Olaparib en adyuvancia en cáncer de mama triple negativo / Olaparib as adjuvant therapy for the negative breast cancer

CONTEXTO CLÍNICO: El cáncer de mama continúa siendo una carga significativa para la salud, con consecuencias importantes en términos de enfermedad y mortalidad a nivel mundial. 2 En la actualidad, ha superado al cáncer de pulmón como el tipo de cáncer más diagnosticado y ocupa el quinto lugar como causa de mortalidad relacionada con el cáncer. Se estima que en 2020 hubo alrededor de 2,3 millones de casos nuevos (11,7% de todos los cánceres) y 685.000 muertes debido a esta enfermedad. 3 En los últimos años, la tasa de incidencia ha aumentado, estimándose que para el año 2040 aumentará en más del 40%, alcanzando aproximadamente tres millones de casos nuevos y un millón de muertes anuales. 3,4 En Argentina, los datos de 2020 reflejan una incidencia en mujeres mayores de 15 años de 105,9 por 100.000 habitantes. El cáncer de mama triple negativo (CMTN) es un subtipo agresivo que representa aproximadamente el 15-20% de todos los casos de cáncer de mama. Se caracteriza por la falta de expresión de los receptores de estrógeno, progesterona y del receptor 2 del factor de crecimiento epidérmico humano (HER2, su sigla del inglés human epidermal growth factor receptor 2). A diferencia del cáncer de mama con receptores hormonales positivos, el CMTN se diagnostica con mayor frecuencia en mujeres jóvenes premenopáusicas menores de 40 años. TECNOLOGÍA: El olaparib es un medicamento perteneciente a la clase de inhibidores la poli-adenosina difosfato ribosa polimerasa (PARP). Se encuentra disponible en forma de comprimidos con dosis de 100 y 150 mg, y se comercializa bajo el nombre comercial Lynparza®. 13 Este medicamento funciona bloqueando la capacidad de la PARP para reparar el ácido Desoxirribonucleico (ADN) dañado, lo que resulta en una acumulación de daño en las células cancerosas. En el caso de las mutaciones en BRCA, que ya presentan deficiencias en la reparación del ADN, la inhibición de PARP aumenta aún más la acumulación de daño y finalmente induce la muerte de las células cancerosas. OBJETIVO: El objetivo del presente informe es evaluar la evidencia disponible acerca de la eficacia, seguridad y aspectos relacionados a las políticas de cobertura del uso de olaparib adyuvante para el tratamiento de CMTN de alto riesgo de recurrencia. MÉTODOS: Se realizó una búsqueda en las principales bases de datos bibliográficas, en buscadores genéricos de internet, y financiadores de salud. Se priorizó la inclusión de revisiones sistemáticas (RS), ensayos clínicos controlados aleatorizados (ECAs), evaluaciones de tecnologías sanitarias (ETS), evaluaciones económicas, guías de práctica clínica (GPC) y políticas de cobertura de diferentes sistemas de salud. RESULTADOS: Se incluyeron: un ECA, un estudio de métodos mixtos, una ETS, una EE, cuatro GPC y 13 políticas de cobertura. CONCLUSIONES: Evidencia de alta calidad muestra que el olaparib versus cuidado usual en el tratamiento adyuvante de pacientes adultos con cáncer de mama triple negativo temprano de alto riesgo de recurrencia con mutaciones de línea germinal BRCA que recibieron tratamiento con quimioterapia neoadyuvante o adyuvante, produce un beneficio neto considerable porque produce un aumento de la sobrevida global y la sobrevida libre de progresión. No se observaron diferencias relevantes en la calidad de vida, pero sí se evidenció un aumento en los efectos adversos. Es importante señalar que no se encontró ningún estudio que comparara el olaparib con la capecitabina. Todas de las guías de práctica clínica relevadas, incluída la argentina, recomiendan olaparib para el tratamiento adyuvante de pacientes adultos con cáncer de mama temprano de alto riesgo negativo para receptor HER2 (incluyendo el subtipo cáncer de mama triple negativo) con mutaciones de línea germinal BRCA que recibieron tratamiento con quimioterapia neoadyuvante o adyuvante. La mayoría de los financiadores en países de altos ingresos ofrecen cobertura para el uso de olaparib como tratamiento adyuvante en pacientes con cáncer de mama triple negativo temprano y alto riesgo de recurrencia que ya hayan recibido neoadyuvancia o adyuvancia. En el caso de los financiadores latinoamericanos, no se menciona o no se especifica la indicación o cobertura específica de este medicamento para dicho grupo de pacientes. En lo que respecta a las evaluaciones económicas, un estudio que incluyó pacientes con cáncer de mama triple negativo en Estados Unidos mostró que el tratamiento adyuvante con olaparib resultó costo efectivo para mujeres con cáncer de mama en estadio temprano y mutación BRCA. No se encontró otra evidencia económica en el mundo ni en Argentina, por lo que la costo efectividad y el impacto presupuestario local de este tratamiento son inciertos.

