, evolution of t-MDS/AML and available treatment options.

ATR inhibition increases reliance on PARP-mediated DNA repair revealing an improved therapeutic strategy for cervical cancer

OBJECTIVE

Cervical cancer results from persistent infection with high-risk human papillomavirus (HR-HPV) and the expression of E6 and E7 oncoproteins. E6 and E7 compromise the activity of p53 and Rb, the G1-S cell cycle checkpoint, and ATM-mediated DNA damage repair (DDR), which in turn increases reliance on ATR- and PARP-mediated DDR at the G2 cell cycle checkpoint. This study aimed to determine the effects of an ATR inhibitor (ATRi, AZD6738) and a PARP-inhibitor (PARPi, AZD2281) on HR-HPV+ cervical cancer cell lines.

METHODS

The effects of ATRi and PARPi, alone and in combination, on metabolic viability, cell cycle arrest, apoptosis, and DDR pathways in cervical cancer cell lines were evaluated in vitro, and the in vivo tumor response was evaluated using a xenograft model.

RESULTS

Cervical cancer cells were sensitive to ATRi and PARPi monotherapy. The combination therapy was only synergistic in reducing metabolic viability when exposed to ATRi first, followed by PARPi, owing to ATRi-mediated upregulation of PARP expression. Combination of ATRi and PARPi induced G2 cell cycle arrest and apoptosis. PARPi induced DNA damage and γH2AX phosphorylation, which was further increased by ATRi treatment. However, PARPi-induced Rad51 foci formation was reduced by ATRi treatment, suggesting the inhibition of homologous recombination repair. ATRi significantly reduced cervical cancer xenograft tumor growth and was not affected by simultaneous PARPi treatment at the doses studied.

CONCLUSIONS

Our findings show that ATRi increased reliance on PARP for metabolic viability, the combination of ATRi and PARPi induced synthetic lethality in cervical cancer in vitro, and reduced tumor burden in vivo.

PARP inhibitors in gliomas: Mechanisms of action, current trends and future perspectives

Gliomas are the most common primary malignant brain tumours in adults. Despite decades of research into novel therapeutic approaches, the prognosis remains poor. PARP1-2 are critical for DNA repair, cell survival and genomic stability and PARP inhibition (PARPi) may be a promising therapeutic approach for gliomas. Inhibition of PARP activity leads to homologous recombination deficiency (HRD), which, in combination with DNA damage, results in cell death. This review summarises the current knowledge and future perspectives of PARPi in glioma. The available literature was reviewed using PubMed, recent major international oncology congresses were consulted, and ongoing clinical trials were searched using ClinicalTrials.gov. In translational research, PARPi have demonstrated a strong scientific rationale for their use in the treatment of glioma. They have been evaluated both alone and in combination with radiotherapy, temozolomide, anti-angiogenic agents, immunotherapy and other new drugs in newly diagnosed or recurrent glioma. Most studies were open-label, non-randomised, dose-escalation phase I-II trials. Early results show promising anti-tumour activity, and key challenges include identifying predictive biomarkers, elucidating synergistic effects in combination therapies, addressing the development of resistance, and managing hematological toxicity. In conclusion, early phase studies have shown promising anti-tumour activity of PARPi that should be confirmed in larger prospective and randomised trials. In addition, the development of novel PARPi with improved blood brain barrier (BBB) penetration and PARP inhibitor activity with new synergistic treatment combinations seems promising and needs to be further explored.

NAD+ depletion is central to placental dysfunction in an inflammatory subclass of preeclampsia

Preeclampsia (PE) is a hypertensive disorder of pregnancy and a major cause of maternal/perinatal adverse health outcomes with no effective therapeutic strategies. Our group previously identified distinct subclasses of PE, one of which exhibits heightened placental inflammation (inflammation-driven PE). In non-pregnant populations, chronic inflammation is associated with decreased levels of cellular NAD+, a vitamin B3 derivative involved in energy metabolism and mitochondrial function. Interestingly, specifically in placentas from women with inflammation-driven PE, we observed the increased activity of NAD+-consuming enzymes, decreased NAD+ content, decreased expression of mitochondrial proteins, and increased oxidative damage. HTR8 human trophoblasts likewise demonstrated increased NAD+-dependent ADP-ribosyltransferase (ART) activity, coupled with decreased mitochondrial respiration rates and invasive function under inflammatory conditions. Such adverse effects were attenuated by boosting cellular NAD+ levels with nicotinamide riboside (NR). Finally, in an LPS-induced rat model of inflammation-driven PE, NR administration (200 mg/kg/day) from gestational days 1-19 prevented maternal hypertension and fetal/placental growth restriction, improved placental mitochondrial function, and reduced inflammation and oxidative stress. This study demonstrates the critical role of NAD+ in maintaining placental function and identifies NAD+ boosting as a promising preventative strategy for PE.

