SIRT1 and SIRT2 are two NAD⁺-dependent deacetylases which negatively modulate the activity of p53, a protein which is involved in cell cycle arrest, senescence and apoptosis following genotoxic stress. Part I of the thesis describes the exploration of the chemical space around a reported unselective and modest inhibitor of SIRT1 and SIRT2 with the aim of improving the selectivity and potency of the inhibitor against the two isoforms. Particular emphasis is placed upon understanding the mode of binding of the novel analogues within the active site of the enzymes. Chapter 1 reviews the physiological roles of class III NAD⁺-dependent deacetylases, also known as sirtuins. In particular, the application of SIRT1 and SIRT2 inhibitors as potential anticancer agents is described. Amongst these, only cambinol and the tenovins showed in vivo activity in a mouse xenograft model. Previously only one analogue of cambinol had been reported in the literature. Chapter 2 describes the development of a small collection of novel cambinol analogues (First Generation Studies). The role played by different substituents at the phenyl group and at the N-1 of the thiouracil core is discussed. Along with the synthesis and structure activity relationship (SAR) associated with the core structure, in-cell experiments intended to confirm the activity of the most active compounds are reported. Chapter 3 provides a rationalisation for the SAR discussed in Chapter 2. Based on computational molecular modelling studies (GOLD), the activity of the most potent and selective SIRT2 inhibitors is explained. Two series of novel cambinol analogues were designed (Second and Third Generation Analogues) in order to assess further the proposed binding mode. Chapter 4 focuses on the development of the “Second Generation” analogues, characterised by the presence of lipophilic substituents at the sulfur atom and at the N-3 position of the thiouracil core. The synthesis, biological evaluation and SAR are discussed in detail. Chapter 5 reports the development of the “Third Generation” analogues, characterised by either a benzyl group or para-alkoxy-substituted benzyl group at the N-1 position of cambinol. Once again, the synthesis, biological evaluation and SAR data are presented. An improved understanding of the mode of binding of the novel compounds is proposed based on molecular dynamics (MD) studies. Indole-based alkaloids, such as Vincristine and Vinblastine, are well known for their anticancer activity. Recently, the anticancer activity of members of the calycanthaceous family of alkaloids has been discovered. Part II of the thesis focuses on model studies aimed at developing the total synthesis of one of these compounds, perophoramidine. Chapter 7 provides an overview of the calycanthaceous alkaloid family of natural products, including their biological properties. The structural features of perophoramidine, along with the previously reported synthetic studies are outlined. Chapter 8 describes the synthesis of an advanced intermediate in the total synthesis of dehaloperophoramidine, a structural analogue of perophoramidine Problems encountered, optimisation studies and the synthesis of a re-designed intermediate are also reported in this chapter.

Yau Mei-sze. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 96-112). / Abstracts in English and Chinese. / Abstract / Abstract (Chinese Version) / Acknowledgements / List of Abbreviations / Table of Contents / List of Tables / List of Figures / Chapter Chapter 1 --- Introduction / Chapter Chapter 2 --- Literature Review / Chapter 2.1 --- Hepatocellular Carcinoma / Chapter 2.2 --- Epidermal Growth Factor Receptor / Chapter 2.2.1 --- Activation of Epidermal Growth Factor Receptor / Chapter 2.2.2 --- Epidermal Growth Factor Receptor Signaling Pathways / Chapter 2.2.3 --- Expression Level and Patient Survival / Chapter 2.2.4 --- Epidermal Growth Factor Receptor Activity and Tumor Cell Growth / Chapter 2.2.5 --- Epidermal Growth Factor Receptor Activity and Radiation / Chapter 2.3 --- "Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor, ZD1839" / Chapter 2.3.1 --- Tumor Cell Growth Control Activities of ZD1839 / Chapter 2.3.2 --- Factors Affecting the Tumor Cell Growth Control Activities of ZD1839 / Chapter 2.3.3 --- Radiosensitization Activities of ZD1839 / Chapter 2.3.4 --- Factors Affecting the Radiosensitization Activities of ZD1839 / Chapter 2.4 --- Study Objectives / Chapter Chapter 3 --- Materials and Methods / Chapter 3.1 --- ZD1839 / Chapter 3.2 --- Cell lines and Cell Culture / Chapter 3.3 --- Immunoblot Analysis / Chapter 3.3.1 --- Total Protein Extraction / Chapter 3.3.2 --- Protein Amount Determination / Chapter 3.3.3 --- Protein Separation / Chapter 3.3.4 --- Blotting / Chapter 3.3.5 --- Antibody Labeling / Chapter 3.3.6 --- Detection of Antibody Binding / Chapter 3.4 --- Cytotoxicity Assay / Chapter 3.5 --- Nucleotide sequence analysis / Chapter 3.5.1 --- Total RNA Extraction / Chapter 3.5.2 --- RNA Amount Determination / Chapter 3.5.3 --- Reverse Transcription - Polymerase Chain Reaction (RT-PCR) / Chapter 3.5.3.1 --- Reverse Transcription / Chapter 3.5.3.2 --- High Fidelity Polymerase Chain Reaction / Chapter 3.5.4 --- Purification of PCR Product / Chapter 3.5.5 --- Cycle Sequencing Reaction / Chapter 3.5.6 --- DNA Precipitation and Sequencing / Chapter 3.6 --- Clonogenic Assay / Chapter 3.7 --- Immunohistochemical Analysis / Chapter Chapter 4 --- Results / Chapter 4.1 --- Immunoblot Analysis / Chapter 4.2 --- Cytotoxicity Assay / Chapter 4.2.1 --- Effect of ZD 1839 on cell morphology / Chapter 4.2.2 --- Effect of ZD 1839 on cell growth / Chapter 4.3 --- Nucleotide sequence analysis / Chapter 4.3.1 --- RNA Concentration of HCC cells / Chapter 4.3.2 --- Sequencing of TK domain within EGFR / Chapter 4.3.3 --- Sequencing of TK domain within HER2 / Chapter 4.4 --- Clonogenic assay / Chapter 4.4.1 --- Effects of ZD 1839 pre-treatment on radiation response / Chapter 4.4.2 --- Effects of ZD 1839 continuous treatment on radiation response / Chapter 4.5 --- Immunohistochemical Analysis / Chapter Chapter 5 --- Discussion / Chapter 5.1 --- Important Findings / Chapter 5.2 --- EGFR Expression of HCC Cells / Chapter 5.3 --- Cytotoxicity of ZD1839 on HCC Cell Lines / Chapter 5.4 --- Factors Affecting the Cytotoxicity of ZD1839 / Chapter 5.4.1 --- Effect of EGFR Expression on ZD1839 Cytotoxicity / Chapter 5.4.2 --- Effect of EGFR Mutations on ZD 1839 Cytotoxicity / Chapter 5.4.3 --- Effect of HER2 Expression on ZD1839 Cytotoxicity / Chapter 5.4.4 --- Effect of HER2 Mutations on ZD 1839 Cytotoxicity / Chapter 5.5 --- Radiation Response ofHCC Cell Lines upon ZD1839 Treatment / Chapter 5.6 --- Factors Affecting Radiation Response of ZD1839-treated HCC Cell Lines / Chapter 5.6.1 --- Effect of Growth Arrest on Radiation Response of HCC Cell Lines / Chapter 5.6.2 --- Other Factors Affecting Radiation Response of HCC Cell Lines / Chapter Chapter 6 --- Conclusion / References

Tse, Sui Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 95-104). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.v / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.1.1 --- Basic Concepts and Definitions --- p.2 / Chapter 1.2 --- Evolutionary Algorithms --- p.5 / Chapter 1.2.1 --- Chromosome Encoding --- p.6 / Chapter 1.2.2 --- Selection --- p.7 / Chapter 1.2.3 --- Crossover --- p.9 / Chapter 1.2.4 --- Mutation --- p.10 / Chapter 1.2.5 --- Elitism --- p.11 / Chapter 1.2.6 --- Niching --- p.11 / Chapter 1.2.7 --- Population Manipulation --- p.13 / Chapter 1.2.8 --- Building Blocks --- p.13 / Chapter 1.2.9 --- Termination Conditions --- p.14 / Chapter 1.2.10 --- Co-evolution --- p.14 / Chapter 1.3 --- Local Search --- p.15 / Chapter 1.4 --- Memetic Algorithms --- p.16 / Chapter 1.5 --- Objective --- p.17 / Chapter 1.6 --- Summary --- p.17 / Chapter 2 --- Background --- p.18 / Chapter 2.1 --- Multiple Drugs Tumor Chemotherapy --- p.18 / Chapter 2.2 --- Bioinformatics --- p.22 / Chapter 2.2.1 --- Basics of Bioinformatics --- p.24 / Chapter 2.2.2 --- Applications on Biomedical Systems --- p.26 / Chapter 3 --- A New Drug Administration Dynamic Model --- p.29 / Chapter 3.1 --- Three Drugs Mathematical Model --- p.31 / Chapter 3.1.1 --- Rate of Change of Different Subpopulations --- p.32 / Chapter 3.1.2 --- Rate of Change of Different Drug Concen- trations --- p.35 / Chapter 3.1.3 --- Toxicity Effects --- p.35 / Chapter 3.1.4 --- Summary --- p.36 / Chapter 4 --- Memetic Algorithm - Iterative Dynamic Program- ming (MA-IDP) --- p.38 / Chapter 4.1 --- Problem Formulation: Optimal Control Problem (OCP) for Mutlidrug Optimization --- p.38 / Chapter 4.2 --- Proposed Memetic Optimization Algorithm --- p.40 / Chapter 4.2.1 --- Iterative Dynamic Programming (IDP) . . --- p.40 / Chapter 4.2.2 --- Adaptive Elitist-population-based Genetic Algorithm (AEGA) --- p.44 / Chapter 4.2.3 --- Memetic Algorithm 一 Iterative Dynamic Programming (MA-IDP) --- p.50 / Chapter 4.3 --- Summary --- p.56 / Chapter 5 --- MA-IDP: Experiments and Results --- p.57 / Chapter 5.1 --- Experiment Settings --- p.57 / Chapter 5.2 --- Optimization Results --- p.61 / Chapter 5.3 --- Extension to Other Mutlidrug Scheduling Model . --- p.62 / Chapter 5.4 --- Summary --- p.65 / Chapter 6 --- DNA Sequencing by Hybridization (SBH) --- p.66 / Chapter 6.1 --- Problem Formulation: Reconstructing a DNA Sequence from Hybridization Data --- p.70 / Chapter 6.2 --- Proposed Memetic Optimization Algorithm --- p.71 / Chapter 6.2.1 --- Chromosome Encoding --- p.71 / Chapter 6.2.2 --- Fitness Function --- p.73 / Chapter 6.2.3 --- Crossover --- p.74 / Chapter 6.2.4 --- Hill Climbing Local Search for Sequencing by Hybridization --- p.76 / Chapter 6.2.5 --- Elitism and Diversity --- p.79 / Chapter 6.2.6 --- Outline of Algorithm: MA-HC-SBH --- p.81 / Chapter 6.3 --- Summary --- p.82 / Chapter 7 --- DNA Sequencing by Hybridization (SBH): Experiments and Results --- p.83 / Chapter 7.1 --- Experiment Settings --- p.83 / Chapter 7.2 --- Experiment Results --- p.85 / Chapter 7.3 --- Summary --- p.89 / Chapter 8 --- Conclusion --- p.90 / Chapter 8.1 --- Multiple Drugs Cancer Chemotherapy Schedule Optimization --- p.90 / Chapter 8.2 --- Use of the MA-IDP --- p.91 / Chapter 8.3 --- DNA Sequencing by Hybridization (SBH) --- p.92 / Chapter 8.4 --- Use of the MA-HC-SBH --- p.92 / Chapter 8.5 --- Future Work --- p.93 / Chapter 8.6 --- Item Learned --- p.93 / Chapter 8.7 --- Papers Published --- p.94 / Bibliography --- p.95

Additionally, we showed that SeC induced S-phase arrest in MCF-7 cells associated with a marked decrease in the protein expression of cyclin A, D1 and D3 and cyclin-dependent kinases (CDK) 4 and 6, with concomitant induction of p21waf1/Cip1, p27Kip1 and p53. Expose of MCF-7 cells to SeC resulted in delayed onset of apoptosis as evidenced by caspase activation, PARP cleavage and DNA fragmentation. SeC treatment also triggered the activation of JNK, p38 MAPK, ERK and Akt phosphorylation. Inhibitors of ERK (U0126) or Akt (LY294002), but not JNK (SP600125) and p38 MAPK (SB203580), significantly suppressed SeC-induced S-phase arrest and apoptosis in MCF-7 cells. In conclusion, our findings establish a mechanistic link between the PI3K/Akt pathway, MAPK pathway and SeC-induced cell cycle arrest and apoptosis in human breast cancer cells. (Abstract shortened by UMI.) / The role of selenium as potential cancer chemopreventive and chemotherapeutic agents has been supported by epidemiological, preclinical and clinical studies. Although cell apoptosis has been evidenced as a critical mechanism mediating the anticancer activity of selenium, the underlying molecular mechanisms remain elusive. In the present study, selenocystine (SeC), a novel organic selenocompound, is identified as a novel antiproliferative agent with a broad spectrum of inhibition against eight human cancer cell lines with the IC50 