Eficacia y seguridad de olaparib como terapia de mantenimiento en mujeres adultas con cáncer de ovario epitelial avanzado, de trompas de falopio o peritoneal primario con mutación de brca de línea germinal o somática que presentan respuesta completa o parcial a la quimioterapia basada en platino de primera línea que no recibieron bevacizumab / Efficacy and safety of olaparib as maintenance therapy in adult women with somatic or germline BRCA-mutated advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer who have a complete or partial response to first-line platinum-based chemotherapy who did not receive bevacizumab

ANTECEDENTES: En el marco de la metodología ad hoc para evaluar solicitudes de tecnologías sanitarias, aprobada mediante Resolución de Instituto de Evaluación de Tecnologías en Salud e Investigación N° 111-IETSI-ESSALUD-2021, se ha elaborado el presente dictamen, el cual expone la evaluación de la eficacia y seguridad de olaparib como terapia de mantenimiento en mujeres adultas con cáncer de ovario epitelial avanzado, de trompas de Falopio o peritoneal primario con mutación de BRCA de línea germinal o somática que presentan respuesta completa o parcial a la quimioterapia basada en platino de primera línea que no recibieron bevacizumab. Así, el Dr. Miguel Ticona Castro, médico oncólogo del Hospital Nacional Edgardo Rebagliati Martins, siguiendo la Directiva N° 003-IETSI-ESSALUD-2016, envía al Instituto de Evaluación de Tecnologías en Salud e Investigación ­ IETSI, la solicitud de uso fuera del petitorio del producto olaparib. METODOLOGÍA: Se realizó una búsqueda bibliográfica exhaustiva en las bases de datos PubMed, The Cochrane Library y LILACS. Asimismo, se realizó una búsqueda manual dentro de las páginas web pertenecientes a grupos que realizan evaluaciones de tecnologías sanitarias (ETS) y guías de práctica clínica (GPC), incluyendo la National Institute for Health and Care Excellence (NICE), Canadian Agency for Drugs and Technologies in Health (CADTH), Scottish Medicines Consortium (SMC), Instituto de Calidad y Eficiencia en la Atención de la Salud (IQWiG, por sus siglas en alemán), Haute Autorité de Santé (HAS), el Instituto de Evaluación Tecnológica en Salud (IETS), el Instituto de Efectividad Clínica y Sanitaria (IECS), Comissão Nacional de Incorporação de Tecnologias no Sistema Único de Saúde (CONITEC), la Base Regional de Informes de Evaluación de Tecnologías en Salud de las Américas (BRISA), el Instituto de Evaluación de Tecnologías en Salud e Investigación (IETSI), Centro Nacional de Excelencia Tecnológica en Salud (CENETEC) , Agency for Healthcare Research and Quality (AHRQ), Scottish Intercollegiate Guidelines Network (SIGN), Guidelines International Network (GIN), National Health and Medical Research Council (NHMRC), New Zealand Guidelines Group (NZGG), European Society for Medical Oncology (ESMO), National Comprehensive Cancer Network (NCCN). Además, se realizó una búsqueda de GPC de las principales sociedades o instituciones especializadas en oncología y ginecología oncológica, tales como: la American Society of Clinical Oncology (ASCO), Sociedad Española de Oncología Médica (SEOM), y la International Federation of Gynecology and Obstetrics (FIGO). Finalmente, se realizó una búsqueda adicional en la página web de registro de ensayos clínicos (EC) www.clinicaltrials.gov, para identificar EC en curso o que no hayan sido publicados aún. La búsqueda de literatura se limitó a GPC, ETS, revisiones sistemáticas (RS) con metaanálisis de ECA de fase III y ECA de fase III. RESULTADOS: Luego de la búsqueda bibliográfica (hasta diciembre de 2021), se incluyeron 5 GPC desarrolladas por la NCCN (National Comprehensive Cancer Network 2021), la ASCO (Tew et al. 2020), la Cancer Care Ontario (Hirte et al. 2021), la ESMO (Colombo et al. 2019) y la SEOM (Redondo et al. 2021); así como 3 ETS realizadas por CADTH, NICE e IQWiG (Institute for Quality and Efficiency in Health Care 2019, The CADTH pan- Canadian Oncology Drug Review (pCODR) 2019, The National Institute for Health and Care Excellence 2019), y un ensayo clínico aleatorizado (ECA) de fase III de doble ciego denominado SOLO-1 (NCT01844986) con tres publicaciones de un análisis interino (Moore et al. 2018), de calidad de vida (Friedlander et al. 2021) y una con seguimiento hasta cinco años de seguimiento (Banerjee et al. 2021). CONCLUSIÓN: Por lo expuesto, el Instituto de Evaluación de Tecnologías en Salud e Investigación aprueba el uso de olaparib como terapia de mantenimiento en mujeres adultas con cáncer de ovario epitelial avanzado, de trompas de Falopio o peritoneal primario con mutación de BRCA de línea germinal o somática que presentan respuesta completa o parcial a la quimioterapia basada en platino de primera línea que no recibieron bevacizumab. La vigencia del presente dictamen es de un año y se debe asegurar un sistema de farmacovigilancia intensiva de los pacientes que lleguen a usar olaparib, según lo establecido en el Anexo N° 1. Asimismo, la continuación de dicha aprobación estará sujeta a la evaluación de los resultados obtenidos y de mayor evidencia que pueda surgir en el tiempo.

