Apurinic/apyrimidinic endonuclease 1 has major impact in prevention of suicidal covalent DNA-protein crosslink with apurinic/apyrimidinic site in cellular extracts.

DNA-protein crosslinks (DPC) are common DNA lesions induced by various external and endogenous agents. One of the sources of DPC is the apurinic/apyrimidinic site (AP site) and proteins interacting with it. Some proteins possessing AP lyase activity form covalent complexes with AP site-containing DNA without borohydride reduction (suicidal crosslinks). We have shown earlier that tyrosyl-DNA phosphodiesterase 1 (TDP1) but not AP endonuclease 1 (APE1) is able to remove intact OGG1 from protein-DNA adducts, whereas APE1 is able to prevent the formation of DPC by hydrolyzing the AP site. Here we demonstrate that TDP1 can remove intact PARP2 but not XRCC1 from covalent enzyme-DNA adducts with AP-DNA formed in the absence of APE1. We also analyzed an impact of APE1 and TDP1 on the efficiency of DPC formation in APE1-/- or TDP1-/- cell extracts. Our data revealed that APE1 depletion leads to increased levels of PARP1-DNA crosslinks, whereas TDP1 deficiency has little effect on DPC formation.

Low testing rates and high BRCA prevalence: Poly (ADP-ribose) polymerase inhibitor use in Middle East BRCA/homologous recombination deficiency-positive cancer patients.

BACKGROUND: Poly (ADP-ribose) polymerase inhibitors (PARPis) are approved as first-line therapies for breast cancer gene (BRCA)-positive, human epidermal growth factor receptor 2-negative locally advanced or metastatic breast cancer. They are also effective for new and recurrent ovarian cancers that are BRCA- or homologous recombination deficiency (HRD)-positive. However, data on these mutations and PARPi use in the Middle East are limited. AIM: To assess BRCA/HRD prevalence and PARPi use in patients in the Middle East with breast/ovarian cancer. METHODS: This was a single-center retrospective study of 57 of 472 breast cancer patients tested for BRCA mutations, and 25 of 65 ovarian cancer patients tested for HRD. These adult patients participated in at least four visits to the oncology service at our center between August 2021 and May 2023. Data were summarized using descriptive statistics and compared using counts and percentages. Response to treatment was assessed using Response Evaluation Criteria in Solid Tumors criteria. RESULTS: Among the 472 breast cancer patients, 12.1% underwent BRCA testing, and 38.5% of 65 ovarian cancer patients received HRD testing. Pathogenic mutations were found in 25.6% of the tested patients: 26.3% breast cancers had germline BRCA (gBRCA) mutations and 24.0% ovarian cancers showed HRD. Notably, 40.0% of gBRCA-positive breast cancers and 66.0% of HRD-positive ovarian cancers were Middle Eastern and Asian patients, respectively. PARPi treatment was used in 5 (33.3%) gBRCA-positive breast cancer patients as first-line therapy (n = 1; 7-months progression-free), for maintenance (n = 2; > 15-months progression-free), or at later stages due to compliance issues (n = 2). Four patients (66.6%) with HRD-positive ovarian cancer received PARPi and all remained progression-free. CONCLUSION: Lower testing rates but higher BRCA mutations in breast cancer were found. Ethnicity reflected United Arab Emirates demographics, with breast cancer in Middle Eastern and ovarian cancer in Asian patients.

Poly (ADP-ribose): A double-edged sword governing cancer cell survival and death.

Poly (ADP-ribose) (PAR), a polymer of ADP-ribose, is synthesized by PAR polymerase and is crucial for the survival of cancer cells due to its vital functions in DNA repair and post-translational modifications. Beyond its supportive role, PAR also triggers cancer cell death by excessive accumulation of PAR leading to an energy crisis and parthanatos. This phenomenon underscores the potential of targeting PAR regulation as a novel anticancer strategy, and the rationale would present an engaging topic in the field of anticancer research. Therefore, this editorial provides an overview of the mechanisms determining cancer cell fate, emphasizing the central role of PAR. It further introduces promising methods for modulating PAR concentrations that may pave the way for innovative anticancer therapies.

Proteasome and PARP1 dual-target inhibitor for multiple myeloma: Fluzoparib.

One of the current mainstream treatments for multiple myeloma (MM) is chemotherapy. However, due to the high clonal heterogeneity and genomic complexity of MM, single-target drugs have limited efficacy and are prone to drug resistance. Therefore, there is an urgent need to develop multi-target drugs against MM. We screened drugs that simultaneously inhibit poly(ADP-ribose) polymerase 1 (PARP1) and 20S proteasome through computer-aided drug discovery (CADD) techniques, and explored the binding mode and dynamic stability of selected inhibitor to proteasome through Molecular biology (MD) simulation method. Thus, the dual-target inhibition effect of fluzoparib was proposed for the first time, and the ability of dual-target inhibition and tumor killing was explored at the enzyme, cell and animal level, respectively. This provides a theoretical and experimental basis for exploring multi-target inhibitory drugs for cancers.

Activity of DNA Repair Systems in the Cells of Long-Lived Rodents and Bats.

