Os agentes antineoplásicos são considerados drogas de risco, ou seja, aquelas que podem ocasionar efeitos como genotoxicidade, carcinogenicidade , teratogenicidade ou alteração na fertilidade e a exposição dos profissionais de saúde constitui-se em grande preocupação do ponto de vista de saúde ocupacional. Precedendo o seu emprego na terapia oncológica, estes medicamentos devem ser submetidos a análises físicas, químicas e biológicas para avaliação da qualidade, sendo que estes testes geram considerável volume de resíduos que também requerem tratamento. O objetivo deste trabalho foi avaliar a eficácia de diferentes métodos de inativação para as moléculas de cisplatina, doxorrubicina e paclitaxel em solução injetável, utilizando cromatografia líquida de alta eficiência (avaliação química) e teste de citotoxicidade in vitro (avaliação biológica). Foram avaliados os inativantes Asepto 75® (solução a 0,5%), hipoclorito de sódio (solução a 10%) e tiossulfato de sódio (solução a 10%). Os ativos ficaram expostos aos inativantes por períodos que variaram de 0 a 6 horas. Os resultados demonstraram que o asepto 75 é eficiente para a inativação química e biológica dos três ativos, sendo o tempo de exposição fator determinante para a degradação química da cisplatina. Os graus de citotoxicidade variaram de nenhum a leve (IZ= 0 a 1). O hipoclorito de sódio possui um grau de citotoxicidade por si só, porém foi eficaz na inativação química dos três ativos. Já o inativante tiossulfato de sódio se mostrou eficaz na in ativação química da cisplatina, não tendo efeito sobre a doxorrubicina ou sobre o paclitaxel. Os resultados da avaliação in vitro mostraram-se compatíveis com os da avaliação química. Conclui-se que a inativação dos princípios ativos previamente ao descarte é eficaz para reduzir os riscos ocupacionais e ambientais das drogas citotóxicas. / The anti-neoplastic agents are considered risk drugs, that is, the ones that can cause effects, such as genotoxicity, carcinogenicity, teratogenicity or change in fertility. Because of these factors, the exposure of the health care professionals are a great concern of occupational health. Before the use of the oncological therapy, these drugs should be undergone to the physical, chemical and biological tests for the quality evaluation, considering that these test also produce a considerable amount of waste which also demand treatment. The aim of this work is to evaluate the efficacy oh the different methods of inactivation for the cisplatine molecules, doxorubicine and paclitaxel in injection solutions. Using high performance liquid chromatography (chemical evalution) and in vitro citotoxity test (biological evaluation). It has been evaluated Asepto 75 degradant (aqueous solution at 0,5%), sodium hypochlorite (aqueous solution at 10%) and sodium thyosulfate (aqueous solution at 10%). The drugs were exposed to the degradants in periods that ranged from 0 to 6 hours. The results have been demonstrated that asepto 75 is efficient for the chemical and biological inativation of the drugs, and the time of exposition is determinant for the chemical degradation of cisplatin. The citotoxicity grades have ranged from \"none\" to \"slight\". The sodium hypochlorite has a toxicity grade for itself, although it was effective in the chemical degradation of the three drugs. Yet the sodium thiosulfate degradant has demonstrated to be effective in the chemical inativation of cisplatin, not having effects over doxorubicin or paclitaxel. The results of in vitro evaluation have been compatible with the chemical evaluation. It concludes that the inactivation of the drugs before the waste is effective to reduce the occupational and environmental risks of citotoxic drugs.

