7-Methylguanine Inhibits Colon Cancer Growth in Vivo.

7-Methylguanine (7-MG) is a natural inhibitor of poly(ADP-ribose) polymerase 1 and tRNA-guanine transglycosylase, the enzymatic activity of which is central for the proliferation of cancer cells. Recently, a number of preclinical tests have demonstrated the safety of 7-MG and a regimen of intragastric administration was established in mice. In the present work, the pharmacological activity of 7-MG was studied in BALB/c and BALB/c nude mice with transplanted tumors. It was found that 7-MG effectively penetrates tumor tissue and suppresses colon adenocarcinoma growth in the Akatol model, as well as in a xenograft model with human HCT116 cells.

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.

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.

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.

Loss of cytidine deaminase expression as a potential attempt to counteract the process of carcinogenesis by reducing basal PARP-1 activity and increasing tau levels.

Cytidine deaminase (CDA) is a pyrimidine salvage pathway enzyme that catalyzes the hydrolytic deamination of free cytidine and deoxycytidine to uridine and deoxyuridine, respectively. Our team discovered that CDA deficiency is associated with several aspects of genetic instability, such as increased sister chromatid exchange and ultrafine anaphase bridge frequencies. Based on these results, we sought (1) to determine how CDA deficiency contributes to genetic instability, (2) to explore the possible relationships between CDA deficiency and carcinogenesis, and (3) to develop a new anticancer treatment targeting CDA-deficient tumors. This review summarizes our major findings indicating that CDA deficiency is associated with a genetic instability that does not confer an increased cancer risk. In light of our results and published data, I propose a novel hypothesis that loss of CDA, by reducing basal PARP-1 activity and increasing Tau levels, may reflect an attempt to prevent, slow or reverse the process of carcinogenesis.

Poly (ADP-ribose) Polymerase-1 modulations in the genesis of thrombosis.

Thrombosis, a coagulation disorder, occurs due to altered levels of coagulation, fibrinolytic and immune factors, which are otherwise known to maintain hemostasis in normal physiological conditions. Here, we review the direct and indirect participation of a multifunctional nuclear enzyme poly (ADP-ribose) polymerase-1 (PARP1) in the expression of key genes and cellular processes involved in thrombotic pathogenesis. PARP1 biological activities range from maintenance of genomic integrity, chromatin remodeling, base excision DNA repair, stress responses to cell death, angiogenesis and cell cycle pathways. However, under homeostatic imbalances, PARP1 activities are linked with the pathogenesis of diseases, including cancer, aging, neurological disorders, and cardiovascular diseases. Disease-associated distressed cells employ a variety of PARP-1 functions such as oxidative damage exacerbations, cellular energetics and apoptosis pathways, regulation of inflammatory mediators, promotion of endothelial dysfunction, and ERK-mediated signaling in pathogenesis. Thrombosis is one such pathogenesis that comprises exacerbation of coagulation cascade due to biochemical alterations in endothelial cells, platelet activation, overexpression of adhesion molecules, cytokines release, and leukocyte adherence. Thus, the activation of endothelial and inflammatory cells in thrombosis implicates a potential role of PARP1 activation in thrombogenesis. This review article explores the direct impact of PARP1 activation in the etiology of thrombosis and discusses PARP1-mediated endothelial dysfunction, inflammation, and epigenetic regulations in the disease manifestation. Understanding PARP1 functions associated with thrombosis may elucidate novel pathogenetic mechanisms and help in better disease management through newer therapeutic interventions targeting PARP1 activity.

Long non-coding RNA LIP interacts with PARP-1 influencing the efficiency of base excision repair.