Damages of various origin accumulated in the genomic DNA can lead to the breach of genome stability, and are considered to be one of the main factors involved in cellular senescence. DNA repair systems in mammalian cells ensure effective damage removal and repair of the genome structure, therefore, activity of these systems is expected to be correlated with high maximum lifespan observed in the long-lived mammals. This review discusses current results of the studies focused on determination of the DNA repair system activity and investigation of the properties of its key regulatory proteins in the cells of long-lived rodents and bats. Based on the works discussed in the review, it could be concluded that the long-lived rodents and bats in general demonstrate high efficiency in functioning and regulation of DNA repair systems. Nevertheless, a number of questions around the study of DNA repair in the cells of long-lived rodents and bats remain poorly understood, answers to which could open up new avenues for further research.

NAD+ overconsumption by poly (ADP-ribose) polymerase (PARP) under oxidative stress induces cytoskeletal disruption in vascular endothelial cell.

Vascular endothelial cytoskeletal disruption leads to increased vascular permeability and is involved in the pathogenesis and progression of various diseases. Oxidative stress can increase vascular permeability by weakening endothelial cell-to-cell junctions and decrease intracellular nicotinamide adenine dinucleotide (NAD+) levels. However, it remains unclear how intracellular NAD+ variations caused by oxidative stress alter the vascular endothelial cytoskeletal organization. In this study, we demonstrated that oxidative stress activates poly (ADP-ribose [ADPr]) polymerase (PARP), which consume large amounts of intracellular NAD+, leading to cytoskeletal disruption in vascular endothelial cells. We found that hydrogen peroxide (H2O2) could transiently disrupt the cytoskeleton and reduce intracellular total NAD levels in human umbilical vein endothelial cells (HUVECs). H2O2 stimulation led to rapid increase in ADPr protein levels in HUVECs. Pharmaceutical PARP inhibition counteracted H2O2-induced total NAD depletion and cytoskeletal disruption, suggesting that NAD+ consumption by PARP induced cytoskeletal disruption. Additionally, supplementation with nicotinamide mononucleotide (NMN), the NAD+ precursor, prevented both intracellular total NAD depletion and cytoskeletal disruption induced by H2O2 in HUVECs. Inhibition of the NAD+ salvage pathway by FK866, a nicotinamide phosphoribosyltransferase inhibitor, maintained H2O2-induced cytoskeletal disruption, suggesting that intracellular NAD+ plays a crucial role in recovery from cytoskeletal disruption. Our findings provide further insights into the potential application of PARP inhibition and NMN supplementation for the treatment and prevention of diseases involving vascular hyperpermeability.

Niraparib as maintenance therapy in Japan: a retrospective observational study using a Japanese claims database.

OBJECTIVE: Epithelial ovarian cancer (EOC) is the leading cause of female mortality in gynecologic malignancies, with a rising incidence in Japan. This study aimed to validate the treatment patterns and safety of niraparib as maintenance therapy for EOC following initial chemotherapy in clinical practice in Japan. METHODS: Leveraging claims data between April 2008 and December 2022, this descriptive study comprised EOC-diagnosed patients receiving initial platinum-based chemotherapy, debulking surgery, and niraparib as maintenance therapy. Patient characteristics, prescription status, transfusion details, and laboratory data were assessed and reported as summary statistics and frequencies. RESULTS: Among 291 patients, the median age was 64.0 years and 94.5% received a 200-mg daily dose of niraparib. At week 12, 78.7% (229/291) continued niraparib treatment, 21.3% (62/291) discontinued, and 52.2% (152/291) required treatment interruptions. Of the 62 patients who discontinued treatment, 27 patients initiated subsequent EOC treatment within 12 weeks following niraparib discontinuation. Blood transfusions were needed in 10.3% (30/291), and of 55 patients with available laboratory data, 61.8% (34/55) had decreased platelet count <100,000/µL, 25.5% (14/55) had decreased hemoglobin level <8 g/dL, and 22.7% (5/22) had decreased neutrophil count <1,000/µL, meeting the criteria for treatment interruption. Among those with thrombocytopenia, 88.2% (30/34) were able to either resume or continue treatment. CONCLUSION: Niraparib demonstrated favorable tolerability in Japanese patients with advanced EOC, with effective management of thrombocytopenia through dose adjustments and supportive care, supporting its viability as post-chemotherapy maintenance therapy.

Expert consensus: Profiling and management of advanced or metastatic epithelial ovarian cancer / Consenso de expertos basado en la evidencia: perfilamiento y manejo del carcinoma epitelial de ovario de alto grado avanzado.

