Not available / text

Multidrug resistance (MDR) in small cell lung cancer is one of the major causes of failures of chemotherapy. MDR is a means of protection of tumor cells against chemotherapeutic drugs. Although the molecular basis of MDR is not fully understood, genes involved in apoptosis may be mutated. Recent finding of a link between over-expression of an apoptotic gene, cyclooxygenase 1 (cox 1), and MDR suggests that cox 1 is involved in the development of MDR phenotype. This research was an attempt to observe whether up-regulation of cox 1 contributes to the MDR phenotype in small cell lung cancer cells. This research ultimately may provide a mechanism to reverse the abberant up-regulation of apoptosis genes associated with multidrug resistance to either eliminate or control reproduction of cancer cells. Real time RT PCR was used to confirm the up-regulation of cox 1 in cultured MDR resistant small cell lung cancer cells (GLC4). The up-regulated cox 1 expression was down-regulated using RNA interference technology (RNAi) by transfection with an anti-cox 1 siRNA. More than 90% transfection of cells was confirmed using confocal microscopy. Down-regulation of cox 1 was validated as the protein expression significantly decreased (P=0.004) from multidrug resistant small cell lung cancer transfected cells compared to multidrug resistant nontransfected cells. There was decrease level of expression of cox 1 in multidrug resistant cells after the knockdown with siRNA specific to cox 1. The decreased level of cox 1 expression and, therefore, Cox 1 production increased the rate of apoptosis in small cell lung cancer cells as indicated by its sensitivity to the doxorubicin. / Department of Biology

The gene, cox-1, is over-expressed in cultured GLC4 small cell lung cancer cells concurrent with the development of multi-drug resistance (MDR) as a result of the use of the chemotherapeutic agent used to combat the cancer, doxorubicin. Prevention of MDR has been a tremendous challenge in cancer research and this research is concerned with abolishment of MDR as a cancer survival strategy. RNA-mediated interference technology (RNAi) was employed using siRNA to decrease cox-1 expression and temporarily restore the susceptibility of the cells to doxorubicin. GLC4 cells are of three types: S (sensitive cells never exposed to doxorubicin); ADR (MDR cells cultured in doxorubicin), and; REV (revertant cells previously cultured in presence of doxorubicin but no longer). REV and ADR cells were transfected with cox-1 siRNA. After 24 h, 1x106cells were used for RNA isolation and 1 μg of RNA was used for RT-PCR to assess down-regulation of cox-1 RNA. RT-PCR results indicated that cox-1 RNA was down-regulated to basal levels seen before exposure to doxorubicin. Ct values for GLC4/ADR and cox-1 down-regulated GLC4/ADR cells were 23 and 34, respectively. The result indicated abundant levels and moderate levels of cox-1 mRNA in the ADR cells and the transfected ADR cells respectively. The relative expression level of cox-1 mRNA was 33% higher in the non-transfected GLCR/ADR cells as compared to the transfected GLCR/ADR cells as shown by the curve. Two hundred thousand cells were used for hemacytometer cell counts in the presence of trypan blue to assess cell viability. cox-1 down-regulation in ADR cells resulted in a significantly higher percentage of non-viable cells (25.4%) as compared to its non-transfected control (20.5%) using a Student’s t-test (*P <0.05). Similarly, fluorescence microscopy confirmed that apoptosis was significantly increased in the ADR cells treated with doxorubicin and cox-1 siRNA simultaneously (69.4%) as compared to its non-transfected control (56.7%) (*= P <0.01). A Western blot analysis performed by Fernando Cuadrado indicated that siRNA transfection decreased the expression of COX-1 by 66% in GLC4/ ADR cells as compared to the non-transfected control using densitometry. However, no conclusive results were obtained using flow cytometry as the flow cytometer was incapable of analyzing the mixed cell population (adherent and suspension) which is a characteristic of this cell line, GLC4. Thus, we have clearly demonstrated that MDR cancer cells can be altered temporarily to become susceptible to doxorubicin, a potentially important finding for the treatment of cancer patients. / Department of Biology

