O carcinoma epidermoide de cabeça e pescoço (HNSCC) é uma das neoplasias mais frequentes e geralmente está associado a inflamação crônica e níveis sistêmicos de citoquinas. Seus principais fatores de risco são a exposição ao tabaco e álcool. Publicações recentes sugerem que a infecção por papiloma vírus HPV está relacionada com a tumorigênese de cabeça e pescoço e pode alterar o perfil e o desfecho deste tumor. A transição epitelial-mesenquimática (EMT) é um processo importante durante a tumorigênese pelo qual células epiteliais obtêm um fenótipo migratório e invasivo. Os efeitos da infecção por HPV e de citocinas inflamatórias neste processo ainda não são bem compreendidos em HNSCC. O presente estudo teve como objetivo transfectar células normais e neoplásicas com os genes E6/E7 de HPV16 e investigar os mecanismos pelos quais a EMT é ativada por citocinas inflamatórias e por infecção por HPV. Taxas de proliferação, viabilidade, migração e invasão celular induzidas por IL-6, TNF-a e TGF-beta foram avaliadas em linhagens celulares derivadas de queratinócitos normais e de carcinoma de língua (HaCat e SCC25, respectivamente) transfectadas com os genes E6/E7 de HPV16 e a expressão dos marcadores relacionados a EMT foram analisados por PCR em tempo real nas linhagens SCC25, HaCat e FaDu (carcinoma de faringe). Os resultados sugerem que o HPV modificou a morfologia das linhagens normal e tumoral. Na linhagem HaCat, o ambiente inflamatório estimulou modificações importantes para o desenvolvimento de condições patológicas. A inserção dos genes E6/E7 de HPV16 diminuiu a proliferação e a viabilidade na linhagem HaCat e o ambiente inflamatório não modificou a resposta iniciada pelo HPV. Na linhagem SCC25 a inserção de HPV em associação com inflamação reduziu a progressão da EMT, ao contrário do que foi observado na linhagem FaDu. A relação de HPV com inflamação levando a progressão de EMT é controversa e dependente do sítio anatômico em tumores de cabeça e pescoço / Head and neck squamous cell carcinoma (HNSCC) is one of the most frequent neoplasias and is often associated with chronic inflammation and systemic cytokine levels. Its main risk factors are tobacco and alcohol exposition. Recent publications suggest that the infection by human papillomavirus (HPV), especially high-risk types, is related to head and neck tumorigenesis and may alter the tumor profile and outcome. Epithelial-mesenchymal transition (EMT) is an important process during tumorigenesis by which epithelial cells gain a migratory and invasive phenotype. The effects of HPV infection and inflammatory cytokines on this process are still not well understood in HNSCC. The present study aimed to transfect normal and neoplastic cells with E6/E7 genes of HPV type 16, and to investigate the mechanisms by which EMT is activated by inflammatory cytokines and by HPV infection. Proliferation, viability, migration and cell invasion rates induced by IL-6, TNF-a and TGF-beta cytokines will be also evaluated in cell lines derived from normal keratinocyte and tongue carcinoma (HaCat and SCC25, respectively) transfected with HPV16 E6/E7 genes and the expression of the EMT-related markers were analyzed by real-time PCR in the SCC25, HaCat and FaDu (pharyngeal carcinoma). The results suggest that HPV modified the morphology of normal and tumor cell lines. In the HaCat cell line, the inflammatory environment stimulated important modifications for the development of pathological conditions. Insertion of HPV16 E6/E7 genes decreased proliferation and viability in the HaCat and the inflammatory environment did not modify the HPV-initiated response. In the SCC25 cell line the insertion of HPV in association with inflammation reduced the progression of EMT, unlike was observed in FaDu. The relationship of HPV with inflammation leading to progression of EMT is controversial and depends on anatomical site in head and neck carcinoma

Sabemos hoje que os tumores sólidos apresentam uma composição celular heterogênia e que apenas uma pequena parcela dessas células apresenta capacidade de se proliferar e gerar novos tumores. Estudos prévios sobre a formação do câncer de mama têm sido realizados com base na combinação dos marcadores de superfície celular CD44 e CD24. Já foi demonstrado que uma subpopulação de células do câncer de mama com alta expressão de CD44 e baixa expressão de CD24 (CD44+/CD24-) tem maior capacidade de gerar tumores, quando comparadas com a subpopulação de células CD44-/CD24+. O objetivo do estudo foi identificar a taxa de células com fenótipo CD44+/CD24- presentes nos tumores mamários e relaciona-la com a taxa de comprometimento dos linfonodos axilares ipsilaterais por neoplasia, além de avaliar também sua relação com outros fatores sabidamente relacionados com mal prognóstico da paciente. Pacientes e métodos: avaliamos prospectivamente 53 amostras cirúrgicas provenientes de 42 pacientes com diagnóstico histopatológico de carcinoma de mama, quantificando as células CD44+/CD24- por citometria de fluxo. Relacionamos a porcentagem destas células encontrada em cada amostra com o comprometimento axilar, os receptores hormonais e Her-2, a idade da paciente, o grau histológico do tumor, o diâmetro patológico do tumor e o tipo histológico. Resultados: verificamos um significante aumento da população de células CD44+/CD24- no grupo de carcinomas ductais invasivos em pacientes que apresentavam metástase axilar [mediana 8,53% (3,6 71,2%)] em relação ao grupo de pacientes sem linfonodos comprometidos pela neoplasia [mediana 1,49% (0,3 17,1%)] (p=0,0002). Conclusão: concluímos então que quando estudamos vários tumores mamários invasivos de mesma classificação histológica, podemos notar que existe uma variação na quantidade de células CD44+/CD24- entre eles. Nosso estudo mostrou que essa variação está relacionada à agressividade tumoral e à sua capacidade de gerar metástases já que, tumores com maior quantidade de células CD44+/CD24- apresentam maior taxa de comprometimento dos linfonodos axilares. / It is known that solid tumors are composed by a heterogeneous combination of cells and only a small portion of these cells has the capacity to proliferate and generate new tumors. Previous studies about the breast cancer initiation have been based on a combination of CD44 and CD24cell surface markers. It has been shown that this subpopulation of breast cancer cells with high expression of CD44 and low expression of CD24 (CD44+/CD24-) has a greater capacity to generate tumors when compared with the subpopulation of cells CD44- /CD24+. The study objective was to identify whether the rate of cells with CD44+/CD24- phenotype present in breast tumors is related with the rate of ipsilateral lymph node metastasis, in addition to evaluate its relationship with other risk factors known to be related with worst prognosis. Patients and methods: we prospectively evaluated 53 surgical specimens from 42 patients with histological diagnosis of breast cancer, quantifying CD44+/CD24- cells through flow cytometry. We list the percentage of these cells found in each sample with axillary lymph node status, hormone receptors and Her-2, patient age, histological grade, pathological tumor diameter and histological tumorclassification. Results: we find a significant increase of CD44+/CD24- population in the invasive ductal carcinomas, in patients with axillary metastasis [median 8.53% (3.6 - 71.2%)] than in the group of patients without lymph nodes metastasis [median 1.49% (0.3 - 17.1%)] (p = 0.0002). Conclusion: when we studied several invasive breast tumors of same histological classification, we note that there is variation in the number of CD44+/CD24- cells. Our study showed that this variation is related to tumor aggressiveness and their ability to generate metastasis, because tumors with high rate of CD44+/CD24- cells have a higher rate of lymph node metastasis.