Introduction and objective: The approach to patients with advanced or metastatic high-grade epithelial ovarian cancer (EOC) has evolved over time with the advent of new therapies and multimodal strategies. The objective of this consensus of experts is to generate national recommendations for the profiling and management of advanced or metastatic high-grade OEC, defined as stages III and IV of the "The International Federation of Gynecology and Obstetrics (FIGO) classification at the time of diagnosis to base on the literature review that included international evidence-based clinical practice guidelines (CPG). Material and methods: Eleven panelists (oncologists and gynecological oncologists) answered 8 questions about the profiling and management of advanced or metastatic ovarian epithelial carcinoma. The panelists were chosen for their academic profile and influence in national health institutions. Guidelines from the "ESMO Standardized Operating Procedures Consensus Conference" were used to develop the consensus. It was agreed that the level of agreement to accept a recommendation should be ≥ 80%. The document was peer reviewed. Results: Eight general recommendations are made, which are presented into five domains. Some of these recommendations are subdivided into specific recommendations. Initial treatment Recommendation 1.1 Complete primary cytoreduction (PCS) surgery is suggested as the initial therapy of choice for patients with high-grade or metastatic EOC, which should ideally be carried out in centers with experience, followed by adjuvant therapy. 1.2 Neoadjuvant chemotherapy followed by interval cytoreduction surgery (ICS) is suggested in those who are unlikely to achieve a complete cytoreduction in PCS either due to unresectable metastatic disease or who present unresectability criteria (imaging, laparoscopic and/or by laparotomy) and that have been defined by a gynecological oncologist and patients with poor functional status and comorbidities according to the criteria of the multidisciplinary team (clinical oncology, gynecological oncology, radiology, etc.). Recommendation 2. In patients with high-grade epithelial ovarian cancer (EOC), in stage III locally advanced or metastatic, who received neoadjuvant chemotherapy and achieved a complete or partial response (cytoreduction with tumor residue < 2.5 mm), the use of Hyperthermic IntraPeritoneal Chemotherapy (HIPEC) could be considered as an alternative to standard platinum-based adjuvant intravenous chemotherapy during interval cytoreductive surgery, after discussion in a multidisciplinary tumor board, at a center experienced in treating this type of patients. Use of genetic testing. Recommendation 3. It is suggested at the time of diagnosis to offer molecular genetic testing to all patients with high-grade advanced or metastatic EOC regardless of family history. Recommendation 4. It is suggested to offer genetic counseling, by qualified personnel, to all patients with high-grade advanced or metastatic EOC who are ordered genetic testing. Recommendation 5. It is suggested that all patients with advanced or metastatic high-grade EOC undergo a germ panel that includes the Breast Cancer Susceptibility Genes 1/2 genes (BRCA 1/2) and the other susceptibility genes according to with institutional protocols and the availability of genetic testing panels; If it is negative, then somatic testing should be performed that includes the homologous recombination deficiency (HRD) status, regardless of family history. Adjuvant Therapy Recommendation 6. 6.1. It is suggested that all patients with advanced stage III/IV EOC, with PSC of (0-2), got adjuvant intravenous chemotherapy as standard treatment within six weeks after Prc. It is suggested paclitaxel/carboplatin. Recommendation 6.2. It is suggested to use standard chemotherapy base on platinum plus Bevacizumab as adjuvant chemotherapy to patients with high-risk disease (EOC stage IV or stage III with suboptimal tumor cytoreduction), following by bevacizumab as maintenance. The use of bevacizumab as maintenance therapy is not recommended if bevacizumab was not included in the first line of treatment. We suggested the dose used in GOG-0218 and ICON7 trials. Recommendation 6.3 It is suggested combined intravenous/intraperitoneal chemotherapy only for selected patients, with optimal cytoreduction (residual lesions < 1 cm), especially those without residual disease (R0) and who are evaluated in a multidisciplinary meeting. It is not considered standard treatment. Recommendation 6.4. 6.4.1 It is suggested to use Poly ADP ribose polymerase (PARP) inhibitors such as olaparib or niraparib as maintenance after receiving first-line chemotherapy in patients with stage III/IV BRCA1/2 positive EOC who received platinumbased chemotherapy and obtained complete response/partial response (CR/PR), 6.4.2 It is suggested to use olaparib alone or in combination with bevacizumab or niraparib in patients with stage III/IV BRCA1/2 positive EOC who received platinum-based chemotherapy plus bevacizumab and achieved CR/PR. 6.4.3 It is suggested to use niraparibin patients with stage III/IV BRCA1/2 negative or unknown EOC who received platinum-based chemotherapy and achieved CR/PR. 6.4.4 It is suggested to use bevacizumab or olaparib plus bevacizumab in patients with EOC stage III/IV BRCA1/2 negative or unknown (HRD positive) who received platinum-based chemotherapy plus bevacizumab and obtained CR/PR. Treatment of disease relapse Recommendation 7. Secondary cytoreductive surgery followed by chemotherapy is suggested for selected patients with high-grade advanced EOC in first relapse, platinum-sensitive (platinum-free interval ≥ 6 months), positive "Arbeitsgemeinschaft Gynäkologische Onkologie ­ AGO" score or "I-model" positive (< 4.7) with a potential resection to R0 in centers with access to optimal surgical and postoperative support. Note: Platinum-free interval and AGO score have only been developed as positive predictors of complete resection and not to exclude patients from surgery. Recommendation 8. 8.1 For patients with relapse advanced high-grade EOC platinum-sensitive, the following is suggested: Platinum-based combination chemotherapy: carboplatin/liposomal doxorubicin or carboplatin/paclitaxel or carboplatin/nab-paclitaxel or carboplatin/docetaxel or carboplatin/gemcitabine) for six cycles. If combination therapy is not tolerated, give carboplatin or cisplatin alone. Combination chemotherapy (carboplatin/gemcitabine or carboplatin/paclitaxel or carboplatin/doxorubicin liposomal) plus bevacizumab followed by bevacizumab as maintenance (until progression or toxicity). Recommendation 8.2 For patients with relapsed advanced high-grade EOC platinum-resistant, it is suggested: Sequential treatment with chemotherapy, preferably with a non-platinum single agent (weekly paclitaxel or pegylated liposomal doxorubicin or docetaxel or oral etoposide or gemcitabine or trabectidine or, topotecan). Weekly paclitaxel or pegylated liposomal doxorubicin or topotecan could be administrate with or without bevacizumab. Other agents are considered potentially active (capecitabine, cyclophosphamide, ifosfamide, irinotecan, oxaliplatin, pemetrexed, vinorelbine, cyclophosphamide) could be recommended for later lines. Hormone receptor-positive patients who do not tolerate or have no response to cytotoxic regimens may receive hormone therapy with tamoxifen or other agents, including aromatase inhibitors (anastrozole and letrozole) or leuprolide acetate, or megestrol acetate. Patients with a performance score ≥ 3 should be considered only for best supportive care. Recommendation 8.3 Maintenance therapy with PARP inhibitors: It is suggested in patients with relapse advanced high-grade EOC stage III/IV BRCA1/2 (positive, negative or unknown) who have received two or more lines of platinum-based chemotherapy and have achieved CR/PR, use olaparib, niraparib or rucaparib. Niraparib could be useful in BRCA 1/2 +/-/unknown patients, as rucaparib, however, the latter does not yet have approval from the regulatory office in Colombia. Conclusions: It is expected that the recommendations issued in this consensus will contribute to improving clinical care, oncological impact, and quality of life of these women.

