Both primary and secondary liver cancers are common and the majority of patients are not eligible for surgical resection or a liver transplant, which are considered the only hope of cure. Mortality rates are high and there is a need for alternative treatment options. New forms of local treatment work best on small tumours; large ones, however, remain difficult to treat. Hyperthermia involves heating tumours to 40??-44?? C. The aim is to heat the entire tumour without damaging the surrounding normal tissue. Treating deep seated tumours is technically challenging. Ferromagnetic embolisation hyperthermia (FEH) is a novel method of treating liver tumours. Magnetic microspheres are infused into the hepatic artery and lodge primarily in the tumour periphery. An applied alternating-current magnetic field causes the microspheres to heat. Animal experiments have shown that this is a promising technique. There is a need for modelling of FEH prior to commencement of clinical trials. Analytical and numerical models of tumour heating during FEH treatment are presented here. The models help predict the temperature distributions that are likely to arise during treatment and give insight into the factors affecting tumour and liver heating. The models incorporate temperature-dependent thermal properties and blood perfusion rates of the tissues and a heterogeneous clustering of microspheres in the tumour periphery. Simulations show that the poorly perfused tumours heat preferentially while the liver is effectively cooled by blood flow from the portal vein. A peripheral distribution of heat sources produces a more even temperature field throughout the tumour, compared to a heat source that is centred within the tumour core. Large tumours reach higher temperatures and have higher heating rates, supporting experimental findings. Using temperature-dependent, rather than constant, values for thermal conductivities and blood perfusion rates results in higher temperatures within the tumour. The uneven clustering of microspheres in the tumour periphery leads to a more heterogeneous temperature distribution in the core, but it has less of an effect on the wellperfused liver. The results show that FEH has the potential to effectively treat liver tumours and the technique merits further investigation.

Primary liver cancer (PLC) is the second most common cause of cancer death worldwide, preceded only by lung cancer. Current models for PLC either fail to fully recapitulate tumour histology and architecture or are expensive, time consuming and do not allow for personalised drug testing. During the first part of my PhD, I have collaborated with Dr. Laura Broutier in order to established a new 3D in vitro model system for liver cancer. Based on the current knowledge on organoid cultures, we have managed to establish a system to grow primary human liver cancer cells long-term (Broutier et al., in press). Interestingly, the tumour-derived organoids (tumoroids) recapitulate the original tumour histology and genetic alterations and are also able to generate tumours in an in vivo xenograft mouse model after long-term expansion. Furthermore, we have shown that tumoroids can also be successfully used for drug testing, suggesting their use to devise new targeted therapy as well as personalised treatment strategies. Current models to investigate the role of genes in cancer rely mostly on animal studies, which can be very time consuming and cost demanding, especially if resulting in negative outcomes. To overcome this issue, I have set up a protocol for introducing mutations in healthy human liver organoids using the CRISPR-Cas9 technology. Interestingly, after mutating TP53, RNF43 and ZNRF3 either alone or in combination, human organoids undergo genetic alterations and phenotypic changes that partially resemble the ones observed in tumoroids. This data suggests that this system could be used as a screening platform to study gene function before using animal models. In the last part, I have further explored the role of RNF43 and ZNRF3 (R&Z) - two newly identified WNT pathway negative regulators mutated in many cancer types - in the liver using an in vivo mouse model. Interestingly, conditional deletion of R&Z specifically in adult mouse hepatocytes results metabolic changes that eventually lead to extensive liver damage. However, when the liver is challenged to regenerate in a chronic damage model, R&Z mutated livers fail to fully repair and show presence of multiple regenerative nodules. Later, livers develop either focal nodular hyperplasia and/or early hepatocellular carcinoma. These data suggest that R&Z have an important role in both liver metabolic homeostasis and liver regeneration and that their alteration can eventually lead to cancer formation.