Revolutionizing medicine: Harnessing plant-derived vesicles for therapy and drug transport

The emergence of extracellular vesicles (EVs), which are natural lipid bilayer membrane structures facilitating intercellular substance and information exchange, has sparked innovative approaches in drug development and carrier enhancement. Plant-derived EVs notably offer advantages including low preparation cost, low immunogenicity, flexible drug delivery, high stability, good tissue permeability, and high inherent medicinal value compared to their animal-derived counterparts. Despite these promising attributes, the research on plant-derived EVs remains fragmented and lacks comprehensive synthesis. This review aims to address this gap by summarizing the isolation methods, biological characteristics, and storage techniques of plant-derived EVs. Additionally, we explore the potential of plant-derived EVs as therapeutic agents and drug carriers for treating various diseases. Finally, we delineate the current impediments to plant-derived EV development and highlight future research directions. By providing a detailed overview, we hope to facilitate further research and application in this emerging field.

Application and research progress of synthetic lethality in the development of anticancer therapeutic drugs

With the tremendous success of the PARP inhibitor olaparib in clinical practice, synthetic lethality has become an important field for the discovery and development of anticancer drugs. More and more synthetic lethality targets have been discovered with the rapid development of biotechnology in recent years. Currently, many drug candidates that were designed and developed on the basis of the concept of synthetic lethality have entered clinical trials. Taking representative synthetic lethal targets Poly ADP-ribose polymerase 1 (PARP1), Werner syndrome helicase (WRN) and protein arginine methyltransferase 5 (PRMT5) as examples, this article briefly discusses the application and research progress of synthetic lethality in the development of anticancer drugs.

Aminomethylmorpholino Nucleosides as Novel Inhibitors of PARP1 and PARP2: Experimental and Molecular Modeling Analyses of Their Selectivity and Mechanism of Action

Poly(ADP-ribose) polymerases 1 and 2 (PARP1 and PARP2) play a key role in DNA repair. As major sensors of DNA damage, they are activated to produce poly(ADP-ribose). PARP1/PARP2 inhibitors have emerged as effective drugs for the treatment of cancers with BRCA deficiencies. Here, we explored aminomethylmorpholino and aminomethylmorpholino glycine nucleosides as inhibitors of PARP1 and PARP2, using different enzymatic assays. The compounds bearing thymine or 5-Br(I)-uracil bases displayed the highest inhibition potency, with all of them being more selective toward PARP1. Interaction of the inhibitors with the NAD+ binding cavity of PARP1 (PARP2) suggested by the mixed-type inhibition was demonstrated by molecular docking and the RoseTTAFold All-Atom AI-model. The best PARP1 inhibitors characterized by the inhibition constants in the range of 12-15 µM potentiate the cytotoxicity of hydrogen peroxide by displaying strong synergism. The inhibitors revealed no impact on PARP1/PARP2 affinity for DNA, while they reduced the dissociation rate of the enzyme-DNA complex upon the autopoly(ADP-ribosyl)ation reaction, thus providing evidence that their mechanism of action for PARP trapping is due primarily to catalytic inhibition. The most active compounds were shown to retain selectivity toward PARP1, despite the reduced inhibition potency in the presence of histone PARylation factor 1 (HPF1) capable of regulating PARP1/PARP2 catalytic activity and ADP-ribosylation reaction specificity. The inhibitors obtained seem to be promising for further research as potential drugs.

Chemoprevention strategies in hereditary breast and ovarian cancer syndromes

Hereditary breast and/or ovarian cancer syndromes are inherited disorders in which there is an increased risk of developing breast and/or ovarian cancer in the lifetime, usually at a younger age compared to the general population. Cancer prevention in these syndromes includes prophylactic surgeries, personalized surveillance programs and chemopreventive strategies. Chemoprevention exploits the use of certain drugs or other substances to help lower the risk of developing cancer. In this context, tamoxifen was the first agent considered for breast cancer prevention, followed by raloxifene and the third-generation aromatase inhibitors. On the other hand, the first and most widespread type of chemoprevention for ovarian cancer was combined hormonal contraceptive use. Although several strategies have been studied and showed promising results, only a few of these are currently applied in daily clinical practice. Side effects along with several psychological variables such as cancer perceived risk, worries and related distress, strongly influence women's decision on chemoprevention. The present review explores and summarizes the available evidence on breast and ovarian cancer chemoprevention approaches.

Bibliometric analysis of olaparib and pancreatic cancer from 2009 to 2022: A global perspective

BACKGROUND

Genetic screening for breast cancer gene 1 (BRCA)1/2 mutations can inform breast/ovarian/pancreatic cancer patients of suitable therapeutic interventions. Four to seven percent of pancreatic cancer patients have germline BRCA mutations. BRCA genes aid in DNA repair, especially homologous recombination, which impacts genomic stability and cancer cell growth. BRCA1 regulates the cell cycle, ubiquitination, and chromatin remodeling, whereas BRCA2 stimulates the immune response. They predict the efficacy of platinum chemotherapy or polymerase (PARP) inhibitors such as olaparib.

AIM

To determine the trends and future directions in the use of olaparib for pancreatic cancer treatment.