O câncer de mama representa um grave problema de saúde pública. Dentre os fármacos empregados, destaca-se o paclitaxel, um agente citotóxico eficaz, porém associado a severos efeitos colaterais. A metformina hidrocloreto tem obtido resultados promissores para o tratamento de neoplasias, porém é bastante hidrofílica, fator limitante da biodisponibilidade. A rapamicina tem demonstrado sinergismo com paclitaxel e potente atividade antitumoral. Todavia, é um fármaco lipofílico e possui desvantagens. Sistemas nanoestruturados de fármacos como lipossomas PEGlados são largamente empregados para a melhora da farmacocinética e potencialização da ação terapêutica. Ademais, a funcionalização de lipossomas com anticorpos monoclonais pode permitir a entrega seletiva do fármaco encapsulado à célula alvo. No presente trabalho objetivou-se desenvolver e caracterizar lipossomas e imunolipossomas funcionalizados com trastuzumabe, contendo paclitaxel, metformina hidrocloreto e/ou rapamicina, bem como avaliar as formulações através de estudos in vitro e in vivo. Os resultados mostraram que a metformina hidrocloreto foi encapsulada com baixa eficiência, menor que 20%, ao passo que paclitaxel e rapamicina puderam ser co-encapsulados com adequados valores de eficiência de encapsulação, equivalente a 56,32% para paclitaxel e 73,31% para rapamicina, e tamanho de partícula nanométrico, de 136,95 nm em composição biocompatível baseada em SPC:Col:DSPE-PEG(2000). Os dois fármacos apresentaram liberação lenta, e foram convertidos às formas molecular e amorfa, respectivamente para paclitaxel e rapamicina quando encapsulados. Os imunolipossomas foram funcionalizados com elevada eficiência com trastuzumabe e mantiveram o tamanho nanométrico, com adequados valores de encapsulação dos fármacos. Ainda, mostrou-se o sinergismo entre paclitaxel e rapamicina coencapsulados em lipossomas em células triplo negativas (4T1) e houve sinergismo entre os dois fármacos, mediado pelo anticorpo em imunolipossomas frente à linhagem celular HER2 positiva (SKBR3), em virtude do aumento do uptake celular mediado pelo trastuzumabe. Finalmente, os resultados obtidos in vitro foram confirmados in vivo, sendo que os lipossomas com paclitaxel e rapamicina coencapsulados foram capazes de controlar o crescimento tumoral em modelo de câncer de mama triplo negativo, ao passo que o imunolipossoma com os dois fármacos permitiu o controle do crescimento de tumores xenográficos HER2 positivos, cuja média de volume tumoral correspondeu a 25,27%, 44,38% e 47,78% das médias dos volumes tumorais de controle negativo, positivo e lipossoma, respectivamente. Portanto, a formulação desenvolvida nesse trabalho tem potencial para ser avaliada em estudos clínicos. / Breast cancer represents a severe public health problem. Among the drugs used in the treatment, paclitaxel is an effective cytotoxic drug, but associated with side effects. Hydrocloride metformin has shown promising results for cancer treatment, however it is very hydrophilic, a limiting factor for bioavailability. Rapamycin has demonstrated synergism with paclitaxel and potent anticancer activity, though it is a lipophilic drug with drawbacks that compromise its bioavailability. Nanostructured drug delivery systems, such as PEGylated liposomes are largely employed for pharmacokinetics improvement and enhancement of therapeutic effect. Furthermore, the functionalization of liposomes with monoclonal antibodies enables the selective delivery of the loaded drug to the target cell. In the present work, we aimed to develop and characterize liposomes and immunoliposomes functionalized with trastuzumab, containing paclitaxel, hydrocloride metformin and/or rapamycin, as well as to evaluate the formulations through in vitro and in vivo studies. The results showed that hydrocloride metformin was encapsulated with low efficiency, less than 20%, on the other hand paclitaxel and rapamycin could be co-loaded with suitable values of encapsulation efficiency, 56.32% for paclitaxel and 73.31% for rapamycin and nanometric particle size, 136.95 nm, based on a SPC:Chol:DSPE-PEG(2000) composition. The two drugs displayed slow release, and were converted to molecular and amorphous form, respectively for paclitaxel and rapamycin when encapsulated. The immunoliposomes were developed with high efficiency with trastuzumab and kept the nanometric size, with adequate encapsulation of drugs. Moreover, herein it was shown the synergism between paclitaxel and rapamycin co-loaded in liposomes in triple negative cells (4T1) and there was synergism between the two drugs mediated by the antibody in immunoliposomes in the HER2-positive cell line (SKBR3), due to the improved cell uptake mediated by trastuzumab. Finally, the results obtained in vitro were confirmed in vivo. Co-loaded paclitaxel and rapamycin were able to control tumor growth in a triple negative breast cancer animal model, while the immunoliposome containing the two drugs allowed for better control of tumor growth in a HER2-positive breast xenograft model, whose average tumor volume corresponded to 25.27%, 44.38% and 47.78% of the tumor volumes of positive control, negative control and liposome, respectively. Therefore, the formulation developed herein has potential to be evaluated in clinical trials.

