Academic literature on the topic 'Farmacologic resistance'

Acute rhinitis and acute rhinosinusitis (ARS) have viral etiology in the most of cases, and their therapy is aimed at alleviating clinical symptoms and preventing new episodes. The indications for antibiotic therapy are severe bacterial ARS, ARS with complications, and recurrent bacterial ARS. Such a categorical approach is due to the increase of antibiotic resistance, which leads to the popularization of efficient phytotherapy. Modern herbal medical products comply with general recommendation and standards of efficacy, safety and quality, and their effectiveness has been proven in clinical trials along with synthetic drugs. In acute upper respiratory tract infections, herbal medical drugs stimulate the immune system, relieve clinical symptoms, and improve the patient’s quality of life. A significant emphasis in phytotherapy is given to complex drugs synthesized on the basis of phytoneering. One of such remedies is the herbal medicinal product containing the different parts of 5 medicinal herbs: Gentian root (Gentianae radix), Primrose flowers (with calyx) (Primulae flos (cum calycibus)), Common sorrel herb (Rumicis herba), Elder flowers (Sambuci flos) and Vervain herb (Verbenae herba). This herbal medicinal product shows secretolytic, secretomotor, antiinflammatory, antiviral and mild antibacterial farmacological effects. The article provides an analysis of studies in vitro and in vivo proving the anti-inflammatory effect of Sinupret®, its potentiating effect on nasal mucosa mucociliary transport as well as efficacy and safety in patients with rhinosinusitis.

OBJECTIVE: To introduce troglitazone (CS-045, Rezulin), a new oral antidiabetic agent and discuss its pharmacology, therapeutics, pharmacokinetics, dosing guidelines, adverse effects, drug interactions, and clinical efficacy. DATA SOURCES: A MEDLINE database search was completed to identify relevant articles including reviews, recent studies and abstracts, and data from Parke-Davis. STUDY SELECTION: Due to the small number of published human studies available, some data are derived from animal studies and abstracts of human studies. Studies and abstracts chosen summarize the clinical action of troglitazone in healthy volunteers, in subjects with impaired glucose tolerance, and in patients with diabetes mellitus. Three of the six published human studies used subjects in a placebo-controlled, multicenter, randomized environment (type 2 diabetic patients or obese subjects with insulin resistance). DATA EXTRACTION: All clinical trials available, including unpublished reports, were reviewed. DATA SYNTHESIS: Troglitazone is the first member of a new class of medications, the thiazolidinediones, to be approved for clinical use. Troglitazone increases insulin sensitivity in skeletal muscle and in hepatic and adipose tissue. It has been shown to decrease hepatic glucose output while having no effect on stimulating insulin secretion from the pancreatic β-cells. Its metabolic effects decrease fasting and postprandial hyperglycemia, insulin concentrations, and triglyceride concentrations, while increasing high-density lipoprotein concentrations. There is some evidence, based on short-term trials, that troglitazone causes only minimal decreases in glycosylated hemoglobin A1C (HbA1C) concentrations. Data suggest that troglitazone decreases impaired glucose tolerance in nondiabetic obese subjects and leads to a reduction in both systolic and diastolic blood pressure in hypertensive type 2 diabetes mellitus patients. Troglitazone has a mild adverse effect profile, with rare instances of abnormal liver function tests. CONCLUSIONS: Troglitazone appears to be a safe, effective, and useful new agent in the treatment of insulin-requiring type 2 diabetes mellitus patients, although its HbA1C-lowering effects have been minimal in short-term trials, and its insulin dosage-reduction activity remains unclear. The Food and Drug Administration has also approved its use as monotherapy and in combination with sulfonylureas for patients with type 2 diabetes. It may have use in the treatment of patients with impaired glucose tolerance, but more clinical experience is needed before definitive conclusions can be made. The role of troglitazone therapy in diabetes mellitus and impaired glucose intolerance will continue to evolve as the results of studies and our clinical experience with this agent become available. OBJETIVO: Introducir un nuevo agente antidiabético llamado troglitazona (CS-045 o Rezulín) y discutir su farmacología, uso terapéutico, farmacocinética, dosificación, reacciónes adversas, interacción con otras drogas, y eficacia clínica. FUENTES DE INFORMACIÓN: Se realizó una busqueda a través del banco de datos de MEDLINE con el propósito de identificar artículos relevantes como repasos, estudios recientes, extractos, y datos obtenidos de la compañía Parke-Davis. SELECCIÓN DE ESTUDIOS: Dada al pequeño número de estudios disponibles en humanos, algunos datos fueron derivados de estudios en animales y extractos de estudios en humanos. Los estudios y extractos seleccionados resumen la actividad clínica de troglitazona en voluntarios saludables, sujetos con intolerancia a glucosa y pacientes con diabetes. Tres de los seis estudios publicados en humanos fueron conducidos de una manera aleatoria, multicentro, y controlados con placebo (pacientes con diabetes tipo 2 y en personas