As neoplasias induzidas pela forma oncogênica da KRAS são doenças muito comuns, para as quais não existem terapias efetivas. Uma inibição direta da KRAS falhou em ensaios clínicos e esforços intensos tem sido feitos para identificar alvos de KRAS importantes para a oncogênese. Uma via promissora regulada por KRAS, que tem sido pouco explora a é a via dos microRNAs (miRNAs). Nossa meta foi identificar miRNAs regulados pela KRAS em células pulmonares e pancreáticas, que possam contribuir para o fenótipo oncogênico. Para alcançar esta meta nós usamos duas abordagens: (1) Nós investigamos o miRNA 486-5p como um alvo de KRAS em câncer de pâncreas e de pulmão. A expressão deste miRNA havia sido correlacionada positivamente com a presença de mutações em KRAS em pacientes portadores de câncer de cólon; (2) Nós usamos uma plataforma de microarranjo para identificar miRNAs diferencialmente expressos entre células humanas primárias imortalizadas pulmonares ou pancreáticas e suas linhagens isogênicas transformadas por KRAS. Na primeira abordagem, conseguimos mostrar que a expressão do miRNA 486-5p está correlacionada ao status de KRAS em células primárias pulmonares, mas não em células primárias pancreáticas. Além disso, geramos células pulmonares tanto com ganho e perda de função de KRAS e demonstramos que KRAS regula a expressão do miRNA 486-5p. Também de terminamos uma correlação negativa entre a expressão de KRAS e a expressão do alvo do miRNA 486-5p FoxO1, um supressor tumoral. Para avaliar como o miRNA 486-5p afeta as propriedades oncogênicas induzidas por KRAS, nós transfectamos oligonucleotídeos inibitórios para o miRNA 486-5p em células pulmonares positivas para mutações em KRAS. A inibição da expressão do miRNA 486-5p levou a uma redução da clonogenicidade e viabilidade celulares. Esta redução não está associada a um aumento de morte celular, mas a uma redução da proliferação celular. Interessantemente, a transfecção de oligonucleotídeos mímicos do miRNA 486-5p em células pulmonares negativas para mutações em KRAS ou em células com perda de função de KRAS por RNAi levou a um aumento da proliferação e clonogenicidade. Estes dados indicam que o miRNA 486-5p, não só é um alvo de KRAS em câncer de pulmão, mas também age como um oncomiR contribuindo para a proliferação celular induzida por KRAS. Na nossa segunda abordagem, nós identificamos 17 miRNAs com expressão aumentada e 3 com expressão diminuída em células primárias pancreáticas expressando KRAS oncogênica. Destes, 9 miRNAs foram foram também identificados por metanálise de dados de microarranjo publicados comparando amostras tumorais pancreáticas com amostras não tumorais. Apesar do experimento de microarranjo com as linhagens primárias pulmonares não ter produzido resultados estatisticamente significativos após a correção por FDR, uma tendência à expressão diferencial foi observada para vários miRNAs e nós validamos por qPCR a expressão diferencial dos miRNAs 720 e 139-3p. Em conclusão, nós conseguimos identificar miRNAs regulados pela KRAS tanto em células pulmonares, quanto pancreáticas. Um melhor entendimento das suas funções biológicas, bem como dos alvos por eles regulados nestes contextos, pode revelar novas vias para a exploração terapêutica. / KRAS-induced lung cancer is a very common disease, for which there are currently no effective therapies. Direct targeting of KRAS has failed in clinical trials and intense efforts are underway to identify KRAS targets that play a crucial role in oncogenesis. One promising KRAS-regulated pathway that has so far been overlooked is the micro RNA (miRNA) pathway. Our goal was to identify miRNAs regulated by oncogenic KRAS in lung and pancreatic cells that could contribute to the oncogenic phenotype. In order to achieve this goal we used two different approaches: (1) We investigated miRNA 486-5p as a KRAS target in lung and pancreatic cancer. The expression of this miRNA had been correlated to the presence of KRAS mutations in colon cancer patients; (2) we used a microarray platform to identify differentially expressed miRNAs between immortalized human primary pulmonary or pancreatic epithelial cell lines and their isogenic K-Ras-transformed counterparts. In our first approach, we were able to show that mi486-5p expression correlates with KRAS status in lung primary cells, but not in pancreatic primary cells. Furthermore, we generated lung cancer cells with either gain-of-function or loss-of-function of KRAS and demonstrated that KRAS regulates miRNA 486-5p in these cells. We also found, in all lung cell models analyzed, a negative correlation between expression of KRAS and expression of miR-486-5p target FoxO1, a tumor suppressor. In order to evaluate how miR-486-5p affects KRAS-induced oncogenic properties, we transfected miR-486-5p inhibitor oligonucleotides into KRAS-positive lung cancer cell lines. Inhibition of miR-486-5p expression leads to reduced clonogenic growth and viability. This reduction is not associated with increased cell death, but with decreased cell proliferation. Interestingly, transfection of miR-486-5p double-stranded RNA mimic oligonucleotides in to KRAS negative lung cancer cell lines or into cells with loss-of-function of KRAS by RNAi leads to enhanced proliferation and clonogenicity. These results indicate, not only that miR-486-5p is a KRAS target in lung cancer, but also that miR-486-5p acts as an oncomiR contributing to KRAS-induced cell proliferation. In our second approach, we identified 17 upregulated microRNAs and 3 downregulated microRNAs in the primary pancreatic cell line expressing KRAS. Of these, 9 miRNAs were also identified by a metanalysis of published microarray datasets comparing pancreatic cancer patient samples to non-cancerous pancreatic tissues. Even though our array experiment in the primary pulmonary cells did not produce statistically significant results after FDR correction, differential expression trends were seen for many miRNAs and we validated miRNAs 720 and 139-3p as differentially expressed. In conclusion we were able to identify miRNAs regulated by KRAS both in lung and pancreatic cancer cells. Further understanding of their biological function, as well as the targets they regulate in these settings, could uncover novel pathways for therapy design.