Introducción y objetivo: el abordaje de pacientes con cáncer epitelial de ovario (CEO) de alto grado avanzado o metastásico ha ido evolucionando a través del tiempo con el advenimiento de nuevas terapias y estrategias multimodales. El objetivo de este consenso de expertos es generar recomendaciones nacionales para el perfilamiento y manejo del CEO de alto grado avanzado o metastásico, definido como estadios III y IV de la clasificación de la Federación Internacional de Ginecología y Obstetricia (FIGO) al momento del diagnóstico, a partir de la revisión de la literatura que incluyó guías de práctica clínica (GPC) internacionales basadas en la evidencia. Materiales y métodos: once panelistas (oncólogos y ginecólogos oncólogos) respondieron ocho preguntas sobre el perfilamiento y manejo del carcinoma epitelial de ovario avanzado o metastásico. Los panelistas fueron escogidos por su perfil académico e influencia en instituciones de salud nacionales. Para el desarrollo del consenso se utilizaron los lineamientos de la "Conferencia de consenso de procedimientos operativos estandarizados de ESMO". Se definió que el nivel de acuerdo para aceptar una recomendación debía ser ≥ 80%. El documento fue revisado por pares. Resultados: Se hacen 8 recomendaciones generales, presentadas en cinco dominios; algunas de ellas se subdividen en recomendaciones específicas. Tratamiento inicial Recomendación 1 1.1. Como terapia inicial de elección para pacientes con CEO de alto grado o metastásico se sugiere la cirugía de citorreducción primaria (Cpr) completa que, idealmente, debe realizarse en centros con experiencia, seguida de terapia adyuvante. 1.2. Se sugiere quimioterapia neoadyuvante seguida de cirugía de citorreducción de intervalo (Cint) en quienes sea improbable alcanzar una citorreducción completa en la Cpr, bien sea por enfermedad metastásica no resecable o que presenten criterios de irresecabilidad (imagenológicos, laparoscópicos o por laparotomía) que hayan sido definidos por un ginecólogo oncólogo. También en pacientes con un pobre estado funcional y comorbilidades de acuerdo con el criterio del equipo multidisciplinario (oncología clínica, ginecología oncológica, radiología, etc.). Recomendación 2. En pacientes con CEO de alto grado, en estadio III localmente avanzado o metastásico, que recibieron quimioterapia neoadyuvante y alcanzaron respuesta completa o parcial (citorreducción con residuo tumoral < 2,5 mm), se podría evaluar el uso de la quimioterapia intraperitoneal hipertérmica (Hyperthermic IntraPeritoneal Chemotherapy - HIPEC) como alternativa a la quimioterapia IV adyuvante estándar basada en platinos durante la Cint, previa discusión en junta multidisciplinaria, en un centro de experiencia en este tipo de pacientes. Uso de pruebas genéticas Recomendación 3. Al momento del diagnóstico, se sugiere ofrecer testeo molecular genético a toda paciente con CEO de alto grado avanzado o metastásico, independientemente de la historia familiar. Recomendación 4. Se sugiere ofrecer asesoramiento genético, por parte de personal calificado, a toda paciente con CEO de alto grado avanzado o metastásico a quien se le ordene un testeo genético. Recomendación 5. Se sugiere que a toda paciente con CEO de alto grado avanzado o metastásico se le realice panel germinal que incluya los genes de susceptibilidad al cáncer de mama 1/2 (BRCA 1/2) y los otros genes de susceptibilidad de acuerdo con los protocolos institucionales y la disponibilidad de paneles de testeo genético; si es negativo entonces se debería realizar testeo somático que incluya el estatus de deficiencia de la recombinación homóloga (homologous recombination deficiency - HRD), independientemente de la historia familiar. Terapia adyuvante Recomendación 6 6.1. Se sugiere que a toda paciente con CEO estadios III/IV avanzado o metastásico, con estatus de desempeño (performance score care - PSC) de 0-2 se le administre como tratamiento estándar quimioterapia intravenosa (IV) adyuvante dentro de las seis semanas posteriores a la Cpr. Se sugiere administrar paclitaxel/carboplatino. 6.2. Se sugiere utilizar quimioterapia estándar basada en platino más bevacizumab como adyuvancia en pacientes con enfermedad de alto riesgo (CEO estadios IV o III con citorreducción tumoral subóptima), continuando con bevacizumab como mantenimiento. No se recomienda el uso de bevacizumab como terapia de mantenimiento si no se incluyó en la primera línea de tratamiento. Se sugiere seguir los esquemas de los estudios Gynecologic Oncology Group Study (GOG-0218) e International Collaborative Ovarian Neoplasm (ICON7). 