obesas con resistencia a la insulina). MÉTODO DE EXTRACCIÓN DE INFORMACIÓN: Se revisaron todos los estudios clínicos disponibles, incluyendo reportes no publicados. SÍNTESIS: Troglitazona es el primer miembro de una nueva clase de medicamentos llamados tiazolidindiones que fue aprobado para uso clínico. Troglitazona aumenta la sensitividad de insulina en el músculo esquelético y en el tejido hepático y adiposo. Se ha demostrado que este medicamento dismunuye el gasto hepático de glucosa mientras que no produce efecto estimulativo en la secreción de insulina de las células pancreáticas beta. Sus efectos metabólicos producen una disminución en las concentraciones de glucosa en ayuna postprandial y en los niveles de insulina y triglicéridos, mientras que aumenta los niveles de lipoproteína de altadensidad. Evidencia de estudios de corta duración indican que troglitazona causa solamente una mínima disminución en los niveles de hemoglobina glucosilada A1C (HbA1C). Información adicional sugiere que troglitazona disminuye la intolerancia a glucosa en sujetos obesos no-diabéticos y reduce la presión sistólica y diastólica en pacientes hipertensos con diabetes tipo 2. Troglitazona tiene un perfil moderado en sus reacciónes adversas y produce raras occurencias de anormalidades en las pruebas de función hepática. CONCLUSIONES: Troglitazona parece ser un nuevo agente seguro, efficaz y útil en el tratamiento de pacientes con diabetes de tipo 2 que requieren insulina pero su actividad en reducir los niveles de HbA1C reportados en estudios de corta duración es mínimo y su capacidad en reducir las dosis de insulina necesitan ser aclaradas. La Administración de Alimentos y Drogas también aprobó su uso como monoterapia y en combinación con sulfonilureas para pacientes con diabetes tipo 2. Podrá ser usado en pacientes con intolerancia a glucosa pero se necesita más experiencia clínica antes que se pueda hacer conclusiones definitivas. El papel de troglitazona en el tratamiento de la diabetes y la intolerancia a glucosa continuará desarrollando cuando los resultados de estudios y nuestra experiencia clínica con éste agente se hagan disponibles. OBJECTIF: Présenter le troglitazone (CS-045 or Rezulin), un nouvel hypoglycémiant oral et discuter de sa pharmacologie, de sa thérapeutique, de sa pharmacocinétique, de ses recommandations de dosages, des ses effets indésirables, de ses interactions médicamenteuses, et de son efficacité clinique. REVUE DE LITTÉRATURE: Une recherche informatisée de type MEDLINE fut effectuée pour localiser des articles pertinents incluant des articles de révision, des études récentes, et des données provenant de chez la compagnie Parke-Davis. SÉLECTION DES ÉTUDES: À cause du petit nombre d'études humaines publiées disponibles, certaines données sont obtenues à partir d'études animales ou de résumés d'études humaines. Les études et les résumés sélectionnés tracent un sommaire des propriétés cliniques du troglitazone chez le volontaire sain, chez le volontaire avec intolérance au glucose, et chez le volontaire avec un diabète mellitus. Trois des six études humaines publiées à date sont des études contrôlées avec placebo, multicontriques, randomisées avec des patients diabétiques de type II ou des patients obèses avec une résistance à l'insuline. SÉLECTION DE L'INFORMATION: Toutes les études cliniques disponibles compris les études non publiées, furent utilisées. RÉSUMÉ: Le troglitazone est le premier agent d'une nouvelle classe de médicaments, les thiazolidinediones, qui doit être approuvé pour utilisation clinique. Le troglitazone augmente la sensibilité à l'insuline des muscles striés, des tissus adipeux, et hépatiques. Des études ont démontré qu'il diminue la production du glucose hépatique même si il n'a aucun effet de stimulation de sécrétion d'insuline sur les cellules-β du pancréas. Ses effets métaboliques diminuent l'hyperglycémie à jeun et postprandiale, les niveaux d'insuline, et de triglycérides (TG) et augmentent les niveaux de lipoprotéine de densité haute (LDH). Selon certaines évidences, se basant sur des études de courte durée, le troglitazone diminue peu les niveaux d'hémoglobine glycosylée A1C (HbA1C). Des données suggèrent que le troglitazone diminue l'intolérance au glucose chez les obèses non diabétiques et permet une réduction des pressions systolique et diastolique chez des diabétiques de type II hypertendus. Le troglitazone a un profil d'effets indésirables très avantageux. Quelquefois les tests de la fonction hépatique sont altérés. CONCLUSIONS: Le troglitazone semble être un nouvel agent sécuritaire, efficace, et utile pour les diabétiques de type II qui nécessitent un traitement à l'insuline même si ses effets sur l'HbA1C sont minimaux lors des études à courte durée et que son mécanisme d'action pour réduire l'utilisation de l'insuline, reste nébuleux. L'utilisation du troglitazone a aussi été approuvée par l'Administration des Drogues et Alimentaires en monothérapie et en thérapie combinée avec les sulfonylurees chez les diabétiques de type II. Il pourra peut-être être utilisé chez les patients avec intolérance au glucose mais une plus grande expérience clinique est nécessaire pour s'en assurer. Le rôle du troglitazone dans le traitement du diabète de Type II et dans le traitement de l'intolerance au glucose se développe encore à mesure que de nouvelles études sont réalisées et à mesure que notre expérience clinique avec cet agent s'accumule.

