No description available.

The overall focus of this dissertation is on how chronic shear stress alters the synthesis and secretion of important regulatory molecules by endothelial cells. Our hypothesis was that inclusion of chronic pulsatile shear stress in our model would lead to changes in endothelial cell release of regulatory molecules. We distinguished between high arterial shear stresses and low venous shear stresses and used static cell cultures as reference. The first part of this research thus entailed the complete characterization of the flow dynamics in our experimental biomechanical model. Cell stretching can have a physiological effect on endothelial cells; hence we implemented a laser based optical technique for real time strain measurement of the growth fibers used in our culture system, and found that no significant strains were occurring during shear treatment. After characterization of the mechanical environment of the cells, we focused the scope of our research on metabolism of proteoglycans and insulin-like growth factor-I (IGF-I) and related IGF binding proteins (IGFBPs) in bovine aortic endothelial cells cultured under chronic pulsatile shear. We found that shear stress increased the release of proteoglycans and significantly altered proteoglycans distribution. We also found that there was an inverse relationship between the shear level treatment used to obtain the purified proteoglycans from endothelial cells and their potency in inhibiting coagulation. IGF-I release and message (IGF-I mRNA) was decreased at high shear stress compared to low shear stress. Further, the levels found under shear were significantly greater than those observed in the static cell culture model. IGFBPs released were also significantly increased by shear. This research thus establishes a link between chronic pulsatile shear stress and the metabolism of both primary (IGF-I) and secondary (IGFBPs, proteoglycans) regulators of vascular cell activity. The improved realism of our experimental biomechanical model has proved to be a valuable tool in improving the relevance of this study to vascular research. Ultimately, this research calls for further investigation in the molecular mechanisms underlying the phenomenological effects documented, which may help in understanding fundamental aspects in cardiovascular disease and its link to hemodynamics but our work is an important first step. / Ph. D.

Le myélome multiple (MM) est caractérisé par une accumulation de plasmocytes tumoraux dans la moelle osseuse. Les cellules de MM (MMC) présentent de nombreuses anomalies cytogénétiques qui ne sont pas suffisantes pour induire la survie et la croissance de ces cellules qui sont dépendantes de l'environnement médullaire. Ce microenvironnement expriment des molécules d'adhésion et synthétisent des cytokines indispensables à la croissance du clone myélomateux. Dix principales familles de facteurs de croissance sont identifiées dans le MM (MGF) mais leur rôle respectif dans cette pathologie n'est pas établi. Ces facteurs de croissance sont produits soit par l'environnement tumoral ou soit par les cellules elle-même. La multiplicité de ces facteurs de croissance rend difficile la compréhension de la biologie du MM et l'émergence du clone tumoral in vivo. L'étude sur la coopération des 5 MGF les plus documentés nous a permis d'identifier l'IGF-1 comme un facteur de croissance majeur du MM : un inhibiteur d'IGF-1R bloque la croissance de 7/8 lignées de MM (HMCL) et la boucle autocrine de l'IGF-1 essentielle à l'activité de croissance de l'IL-6, d'HB-EGF et d'HGF. De plus, nous avons identifié que la présence d'IGF-1R (présent dans 44% des MMC) était un facteur de mauvais pronostic. L'IL-6 qui est le deuxième MGF majeur induit la croissance de 7/8 lignées. L'IL-6R, exprimé dans toutes les MMC, est aussi un facteur de mauvais pronostic quand il a une fortement exprimé dans les MMC de patients. Par la suite, nous avons étudié l'effet de l'insuline, cytokine de forte homologie avec l'IGF-1. Nous avons montré que l'insuline avait le même effet que l'IGF-1. Son activité nécessite l'activation d'IGF-1R qui est transduit par la présence du récepteur hétérodimère IGF-1R/INSR (hybrid-R) à la surface des MMC. L'insuline ne pouvant pas activer l'homodimère IGF-1R à des concentrations physiologiques, ce qui montre que l'hybrid-R confère à l'insuline la capacité à activer l'IGF-1R donc de devenir un MGF. Un inhibiteur ciblant l'IGF-1R mais également l'Hybrid-R en association avec un anti-IL-6 semblerait donc être un traitement prometteur dans la pathologie du MM pour les 44% des patients exprimant l'IGF-1R.

