Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 5 uppsatser.

Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (leaves 91-124).

Thesis (Ph.D.) -- University of Texas Southwestern Medical Center at Dallas, 2005. / Campus access only. Vita. Bibliography: 176-188.

Self-renewing, chemoresistant cancer cells that contribute to cancer metastasis and patient relapse have properties similar to those of stem cells, and have been termed "cancer stem cells" (CSCs) in the literature. The identification of signaling pathways that regulate CSC development and/or function is an important step towards understanding why patients relapse, and towards development of novel therapeutics that specifically target CSC vulnerabilities. Recent studies have identified a role for the aryl hydrocarbon receptor (AHR), an environmental carcinogen receptor implicated in cancer initiation, in normal tissue-specific stem cell self-renewal. These studies inspired the hypothesis that the AHR plays a role in CSC development. To test this hypothesis, AHR activity in Hs578T triple negative and SUM149 inflammatory breast cancer cells was modulated with AHR ligands, shRNA, or AHR-specific inhibitors and their phenotypic, genomic, and functional CSC characteristics were evaluated. Aldehyde dehydrogenase (ALDH) was used as an epithelial stem cell marker for flow cytometry. Results demonstrate that: 1) ALDHhigh cells express elevated levels of Ahr and the AHR-driven gene that encodes cytochrome p450 isoform 1b1 (Cyp1b1), 2) AHR knockdown reduces ALDH activity, 3) AHR hyper-activation significantly increases ALDH1 activity, expression of stem cell- and invasion/migration-associated genes, and accelerates cell migration, 4) a highly significant correlation between Ahr or Cyp1b1 expression (as a surrogate marker for AHR activity) and expression of the CSC- and invasion/migration-associated gene sets was seen with genomic data obtained from 79 human breast cancer cell lines and over 1850 primary human breast cancers, 5) the AHR interacts directly with the transcription factors Sox2 and Runx1, and AHR ligands increase this interaction, 6) AHR knockdown inhibits tumorsphere formation in low adherence conditions, 7) AHR inhibition blocks the rapid migration of ALDHhigh cells and reduces ALDHhigh cell chemoresistance, and 8) AHR knockdown inhibits tumor growth and reduces tumor Aldh1a1, Sox2, and Cyp1b1 expression in orthotopic xenografts. These data suggest that the AHR plays an important role in development of CSCs in a large fraction of human breast cancers and that environmental AHR ligands may exacerbate breast cancer by enhancing expression of CSC-like properties.

Cancer and thrombosis are common co-occurrences in healthcare today. Cancer is the second leading cause of death in the United States with thrombosis being the second leading killer of cancer patients behind tumor progression. Cancer patients as a whole are 4 to 7 times more likely to develop thrombosis and 20%-30% of all first-time thrombosis diagnoses are cancer-related. Risk assessment and treatment options have much room for improvement. The lack of success for conventional antithrombotic prophylaxis suggests that hyperthrombosis in cancer works through a discrete pathway. A discovery by our group in recent years correlated the increased activity of Aryl hydrocarbon receptor (AHR) in the body to increase thrombotic phenotypes in patients with chronic kidney disease. Another group had published a manuscript about Kynurenine (Kyn), an activating ligand of the receptor that was produced by tumor cells to promote tumor growth through an AHR pathway (Opitz 2011). The link between the findings of these two groups could show that Kyn—AHR pathway is causing the increase in thrombosis in cancer patients. We used an animal model of thrombosis in cancer and created a new variation of it to test the Kyn—AHR pathway. We hypothesized that cancerous animals would show an increase in thrombosis and increased levels of AHR and Kyn along with downstream elements such as Tissue Factor (TF). Cancer was induced on nude mice via xenograft injection of cancer cells and 4-5 weeks of incubation to allow the tumors to proliferate. After the incubation period, mice underwent inferior vena cava (IVC) ligation, and were then euthanized 48 hours later. Two types of cancer were tested: HT-29 colon adenocarcinoma and A549 non small cell lung adenocarcinoma. There were 4 animal groups: mice that were injected with cancer cells and operated on, mice that were injected with cancer cells but not operated on, mice that were not injected but were operated on, and mice that did not receive neither the injections or the operation. After euthanasia, blood, tumors, and major organs were harvested to assess markers and pathways of thrombosis associated with cancer. We were able to successfully grow xenograft tumors in the nude mice. The HT-29 tumors grew very aggressively while A549 tumors experienced a small latent period before starting to proliferate. Animals with HT-29 and A549 xenograft tumors displayed greater thrombosis, measured by the weight of the blood clot formed in the IVC due to ligation (p=0.04 and p=0.05, respectively). HT-29 also displayed significant increases in Kyn, AHR activity, indoxyl sulfate (IS), and showed increased staining of tissue factor with immunohistochemistry. A549 did not have significant p-values in these experiments, but did show upward trends in all categories besides IS sera levels. In summary, we developed a new animal model of thrombosis in colon adenocarcinoma and showed significant increases in thrombosis as well as multiple markers of thrombosis. This is an exciting and complex way to study thrombosis in cancer in an in vivo approach with opportunities for future therapeutic testing. / 2020-07-03T00:00:00Z