Antiangiogenic drugs are used clinically for treatment of different types of cancers and in the case of renal cell carcinoma (RCC) are now standard first-line treatments (Rini, 2009). Nevertheless, these agents mainly serve to stabilize the disease but are not able to eliminate all tumor cells and resistance eventually develops concomitant with progression (Kerber and Folkman, 2002). Using different orthoxenograft mouse models of RCC we confirmed that inhibitors of the VEGF pathway have a therapeutic window of effectiveness but unfortunately adaptation and tumor relapse always occur. Several different mechanisms of resistance to antiangiogenics have been already described, many concerning the activation of compensatory signals that produce re-vascularization and tumor re-growth. (Bergers and Hanahan, 2008). In our study we determined that even if resistance is characterized by the up-regulation of the pro-angiogenic enzyme ECGF1 (previous data from the lab); re-vascularization does not occur, the vascular trimming is maintained by the treatment pointing to an alternative mode of adaptation. Using two different approaches, we demonstrated that PD-ECGF1 is responsible of the acquisition of resistance to anti-anigiogenics. In fact, its enzymatic inhibition as second-line treatment post resistance resulted in the arrest and stabilization of tumor growth. PD-ECGF1 inhibition did not increase the anti-vascular effect of DC101, confirming that resistance was vessel independent, but dramatically affected tumor cell proliferation and apoptosis. Considering the numerous proprieties ascribed to its final metabolite 2-deoxy-D-ribose (Ikeda et al., 2006; Bjinsdorp et al., 2008), we evaluated its role, finding that recombinant 2-deoxy-D-ribose nullified the effect of AEAC on 786O- and Ren28 tumor growth rescuing tumor cell proliferation and apoptosis, without promoting re-vascularization. Overall these findings, confirmed also in an in vitro setting, demonstrate that tumor stroma plays a minor role in this model of anti-angiogenics resistance, and that PD-ECGF1 acts mainly intracellularly supporting tumor cell proliferation and protecting from apoptosis by its enzymatic activity and final metabolite 2-deoxy-D-ribose. Using a genetic approach in which PD-ECGF1 protein expression was silence as a second line of treatment post DC101-resistance, mimicking what done pharmacologically, we confirmed and improved the anti-tumoral response described, without perceiving any doxycycline toxic effect. In fact, PD-ECGF1 genetic knock down resulted in a complete arrest of tumor progression enhancing the merely partial stabilization produce by AEAC treatment in 786O- tumor bearing mice. Unfortunately VEGFR-blockers can’t be used in vitro on cancer cells, and to verify this hypothesis we decided to mimic the final effects of anti-angiogenic treatments, finding that under nutrient deprivation conditions cancer cells significantly up-regulate PD-ECGF1 expression, and metabolizing thymidine acquired considerable growth advantages. Finally, the analysis of plasma and tissue samples of ccRCC patients from the Bellvitge Hospital confirm in a clinical set that PD-ECGF1 is exclusively found in pathologic conditions, where if highly expressed correlates with poor prognosis, suggesting that might represent a good therapeutic predictor factor. Moreover, the analysis of tissues biopsies before and after anti-angiogenic treatment revealed that whilst PD-ECGF1 treatment-induce up-regulation was a common feature, the patients that unfortunately didn’t respond showed the sharp difference, confirming PD-ECGF1 as a possible therapeutic target.
Los fármacos antiangiogénicos se usan clínicamente para el tratamiento de diferentes tipos de cáncer y en el caso del carcinoma de células renales (CCR) representan la primera diana terapéutica (Rini, 2009). Sin embargo, no son capaces de eliminar todas las células tumorales y muchos pacientes desarrollan resistencia al tratamiento y recrecimiento tumoral (Kerber y Folkman, 2002). Mediante el uso de diferentes modelos de ratón hemos confirmado que los inhibidores de la vía VEGF tienen una limitada ventana terapéutica de efectividad, seguida desafortunadamente de adaptación y recaída tumoral que en nuestro estudio esta` caracterizada por la regulación positiva de la enzima PD-ECGF1. Usando dos enfoques diferentes, demostramos que PD-ECGF1 es responsable de la adquisición de resistencia a anti-anigiogénicos. De hecho, su inhibición enzimática como tratamiento de segunda línea después de la resistencia dio como resultado la detención y la estabilización del crecimiento tumoral. La inhibición de PD-ECGF1 no aumentó el efecto antivascular de DC101, pero afectó de manera dramática la proliferación y apoptosis de las células tumorales. Teniendo en cuenta las numerosas propiedades atribuidas a su metabolito final 2-deoxy-D-ribose (Ikeda et al., 2006; Bjinsdorp et al., 2008), evaluamos su papel, encontrando que la 2-deoxy-D-ribose anuló el efecto de la inhibición de PD-ECGF1 rescatando el crecimiento tumoral. Experimentos en vitro demostraron como las células tumorales incrementaban la expresión de PD-ECGF1 en condiciones de falta de nutrientes haciéndonos especular que esta proteína tenga un papel en la adaptación metabolica. Finalmente, el análisis de muestras de plasma y tejido de pacientes con ccRCC del Hospital de Bellvitge confirma en un conjunto clínico que PD-ECGF1 se encuentra exclusivamente en condiciones patológicas, donde se correlaciona con mal pronóstico, sugiriendo que podría representar un buen factor predictor terapéutico.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract. This work considers the pharmacological response in GIST patients treated with imatinib by two different angles: the genetic and somatic point of view. We analyzed polymorphisms influence on treatment outcome, keeping in consideration SNPs in genes involved in drug transport and folate pathway. Naturally, all these intriguing results cannot be considered as the only main mechanism in imatinib response. GIST mainly depends by oncogenic gain of function mutations in tyrosin kinase receptor genes, KIT or PDGFRA, and the mutational status of these two genes or acquisition of secondary mutation is considered the main player in GIST development and progression. To this purpose we analyzed the secondary mutations to better understand how these are involved in imatinib resistance. In our analysis we considered both imatinib and the second line treatment, sunitinib, in a subset of progressive patients. KIT/PDGFRA mutation analysis is an important tool for physicians, as specific mutations may guide therapeutic choices. Currently, the only adaptations in treatment strategy include imatinib starting dose of 800 mg/daily in KIT exon-9-mutated GISTs. In the attempt to individualize treatment, genetic polymorphisms represent a novelty in the definition of biomarkers of imatinib response in addition to the use of tumor genotype. Accumulating data indicate a contributing role of pharmacokinetics in imatinib efficacy, as well as initial response, time to progression and acquired resistance. At the same time it is becoming evident that genetic host factors may contribute to the observed pharmacokinetic inter-patient variability. Genetic polymorphisms in transporters and metabolism may affect the activity or stability of the encoded enzymes. Thus, integrating pharmacogenetic data of imatinib transporters and metabolizing genes, whose interplay has yet to be fully unraveled, has the potential to provide further insight into imatinib response/resistance mechanisms.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract. This work considers the pharmacological response in GIST patients treated with imatinib by two different angles: the genetic and somatic point of view. We analyzed polymorphisms influence on treatment outcome, keeping in consideration SNPs in genes involved in drug transport and folate pathway. Naturally, all these intriguing results cannot be considered as the only main mechanism in imatinib response. GIST mainly depends by oncogenic gain of function mutations in tyrosin kinase receptor genes, KIT or PDGFRA, and the mutational status of these two genes or acquisition of secondary mutation is considered the main player in GIST development and progression. To this purpose we analyzed the secondary mutations to better understand how these are involved in imatinib resistance. In our analysis we considered both imatinib and the second line treatment, sunitinib, in a subset of progressive patients. KIT/PDGFRA mutation analysis is an important tool for physicians, as specific mutations may guide therapeutic choices. Currently, the only adaptations in treatment strategy include imatinib starting dose of 800 mg/daily in KIT exon-9-mutated GISTs. In the attempt to individualize treatment, genetic polymorphisms represent a novelty in the definition of biomarkers of imatinib response in addition to the use of tumor genotype. Accumulating data indicate a contributing role of pharmacokinetics in imatinib efficacy, as well as initial response, time to progression and acquired resistance. At the same time it is becoming evident that genetic host factors may contribute to the observed pharmacokinetic inter-patient variability. Genetic polymorphisms in transporters and metabolism may affect the activity or stability of the encoded enzymes. Thus, integrating pharmacogenetic data of imatinib transporters and metabolizing genes, whose interplay has yet to be fully unraveled, has the potential to provide further insight into imatinib response/resistance mechanisms.