A ação de fosfolipases A2 (FLA2s): miotoxinas (MTs) ?II e III, isoladas de Bothrops asper (VBa) e CB2, de Crotalus durissus terrificus (VCdt) e os venenos brutos, sobre a expressão de ciclooxigenases (COXs) e síntese de prostaglandina (PG) E2 e PGD2 foi avaliada. As MTs e VBa mas não CB2 e nem VCdt induziram a expressão de COX-2 por leucócitos. Em estudos in vitro ocorreram a liberação de PGs e expressão de COX-2, após a incubação de macrófagos (M?s) com FLA22s e, de neutrófilos (N?s) e M?s, com VBa. A CB2 induziu somente a liberação de PGs. A inibição de FLA2 citosólica (cFLA2), diminuiu os níveis de PG induzidos pelas MTs, mas não pela CB2, e não afetou a expressão de COX-2 induzida pelas MTs. O envolvimento do NF-?kB na expressão de COX-2 foi mostrado com inibidores. Em conclusão, MTs, CB2 e VBa estimulam a síntese de PGs in vivo e in vitro e MTs e VBa, mas não CB2, induzem a expressão de COX-2. O VCdt não afeta estes parâmetros. O efeito das MTs sobre a expressão de COX-2 e PGs é mediado pelo NF-kB e pela cFLA2, respectivamente. Os efeitos de CB2 na produção de PGs são independentes de cFLA2s e COX-2. O fato da MT-II ser destituída de atividade enzimática sugere que a atividade catalítica per se, não seja relevante para os efeitos observados. / Action of the phospholipase A2 (PLA22): myotoxins (MTs) -II and -III, from Bothrops asper (BaV) and CB2, from Crotalus durissus terrificus (CdtV) and these venoms on cyclooxygenases (COXs) and synthesis of prostaglandins (PGs) E2 and D2 were studied in vivo and in vitro. Intraperitoneal injection of sPLA22s and BaV but not CdtV released PGD2 and PGE2. MTs and BaV but neither CB2 nor CdtV induced expression of COX-2 by leukocytes. Release of PGs and expression of COX-2 occurred in vitro after incubation of macrophages (M?s) with PLA2 and neutrophils (N?) and M?s with BaV. CB2 induced only PGs release. Inhibition of cytosolic PLA2 (cPLA2), reduced PG levels caused by MTs, but not by CB2 while did not affect MTs-induced COX-2 expression. Involvement of NF-kB in COX-2 was showed using with inhibitors. In conclusion MTs, CB2 and BaV stimulate the synthesis of PGs in vivo and in vitro and MTs and BaV, but not CB2, induce COX-2 expression. VCdt does not affect these parameters. Effect of MTs on COX-2 is mediated by NF-kB, and on PGs by cPLA2. Effects of CB2 on PGs are independent of cPLA2 and OX-2. Since MT-II lacks catalytic activity the PLA2 activity per se is not relevant for activation of this cascade.

