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

Studies for maximizing value of antibody drugs against tumors / 抗がん治療における抗体薬の価値最大化に向けた研究

Kashima(Yamashita), Yoriko 25 November 2014 (has links)
京都大学 / 0048 / 新制・論文博士 / 博士(農学) / 乙第12879号 / 論農博第2806号 / 新制||農||1028(附属図書館) / 学位論文||H26||N4878(農学部図書室) / 31597 / (主査)教授 植田 和光, 教授 植田 充美, 教授 矢﨑 一史 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DFAM
2

Targeted therapy sensitivity and resistance in solid malignancies

Jokinen, E. (Elina) 28 October 2014 (has links)
Abstract Cancer is a major global killer and a challenge for the healthcare worldwide. Earlier cancer has been treated with surgery, radiation, chemotherapy and hormonal therapy. Unfortunately the efficiency of these therapies has shown to be limited and this has raised an enthusiasm for development of new, targeted cancer therapies that are based on activated oncogenes. The challenge of the targeted therapies is therapy resistance, de novo, adaptive and acquired. This work investigated targeted therapy sensitivity and resistance in lung cancer, breast cancer, colorectal cancer, and melanoma cell lines. The results of this study indicate that in some non-small cell lung cancer cell lines, dual PI3K and MEK inhibition is a more efficacious treatment than inhibition of either solely. It was also showed that the maximal effect of the dual inhibition can be achieved with alternative dosing schedules that are potentially more tolerable in clinical use. Furthermore, by combining ABT-263, entinostat or dasatinib to the dual PI3K and MEK inhibition, the efficiency of the therapy can be increased. Bcl-xl downregulation is a major determinant of the apoptotic response to the triple inhibitor treatment. The current work showed that cancer stem cells can mediate resistance to targeted therapies. Since these cells follow the stochastic model, concurrent therapy with a targeted agent and a stem cell targeting drug might be needed for maximal therapeutic efficiency. This study also showed that Gö6976 acts as a potent inhibitor of mutant EGFR despite the presence of T790M, the most important mechanism of acquired resistance for EGFR tyrosine kinase inhibitors in lung cancer, both in vitro and in vivo. / Tiivistelmä Syöpä on yksi johtavia kuolemanaiheuttajia ja tauti on maailmanlaajuinen haaste terveydenhuollolle. Perinteiset syöpähoidot käsittävät kirurgian, sädehoidon, kemoterapian ja hormonaalisen hoidon, mutta näiden rinnalle on noussut uusia, aktivoituneiden onkogeenien signaalien estoon perustuvia hoitoja. Tämä työ tutki kohdennettuja syöpähoitoja ja näihin hoitoihin liittyvää resistenssiä keuhko-, rinta- ja paksusuolen syövän sekä melanooman solulinjoissa. Tulokset osoittavat, että joissakin ei-pienisoluisen keuhkosyövän solulinjoissa yhdistetty PI3K- ja MEK-esto aiheuttaa tehokkaamman vasteen kuin kummankaan signaalireitin esto yksistään. Tässä työssä näytettiin myös, että maksimaalinen vaste yhdistetylle PI3K- ja MEK-estolle voidaan saavuttaa vaihtoehtoisilla annostelutavoilla, jotka ovat voisivat olla paremmin siedettyjä kliinisessä käytössä kuin kahden lääkkeen jatkuva annostelu. Tämä tutkimus osoitti lisäksi, että kaksoiseston tehokkuutta voidaan lisätä yhdistämällä hoitoon kolmas lääkeaine, ABT-263, entinostaatti tai dasatinibi. Bcl-xl proteiinilla on keskeinen rooli apoptoottisen vasteen määrittäjänä näille kolmen lääkkeen käsittelyille. Tämä työ osoitti, että syövän kantasolut voivat välittää resistenssiä kohdennetuille syöpähoidoille. Nämä solut noudattavat niin kutsuttua stokastista mallia, joten parhaan vasteen saaminen saattaa edellyttää että hoito kohdentuu sekä erilaistuneisiin että kantasolutyyppisiin syöpäsoluihin. Tässä tutkimuksessa osoitettin lisäksi, että Gö6976 toimii mutatoituneen EGFR:n estäjänä, huolimatta kehittyvää keuhkosyövissä resistenssiä välittävästä T90M mutaatiosta, sekä in vitro -että in vivo -malleissa.
3