In recent years, various long non-coding RNAs (lncRNAs) involved in DNA damage response (DDR) have been identified and studied to deepen our understanding. However, there are rare reports on the association between lncRNAs and base excision repair (BER). Our designed DNA microarray identified dozens of functionally unknown lncRNAs, and their transcription levels significantly increased upon exposure to DNA damage inducers. One of them, named LIP (Long noncoding RNA Interacts with PARP-1), exhibited a significant alteration in transcription in response to methyl methanesulfonate (MMS) and temozolomide (TMZ) treatments. LIP knockdown or knockout cell lines are sensitive to MMS and TMZ, indicating that LIP plays a crucial role in DDR. The loss or insufficiency of LIP significantly influences the efficiency of BER in human cells, and it suggests that LIP participates in the BER pathway. The interaction between LIP and a key factor in BER, poly (ADP-ribose) polymerase 1 (PARP-1), has been confirmed. We identified and characterized LIP, a lncRNA, which is involved in DDR, significantly influences BER efficiency, and interacts with the BER key factor PARP-1. This advances our understanding of the connection between lncRNAs and BER, presenting the potential for the discovery of new drug targets.

Stress-Induced Changes in Nucleocytoplasmic Localization of Crucial Factors in Gene Expression Regulation.

This study investigates the toxic effect of harmful materials, unfiltered by the placenta, on neonatal umbilical cord (UC) vessels, focusing on stress-induced adaptations in transcriptional and translational processes. It aims to analyze changes in pathways related to mRNA condensate formation, transcriptional regulation, and DNA damage response under maternal smoking-induced stress. UC vessels from neonates born to smoking (Sm) and nonsmoking mothers (Ctr) were examined. Immunofluorescence staining and confocal microscopy assessed the localization of key markers, including Transcription Complex Subunit 1 (CNOT1) and the largest subunit of RNA polymerase II enzyme (RPB1). Additionally, markers of DNA damage response, such as Poly(ADP-ribose) polymerase-1, were evaluated. In Sm samples, dissolution of CNOT1 granules in UC vessels was observed, potentially aiding stalled translation and enhancing transcription via RPB1 assembly and translocation. Control vessels showed predominant cytoplasmic RPB1 localization. Despite adaptive responses, Sm endothelial cells exhibited significant damage, indicated by markers like Poly(ADP-ribose) polymerase-1. Ex vivo metal treatment on control vessels mirrored Sm sample alterations, emphasizing marker roles in cell survival under toxic exposure. Maternal smoking induces specific molecular adaptations in UC vessels, affecting mRNA condensate formation, transcriptional regulation, and DNA damage response pathways. Understanding these intricate molecular mechanisms could inform interventions to improve neonatal health outcomes and mitigate adverse effects of toxic exposure during pregnancy.

Synthetic Derivatives of Natural ent-Kaurane Atractyligenin Disclose Anticancer Properties in Colon Cancer Cells, Triggering Apoptotic Cell Demise.

The antitumor activity of different ent-kaurane diterpenes has been extensively studied. Several investigations have demonstrated the excellent antitumor activity of synthetic derivatives of the diterpene atractyligenin. In this research, a series of new synthetic amides and their 15,19-di-oxo analogues obtained from atractyligenin by modifying the C-2, C-15, and C-19 positions were designed in order to dispose of a set of derivatives with different substitutions at the amidic nitrogen. Using different concentrations of the obtained compounds (10-300 µM) a reduction in cell viability of HCT116 colon cancer cells was observed at 48 h of treatment. All the di-oxidized compounds were more effective than their alcoholic precursors. The di-oxidized compounds had already reduced the viability of two colon cancer cells (HCT116 and Caco-2) at 24 h when used at low doses (2.5-15 µM), while they turned out to be poorly effective in differentiated Caco-2 cells, a model of polarized enterocytes. The data reported here provide evidence that di-oxidized compounds induced apoptotic cell death, as demonstrated by the appearance of condensed and fragmented DNA in treated cells, as well as the activation of caspase-3 and fragmentation of its target PARP-1.

miR-21-5p Modulates Airway Inflammation and Epithelial-Mesenchymal Transition Processes in a Mouse Model of Combined Allergic Rhinitis and Asthma Syndrome.