Orientadores: Marcio Zaffalon Casati, Francisco Humberto Nociti Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-08T10:03:39Z (GMT). No. of bitstreams: 1 Ribeiro_FernandaVieira_M.pdf: 6226415 bytes, checksum: b38d7ee0ba1cf539da8c71788c69fbad (MD5) Previous issue date: 2007 / Resumo: O objetivo deste estudo foi avaliar a influência de um antiinflamatório não esteroidal inibidor seletivo de COX-2, meloxicam, sobre o reparo ósseo ao redor de implantes de titânio colocados em tíbias de ratos. Foram utilizados 31 ratos Wistar, machos, adultos, os quais receberam um implante dental de titânio em uma das tíbias. Após a colocação dos implantes, os animais foram aleatoriamente incluídos nos seguintes grupos: Controle (n=14): 1 ml/kg de solução fisiológica de cloreto de sódio a 0,9% esterilizada e Teste (n=17): 3 mg/kg de meloxicam, ambos administrados via subcutânea, diariamente, durante 60 dias. Os animais foram mortos após 60 dias da cirurgia de colocação dos implantes. Secções não descalcificadas foram obtidas e avaliadas histometricamente. Foram avaliados os seguintes parâmetros: porcentagem de tecido ósseo em contato direto com a superfície do implante (CD), porcentagem de preenchimento ósseo dentro das roscas do implante (PR) e porcentagem de osso numa região 500 µm adjacente à superfície do implante (OA). Os dados foram obtidos separadamente para região cortical (A) e região medular (B). O teste não paramétrico de Mann-Whitney (a= 5%) foi utilizado para a análise estatística. Os resultados demonstraram que o meloxicam reduziu significativamente o reparo ósseo ao redor dos implantes. Para a região A, diferenças significantes foram observadas com relação ao CD (47,01 ± 10,48 A; 35,93 ± 12,25 B), PR (86,42 ± 3,66 A; 61,58 ± 12,09 B) e OA (96,86 ± 0,96 A; 91,06 ± 3,05 B), entre os grupos controle e teste, respectivamente (p<0,05). Para a região B, a análise dos dados também mostrou diferenças significantes entre os grupos controle e teste, respectivamente (p<0,05), para CD (30,76 ± 13,80 A; 16,86 ± 11,48 B), PR (34,83 ± 8,18 A; 25,66 ± 9,16 B) e AO (15,76 ± 7,05 A; 7,73 ± 4,61 B). Dentro dos limites do presente estudo, concluiu-se que a administração de 3 mg/kg/dia de meloxicam influenciou negativamente o reparo ósseo, tanto no osso cortical quanto medular, ao redor de implantes de titânio inseridos em tíbias de ratos / Abstract: The aim of this study was to investigate the effect of a selective cyclooxygenase-2 inhibitor, meloxicam, on bone healing around titanium implants in rats. Thirty-one adult male Wistar rats were included in this study and one screw-shaped titanium implant was inserted in the tibiae. The animals were randomly assigned to one of the following groups, for daily subcutaneous injections: Control (n=14): 1 ml/kg of saline solution and Test (n=17): 3 mg/kg of meloxicam, each administered daily for 60 days. After the treatment, the animals were sacrificed and undecalcified sections obtained. Bone-to-implant contact (BIC) and bone filling within the limits of of implant threads (BF) and percentage of bone in a 500µm-wide zone lateral to the implant (BL) were obtained and arranged for cortical (zone A) and cancellous (zone B) bone regions. The data were tested by the Mann-Whitney test (a= 5%). Intergroup comparisons demonstrated that meloxicam significantly reduced bone healing around implants. For zone A, significant differences were observed regarding BIC (47.01 ± 10.48 A; 35.93 ± 12.25 B), BF (86.42 ± 3.66 A; 61.58 ± 12.09 B) and BL (96.86 ± 0.96 A; 91.06 ± 3.05 B) for control and test groups, respectively (p<0.05). For zone B, data analysis also showed significant differences among the groups for BIC (30.76 ± 13.80 A; 16.86 ± 11.48 B), BF (34.83 ± 8.18 A; 25.66 ± 9.16 B) and BL (15.76 ± 7.05 A; 7.73 ± 4.61 B) for control and test groups, respectively (p<0.05). In conclusion, within the limits of the present study, 3 mg/kg/day of meloxicam may negatively influence bone healing in the cortical and cancellous bone around titanium implants inserted in rats after continuous administration / Mestrado / Periodontia / Mestre em Clínica Odontológica

