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No description available.

No description available.

No description available.

Submitted in partial fulfillment of the requirements for the degree of Doctor of Technology: Clinical Technology, Durban Institute of Technology, 2005. / Fumonisin B1 (FB1) and ochratoxin A (OTA) represent examples of mycotoxins of greatest public health and agro-economic significance. They exert adverse effects on humans, animals and crops that result in illnesses and economic losses. Fumonisin B1 are cancerpromoting metabolites of Fusarium proliferatum and F verticillioides, (formerly moniliforme), and are implicated in oesophageal cancer. Ochratoxins are metabolites of both Aspergillus and Penicillium species. These compounds are known for their nephrotoxic effects in all animal species and may promote tumours in humans. In man OTA exhibits unusual toxicokinetics, with a half-life in blood of 840 h (35 days) after oral ingestion. Although much is known regarding the toxicology of these toxins, little is known of the effects of these toxins on the immune system. The aim of this study was to determine and compare the immunornodulating effects of FB1 and OTA in human carcinoma. Initial experiments involved isolating lymphocytes and neutrophils from healthy volunteers. The isolated cells were exposed to either FB1 or OTA on a dose and time dependent level and LD50 of the toxins was determined. Thereafter, challenge tests were performed, whereby lymphocytes and neutrophils isolated from volunteers, oesophageal cancer patients and breast cancer patients were exposed to the LD50 dose of either FB1 or OTA for the appropriate time. The effect of the toxins was demonstrated by viability studies, light microscopy and electron microscopy. Cytokine receptors (CK, TNF and CSF) were evaluated by immuno-cytochemical methods and the levels of circulating cytokines (IL -1, IL-6, IL-8, IL-10 and TNF-a) were determined using ELISA kits. / D

The cytochromes P450 (CYPs), epoxide hydrolases (EHs) and glutathione S-transferases (GSTs) are three of the major families of enzymes involved in the metabolism of xenobiotics in the human body. Immunohistochemical analysis revealed a high frequency of expression of xenobiotic metabolising enzymes in all tumour types studied, in contrast to corresponding normal tissue which displayed only low levels of expression. Further examination of the CYP1 family was carried out by immunoblot analysis. All breast tumours studied were found to express CYP1B1, and not CYP1A1 or CYP1A2. Moreover, CYP1B1 was identified in a number of kidney tumours but not in corresponding normal kidney, indicating that CYP1B1 may be a tumour-specific form of CYP, RT-PCR, in combination with restriction digestion and DNA sequencing, was used to identify CYP mRNA species present in several tumour types. Although CYP1A1 mRNA was identified in breast carcinomas, CYP1B1 was found to be the most frequently expressed form of the CYP1 family in this tissue. CYP3A mRNA was also displayed by several breast tumours, and demonstrated by sequencing to be CYP3A5. A similar situation to breast tumours was observed in tumours of the gastro-intestinal and urinary tracts, with CYP1B1 being the most frequently expressed form of the CYP1 family, and only a small number of samples displaying evidence of CYP1A mRNA. The effects of the expression of xenobiotic metabolising enzymes in tumours may be complex, and depend upon the relative amounts of active protein present, but it is likely that they will exert an influence on both the development of carcinogenesis and the anti-cancer drug resistance of tumours.

Exposure to ionising radiation increases the risk of cancer, including acute myeloid leukemia (AML), which is the most common myeloid leukaemia. The C-terminal binding protein (CtBP)-interacting protein (CtIP), which is essential for embryonic development and possibly functions as a tumour suppressor, has been identified as a strong candidate for susceptibility to radiation-induced AML (rAML).

El presente trabajo es un estudio correlacional de tipo retrospectivo, de casos y controles, siendo 39 pacientes con cáncer colorrectal del tipo histológico mucinoso los que conforman el grupo de los casos y dos grupos de 117 pacientes cado uno, el primero de pacientes con cáncer colorrectal de otro tipo histológico y el segundo de pacientes con patología digestiva benigna, que conforman los controles; coleccionados entre los años 2002 y 2008 en el Hospital Nacional Edgardo Rebagliati Martins. Se determinó la asociación de los factores de riesgo como: la edad, el género, de riesgo el consumo de tabaco, el consumo de alcohol, la irradiación pélvica, la colecistectomía, el tipo de dieta, la obesidad, otros tipos de cáncer previos, la raza, algunas características clínicopatológicas tales como: la localización del tumor, el grado de diferenciación, el estadio de la enfermedad al momento del diagnóstico y la respuesta al tratamiento recibido; y el cáncer colorrrectal de tipo histológico mucinoso. Al analizar las varaibles mencionadoas se determino que la edad cada vez mayor es una factor de riesgo asociado con mayor probabilidad de cáncer no mucinoso, en tanto la variable obesidad es un factor asociado con mayor probabilidad al cáncer mucinoso. En cuanto a la localización del tumor existe asociación entre el cáncer colorrectal de tipo histológico mucinoso y la localización proximal del colon. El grado de diferenciación moderado y el estadio IIA se encontraron con más frecuencia en este estudio. La sobrevida para los tumores de tipo mucinoso es menor que para los otros tipos histológicos a pesar que la diferencia no llegue a ser significativa.