The role of novel poly (ADP-ribose) inhibitors in the treatment of locally advanced and metastatic Her-2/neu negative breast cancer with inherited germline BRCA1/2 mutations. A review of the literature.

The use of the PARP inhibitors (PARPi) in the treatment of breast cancer (BC) with germine mutations has evolved over the years, and further research has been done in order to broaden the horizon of this treatment strategy. Therefore the aim of this paper is to review the efficiency of PARPi in the treatment of BRCA 1/2-mutated locally advanced and metastatic Her-2/net negative BC mentioning their side effects, mechanism of resistance and future directions. Inhibition of PARP transforms single-strand breaks into double-strand breaks (DBS), the accumulation of the latter causing cell death (cell apoptosis). The Olympia AD phase III trial demonstrated a statistically significant progression-free survival rate (PFS) when using the PARPi olaparib in metastatic BC with germline BRCA1/2 mutations without any benefit of the overall survival rate. PARPi therapy is associated with acceptable responsive rates and progression-free survival rates in locally advanced and metastatic BRCA1/2 associated BC through mechanisms that enhance and increase the sensitivity to chemotherapeutic or target agents as they induce a synthetic lethality and cell apoptosis. The side effects are not significant, the most adverse effects being related to the hematological and gastrointestinal systems. Olaparib is currently approved in the first-line treatment of BRCA1/2 mutated Her-2/neu negative metastatic BC at an oral dose of 300 mg twice daily, while Talazoparib represents a category one recommendation in locally advanced and metastatic Her-2/neu negative BC in women with central nervous system metastases.

Inhibition of PARP activity improves therapeutic effect of ARPE-19 transplantation in RCS rats through decreasing photoreceptor death.