Orientador: Mario Jose Abdalla Saad
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
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Resumo: As óxido nítrico sintases (NOS) são divididas em dois grandes grupos de enzimas, NOS induzível (iNOS) e NOS constitutivas (cNOS). Embora o óxido nítrico (NO) seja um importante mediador de defesa do organismo, a produção excessiva de NO está envolvida na patogênese de muitas doenças inflamatórias e metabólicas. Alguns estudos demonstram que o óxido nítrico exógeno e o NO produzido pela iNOS pode induzir resistência à insulina em músculo e desempenha um papel importante na hiperglicemia de jejum. Este estudo teve como objetivo sintetizar e investigar o efeito de um potente e seletivo inibidor de atividade da iNOS, o Iodato de S-Metilisotiouréia (I-SMT) 5 mg/kg por dia, na hiperglicemia de jejum e na resistência à insulina em um modelo de obesidade induzida por dieta hiperlipídica. Foram observados os parâmetros metabólicos e de sinalização celular da Proteína quinase B/Akt (Akt) e os resultados fornecem evidências de que o grupo tratado com I-SMT foi protegido contra o desenvolvimento de resistência à insulina, e intolerância à glicose induzida por dieta hiperlipídica. Portanto, propomos que potentes inibidores farmacológicos, com seletividade significativa pela iNOS podem representar uma nova abordagem terapêutica para o tratamento da resistência à insulina e suas complicações como o diabetes tipo 2.
Abstract: Nitric oxide synthase (NOS) has been divided into two major sub-enzymes, inducible NOS (iNOS) and constitutive NOS (cNOS). Although nitric oxide (NO) is an important defense mediator, the excessive production of NO has been involved in the pathology of many inflammatory and metabolic diseases. Some studies demonstrate that exogenous nitric oxide (NO) and the NO produced by iNOS can induce insulin resistance in muscle and plays an important role in fasting hyperglycemia. This study investigates the effect of a potent and selective iNOS activity inhibitor, the S-Methylisothiourea Iodide (SMT-I) 5 mg/kg per day, in fasting hyperglycemia and insulin resistance in diet-induced obesity model. We observed the metabolic parameters and Akt signalization and these findings provide evidence that the SMT-I treated group are protected against the development of insulin resistance, glucose intolerance and diet-induced obesity. Therefore, we propose that highly selective inhibitors of iNOS activity may represent a novel therapeutic approach for the therapy of insulin resistance and its complications as type 2 diabetes.
Mestrado
Biologia Estrutural, Celular, Molecular e do Desenvolvimento
Mestre em Fisiopatologia Médica

An emerging anticancer strategy is to identify molecular targets that when inhibited pharmacologically, result in pleiotropic downstream effects on pathways relevant to the malignant phenotype, with particular reference to the development of resistance. In recent years, the molecular chaperone Hsp90 has emerged as leading example of such a target-specific therapy. Heat-shock proteins are found at increased levels in many solid tumors and haematological malignancies. Their expression may account for the ability of malignant cells to maintain protein homeostasis even in the hostile hypoxic microenvironment of the tumor. Particularly, Hsp90 has emerged as a target for cancer therapy due to its critical roles in retaining the conformation and the function of its client proteins, many of which are associated with cancer pathology. There are 12 HSP90 inhibitors in clinical trials; all have potencies on the order of 7-35 nM in a cell-based assay and half-lives of 1-3 h in the plasma of rodents. These inhibitors may distribute preferentially to the tumors and may have longer half-lives in the tumors than in the plasma, as in the case of 17-AAG and its active metabolite. However, side effects and poor formulability of 17-AAG restricted its potential of clinical application and motivated many groups to synthesize new compounds. The aim of this project is to identify new Hsp90 inhibitors which could overcome the limitations of available inhibitors and exhibit therapeutic advantages in terms of specificity, therapeutic index and antitumor efficacy. Several compounds have been tested during these years, especially a series of mold metabolites of Ascomycetes, structurally belonging to the class of azaphilones, were found to inhibit the heat shock protein Hsp90. In particular, bulgarialactone B was tested for its binding to Hsp90 using surface plasmon resonance and limited proteolysis assays and for its effects on Hsp90 client proteins expression in a series of human tumor cell lines. This compound showed high affinity for Hsp90, interacting with the 90–280 region of the N-terminal domain and down-regulated the Hsp90 clientproteins Raf-1, survivin, Cdk4, Akt, and EGFR. Bulgarialactone B and other natural azaphilones showed antiproliferative activity in a panel of human tumor cell lines; their conversion into semisyntheticderivatives by reaction with primary amines increased the antiproliferative activity. Preliminary results indicated in vivo activity of bulgarialactone B against an ascitic ovarian carcinoma xenograft, thus supporting the therapeutic potential of this novel series of Hsp90 inhibitors. Moreover, to identify favourable interactions between Hsp90 inhibitors and target-specific agents, combinations between curcumin