Orientador: Jorg Kobarg / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-05T13:22:48Z (GMT). No. of bitstreams: 1 Rui_Edmilson_D.pdf: 2734113 bytes, checksum: fe1cd8f79cba161393315108c9b5eef8 (MD5) Previous issue date: 2005 / Resumo: A hepatite B constitui um grave problema de saúde pública. Dados epidemiológicos estimam que aproximadamente 350 milhões de pessoas são portadores do vírus da hepatite B (HBV). Admite-se que a infecção evolui para a cura em média 95% dos casos, entretanto nos portadores crônicos a infecção pode evoluir para cirrose e carcinoma hepatocelular (HCC). Há um crescente acúmulo de evidências que relaciona a proteína HBx do HBV ao desenvolvimento do HCC. A maioria dos estudos sobre a função da proteína HBx sugere que ela é uma proteína reguladora de funções pleiotrópicas com a capacidade de induzir o crescimento tumoral. Isso é possivelmente devido à sua capacidade de interagir com uma vasta gama de proteínas celulares. No presente estudo investigamos os aspectos moleculares da estrutura e função da proteína HBx e os resultados foram contextualizados no processo de transformação celular. Observamos pela primeira vez a capacidade da proteína HBx em se ligar ao RNA contendo seqüências ricas em adenina e uracila (AU), que são presentes em alguns proto-oncogenes como c-myc e c-fos. A geração de proteínas truncadas permitiu mapear a região de interação entre HBx e RNA. Realizamos ensaios de mutação sítio-dirigida em HBx e substituímos todas as cisteínas por serinas. Nossos resultados sugerem que as cisteínas na proteína HBx são de menor importância para a sua interação com o RNA e com as proteínas humanas p53 e RXR. Descobrimos ainda uma nova proteína humana que interage com HBx: E4F. Este fator de transcrição humano está relacionado com o controle do ciclo celular, com a segregação cromossômica e com a embriogênese. Ensaios em leveduras e in vitro mostraram que HBx selvagem, bem como as suas formas mutadas, foram capazes de interagir e regular a função de E4F, indicando um possível novo mecanismo para a transformação celular e a regulação da transcrição viral, uma vez que E4F exibiu uma capacidade de interagir com a região ¿enhancer II¿ do genoma do HBV / Abstract: Viral hepatitis is an important global public health problem. Epidemiological data show that worldwide 350 million people are chronically infected with the hepatitis B virus. About 95% of the infections cure spontaneously, but the chronically infected patients may develop liver cirrhosis or even hepatocellular carcinoma (HCC). A large body of evidence points to the viral onco-protein HBx as the principal cause for the cellular transformation. The majority of studies on HBx function suggest that it is a regulatory protein with pleiotropic functions and its capacity to induce tumor growth may be due to its ability to interact with a diverse array of cellular proteins. In the present study we investigated molecular and structural aspects of the function of the HBx protein in order to be able to shed light on the process of cellular transformation. We were able to demonstrate that HBx protein has the ability to bind to an AU-rich RNA sequences present in the mRNAs of certain proto-oncogenes such as c-myc and c-fos. The generation of truncated proteins allowed to map the region of interaction of HBx with the RNA. Furthermore, we performed site directed mutagenesis studies of HBx protein and substituted all of its cysteine residues with serines. Our data suggest that the cysteine residues in the HBx protein are of minor importance for its interaction with RNA, p53 and RXR proteins. Finally, we discovered in E4F a new human interacting protein partner for the HBx protein. The transcription factor E4F has been functionally implicated in the control of the cell cycle, the chromosomal segregation and embriogenesis. In studies using the yeast we further showed that wild-type HBx, as well as its mutated forms, can physically interact with the E4F protein and regulate its function. This indicates a possible new mechanism of cellular transformation and the regulation of the viral transcription, since the human protein E4F demonstrated the capacity to bind to the enhancer II region of the HBV genome / Doutorado / Bioquimica / Doutor em Biologia Funcional e Molecular

The incidence of cancer worldwide has increased over the years, and gastrointestinal cancers (G.I.) are amongst the most common forms of cancer. Nevertheless, there is still no curative treatments for this group of tumors. Nucleoside analogues are widely used in cancer treatment. The prevailing compounds are Gemcitabine (used for pancreatic cancer and other carcinomas), 5-Fluorouracil (used in breast, colon, and other cancers), Cytarabine and Clofarabine (used in leukemias). Gemcitabine, the current standard of care for various forms of solid tumors, has a limited efficacy against pancreatic cancer. The objective of this project was the development of effective drugs against pancreatic cancer. We focused on a novel class of nucleoside analogues designed to bypass the most common cellular road blocks and resistance mechanisms. After an extensive screen for cell killing activity, two lead molecules were exclusively studied: LCB2151 and LCB2132. These two molecules showed high efficacy in killing human cancer cells from three different human G.I. cell lines: BxPC3 and Capan-2, two pancreatic cell lines representative of K-Ras positive and negative tumors, as well as the liver cell line HepG2. LCB2151 showed high efficacy in killing Gemcitabine-resistant cancer cells, and a low toxicity in normal cells. Interestingly, results show that these prodrugs can efficiently bypass key resistance mechanisms developed by cancer cells. The results obtained in this project are promising and could pave the way for a more effective treatment of pancreatic cancer.

>Magister Scientiae - MSc / Nanoscience is the study of phenomena and objects at the nanoscale (around 1-100 nm), socalled nanomaterials. These nanomaterials exhibit novel properties that are often very different to those of the bulk materials used for their synthesis. Hence, nanoparticles are widely commercialised, especially silver nanoparticles (AgNPs) due to their antimicrobial properties and some other useful phenomena. This commercialisation leads to inevitable exposure to the environment and humans, which leads to inhalation, ingestion or dermal uptake of AgNPs by the human body culminating in distribution to several major organs, including the liver. Both chronic and acute exposure to AgNPs have been linked to detrimental effects in both in vitro and in vivo studies. These include oxidative stress, induction of inflammation, DNA damage, cell death and many others.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23409号 / 医博第4754号 / 新制||医||1052(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 妹尾 浩, 教授 武藤 学, 教授 小川 誠司 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18156号 / 医博第3876号 / 新制||医||1003(附属図書館) / 31014 / 京都大学大学院医学研究科医学専攻 / (主査)教授 野田 亮, 教授 武藤 学, 教授 小川 誠司 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20073号 / 医博第4166号 / 新制||医||1018(附属図書館) / 33189 / 京都大学大学院医学研究科医学専攻 / (主査)教授 高田 穣, 教授 武藤 学, 教授 武田 俊一 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20249号 / 医博第4208号 / 新制||医||1020(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 清水 章, 教授 松田 道行, 教授 武田 俊一 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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