Os AINE\'s são frequentemente empregados para o tratamento da dor aguda em gatos, porém, podem ser contraindicados pela propensão em causar efeitos adversos. A dipirona é um antigo analgésico não-opioide extensamente utilizado cujo mecanismo de ação ainda não foi completamente elucidado. O presente estudo prospectivo, randomizado e cego teve como objetivo avaliar o efeito analgésico e o mecanismo de ação via cicloxigenases (COX-1 e 2) da administração por via intravenosa (IV) de dipirona (12,5 mg/kg a cada 12 horas D12,5 ou 25 mg/kg a cada 24 horas D25) ou de meloxicam (0,1 mg/kg a cada 24 horas M) em gatas submetidas à ovariosalpingohisterectomia (OSH) eletiva. Trinta gatas (13 &#177; 5 meses e 2,7 &#177; 0,5 kg) foram avaliadas durante 24 horas após o início do tratamento a partir de ferramentas objetivas e subjetivas da dor. Medicação resgate com cloridrato de tramadol (2 mg/kg, IV) foi instituída quando escores &ge; 5 pela Escala Glasgow. A atividade das COX-1 e 2 foi avaliada a partir da mensuração das concentrações de tromboxano B2 (TXB2) e prostaglandina E2 (PGE2). Efeitos adversos foram registrados e exames laboratoriais, incluindo concentrações séricas de dimetilarginina simétrica (SDMA), foram realizados. As análises estatísticas foram efetuadas com o software GraphPad Prism versão 7.03. O grau de significância estabelecido para os testes foi de 5% (P &lt; 0,05). Mudanças nos parâmetros fisiológicos cardiovasculares não foram clinicamente relevantes, porém as gatas do grupo M apresentaram aumento de frequência cardíaca em relação ao basal (P = 0,0331). A temperatura retal reduziu no momento T1h em todos os grupos (P = 0,0001). Houve um aumento da glicemia no momento T4h no grupo D25 (P = 0,0178) e em T1h no grupo M (P = 0,0205). Apesar de os escores de dor e sedação 9 não diferirem entre grupos, a escala analógica visual revelou aumento em T4h em relação ao basal no D12,5 (P = 0,0415) e os escores de sedação em T1h foram superiores ao basal em todos os tratamentos (P &lt; 0,0001). Não houve diferença quanto ao resgate analgésico, porém duas gatas dos grupos D12,5 (20%) e M (20%) e quatro do D25 necessitaram de medicação resgate. As concentrações de TXB2 foram superiores no grupo M em relação ao D12,5 e D25 em T4h (P = 0,0032 e P &lt; 0,0001, respectivamente) e T24h (P = 0,0070 e 0,0111, respectivamente). Houve redução muito significativa em T1/2h, T4h e T24h quando comparados ao T0h em todos os grupos (P &lt; 0.0001) e ocorreu aumento entre T1/2h e T4h no grupo M (P = 0,0004). As concentrações de PGE2 estimulada por lipopolisacarídeos (LPS) foram superiores em D25 em relação ao M em T4h (P = 0,0479). No grupo D12,5, em T1/2h, esta foram inferiores as de T0h (P = 0,0001) e T4h (P = 0,0112). O mesmo ocorreu no grupo D25 em T0h, T4h e T24h (P &lt; 0,0001, P = 0,001 e 0,0004, respectivamente) enquanto que no M, os momentos T1/2h e T4h apresentaram valores inferiores ao T0h (P = 0,0016 e 0,0075). As concentrações séricas de SDMA do grupo D25 reduziram em T24h quando comparadas as de T0h (P = 0,0322), porém apenas uma gata do grupo M apresentou concentração acima do limite para a espécie. A partir dos resultados observados conclui-se que os protocolos analgésicos instituídos foram efetivos para o controle da dor pós-operatória neste contexto, apresentando inibição não seletiva COX-2 sem causar efeitos adversos e alterações hematológicas, na atividade das enzimas hepáticas e na taxa de filtração glomerular. / NSAIDs are often used for treatment of acute pain in cats, but it may be contraindicated for propensity to cause adverse effects. Dipyrone ia a widely used non-opioid analgesic whose mechanism of action has not yet been fully elucidated. The present prospective, randomized, blind study aimed to evaluate the analgesic effect and mechanism of action of inhibition of cycloxigenases (COX-1 and 2) of intravenous (IV) administration of dipyrone (25 mg/kg q 24 hours or 12.5 mg/kg q 12 hours) or meloxicam (0.1 mg/kg q 24 hours) in cats underwent elective ovariohysterectomy. Thirty cats (13 &#177; 5 months and 2,7 &#177; 0,5 kg) were evaluated for 24 hours after surgical procedure using objective and subjective pain tools. Rescue medication with tramadol hydrochloride (2 mg/kg IV) was administrated when scores &ge; 5 by the Glasgow scale. The activity of COX-1 and 2 was assessed by measuring the concentrations of thromboxane B2 (TXB2) and prostaglandin E2 (PGE2). Adverse effects were recorded and laboratory tests, including serum concentrations of symmetrical dimethylarginine (SDMA), were performed. Data was analyzed with GraphPad Prism version 7.03. Values of P &lt; 0.05 were considered significant. Changes in cardiovascular parameters were not clinically relevant, but the M group presented higher heart rate than basal (P = 0.0331). The rectal temperature reduced at time T1h in all groups (P = 0.0001). There was an increase in blood glucose at time T4h in group D25 (P = 0.0178) and in T1h in group M (P = 0.0205). Although pain and sedation scores did not differ between groups, the visual analogue scale 11 showed an increase in T4h over baseline in D12.5 (P = 0.0415) and sedation scores in T1h were higher than baseline in all treatments (P &lt; 0.0001). There was no difference in the analgesic rescue, but two cats of D12.5 (20%) and M (20%) groups and four from the D25 required rescue medication. The concentrations of TXB2 were higher in M group compared to D12.5 and D25 at T4h (P = 0.0032 and P &lt; 0.0001, respectively) and T24h (P = 0.0070 and 0.0111, respectively) and there was a very significant reduction in T1/2h, T4h and T24h when compared to T0h in all groups (P &lt; 0.0001) and there was an increase between T1/2h and T4h in group M (P = 0.0004). Concentrations of lipopolysaccharide-stimulated PGE2 (LPS) were higher in D25 compared to M in T4h (P = 0.0479). Those in the D12.5 group, in T1/2h, were lower than in T0h (P = 0.0001) and T4h (P = 0.0112). The same occurred in group D25 at T0h, T4h and T24h (P &lt;0.0001, P = 0.001 and 0.0004, respectively) whereas in M, T1/2h and T4h moments presented values lower than T0h (P = 0.0016 and 0.0075). Serum concentrations of SDMA of D25 group decreased in T24h when compared to T0h (P = 0.0322) and only one cat (group M) showed serum concentration above the feline cut-off. In conclusion, the analgesic protocols were effective for the control of postoperative pain in this context, presenting COX-2 non-selective inhibition without causing adverse effects and hematological, liver enzyme activity and glomerular filtration rate alterations.