6.3. Se sugiere la quimioterapia combinada IV/intraperitoneal (IP) solo para pacientes seleccionadas, con una citorreducción óptima (lesiones residuales < 1 cm), en especial aquellas sin enfermedad residual (R0) y que sean evaluadas en junta multidisciplinaria. La quimioterapia combinada IV/IP no se considera como tratamiento estándar. 6.4. 6.4.1. Se sugiere utilizar inhibidores de poli(ADP-ribosa) polimerasa (PARP) tales como olaparib o niraparib como mantenimiento después de recibir una primera línea de quimioterapia en pacientes con CEO estadios III/IV BRCA1/2 positivo que recibieron quimioterapia basada en platino y obtuvieron respuesta completa/respuesta parcial (RC/RP). 6.4.2. Se sugiere utilizar olaparib solo o en combinación con bevacizumab o niraparib en pacientes con CEO estadios III/IV BRCA1/2 positivo que recibieron quimioterapia basada en platino más bevacizumab y obtuvieron RC/RP. 6.4.3. Se sugiere utilizar niraparib en pacientes con CEO estadio III/IV BRCA1/2 negativo o desconocido que recibieron quimioterapia basada en platino y obtuvieron RC/RP. 6.4.4. Se sugiere utilizar bevacizumab u olaparib más bevacizumab en pacientes con CEO estadios III/IV BRCA1/2 negativo o desconocido (HRD positivo) que recibieron quimioterapia basada en platino más bevacizumab y obtuvieron RC/RP. Tratamiento de la recaída de la enfermedad Recomendación 7. Se sugiere la realización de la cirugía de citorreducción secundaria (Csec), seguida de quimioterapia, a pacientes seleccionadas con CEO de alto grado avanzado o metastásico en primera recaída, platino-sensibles (intervalo libre de platinos ≥ 6 meses), puntuación Arbeitsgemeinschaft Gynäkologische Onkologie (AGO) positiva o Integrate model (I-Model) positivo (< 4,7), y con una potencial resección a R0, en centros con acceso a soporte quirúrgico y posoperatorio óptimo. Nota: el intervalo libre de tratamiento con platinos y la puntuación AGO solo se han desarrollado como predictores positivos de resección completa y no para excluir a las pacientes de la cirugía. Recomendación 8 8.1. Para pacientes con CEO de alto grado avanzado o metastásico en recaída platino-sensibles se sugiere: Quimioterapia combinada basada en platino: carboplatino/doxorrubicina liposomal o carboplatino/paclitaxel o carboplatino/ nab-paclitaxel o carboplatino/docetaxel o carboplatino/gemcitabina, por seis ciclos. Si no se tolera la terapia combinada, dar carboplatino o cisplatino solo. Quimioterapia combinada: carboplatino/gemcitabina o carboplatino/paclitaxel o carboplatino/doxorubicina liposomal, más bevacizumab, seguida de bevacizumab como mantenimiento (hasta progresión o toxicidad). 8.2. Para pacientes con CEO de alto grado avanzado o metastásico en recaída, platino-resistentes, se sugiere: Tratamiento secuencial con quimioterapia, preferiblemente con un agente único que no sea un platino (paclitaxel semanal o doxorrubicina liposomal pegilada o docetaxel o etopósido oral o gemcitabina o trabectidina o topotecan). El paclitaxel semanal o la doxorrubicina liposomal pegilada o el topotecan pueden ser administrados con o sin bevacizumab. Existen otros agentes que se consideran potencialmente act ivos (capecitabina, ciclofosfamida, ifosfamida, irinotecán, oxaliplatino, pemetrexed, vinorelbina, ciclofosfamida), que se podrían recomendar para líneas posteriores. Las pacientes con receptores hormonales positivos que no toleran o no tienen respuesta a los regímenes citotóxicos pueden recibir terapia hormonal con tamoxifeno u otros agentes, incluidos los inhibidores de la aromatasa (anastrozol y letrozol) o acetato de leuprolide o acetato de megestrol. Pacientes con PSC ≥ 3 deberían ser consideradas solo para el mejor cuidado de soporte. 8.3. Terapia de mantenimiento con inhibidores PARP. Para pacientes con CEO de alto grado avanzado o metastásico en recaída estadios III/IV BRCA1/2 (positivo, negativo o desconocido), que hayan recibido dos o más líneas de quimioterapia basada en platino y hayan alcanzado RC/RP, se sugiere utilizar olaparib, niraparib o rucaparib. El niraparib podría ser útil en pacientes BRCA 1/2 +/-/desconocido, al igual que el rucaparib, sin embargo, este último no tiene aún aprobación del ente regulador en Colombia. Conclusiones: se espera que las recomendaciones emitidas en este consenso contribuyan a mejorar la atención clínica, el impacto oncológico y la calidad de vida de estas mujeres.