Photoreceptor (PR) dysfunction or death is the key pathological change in retinal degeneration (RD). The death of PRs might be due to a primary change in PRs themselves or secondary to the dysfunction of the retinal pigment epithelium (RPE). Poly(ADP-ribose) polymerase (PARP) was reported to be involved in primary PR death, but whether it plays a role in PR death secondary to RPE dysfunction has not been determined. To clarify this question and develop a new therapeutic approach, we studied the changes in PAR/PARP in the RCS rat, a RD model, and tested the effect of PARP intervention when given alone or in combination with RPE cell transplantation. The results showed that poly(ADP-ribosyl)ation of proteins was increased in PRs undergoing secondary death in RCS rats, and this result was confirmed by the observation of similar changes in sodium iodate (SI)-induced secondary RD in SD rats. The increase in PAR/PARP was highly associated with increased apoptotic PRs and decreased visual function, as represented by lowered b-wave amplitudes on electroretinogram (ERG). Then, as we expected, when the RCS rats were treated with subretinal injection of the PARP inhibitor PJ34, the RD process was delayed. Furthermore, when PJ34 was given simultaneously with subretinal ARPE-19 cell transplantation, the therapeutic effects were significantly improved and lasted longer than those of ARPE-19 or PJ34 treatment alone. These results provide a potential new approach for treating RD.

PARPs and PAR as novel pharmacological targets for the treatment of stress granule-associated disorders.

Among the post-translational modifications, ADP-ribosylation has been for long time the least integrated in the scheme of the structural protein modifications affecting physiological functions. In spite of the original findings on bacterial-dependent ADP-ribosylation catalysed by toxins such as cholera and pertussis toxin, only with the discovery of the poly-ADP-ribosyl polymerase (PARP) family the field has finally expanded and the role of ADP-ribosylation has been recognised in both physiological and pathological processes, including cancer, infectious and neurodegenerative diseases. This is now a rapidly expanding field of investigation, centred on the role of the different PARPs and their substrates in various diseases, and on the potential of PARP inhibitors as novel pharmacological tools to be employed in relevant pathological context. In this review we analyse the role that members of the PARP family and poly-ADP-ribose (PAR; the product of PARP1 and PARP5a activity) play in the processes following the exposure of cells to different stresses. The cell response that arises following conditions such as heat, osmotic, oxidative stresses or viral infection relies on the formation of stress granules, which are transient cytoplasmic membrane-less structures, that include untranslated mRNA, specific proteins and PAR, this last one serving as the "collector" of all components (that bind to it in a non-covalent manner). The resulting phenotypes are cells in which translation, intracellular transport or pro-apoptotic pathways are reversibly inhibited, for the time the given stress holds. Interestingly, the formation of defective stress granules has been detected in diverse pathological conditions including neurological disorders and cancer. Analysing the molecular details of stress granule formation under these conditions offers a novel view on the pathogenesis of these diseases and, as a consequence, the possibility of identifying novel drug targets for their treatment.

Novel Targets and Precision Medicine for Prostate Cancer-Part 2: Tumor Profiling and Personalized Therapy in Patients With Castration-Resistant Prostate Cancer.

Despite advances in the treatment of castration-resistant prostate cancer (CRPC), options remain limited and non-curative; thus, prostate cancer remains one of the deadliest cancers in men. The discovery of novel therapeutic targets is needed to improve outcomes for men with metastatic CRPC. Precision/personalized medicine creates new opportunities to discover these targets. With an increase in the use of next-generation sequencing and tumor profiling, potentially clinically relevant tumor mutations are being identified. Here, we review the current use of and future direction for genetic testing and tumor profiling in patients with metastatic CRPC.

Abnormal heart rate variability and atrial fibrillation after aortic surgery / Variabilidade anormal da frequência cardíaca e fibrilação atrial após cirurgia aórtica

Introduction: Complete denervation of transplanted heart exerts protective effect against postoperative atrial fibrillation; various degrees of autonomic denervation appear also after transection of ascending aorta during surgery for aortic aneurysm. Objective: This study aimed to evaluate if the level of cardiac denervation obtained by resection of ascending aorta could exert any effect on postoperative atrial fibrillation incidence. Methods: We retrospectively analysed the clinical records of 67 patients submitted to graft replacement of ascending aorta (group A) and 132 with aortic valve replacement (group B); all episodes of postoperative atrial fibrillation occurred during the 1-month follow-up have been reported. Heart Rate Variability parameters were obtained from a 24-h Holter recording; clinical, echocardiographic and treatment data were also evaluated. Results: Overall, 45% of patients (group A 43%, group B 46%) presented at least one episode of postoperative atrial fibrillation. Older age (but not gender, abnormal glucose tolerance, ejection fraction, left atrial diameter) was correlated with incidence of postoperative atrial fibrillation. Only among a subgroup of patients with aortic transection and signs of greater autonomic derangement (heart rate variability parameters below the median and mean heart rate over the 75th percentile), possibly indicating more profound autonomic denervation, a lower incidence of postoperative atrial fibrillation was observed (22% vs. 54%). Conclusion: Transection of ascending aorta for repair of an aortic aneurysm did not confer any significant protective effect from postoperative atrial fibrillation in comparison to patients with intact ascending aorta. It could be speculated that a limited and heterogeneous cardiac denervation was produced by the intervention, creating an eletrophysiological substrate for the high incidence of postoperative atrial fibrillation observed. .