values ranged from 3.6 to 37.0 muM. Despite this potency, SeC was relatively nontoxic toward HS68 human fibroblasts with an IC 50 value exceeded 400 muM. Further investigation on the molecular mechanisms indicated that SeC induced caspase-independent apoptosis in MCF-7 breast carcinoma cells, which was accompanied by poly(ADP-ribose) polymerase (PARP) cleavage, caspase activation, DNA fragmentation, phosphatidylserine exposure and nuclear condensation. Moreover, SeC induced the loss of mitochondrial membrane potential (DeltaPsim) by regulating the expression and phosphorylation of pro-surivival and pro-apoptotic Bcl-2 family members. Loss of DeltaPsim led to the mitochondrial release of cytochrome c and apoptosis-inducing factor (AIF) which subsequently translocated into the nucleus and induced chromatin condensation and DNA fragmentation. MCF-7 cells exposed to SeC shown increase in total p53 and phosphorylated p53 on serine residues of Ser15, Ser20, and Ser392 prior to mitochondrial dysfunction. Silencing and attenuation of p53 expression with RNA interference and pifithrin-alpha treatment respectively, partially suppressed SeC-induced cell apoptosis. Furthermore, generation of reactive oxygen species (ROS) and subsequent induction of DNA strand breaks were found to be upstream cellular events induced by SeC. The thiol-reducing antioxidants, N-acetylcysteine and glutathione, completely blocked the initiation and execution of cell apoptosis. Taken together, these results suggest that SeC, as a promising anticancer selenocompound, induces caspase-independent apoptosis in MCF-7 cells mediated by ROS generation and p53 phosphorylation through regulating the mitochondrial membrane permeability. / Chen, Tianfeng. / Adviser: Yun-Shing Wong. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3260. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 124-136). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

A breast cancer cell line stably transfected with the CYP19 gene had been employed for aromatase inhibition. Among the phytochemicals tested, the major dietary flavonoids, such as genistein and daidzein, produced very weak inhibition. On the other hand, the red clover isoflavone biochanin A, the hydroxychalcone butein and the red grape phytoalexin resveratrol were found to be effective aromatase inhibitors. Cell proliferation assay had shown that they could inhibit ER-positive cell proliferation induced by testosterone, and the inhibitory effect was specifically attributed to the reduction of estrogen synthesis. In another breast cancer cell line SK-BR-3, resveratrol, biochanin A and genistein inhibited CYP19 both in enzyme and promoter I.3/II transcriptional levels. The element responsible for the inhibition of aromatase by these phytoestrogens should fall within the region between -556 to -446 by upstream of exon II. / Breast cancer is one of the most common cancers affecting women. Estrogen plays an important role in breast cancer initiation and development. The majority of breast tumors are initially dependent upon estrogen to support their growth. Most breast cancers occur in the postmenopausal period. However, the intra-tumoral estradiol (E2) is maintained at a high level equivalent to the pre-menopausal status. High intra-tumoral E2 level in postmenopausal women is sustained by the biosynthesis of estrogens in the tumorous tissue. / Genistein and Biochanin A, ranged from 0.1 to 10 muM, might act as estrogen agonist and induced aromatase activity and promoter I.1 transactivation in ERalpha-transfected SK-BR-3 cells. (Abstract shortened by UMI.) / The aromatase enzyme, CYP19, belongs to a family of P450 enzyme. As a final rate-limiting step in estrogen biosynthesis, it catalyzes the conversion of C 19 steroids to estrogens. The expression of CYP19 is tissue-specific, and is regulated by alternate promoter usage. The use of aromatase inhibitors for breast cancer treatment has become a major therapeutic approach. / The consumption of some phytochemicals protects against breast cancer. Yet the mechanisms are far from clear. In my present study, various phytochemicals, including phytoestrogens, monoterpenes and carotenoids, were evaluated for their effect on aromatase. / Wang Yun. / "July 2005." / Adviser: Lai-Kwok Leung. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3716. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 145-169). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