A terapia fotodinâmica (TFD) é uma técnica não invasiva usada no tratamento de lesões de pele, como câncer basocelular, queratose actínica, e doença de Bowen, dentre outros. Basicamente, a combinação da administração de um fotossensibilizador (FS), com a irradiação de luz adequada e o oxigênio celular, gera uma série de reações oxidativas que provocam a morte do tecido. Contudo, o principal efeito colateral desta terapia é a fotossensibilidade prolongada ocasionada pela administração de fotossensibilizadores sistêmicos. Por outro lado, a via tópica não apresenta esta limitação, pois o tratamento é realizado no local da lesão através de pró-drogas. O ácido aminolevulínico, ALA, está entre as pró-drogas mais utilizadas para indução do acúmulo do agente fotossensível na pele, a protoporfirina IX, ou PpIX. Contudo, a via tópica não permite penetração suficiente e homogênea do creme para o tratamento de lesões espessas. Visando a melhoria da TFD, foram realizados estudos in vivo e in vitro. Nos estudos in vivo, técnicas mecânicas - rolos de microagulhas, tape stripping e injeção livre de agulhas foram estudadas buscando encontrar a mais eficiente nos quesitos de: promoção da penetração da pró-droga no tecido, distribuição homogênea e de indução do acúmulo de PpIX. Para isto, foi o utilizado o modelo porcino, in vivo, conhecido como o modelo que possui a pele mais similar à pele humana. Os resultados in vivo mostram que as técnicas têm resultados similares na produção de PpIX e na distribuição de porfirina mais homogênea na superfície. Além disso, todas as técnicas estudadas in vivo têm se destacado em promover uma entrega mais homogênea de ALA também na profundidade da pele quando comparadas ao grupo controle. Nos estudos in vitro, foram examinadas possíveis diferenças na capacidade de formação da PpIX e/ou de resistência de células ao tratamento por TFD entre células expressando diferentes características de transição epitélio-mesenquimal. Os resultados in vitro indicam que as células com características epitélio-mesenquimal mais acentuadas produzem mais PpIX e são mais responsivas à TFD. Estes resultados indicam que a TFD tem maior efetividade no tratamento de células mesenquimais, e os estudos in vivo mostram que no tecido normal há maior seletividade de produção na camada da epiderme e apêndices da pele sugerindo que a terapia pode ser utilizada com maior eficiência em lesões superficiais e, até mesmo diminuir as taxas de recorrência devido a heterogeneidade de distribuição do creme na pele quando umas das técnicas mecânicas são utilizadas. / Photodynamic therapy (PDT) is a noninvasive technique used to treat skin lesions, such as basal cell cancer, actinic keratosis and Bowen\'s disease. Basically, the administration of a photosensitizer (PS), combined with the illumination of adequate light and the cellular oxygen, generate a series of oxidative reactions that cause tissue death. However, the major side effect of the treatment is prolonged photosensitivity caused by the systemic administration of photosensitizers. On the other hand, the topical therapy does not show this limitation, and it is performed at the lesion site via prodrugs. The aminolevulinic acid, ALA, is the most popular pro-drug in topical PDT. This prodrug induces PpIX production that is a photosensitive porphyrin. However, when ALA is used topically, the cream does not provide enough or homogeneous penetration for the treatment of deep lesions. Therefore, with the aim of improving PDT therapy, studies in vivo and in vitro were performed. In the in vivo analysis, mechanical techniques - microneedle roller, tape stripping, and needle-free injection- were studied looking for the most effective regarding to improve the following purposes: promoting penetration of the prodrug into the tissue, homogeneous distribution, and at inducing PpIX accumulation. The evaluations were made by fluorescence spectroscopy, biopsy of skin, and fluorescence images, using the porcine model, in vivo, known as the most similar of human skin tissue. The in vivo results showed that all techniques have similar results in the production of PpIX, and perform a more homogeneous porphyrin distribution in the skin surface. Moreover, all the techniques have excelled in promoting a homogeneous distribution of PpIX in the deep of the skin when compared to the control group. In addition to the skin penetration, studies of PpIX production were performed in vitro in cells expressing different levels of epithelial-mesenchymal transition characteristics. The studies were made in regard to a possible difference in PpIX formation capacity and / or a resistance to the PDT treatment. The in vitro results showed that cells with more epithelial-mesenchymal characteristics produce more PpIX and are more responsive to the PDT therapy. These results indicate that PDT therapy may have a better effectiveness in the treatment of mesenchymal cells and also the results in vivo showed that the ALA-induced PpIX in normal tissue seems to be selective to epidermal and skin appendages, indicating that the topical therapy may be used with a higher efficiency in superficial injuries providing lower recurrence rates when they combine with one of the techniques studied.