Introdução: Denervação completa do coração transplantado exerce efeito protetor contra a fibrilação atrial no pós-operatório; vários graus de denervação autonômica aparecem também após a transecção da aorta ascendente durante a cirurgia de aneurisma da aorta. Objetivo: Este estudo teve como objetivo avaliar se o nível de denervação cardíaca obtida por ressecção da aorta ascendente poderia exercer algum efeito sobre a incidência de fibrilação atrial no pós-operatório. Métodos: Foram analisados retrospectivamente os prontuários de 67 pacientes submetidos a enxerto de substituição de aorta torácica (grupo A) e 132 com a substituição da valva aórtica (grupo B). Foram relatados todos os episódios de fibrilação atrial pós-operatória ocorridos durante 1 mês de seguimento. Parâmetros de variabilidade da frequência cardíaca foram obtidos a partir de 24 h de gravação do Holter; dados clínicos, ecocardiográficos e de tratamento também foram avaliados. Resultados: No geral, 45% dos pacientes (grupo A 43%, grupo B 46%) apresentaram pelo menos um episódio de fibrilação atrial no pós-operatório. Idade mais avançada (mas não gênero, tolerância à glicose anormal, fração de ejeção, diâmetro do átrio esquerdo) foi correlacionada com a incidência de fibrilação atrial pós-operatória. Apenas em um subgrupo de pacientes com transecção aórtica e sinais de maior desarranjo autonômico (parâmetros de variabilidade da frequência cardíaca abaixo da mediana e a média de frequência cardíaca acima do percentil 75), indicando possivelmente denervação autonômica mais profunda, foi observada menor incidência de fibrilação atrial pós-operatória (22% vs. 54%). Conclusão: Transecção da aorta ascendente para correção de um aneurisma da aorta não confere qualquer efeito protetor significativo de fibrilação atrial no pós-operatório em comparação com pacientes com aorta ascendente intacta. Pode-se especular que uma denervação cardíaca limitada e heterogênea foi produzida pela ...

Protective effect of nicotinamide on high glucose/palmitate-induced glucolipotoxicity to INS-1 beta cells is attributed to its inhibitory activity to sirtuins.

This study was initiated to determine whether the protective effect of nicotinamide (NAM) on high glucose/palmitate (HG/PA)-induced INS-1 beta cell death was due to its role as an anti-oxidant, nicotinamide dinucleotide (NAD+) precursor, or inhibitor of NAD+-consuming enzymes such as poly (ADP-ribose) polymerase (PARP) or sirtuins. All anti-oxidants tested were not protective against HG/PA-induced INS-1 cell death. Direct supplementation of NAD+ or indirect supplementation through NAD+ salvage or de novo pathway did not protect the death. Knockdown of the NAD+ salvage pathway enzymes such as nicotinamide phosphoribosyl transferase (NAMPT) or nicotinamide mononucleotide adenyltransferase (NMNAT) did not augment death. On the other hand, pharmacological inhibition or knockdown of PARP did not affect death. However, sirtinol as an inhibitor of NAD-dependant deacetylase or knockdown of SIRT3 or SIRT4 significantly reduced the HG/PA-induced death. These data suggest that protective effect of NAM on beta cell glucolipotoxicity is attributed to its inhibitory activity on sirtuins.

Poly(ADP-ribosylation) regulates chromatin organization through histone H3 modification and DNA methylation of the first cell cycle of mouse embryos.