INTRODUCTION: Combined allergic rhinitis and asthma syndrome (CARAS) is a concurrent allergic symptom of diseases of allergic rhinitis and asthma. However, the mechanism of CARAS remains unclear. The study aimed to investigate the impact of microRNA-21 (miR-21) on CARAS via targeting poly (ADP-ribose) polymerase-1 (PARP-1) and phosphoinositide 3-kinase (PI3K)/AKT pathways. METHODS: The levels of miR-21-5p and PARP-1 in CARAS patients were detected by quantitative reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA). An ovalbumin-sensitized mouse model of CARAS was established. And knock down of miR-21-5p was constructed by intranasally administering with miR-21-5p shRNA-encoding adeno-associated virus vector. Airway resistance and airway inflammatory response were detected. ELISA was used to evaluate IL-4/IL-5/IL-13 levels in bronchoalveolar lavage fluid (BALF). Expression levels of E-cadherin, fibronectin, and α-SMA were determined using Western blotting. The levels of PARP-1 and the activation of PI3K/AKT were assayed. RESULTS: Downregulation of miR-21-5p relieved pathophysiological symptoms of asthma including airway hyperreactivity and inflammatory cell infiltration. Downregulation of miR-21-5p significantly reduced the levels of IL4, IL-5, and IL-13 in BALF. Additionally, downregulation of miR-21-5p inhibited the epithelial-mesenchymal transition (EMT) process in CARAS mice. Furthermore, miR-21-5p regulated PARP-1 and was involved in PI3K/AKT activation in CARAS mice. CONCLUSION: Downregulation of miR-21-5p ameliorated CARAS-associated lung injury by alleviating airway inflammation, inhibiting the EMT process, and regulating PARP-1/PI3K/AKT in a mouse model of CARAS.

Leveraging shape screening and molecular dynamics simulations to optimize PARP1-Specific chemo/radio-potentiators for antitumor drug design.

PARP1 plays a pivotal role in DNA repair within the base excision pathway, making it a promising therapeutic target for cancers involving BRCA mutations. Current study is focused on the discovery of PARP inhibitors with enhanced selectivity for PARP1. Concurrent inhibition of PARP1 with PARP2 and PARP3 affects cellular functions, potentially causing DNA damage accumulation and disrupting immune responses. In step 1, a virtual library of 593 million compounds has been screened using a shape-based screening approach to narrow down the promising scaffolds. In step 2, hierarchical docking approach embedded in Schrödinger suite was employed to select compounds with good dock score, drug-likeness and MMGBSA score. Analysis supplemented with decomposition energy, molecular dynamics (MD) simulations and hydrogen bond frequency analysis, pinpointed that active site residues; H862, G863, R878, M890, Y896 and F897 are crucial for specific binding of ZINC001258189808 and ZINC000092332196 with PARP1 as compared to PARP2 and PARP3. The binding of ZINC000656130962, ZINC000762230673, ZINC001332491123, and ZINC000579446675 also revealed interaction involving two additional active site residues of PARP1, namely N767 and E988. Weaker or no interaction was observed for these residues with PARP2 and PARP3. This approach advances our understanding of PARP-1 specific inhibitors and their mechanisms of action, facilitating the development of targeted therapeutics.

NAMPT/NAD+/PARP1 Pathway Regulates CFA-Induced Inflammatory Pain via NF-κB Signaling in Rodents.