Colorectal cancer (CRC), with an estimated 1.2 million new cases annually, is the third leading cause of cancer incidence and death worldwide. Generally, the majority of CRC patients are diagnosed at the advanced stages with poor prognosis and unfavorable response to multiple therapeutic drugs. In spite of increasing knowledge of the molecular mechanism for the tumorigenesis in CRC patients, the translation from basic science into clinical therapy has been limited for quite a long time. In order to develop novel treatment strategies against CRC, intensive and extensive attempts have been made in the past decades. / The epithelial to mesenchymal transition (EMT) is a multi-step process characterized by the loss of cell polarity, decreased cell-cell adhesion as well as enhanced migration and invasion capacity. It is well documented that EMT is essential for a variety of cellular biological events ranging from embryogenesis to tumor progression. The field of lncRNA is developing rapidly and currently it is one of the most intensively studied fields in the biomedical sciences. Emerging evidence indicates that the majority of human genome encodes thousands of non-protein-coding RNA transcripts, nevertheless, the function of long non-coding RNAs (lncRNAs) in orchestrating EMT progression remains elusive. Historically, the lncRNA H19 was the first identified imprinted non-coding RNA transcript in human, and the H19/IGF2 locus acted as an ideal paradigm for the investigation of genomic imprinting genes. In recent years, the expression profiling and functional characterization of the H19 gene in a variety of human diseases has been extensively studied. / In our studies, H19 was characterized as a novel regulator of EMT in colon cancer. We first observed significant mesenchymal characteristics in the methotrexate-resistant HT-29 cells. Interestingly, significant upregulation of H19 was observed in mesenchymal-like MTX resistant HT-29 cells. We subsequently demonstrated that after treatment of TGF-β1, one of the most widely used EMT inducers, H19 presented dramatic increase during the EMT progression. To further investigate the functional role of H19 in EMT, we generated the stable cell lines overexpressing H19 in colon cancer cells using retroviral infection. Stable overexpression of H19 significantly promoted EMT progression in two epithelial colon cancer cell lines HT-29 and HCT-116. However, overexpression of H19 did not affect cell proliferation as well as cell cycle progression. Further proteomics studies screened out that ectopic expression of H19 upregulated the protein level of Vimentin, a vital biomarker for mesenchymal cells. By using the bioinformatics study in combination with luciferase reporter assays, we demonstrated that H19 potentiated the expression of several core marker genes essential for mesenchymal cells by serving as a competing endogenous RNA(ceRNA), which builds up the missing link between the regulatory miRNA network and EMT progression. According to the results from xenograft tumor model and soft agar assay, stable expression of H19 reinforced the in vitro and in vivo tumor growth. Moreover, the investigation of clinical specimens verified that H19 RNA level was significantly increased in colon cancer tissues compared with corresponding adjacent normal tissues. Taken together, the above observations imply that the lncRNA H19, by acting as a competing endogenous RNA, is an important regulator which tightly modulated the expression of multiple important genes involved in EMT and it could probably serve as a novel therapeutic target against colon cancer. / 大腸癌每年有一百二十萬新增個案，是世界第三大癌症殺手。通常情況下，大部分大腸癌病人發現時已經處於晚期，該時期的癌症病人對多種臨床治療藥物已無法治愈。盡管關於大腸癌發病的分子生物學機制已經不斷完善，但如何從基礎研究轉化為臨床治療手段在很長一段時間內不可實現。為了進一步研究新的抗擊大腸癌治療手段，廣泛且深入的研究已經不斷開展。 / 上皮間充質轉化是一個多步驟的過程，該過程的典型特徵為失去細胞的極性，細胞間粘連減弱以及細胞爬行遷移能力的不斷加強。目前科學家已經知道上皮間充質轉化對於從胚胎發育到腫瘤發展都起著重要的作用。近年來，長非編碼RNA的研究不斷快速發展，已然成為醫學研究中最激烈的領域之一。眾多證據表明人體基因組編碼數以千計不編碼蛋白質的RNA轉錄體。然而，這些RNA轉錄體在上皮間充質轉化中的功能依然所知甚少。長非編碼RNA H19是人體內第一個被鑒別出來參與到基因印記的非編碼RNA。資料表明H19/IGF2位點是一個非常理想的研究基因印記的位點。近年來，H19在眾多癌症中的表達以及功能學研究已不斷湧現，同時也不斷取得令人鼓舞的研究成果。 / 在我們的研究中，H19被鑒定為大腸癌裏上皮間充質轉化過程中一個重要的參與者。通過研究甲氨蝶呤耐藥大腸癌HT-29細胞株，我們發現該HT-29耐藥細胞株有著顯著的間充質細胞特性。有趣的是，H19在該細胞株中有著顯著升高。我們隨後用經典的上皮間充質轉化誘導劑TGF-β1處理兩株大腸癌細胞，處理後H19亦有著顯著升高。為了進一步研究H19在上皮間充質轉化，通過使用逆轉錄病毒，我們建立H19的穩定表達細胞株。穩定表達H19顯著地促進了HT-29以及SW620大腸癌細胞株的上皮間充質轉化。然後，高水平表達(過表達)H19並不影響細胞的生長以及細胞周期的進程。進一步的蛋白質組學研究表明，過表達H19能促進間充質細胞一個重要標記基因Vimentin的表達。通過生物信息學以及熒光素酶報告基因實驗，我們證明了H19通過其競爭內源性RNA的作用，能夠促進間充質細胞所需的幾個重要基因的表達。該發現建立起了miRNA網絡以及上皮間充質轉化進程的交流網絡。通過異位移植以及軟瓊脂實驗，我們發現過表達H19能夠促進腫瘤細胞的生長。而在臨床大腸癌病人組織中，我們更發現H19在大腸癌病人組織中高表達。綜上所述，我們的結果證明H19這一長非編碼RNA，能夠通過其競爭內源性RNA的作用機制，從而調控上皮間充質轉化過程中的關鍵基因。同時H19亦有可能成為治療大腸癌的臨床新靶點。 / Liang, Weicheng. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 95-124). / Abstracts also in Chinese. / Title from PDF title page (viewed on 24, October, 2016). / Liang, Weicheng.