We examined the roles of poly(ADP-ribosylation) in chromatin remodeling during the first cell cycle of mouse embryos. Drug-based inhibition of poly(ADP-ribosylation) by a PARP inhibitor, PJ-34, revealed up-regulation of dimethylation of histone H3 at lysine 4 in male pronuclei and down-regulation of dimethylation of histone H3 at lysine 9 (H3K9) and lysine 27 (H3K27). Association of poly(ADP-ribosylation) with histone modification was suggested to be supported by the interaction of Suz12, a histone methyltransferase in the polycomb complex, with Parp1. PARP activity was suggested to be required for a proper localization and maintenance of Suz12 on chromosomes. Notably, DNA methylation level of female pronuclei in one-cell embryos was robustly decreased by PJ-34. Electron microscopic analysis showed a frequent appearance of unusual electron-dense areas within the female pronuclei, implying the disorganized and hypercondensed chromatin ultrastructure. These results show that poly(ADP-ribosylation) is important for the integrity of non-equivalent epigenetic dynamics of pronuclei during the first cell cycle of mouse embryos.

Emerging targeted therapies in triple-negative breast cancer.

Standard chemotherapy regimens can prove effective for patients with early triple-negative breast cancer (TNBC); however, patients with advanced disease typically respond poorly and rapidly progress, and the outcome is poor. New targeted therapies are therefore an urgent unmet medical need for this patient population. Translational and clinical studies into new TNBC treatments have been facilitated by the increased understanding of the aberrant signal transduction pathways regulating growth and survival and the development of chemoresistance in TNBC. Some of the established targeted agents that have been approved in other indications may prove beneficial to patients with TNBC; however, in the absence of approved targeted agents for the treatment of TNBC, most new agents remain experimental. Increased understanding of molecular profiles of TNBC subtypes is likely to improve therapeutic strategies with targeted agents. Novel strategies have reached clinical evaluation in patients with TNBC, including targeting angiogenesis vascular endothelial growth factor and proliferation signalling (receptor tyrosine kinases and mammalian target of rapamycin). Aggressive TNBCs have been found to associate closely with BRCA1 mutation or dysregulation. The recent development of new investigational agents targeting DNA repair, either directly with poly(adenosine disphosphate-ribose) polymerase inhibitors or indirectly through DNA-binding or DNA-damage potentiation, is a major focus of current clinical studies. These and other targeted therapies represent a new approach to TNBC therapy.

Treatment with Actovegin® improves sensory nerve function and pathology in streptozotocin-diabetic rats via mechanisms involving inhibition of PARP activation.

BACKGROUND: Diabetic neuropathy is one of the most severe complications of diabetes, affecting approximately one-third of diabetic patients. We investigated the potential neuroprotective effect of Actovegin®, a deproteinized hemoderivative of calf blood, in an animal model of diabetic neuropathy. METHODS: A single intravenous injection of streptozotocin (STZ, 55 mg/kg) was used to induce experimental diabetes in male Sprague-Dawley rats. Actovegin® (200 or 600 mg/kg) was administered intraperitoneally from day 11 to day 40 post-STZ exposure. N-acetylcysteine (NAC) was used as a positive control and was added to drinking water (0.2 g/l) from day 2 until day 40. Measurements to assess efficacy included sensory nerve conduction velocity (SNCV), intraepidermal nerve fiber density (IENFD), and poly(ADP-ribose) content. RESULTS: A decrease (35%) in sensory nerve conduction velocity (SNCV) was seen in STZ-induced diabetic rats from day 10 post-STZ administration and persisted at days 25 and 39. At study completion (day 41), a decrease (32%) in intraepidermal nerve fiber density (IENFD) was found in hind-paw skin biopsies from STZ-rats. Reduced SNCV and IENFD were significantly ameliorated by both doses of Actovegin®. More-over, 600 mg/kg Actovegin® markedly decreased poly(ADP-ribose) polymerase (PARP) activity in sciatic nerves from STZ-diabetic rats as assessed by poly(ADP-ribose) content. CONCLUSION: Actovegin® improved several para-meters of experimental diabetic neuropathy via mechanisms involving suppression of PARP activation, providing a rationale for treatment of this disease in humans.

Cellular toxicity of nicotinamide metabolites.