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京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22734号 / 医博第4652号 / 新制||医||1046(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 増永 慎一郎, 教授 川口 義弥 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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Ziel einer Definition der Resektabilität von Pankreaskarzinomen ist die Beschreibung von Kriterien, welche eine potentielle R0-Resektion ermöglichen. Wenngleich es zur Frage der Resektion bei positiven regionären Lymphknoten keine kontrollierten Studien gibt, ist weltweit die Resektion bei regionären Lymphknotenmetastasen Standard. Positive interaortokavale Lymphknoten stellen trotz Klassifikation als Fernmetastasen (M1) keine absolute Kontraindikation zur Resektion dar. Die mesenteriko-portale Venenresektion bei Verdacht auf Tumorinfiltration ist ein sicheres Verfahren. Sie hat keinen negativen Einfluss auf Morbidität, Mortalität und Überleben. Die En-bloc-Resektion der Arteria hepatica und der Arteria mesenterica superior wird sehr kontrovers diskutiert und sollte nur in Einzelfällen erwogen werden. Bei den meist fortgeschrittenen Karzinomen des Pankreaskorpus und -schwanzes kann durch eine En-bloc-Resektion des Truncus coeliacus eine höhere R0-Resektionsrate erreicht werden. / Pancreatic Cancer: Criteria and Limits of Resectability The aim of defining the resectability of pancreatic cancer is to determine the indication for potential R0 resection. Despite the absence of controlled trials, tumor resection in patients with regional lymph node involvement is a standard procedure worldwide. The involvement of interaortocaval lymph nodes is not an absolute contraindication for resection, although they are classified as distant metastasis (M1). Major pancreatic surgery can be safely combined with en-bloc resection of mesenteric, portal and splenic veins. Postoperative morbidity and mortality and long-term survival in patients with vein resection are comparable with those of patients without vein resection. The role of arterial en-bloc resection of the hepatic artery and the superior mesenteric artery is highly controversial and should be considered only in selected patients. For patients with locally advanced cancer of the body and tail of the pancreas distal pancreatectomy with en-bloc celiac axis resection offers an improved R0 resection rate. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Aims: The aim of this work was to determine whether a increased resting energy expenditure contributes to the nutritional risk for patients with pancreatic cancer. What the variability of resting energy expenditure is and whether it predicts weight loss. Another aim was to verify that lower protein-energy intake also has an impact on weight loss. Methods: Data for the diploma thesis were obtained from the project "Pancreatic Cancer: Metabolic Derangements Associated With Insulin Resistance", which takes place at the Department of Clinical Physiology of Metabolism at 2nd Department of internal medicine in the University Hospital Královské Vinohrady. The project includes 40 - 50 patients with pancreatic tumor resection per year. Data were collected from the beginning of December 2019 until the end of April 2020. The project is funded by the grant AZV NV19-01-00101. 10 consecutive patients (4 women and 6 men) with pancreatic cancer who had a complete dataset for analysis were selected for the research set for the diploma thesis. The patients underwent anthropometric examination, blood tests were taken, and indirect calorimetry was performed. Results: The first part of the research was focused on anthropometric parameters, parameters of nutritional status and the presence of cancer cachexia. The second...