Meta-análise : estudos da efetividade de terapias com fármacos alvo moleculares para o tratamento do tumor renal metastático / Meta-analysis : study of effectiveness of drug therapy with molecular target for treatment of renal tumor metastatic

Senatore, Marcela Andrea Duran Haun, 1974- 24 August 2018 (has links)
Orientadores: Wagner Eduardo Matheus, Ubirajara Ferreira / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-24T12:07:43Z (GMT). No. of bitstreams: 1 Senatore_MarcelaAndreaDuranHaun_D.pdf: 1829482 bytes, checksum: bc20dee71d7524f229d7b76160f9e38b (MD5) Previous issue date: 2014 / Resumo: Atualmente existem diferentes agentes para o tratamento do câncer renal avançado. O objetivo principal desse trabalho foi realizar revisão sistemática com meta-análise dos estudos clínicos randomizados que compararam: sorafenibe, sunitinibe, bevacizumabe, temsirolimus e everolimus ao interferon-?. Para isto foi realizada revisão sistemática da literatura em diferentes bancos de dados: EMBASE, LILACS e PUBMED, identificando estudos clínicos randomizados que compararam as terapias alvo moleculares (TAM) disponíveis versus interferon-alfa para tratamento de pacientes com câncer renal avançado. Para o tratamento de 1a linha foram encontrados 10 estudos que avaliaram as terapias com sunitinibe, sorafenibe, bevacizumabe e temsirolimus; e três estudos que avaliaram o sorafenibe e everolimus como tratamento de 2a linha. O Risco Relativo (RR) da sobrevida livre de progressão (SLP) dos estudos de 1a linha foi de 0.83, intervalo de confiança (IC) [0.78-0.87] com I2= 94% e p<0.00001. Os melhores resultados foram: o estudo do sunitinibe, 0.38, IC [0.25-0.58], do bevacizumabe com RR de 0.62, IC [0.47-0.83] e do temsirolimus, 0.78, IC [0.70-0.87]. A meta-análise não demonstrou benefício quanto à sobrevida global (SG), no tratamento de 1a linha com sunitinibe e temsirolimus. Os tratamentos de 1ª linha com sorafenibe e bevacizumabe não associaram benefícios clínicos significativos. Não foi possível realizar meta-análise nos estudos do tratamento de 2a linha, pois, as populações eram diferentes. Logo, para o tratamento de 1a linha, sunitinibe e temsirolimus foram a terapias mais efetivas, quanto a SLP. No tratamento de 2a linha, o sorafenibe e everolimus foram relacionados à melhora da SLP. Em todos os estudos de 1a linha os pacientes não apresentaram melhora de SG e a qualidade metodológica não foram adequadas, portanto esses resultados devem ser analisados com cautela / Abstract: Currently, there are different agents for the treatment of advanced kidney cancer. The main aim of this study was to perform a systematic review and meta-analysis of randomized clinical trials that compared: sorafenib, sunitinib, bevacizumab, temsirolimus and everolimus. It was performed a systematic review of the literature in different databases: EMBASE, LILACS and PubMed, identifying randomized clinical trials that compared the available therapies target cells versus alpha-interferon for the patient treatments with advanced kidney cancer. For the treatment of first-line were found 10 studies that evaluated the therapy with sunitinib, sorafenib, bevacizumab and temsirolimus and three studies evaluating sorafenib and everolimus as a treatment second-line. The relative risk of progression free survival of first line studies was 0.83, confidence interval (CI) [0.78-0.87] with I2 = 94% and p <0.00001. The best results were: the study of sunitinib, 0.38, CI [0:25 to 0:58], bevacizumab with RR of 0.62, CI [0.47-0.83] and temsirolimus, 0.78, CI [0.70-0.87]. The meta-analysis showed no benefit on overall survival in first-line treatment with sunitinib and temsirolimus. The first-line treatment with sorafenib and bevacizumab not associated significant clinical benefits. Unable to perform meta-analysis on studies of second-line treatment, because the cohorts were different between them. For the treatment of first-line, sunitinib and temsirolimus were more effective therapies, as the progression free survival (PFS). In the second line treatment, sorafenib and everolimus was associated with improved PFS. In these studies, patients showed no improvement in overall survival (OS) and methodological quality were not adequate, so these results should be analyzed with caution / Doutorado / Fisiopatologia Cirúrgica / Doutora em Ciências
4