O câncer de mama constitui o segundo tipo de câncer mais frequente no mundo e o mais comum entre as mulheres, devido ao seu alto grau de malignidade. A quimioterapia é utilizada no tratamento de câncer de mama com presença de metástase, dentre os fármacos mais utilizados está o paclitaxel, que atua na desestabilização dos microtúbulos na divisão celular, levando a célula neoplásica a apoptose, porém, o paclitaxel é uma molécula extremamente lipofílica, solubilizada em Cremophor® EL, um tensoativo altamente tóxico utilizado na formulação comercial. O objetivo deste trabalho foi desenvolver complexos dendriméricos com paclitaxel para a otimização da terapia do câncer de mama. Para a quantificação do paclitaxel nos sistemas de liberação desenvolvidos foram validados métodos analíticos por espectrofotometria UV-Vis e por cromatografia líquida de alta eficiência. Os métodos foram seletivos, linear, precisos e exatos. Para a obtenção de uma formulação concentrada os complexos foram liofilizados. O complexo PAMAM-G4-NH2-Paclitaxel foi obtido em diversos meios reacionais, com diferentes faixas de pH, sendo o tampão Hepes, pH 7,4, e água; os meios que obtiveram melhores resultados de complexação, posteriormente foram analisados por DLS e NTA, com diâmetro médio de partícula em 160 nm e potencial zeta catiônico. A caracterização do complexo obtido foi realizada por análises de espectrofotometria no infravermelho e ressonância magnética nuclear. O estudo in vitro de liberação do paclitaxel a partir dos complexos dendriméricos foi realizado utilizando membrana de acetato de celulose e quantificação por CLAE. O perfil de liberação demonstrou que após 156 horas, no máximo 35% do fármaco foi liberado. A liberação lenta representa uma vantagem para o tratamento de tumores sólidos, pois idealmente o sistema de liberação deve manter o fármaco encapsulado durante a circulação sanguínea e liberá-lo uma vez acumulado passivamente no sítio tumoral. A citotoxicidade foi avaliada na linhagem tumoral 4T1, através do ensaio do MTT. O complexo PAMAM-G4-NH2-Paclitaxel apresentou citotoxicidade 5 vezes maior que a formulação comercial. Na avaliação antitumoral in vivo do complexo, foram avaliados a curva do crescimento tumoral, o registro de peso, a sobrevivência dos animais e a proliferação celular com o anticorpo ki 67. O complexo dendrimérico teve efeito estatisticamente significativo na redução do volume tumoral e, através da análise de imunohistoquimica foi confirmada a redução da proliferação celular. Portanto, o complexo PAMAM-G4-NH2-Paclitaxel pode representar uma estratégia promissora para o tratamento de câncer de mama e posteriormente deverá ser avaliada por meio de estudos clínicos. / Breast cancer is the second most common type of cancer worldwide and the most common among women, due to its high degree of malignancy. Chemotherapy is used to treat breast cancer metastasis, among the most widely used drugs are paclitaxel, which operates in the microtubules destabilization in cell division, resulting in neoplastic cell apoptosis, however, paclitaxel is a highly lipophilic molecule which is solubilized in Cremophor® EL, a highly toxic surfactant used in the commercial formulation. The aim of this study was to develop dendrimeric complex with paclitaxel for the optimization of breast cancer therapy. To quantify the paclitaxel in the developed delivery systems, the analytical method was validated by UV-Vis spectrophotometry and high-performance liquid chromatography. The methods were selective, linear, accurate and precise. To obtain a concentrated formulation, the complexes were lyophilized. The PAMAM-G4-NH2-paclitaxel complex was obtained in various reaction media with different pH ranges, with the HEPES buffer, pH 7.4, and water. The media with obtained the best complexation were subsequently analyzed by DLS and NTA, and the mean particle diameter was 160 nm with a cationic