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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Estudo do potencial anticâncer de um derivado de Chalcona, 1-(4-Nitrofenil)-3-Fenilprop-2-En-1-Ona, in vitro e in vivo / In vitro and in vivo study of the anticancer potential of a Chalcona derived substance, 1- (4-Nitrofenil)-3- fenilprop-2- en-1-ona

Mousinho, Kristiana Cerqueira January 2010 (has links)
MOUSINHO, Kristiana Cerqueira. Estudo do potencial anticâncer de um derivado de Chalcona, 1-(4-Nitrofenil)-3-Fenilprop-2-En-1-Ona, in vitro e in vivo. 2010. 170 f. Tese (Doutorado em Farmacologia) - Universidade Federal do Ceará. Faculdade de Medicina, Fortaleza, 2010. / Submitted by denise santos (denise.santos@ufc.br) on 2013-09-11T13:50:16Z No. of bitstreams: 1 2012_tese_kcmousinho.pdf: 6059203 bytes, checksum: 15a549b1f793c7ea358dc9fbab7fb2cb (MD5) / Approved for entry into archive by denise santos(denise.santos@ufc.br) on 2013-09-11T16:40:53Z (GMT) No. of bitstreams: 1 2012_tese_kcmousinho.pdf: 6059203 bytes, checksum: 15a549b1f793c7ea358dc9fbab7fb2cb (MD5) / Made available in DSpace on 2013-09-11T16:40:53Z (GMT). No. of bitstreams: 1 2012_tese_kcmousinho.pdf: 6059203 bytes, checksum: 15a549b1f793c7ea358dc9fbab7fb2cb (MD5) Previous issue date: 2010 / The substance 1- (4-Nitrofenil)-3- fenilprop-2- en-1-ona (CG) is a chalcone derivative, synthesized from a chemical reaction between acetophenone and p-nitro benzaldehyde. To evaluate its anticancer potential a pharmacological study of its antitumor properties in selected biological models in vitro e in vivo. CG presented a powerful cytotoxic activity in the 5 tested tumor lines evaluated, inhibiting cell proliferation of the tumor lines in the MTT assay and human peripheral mononuclear blood cells (PMBC) through the Alamar Blue assay. All cell lines showed sensitivity to the treatment with the CG, and the IC50 varied from 1,18 µM in HCT-8 to 3,32 µM in SF-295. The sample presented weak cytotoxic effect (IC50 of 7,07 µM) in cells PMBC, with 72h exposure to CG, compared to HL-60 cells (leukemic cell line), used in the next biological tests. The sample was incubated with the cells during 24h for the majority of the experiments. Additionally, CG did not induce hemolytic effects. The Tripan Blue assay showed a decrease of the cellular viability especially after 24h of incubation of the higher tested concentration (4 µM) with 58,4%. In assays for antiproliferative activity, OA/BE showed in its morphology cells going under apoptosis in the two higher concentrations, whereas the BrdU assay, presented incorporation of the same in the tested concentrations. The morphology analyzed with the May-Grunwald-Giemsa stain showed a decrease of the cellular volume, chromatin condensation and nuclear fragmentation.CG induced apoptosis in HL-60 cells, with participation of the intrinsic pathway and major stimulation of the extrinsic pathway, in a concentration-dependent manner, as observed in the cytoplasmatic membrane integrity, increase of DNA fragmentation and outsourcing of phosphatidylserine. In the cellular cycle analysis, it was observed a stop in the G2/M phase, activating caspases 3, 7, 8 and 9 (the last one in the highest concentration and confirmed by the Western blot assay). It was not observed activation of Cytochrome c. CG was not capable to induce mutagenic/genotoxic processes (comet assay and micronucleus in vitro). In the in vivo antitumor activity assay, tumor inhibition was observed in the tested doses (25 and 50mg/Kg/day, oral intake) of 54,85 and 69,11%, respectively . The doses of CG caused cellular swelling and the arise of inflammatory focus in the parenchyma or hepatic/renal stroma, focal nephrotoxic necrosis, microvesicular steatosis, hemosiderin pigments, hyperplasia of Kupffer cells, congestion of the red pulp and disorganization of the splenic lymphoid follicles. Furthermore, the biochemical indices had shown increase of AST and reduction of urea (25mg/Kg/day of CG), reduction of ALT (25mg/Kg/day of 5-FU and CG); hematologic alterations showed leukopenia and thrombocytopenia (5-FU), increase of total leukocytes (50mg/Kg/day of CG), increase of neutrophils and lymphocytes in all treated groups. All results led us to emphasize that CG possesses great potential as a promising molecule for its anticancer properties. / A substância 1-(4-Nitrofenil)-3-fenilprop-2-en-1-ona (CG) é um derivado de chalcona, sintetizado a partir da reação química entre a acetofenona e para-nitro benzaldeído. Para avaliar o seu potencial anticâncer foi realizado um estudo farmacológico de suas propriedades antitumorais em vários modelos biológicos in vitro e in vivo. A CG apresentou potente atividade citotóxica nas 5 linhagens tumorais testadas, inibindo a proliferação das células tumorais pelo ensaio do MTT e em células mononucleares do sangue periférico (PMCB) humano