Administração intratumoral de uma toxina engenheirada ativada por uroquinase (UPA) e metaloproteinase (MMP) para o tratamento do melanoma oral canino: estudo piloto / Intratumoral administration of urokinase (uPA) and metalloproteinase (MMP)-activated engineered toxin for treatment of canine oral melanoma: pilot study

Nishiya, Adriana Tomoko 01 February 2018 (has links)
Os melanomas malignos em cães são uma das mais frequentes neoplasias diagnosticadas na cavidade oral. Infiltração local, recidiva (15-41%) e o alto potencial para metástases em linfonodos regionais (18-53%) e pulmões (23-27%) nos animais acometidos, conferem uma menor sobrevida (131-818 dias), ressaltando a necessidade e importância do estudo de novas terapias para o tratamento efetivo da doença. As uroquinases (UPA) e metaloproteinases (MMPs) são proteases superexpressas em uma variedade de células tumorais e raramente estão presentes em células fisiologicamente normais. A toxina do Bacillus anthracis é composta por três proteínas chamadas: fator letal (LF), fator de edema (EF) e antígeno protetor (PA). A toxina foi reengenheirada para a formação de dois tipos de PAs chamadas PAU2-R200A e PAL1-I207R, ativadas por UPA e MMPs da superficie das células tumorais, respectivamente, formando um complexo semelhante a um poro celular para permitir a internalização da LF. A citotoxicidade dessa associação reengenheirada PAU2-R200A, PAL1-I207R e LF ocorre quando a LF atinge o meio intracelular e causa a morte celular por interrupção da via de sinalização celular MAPkinase. O objetivo deste estudo é avaliar o potencial terapêutico da toxina reengenheirada do Bacillus anthracis, PAU2-R200A, PAL1-I207R e LF, dependentes de UPA e MMP, em melanomas orais de cães. Três etapas foram propostas para este estudo: o estudo in vitro da citotoxicidade de 5 linhagens de melanomas caninos submetidas à toxina reengenheirada, a avaliação da expressão de UPA e MMP em amostras parafinadas de melanoma oral canino e o tratamento intratumoral com a toxina modificada em cães com melanomas orais espontâneos. A linhagem GMGD2 foi a única que demonstrou sensibilidade à toxina estudada, apesar da concentração inibitória de 50% das células ter sido alta (IC50=4.964,16 mg/dl) em relação a linhagem controle HT29-RJ (IC50=179,47). As demais linhagens não demostraram redução da viabilidade celular com o aumento da concentração da toxina reengenheirada e não atingiram a IC50. Dentre as amostras de melanomas submetidos a imuno-histoquimica, 76,6% expressavam tanto uroquinases quanto metaloproteinases. Melanomas orais espontâneos de cães variando de 231,8 a 18601,6 mm3 em volume, sem evidências de metástases, foram tratados com as aplicações da toxina modificada por via intratumoral, previamente à excisão, realizada nos dias 07 ou 14 do tratamento. Dentre os animais estudados, todos apresentaram evolução favorável classificada como doença estável e resposta parcial. Somente um animal apresentou reação local. Nenhum dos pacientes apresentou efeito colateral sistêmico importante. Os resultados sugerem que existe potencial terapêutico da toxina reengenheirada do Bacillus anthracis sobre os melanomas bucais caninos e futuros ensaios clínicos são possíveis em cães e de extrema importância para o estudo mais aprofundado da toxina como nova terapia antineoplásica / Malignant melanomas in dogs are one of the most frequent malignancies diagnosed in the oral cavity. Local infiltration, recurrence (15-41%) and the high potential for regional lymph nodes metastases (18-53%) and lungs (23-27%) in the affected animals, confer a lower survival (131-818 days), emphasizing the necessity and importance of the study of new therapies for the effective treatment of the disease. Urokinase (UPA) and metalloproteinases (MMPs) are overexpressed proteases in a variety of tumor cells and are rarely present in normal physiological cells. Bacillus anthracis toxin is composed of three proteins called lethal factor (LF), edema factor (EF) and protective antigen (PA). The toxin was re-engineered for the formation of two types of PAs called PAU2-R200A and PAL1-I207R, activated by UPA and MMPs from the surface of tumor cells, respectively, forming a cell-like complex to allow the internalization of the LF. The cytotoxicity of this association PAU2-R200A, PAL1-I207R and LF occurs when LF reaches the intracellular environment and causes cell death by disruption of the MAPkinase cell signaling pathway. The objective of this study is to evaluate the therapeutic potential of UPA and MMP-dependent Bacillus anthracis toxin (PAU2- R200A, PAL1-I207R and LF) to treat oral melanomas in dogs. Three steps were proposed: cytotoxicity assay of 5 lineages of canine melanomas submitted to the reengineered toxin, immunohistochemistry study for UPA and MMP expression in paraffin samples of canine oral melanoma and intratumoral treatment with toxin in dogs with spontaneous oral melanomas. The lineage GMGD2 was the only one that showed sensitivity to the toxin studied, although 50% inhibitory concentration of the cells was high (IC50 = 4,964.16 mg / dl) in relation to the HT29-RJ control lineage (IC 50 = 179.47). Among the samples of melanomas submitted to immunohistochemistry, 76.6% expressed both urokinase and metalloproteinases. Spontaneous oral melanomas of dogs ranging volume from 231.8 to 18601.6 mm3 with no evidence of distant metastases, were treated with the applications of intratumoral re-engineered toxin prior to surgical excision. All of them has presented favorable evolution classified as stable disease and partial response. Only one animal had a local allergic reaction. None of the patients had a significant systemic side effects. The results suggest that there is a potential therapeutic effect of re-engineered anthrax toxin on canine melanomas and future clinical trials are possible in dogs and extremely important for further studies on the role of the B. anthracis toxin as a new antineoplastic agent
5