L’invasion cellulaire est un phénomène clé du développement tumoral au cours duquel les cellules réalisent une transition épithélio-mésenchymateuse (TEM) caractérisée par des changements d’expression de gènes clés dans la régulation de l’adhérence et de la morphologie cellulaire. L’expression de ces gènes est sous le contrôle de voies de signalisation, qui lors du processus de tumorigenèse sont dérégulées. La dérégulation de ces voies est multifactorielle et peut-être initiée par une activation de récepteurs présents à la membrane plasmique.Dans ce contexte, nous avons mis en évidence que les flotillines sont d’importants régulateurs de l’activation de ces récepteurs et des voies de signalisation en aval qui conduisent à l’induction de la TEM. Les flotillines 1 et 2 sont des protéines ubiquitaires très conservées. Le niveau d’expression des flotillines est accru dans de nombreux cancers invasifs et ceci est un facteur de mauvais pronostic. En condition physiologique, non surexprimées, les flotillines sont majoritairement à la membrane plasmique. Surexprimées les flotillines induisent la formation d’endolysosomes ayant une faible activité de dégradation, dans lesquels elles sont retrouvées.Mes travaux montrent que l’augmentation de l’expression des flotillines dans des cellules normales mammaires est suffisante pour induire le processus de TEM, processus clé de l’invasion tumorale. De plus nous montrons que la surexpression des flotillines génère une voie de trafic vésiculaire que nous nommons UFIT (Upregulated flotillin Induced Trafficking pathway) et qui affecte le trafic de plusieurs récepteurs membranaires connus pour participer à l’activation des voies oncogéniques inductrices de la TEM. Dans le cas particulier d’un de ces récepteurs, AXL, cible thérapeutique dans les cancers du sein, nous montrons que la surexpression des flotillines régule son endocytose et l’adresse dans les endosomes de signalisation riches en flotillines tout en le protégeant de la dégradation. Ces travaux apportent donc des explications nouvelles quant au rôle des flotillines dans le processus d’invasion cellulaire conduisant à la formation des métastases. / Tumor cell invasion and consecutive metastasis formation are the main cause of death in cancer patients. One crucial process of tumor cell invasion is the epithelial to mesenchymal transition (EMT), a reversible process during which polarized epithelial cells convert into motile mesenchymal cells. This process is characterized by gene expression changes involved, in particular, in the perturbation of cell adhesion, polarity and cytoskeletal structures.Flotillin 1 and 2 are two ubiquitous and highly conserved membrane proteins that assemble in large oligomers, known to participate in membrane protein clustering and endocytosis. Flotillins are upregulated in many invasive cancers and are considered as markers of poor prognosis. At physiological expression level, flotillins are mainly located at the plasma membrane. The cellular distribution of upregulated flotillins is dramatically modified with a strong enrichment in vesicular compartments that we characterized as non-degradative-endolysosomes.During my PhD project, we identified that flotillins are key EMT inducer. We upregulated flotillins in normal mammary cells and demonstrated that it is sufficient to promote EMT. Using several global comparative analyses (transcriptomic, phosphokinase arrays), we showed that flotillin upregulation activates key oncogenic signaling pathways and plasma membrane receptors. We identified that flotillin overexpression induces a trafficking pathway that we named UFIT-pathway (Upregulated flotillin Induced Trafficking pathway), which promotes the endocytosis of several cargos, amongst them membrane receptors involved in the activation of oncogenic pathways.Our results suggest that the UFIT pathway generates flotillin-positive endolysosomes acting as as “signalosome compartments” involved in the activation of signaling pathways stimulating EMT and cellular invasion.

上皮間充質轉化（EMT），作為重要的生理和病理事件，廣泛的參與胚胎發育、組織纖維化病變及腫瘤轉移的過程。這一顯著的細胞表型變化包括上皮細胞失去緊密連接和極性，上皮細胞呈現纖維細胞形態以及增強的細胞移動性。囊性纖維變性跨膜電導調節器（CFTR）是一種廣泛表達於上皮細胞的氯離子和碳酸根離子通道。研究證實，CFTR 的蛋白轉運與上皮連接的形成和功能有關，同時 CFTR 的表達受到 EMT 誘導因子 HIF-1 和 TGF-β 的反向調節。另外，CFTR 的表達和功能被證實參與 EMT 相關信號分子 Wnt 和 NF-κB活性的調節。基於上述發現，本研究旨在闡述 CFTR 與 EMT 的相關性。 / CFTR 參與的腎上皮 EMT 以及後續的腎纖維化首先被關注。實驗表明，在腎上皮細胞（MDCK）中，小 RNA 介導的 CFTR 基因敲降或抑製劑引起的CFTR 通道功能缺陷均引起間充質細胞特徵的出現，包括纖維狀細胞形態、細胞連接分子 E-cadherin, ZO-1 和 Occludin 表達下調和間充質細胞標誌分子 Vimentin 和 N-cadherin 上調、上皮細胞跨膜電阻減低以及細胞遷徙能力的增強。有趣的是，在單側尿道結紮的腎纖維化模型中，CFTR 表達被顯著下調。同時，動物實驗證實一個最常見的 CFTR 分子突變（deltaF508 -/-）增加了單側尿道結紮導致的腎纖維化的程度。另外，在缺氧引起的 EMT 過程中CFTR 的表達顯著下調；同時，腎纖維化模型中，HIF-1 和 CFTR 的表達呈現負相關。結果提示，生理及病理的條件下，氧氣的調節可能作為 CFTR 下調及其後續事件的誘因。進一步實驗發現，CFTR 功能抑製或基因突變可以引起Wnt 的富集和 β-catenin 的細胞核轉移。基於以上的實驗結果，在腎纖維化的過程中，CFTR 參與了缺氧引起的 EMT 過程，並通過激活 Wnt/β-catenin 信號調節相關的下游因子。 / 第二部分集中探究了 CFTR 在癌細胞EMT 及腫瘤轉移中的作用及機制。實驗證實，在 TGF-β 誘導的腫瘤細胞 EMT 過程中，CFTR 表達被抑制。TGF-β 可能作為病理狀態下的調節因子，引起腫瘤細胞中 CFTR 表達下調及EMT。抑制 CFTR 通道功能或敲降其蛋白表達導致明顯的間充質細胞特徵，這一變化在不同來源的腫瘤細胞系中呈均一性。相對地，過表達 CFTR 引起細胞遷移和侵潤能力地顯著下降。在體實驗顯示，CFTR 表達與腫瘤的轉移能力呈現負相關。進一步機制研究證明，CFTR 通過調節多重的通路參與 EMT的過程。首先，uPA 的表達和活性受到 CFTR 的反向調節，並且這一調節作用是由激活的 NF-κB 介導的。其次，抑制 CFTR 通道功能引起 β-catenin 的細胞核轉移。 / 綜上所述，研究發現 CFTR 通過調節多重信號參與腎上皮及腫瘤細胞的 EMT。同時，研究顯示 CFTR 的表達和功能與腎纖維化及腫瘤轉移有關。此研究對相關疾病的診斷和預後具有潛在的提示作用。 / Epithelial-Mesenchymal Transition (EMT) is an intricate process by which epithelial cells lose their epithelial characteristics and acquire a mesenchymal-like phenotype. It is essential for numerous physiological and pathological processes, such as embryonic development, tissue fibrosis and cancer metastasis. The dramatic phenotype changes of EMT include loss of tight junctions and polarity, acquisition of a fibroblastic morphology and increased motility. The cystic fibrosis transmembrane regulator (CFTR) is known as an anion channel and extensively expressed in a variety of epithelial cells. Interestingly, the apical membrane expression of CFTR is reported to be required for the normal organization and function of epithelial junctions. Moreover, EMT inducers, such as HIF-1 and TGF-β, are known to suppress the expression of CFTR in epithelial cells. In addition, CFTR has been reported to be associated with expression and/or activity of Wnt and NF- κB, key factors known to be involved in EMT. Thus, we hypothesized that CFTR might play an important role in EMT. / In the first part of the study, the involvement of CFTR in EMT of kidney epithelial cells and renal fibrosis was investigated. Our experiments revealed that suppression of CFTR by either inhibitor or knockdown induced EMT in Madin- Darby canine kidney epithelial cells (MDCK). This was accompanied by the appearance of fibroblastic morphology, with reduced expression of epithelial junction proteins E-cadherin, ZO-1 and occludin and accumulated expression of the mensenchymal markers vimentin and N-cadherin, as well as reduced transepithelial resistance (TER) and enhanced migratory ability. Interestingly, the expression of CFTR was found significantly down-regulated in unilateral urethral obstruction (UUO) kidney. In addition, CFTR mutant (deltaF508 -/-), the most common mutation found in CF patients, increased the risk of renal fibrosis in UUO model. Our results showed that the expression of CFTR down-regulated in hypoxia induced-EMT in MDCK, and the expression of hypoxia-sensitive transcription factor, HIF-1, is inversely correlated with CFTR in UUO kidney. Accumulation of Wnt and translocation of β-catenin were also observed in CFTR inhibitors-treated MDCK and deltaF508 -/- UUO mice. Taken together, these findings suggest that CFTR may be involved in mediating hypoxia-induced EMT by influencing the Wnt/β-catenin signaling contributing to renal fibrosis. / In the second part of the study, the role of CFTR in EMT during cancer metastasis and the underlying mechanisms were investigated. Recent studies have demonstrated that cancer cells may reinstitute properties of developmental EMT including enhanced migration and invasion. On the other hand, the reverse process, known as mesenchymal-to-epithelial transition (MET), has been implicated in forming a secondary metastatic tumor. Using various tissue-derived cancer cell lines including human colorectal cancer cell line LIM1863, human lung carcinoma cell line A549, and human breast cancer cell lines MCF7 and MDA-MB-231, we report that induction of EMT by TGF-β sharply reduces CFTR expression in various tissue derived cancer cell lines, while overexpression of CFTR can reverse the TGF-β- induced EMT phenyotype. Interfering with CFTR function either by its specific inhibitor or lentiviral miRNA-mediated knockdown mimicks TGF-β-induced EMT and enhances cell migration and invasion. Ectopic overexpression of CFTR in a highly metastatic cancer cell lines downregulates EMT markers and suppresses cell invasion and migration in vitro, as well as the ability of the cells to metastasize to the lung in vivo. The EMT-suppressing effect of CFTR is found to be associated with its ability to alter NF-κB targeting urokinase-type plasminogen activator (uPA) and the nuclear translocation of β-catenin. Taken together, the present study has demonstrated a previously undefined role of CFTR as an EMT suppressor in cancer. / In summary, our findings have demonstrated a regulatory role of CFTR in EMT in both normal kidney epithelial cell line and various cancer cell lines. We conclude that CFTR plays important roles in renal fibrosis and cancer progression/metastasis by modulating EMT process through multiple pathways. The insights afforded by these studies will provide critical new information about the function of CFTR as a suppressor of EMT, which may have potential application in diagnosis and prognosis of fibrosis and cancer. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Zhang, Jieting. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 136-150). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Epithelial-Mesenchymal Transition --- p.1 / Chapter 1.1.1 --- Concept and features of EMT --- p.2 / Chapter 1.1.2 --- Roles of EMT in development and diseases --- p.10 / Chapter 1.1.3 --- The Regulators of EMT --- p.13 / Chapter 1.2 --- Structure and function of CFTR --- p.18 / Chapter 1.2.1 --- General structure and channel functions of CFTR --- p.18 / Chapter 1.2.2 --- Gene mutations and CF --- p.18 / Chapter 1.3 --- Potential role of CFTR in EMT --- p.20 / Chapter 1.3.1 --- CFTR in formation of cell-cell junction and membrane polarity --- p.20 / Chapter 1.3.2 --- CFTR and EMT inducers --- p.21 / Chapter 1.3.3 --- CFTR and EMT related pathways and factors --- p.22 / Chapter 1.4 --- Hypothesis and aim of the study --- p.22 / Chapter Chapter 2 --- CFTR involves in hypoxia induced EMT in renal fibrosis --- p.24 / Chapter 2.1 --- Abstract --- p.24 / Chapter 2.2 --- Introduction --- p.25 / Chapter 2.3 --- Results --- p.30 / Chapter 2.3.1 --- Knockdown of CFTR induces EMT in MDCK --- p.30 / Chapter 2.3.2 --- Inhibition of CFTR channel function induces EMT in MDCK --- p.30 / Chapter 2.3.3 --- CFTR is downregulated during the process of renal fibrosis --- p.36 / Chapter 2.3.4 --- CFTR defect increases the risk of renal fibrosis --- p.39 / Chapter 2.3.5 --- Hypoxia/HIF-1α rather than TGF-β as the inducer of CFTR repression during EMT and renal fibrosis --- p.44 / Chapter 2.3.6 --- CFTR as a negative regulator of Wnt/β-catenin signaling in renal epithelium --- p.51 / Chapter 2.4 --- Discussion --- p.57 / Chapter 2.5 --- Conclusion --- p.61 / Chapter 2.6 --- Materials and Methods --- p.61 / Chapter 2.6.1 --- Cell culture and treatments --- p.61 / Chapter 2.6.2 --- Plasmids and transient transfection --- p.62 / Chapter 2.6.3 --- Western blot analysis --- p.62 / Chapter 2.6.4 --- Measurement of trans epithelial electric resistance --- p.64 / Chapter 2.6.5 --- Wound-healing migration assay --- p.64 / Chapter 2.6.6 --- Animals and Obstructive model --- p.64 / Chapter 2.6.7 --- HE and Masson's trichrome stain --- p.65 / Chapter 2.6.8 --- Immunofluorescent and immunohistochemistry staining --- p.65 / Chapter 2.6.9 --- Statistical analysis --- p.66 / Chapter Chapter 3 --- CFTR down-regulation mediates EMT during cancer metastasis --- p.67 / Chapter 3.1 --- Abstract --- p.67 / Chapter 3.2 --- Introduction --- p.67 / Chapter 3.3 --- Results --- p.73 / Chapter 3.3.1 --- Repression of CFTR during TGF-β induced EMT in cancer cells --- p.73 / Chapter 3.3.2 --- Hypoxia does not have significant effect on CFTR expression --- p.78 / Chapter 3.3.3 --- Repression of CFTR channel function induces EMT in cancer cells --- p.81 / Chapter 3.3.4 --- Knockdown/overexpression of CFTR induces/inhibits EMT and malignant phenotypes --- p.84 / Chapter 3.3.5 --- CFTR inhibits lung metastasis in vivo --- p.94 / Chapter 3.3.6 --- Anti-metastatic effect of CFTR involves NF-κB targeting uPA --- p.104 / Chapter 3.3.7 --- Correlation between CFTR and β-catenin --- p.112 / Chapter 3.4 --- Discussion --- p.116 / Chapter 3.5 --- Conclusion --- p.122 / Chapter 3.6 --- Materials and methods --- p.122 / Chapter 3.6.1 --- Cell culture and treatments --- p.122 / Chapter 3.6.2 --- Lentiviral production and transduction --- p.123 / Chapter 3.6.3 --- Plasmids and stable transfection --- p.124 / Chapter 3.6.4 --- RT-PCR analysis --- p.124 / Chapter 3.6.5 --- Western blot analysis --- p.126 / Chapter 3.6.6 --- Immunofluorescence staining --- p.126 / Chapter 3.6.7 --- Cell growth assay --- p.127 / Chapter 3.6.8 --- Migration assay --- p.127 / Chapter 3.6.9 --- Invasion assay --- p.128 / Chapter 3.6.10 --- In vivo tumor growth assay --- p.128 / Chapter 3.6.11 --- In vivo metastasis assay --- p.128 / Chapter 3.6.12 --- Human EMT PCR array --- p.129 / Chapter 3.6.13 --- uPA activity assay --- p.129 / Chapter 3.6.14 --- Statistical analysis --- p.129 / Chapter Chapter 4 --- General discussion --- p.130 / Chapter 4.1 --- Normal function of CFTR in epithelial polarity and barrier function --- p.130 / Chapter 4.2 --- Down-regulation of CFTR is associated with EMT-related diseases --- p.131 / Chapter 4.3 --- CFTR functions as a central mediator of different EMT signals --- p.132 / Chapter 4.4 --- Future directions --- p.134 / Chapter 4.5 --- Conclusion --- p.135 / References --- p.136 / Declaration --- p.151

Pour ses activités immuno-activatrices, l’Interleukine-15 (IL-15) est actuellement considérée comme un candidat de choix pour le traitement des tumeurs solides, en particulier le carcinome rénal, une tumeur très agressive et résistante aux chimio- et immunothérapies. Bien qu’actuellement testée en essai clinique, les fonctions de la cytokine sur la composante rénale restent peu étudiées. Dans ces travaux, nous avons évalué le rôle de l’IL-15 sur les cellules épithéliales rénales normales et tumorales ainsi que sur une sous-population de cellules souches du cancer (CSC) très résistante aux thérapies conventionnelles. Nos résultats montrent que l’IL-15 induit la différenciation des CSC rénales en cellules épithéliales non tumorigéniques et plus sensibles aux agents cytotoxiques, confortant ainsi l’utilisation de la cytokine dans des stratégies anti-tumorales. Nos travaux révèlent cependant que l’IL-15 favorise la transition épithélio-mésenchymateuse des cellules du carcinome rénal, une action pro-tumorale à considérer dans le développement de nouvelles approches thérapeutiques. / The ability of Interleukin-15 (IL-15) to activate many immune antitumor mechanisms makes it a good candidate for application in solid tumors therapy, particularly renal cell carcinoma which is a highly aggressive and resistant cancer. Although IL-15 is being currently used in clinical trials, the function of the cytokine on the kidney’s components is poorly described. In this work, we evaluated the role of IL-15 on renal normal and tumor epithelial cells as well as a subpopulation of cancer stem cells (CSC) highly resistant to conventional therapies. Our results show that IL-15 induces the differentiation of renal CSC in non-tumorigenic epithelial cells more sensitive to cytotoxic agents, supporting the use of the cytokine in antitumor strategies. Our experiments show, however, that IL-15 promotes epithelial-mesenchymal transition of renal cell carcinoma cells, a pro-tumor action to be highly considered in the development of new therapeutic approaches.