Le cancer constitue l’une des principales causes de mortalité, plus particulièrement dans l’ensemble des pays développés, et représente, de ce fait aujourd’hui un problème de santé publique majeur.Depuis quelques années, les alcaloïdes marins représentent une source d’inspiration importante pour les chimistes en vue d’obtenir de nouveaux médicaments anticancéreux.Dans cette optique, des recherches effectuées au sein de notre laboratoire ont fait état de la synthèse d’analogues de ces alcaloïdes possédant une structure tris aromatique.Nous avons développé une approche synthétique originale de ces composés disposant d’un hétérocycle central sur lequel sont greffés deux noyaux phényles ou indoles substitués avec des groupes hydroxy ou hydrophiles. Ils sont reliés entre eux par une liaison carbone-carbone ou carbone-amine ce qui a généré une bibliothèque de près de 150 molécules originales.Différentes évaluations pharmacologiques ont été réalisées. L’inhibition des kinases (DYRK1A, CDK5, GSK3) par nos produits et l’évaluation de leur cytotoxicité sur diverses lignées cellulaires cancéreuses humaines ont été réalisées.L’obtention de ces composés a été également l’occasion de nous intéresser à la synthèse et la réactivité du 2-indolyltrifluoroborate de potassium dans les réactions de Suzuki-Miyaura. Un travail méthodologique a été réalisé dans ce sens. / Cancer, one of the leading causes of death, particularly in the developed countries, represents today a major public health problem.Over the last few years, marine alkaloids represent a source of inspiration for chemists in order to obtain new anticancer drogs.For this purpose, as a part of our laboratory researches, analogues of marine alkaloids were synthesized possessing a tris-aromatic structure.We developed an original approach to synthesize these compounds formed by a central heterocycle core on wich is graft two arylic or indoles patterns with hydroxylic or hydrophilic side chains. They are related by a carbon-carbon or carbon-amine bond that generated a library of 150 original molecules.Various pharmacological analyses were carried out. The inhibition of kinases (DYRK1A, CDK5, GSK3) by our products and the evaluation of their cytotoxicity on various human cancer cell lines have been performed.Obtaining these compounds was also an opportunity to be interested in the synthesis and reactivity of potassium 2-indolyl trifluoroborate towards Suzuki-Miyaura reaction. A new methodology was developed.

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The main goal of this thesis was to develop new methods and knowledge that will explain and predict species differences in sensitivity to dioxin-like compounds (DLCs) in birds. The important achievements and results obtained from the four experimental chapters of this thesis are summarized as follow: (1) an efficient luciferase reporter gene (LRG) assay was developed for use with 96-well cell culture plates; (2) the results obtained from LRG assay were shown to be highly correlated to available in ovo toxicity data; (3) amino acids at positions 324 and 380 within the aryl hydrocarbon receptor 1 ligand binding domain (AHR1 LBD) were shown to be responsible for reduced Japanese quail (Coturnix japonica) AHR1 activity to induce a dioxin-responsive reporter gene in comparison to chicken (Gallus gallus domesticus), and ring-necked pheasant (Phasianus colchicus) AHR1 in response to different DLCs; (4) AHR1 LBD sequences of 86 avian species were studied and differences at amino acid sites 256, 257, 297, 324, 337 and 380 were identified. It was discovered that only positions 324 and 380 play a role in AHR1 activity to induce a dioxin-responsive gene; (5) in COS-7 cells expressing chicken AHR1, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) are equipotent inducers of the reporter gene and bind with similar affinity to chicken AHR1, however, in the cells expressing pheasant, Japanese quail and common tern (Sterna hirundo) AHR1, PeCDF is a stronger inducer than TCDD. PeCDF also binds with higher affinity to pheasant and quail AHR1 than TCDD. The results of this thesis show that embryo lethal effect of DLCs in avian species can be predicted by use of two new non-lethal methods: (1) the LRG assay and (2) determination of the identity of the amino acids at positions 324 and 380. The findings and methods described in this thesis will be of use for environmental risk assessments of DLCs.