Administração intratumoral de uma toxina engenheirada ativada por uroquinase (UPA) e metaloproteinase (MMP) para o tratamento do melanoma oral canino: estudo piloto / Intratumoral administration of urokinase (uPA) and metalloproteinase (MMP)-activated engineered toxin for treatment of canine oral melanoma: pilot study

Adriana Tomoko Nishiya 01 February 2018 (has links)
Os melanomas malignos em cães são uma das mais frequentes neoplasias diagnosticadas na cavidade oral. Infiltração local, recidiva (15-41%) e o alto potencial para metástases em linfonodos regionais (18-53%) e pulmões (23-27%) nos animais acometidos, conferem uma menor sobrevida (131-818 dias), ressaltando a necessidade e importância do estudo de novas terapias para o tratamento efetivo da doença. As uroquinases (UPA) e metaloproteinases (MMPs) são proteases superexpressas em uma variedade de células tumorais e raramente estão presentes em células fisiologicamente normais. A toxina do Bacillus anthracis é composta por três proteínas chamadas: fator letal (LF), fator de edema (EF) e antígeno protetor (PA). A toxina foi reengenheirada para a formação de dois tipos de PAs chamadas PAU2-R200A e PAL1-I207R, ativadas por UPA e MMPs da superficie das células tumorais, respectivamente, formando um complexo semelhante a um poro celular para permitir a internalização da LF. A citotoxicidade dessa associação reengenheirada PAU2-R200A, PAL1-I207R e LF ocorre quando a LF atinge o meio intracelular e causa a morte celular por interrupção da via de sinalização celular MAPkinase. O objetivo deste estudo é avaliar o potencial terapêutico da toxina reengenheirada do Bacillus anthracis, PAU2-R200A, PAL1-I207R e LF, dependentes de UPA e MMP, em melanomas orais de cães. Três etapas foram propostas para este estudo: o estudo in vitro da citotoxicidade de 5 linhagens de melanomas caninos submetidas à toxina reengenheirada, a avaliação da expressão de UPA e MMP em amostras parafinadas de melanoma oral canino e o tratamento intratumoral com a toxina modificada em cães com melanomas orais espontâneos. A linhagem GMGD2 foi a única que demonstrou sensibilidade à toxina estudada, apesar da concentração inibitória de 50% das células ter sido alta (IC50=4.964,16 mg/dl) em relação a linhagem controle HT29-RJ (IC50=179,47). As demais linhagens não demostraram redução da viabilidade celular com o aumento da concentração da toxina reengenheirada e não atingiram a IC50. Dentre as amostras de melanomas submetidos a imuno-histoquimica, 76,6% expressavam tanto uroquinases quanto metaloproteinases. Melanomas orais espontâneos de cães variando de 231,8 a 18601,6 mm3 em volume, sem evidências de metástases, foram tratados com as aplicações da toxina modificada por via intratumoral, previamente à excisão, realizada nos dias 07 ou 14 do tratamento. Dentre os animais estudados, todos apresentaram evolução favorável classificada como doença estável e resposta parcial. Somente um animal apresentou reação local. Nenhum dos pacientes apresentou efeito colateral sistêmico importante. Os