Le cancer de la prostate est le cancer le plus fréquent chez l’homme et représente la troisième cause de mortalité par cancer en France. Depuis 2004, le docetaxel est le traitement de référence du cancer de la prostate métastatique résistant à la castration (mCRPC). Cependant, malgré le bénéfice de survie obtenu, près de la moitié des patients traités développent une résistance à la chimiothérapie. L’objectif de mon projet de thèse consiste à identifier un prédicteur moléculaire permettant de sélectionner les patients qui vont répondre à la chimiothérapie par docetaxel. Par l’étude du mécanisme moléculaire associé avec le développement de la résistance, mon second objectif est d’identifier de nouvelles cibles thérapeutiques afin de contourner cette résistance.Dans ce but, les profils d’expression de gènes et de microARNs différentiellement exprimés dans plusieurs modèles cellulaires de cancer de prostate résistants au docetaxel ont été établis. L’intégration des données issues de ces analyses haut-débit a suggéré que la transition épithélio-mésenchymateuse (EMT) intervenait dans le mécanisme de résistance au docetaxel. La dissection du mécanisme d’EMT observé dans les modèles cellulaires a permis d’identifier SHISA3 comme une nouvelle protéine régulatrice de ce processus. Le gène SHISA3, alors jamais décrit chez l’Homme, est fortement sous-exprimé dans les modèles résistants au docetaxel présentant un phénotype mésenchymateux, mais également dans de multiples tumeurs humaines. L’inhibition de SHISA3 dans les modèles cellulaires sensibles induit une EMT complète, caractérisée par la perte des jonctions cellulaires, l’expression des facteurs de transcription mésenchymateux et l’augmentation des capacités migratoires. L’étude du mécanisme d’action de SHISA3 nous a permis de mettre en évidence l’interaction de SHISA3 avec le TGFβRII. Nous avons montré dans les cellules résistantes au docetaxel que l’inhibition pharmacologique de la voie du TGFβ provoque une sensibilisation au docetaxel, démontrant l’importance de la régulation de cette voie dans la résistance à la chimiothérapie. En parallèle de ce travail, nous avons établi un modèle de cancer de la prostate résistant au docetaxel chez la souris. L’obtention de ce modèle est cruciale pour réaliser la validation préclinique des thérapies visant à contourner les mécanismes de résistance au docetaxel. Les tumeurs obtenues dans ce nouveau modèle sont caractérisées par une sous-expression de SHISA3 et par l’expression des marqueurs d’EMT. Ce modèle nous permettra de valider in vivo le potentiel thérapeutique de l’association d’un inhibiteur de la voie du TGFβ avec le docetaxel. De manière intéressante, nous avons observé in vivo que l’expression de SHISA3 est corrélée à la réponse au traitement par docetaxel. Ces résultats suggèrent que SHISA3 pourrait être un biomarqueur de réponse à la chimiothérapie. / Prostate cancer is the most common cancer in men and the third leading cause of cancer mortality in France. Since 2004, docetaxel is the standard treatment for metastatic castration-resistant prostate cancer (mCRPC). However, nearly half of treated patients develop resistance to chemotherapy. The aim of my thesis is to identify molecular predictors to select patients who will respond to docetaxel chemotherapy. My second goal is to identify new therapeutic targets to overcome this resistance, by studying the molecular mechanisms involved in the development of resistance.To this purpose, genes and microRNAs expression profiles were established in several cellular models of docetaxel-resistant prostate cancer. The integration of these high-throughput data suggested that the epithelial-mesenchymal transition (EMT) was involved in the mechanism of docetaxel resistance. Deciphering the EMT mechanism observed in our cellular models allowed the identification of SHISA3 as a new regulator of this process. SHISA3 is highly under-expressed in docetaxel resistant cells which present a mesenchymal phenotype. Interestingly, SHISA3 is also down-regulated in a large variety of human tumors. The inhibition of SHISA3 in sensitive cells induced a complete EMT, characterized by loss of cellular junctions, expression of mesenchymal transcription factors, and increased migratory capacity. The study of its mechanism of action allowed us to highlight the interaction of SHISA3 with TGFβRII. We showed in docetaxel-resistant cells that pharmacological inhibition of the TGFβ signalling pathway induces sensitization to docetaxel, demonstrating the importance of the regulation of this pathway in the resistance to chemotherapy.In parallel, we developed a docetaxel-resistant prostate cancer model in mice. The establishment of this model is critical for the preclinical validation of new targeted therapies. Tumors obtained from this new model are characterized by the under-expression of SHISA3 and the expression of EMT markers. This model will allow the validation of the therapeutic potential of co-treatment with docetaxel and TGFβ signalling pathway inhibitors in vivo. Interestingly, we observed that SHISA3 expression is correlated with response to docetaxel treatment in vivo. These results suggest that SHISA3 could be a biomarker of response to docetaxel chemotherapy.