There are almost 100 different substances called uremic toxins. Nicotinamide derivatives are known as new family of uremic toxins. These uremic compounds play a role in an increased oxidative stress and disturbances in cellular repair processes by inhibiting poly (ADP-ribose) polymerase activity. New members of this family were discovered and described. Their toxic properties were a subject of recent studies. This study evaluated the concentration of 4-pyridone-3-carboxamid-1-ß-ribonucleoside-triphosphate (4PYTP) and 4-pyridone-3-carboxamid-1-ß-ribonucleoside-monophosphate (4PYMP) in erythrocytes of patients with chronic renal failure. Serum and red blood cells were collected from chronic renal failure patients on conservative treatment, those treated with hemodialysis, and at different times from those who underwent kidney transplantation. Healthy volunteers served as a control group. Nicotinamide metabolites were determined using liquid chromatography with mass spectrometry based on originally discovered and described method. Three novel compounds were described: 4-pyridone-3-carboxamid-1-ß-ribonucleoside (4PYR), 4PYMP, and 4PYTP. 4PYR concentration was elevated in the serum, whereas 4PYMP and 4PYTP concentrations were augmented in erythrocytes of dialysis patients. Interestingly, concentrations of these compounds were less elevated during the treatment with erythropoietin-stimulating agents (ESAs). After successful kidney transplantation, concentrations of 4PYR and 4PYMP normalized according to the graft function, whereas that of 4PYTP was still elevated. During the incubation of erythrocytes in the presence of 4PYR, concentration of 4PYMP rose very rapidly while that of 4PYTP increased slowly. Therefore, we hypothesized that 4PYR, as a toxic compound, was actively absorbed by erythrocytes and metabolized to the 4PYMP and 4PYTP, which may interfere with function and life span of these cells.

[Alkylating agents]. / Agents alkylants.

With the approval of mechlorethamine by the FDA in 1949 for the treatment of hematologic malignancies, alkylating agents are the oldest class of anticancer agents. Even though their clinical use is far beyond the use of new targeted therapies, they still occupy a major place in specific indications and sometimes represent the unique option for the treatment of refractory diseases. Here, we are reviewing the major classes of alkylating agents and their mechanism of action, with a particular emphasis for the new generations of alkylating agents. As for most of the chemotherapeutic agents used in the clinic, these compounds are derived from natural sources. With a complex but original mechanism of action, they represent new interesting alternatives for the clinicians, especially for tumors that are resistant to conventional DNA damaging agents. We also briefly describe the different strategies that have been or are currently developed to potentiate the use of classical alkylating agents, especially the inhibition of pathways that are involved in the repair of DNA lesions induced by these agents. In this line, the development of PARP inhibitors is a striking example of the recent regain of interest towards the "old" alkylating agents.

Iduna protects the brain from glutamate excitotoxicity and stroke by interfering with poly(ADP-ribose) polymer-induced cell death.

Glutamate acting on N-methyl-D-aspartate (NMDA) receptors induces neuronal injury following stroke, through activation of poly(ADP-ribose) polymerase-1 (PARP-1) and generation of the death molecule poly(ADP-ribose) (PAR) polymer. Here we identify Iduna, a previously undescribed NMDA receptor-induced survival protein that is neuroprotective against glutamate NMDA receptor-mediated excitotoxicity both in vitro and in vivo and against stroke through interfering with PAR polymer-induced cell death (parthanatos). Iduna's protective effects are independent and downstream of PARP-1 activity. Iduna is a PAR polymer-binding protein, and mutation at the PAR polymer binding site abolishes the PAR binding activity of Iduna and attenuates its protective actions. Iduna is protective in vivo against NMDA-induced excitotoxicity and middle cerebral artery occlusion-induced stroke in mice. To our knowledge, these results define Iduna as the first known endogenous inhibitor of parthanatos. Interfering with PAR polymer signaling could be a new therapeutic strategy for the treatment of neurologic disorders.

Poly(ADP-ribose)-dependent regulation of Snail1 protein stability.