Common measures of egg quality have been survival to specific developmental stages, higher hatching rate of fertilized eggs and final production of fry. Determinants of egg quality are variable among and between teleost species and no common unified criteria have been established. Maternally inherited genes influence egg quality and early embryo development is partially programmed by the messenger ribonucleic acid (mRNA). Among the genes, the insulin family is important for growth functions and the presence of their transcripts in the ovary, oocytes and embryos implies their involvement during the reproductive process and their relevance to egg quality. The insulin-like growth factor (IGF) system has three components, the ligands IGF-I and II, the IGFBPs (insulin-like growth factor binding proteins) and the IGF receptors that mediate biological activity of the ligands. Vitellogenin (Vtg) is the major source of nutrients for the developing embryo and elevated levels in female fish plasma signals gonadal development preceding spawning. In oviparous fish where the developing embryo is dependent on the stored food in the yolk, vitellogenin levels in the egg could indicate its capability to support embryonic growth. This study aimed to develop molecular tools, specifically probes for IGF-I, IGF-II and IGF-IR, for the evaluation of fish egg quality. These probes would be used to determine expression levels of IGF-I, IGF-II and IGF-IR during egg development to assess their potential as molecular indicators for egg quality. In addition, this study also aimed to establish an enzyme-linked immunoassay (ELISA) for quantifying Vtg in fish eggs and determine if differences in Vtg levels could be linked to fertilization and hatching success. Through reverse-transcription polymerase chain reaction (RT-PCR) putative complementary deoxyribonucleic acid (cDNA) fragments of IGF-I, IGF-II and IGF-IR were cloned and sequenced from mullet (Mugil cephalus) and grouper (Epinephelus coioides). The relative expression ratio of the three genes in the eggs of mullet and grouper were assayed by quantitative PCR (QPCR) and calculated using the Pfaffl method (Pfaffl, 2001). Levels of vitellogenin in different batches of mullet eggs were quantified by ELISA. Spawned eggs of grouper were grouped into low (<60%) or high (>60%) fertilization rate (FR) and the fertilized eggs that were incubated until hatching were grouped into medium (>90%) or high (>90%) hatching rate (HR). Samples were categorized into sinking eggs, late embryo and hatched larvae. Relative expression ratio of IGF-II was significantly high (P<0.01) compared to IGF-I and IGF-IR in all samples examined. All three genes were strongly expressed in sinking eggs compared to either late embryo or hatched larvae. However, there was no significant interaction effect between the genes and the samples analyzed. Mullet samples all came from a high FR and high HR group and were categorized into sinking, multicell stage, blastula, gastrula, late embryo and hatched larvae. There was a significant interaction effect (P<0.01) between gene and stage, showing that genes are differentially expressed during embryonic development. IGF-II was strongly expressed relative to the other genes in all stages examined and was highest during the gastrula stage. Vtg levels were examined in mullet oocytes and egg samples that were grouped into 4; oocytes from females that subsequently spawned, had fertilized eggs which hatched (Group A); oocytes from females that did not spawn, therefore no fertilization and no hatching (Group B); eggs that were stripped, artificially fertilized but no hatching (Group C); and eggs that were spawned, assumed to be fertilized but did not hatch (Group D). Group A showed a trend of higher Vtg levels than the other three but this result was not statistically significant.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第19399号 / 医博第4050号 / 新制||医||1012(附属図書館) / 32424 / 京都大学大学院医学研究科医学専攻 / (主査)教授 長船 健二, 教授 川口 義弥, 教授 小川 誠司 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Bone metastases are a frequent clinical complication associated with cancer. The aim of this PhD thesis was to set up a model system for the study of tumour cell – bone cell interactions in vitro, ex vivo and in vivo and to use this system to test the efficacy of a novel therapeutic agent for the treatment of osteolytic bone disease. Co-culture or conditioned medium studies using human or mouse cancer cell lines were used to develop an in vitro model system of tumour cell – bone cell interactions. This showed that osteolytic tumour cells enhance osteoclast formation, fusion and resorption through the production of various factors that act directly on osteoclasts and their precursors. And in addition, that osteolytic tumour cells also enhance osteoclastogenesis indirectly via increasing the production of RANKL in osteoblasts. Other effects on osteoblasts included reductions in differentiation, migration and adhesion. Successful ex vivo and in vivo models for the study of tumour – induced osteolysis were created using adapted organ cultures and intratibial injection techniques respectively. IGF-1 and its receptor are known to play important roles in both bone metabolism and breast cancer. Therefore a study of the effects of IGF-1 receptor inhibition on tumour cell – bone cell interactions was performed. In vitro studies showed that the novel IGF-1 receptor tyrosine kinase inhibitor PQIP significantly inhibited IGF-1 and breast cancer enhanced osteoclast formation. Western blot analysis suggested this may be due to the inhibition of both IGF-1 and cancer conditioned medium induced PI3k/Akt activation. Moreover, treatment of osteoblasts with PQIP inhibited cancer cell conditioned medium induced increases in RANKL production. Ex vivo studies using human MDA-MB-231 – mouse calvarial organ co-cultures demonstrated that MDA-MB-231 cells caused osteolysis and this was completely prevented by PQIP without affecting cancer cell viability. Furthermore, once daily oral administration of PQIP significantly decreased trabecular bone loss and reduced the size of osteolytic bone lesions following mouse 4T1 breast cancer cell intratibial injection in mice. Quantitative histomorphometry showed a significant reduction in breast cancer-induced osteoclast number and activity. Consistent with the significant inhibition of osteoblast differentiation, spreading, migration and bone nodule formation observed in vitro, PQIP also inhibited osteoblast number and bone formation in vivo. No inhibition of in vivo tumour volume was observed. These findings clearly suggest that oral PQIP treatment reduced the rate of cancer associated bone turnover. In conclusion, this thesis successfully demonstrates a model system for investigating tumour cell-bone cell interactions in vitro, ex vivo and in vivo. Using this model system I showed that pharmacologic inhibition of IGF-1 receptor kinase activity using PQIP inhibits osteoclast and osteoblast changes induced by breast cancer cells in vitro and in vivo and prevents osteolysis ex vivo and in vivo. This indicates that PQIP and its novel derivatives which are now in advanced clinical development may be of value in the treatment of osteolytic bone disease associated with breast cancer.