através do ensaio do Alamar blue. Todas as linhagens mostraram sensibilidade ao tratamento com a CG, e a CI50 variou de 1,18µM em HCT-8 a 3,32µM em SF-295. O composto apresentou fraca citotoxicidade (CI50 igual a 7,07µM) nas células PBMC, com exposição a CG em 72h, em relação às células de HL-60, utilizada como modelo nos demais testes biológicos. O tempo de encubação com o composto foi de 24h na maioria dos experimentos. Adicionalmente, a CG não induziu efeitos hemolíticos. O ensaio de exclusão por azul de Tripan revelou diminuição da viabilidade celular principalmente após 24h na maior concentração testada (4µM) com 58,4%. Para os testes de atividade antiproliferativa, LA/BE mostrou em sua morfologia células em apoptose nas duas maiores concentrações, enquanto que o BrdU, apresentou incorporação do mesmo nas concentrações testadas. A morfologia analisada por May-Grunwald-Giemsa mostrou redução do volume celular, condensação da cromatina e fragmentação nuclear. Adicionalmente, a CG induziu apoptose em células leucêmicas HL-60, com participação das vias intrínseca e maior estímulo da via extrínseca, de maneira concentração-dependente, como observado na integridade da membrana citoplasmática, aumento da fragmentação do DNA e externalização da fosfatidilserina. Na análise do ciclo celular, foi observado parada na fase G2/M, sendo ativada as caspases 3, 7, 8 e 9 (a última na maior concentração e confirmada pelo teste do Western blot). Não houve ativação do Citocromo c. A CG não foi capaz de induzir processos genotóxicos/ mutagênicos (testes do cometa e micronúcleo in vitro). No ensaio de atividade antitumoral in vivo, observou-se inibição tumoral nas doses testadas (25 e 50mg/Kg/dia, via oral) de 54,85 e 69,11% respectivamente. As doses de CG causaram tumefação celular e o surgimento de focos inflamatórios no parênquima ou estroma hepático/renal, necrose nefrotóxica focal, esteatose microvesicular, pigmentos de hemossiderina, hiperplasia das células de Kupffer, congestão da polpa vermelha e desorganização dos folículos linfóides esplênicos. Além disso, os índices bioquímicos mostraram aumento do AST e diminuição da uréia (CG 25mg/Kg/dia), diminuição do ALT (5-FU e CG 25mg/Kg/dia); as alterações hematológicas mostraram leucopenia e plaquetopenia (5-FU), aumento dos leucócitos totais (CG 50mg/Kg/dia), aumento de neutrófilos e linfócitos em todos os grupos tratados. Todos os resultados nos levam a enfatizar que a CG possui grande potencialidade como molécula promissora por suas propriedades anticâncer.
2

Identificació de noves dianes terapèutiques en neoplàsies limfoides

Xargay i Torrent, Sílvia 29 October 2012 (has links)
El limfoma de cèl•lules de mantell (MCL) i la leucèmia limfàtica crònica (CLL) són dues neoplàsies limfoides fins al moment incurables, per la qual cosa requereixen la recerca de nous fàrmacs. La identificació de noves dianes terapèutiques per al MCL i la CLL, i del mecanisme molecular d’actuació d’aquests fàrmacs en aquestes neoplàsies, té una gran rellevància translacional. El concepte de medicina personalitzada està basat en l’ús de teràpies dirigides a través d’un coneixement profund dels mecanismes moleculars d’acció d’aquests agents. Amb l’augment del coneixement sobre l’etiologia del càncer, s’han descobert noves dianes alterades específicament en les cèl•lules tumorals. Entre elles, la sobreexpressió de les HDACs, que provoca un estat epigenètic aberrant a la cèl•lula. Això ha motivat el desenvolupament del vorinostat, un inhibidor de les HDACs. Els resultats obtinguts demostren el vorinostat és efectiu i selectiu per a les cèl•lules tumorals de MCL. A nivell molecular, el vorinostat en el MCL indueix l’acetilació de les histones de la regió promotora dels gens de les proapoptòtiques de la família de Bcl-2 BH3-only BIM, BMF i NOXA, que són activats transcripcionalment. Totes tres proteïnes, Bmf, Bim i Noxa, cooperen en el procés d’apoptosi. A més, el vorinostat és sinèrgic amb l’agent que mimetitza les BH3-only, ABT-263. En els últims anys, s’ha identificat un gran nombre de cinases, que regulen moltes vies de supervivència i proliferació cel•lulars, que estan específicament activades i sobreexpressades en cèl•lules tumorals. En particular, recentment les cinases associades al receptor de cèl•lules B (BCR) han esdevingut un focus d’atenció important, ja que està activament implicat en la patogènesi de les neoplàsies limfoides. En aquesta tesi, hem analitzat l’efecte anti-tumoral de l’inhibidor multi-cinasa sorafenib en la CLL i el MCL. Els nostres resultats confirmen que el sorafenib indueix apoptosi selectiva en cèl•lules de CLL i de MCL, fins i tot en els casos de més mal pronòstic de la CLL. A nivell molecular, els nostres resultats han demostrat que el sorafenib indueix una desfosforilació ràpida, sostinguda i simultània de les cinases associades al BCR, Syk i de la família