This thesis focuses on the importance of intermediate products of biosynthetic and catabolic pathway of cholesterol. The aim of the first part of the thesis is mainly to investigate, whether statins (HMG- CoA reductase inhibitors) possess antitumor properties and to compare the differences in antitumor potential of individual statins. The other part of the thesis aims at the utilization of 7α-hydroxycholest-4-en-3-one (C4), a promising marker of cholesterol 7α-monooxygenase (CYP7A1) activity and bile acid malabsorption. We demonstrated antitumor effect of statins on an experimental model of pancreatic cancer. Individual statins, however, differed significantly in their efficacy, depending on their physico-chemical properties. Our data suggests, that the most likely (but not the only) mechanism of antitumor effect of statins is decreased prenylation of signaling proteins, especially Ras protooncogene. We set up a reliable method for measurement of C4, which facilitated our research in CYP7A1 regulation. We demonstrated, that promoter polymorphism -203A>C might affect CYP7A1 activity, that diurnal variability of CYP7A1 activity might be triggered by insulin, and that insulin resistance in patients with non-alcoholic fatty liver disease impedes the feedback regulation of CYP7A1, which may lead to disease...

Pancreatic cancer is one of the deadliest types of malignant diseases. Asymptomatic early tumour stages, tumour heterogeneity, cancer cell plasticity and unusually dense pancreatic stroma are responsible for the poor prognosis attributed to late diagnosis and therapy resistance. Therefore, targeting of a pivotal element common for any cell type within the tumour, e.g. mitochondria, may bring significant improvement. In this work, we demonstrate mitochondrial targeting of metformin, an anti-diabetic drug associated with reduced risk of developing pancreatic cancer, substantially increases accumulation of the compound in mitochondria. In consequence, we show that mitochondrially targeted metformin, MitoMet, eliminates pancreatic cancer cells in more than 1000-fold lower concentration than used for its parental compound. Following interaction with respiratory complex I (CI), MitoMet inhibits mitochondrial respiration, activates AMP-activated protein kinase pathway and causes depolarization of mitochondrial membrane potential in pancreatic cancer cells. Moreover, MitoMet induces cell cycle arrest and apoptosis, which is partially mediated via increased level of reactive oxygen species (ROS), and suppresses pancreatic tumour growth in vivo. Interestingly, SMAD4-deficient pancreatic cancer cells manifest...

Over 5000 flavonoids have been identified so far and many of these are known to have antineoplastic properties. The relationships between the targeting activities by these compounds on cancer cells and the specific features that determine their molecular structures are not completely elucidated. Here we report the differential cytotoxic effects of two unsubstituted ring B flavonoids that differ solely in the presence of a C2, C3 double bond in ring C, on human cancer cells of the lung (A549), pancreas (MIA PaCa-2, Panc28), colon (HCT 116, CaCo-2), Liver (HepG2), and breast (SKBr3). These compounds were extracted from Chromolaena leivensis (Hieron) a plant belonging to the genus Chromolaena reputed to have antitumor activities. 3, 5 dihydroxy-7-methoxyflavone induce apoptosis in cancer cells of the lung A549, pancreas MIA PaCa-2 and Panc28, and colon HCT116, but not on Caco-2; whereas 3,5 dihydroxy-7-methoxyflavanone display proliferative effects in A549, Panc 28, MIA PaCa, and HCT116 cells at low concentrations, and slight cytotoxicity only on CaCo-2, a cancer cell line with a higher differentiation status than other cells tested. At the concentrations studied (5-80µM) neither compound demonstrated activity against cancer cells of the liver (HepG2) or breast (SKBr3) as indicated by MTT cell viability assays. When used in combination with 3,5 dihydroxy-7-methoxyflavone in pancreatic cancer cells, the targeting preference of 3, 5 dihydroxy-7-methoxyflavanone is altered, and a significant increase in inhibition of cell viability is observed 48 hours after dosing. The presence or absence of the C2, C3 double bond in ring C, accounts for electrochemical and structural changes that dictate differential specificity towards cancer cells. 3,5 dihydroxy-7-methoxyflavone has a more planar structure, whereas the absence of the double bond in C2, C3 causes ring B to adopt a perpendicular orientation to the plane formed by rings A and C and the OH group at C3.

Pancreatic cancer (PC) remains a significant, unresolved issue because of its complex genetic blueprint and lack of reliable detection markers. The purpose of this study was to examine the possible correlation between tobacco use, gender, and age in the etiopathogenesis of PC and other cancer types with a shared-gene association (CTSG-A). The unified paradigm of cancer causation was used to understand the pathopoiesis mechanism of smoking and shared genes in PC. A cross-sectional study was performed using secondary data from the cancer survivorship module of the 2014 Behavioral Risk Factor Surveillance System survey. Results of ordinal logistic regression analyses indicated no correlation between smoking and prevalence of PC and CTSG-A, but gender and age were significant predictors. Gender has a statistically significant effect on the prediction of PC/ CTSG-A induction and promotion. Increased probability of developing the disease was found as the person reach the age between 62 and 69 years of age. Findings may enhance the understanding of environmental, genetic, and biodemographic interactions in disease evolution (induction, promotion, and expression periods). Findings may also be used to promote population health and improve health behaviors for individuals in vulnerable, high-risk groups.