zeta potential. The characterization of the obtained complex was performed by infrared and nuclear magnetic resonance spectrophotometric analysis. The in vitro release study of paclitaxel from the dendrimeric complex was evaluated using membranes of cellulose acetate and quantified by HPLC. The release profile showed that after 156 hours at most 35% of the drug was released. The extended release is an advantage for the solid tumors treatment, because ideally the release system should keep the drug encapsulated during blood circulation and release it over time passively accumulated in the tumor site. Cytotoxicity was assessed in tumor cell line 4T1, using the MTT assay, the PAMAM-G4-NH2 paclitaxel complex showed cytotoxicity 5 times greater than the commercial formulation. In in vivo antitumor evaluation of the complex were evaluated curve of tumor growth, the weight record, the animal survival and cell proliferation with the antibody ki 67. Dendrimer complex had statistically significant effect in reducing tumor volume and through the immunohistochemical analysis the results were confirmed the reduction of cell proliferation. Therefore, the PAMAM-G4- NH2-paclitaxel complex can represent a promising strategy for the breast cancer treatment and should be further evaluated by means of clinical studies

Orientador: Edgard Graner / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-24T18:26:23Z (GMT). No. of bitstreams: 1 Moreira_FernandadosSantos_M.pdf: 1478167 bytes, checksum: 57f6f26580823a79292af5a274beaa2d (MD5) Previous issue date: 2014 / Resumo: A ácido graxo sintase (FASN) é a principal enzima envolvida na lipogênese neoplásica e apontada como uma oncoproteína metabólica por favorecer o crescimento e sobrevivência das células tumorais, nas quais sua expressão é em geral elevada. Vários são os compostos capazes de inibir a atividade de FASN, dentre eles o orlistat (Xenical®), que possui efeitos antineoplásicos em cânceres de mama e próstata e nos melanomas. O carcinoma espinocelular (CEC) representa aproximadamente 90% de todas as neoplasias malignas que acometem a cavidade oral, sendo diagnosticado em estágios avançados em grande parte dos casos. Nestes pacientes, geralmente com metástases, é realizada uma abordagem sistêmica com agentes quimioterápicos como a cisplatina, o 5-fluorouracil (5-FU) e o paclitaxel, de maneira isolada ou combinada. Este trabalho tem como objetivo investigar in vitro se cisplatina, 5-FU ou paclitaxel potencializam o efeito antitumoral do orlistat no CEC oral. Para isto, células de CEC de língua altamente metastáticas (SCC-9 LN1) foram tratadas com estas drogas isoladamente ou combinadas com orlistat e avaliadas com relação às taxas de apoptose e necrose, progressão do ciclo celular e secreção de VEGFA e VEGFA165b. As maiores taxas de apoptose foram encontradas com o uso da combinação de orlistat com paclitaxel, após 48 horas de tratamento. Com relação ao ciclo celular, houve acúmulo de células na fase S com a combinação de orlistat com cisplatina e na fase G2 com a combinação de orlistat com paclitaxel. O tratamento das células SCC-9 LN1 com os agentes quimioterápicos reduziu a secreção dos fatores VEGFA e VEGFA165b, em comparação ao tratamento com orlistat isolado ou em combinação. Em conjunto, estes resultados mostram a existência de sinergismo na combinação de orlistat com paclitaxel com evidente potencialização do efeito pró-apoptótico nas células derivadas de CEC oral metastático / Abstract: Fatty acid synthase (FASN) is the main enzyme involved in the neoplastic lipogenesis. The expression of FASN is elevated in many tumor cells, suggesting a role as a metabolic oncoprotein, with the ability to promote growth and survival of tumor cells. There are several compounds that inhibit FASN activity, including orlistat. Orlistat has evident antineoplastic effects in breast and prostate cancers, as well as melanomas. Oral squamous