and two well-known HDAC inhibitors (vorinostat and panobinostat), have been tested. Curcumin, a natural polyphenol, has been described to exhibit effects on signaling pathways, leading to induction of apoptosis. In this study, we observed that curcumin inhibited Hsp90 activity causing depletion of client proteins implicated in survival pathways. Based on this observation, the study was designed to investigate the cellular effects of curcumin combination with the pan- HDAC inhibitors, vorinostat and panobinostat, which induce hyperacetylation of Hsp90, resulting in inhibition of its chaperone function. The results showed that, at subtoxic concentrations, curcumin markedly sensitized tumor cells to vorinostat- and panobinostat-induced growth inhibition and apoptosis. The sensitization was associated with persistent depletion of Hsp90 client proteins (EGFR, Raf-1, Akt, and survivin). In conclusion, our findings document a novel mechanism of action of curcumin and support the therapeutic potential of curcumin/HDAC inhibitors combination, because the synergistic interaction was observed at pharmacologically achievable concentrations, which were ineffective when each drug was used alone. Another new therapeutic target is GGT (gamma-glutamyl transferase), the interest in this enzyme is related to recent evidence supporting that it is implicated in tumor progression and in drug resistance to stress-inducing agents (i.e. platinum compounds). The extracellular -glutamyltransferase-mediated metabolism of glutathione has been implicated in prooxidant events which may have impact on cellular functions including drug resistance. Therefore the objective of this approach was to investigate the role of GGT in response to various stress-inducing agents. The study was performed in two GGT-transfected melanoma clones to explore the hypothesis that GGT expression in tumour cells is implicated in modulation of cell behaviour under stress conditions. Our results show that GGT-overexpression in melanoma cells was associated with resistance to oxidative stress produced by prooxidant agents such as hydrogen peroxide and ascorbic acid. In GGT-overexpressing cells, ability to tolerate oxidative stress was evidenced by the presence of a moderate level of ROS and lack of DNA damage response following treatment with H2O2. Cellular response to oxidative stress induced by ascorbic acid was detectable only in the clone with low GGT activity which also exhibited an increased susceptibility to apoptosis. The increased resistance of the GGT-overexpressing clone was not related to intracellular GSH content but rather to the increased expression of catalase and to a reduced efficiency of iron-mediated formation of toxic free radicals. Taken together, these findings are consistent with a contribution of GGT in the mechanisms of drug resistance, because induction of oxidative stress is a relevant event in the apoptotic response to cytotoxic agents. Again, in an attempt to develop novel strategies for overcoming the mechanisms of cellular protection against oxidative stress, we have explored the efficacy of the combination of two prooxidant agents in the two human melanoma cell clones differently expressing GGT. The γ-glutamyltransferase-overexpressing clone exhibited a low susceptibility to arsenic trioxide-induced apoptosis, associated with low reactive oxygen species induction and increased catalase activity. The combination of arsenic trioxide with subtoxic concentrations of ascorbic acid resulted in a sensitization to apoptotic cell death. The expression of protective mechanisms, in particular catalase activity, accounted for the behavior of the resistant clone. The sensitization achieved by the combination was associated with a cellular response involving the ASK1/p38 axis, which is implicated in the regulation of catalase expression and the activation of apoptotic signals. In conclusion, the results of our study provide evidence that a rational combination of prooxidant agents may be effective in overcoming cellular tolerance to oxidative stress. Moreover, as a number of recent observations have suggested a potential role for membrane-bound gammaglutamyltransferase (GGT) in tumor progression through redox interactions leading to production of reactive oxygen species, we performed a study to evaluate whether such pro-oxidant activity of GGT can promote oxidative DNA damage, thus contributing to cancer genomic instability. Human GGT-transfected melanoma cells were studied, and DNA damage was measured by using the alkaline comet assay. Our results indicate that higher levels of GGT activity are associated with higher levels of background DNA damage and oxidized bases. This association cannot be explained by differences in cell cycle distribution or apoptotic rates. GGT-over-expressing cells also presented with a markedly higher glucose uptake, a phenomenon potentially leading to higher metabolic rate and oxidative DNA damage. Anyway, when GGT-over-expressing cells were incubated in the presence of GGT substrates and a source of catalytic iron, increased levels of DNA damage and oxidized bases were observed, an effect completely prevented in the presence of GGT inhibitors or various antioxidants. The findings reported indicate that GGT activity is able to promote iron-dependent DNA oxidative damage, thus potentially representing an important mechanism in initiation/progression of neoplastic transformation.