Neste estudo foram avaliados os efeitos das serinoproteinases PA-BJ e giroxina, isoladas dos venenos das serpentes Bothrops jararaca e Crotalus durissus terríficus, respectivamente, sobre células endoteliais (CEs) em cultura. Os resultados obtidos demonstraram que essas toxinas, nas concentrações utilizadas, não afetaram a viabilidade e a integridade das CEs. Por outro lado, induziram a liberação de PGI2, que foi significativamente reduzida por inibidores não seletivos e seletivos das ciclooxigenases -1 e -2 (COX-1 e -2), mas não afetaram a expressão protéica constitutiva das mesmas. Adicionalmente, foi demonstrado que o antagonista de receptores PAR-1, o SCH 79797, não alterou a liberação de PGI2, induzida pelas toxinas. Em conclusão, essas toxinas, em concentrações não citotóxicas, induziram a liberação de PGI2 a partir de CEs, de modo dependente da ativação das COX-1 e -2. Por outro lado, o receptor PAR-1 não parece ser importante para este efeito, nessas células. / In this study, the effects of PA-BJ and gyroxin, isolated from Bothrops jararaca and Crotalus durissus terrificus snake venoms, respectively, on endothelial cells in culture were investigated. Results showed that neither PA-BJ nor gyroxin affected the integrity of monolayers nor modified ECs viability in the periods of incubation tested. In contrast, these serine proteinases increased the release of prostacyclin from ECs. This effect was inhibited by both non-selective and selective COX-1 and COX-2 inhibitors, but these toxins did not affect the protein expression of COX-1 and -2. Inhibition of the catalytic activity of PA-BJ and gyroxin or pre-incubation of ECs with PAR-1 antagonist did not abrogate the ability of these toxins to induce PGI2 release. These findings demonstrate that these serine proteinases are able to stimulate production of prostacyclin by ECs by a mechanism dependent on stimulation of COX-1 and COX-2 enzyme activity. Moreover, neither enzyme activity of both serine proteinases nor the receptor PAR-1 contribute for this effect on endothelium.

published_or_final_version / abstract / toc / Medicine / Master / Master of Philosophy

Neste estudo foram avaliados os efeitos das serinoproteinases PA-BJ e giroxina, isoladas dos venenos das serpentes Bothrops jararaca e Crotalus durissus terríficus, respectivamente, sobre células endoteliais (CEs) em cultura. Os resultados obtidos demonstraram que essas toxinas, nas concentrações utilizadas, não afetaram a viabilidade e a integridade das CEs. Por outro lado, induziram a liberação de PGI2, que foi significativamente reduzida por inibidores não seletivos e seletivos das ciclooxigenases -1 e -2 (COX-1 e -2), mas não afetaram a expressão protéica constitutiva das mesmas. Adicionalmente, foi demonstrado que o antagonista de receptores PAR-1, o SCH 79797, não alterou a liberação de PGI2, induzida pelas toxinas. Em conclusão, essas toxinas, em concentrações não citotóxicas, induziram a liberação de PGI2 a partir de CEs, de modo dependente da ativação das COX-1 e -2. Por outro lado, o receptor PAR-1 não parece ser importante para este efeito, nessas células. / In this study, the effects of PA-BJ and gyroxin, isolated from Bothrops jararaca and Crotalus durissus terrificus snake venoms, respectively, on endothelial cells in culture were investigated. Results showed that neither PA-BJ nor gyroxin affected the integrity of monolayers nor modified ECs viability in the periods of incubation tested. In contrast, these serine proteinases increased the release of prostacyclin from ECs. This effect was inhibited by both non-selective and selective COX-1 and COX-2 inhibitors, but these toxins did not affect the protein expression of COX-1 and -2. Inhibition of the catalytic activity of PA-BJ and gyroxin or pre-incubation of ECs with PAR-1 antagonist did not abrogate the ability of these toxins to induce PGI2 release. These findings demonstrate that these serine proteinases are able to stimulate production of prostacyclin by ECs by a mechanism dependent on stimulation of COX-1 and COX-2 enzyme activity. Moreover, neither enzyme activity of both serine proteinases nor the receptor PAR-1 contribute for this effect on endothelium.

Abstract not available