Emerging evidence has implicated nicotinamide adenine dinucleotide (NAD+) metabolism in various inflammatory diseases. In the study, the role of NAD+ metabolism in Complete Freund's Adjuvant (CFA)-evoked inflammatory pain and the underlying mechanisms are investigated. The study demonstrated that CFA induced upregulation of nicotinamide phosphoribosyltransferase (NAMPT) in dorsal root ganglia (DRG) without significant changes in the spinal cord. Inhibition of NAMPT expression by intrathecal injection of NAMPT siRNA alleviated CFA-induced pain-like behavior, decreased NAD+ contents in DRG, and lowered poly-(ADP-ribose) polymerase 1 (PARP1) activity levels. These effects are all reversed by the supplement of nicotinamide mononucleotide (NMN). Inhibition of PARP1 expression by intrathecal injection of PARP1 siRNA alleviated CFA-induced pain-like behavior, while elevated NAD+ levels of DRG. The analgesic effect of inhibiting NAMPT/NAD+/PARP1 axis can be attributed to the downregulation of the NF-κB/IL-1ß inflammatory pathway. Double immunofluorescence staining showed that the expression of NAMPT/NAD+/PARP1 axis is restricted to DRG neurons. In conclusion, PARP1 activation in response to CFA stimulation, fueled by NAMPT-derived NAD+, mediates CFA-induced inflammatory pain through NF-κB/IL-1ß inflammatory pathway.

A Knockout of Poly(ADP-Ribose) Polymerase 1 in a Human Cell Line: An Influence on Base Excision Repair Reactions in Cellular Extracts.

Base excision repair (BER) is the predominant pathway for the removal of most forms of hydrolytic, oxidative, and alkylative DNA lesions. The precise functioning of BER is achieved via the regulation of each step by regulatory/accessory proteins, with the most important of them being poly(ADP-ribose) polymerase 1 (PARP1). PARP1's regulatory functions extend to many cellular processes including the regulation of mRNA stability and decay. PARP1 can therefore affect BER both at the level of BER proteins and at the level of their mRNAs. Systematic data on how the PARP1 content affects the activities of key BER proteins and the levels of their mRNAs in human cells are extremely limited. In this study, a CRISPR/Cas9-based technique was used to knock out the PARP1 gene in the human HEK 293FT line. The obtained cell clones with the putative PARP1 deletion were characterized by several approaches including PCR analysis of deletions in genomic DNA, Sanger sequencing of genomic DNA, quantitative PCR analysis of PARP1 mRNA, Western blot analysis of whole-cell-extract (WCE) proteins with anti-PARP1 antibodies, and PAR synthesis in WCEs. A quantitative PCR analysis of mRNAs coding for BER-related proteins-PARP2, uracil DNA glycosylase 2, apurinic/apyrimidinic endonuclease 1, DNA polymerase ß, DNA ligase III, and XRCC1-did not reveal a notable influence of the PARP1 knockout. The corresponding WCE catalytic activities evaluated in parallel did not differ significantly between the mutant and parental cell lines. No noticeable effect of poly(ADP-ribose) synthesis on the activity of the above WCE enzymes was revealed either.

A review of poly(ADP-ribose)polymerase-1 (PARP1) role and its inhibitors bearing pyrazole or indazole core for cancer therapy.

Cancer is a disease with a high mortality rate characterized by uncontrolled proliferation of abnormal cells. The hallmarks of cancer evidence the acquired cells characteristics that promote the growth of malignant tumours, including genomic instability and mutations, the ability to evade cellular death and the capacity of sustaining proliferative signalization. Poly(ADP-ribose) polymerase-1 (PARP1) is a protein that plays key roles in cellular regulation, namely in DNA damage repair and cell survival. The inhibition of PARP1 promotes cellular death in cells with homologous recombination deficiency, and therefore, the interest in PARP protein has been rising as a target for anticancer therapies. There are already some PARP1 inhibitors approved by Food and Drug Administration (FDA), such as Olaparib and Niraparib. The last compound presents in its structure an indazole core. In fact, pyrazoles and indazoles have been raising interest due to their various medicinal properties, namely, anticancer activity. Derivatives of these compounds have been studied as inhibitors of PARP1 and presented promising results. Therefore, this review aims to address the importance of PARP1 in cell regulation and its role in cancer. Moreover, it intends to report a comprehensive literature review of PARP1 inhibitors, containing the pyrazole and indazole scaffolds, published in the last fifteen years, focusing on structure-activity relationship aspects, thus providing important insights for the design of novel and more effective PARP1 inhibitors.