Src cinases. En la CLL i el MCL a temps d’incubació molt curts, el sorafenib provoca una disminució traduccional de l’anti-apoptòtica Mcl-1 alhora que de ciclina D1, sobreexpressada en el MCL. Tant Mcl-1 com ciclina D1 participen en l’apoptosi induïda per sorafenib, la disminució de Mcl-1 altera directament els senyals anti-apoptòtics, mentre que el sorafenib, a més de disminuir els nivells de ciclina D1, també allibera Bax del segrestament per part de ciclina D1, finalment activant mecanismes d’apoptosi caspasa-dependents i independents com AIF. El sorafenib també modula les interaccions del microambient amb la CLL i el MCL. En aquest sentit, s’ha demostrat que el sorafenib bloqueja la migració induïda per la quimiocina CXCL12 via inhibició de FAK, una cinasa substrat de Src que regula i promou la invasió. El complex Src-FAK afecta múltiples proteïnes, com ara les del citoesquelet d’actina. En consistència, el sorafenib bloqueja la reorganització del citoesquelet en cèl•lules de MCL estimulades amb CXCL12. Les cèl•lules estromals del microambient dels teixits, com ara el moll d’os i els teixits limfoides secundaris, interaccionen amb el tumor i en promouen el seu creixement i resistència a fàrmacs. En aquest context, s’ha demostrat que, en presència de l’estroma del microambient, les cèl•lules de MCL i CLL esdevenen resistents als agents quimioterapèutics habituals i el sorafenib és capaç de resensibilitzar-les. Tant la proliferació com l’activació del BCR en la CLL són majors en el gangli limfàtic que en sang. En aquest sentit, s’ha demostrat que el sorafenib és més efectiu en cèl•lules de CLL derivades de gangli limfàtic que les respectives derivades de moll d’os i de sang perifèrica. L’estimulació del BCR en la CLL també provoca la secreció de les citocines atraients de cèl•lules accessòries CCL3 i CCL4, que el sorafenib bloqueja amb eficiència. Globalment, els treballs que constitueixen aquesta tesi doctoral suposen una contribució important en el coneixement del mecanisme molecular d’acció del vorinostat i el sorafenib, fàrmacs nous que podrien ser efectius per al tractament d’aquestes dues entitats, el MCL i la CLL. / Mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL) are two incurable B-lymphoid malignancies, thus new therapeutic strategies are required. In the recent years, anti-tumor therapy has focused on pathways specifically altered in cancer cells. Among them, overexpression of histone deacetylases (HDACs) is a common feature. This led to the development of the HDAC inhibitor vorinostat. This thesis has shown that vorinostat could become a new therapeutic approach for MCL. The results show that vorinostat is effective and selective for MCL cells. The molecular mechanism of action of vorinostat involves acetylation of the histones in the gene promoter of the pro-apoptotic BH3-only from Bcl-2 family, BMF, BIM and NOXA, which induces its transcriptional activation. The respective proteins cooperate in the apoptosis induction. Moreover, vorinostat synergizes with the BH3-only mimetic ABT-263 in MCL. Plenty of kinases that have been recognized to regulate survival and proliferation pathways are overexpressed in tumor cells. In this work, we analyzed the anti-tumor effect of sorafenib, a multi-kinase inhibitor approved by the FDA, in CLL and MCL. Sorafenib induces selective apoptosis in CLL and MCL cells, being also effective in poor prognosis cases of CLL. At the molecular level, sorafenib dephosphorylates the B-cell receptor (BCR) associated kinases, specifically Syk and the Src family kinases. In CLL and MCL, sorafenib inhibits Mcl-1 and cyclin D1 translation. Mcl-1 downregulation is directly impairing anti-apoptotic signals. As for cyclin D1, sorafenib releases Bax from cyclin D1 sequestering. Both processes are involved in apoptosis induction, which occurs through caspase-dependent and independent mechanisms. In addition, sorafenib blocks CXCL12-induced migration and actin polymerization via FAK inhibition, a Src kinase substrate that regulates migration. Stromal cells from the microenvironment interact with and promote tumor growth and drug resistance. In this context, MCL and CLL cells become resistant to conventional chemotherapeutic drugs in the presence of stromal microenvironment, which is counteracted by sorafenib. Activation of the BCR and proliferation in CLL cells is higher in the lymph node microenvironments, a setting where sorafenib has been demonstrated to be more effective. BCR stimulation also leads to CCL3 and CLL4 chemoattractant cytokines secretion in CLL, that sorafenib blocks efficiently. Overall, this thesis is an important contribution to the understanding of the molecular mechanism of action of vorinostat and sorafenib, new drugs that might be effective for the treatment of these two entities, MCL and CLL.

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