Cisplatin is one of the most potent anticancer agents used in the treatment of various solid tumors. Unfortunately, the onset of resistance still limits its use in therapy and severely compromises the treatment effectiveness. Although several studies have been performed, the molecular mechanisms involved in cisplatin resistance are not completely understood. Recently, a metabolic rewiring has been shown to play a prominent role in the response of cancer cells to first-line chemotherapeutic agents, indicating the metabolic pathways as powerful mediators of resistance to cancer treatments. Previous studies of our laboratory had already demonstrated a metabolic switch of cisplatin-resistant cells toward glycolysis and to an altered mitochondrial functionality and morphology. So, in order to better characterize the metabolic fingerprint of cisplatin-resistant cells, in this work the lipid metabolic pathway and the glutamine metabolism have been investigated in models of gynecological cancer cells and Triple-negative breast cancer cells, sensitive and resistant to cisplatin. Aerobic glycolysis, mitochondrial reprogramming, and deregulation of lipid metabolism are not independent pathways but rather they cooperate to sustain cells proliferation and to allow cells survival in a challenging environment induced also by chemotherapeutic drugs. The characterization of the metabolic fingerprint of cells and the interconnection between the different pathways is essential to identify specific targets in cisplatin-resistant cancer cells useful to design pharmacological strategies to bypass resistance. Results indicate a deregulation of the lipid homeostasis in resistant cells which induces a significant lipid accumulation; moreover, preliminary results indicate that resistant cells rely more on glutamine for their survival. From this study and previous observations of our laboratory, different possible metabolic targets specific of cisplatin-resistant cells have been identified, and different pharmacological approaches able to target the identified alterations in lipid metabolism and mitochondria remodeling have been tested. This work fits in the research panorama aimed at providing new insights into the differential metabolic dependencies of cisplatin-resistant tumors. Results may provide novel therapeutic targets exploitable to overcome cisplatin resistance and to enhance the efficacy of the current chemotherapy.
Il cisplatino è uno dei più potenti agenti antitumorali utilizzati nel trattamento di vari tumori solidi. L’insorgenza di fenomeni di resistenza al farmaco è uno dei fattori che ne limita l’utilizzo in terapia e compromette gravemente l’efficacia del trattamento. Nonostante numerosi studi siano stati condotti negli ultimi anni, i meccanismi molecolari coinvolti nella resistenza al cisplatino non sono ancora stati completamente elucidati. Recentemente è stato dimostrato che un ruolo chiave nella risposta cellulare ai farmaci antitumorali è svolto da una riprogrammazione del metabolismo cellulare, indicando le vie metaboliche come potenti mediatori della resistenza ai trattamenti chemioterapici. Studi precedentemente condotti nel nostro laboratorio su cellule di carcinoma ovarico avevano già dimostrato uno shift metabolico verso la glicolisi e alterazioni a livello di funzionalità/morfologia mitocondriale nei cloni resistenti al cisplatino (C13). L’obiettivo di questo lavoro quindi è stato quello di studiare i pathways del metabolismo lipidico e della glutammina allo scopo di ottenere una caratterizzazione più completa del profilo metabolico delle cellule resistenti. Per questo studio sono stati utilizzati diversi modelli cellulari di tumore ginecologico e diverse linee cellulari di tumore mammario triplo negativo, sensibili e resistenti al cisplatino. È importante sottolineare come glicolisi aerobica, riprogrammazione mitocondriale e del metabolismo lipidico non sono vie indipendenti, ma cooperano per sostenere l’omeostasi cellulare e consentire la sopravvivenza delle cellule in ambienti ostili, indotti anche da farmaci chemioterapici. Caratterizzare il profilo metabolico delle cellule e le interconnessioni tra i diversi pathways è essenziale per l’identificazione di target molecolari tumore-resistente specifici sfruttabili per approcci farmacologici innovativi. I risultati ottenuti indicano come le cellule resistenti al cisplatino presentino una alterazione dell’omeostasi lipidica che induce un significativo accumulo intracellulare di lipidi; inoltre gli studi preliminari riguardanti il ruolo della glutammina indicano come la sopravvivenza delle cellule resistenti sia particolarmente dipendente dal metabolismo di questo aminoacido. Da questo studio, e da precedenti osservazioni del nostro laboratorio, sono stati identificati diversi possibili target metabolici specifici delle cellule cisplatino-resistenti, sia a livello di vie metaboliche lipidiche sia a livello mitocondriale. Questo lavoro si inserisce nel panorama di ricerca volto ad approfondire le specifiche dipendenze metaboliche di tumori cisplatino-resistenti. I risultati ottenuti potranno fornire nuovi target terapeutici sfruttabili al fine di superare la resistenza al cisplatino e migliorare l’efficacia dell’attuale trattamento chemioterapico.

Background. Abiraterone acetate is a potent inhibitor of cytochrome P450 17 α-hydrolase (CYP17A1) that causes a reduction in the synthesis of testosterone in the adrenal glands, testes and tumor microenvironment. Blocking androgen production, abiraterone has been shown to prolong progression-free survival (PFS) and overall survival (OS) in patients with metastatic castration-resistant prostate cancer (CRPC) previously submitted to chemotherapy. The aim of our study was to verify the role of single nucleotide polymorphisms (SNPs) in predicting clinical outcome in CRPC patients treated with abiraterone after chemotherapy. Methods. We analyzed 48 CRPC consecutive patients treated with abiraterone after at least one chemotherapeutic regimen with docetaxel. DNA was extracted from peripheral blood and genotyped for four polymorphisms in the CYP17A1 gene (rs743572, rs10883783, rs17115100, rs284849). PFS and OS survival curves were used to identify statistical associations between haplotypes and clinical outcome. Results. Forty-eight Caucasian patients with metastatic CRPC treated with abiraterone were genotyped for polymorphisms in the CYP17A1 gene. All samples were evaluable for both sequencing and TaqMan Genotyping assay. The CRPC patients treated with abiraterone had a median PFS and OS of 7.6 months (95% CI: 4.3-10.5) and 17.6 months (95% CI: 10.5-19.0), respectively Statistical analyses highlighted a difference approaching statistical significance (log-rank test p = 0.0534) between rs10883783 and PFS. Other polymorphisms were not associated with a benefit from treatment with abiraterone. Conclusions. In our case series of 48 treated patients, rs10883783 only was identified as a possible predictive marker, results showing a trend toward statistical significance. Further analysis of this polymorphism is needed in larger series of patients to confirm our findings.