Lipid droplets: a candidate new research field for epithelial ovarian cancer.

Ovarian clear cell carcinoma (OCCC) is a histological subtype that constitutes approximately 20% of epithelial ovarian cancer cases in Asian countries, but has a relatively low incidence in Western countries. Meanwhile, clear cell renal cell carcinoma (ccRCC) is a major subtype of kidney cancer. OCCC and ccRCC resemble one another histologically and have clear cytoplasmic appearances. Studies have revealed some genetic similarities between OCCC and ccRCC. However, information regarding common biological background factors between these cancers remains scarce. For example, accumulation of cellular lipid droplets was shown to play a crucial role in ccRCC progression, while similar information is lacking for OCCC. In this perspective article, we propose that lipid droplets may be candidates for future exploration to better understand the common biological backgrounds between OCCC and ccRCC, potentially leading to subtype-specific treatment strategies. We further discuss the relationship between poly ADP-ribose polymerase inhibition treatment and lipid metabolism because this therapeutic strategy has attracted considerable attention as a treatment for epithelial ovarian cancer.

Niraparib in Japanese patients with platinum-sensitive recurrent ovarian cancer: final results of a multicenter phase 2 study.

OBJECTIVE: This study evaluated the long-term safety and efficacy of niraparib in Japanese patients with platinum-sensitive recurrent ovarian cancer. METHODS: This was a follow-up analysis of a phase 2, multicenter, open-label, single-arm study in Japanese women with platinum-sensitive, relapsed ovarian cancer. Participants received niraparib (starting dose 300 mg) once daily in continuous 28-day cycles. The primary endpoint was the incidence of Grade 3 or 4 thrombocytopenia-related events (defined as the overall incidence of the MedDRA Preferred Terms "thrombocytopenia" and "platelet count decreased") occurring in the 30 days after initial administration of niraparib, and secondary endpoints included evaluation of treatment-emergent adverse events and progression-free survival. RESULTS: Nineteen patients (median age, 62 years; median body weight, 53.9 kg) were enrolled. As previously reported, the incidence of Grade 3 or 4 thrombocytopenia-related events during the first 30 days of treatment was 31.6%. At data cutoff, median (range) treatment exposure was 504.0 (56-1,054) days and mean ± standard deviation dose intensity was 154.4±77.5 mg/day. The most common treatment-emergent adverse events were nausea (n=14, 73.7%), decreased platelet count (n=12, 63.2%), decreased neutrophil count (n=11, 57.9%), anemia, vomiting, and decreased appetite (all n=9, 47.4%). One patient was diagnosed with treatment-related leukemia, which resulted in death. Median (95% confidence interval) progression-free survival was 18.0 (5.6-26.7) months. CONCLUSION: Overall, the safety profile of niraparib was considered manageable in this study population of Japanese patients with platinum-sensitive, relapsed ovarian cancer and was consistent with that observed in studies of non-Japanese patients. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03759587.

Development and Characterization of Recombinant ADP-Ribose Binding Reagents that Allow Simultaneous Detection of Mono and Poly ADP-Ribose.

ADP-ribosylation (ADPRylation) is a post-translational modification (PTM) of proteins mediated by the activity of a variety of ADP-ribosyltransferase (ART) enzymes, such as the Poly (ADP-ribose) Polymerase (PARP) family of proteins. This PTM is diverse in both form and biological functions, which makes it a highly interesting modification, but difficult to study due to limitations in reagents available to detect the diversity of ADP-ribosylation. Recently we developed a set of recombinant antibody-like ADP-ribose binding proteins using naturally occurring ADPR binding domains (ARBDs), including macrodomains and WWE domains, functionalized by fusion to the constant "Fc" region of rabbit immunoglobulin. Herein, we present an expansion of this biological toolkit, where we have replaced the rabbit Fc sequence with the sequence from two other species, mouse and goat. These new reagents are based on a previously characterized set of naturally-occuring ARBDs with known specificity. Characterization of the new reagents demonstrates that they can be detected in a species-dependent manner by secondary immunogical tools, recognize specific ADP-ribose moieties, and can be used for simultaneous detection of MAR and PAR at single cell resolution in various antibody-based assays . The expansion of this toolkit will allow for more multiplexed assessments of the complexity of ADPRylation biology in many biological systems.

Deletion of CD38 enhances CD19 chimeric antigen receptor T cell function.

Cell surface molecules transiently upregulated on activated T cells can play a counter-regulatory role by inhibiting T cell function. Deletion or blockade of such immune checkpoint receptors has been investigated to improve the function of engineered immune effector cells. CD38 is upregulated on activated T cells, and although there have been studies showing that CD38 can play an inhibitory role in T cells, how it does so has not fully been elucidated. In comparison with molecules such as PD1, CTLA4, LAG3, and TIM3, we found that CD38 displays more sustained and intense expression following acute activation. After deleting CD38 from human chimeric antigen receptor (CAR) T cells, we showed relative resistance to exhaustion in vitro and improved anti-tumor function in vivo. CD38 is a multifunctional ectoenzyme with hydrolase and cyclase activities. Reintroduction of CD38 mutants into T cells lacking CD38 provided further evidence supporting the understanding that CD38 plays a crucial role in producing the immunosuppressive metabolite adenosine and utilizing nicotinamide adenine dinucleotide (NAD) in human T cells. Taken together, these results highlight a role for CD38 as an immunometabolic checkpoint in T cells and lead us to propose CD38 deletion as an additional avenue for boosting CAR T cell function.

1,25-Dihydroxyvitamin D3 Suppresses UV-Induced Poly(ADP-Ribose) Levels in Primary Human Keratinocytes, as Detected by a Novel Whole-Cell ELISA.

