Showing papers by "Ana Maria Oliveira Battastini published in 2009"

Sustained release from lipid-core nanocapsules by varying the core viscosity and the particle surface area.

Abstract: Based on the structure of polymeric nanocapsules containing a lipid-dispersed core composed of caprylic/capric trygliceride (CCT) and sorbitan monostearate (SM), we hypothesized that varying the core component concentrations the drug release kinetic could be modulated. Our objective was also to determine the parameters which were responsible for controlling the drug release kinetics. The nanocapsules were prepared by interfacial deposition of poly(epsilon-caprolactone). Interfacial hydrolysis of indomethacin ester (IndOEt) was used to simulate a sink condition of release. Mathematical modeling showed that the IndOEt half-lives increased (198 to 378 and 263 to 508 min) with the increase in the core lipid concentrations, and that the release mechanism was the anomalous transport. By increasing the SM concentration, the diameters were constant (around 250 nm) and the surface areas increased (from 1.06 x 10(4) to 1.51 x 10(4) cm2 x ml(-1)), while by increasing the CCT concentration, the diameters increased (215 to 391 nm) and the surface areas reduced (1.46 x 10(4) to 1.06 x 10(4) cm2 x ml(-1)). The presence of SM increased the viscosity of CCT and the IndOEt apparent permeability decreased from 4.26 x 10(-7) to 2.54 x 10(-7) cm x s(-1), while for CCT series, the apparent permeability was constant around 3.0 x 10(-7) cm x s(-1). A mathematical correlation was established and the IndOEt apparent permeability can be estimated by the SM concentration. In conclusion, varying the CCT and SM concentrations the IndOEt release was controlled by the nanocapsule surface area and by the viscosity of the core, respectively.

Effects of indomethacin-loaded nanocapsules in experimental models of inflammation in rats

Abstract: Background and purpose: The effects of systemic treatment with indomethacin-loaded nanocapsules (IndOH-NC) were compared with those of free indomethacin (IndOH) in rat models of acute and chronic oedema. Experimental approach: The following models of inflammation were employed: carrageenan-induced acute oedema (measured between 30 min and 4 h), sub-chronic oedema induced by complete Freund's adjuvant (CFA) (determined between 2 h and 72 h), and CFA-induced arthritis (oedema measured between 14 and 21 days). Key results: IndOH or IndOH-NC produced equal inhibition of carrageenan-elicited oedema. However, IndOH-NC was more effective in both the sub-chronic (33 ± 4% inhibition) and the arthritis (35 ± 2% inhibition) model of oedema evoked by CFA, when compared with IndOH (21 ± 2% and 14 ± 3% inhibition respectively) (P < 0.01). In the CFA arthritis model, treatment with IndOH-NC markedly inhibited the serum levels of the pro-inflammatory cytokines tumour necrosis factor α and IL-6 (by 83 ± 8% and 84 ± 11% respectively), while the levels of the anti-inflammatory cytokine IL-10 were significantly increased (196 ± 55%). The indices of gastrointestinal damage in IndOH-NC-treated animals were significantly less that those after IndOH treatment (58 ± 16%, 72 ± 6% and 69 ± 2%, for duodenum, jejunum and ileum respectively). Conclusions and implications: IndOH-NC produced an increased anti-inflammatory efficacy in long-term models of inflammation, allied to an improved gastrointestinal safety. This formulation might represent a promising alternative for treating chronic inflammatory diseases, with reduced undesirable effects. This article is part of a themed issue on Mediators and Receptors in the Resolution of Inflammation. To view this issue visit http://www3.interscience.wiley.com/journal/121548564/issueyear?year=2009