Background. Abiraterone acetate is a potent inhibitor of cytochrome P450 17 α-hydrolase (CYP17A1) that causes a reduction in the synthesis of testosterone in the adrenal glands, testes and tumor microenvironment. Blocking androgen production, abiraterone has been shown to prolong progression-free survival (PFS) and overall survival (OS) in patients with metastatic castration-resistant prostate cancer (CRPC) previously submitted to chemotherapy. The aim of our study was to verify the role of single nucleotide polymorphisms (SNPs) in predicting clinical outcome in CRPC patients treated with abiraterone after chemotherapy. Methods. We analyzed 48 CRPC consecutive patients treated with abiraterone after at least one chemotherapeutic regimen with docetaxel. DNA was extracted from peripheral blood and genotyped for four polymorphisms in the CYP17A1 gene (rs743572, rs10883783, rs17115100, rs284849). PFS and OS survival curves were used to identify statistical associations between haplotypes and clinical outcome. Results. Forty-eight Caucasian patients with metastatic CRPC treated with abiraterone were genotyped for polymorphisms in the CYP17A1 gene. All samples were evaluable for both sequencing and TaqMan Genotyping assay. The CRPC patients treated with abiraterone had a median PFS and OS of 7.6 months (95% CI: 4.3-10.5) and 17.6 months (95% CI: 10.5-19.0), respectively Statistical analyses highlighted a difference approaching statistical significance (log-rank test p = 0.0534) between rs10883783 and PFS. Other polymorphisms were not associated with a benefit from treatment with abiraterone. Conclusions. In our case series of 48 treated patients, rs10883783 only was identified as a possible predictive marker, results showing a trend toward statistical significance. Further analysis of this polymorphism is needed in larger series of patients to confirm our findings.

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A tuberculose à uma doenÃa infectocontagiosa, que persiste ao longo da histÃria mundial como um sÃrio problema de saÃde pÃblica. à causada pelo Complexo Mycobacterium tuberculosis. O MinistÃrio da SaÃde considera a tuberculose como uma doenÃa prioritÃria no Brasil, pois o mesmo ocupa o 17 lugar entre os 22 paÃses em desenvolvimento, responsÃveis por 80% dos casos mundiais dessa enfermidade. TÃm-se verificado um aumento no nÃmero de casos de resistÃncia bacteriana Ãs drogas antituberculose. Este estudo teve carÃter descritivo e foi retrospectivo dos anos de 2005 a 2007 e prospectivo de 2008 a 2009, tendo por objetivo avaliar o diagnÃstico da tuberculose e o perfil de resistÃncia Ãs drogas antituberculose em 563 exames de pacientes atendidos nos ServiÃos de SaÃde do Estado no LACEN-PI, atravÃs da cultura e teste de sensibilidade de variadas espÃcimes biolÃgicas. De 563 casos encontrados avaliados, 123 apresentaram cultura positiva, dos quais cerca de 91,8 % apresentaram a forma pulmonar da doenÃa, sendo 65 % da populaÃÃo avaliada do sexo masculino. A mÃdia da idade em anos foi de 43,97Â16,81 (1-89). Em todos os anos, os casos tratados superaram em 92,6% os casos novos. Identificou-se qualquer resistÃncia em 68 casos (55,3%). A taxa de resistÃncia primÃria e adquirida foi, 3% e 97%, respectivamente. Foi encontrado 39 casos (31,7%) de multirresistÃncia, 15 casos (12,1%) de monorresistÃncia, 14 casos (11,3%) de polirresistÃncia. Conclui-se que os nÃveis de resistÃncia encontrados sÃo elevados. Dessa forma, faz-se necessÃrios o monitoramento dos nÃveis de resistÃncia, o controle adequado dos casos de tuberculose no PiauÃ, com a ampliaÃÃo dos exames de cultura e teste de sensibilidade para o diagnÃstico precoce. TambÃm deve ser encorajado o desenvolvimento de mais pesquisas para padronizaÃÃo de novos testes de diagnÃsticos que sejam prÃtico, rÃpido, de fÃcil execuÃÃo, baixo custo que reÃna alta especificidade e sensibilidade para a doenÃa
Tuberculosis is an infectious and contagious disease which persists throughout world history as a serious public health problem. It is caused by the complex Mycobacterium tuberculosis. The Ministry of Health considers tuberculosis a priority disease in Brazil, because the country occupies the 17th place among 22 developing countries, all together responsible for 80% of the worldwide cases of this disease. There has been an increase in the number of bacterial resistance cases to antituberculosis drugs. This study was descriptive and retrospective study of the years 2005 to 2007 and prospective from 2008 to 2009, aiming to assess the diagnosis of tuberculosis and the profile of antituberculosis drug resistance tests in 563 patients treated in the Health Services of the State in LACEN -PI, through culture and sensitivity testing of various biological specimens. From 563 cases, 123 were positive to culture, of which about 91.8% had the pulmonary form of the disease, being 65% of the population in focus consisting of male sex individuals. The mean age in years was 43.97 Â 16.81 (1 - 89). In all years, the cases treated exceeded in 92.6% the new cases. No resistance was identified in 68 cases (55.3%). The rate of primary and acquired resistance was 3% and 97% respectively. It was found 39 cases (31.7%) of multi-drug resistance, 15 cases (12.1%) of single drug resistance, and 14 cases (11.3%) of full range drug resistance. The conclusion is that levels of resistance found are high. Thus, it is necessary to monitor the resistance levels, in addition to adequate control of tuberculosis cases in PiauÃ, by expanding the culture testing and sensitivity testing for early diagnosis. It should also be encouraged to develop more research to standardize new diagnostic tests that are practical, fast, easily run, low cost and possessing high specificity and sensitivity for the disease