PARP-1 inhibitor alleviates cerebral ischemia/reperfusion injury by reducing PARylation of HK-1 and LDH in mice.

Poly (ADP-ribose) polymerase-1 (PARP-1) activity significantly increases during cerebral ischemia/reperfusion. PARP-1 is an NAD+-consumption enzyme. PARP-1 hyperactivity causes intracellular NAD+ deficiency and bioenergetic collapse, contributing to neuronal death. Besides, the powerful trigger of PARP-1 causes the catalyzation of poly (ADP-ribosyl)ation (PARylation), a posttranslational modification of proteins. Here, we found that PARP-1 was activated in the ischemic brain tissue during middle-cerebral-artery occlusion and reperfusion (MCAO/R) for 24 h, and PAR accumulated in the neurons in mice. Using immunoprecipitation, Western blotting, liquid chromatography-mass spectrometry, and 3D-modeling analysis, we revealed that the activation of PARP-1 caused PARylation of hexokinase-1 and lactate dehydrogenase-B, which, therefore, caused the inhibition of these enzyme activities and the resulting cell energy metabolism collapse. PARP-1 inhibition significantly reversed the activity of hexokinase and lactate dehydrogenase, decreased infarct volume, and improved neuronal deficiency. PARP-1 inhibitor combined with pyruvate further alleviated MCAO/R-induced ischemic brain injury in mice. As such, we conclude that PARP-1 inhibitor alleviates neuronal death partly by inhibiting the PARylation of metabolic-related enzymes and reversing metabolism reprogramming during cerebral ischemia/reperfusion injury in mice. PARP-1 inhibitor combined with pyruvate might be a promising therapeutic approach against brain ischemia/reperfusion injury.

USP36-mediated PARP1 deubiquitination in doxorubicin-induced cardiomyopathy.

Doxorubicin (Dox) is a potent antineoplastic agent, but its use is curtailed by severe cardiotoxicity, known as Dox-induced cardiomyopathy (DIC). The molecular mechanism underlying this cardiotoxicity remains unclear. Our current study investigates the role of Ubiquitin-Specific Protease 36 (USP36), a nucleolar deubiquitinating enzyme (DUB), in the progression of DIC and its mechanism. We found increased USP36 expression in neonatal rat cardiomyocytes and H9C2 cells exposed to Dox. Silencing USP36 significantly mitigated Dox-induced oxidative stress injury and apoptosis in vitro. Mechanistically, USP36 upregulation positively correlated with Poly (ADP-ribose) polymerase 1 (PARP1) expression, and its knockdown led to a reduction in PARP1 levels. Further investigation revealed that USP36 could bind to and mediate the deubiquitination of PARP1, thereby increasing its protein stability in cardiomyocytes upon Dox exposure. Moreover, overexpression of wild-type (WT) USP36 plasmid, but not its catalytically inactive mutant (C131A), stabilized PARP1 in HEK293T cells. We also established a DIC model in mice and observed significant upregulation of USP36 in the heart. Cardiac knockdown of USP36 in mice using a type 9 recombinant adeno-associated virus (rAAV9)-shUSP36 significantly preserved cardiac function after Dox treatment and protected against Dox-induced structural changes within the myocardium. In conclusion, these findings suggest that Dox promotes DIC progression by activating USP36-mediated PARP1 deubiquitination. This novel USP36/PARP1 axis may play a significant regulatory role in the pathogenesis of DIC.

Poly(ADP-ribose) polymerase-1 affects vasopressin-mediated AQP2 expression in collecting duct cells of the kidney.