Colorectal cancer is the second leading cause of cancer-related mortality in Hong Kong and lack of selectivity has limited the success of conventional chemotherapy. Given the recent interest in the anti-cancer effects of traditional Chinese medicine (TCM), there are two approaches to studying its bioactivity: as a mixture of ingredients or as single compounds. The objective of the present study is to examine the anti-tumor effects of Angelicae Sinensis Radix (DG) and Garcinia hanburyi resin (TH) using both approaches, respectively, as they are traditionally used to treat inflammation. In the present study, their anti-cancer effects and the mechanisms of actions were examined for the development of potential novel chemotherapeutic drugs for colon cancer since inflammation is a predisposing factor for colon cancer. / DG extract and its three main bioactive phtbalides: n-butylidenephthalide, senkyunolide A and z-ligustilide (LGT), were found to be cytotoxic to HT-29 cells with IC50 values (24 h) of 20.70 +/- 0.85, 72.51 +/- 8.65, 18.74 +/- 1.14 and 41.98 +/- 3.64 mug/ml, respectively. The results evidenced that LGT induced G0/G 1 arrest and apoptosis, triggering cleavage of PARP, pro-caspases-3, -8 and -9 and nuclear fragmentation. LGT and cisplatin synergistically reduced the viability of HT-29 cells. More interestingly, DG extract was more potent than individual phthalides, suggesting that there are other bioactive components and/or synergistic interactions. / Individual compounds purified from TH were investigated because gambogic acid isolated from this herb has been used clinically to treat cancer, 30-Epicambogin (EPC) and guttiferone K (GUTK) showed the highest cytotoxic selectivity and potency on HT-29 cells among 15 isolated compounds. IC50 values (24 h) for EPC and GUTK in HT-29 cells were 5.36+/-0.25 and 5.39+/-0.22 muM, respectively, and both induced G0/G1 arrest by down-regulation of cyclins D1, D3, CDK4 and CDK6, while up-regulation of p21Waf1/CiP1 and p27KiP1. Both compounds triggered the activation of caspases-3, -8 and -9 in apoptosis. The in vivo anti-tumor effects of GUTK were further investigated by using a subcutaneous Colon-26 mouse tumor model. GUTK (10 mg/kg i.p.) reduced tumor volume by 33.6% and potentiated the anti-tumor effects of 5-fluorouracil when administered concurrently. / Our findings revealed that DG rather than individual phthalides, is worthy for further study as a potential anti-cancer drug, due to the synergistic interactions among multi-components in the herb. On the other hand, EPC and GUTK, isolated from TH have potential to be developed as novel anti-tumor candidates for combination use with 5-fluorouracil. The results strongly support the use of different approaches to study TCM for chemotherapy, according to its traditional and empirical use. / Subsequently, the anti-proliferative effects of DG and Chuanxiong Rhizoma (CX) extracts and mixtures containing three phthalides in the proportions similar to their presence in both extracts were examined, since CX also contains the same phthalides, but in different proportions. DG extract was significantly more potent than its corresponding phthalide mixture to inhibit cancer cell proliferation and synergistic interaction was observed among the phthalides and other bioactive components, while the phthalides in CX extract interacted antagonistically with other components. / Kan, Lai Ting Winnie. / Adviser: Ge Lin. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 267-311). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Colorectal cancer (CRC) is a major public health problem worldwide. Despite improvements in the diagnostic process and advancement in the treatment methods, the prognosis remains poor. To improve survival rates, it is important to identify people with the predisposition for CRC and to detect the potentially curable early stage of the disease. Furthermore, identifying those who would have an adverse clinical outcome associated with a particular chemotherapy would help to avoid redundant chemotherapy burden in patients and contribute to enhanced therapeutic efficacy, while minimizing treatment-related toxicity. The aim of the Thesis was to search for novel promising diagnostic, prognostic and predictive DNA-based biomarkers of sporadic form of CRC. As each patient is genetically unique, these biomarkers would aid clinicians in better diagnosis and/or in the selection of an optimal type of therapy for an individual CRC patient based on their molecular profile. In order to explore this issue, we investigated several candidate genes in healthy individuals as well as in newly diagnosed cancer patients. The major outcomes of this PhD study, which were fully reported in seven publications included in the present Thesis, are 1) The observation of several candidate single nucleotide polymorphisms in microRNA...

Indiana University-Purdue University Indianapolis (IUPUI) / The time course and biological mechanisms by which breast cancer (BC) and/or alterations in estrogen status lead to cognitive and brain changes remain unclear. The studies presented here use neuroimaging, cognitive testing, genetics, and biomarkers to investigate how post-chemotherapy interval (PCI), chemotherapy-induced amenorrhea (CIA), and genetic variation in the estrogen pathway affect the brain. Chapter 1 examines the association of post-chemotherapy interval (PCI) with gray matter density (GMD) and working memory-related brain activation in BC survivors (mean PCI 6.4, range 3-10 years). PCI was positively associated with GMD and activation in the right frontal lobe, and GMD in this region was correlated with global neuropsychological function. In regions where BC survivors showed decreased GMD compared to controls, this was inversely related to oxidative DNA damage and learning and memory scores. This is the first study to show neural effects of PCI and relate DNA damage to brain alterations in BC survivors. Chapter 2 demonstrates prospectively, in an independent cohort, decreased combined magnitudes of brain activation and deactivation from pre-to post-chemotherapy in patients undergoing CIA compared to both postmenopausal BC patients undergoing chemotherapy and healthy controls. CIA’s change in activity magnitude was strongly correlated with change in processing speed, suggesting this activity increase reflects effective cognitive compensation. These results demonstrate that the pattern of change in brain activity from pre- to post-chemotherapy varies according to pre-treatment menopausal status. Chapter 3 presents the effects of variation in ESR1, the gene that codes for estrogen receptor-α, on brain structure in healthy older adults. ESR1 variation was associated with hippocampus and amygdala volumes, particularly in females. Single nucleotide polymorphism (SNP) rs9340799 influenced cortical GMD and thickness differentially by gender. Apolipoprotein E (APOE)-ε4 carrier status modulated the effect of SNP rs2234693 on amygdala volumes in women. This study showed that genetic variation in estrogen relates to brain morphology in ways that differ by sex, brain region and APOE-ε4 carrier status. The three studies presented here explore the interplay of BC, estrogen, and cognition, showing that PCI, CIA, and ESR1 genotype influence brain phenotypes. Cognitive correlates of neuroimaging findings indicate potential clinical significance of these results.