METHODS

To evaluate the trends in how olaparib works in pancreatic cancer, we performed a bibliometric analysis. One hundred and ninety-six related publications were accessed from the Web of Science Core Collection and were published between 2009 and 2022. The analytic parameters included publications, related citations, productive countries and institutes, influential authors, and keyword development.

RESULTS

This study visualizes and discusses the current research, including the present global trends and future directions in olaparib and pancreatic cancer. Overall, this study sheds light on optimizing the use of olaparib in pancreatic cancer treatment, offering valuable guidance for researchers in this field.

CONCLUSION

Our findings identified trends in olaparib and pancreatic cancer, with China and the USA leading and with global cooperation tightening. O'Reilly EM's team and Memorial Sloan-Kettering had the highest output. The Journal of Clinical Oncology was the most cited journal. More PARP inhibitors are emerging, and combination therapy is suggested for future therapeutic trends.

An update on small molecule compounds targeting synthetic lethality for cancer therapy

Targeting cancer-specific vulnerabilities through synthetic lethality (SL) is an emerging paradigm in precision oncology. A SL strategy based on PARP inhibitors has demonstrated clinical efficacy. Advances in DNA damage response (DDR) uncover novel SL gene pairs. Beyond BRCA-PARP, emerging SL targets like ATR, ATM, DNA-PK, CHK1, WEE1, CDK12, RAD51, and RAD52 show clinical promise. Selective and bioavailable small molecule inhibitors have been developed to induce SL, but optimization for potency, specificity, and drug-like properties remains challenging. This article illuminated recent progress in the field of medicinal chemistry centered on the rational design of agents capable of eliciting SL specifically in neoplastic cells. It is envisioned that innovative strategies harnessing SL for small molecule design may unlock novel prospects for targeted cancer therapeutics going forward.

Discovery of PARP1-Sparing Inhibitors for Protein ADP-Ribosylation

Poly-ADP-ribose polymerases (PARPs) that catalyze cellular ADP-ribosylation play important roles in human health. PARP inhibitors have found success in the clinic for cancer treatment. However, isoform-specific inhibitors are needed for improved safety. Here, we report the unexpected discovery of nicotinamide mimics that block non-PARP1-catalyzed ADP-ribosylation at micromolar concentrations. These PARP1-sparing PARP inhibitors represent first-in-class probes for ADP-ribosylation, shedding light on the selective inhibition of PARPs.

Carbamoylation at C-8 position of natural 3-arylcoumarin scaffold for the discovery of novel PARP-1 inhibitors with potent anticancer activity

Structural modification based on natural privileged scaffolds has proven to be an attractive approach to generate potential antitumor candidates with high potency and specific targeting. As a continuation of our efforts to identify potent PARP-1 inhibitors, natural 3-arylcoumarin scaffold was served as the starting point for the construction of novel structural unit for PARP-1 inhibition. Herein, a series of novel 8-carbamyl-3-arylcoumarin derivatives were designed and synthesized. The antiproliferative activities of target compounds against four BRCA-mutated cancer cells (SUM149PT, HCC1937, MDA-MB-436 and Capan-1) were evaluated. Among them, compound 9b exhibited excellent antiproliferative effects against SUM149PT, HCC1937 and Capan-1 cells with IC50 values of 0.62, 1.91 and 4.26 μM, respectively. Moreover, 9b could significantly inhibit the intracellular PARP-1/2 activity in SUM149PT cells with IC50 values of 2.53 nM and 6.45 nM, respectively. Further mechanism studies revealed that 9b could aggravate DNA double-strand breaks, increase ROS production, decrease mitochondrial membrane potential, arrest cell cycle at G2/M phase and ultimately induce apoptosis in SUM149PT cells. In addition, molecular docking study demonstrated that the binding mode of 9b with PARP-1 was similar to that of niraparib, forming multiple hydrogen bond interactions with the active site of PARP-1. Taken together, these findings suggest that 8-carbamyl-3-arylcoumarin scaffold could serve as an effective structural unit for PARP-1 inhibition and offer a valuable paradigm for the structural modification of natural products.

Resveratrol Inhibits Nucleosome Binding and Catalytic Activity of PARP1

The natural polyphenol resveratrol is a biologically active compound that interacts with DNA and affects the activity of some nuclear enzymes. Its effect on the interaction between nucleosomes and poly(ADP-ribose) polymerase-1 (PARP1) and on the catalytic activity of PARP1 was studied using Western blotting, spectrophotometry, electrophoretic mobility shift assay, and single particle Förster resonance energy transfer microscopy. Resveratrol inhibited PARP1 activity at micro- and sub-micromolar concentrations, but the inhibitory effect decreased at higher concentrations due to the aggregation of the polyphenol. The inhibition of PARP1 by resveratrol was accompanied by its binding to the enzyme catalytic center and a subsequent decrease in PARP1 affinity to nucleosomal DNA. Concurrent binding of talazoparib to the substrate binding pocket of PARP1, which occurs in the presence of resveratrol, restores the interaction of PARP1 with nucleosomes, suggesting that the binding sites of resveratrol and talazoparib overlap. The data suggest that resveratrol can be classified as a natural inhibitor of PARP1.