cell carcinoma (OSCC), corresponds to approximately 90% of all cancers that affect the oral cavity, and is diagnosed in advanced stages in most cases. Distant metastases of OSCC are systemically treated with chemotherapeutic agents, such as cisplatin, 5-fluorouracil (5-FU) and paclitaxel. This study aims to investigate the in vitro antitumor effect of orlistat combined with cisplatin, 5-FU and/or paclitaxel in OSSC cells. Highly metastatic tongues squamous cell carcinoma cells (SCC-9-LN1) were treated with these drugs separately or combined with orlistat, in concentrations close to their respective IC50. Next, the cultures were evaluated regarding the rates of cell death (apoptosis and necrosis), cell cycle progression and the secretion VEGFA and VEGFA165b. The highest rate of apoptosis was observed with the combination of orlistat and paclitaxel, after 48 hours of treatment. Cell cycle analysis assay demonstrate as an accumulation of cells SCC-9 LN1 in the S phase, after incubation with the combination of orlistat with cisplatin, and in the G2 phase with orlistat plus paclitaxel. The 5-FU alone, promoted accumulation of cells in the G1/S. Additionally, secretion of VEGFA and was VEGFA165b was inhibited in SCC-9-LN1cells by the combined treatments. These results demonstrate the synergism existence of the mixture orlistat and paclitaxel with potentiation of their pro-apoptotic effects in SCC-9 LN1 cells / Mestrado / Estomatologia / Mestra em Estomatopatologia

Parmi les nombreux agents thérapeutiques utilisés en oncologie, le paclitaxel (Taxol®) est sans doute celui qui a suscité le plus d'intérêt. Il est utilisé en clinique pour le traitement des cancers de l'ovaire, du sein et des poumons. Il agit comme poison du fuseau mitotique en favorisant l'assemblage de la tubuline en microtubules et en stabilisant le polymère formé. Initialement extrait de l'if du Pacifique (Taxus Brevifolia) puis obtenu par hémisynthèse à partir de la 10-déacétylbaccatine III, il est aujourd'hui produit par un procédé biotechnologique de fermentation de cellules végétales. Le paclitaxel possède une structure chimique complexe basée sur un squelette tétracyclique taxane. Une approche visant à remplacer ce squelette taxane par une structure chimique plus simple a été entreprise afin d'identifier des mimes du paclitaxel. L'identification d'un fragment chimique (fragment based drug design) dérivé de la proline par une étude de modélisation moléculaire a permis de développer de nouvelles séries de mimes du paclitaxel. Parallèlement, le remplacement du squelette taxane par une matrice peptidique cyclique utilisant des dérivés de la proline a été réalisé. Les études de modélisation moléculaire, la synthèse des mimes du paclitaxel et leur évaluation biologique seront présentées. / Among the many therapeutic agents used in oncology, paclitaxel (Taxol®) is probably the one that generated the most interest. It is used clinically for the treatment of ovarian, breast and lung cancers and acts as a mitotic spindle poison by promoting the assembly of tubulin into microtubules and stabilizing the polymer formed. Initially extracted from the Pacific yew (Taxus Brevifolia) and obtained by semi-synthesis from 10-deacetylbaccatin III, it is now produced by a biotechnological process of cell plant fermentation. Paclitaxel has a complex chemical structure based on a tetracyclic taxane skeleton. A process to replace the taxane skeleton with a simpler chemical structure was undertaken to identify paclitaxel mimics. The identification of a chemical fragment (fragment based drug design) derived from proline by a molecular modeling study has led to the design of a new series of paclitaxel mimics. Meanwhile, replacing the taxane skeleton by a cyclic peptide scaffold using proline derivatives was performed. Molecular modeling studies, synthesis of paclitaxel mimics and biological evaluation will be presented.