Parmi les tumeurs cérébrales primaires, les gliomes sont les tumeurs les plus fréquemment rencontrées. Les glioblastomes (GBM) représentent 60 à 70% de ces tumeurs et malgré de récents progrès dans leur traitement, leur pronostic reste sombre. Les gliomes malins sont caractérisés par une prolifération cellulaire importante, un taux élevé de néo-angiogenèse et une migration diffuse des cellules tumorales gliales dans le parenchyme cérébral, ce qui rend impossible une résection chirurgicale complète. De plus, les cellules gliales tumorales migrantes opposent une résistance particulière aux traitements chimiothérapiques de type pro-apoptotique, causant une récidive quasi inévitable de ce type de tumeur. La compréhension des aspects moléculaires à la base de la prolifération, de la migration et de la chimiorésitance des cellules gliales tumorales est donc essentielle pour élaborer des approches ciblées capables d’entraver ces processus. La littérature mentionne plusieurs stratégies qui permettraient, en théorie, de court-circuiter la résistance à l’apoptose des cellules tumorales gliales migrantes. Il s’agirait entre autres :<p>- de réduire le taux d’activation des voies de signalisation contrôlées par PI3K /Akt /mTOR et NFkappaB, qui diminuerait le taux de croissance des gliomes malins, ainsi que le taux de migration des cellules tumorales isolées dans le parenchyme cérébral;<p>- de réduire le taux de migration des cellules tumorales gliales afin de restaurer un certain degré de sensibilité à des agents chimiothérapiques pro-apoptotiques;<p>- d’endiguer l’export des agents chimiothérapiques par les pompes à efflux surexprimées dans les gliomes <p>- d'induire d’autres processus de mort cellulaire que l’apoptose, car les cellules tumorales gliales migrantes sont plus sensibles à d’autres formes de mort cellulaire.<p>Ces besoins de nouvelles stratégies thérapeutiques ont motivé ce travail qui se focalisera sur le potentiel antitumoral des ligands du R-sigma1 dans les glioblastomes. Ainsi, nous montrerons que les ligands des Rs-sigma sont capables de produire certains des effets visés dans les stratégies ci-dessus, dont la réduction de la prolifération et de la migration des cellules cancéreuses avec une certaine potentialisation des chimiothérapies. Ces propriétés ouvrent de nouvelles perspectives en thérapie anticancéreuse pour cette famille de ligands, dont plusieurs membres sont déjà utilisés depuis de nombreuses années comme antipsychotique. / Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished

Indiana University-Purdue University Indianapolis (IUPUI) / Signal transducer and activator of transcription 3 (STAT3) is constitutively activated in malignant tumors, and its activation is associated with high histological grade and advanced cancer stage. STAT3 has been shown to play important roles in multiple aspects of cancer aggressiveness including proliferation, survival, self-renewal, migration, invasion, angiogenesis and immune response by regulating the expression of diverse downstream target genes. Thus, inhibiting STAT3 promises to be an attractive strategy for treatment of advanced tumors with metastatic potential. We firstly identified a STAT3 inhibitor, inS3-54, by targeting the DNA-binding site of STAT3 using an in-silico screening approach; however, inS3-54 was finally found not to be appropriate for further studies because of low specificity on STAT3 and poor absorption in mice. To develop an effective and specific STAT3 inhibitor, we identified 89 analogues for the structure-activity relationship analysis. By using hematopoietic progenitor cells isolated from wild-type and STAT3 conditional knockout mice, further studies showed that three analogues (A18, A26 and A69) only inhibited STAT3-dependent colony formation of hematopoietic progenitor cells, indicating a higher selectivity for STAT3 than their parental compound, inS3-54. These compounds were found to (1) inhibit STAT3-specific DNA binding activity; (2) bind to STAT3 protein; (3) suppress proliferation of cancer cells harboring aberrant STAT3 signaling; (4) inhibit migration and invasion of cancer cells and (5) inhibit STAT3-dependent expression of downstream targets by blocking the binding of STAT3 to the promoter regions of responsive genes in cells. In addition, A18 can reduce tumor growth in a mouse xenograft model of lung cancer with little effect on body weight. Taken together, we conclude that it is feasible to inhibit STAT3 by targeting its DNA-binding domain for discovery of anticancer therapeutics.