resultados sugerem que existe potencial terapêutico da toxina reengenheirada do Bacillus anthracis sobre os melanomas bucais caninos e futuros ensaios clínicos são possíveis em cães e de extrema importância para o estudo mais aprofundado da toxina como nova terapia antineoplásica / Malignant melanomas in dogs are one of the most frequent malignancies diagnosed in the oral cavity. Local infiltration, recurrence (15-41%) and the high potential for regional lymph nodes metastases (18-53%) and lungs (23-27%) in the affected animals, confer a lower survival (131-818 days), emphasizing the necessity and importance of the study of new therapies for the effective treatment of the disease. Urokinase (UPA) and metalloproteinases (MMPs) are overexpressed proteases in a variety of tumor cells and are rarely present in normal physiological cells. Bacillus anthracis toxin is composed of three proteins called lethal factor (LF), edema factor (EF) and protective antigen (PA). The toxin was re-engineered for the formation of two types of PAs called PAU2-R200A and PAL1-I207R, activated by UPA and MMPs from the surface of tumor cells, respectively, forming a cell-like complex to allow the internalization of the LF. The cytotoxicity of this association PAU2-R200A, PAL1-I207R and LF occurs when LF reaches the intracellular environment and causes cell death by disruption of the MAPkinase cell signaling pathway. The objective of this study is to evaluate the therapeutic potential of UPA and MMP-dependent Bacillus anthracis toxin (PAU2- R200A, PAL1-I207R and LF) to treat oral melanomas in dogs. Three steps were proposed: cytotoxicity assay of 5 lineages of canine melanomas submitted to the reengineered toxin, immunohistochemistry study for UPA and MMP expression in paraffin samples of canine oral melanoma and intratumoral treatment with toxin in dogs with spontaneous oral melanomas. The lineage GMGD2 was the only one that showed sensitivity to the toxin studied, although 50% inhibitory concentration of the cells was high (IC50 = 4,964.16 mg / dl) in relation to the HT29-RJ control lineage (IC 50 = 179.47). Among the samples of melanomas submitted to immunohistochemistry, 76.6% expressed both urokinase and metalloproteinases. Spontaneous oral melanomas of dogs ranging volume from 231.8 to 18601.6 mm3 with no evidence of distant metastases, were treated with the applications of intratumoral re-engineered toxin prior to surgical excision. All of them has presented favorable evolution classified as stable disease and partial response. Only one animal had a local allergic reaction. None of the patients had a significant systemic side effects. The results suggest that there is a potential therapeutic effect of re-engineered anthrax toxin on canine melanomas and future clinical trials are possible in dogs and extremely important for further studies on the role of the B. anthracis toxin as a new antineoplastic agent
6

Modulating Influenza and Heparin Binding Viruses’ Pathogenesis with Extrinsic Receptor Decoy Liposomes: A Dissertation