Les nano-objets ou nanoparticules sont des systèmes de taille nanométrique. Dans le domaine de l’oncologie, ils sont capables de transporter des agents anticancéreux et/ou des macromolécules comme des gènes ou des protéines, de sorte qu’ils s’accumulent préférentiellement dans le tissu tumoral. Ainsi, les nanoparticules ont pour but de diminuer la quantité de principe actif libre dans l’organisme, responsable de toxicités. Elles permettent en clinique d’améliorer la balance bénéfice/risque des agents de chimiothérapies conventionnels. Ce sont de véritables plateformes qui permettent de s’affranchir de certains excipients toxiques contenus dans la formulation du paclitaxel (Cremophor El). Ainsi, au cours de ce travail nous nous sommes intéressés dans un premier temps aux nanoparticules d’or (Au-NP) produites par ablation laser femtoseconde. Nous avons ainsi caractérisé ces Au-NP sur le plan physico-chimique et biologique, et mis en évidence leur internalisation et leur innocuité. Dans un deuxième temps, nous avons évalué l’efficacité pharmacologique de conjugués dendron-paclitaxel sur des cultures cellulaires 2D et 3D et mis en avant la libération prolongée intracellulaire du paclitaxel et son effet retard. Compte-tenu des propriétés observées, ces nanoparticules sont de bons candidats pour un futur développement. En effet, la liaison de ces deux nanostructures entre elles permettra l’obtention d’un nano-objet aux propriétés de théranostiques. / Nano-objects or nanoparticles can be readily fabricated with their size being controlled typically in the range of 1–100 nm. In the field of oncology, they can be used for drug delivery, as their composition/structure may be engineered to load anticancer drugs, macromolecules or proteins. Indeed, the delivery of anticancer drugs through a nanoparticle-based platform offers many attractive features. Nanoparticle-based drugs are synthetized to significantly improve the benefit/risk ratio of conventional chemotherapeutics. They allow overcoming some toxic excipients in the formulation of paclitaxel (Cremophor El). In this work, we first studied the physico-chemical and biological properties of Au-NPs synthetized by femtosecond laser ablation and we investigated their safety and cellular uptake. Second, we evaluated the anticancer activity of dendron-paclitaxel conjugates in 2D and 3D cell cultures and showed a delayed effect of this new formulation. Based on these results, the studied nanoparticles are good candidates for future development. By combining the two nano-objects, we will obtain nanoparticles with theranostic properties.