L’infection chronique par le virus de l’hépatite C (VHC) conduit au développement de la fibrose et de la cirrhose qui risque d’évoluer vers le carcinome hépatocellulaire (CHC). La protéine de capside du VHC interagit avec de nombreuses protéines de l’hôte et en particulier avec Smad3, protéine majeure de la voie de signalisation du transforming growth factor beta (TGF-Β). Mon travail de thèse consistait à étudier les conséquences biologiques de l’interaction entre la protéine de capside avec la voie de signalisation du TGF-Β. Le VHC présente une grande variabilité génétique et des travaux du laboratoire ont montré l’existence de séquences différentes de protéines de capside du virus entre les régions tumorales (cT) et cirrhotiques (cNT) d’un même sujet. Nous avons montré que ces différentes protéines de capside exprimées dans des hépatocytes orientent les réponses biologiques du TGF-Β vers la promotion tumorale en diminuant l’apoptose et en augmentant la transition épithelio-Mésenchymateuse (TEM) en particulier le variant cT. Cet effet est attribué à la capacité de la protéine de capside de diminuer l’activité transcriptionnelle de Smad3. De plus, les variants de la protéine de capside activent le TGF-Β latent via l’augmentation de l’expression de la trombospondine. L’un des marqueurs classiquement exprimé au cours d’une TEM est l’alpha-Actine musculaire lisse (αSMA). Nous avons montré qu’une autre isoforme, la γSMA, était polymérisée dans les cellules hépatiques développant une TEM. L’expression de γSMA a été retrouvée sur des coupes de CHC et a pu être significativement corrélée à la fois avec des marqueurs de la TEM, des marqueurs progéniteurs et avec l’agressivité de la tumeur.Ce travail apporte une meilleure compréhension du rôle de la protéine de capside dans la fibrose hépatique liée à l’infection virale. En effet, la protéine de capside du VHC agit à la fois de façon autocrine dans les hépatocytes en modulant les réponses du TGF-Β vers la promotion tumorale et de façon paracrine, en affectant l’activation des cellules étoilées en myofibroblastes par le TGF-Β activé. / Chronic HCV infection) may progress to liver fibrosis, cirrhosis and hepatocellular carcinoma (HCC). HCV core binds several cellular proteins and in particular Smad3, a major protein of transforming growth factor beta (TGF-Β) signalling.. The aim of this study was to determine the implication of HCV core protein in TGF-Β responses. High genetic variability is a characteristic of HCV and it was previously shown that HCV core protein isolated from tumour (cT) or adjacent non-Tumour (cNT) livers displayed different sequences. Both were able to shift TGF-B responses from tumour suppressor to tumour promotor by decreasing hepatocyte apoptosis and increasing epithelial-Mesenchymal transition (EMT). Core cT was more potent than core cNT to promote this effect that was mainly attributed to the capacity of HCV core to alleviate Smad3 activity. Moreover, HCV core protein activated the latent form of TGF-Β through increased thrombospondin expression. It is commonly accepted that αSMA (alpha smooth muscle actin) is a hallmark of EMT. In the current study another SMA isoform, γSMA was found to be polymerized during hepatocyte EMT. γSMA was expressed in HCC tissues and correlated with EMT, stem cell and aggressiveness markers. In conclusion, this work contributed to a better understanding of the HCV core role in hepatitis fibrosis and HCC related to HCV. Indeed, HCV core might act both as an autocrine and paracrine way by modulating TGF-Β responses within hepatocytes and by activating hepatic stellate cells in stromal environment through its capacity to activate TGF-Β.

Squamous cell carcinoma of the head and neck (HNSCC) is an extremely common and devastating disease with a bleak prognosis. Despite intensive research, survival rates have not improved over the past 30 years principally due to untreatable recurrent/metastasising disease. Feline oral squamous cell carcinoma (FOSCC) is an equally common disease in cats with an even less favourable prognosis than humans. Human and feline squamous cell carcinomas share similar etiopathogenesis, molecular markers, tumour biology and treatment thus making FOSCC an excellent model for HNSCC. Epithelial to mesenchymal transition (EMT), under the direction microRNAs (miRNAs/mirs) could be a key driver in oncogenic transformation and chemoresistance. The aim of this study was to induce resistance to characterise the EMT/resistance phenotype and to investigate whether common miRNA-mediated pathways are present in HNSCC and FOSCC that drive this phenomenon. We used epidermal growth factor (EGFR)-inhibitor gefitinib to induce resistance in HNSCC and FOSCC and investigated the associated EMT-related molecular changes. In vitro and in vivo invasive and migratory properties of both species were explored to determine whether resistance and/or EMT status conferred a functional advantage. We determined the miRNA expression pattern during acquisition of resistance to gefitinib in both species by next generation sequencing and screened candidate miRNAs as potential therapeutics. We found that gefitinib-resistance produced a previously unrecognised biphasic response that consisted of two distinct phenotypes, a highly invasive mesenchymal phenotype during early resistance, and a more epithelial phenotype associated with established resistance. The biphasic nature of this transition may prove critical in establishing effective therapeutic targets and the timing of treatment to overcome resistance or in preventing local invasion or metastatic spread of squamous cell carcinoma. We found that the major anti-apoptotic PI3K/AKT pathway was activated in transitioning and resistant cells of both species as demonstrated upregulation of AKT, pAKT and c-FLIP together with inactivation of PTEN by phosphorylation. This indicates that avoidance of apoptosis may be a major pathway in resistance that could be targeted therapeutically. We showed that three miRNAs were differentially expressed in both gefitinib-resistant human and feline cell lines: miR-107 was downregulated, and miR-551b and miR-574 were upregulated. These microRNAs provide potential therapeutic targets in the fight against drug resistance in head and neck cancer although much further research needs to be conducted to elucidate the complex network of interactions that may be affected by targeting these powerful regulatory molecules.