Hendricks, Gabriel L. 28 June 2013 (has links)
Influenza is a severe disease in humans and animals, causing upwards of 40,000 deaths every year in America alone. Influenza A virus (IAV) also causes periodic pandemics every 10 to 50 years, killing millions of people. Despite this, very few effective therapies are available. All strains of IAV are prone to developing resistance to antibodies due to the high mutation rate in the viral genome. Because of this mutation rate, a yearly vaccine must be generated before every flu season, and efficacy varies year to year. IAV has also mutated to escape several of the clinically-approved small molecule inhibitors. A therapeutic agent that targets a highly conserved region of the virus could bypass resistance and also be effective against multiple strains of IAV. IAV attachment is mediated by many individually weak hemagglutinin–sialic acid interactions that all together make a strong attachment to a host cell. Polymerized sialic acid analogs can recreate these interactions and block infection. However, they are not ideal therapeutics due to solubility issues and in vivo toxicity. We used liposomes as a novel means for delivery of the sialic acid-containing glycan, sialylneolacto-N-tetraose c (LSTc). LSTcbearing decoy liposomes form multivalent, polymer-like interactions with IAV. Decoy liposomes competitively bind IAV in hemagglutination inhibition assays and inhibit infection of target cells in a dose-dependent manner. LSTc decoy liposomes co-localize with IAV, while control liposomes do not. Inhibition is specific, as inhibition of Sendai virus and respiratory syncytial virus is not observed. In contrast, monovalent LSTc does not bind IAV or inhibit infectivity. LSTc decoy liposomes prevent the spread of IAV during multiple rounds of replication in vitro and extend survival of mice challenged with a lethal dose of virus. Considering the conservation of the hemagglutinin binding pocket and the ability of decoy liposomes to form high-avidity interactions with IAV hemagglutinin, our decoy liposomes have potential as a new therapeutic agent against emerging strains.
7

A Developed and Characterized Orthotopic Rat Glioblastoma Multiforme Model

Thomas, Sean C. 02 November 2020 (has links)
This thesis project serves to fill experimental gaps needed to advance the goal of performing pre-clinical trials using an orthotopic rat glioblastoma model to evaluate the efficacy of high-frequency electroporation (H-FIRE) and QUAD-CTX tumor receptor-targeted cytotoxic conjugate therapies, individually and in combination, in selectively and thoroughly treating glioblastoma multiforme. In order to achieve this, an appropriate model must be developed and characterized. I have transduced F98 rat glioma cells to express red-shifted firefly luciferase, which will facilitate longitudinal tumor monitoring in vivo through bioluminescent imaging. I have characterized their response to H-FIRE relative to DI TNC1 rat astrocytes. I have demonstrated the presence of the molecular targets of QUAD in F98 cells. The in vitro characterization of this model has enabled preclinical studies of this promising glioblastoma therapy in an immunocompetent rat model, an important step before advancing ultimately to clinical human trials. / Master of Science / Treating glioblastoma multiforme (GBM), a form of cancer found in the brain, has not been very successful; patients rarely live two years following diagnosis, and there have been no major breakthrough advances in treatment to improve this outlook for decades. We have been working on two treatments which we hope to combine. The first is high-frequency electroporation (H-FIRE), which uses electrical pulses to kill GBM cells while leaving healthy cells alive and blood vessels intact. The second is QUAD-CTX, which combines a toxin with two types of protein that attach to other proteins that are more common on the surface of GBM cells than healthy cells. We have shown these to be effective at disproportionately killing human GBM cells growing in a lab setting. Before H-FIRE and QUAD-CTX may be tested on humans, we need to show them to be effective in an animal model, specifically rats. I have chosen rat glioma cells that will behave similarly to human GBM and a rat species that will not have an immune response to them. I have made these cells bioluminescent so that we may monitor the tumors as they grow and respond to our treatments. I have also shown that QUAD-CTX kills these rat glioma cells, as does H-FIRE. Because of this work, we are ready to begin testing these two treatments in rats.
8

Modification of the duocarmycin pharmacophore enables CYP1A1 targeting for biological activity

Pors, Klaus, Loadman, Paul, Shnyder, Steven, Sutherland, Mark, Sheldrake, Helen M., Guino, M., Kiakos, K., Hartley, J.A., Searcey, M., Patterson, Laurence H. January 2011 (has links)
The identification of an agent that is selectively activated by a cytochrome P450 (CYP) has the potential for tissue specific dose intensification as a means of significantly improving its therapeutic value. Towards this goal, we disclose evidence for the pathway of activation of a duocarmycin analogue, ICT2700, which targets CYP1A1 for biological activity.
9