Les dérivés de platine (cisplatine, oxaliplatine et carboplatine) et les taxanes (paclitaxel et docétaxel) font partie des grandes familles d’agents anticancéreux couramment utilisés en chimiothérapie. Ils permettent de traiter les tumeurs solides telles que les cancers de l’ovaire, du poumon, de la prostate, du sein, tête et cou. Cependant, ils sont à l’origine d’importantes neuropathies périphériques qui peuvent devenir irréversibles et laisser les patients avec des séquelles importantes. Il s'agit de vertiges, acouphènes, engourdissements, pertes de sensibilité, allodynies au toucher ou aux variations de température. Ces effets secondaires sont fortement contraignants et réduisent considérablement la qualité de vie de 30 à 50% des patients. L'importance clinique est considérable, puisque cela conduit environ 1/3 des patients atteints à l’arrêt et/ou au changement des traitements, bien que ceux-ci soient efficaces sur les tumeurs.Les dérivés de platine sont des agents pontants : leurs interactions avec les bases purines de l’ADN forment des adduits, qui vont être reconnus par des protéines de dommage à l’ADN, conduisant à la mort cellulaire. Les taxanes bloquent la dépolymérisation des microtubules, ce qui induit la mort des cellules en divisions. Le fait que deux mécanismes d’action antitumorale très différents provoquent, à court ou à moyen terme, les mêmes neuropathies périphériques, est paradoxal et n’a pas d’explication.Le but de mon projet de thèse était d’étudier le ou les mécanismes à l’origine de ces neuropathies et de développer une formulation visant à les réduire. Pour cela, j’ai étudié les effets des taxanes et dérivés de platine sur les canaux ioniques, impliqués dans la nociception. Ces canaux ioniques, appelés nocicepteurs, sont transcrits dans les corps cellulaires des ganglions spinaux (DRG), avant d’être principalement adressés à l’extrémité des nerfs périphériques. Ils détectent les stimuli mécaniques, thermiques et chimiques et génèrent ou transmettent les potentiels d’action correspondants. Le fait de perturber l’expression génique et/ou l’activité de ces nocicepteurs, aura donc pour conséquence de modifier les seuils de sensibilité et la transmission de différents stimuli.Mes résultats ont permis de quantifier dans des cultures primaires de DRG et in vivo chez la souris, le remodelage génique de nocicepteurs induit par les traitements de chimiothérapie, en corrélation avec l’apparition de neuropathies périphériques que j'ai mesurées par des tests comportementaux. Cela nous a permis d'identifier une famille de molécules candidates, qui pourraient potentiellement contrer le mécanisme identifié dans ces travaux. L'une de ces molécules permet de rétablir l’expression génique de nocicepteurs et aussi de supprimer les neuropathies périphériques chez la souris. Ce travail devrait se poursuivre dans le cadre d'un processus de valorisation, ayant pour objectif d'aboutir à un traitement préventif et/ou curatif, de ces neuropathies chez les patients. / Platinum-based drugs (cisplatin, oxaliplatin and carboplatin) and taxanes (paclitaxel and docetaxel) are among the most common drugs families used in chemotherapy. They are used for treatment of numerous human cancers including bladder, breast, head and neck, lung, ovarian, prostate and testicular cancers. However, these anticancer drugs cause significant peripheral neuropathies, that can become irreversible and leave serious clinical sequelae in patients. These include tinnitus, dizziness, tingling, numbness, loss of sensitivity, allodynia to touch or temperature changes and hyperalgesia. These side effects are highly restrictive and significantly reduce the quality of life of 30-50% of patients. The clinical significance is considerable, since it leads to about one-third of patients with stopping and/or changing treatments, although these are effective on tumors.Platinum-based drugs are DNA binding agents: they generate DNA lesions on the purine bases of DNA, that will be recognized by DNA damage response proteins, leading to cell death. Taxanes block the cell cycle in mitosis, by stabilizing the microtubule cytoskeleton against depolymerization. The fact that these two completely different antitumor mechanisms of action, induce the same peripheral neuropathies in the short to medium term, is paradoxical and has no explanation.The aim of my PhD research project was to study the mechanism(s) behind these neuropathies and to develop a new formulation to prevent and/or reduce them. Therefore, I studied the effects of taxanes and platinum-based drugs on several ion channels, involved in nociception. These ion channels, called nociceptors, are transcribed into the cell bodies of dorsal root ganglia (DRGs) and located to the peripheral nerve endings. They detect mechanical, thermal and chemical stimuli and generate or transmit the corresponding action potentials. Changes in gene expression and/or activity of nociceptors, will therefore modify the nociceptive thresholds and the transmission of different stimuli.My results allowed me to quantify, in primary cell culture of mouse DRGs and in vivo, the remodeling of ion channel expression induced by chemotherapy, in correlation with the development of peripheral neuropathies, that I measured by behavioral assessment. These results allowed us to identify a family of candidate molecules, that could potentially counteract the mechanism identified in this work. I showed that one of these molecules, can restore the gene expression of nociceptors and suppress peripheral neuropathies in mice. This work should continue as part of a valorization process, aiming to lead to a preventive and/or curative treatment, of these neuropathies in patients.