The onset of resistance to cisplatin still limits its use in the chemotherapy of ovarian cancer and, despite several mechanisms of resistance have been discovered, they are not exhaustive. The aim of this study was to identify which other pathways are exploited by cancer cells to escape cisplatin cytotoxicity, to possibly prevent or overcome the phenomenon with new pharmacological approaches. The increase of anaerobic glycolysis, even in the presence of oxygen (Warburg effect), is the first observation indicating the alteration of energetic metabolism used by tumor cells as a strategy to adapt and grow independently from the availability of the substrate. This evidence suggested us to investigate the hypothesis that a similar metabolic strategy might be of relevance in resistance to cisplatin. Recently it has been shown that only approximately 1% of intracellular platinum is bound to nuclear DNA, while the great majority of the intracellular drug is available to interact with other nucleophilic sites including but not limited to phospholipids, cytosolic, cytoskeletal and membrane proteins, RNA and mitochondrial DNA. mtDNA, unlike nDNA, does not possess efficient repair systems and is therefore more susceptible to the onset of mutations often associated to cancer development, loss of tumor suppressor, activation of oncogenes and mitochondrial dysfunctions often related with an increase of glycolytic activity. Therefore, the aim of this study was to investigate the energetic metabolism and the mitochondrial function of cisplatin-resistant (C13) and sensitive (2008) ovarian cancer cells with different experimental approaches. Results revealed that resistant cells present a significant reduced respiratory chain activity correlated to a lower mitochondrial mass, altered mitochondrial morphology as well as a metabolomic profile typical of a lipogenic phenotype. To investigate the role of mtDNA and nDNA in the mitochondrial and metabolic remodeling of cisplatin-resistant line, cancer cells (2008-C13) were used to generate transmitochondrial hybrids (H2008-HC13). Mitochondrial DNA of parental and hybrid cells was sequenced, showing similar, almost non pathological, polymorphisms. Interestingly, investigating the energetic metabolism and the mitochondrial structure of hybrids, no differences were observed between H2008 and HC13. These data demonstrated that the metabolic reprogramming of C13 cells was not dependent from mtDNA, but was controlled by nuclear factors. Having regard to these data, the activity of some nuclear transcription factors (HIF-1α, and c-Myc) involved in the metabolic reprogramming of tumor cells, has been evaluated and it has been highlighted a different expression of some of their target genes involved in the glycolytic flux. Finally, the metabolic profile of 2008-C13 cells has been outlined by LC-MS which evidenced some interesting differences in aminoacids, phospholipids and antioxidants content.
L’utilizzo del cisplatino nel trattamento del cancro all’ovaio è tutt’oggi limitato dall’insorgenza di chemioresistenza. Nonostante siano stati evidenziati numerosi meccanismi implicati nella resistenza al cisplatino, questo fenomeno non è ancora stato del tutto chiarito. Lo scopo di questo studio è stato quindi quello di identificare quali altre strategie vengano sfruttate dalle cellule tumorali per sfuggire alla citotossicità indotta dal cisplatino in modo da prevenire o superare la resistenza attraverso l’utilizzo di nuovi approcci farmacologici. L'aumento della glicolisi anaerobica, anche in presenza di alte concentrazioni di ossigeno (effetto Warburg), è la più nota e meglio conosciuta alterazione del metabolismo energetico utilizzato dalle cellule tumorali come strategia per adattarsi e crescere in modo indipendente dalla disponibilità del substrato. Queste evidenze scientifiche ci hanno suggerito di indagare l'ipotesi che una simile strategia possa essere rilevante nell’insorgenza della resistenza al cisplatino. Recentemente è stato dimostrato che solo ~1% del platino intracellulare si lega al DNA nucleare, mentre la gran parte del farmaco interagisce con altri siti nucleofili tra cui fosfolipidi, proteine di membrana, RNA e DNA mitocondriale. Il mtDNA, a differenza del nDNA, non possiede sistemi di riparazione efficaci ed è quindi più suscettibile all’insorgenza di mutazioni e trasformazioni oncogeniche spesso associate allo sviluppo del cancro, perdita di oncosoppressori, attivazione di oncogeni e ad alterazioni della funzionalità mitocondriale correlata ad aumento dell'attività glicolitica. Pertanto, l'obiettivo di questo studio è stato quello di studiare il metabolismo energetico e la funzione mitocondriale delle cellule di cancro ovarico sensibili (2008) e resistenti (C13) al cisplatino utilizzando diversi approcci sperimentali. I risultati hanno evidenziato che le cellule resistenti presentano una significativa riduzione dell'attività della catena respiratoria correlata ad una minore massa mitocondriale, alterata morfologia mitocondriale nonché un profilo metabolico tipico di un fenotipo lipogenico. Per studiare il ruolo del mtDNA e del nDNA nel rimodellamento metabolico e mitocondriale osservato nella linea resistente al cisplatino, le cellule tumorali (2008-C13) sono state utilizzate per generare ibridi transmitocondriali (H2008-HC13). Il DNA mitocondriale delle cellule parentali e degli ibridi citoplasmatici è stato quindi sequenziato, mostrando polimorfismi simili, ma non patologici. È interessante notare che, le differenze metaboliche e mitocondriali evidenziate nelle linee tumorali, non vengono mantenute nei rispettivi cibridi dimostrando che la riprogrammazione metabolica delle cellule C13 non è influenzata dal mtDNA, ma è controllata da fattori nucleari. Alla luce di tali dati, è stata quindi valutata l’attività di alcuni noti fattori di trascrizione (HIF-1α e c-Myc) coinvolti nella riprogrammazione metabolica delle cellule tumorali ed è stata evidenziata una diversa espressione di alcuni dei loro geni target implicati nel flusso glicolitico. Infine il profilo metabolico delle linee 2008-C13 è stato delineato mediante LC-MS da cui sono emerse interessanti differenze nel contenuto lipidico, amminoacidico e di alcuni noti agenti antiossidanti.