No description available.

Cancer develops in many organs and tissues in the body through genetic and environmental modifications to acquire the hallmarks of cancer. The hallmarks of cancer allow the cells to become malignant and progress to a tumorigenic state. It has previously been shown in various carcinomas that HIF-2a, a key component in hypoxia adaptation, has a role in autonomous growth, the first hallmark of cancer. Ovarian cancer is the most lethal of the gynecological malignancies and accounts for 3% of new cases in women annually but is the fifth most common cause of death due to cancer. Here, it is shown in two ovarian carcinoma cell lines that HIF-2a is involved in in vitro and in vivo growth. It is also shown that the effect of HIF-2a is due to its role in autonomous growth and not vascularization with the use of in vitro spheroids. From recent findings in the laboratory the oxygen-stimulated translation initiation complex was discovered and HIF-2a is one of its components. In the absence of HIF-2a there is a downregulation in translation in hypoxia in ovarian carcinoma. This is also seen in a HIF-2a translational target, IGF1R and its downstream signaling pathway, which may be involved in autonomous growth as well as other hallmarks of cancer. Taken together, the data in this thesis presents the importance of HIF-2a in autonomous growth and cancer progression in ovarian carcinoma, as well as verifying its role in translation.

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The general aims of the thesis were to study GH responsiveness by estimation of pharmacokinetics and bioavailability of injected recombinant human GH (rhGH), of growth response as gain in heightSDS during childhood and puberty, and IGF-I response as change in circulating IGF-ISDS and IGFBP3SDS. Methods Short children were recruited during 1988–1999 into two national randomized multicentre clinical trials on growth until adult height. A group of 117 GHD patients who had been treated from prepuberty with a single GH dose of 33μg/kg/day for at least 1 year were randomized at onset of puberty either to remain on this dose regimen or to an increased dose, GH67μg/kg/day, administered once daily or divided into two doses, GH33x2μg/kg/day. Data on IGF-ISDS and IGF binding protein 3 (IGFBP3)SDS were available from 111 patients and analysed as stated below. The 151 short prepubertal non-GHD patients were randomized into three groups: untreated controls, GH33 or GH67μg/kg/day. A subpopulation from both trials, 128 patients examined annually in Gothenburg, formed the study sample on GH uptake. They received sc GH injections to obtain 16–24 hour GH curves and the GH pharmacokinetics and bioavailability was calculated. Results: A dose-dependent effect on Cmax was found with great intra- and inter-individual variability. Of the Cmax variability, 43% was explained by the rhGH dose and proxies for injection depth. Median bioavailability of the injected dose was 71%, with great variation, mainly dependent on injection depth. In the IGHD group a dose-dependent difference in pubertal gain in heightSDS was found, with mean of 0.8 for the GH67 group and 0.4 for GH33, p&lt;0.01. The mean total gain in heightSDS during treatment was 1.9 for GH67 and 1.4 for GH33, p&lt;0.01. A dose-dependent pubertal ΔIGF-ISDS was 0.5 vs −0.1, p=0.007, correlating to pubertal gain in heightSDS, p=0.003; and was the most important variable to explain the variation in pubertal gain in heightSDS. In the non-GHD group the ΔIGF-ISDS from baseline to mean study level was dose-dependent 2.07 vs 1.20, p=0.001; and correlated negatively with baseline values of IGF-ISDS, rho= -0.56 for GH67, p=0.001, vs rho= -0.82 for GH33, p=0.0001, and correlated positively with gain in heightSDS in both GH-treated groups, rho= 0.42, p&lt;0.001. In multivariable regression analyses, ΔIGF-ISDS was always an important explanatory variable for long-term growth response from the prepubertal period until adult height, while the IGF-ISDS study level per se was not. Conclusion: Growth response to GH treatment was dose dependent with great variability between patients. More pubertal growth was attained by an increased rhGH dose, mimicking the physiology of healthy children, in whom GH secretion rate increases during puberty. This resulted in a gain in IGF-ISDS closely correlating to pubertal gain in heightSDS in both IGHD and non-GHD patients. A broad range in GH responsiveness was found for both growth and IGF response in both diagnostic groups, but lower in the non-GHD group. Higher uptake of a given GH dose was observed after a deep injection and a higher GH concentration. These results are clinically applicable for individuals who remain short close to onset of puberty; by identifying and deeply injecting a rhGH dose that accounts for individual responsiveness, we can stimulate an increment in IGF-ISDS that correlates to gain in heightSDS during puberty.