Les kallicréines tissulaires humaines (KLK) ont récemment émergé comme une famille de protéases à serine pouvant jouer un rôle important dans la tumorigenèse. Le but de cette étude a été de mieux comprendre comment KLK6 et KLK12 pourraient intervenir dans la physiopathologie pulmonaire. Nous avons démontré qu’une expression ectopique de KLK6 induisait la prolifération des cellules A549 d’une manière dépendante de son activité enzymatique, une résistance à l’apoptose, ainsi qu’une translocation nucléaire de la β-caténine. Nous avons également montré une voie de signalisation impliquée dans la prolifération induite par KLK6 impliquant PAR2, EGFR et ERK. Nous avons identifié de nouveaux subtrats pour KLK12 : les CCN. Nous avons démontré que le clivage de CCN1 et CCN5 par KLK12 limitait leurs fixations avec le VEGF, BMP2 et le TGF-β1. / Recently, human tissue kallikreins (KLK) emerged as a new family of serine proteases which might play a major role in the tumorigenesis. The project aims at determining the contribution of KLK6 and 12 in lung pathophysiology. We showed that ectopic KLK6 promoted A549 cell proliferation in a protease activity-dependant manner, inhibited cell apoptosis and induced β-catenin nuclear translocation. Furthermore, this study uncovered a signaling pathway mediated by KLK6 in promoting A549 cell proliferation trough activation of the PAR2-EGFR-ERK pathway.We have also identified novel substrates of KLK12, the CCN family. We reported that KLK12-mediated proteolysis of CCN1 and CCN5 can reduce or abolish the binding of VEGF, BMP2, and TGF-β1.

L’analyse protéomique est une méthode de choix pour la recherche de biomarqueurs. Sans à priori, elle permet d’établir un catalogue de protéines qui sont exprimées dans une cellule, un tissu ou un organisme entier. Cette approche a été mise en œuvre pour une analyse protéomique de cellules coliques cancéreuses et une analyse phosphoprotéomique de biopsies hépatiques.L’étude de cellules coliques cancéreuses transformées par le gène cytosine désaminase et traitées par la prodrogue 5-fluorocytosine a été réalisée par électrophorèse bidimensionnelle des extraits protéiques. L’analyse d’image a permis la quantification de 353 protéines et isoformes dont 14 sont surexprimées et 4 sous exprimées lors d’un traitement par la prodrogue. Parmi les protéines dont l’expression est affectée par le traitement, l’HSP90 présente un niveau d’expression constant mais est identifiée sous deux formes qui diffèrent par leur pI. L’analyse par spectrométrie de masse à identifier une phosphorylation de ser 254 qui pourrait contribuer à la régression tumorale.Après avoir développé une méthode HPLC-TiO2 pour la purification de phosphopeptides, une analyse protéomique de 24 biopsies humaines provenant de carcinomes hépatocellulaires sur foie non fibreux (nf-CHC) et de tissus sains a été réalisée avec la technologie iTRAQ. Les peptides surexprimés dans les tumeurs correspondent à des protéines de choc thermiques, des protéines liées à l’ADN/ARN (histones, protéines du splicéosome), des protéines de la phase 1 de la détoxification (carboxyestérase, époxide hydrolase), les protéines du cytosquelette (actinine, tubuline), des protéines ou enzymes anti-oxydantes (superoxide dismutase, thiorédoxine). Les peptides sous-exprimés correspondent à des protéines du cycle de l’urée, de la détoxification (alcool déhydrogénase) du métabolisme des sucres, des lipides et des acides aminés. Dans la fraction TiO2, 19 phosphopeptides sont significativement surexprimés et 15 phosphopeptides sont significativement sous exprimés, mettant en en évidence une surreprésentation du motif –(S/T)P- parmi les phosphopeptides surexprimés dans les tumeurs. Une activation des proline directed kinases ou une inhibition des phosphatases correspondantes est donc probablement un événement caractéristique des nf-CHC. Ces peptides/protéines dérégulées sont autant de biomarqueurs potentiels pour le carcinome hépatocellulaire. / Proteomic is a method of choice for biomarker research, without a priori, it establishes a directory of proteins that are expressed in a cell, tissue or an entire organism. This approach has been implemented for proteomic analysis of colon cancer cells and phosphoproteomic analysis of liver biopsies.The study of colon cancer cells transformed by the cytosine deaminase and treated with the prodrug 5-fluorocytosine was performed by two-dimensional electrophoresis. Image analysis allowed the quantification of 353 proteins, 14 isoforms are overexpressed and 4 under expressed during treatment with the prodrug. Among the proteins whose expression is affected by the treatment, HSP90 has a constant level of expression, but is identified in two isoforms that differ in their pI. Mass spectrometry identified phosphorylation of ser 254 which could contribute to tumour regression.After developed an HPLC- TiO2 method for the purification of phosphopeptides, a proteomic analysis of 24 biopsies from human hepatocellular carcinoma on non-fibrous liver (nfCHC) and normal tissue was performed with the iTRAQ technology. Peptides overexpressed in tumours correspond to HSPs, DNA / RNA binding proteins (histones, spliceosome), proteins form Phase 1 detoxification (carboxyesterase, epoxide hydrolase), the cytoskeletal proteins (actinin, tubulin), antioxidant proteins or enzymes (superoxide dismutase, thioredoxin). The under-expressed peptides belong to proteins of the urea cycle, the detoxification (alcohol dehydrogenase) metabolism of sugars, lipids and amino acids. In the TiO2 fraction, 19 phosphopeptides are significantly overexpressed and 15 phosphopeptides were significantly under-expressed. This phosphoproteome has demonstrated an overrepresentation of the (S/T)P pattern among overexpressed phosphopeptides, indicating activation of proline-directed kinases in nfCHC or inhibition of the corresponding phosphatases. These deregulated peptides/proteins are as potential biomarkers for hepatocellular carcinoma.