Selective NTPDase2 expression modulates in vivo rat glioma growth

Abstract: The ectonucleoside triphosphate diphosphohydrolases (E-NTPDases) are a family of ectoenzymes that hydrolyze extracellular nucleotides, thereby modulating purinergic signaling. Gliomas have low expression of all E-NTPDases, particularly NTPDase2, when compared to astrocytes in culture. Nucleotides induce glioma proliferation and ATP, although potentially neurotoxic, does not evoke cytotoxic action on the majority of glioma cultures. We have previously shown that the co-injection of apyrase with gliomas decreases glioma progression. Here, we tested whether selective re-establishment of NTPDase2 expression would affect glioma growth. NTPDase2 overexpression in C6 glioma cells had no effect on in vitro proliferation but dramatically increased tumor growth and malignant characteristics in vivo. Additionally, a sizable platelet sequestration in the tumor area and an increase in CD31 or platelet/endothelial cell adhesion molecule-1 (PECAM-1), vascular endothelial growth factor and OX-42 immunostaining were observed in C6-Enhanced Yellow Fluorescent Protein (EYFP)/NTPDase2-derived gliomas when compared to controls. Treatment with clopidogrel, a P2Y(12) antagonist with anti-platelet properties, decreased these parameters to control levels. These data suggest that the ADP derived from NTPDase2 activity stimulates platelet migration to the tumor area and that NTPDase2, by regulating angiogenesis and inflammation, seems to play an important role in tumor progression. In conclusion, our results point to the involvement of purinergic signaling in glioma progression.

Anti-proliferative effect of the gastrin-release peptide receptor antagonist RC-3095 plus temozolomide in experimental glioblastoma models

Abstract: Malignant gliomas have a dismal prognosis despite multi-modality treatments like neurosurgical resection, radiation therapy and chemotherapy. Evidence has indicated that gastrin-releasing peptide (GRP) and its receptor (GRPR) play a role in the development of a variety of cancers including gliomas. In the present study, we investigated the effects of RC-3095, a selective GRPR antagonist, alone or in combination with temozolomide (TMZ), a DNA alkylating agent, in in vitro and in vivo experimental rat C6 glioma models. Cellular proliferation was significantly reduced by all treatments with the combined administration of TMZ and RC-3095 being the most effective treatment. In in vivo experiments, the control group displayed the largest tumors (52 ± 15.5 mm3), whereas RC-3095 reduced the tumor size, with the most significant effect at the dose of 0.3 mg/kg (21 ± 9.7 mm3). The combined therapy produced further reduction in tumor size (10 ± 7.5 mm3). Our results show that the combination of RC-3095 with TMZ produced an important reduction in in vitro and in vivo glioma growth therefore making RC-3095 a candidate drug to potentiate the effects of the DNA alkylating agent TMZ in the treatment of glioma.

Brazilian marine sponge Polymastia janeirensis induces apoptotic cell death in human U138MG glioma cell line, but not in a normal cell culture

Abstract: Marine sponges have been prominently featured in the area of cancer research. Here, we examined the anti-proliferative effects of crude extracts (aqueous and organic) of the Brazilian marine sponge Polymastia janeirensis in the U138MG human glioma cell line. Moreover, we examined the effects of extracts on selective cytotoxicity in the glioma cells in comparison with a normal cell culture. Exposure of glioma cells to treatments (24 h) resulted in cell number decrease at all doses tested, with both aqueous and organic extracts (IC50 <20 and <30 μg/ml, respectively). Parallel to this result, sponge extracts reduced glioma cell viability (IC50 <15 μg/ml for both extracts). However, higher doses (50 and 100 μg/ml) induced a stronger cytotoxic effect when compared to the lower dose tested (10 μg/ml), inhibiting more than 80% of cellular growth and viability. Propidium iodide uptake and flow cytometry analysis further showed that sponge extracts caused necrosis in the glioma cell line at higher doses, while a high percentage of apoptotic glioma cells were observed at 10 μg/ml. Moreover, apoptosis was prevented by the pan-caspase inhibitor Z-VAD, suggesting that marine sponge extracts, at lower doses, induce caspase-dependent apoptosis in U138MG glioma cells. Surprisingly the extracts herein tested were more effective than temozolomide, a potent inductor of apoptosis used for the treatment of malignant gliomas. Furthermore, our results suggested a selectivity cytotoxic effect on glioma cell line in comparison with a normal cell culture, since the effect on viability found in glioma cells was not observed in astrocyte cultures with the lower dose (10 μg/ml). Thus, this marine sponge may be considered a good candidate for development of new cancer medicines with antitumor activity against gliomas.

A comparative study of ectonucleotidase and P2 receptor mRNA profiles in C6 cell line cultures and C6 ex vivo glioma model.