Photoprotective properties of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) to reduce UV-induced DNA damage have been established in several studies. UV-induced DNA damage in skin such as single or double strand breaks is known to initiate several cellular mechanisms including activation of poly(ADP-ribose) (pADPr) polymerase-1 (PARP-1). DNA damage from UV also increases extracellular signal-related kinase (ERK) phosphorylation, which further increases PARP activity. PARP-1 functions by using cellular nicotinamide adenine dinucleotide (NAD+) to synthesise pADPr moieties and attach these to target proteins involved in DNA repair. Excessive PARP-1 activation following cellular stress such as UV irradiation may result in excessive levels of cellular pADPr. This can also have deleterious effects on cellular energy levels due to depletion of NAD+ to suboptimal levels. Since our previous work indicated that 1,25(OH)2D3 reduced UV-induced DNA damage in part through increased repair via increased energy availability, the current study investigated the effect of 1,25(OH)2D3 on UV-induced PARP-1 activity using a novel whole-cell enzyme- linked immunosorbent assay (ELISA) which quantified levels of the enzymatic product of PARP-1, pADPr. This whole cell assay used around 5000 cells per replicate measurement, which represents a 200-400-fold decrease in cell requirement compared to current commercial assays that measure in vitro pADPr levels. Using our assay, we observed that UV exposure significantly increased pADPr levels in human keratinocytes, while 1,25(OH)2D3 significantly reduced levels of UV-induced pADPr in primary human keratinocytes to a similar extent as a known PARP-1 inhibitor, 3-aminobenzamide (3AB). Further, both 1,25(OH)2D3 and 3AB as well as a peptide inhibitor of ERK-phosphorylation significantly reduced DNA damage in UV-exposed keratinocytes. The current findings support the proposal that reduction in pADPr levels may be critical for the function of 1,25(OH)2D3 in skin to reduce UV-induced DNA damage.

Identification of Poly(ADP-ribose) Polymerase 9 (PARP9) as a Potent Suppressor for Mycobacterium tuberculosis Infection.

ADP-ribosylation is a reversible and dynamic post-translational modification mediated by ADP-ribosyltransferases (ARTs). Poly(ADP-ribose) polymerases (PARPs) are an important family of human ARTs. ADP-ribosylation and PARPs have crucial functions in host-pathogen interaction, especially in viral infections. However, the functions and potential molecular mechanisms of ADP-ribosylation and PARPs in Mycobacterium infection remain unknown. In this study, bioinformatics analysis revealed significantly changed expression levels of several PARPs in tuberculosis patients compared to healthy individuals. Moreover, the expression levels of these PARPs returned to normal following tuberculosis treatment. Then, the changes in the expression levels of PARPs during Mycobacterium infection were validated in Tohoku Hospital Pediatrics-1 (THP1)-induced differentiated macrophages infected with Mycobacterium model strains bacillus Calmette-Guérin (BCG) and in human lung adenocarcinoma A549 cells infected with Mycobacterium smegmatis (Ms), respectively. The mRNA levels of PARP9, PARP10, PARP12, and PARP14 were most significantly increased during infection, with corresponding increases in protein levels, indicating the possible biological functions of these PARPs during Mycobacterium infection. In addition, the biological function of host PARP9 in Mycobacterium infection was further studied. PARP9 deficiency significantly increased the infection efficiency and intracellular proliferation ability of Ms, which was reversed by the reconstruction of PARP9. Collectively, this study updates the understanding of changes in PARP expression during Mycobacterium infection and provides evidence supporting PARP9 as a potent suppressor for Mycobacterium infection. Supplementary Information: The online version contains supplementary material available at 10.1007/s43657-023-00112-2.

The efficacy and safety of PARP inhibitors in mCRPC with HRR mutation in second-line treatment: a systematic review and bayesian network meta-analysis.

BACKGROUND: Poly (ADP- ribose) polymerase inhibitors (PARPi) has been increasingly adopted for metastatic castration-resistance prostate cancer (mCRPC) patients with homologous recombination repair deficiency (HRD). However, it is unclear which PARPi is optimal in mCRPC patients with HRD in 2nd -line setting. METHOD: We conducted a systematic review of trials regarding PARPi- based therapies on mCRPC in 2nd -line setting and performed a Bayesian network meta-analysis (NMA). Radiographic progression-free survival (rPFS) was assessed as primary outcome. PSA response and adverse events (AEs) were evaluated as secondary outcomes. Subgroup analyses were performed according to specific genetic mutation. RESULTS: Four RCTs comprised of 1024 patients (763 harbored homologous recombination repair (HRR) mutations) were identified for quantitative analysis. Regarding rPFS, olaparib monotherapy, rucaparib and cediranib plus olaparib showed significant improvement compared with ARAT. Olaparib plus cediranib had the highest surface under cumulative ranking curve (SUCRA) scores (87.5%) for rPFS, followed by rucaparib, olaparib and olaparib plus abiraterone acetate prednisone. For patients with BRCA 1/2 mutations, olaparib associated with the highest probability (98.1%) of improved rPFS. For patients with BRCA-2 mutations, olaparib and olaparib plus cediranib had similar efficacy. However, neither olaparib nor rucaparib showed significant superior effectiveness to androgen receptor-axis-targeted therapy (ARAT) in patients with ATM mutations. For safety, olaparib showed significantly lower ≥ 3 AE rate compared with cediranib plus olaparib (RR: 0.72, 95% CI: 0.51, 0.97), while olaparib plus cediranib was associated with the highest risk of all-grade AE. CONCLUSION: PARPi-based therapy showed considerable efficacy for mCRPC patients with HRD in 2nd -line setting. However, patients should be treated accordingly based on their genetic background as well as the efficacy and safety of the selected regimen. TRIAL REGISTRATION: CRD42023454079.