Poly(ADP-ribosyl)ation (PARylation), as a posttranslational modification mediated by poly(ADP-ribose) polymerases (PARPs) catalyzing the transfer of ADP-ribose from NAD+ molecules to acceptor proteins, involves a number of cellular processes. As mice lacking the PARP-1 gene (Parp1) produce more urine, we investigated the role of PARP-1, the most prevalent member of the PARP family, in the vasopressin-responsive expression of aquaporin-2 (AQP2). In biotin-conjugated nicotinamide adenine dinucleotide (biotin-NAD+) pulldown and immunoprecipitation assays of poly(ADP)-ribose in mpkCCDc14 cells, immunoblots demonstrated that 1-deamino-8-D-arginine vasopressin (dDAVP) induced the PARylation of total proteins, associated with an increase in the cleavage of PARP-1 and cleaved caspase-3 expression. By inhibiting PARP-1 with siRNA, the abundance of dDAVP-induced AQP2 mRNA and protein was significantly diminished. In contrast, despite a substantial decrease in PARylation, the PARP-1 inhibitor (PJ34) had no effect on the dDAVP-induced regulation of AQP2 expression. The findings suggest that PARP-1 protein expression itself, and not PARP-1-mediated PARylation, is necessary for dDAVP-regulated AQP2 expression. Bioinformatic analysis revealed that 408 proteins interact with PARP-1 in the collecting duct (CD) cells of the kidney. Among them, the signaling pathway of the vasopressin V2 receptor was identified for 49 proteins. In particular, ß-catenin, which is phosphorylated at Ser552 by dDAVP, was identified as the PARP-1-interacting protein. A significant decrease of ß-catenin phosphorylation (Ser552) in response to dDAVP was associated with siRNA-mediated PARP-1 knockdown. Taken together, PARP-1 is likely to play a role in vasopressin-induced AQP2 expression by interacting with ß-catenin in renal CD cells.NEW & NOTEWORTHY The poly(ADP-ribose) polymerase (PARP) family catalyzes poly(ADP-ribosylation) (PARylation), which is one of the posttranslational modifications of largely undetermined physiological significance. This study investigated the role of PARP-1, the most prevalent member of the PARP family, in the vasopressin-responsive expression of aquaporin-2 (AQP2). The results demonstrated that PARP-1 protein expression itself, and not PARP-1-mediated PARylation, is necessary for dDAVP-regulated AQP2 expression. ß-Catenin, which is phosphorylated at Ser552 by dDAVP, was identified as the PARP-1-interacting protein.

Exposure to fluoride exacerbates the cognitive deficit of diabetic patients living in areas with endemic fluorosis, as well as of rats with type 2 diabetes induced by streptozotocin via a mechanism that may involve excessive activation of the poly(ADP ribose) polymerase-1/P53 pathway.

Epidemiology has shown that fluoride exposure is associated with the occurrence of diabetes. However, whether fluoride affects diabetic encephalopathy is unclear. Elderly diabetic patients in areas with endemic (n = 169) or no fluorosis (108) and controls (85) underwent Montreal Cognitive Assessment. Sprague-Dawley rats receiving streptozotocin and/or different fluoride doses were examined for spatial learning and memory, brain morphology, blood-brain barrier, fasting blood glucose and insulin. Cultured SH-SY5Y cells were treated with 50 mM glucose and/or low- or high-dose fluoride, and P53-knockdown or poly-ADP-ribose polymerase-1 (PARP-1) inhibition. The levels of PARP-1, P53, poly-ADP-ribose (PAR), apoptosis-inducing factor (AIF), and phosphorylated-histone H2A.X (ser139) were measured by Western blotting. Reactive oxygen species (ROS), 8-hydroxydeguanosine (8-OHdG), PARP-1 activity, acetyl-P53, nicotinamide adenine dinucleotide (NAD+), activities of mitochondrial hexokinase1 (HK1) and citrate synthase (CS), mitochondrial membrane potential and apoptosis were assessed biochemically. Cognition of diabetic patients in endemic fluorosis areas was poorer than in other regions. In diabetic rats, fasting blood glucose, insulin resistance and blood-brain barrier permeability were elevated, while spatial learning and memory and Nissl body numbers in neurons declined. In these animals, expression and activity of P53 and PARP-1 and levels of NAD+, PAR, ROS, 8-OHdG, p-histone H2A.X (ser139), AIF and apoptosis content increased; whereas mitochondrial HK1 and CS activities and membrane potential decreased. SH-SY5Y cells exposed to glucose exhibited changes identical to diabetic rats. The changes in diabetic rats and cells treated with glucose were aggravated by fluoride. P53-knockout or PARP-1 inhibition mitigated the effects of glucose with/without low-dose fluoride. Elevation of diabetic encephalopathy was induced by exposure to fluoride and the underlying mechanism may involve overactivation of the PARP-1/P53 pathway.