Abstract: Glioblastoma multiforme is the most common type of primary brain tumour and has the worst clinical outcome. Nucleotides represent an important class of extracellular molecules involved in cell proliferation, differentiation and apoptosis. Alterations in purinergic signalling have been implicated in pathological processes, such as cancer, and glioma cell lines are widely employed as a model to study the biology of brain tumours. Increasing evidence, however, suggests that glioma cell lines may not present all the phenotypic and genetic characteristics of the primary tumours. We have compared the biological characteristics of C6 rat glioma cells in culture and the same cells after their implantation in the rat brain and growth in culture (denominated as the C6 ex vivo culture model). Parameters evaluated included cell morphology, differentiation, angiogenic markers, purinergic receptors and ecto-nucleotidase mRNA profile/enzymatic activity. Analysis of the C6 glioma cell line and C6 ex vivo glioma cultures revealed distinct cell morphologies, although cell differentiation and angiogenic marker expressions were similar. Both glioma models co-expressed multiple P2X and P2Y receptor subtypes with some differences. In addition, the C6 glioma cell line and C6 ex vivo glioma cultures exhibited similar extracellular ATP metabolism and cell proliferation behaviour when exposed to cytotoxic ATP concentrations. Thus, the disruption of purinergic signalling is a feature shown not only by glioma cell lineages, but also by primary glioma cultures. Our results therefore suggest the participation of the purinergic system in glioma malignancy.

Extracts of marine sponge Polymastia janeirensis induce oxidative cell death through a caspase-9 apoptotic pathway in human U138MG glioma cell line.

Abstract: We have studied the apoptotic pathway activated in response to marine sponge extracts of Polymastia janeirensis. The effect on intracellular ROS production was also examined. Exposure of U138MG glioma cell line to doses higher than 5 μg/mL has decreased glioma cell viability, with an IC50 <15 μg/mL for both aqueous and organic extracts. However, extracts at higher doses (50 and 100 μg/mL) have stronger cytotoxic effects, decreasing more than 90% of glioma cell viability. The antioxidant Trolox® (100 μM) reversed the cell death percentage induced by extracts at 10 and 25 μg/mL. The type of cell death induced by such high doses was predominantly necrosis, while a high percentage of apoptotic glioma cells was found at 10 μg/mL. Moreover, inhibition of caspase-8 with Z-IETD (a caspase-8 inhibitor) had no effect on the amount of apoptosis induced by 10 μg/mL, but inhibition of caspase-9 with Z-LEHD (a caspase-9 inhibitor) decreased apoptosis. We also observed a dose-dependent increase in ROS production, and similarly to effects observed on viability of glioma cells, and on cell death, higher doses also had more severe effects. Co-treatment with Trolox® significantly reduced ROS production by extracts at doses lower than 50 μg/mL. This is a first report demonstrating that marine sponge extracts of P. janeirensis induce oxidative cell death through a caspase-9 apoptotic pathway.

Activity and expression of ecto-nucleotide pyrophosphate/phosphodiesterases in a hepatic stellate cell line.

Abstract: Nucleotides and nucleosides represent an important and ubiquitous class of molecules that interact with specific receptors, regulate a variety of activities within the liver, and play a role in the pathogenesis of hepatic fibrosis. Ecto-nucleotide pyrophosphatase/phosphodiesterases (E-NPPs) are ecto-enzymes that are located on the cell surface. NPP1, NPP2, and NPP3 (abbreviated as NPP1–3 hereafter) have been implicated in the hydrolysis of nucleotides; together with other ecto-nucleotidases, they control the events induced by extracellular nucleotides. We have identified and compared the expression of E-NPP family members in two different phenotypes of the mouse hepatic stellate cell line (GRX). In quiescent-like hepatic stellate cells (HSCs), E-NPP activity was significantly higher, NPP2 mRNA expression decreased and NPP3 mRNA increased. The differential NPP activity and expression in two phenotypes of GRX cells suggests that they are involved in the regulation of extracellular nucleotide metabolism in HSCs. However, the role of E-NPPs in the liver remains to be clarified.

Effect of temozolomide treatment on the adenine nucleotide hydrolysis in blood serum of rats with implanted gliomas

Abstract: Correspondence Fernanda B Morrone Faculdade de Farmacia Pontificia Universidade Catolica do RS Av. Ipiranga, 6681 P. 12 Bl. C Sala 148 90619900 Porto Alegre,Brasil Phone: +55 51 33203512 E-mail: fbmorrone@gmail.com ATP and other nucleotides and nucleosides are very important signaling molecules under physiological and pathological conditions in the central nervous system. The events induced by extracellular adenine nucleotides are controlled by the action of ectonucleotidases, which hydrolyze ATP into adenosine in the extracellular space. Our group has shown the involvement of the purinergic system in glioma proliferation in different cell types. Low concentrations of ATP induced proliferation Introduction