[18F]F-Poly(ADP-Ribose) Polymerase Inhibitor Radiotracers for Imaging PARP Expression and Their Potential Clinical Applications in Oncology.

Including poly(ADP-ribose) polymerase (PARP) inhibitors in managing patients with inoperable tumors has significantly improved outcomes. The PARP inhibitors hamper single-strand deoxyribonucleic acid (DNA) repair by trapping poly(ADP-ribose)polymerase (PARP) at sites of DNA damage, forming a non-functional "PARP enzyme-inhibitor complex" leading to cell cytotoxicity. The effect is more pronounced in the presence of PARP upregulation and homologous recombination (HR) deficiencies such as breast cancer-associated gene (BRCA1/2). Hence, identifying HR-deficiencies by genomic analysis-for instance, BRCA1/2 used in triple-negative breast cancer-should be a part of the selection process for PARP inhibitor therapy. Published data suggest BRCA1/2 germline mutations do not consistently predict favorable responses to PARP inhibitors, suggesting that other factors beyond tumor mutation status may be at play. A variety of factors, including tumor heterogeneity in PARP expression and intrinsic and/or acquired resistance to PARP inhibitors, may be contributing factors. This justifies the use of an additional tool for appropriate patient selection, which is noninvasive, and capable of assessing whole-body in vivo PARP expression and evaluating PARP inhibitor pharmacokinetics as complementary to the currently available BRCA1/2 analysis. In this review, we discuss [18F]Fluorine PARP inhibitor radiotracers and their potential in the imaging of PARP expression and PARP inhibitor pharmacokinetics. To provide context we also briefly discuss possible causes of PARP inhibitor resistance or ineffectiveness. The discussion focuses on TNBC, which is a tumor type where PARP inhibitors are used as part of the standard-of-care treatment strategy.

Skin metastasis from ovarian cancer with somatic BRCA1 mutation: A case report and literature review.

Skin metastasis from ovarian cancer is rare, and its prognosis is poor. Effective therapeutic strategies are currently lacking, but the combination of various treatment methods shrink the tumor and relieve symptoms. The present study reports a rare case of advanced ovarian cancer with skin metastases and intestinal wall thickening, along with a BRCA1 DNA repair associated (BRCA1) mutation. After standard first-line treatment and non-standard second-line treatment, the patient developed skin metastases. The patient's skin itching, pain and lesions were completely relieved after administering bevacizumab in combination with paclitaxel and carboplatin. After 4 months, skin metastases recurred along with anal distension during maintenance treatment with oral poly(ADP ribose) polymerase (PARP) inhibitors. The patient was treated again with bevacizumab combined with docetaxel, and the anal distension was significantly relieved. Angiogenesis therapy combined with chemotherapy is effective, but that the disease-free survival time is short, and PARP inhibitor maintenance effect is limited even in cases with a BRCA1 gene mutation.

Novel anti-Acanthamoeba effects elicited by a repurposed poly (ADP-ribose) polymerase inhibitor AZ9482.

Introduction: Acanthamoeba infection is a serious public health concern, necessitating the development of effective and safe anti-Acanthamoeba chemotherapies. Poly (ADP-ribose) polymerases (PARPs) govern a colossal amount of biological processes, such as DNA damage repair, protein degradation and apoptosis. Multiple PARP-targeted compounds have been approved for cancer treatment. However, repurposing of PARP inhibitors to treat Acanthamoeba is poorly understood. Methods: In the present study, we attempted to fill these knowledge gaps by performing anti-Acanthamoeba efficacy assays, cell biology experiments, bioinformatics, and transcriptomic analyses. Results: Using a homology model of Acanthamoeba poly (ADP-ribose) polymerases (PARPs), molecular docking of approved drugs revealed three potential inhibitory compounds: olaparib, venadaparib and AZ9482. In particular, venadaparib exhibited superior docking scores (-13.71) and favorable predicted binding free energy (-89.28 kcal/mol), followed by AZ9482, which showed a docking score of -13.20 and a binding free energy of -92.13 kcal/mol. Notably, the positively charged cyclopropylamine in venadaparib established a salt bridge (through E535) and a hydrogen bond (via N531) within the binding pocket. For comparison, AZ9482 was well stacked by the surrounding aromatic residues including H625, Y652, Y659 and Y670. In an assessment of trophozoites viability, AZ9482 exhibited a dose-and time-dependent anti-trophozoite effect by suppressing Acanthamoeba PARP activity, unlike olaparib and venadaparib. An Annexin V-fluorescein isothiocyanate/propidium iodide apoptosis assay revealed AZ9482 induced trophozoite necrotic cell death rather than apoptosis. Transcriptomics analyses conducted on Acanthamoeba trophozoites treated with AZ9482 demonstrated an atlas of differentially regulated proteins and genes, and found that AZ9482 rapidly upregulates a multitude of DNA damage repair pathways in trophozoites, and intriguingly downregulates several virulent genes. Analyzing gene expression related to DNA damage repair pathway and the rate of apurinic/apyrimidinic (AP) sites indicated DNA damage efficacy and repair modulation in Acanthamoeba trophozoites following AZ9482 treatment. Discussion: Collectively, these findings highlight AZ9482, as a structurally unique PARP inhibitor, provides a promising prototype for advancing anti-Acanthamoeba drug research.

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.