RediScore: Prospective validation of a pipeline for homologous recombination deficiency analysis.

Tumors harboring homologous recombination deficiency (HRD) are considered optimal candidates for poly(ADP-ribose) polymerase 1 (PARP) inhibitor treatment. Such deficiency can be detected by analyzing breast cancer type (BRCA)1/2 gene mutations, as well as mutations in other genes of the homologous recombination pathway. The algorithmic measurement of the HRD effect by identifying genomic instability (GI) has been used as biomarker. As compared with the direct measurement of somatic gene alterations, this approach increases the number of patients who could benefit from PARP inhibitor treatment. In the present study, the performance of the Oncoscan CNV assay, accompanied by appropriate bioinformatic algorithms, was evaluated for its performance in GI calculation and was compared with that of a validated next-generation sequencing (NGS) test (myChoice HRD test). In addition, the clinical utility of the GI score (GIS) and BRCA1/2 tumor analysis were investigated in a cohort of 444 patients with ovarian cancer. For that reason, single nucleotide polymorphism (SNP) arrays and appropriate bioinformatics algorithms were used to calculate GIS in 29 patients with ovarian cancer with known GIS status using a validated NGS test. Furthermore, BRCA1/2 analysis results were compared between the aforementioned assay and the amplicon-based Oncomine™ BRCA Research Assay. BRCA1/2 analysis was performed in 444 patients with ovarian cancer, while GIS was calculated in 175 BRCA1/2-negative cases. The bioinformatics algorithm developed for GIS calculation in combination with NGS BRCA1/2 analysis (RediScore), and the OncoscanR pipeline exhibited a high overall agreement with the validated test (93.1%). In addition, the Oncomine NGS assay had a 100% agreement with the validated test. The BRCA1/2 mutation frequency was 26.5% in the examined patients with ovarian cancer. GIS was positive in 40% of the BRCA1/2-negative cases. The RediScore bioinformatics algorithm developed for GIS calculation in combination with NGS BRCA1/2 analysis is a viable and effective approach for HRD calculation in patients with ovarian cancer, offering a positive prediction for PARP inhibitor responsiveness in 55% of the patients.

FUS RRM regulates poly(ADP-ribose) levels after transcriptional arrest and PARP-1 activation on DNA damage.

PARP-1 activation at DNA damage sites leads to the synthesis of long poly(ADP-ribose) (PAR) chains, which serve as a signal for DNA repair. Here we show that FUS, an RNA-binding protein, is specifically directed to PAR through its RNA recognition motif (RRM) to increase PAR synthesis by PARP-1 in HeLa cells after genotoxic stress. Using a structural approach, we also identify specific residues located in the FUS RRM, which can be PARylated by PARP-1 to control the level of PAR synthesis. Based on the results of this work, we propose a model in which, following a transcriptional arrest that releases FUS from nascent mRNA, FUS can be recruited by PARP-1 activated by DNA damage to stimulate PAR synthesis. We anticipate that this model offers new perspectives to understand the role of FET proteins in cancers and in certain neurodegenerative diseases such as amyotrophic lateral sclerosis.