Indiana University-Purdue University Indianapolis (IUPUI) / Although paclitaxel is a commonly used anti-neoplastic agent for the treatment of solid tumors, therapy often results in a number of side effects, the most debilitating of which is peripheral neuropathy. Peripheral neuropathy is defined as a pathology of peripheral nerves, and, depending on the type of nerves damaged, the neuropathy can be classified as sensory, motor, or autonomic neuropathy. In the case of peripheral neuropathy induced by paclitaxel, the symptoms are experienced in the extremities and are sensory in nature. Patients undergoing chemotherapy with paclitaxel often report sensory disturbances such as burning, tingling, numbness, a diminished sensation to pain and temperature, loss of vibration sense, loss of proprioception, and loss of deep tendon reflexes. Electrophysiological abnormalities including decreased sensory nerve action potential amplitude and conduction confirm damage to large myelinated fibers. However, the involvement of damage to small diameter sensory neurons in the etiology of paclitaxel – induced peripheral neuropathy is still controversial. Therefore, experiments were performed to determine if paclitaxel alters the function of small diameter sensory neurons and to examine the mechanisms responsible for the change in function. vi Sensory neuron mediated vasodilatation in paclitaxel – injected animals was examined as an indirect measure of calcitonin gene related peptide (CGRP) release and therefore of sensory neuron function. CGRP release was also directly measured from central terminals in the spinal cord. To examine mechanisms of paclitaxel – induced sensory neuron damage, CGRP release and neurite length was examined in paclitaxel – treated sensory neurons in culture. The results demonstrate that (1) paclitaxel decreases the ability of small diameter sensory neurons to produce an increase in blood flow in the skin; (2) paclitaxel alters the release of CGRP from the small diameter sensory neurons; (3) paclitaxel causes the neuronal processes of isolated sensory neurons to degenerate. This dissertation provides novel information showing that paclitaxel alters the function of small diameter sensory neurons and thus provides a better understanding of the mechanisms mediating the sensory disturbances characteristic of peripheral neuropathy resulting from chemotherapy with paclitaxel.

BACKGROUND:Serum protein acidic and rich in cysteine (SPARC) is a matricellular secreted glycoprotein that performs several cellular functions and has been implicated in tumorigenesis in a variety of tumor types. The chemotherapeutic agent nanoparticle albumin-encapsulated (NAB)-paclitaxel has been postulated to exploit SPARC expression to target neoplastic cells. SPARC's role, and potentially the role of NAB-paclitaxel, in the highly heterogeneous class of soft-tissue sarcomas (STS) has not been investigated. Our objective was to explore the pattern of SPARC expression and its prognostic significance in STS.METHODS:27 tissue specimens representing various STS histologies were stained for SPARC expression by immunohistochemistry (IHC). Staining intensity was scored blindly. Survival was determined from patients' medical records and analyzed using Kaplan-Meier and log-rank with respect to SPARC expression level.RESULTS:Elevated SPARC expression was observed in 15/27 (56%) specimens. Overall patient survival segregated strongly based on levels of SPARC expression. Patients who expressed low-to-moderate levels of SPARC exhibited median survival of 22.1months, while the median survival of patients with moderate-to-high expression levels was 4.4months (log rank / p=0.0016).CONCLUSIONS:SPARC expression is elevated in a significant proportion of STS specimens analyzed in this study, but it does not appear to correlate with specific STS histologies. Given our limited sample size, we cannot draw definitive conclusions regarding association of SPARC with STS subtype. Overall survival segregates strongly by degree of SPARC expression, with elevated expression being adverse. If validated in a larger study, our results suggest that trials in STS with agents potentially targeting SPARC, such as NAB-paclitaxel, should be stratified by SPARC expression level.

published_or_final_version / Paediatrics and Adolescent Medicine / Master / Master of Philosophy