Snail1 is a master regulator of the epithelial-mesenchymal transition (EMT) and has been implicated in key tumor biological processes such as invasion and metastasis. It has been previously shown that poly(ADP-ribose) polymerase-1 (PARP-1) knockdown, but not PARP inhibition, downregulates the expression of Snail1. In this study we have characterized a novel regulatory mechanism controlling Snail1 protein expression through poly(ADP-ribosyl)ation. The effect is not only limited to repression of Snail1 transcription but also to downregulated Snail1 protein stability. PARP-1 (but not PARP-2) poly(ADP) ribosylates Snail1, both in vivo and in vitro, and interacts with Snail1, an association that is sensitive to PARP inhibitors. PARP inhibition has also clear effects on EMT phenotype of different tumor cells, including Snail1 downregulation, E-cadherin upregulation, decreased cell elongation and invasiveness. Therefore, this study reveals a new regulatory mechanism of Snail1 activation through poly(ADP-ribosyl)ation with consequences in malignant transformation through EMT.

Activation of cell death mediated by apoptosis-inducing factor due to the absence of poly(ADP-ribose) glycohydrolase.

We previously demonstrated that the absence of poly(ADP-ribose) glycohydrolase (PARG) led to increased cell death following DNA-damaging treatments. Here, we investigated cell death pathways following UV treatment. Decreased amounts of PARG-null embryonic trophoblast stem (TS) cells were observed following doses of 10-100 J/m2 as compared to wild-type cells. In wild-type cells, caspase-cleaved poly(ADP-ribose) polymerase-1 (PARP-1) and activated caspase-3 were detected 12-24 h after UV treatment. Surprisingly, both were detected at decreased levels only after 24 h in PARG-null TS cells, indicating a decreased level and delayed presence of caspase-mediated events. Further, a time- and dose-dependent accumulation of poly(ADP-ribose) (PAR) levels after UV was observed in PARG-null TS cells and not in wild-type cells. Determination of the levels of nicotinamide adenine dinucleotide (NAD+), the substrate for PAR synthesis and a coenzyme in cellular redox reactions, demonstrated a UV dose-dependent decrease in the level of NAD+ in wild-type cells, while NAD+ levels in PARG-null TS cells remained at higher levels. This indicates no depletion of NAD+ in PARG-null TS cells following increased levels of PAR. Lastly, cell death mediated by apoptosis-inducing factor (AIF) was analyzed because of its dependence on increased PAR levels. The results demonstrate nuclear AIF translocation only in PARG-null TS cells, which demonstrates the presence of AIF-mediated cell death. Herein, we provide compelling evidence that the absence of PARG leads to decreased caspase-3 activity and the specific activation of AIF-mediated cell death. Therefore, the absence of PARG may provide a strategy for specifically inducing an alternative apoptotic pathway.

New drugs for breast cancer.

Recently there have been significant advances in rational drug design for the treatment of breast cancer, especially in the area of targeted drug therapy. These include drugs which target the HER2 receptor and angiogenesis and the novel class of drug the PARP inhibitors. Some of these agents, for example, trastuzumab used in the treatment of HER2 positive breast cancer are already established as the standard of care. However, the duration of adjuvant trastuzumab, whether to continue it beyond progression in metastatic disease and the mechanism for developing trastuzumab resistance, remain to be determined. There is also much still to be learnt regarding other targeted therapies; the efficacy of different agents, the optimal duration of use and combination of therapies. Many of these agents are already in clinical trials, the results of which are likely to change clinical practice.

New advances in ovarian cancer.

Epithelial ovarian cancer is the leading cause of death from gynecologic malignancy in the United States, with approximately 15,000 deaths per year. Platinum/taxane doublets have long been considered the standard treatment regimen for advanced-stage disease; however, recent studies have sought to improve on the outcome from this therapy. Intraperitoneal (IP) chemotherapy has been shown to yield superior progression-free survival (PFS) and overall survival (OS); however, logistical problems and toxicities have limited more widespread adoption. Recent studies have also suggested that a "dose-dense" schedule of paclitaxel in combination with carboplatin may result in improved outcomes, and the impact of biological therapies in the first-line setting is under active investigation. In the setting of recurrent disease, preliminary results suggest that novel doublet regimens such as carboplatin and pegylated liposomal doxorubicin may have similar activity to standard platinum/taxane doublets while carrying a reduced risk of allergic reactions. Additionally, targeted therapy remains an active area of investigation, with evidence of activity from agents such as PARP inhibitors, anti-angiogenics, and PI3 kinase inhibitors. Here, we review recent advances in our understanding of ovarian cancer and its treatment in both the newly diagnosed and recurrent settings.