Targeting the Histone Acetyl-Transferase, RTT109, for Novel Anti-Fungal Drug Development: A Dissertation

Lopes da Rosa-Spiegler, Jessica 03 May 2012 (has links)
Discovery of new antifungal chemo-therapeutics for humans is limited by the large degree of conservation among eukaryotic organisms. In recent years, the histone acetyl-transferase Rtt109 was identified as the sole enzyme responsible for an abundant and important histone modification, histone H3 lysine 56 (H3K56) acetylation. In the absence of Rtt109, the lack of acetylated H3K56 renders yeast cells extremely sensitive to genotoxic agents. Consequently, the ability to sustain genotoxic stress from the host immune system is crucial for pathogens to perpetuate an infection. Because Rtt109 is conserved only within the fungal kingdom, I reasoned that Rtt109 could be a novel drug target. My dissertation first establishes that genome stability provided by Rtt109 and H3K56 acetylation is required for Candida albicans pathogenesis. I demonstrate that mice infected with rtt109 -/- cells experience a significant reduction in organ pathology and mortality rate. I hypothesized that the avirulent phenotype of rtt109 -/- cells is due to their intrinsic hypersensitivity to the genotoxic effects of reactive oxygen species (ROS), which are utilized by phagocytic cells of the immune system to kill pathogens. Indeed, C. albicans rtt109 -/- cells are more efficiently killed by macrophages in vitro than are wild-type cells. However, inhibition of ROS generation in macrophages renders rtt109 -/- and wild-type yeast cells equally resilient to killing. These findings support the concept that ability to resist genotoxic stress conferred by Rtt109 and H3K56 acetylation is a virulence factor for fungal pathogens and establish Rtt109 as an opportune drug- target for novel antifungal therapeutics. Second, I report the discovery of a specific chemical inhibitor of Rtt109 catalysis as the initial step in the development of a novel antifungal agent. We established a collaboration with the Broad Institute (Cambridge, MA) to perform a high-throughput screen of 300,000 compounds. From these, I identified a single chemical, termed KB7, which specifically inhibits Rtt109 catalysis, with no effect on other HAT enzymes tested. KB7 has an IC50 value of approximately 60 nM and displays noncompetitive inhibition regarding both acetyl-coenzyme A and histone substrates. With the genotoxic agent camptothecin, KB7 causes a synergistic decrease in C. albicans growth rate. However, this effect is only observed in an efflux-pump mutant, suggesting that this compound would be more effective if it were better retained intracellularly. Further studies through structure-activity relationship (SAR) modifications will be conducted on KB7 to improve its effective cellular concentration.
10

Weighted gene co-expression network analysis of colorectal patients to identify right drug-right target for potent efficacy of targeted therapy

Tripathi, Anamika 10 December 2017 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Colon rectal cancer (CRC) is one of the most common cancers worldwide. It is characterized by the successive accumulation of mutations in genes controlling epithelial cell growth and differentiation leading to genomic in-stability. This results in the activation of proto-oncogene(K-ras), loss of tumor suppressor gene activity and ab-normality in DNA repair genes. Targeted therapy is a new generation of cancer treatment in which drugs attack targets which are specific for the cancer cell and are critical for its survival or for its malignant behavior. Survival of metastatic CRC patients has approximately doubled due to the development of new combinations of stan-dard chemotherapy, and the innovative targeted therapies, such as monoclonal antibodies against epidermal growth factor receptor (EGFR) or monoclonal antibodies against vascular endothelial growth factor (VEGFR).The study is to exhibit the need for right drug-right target and provides a proof of principle for potent efficacy of molecular targeted therapy for CRC. We have performed the weighted gene co-expression network analysis for three different patient cohort treated with different targeted therapy drugs. The results demonstrates the variation across different treatment regime in context of transcription factor networks. New significant tran-scription factors have been identified as potential biomarker for CRC cancer including EP300, STAT6, ATF3, ELK1, HNF4A, JUN, TAF1, IRF1, TP53, ELF1 and YY1. The results provides guidance for future omic study on CRC and additional validation work for potent biomarker for CRC.

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