Pc3-4 waves are recorded as geomagnetic pulsations with periods of 6-100s. They are generated at the bowshock and propagate to mid and auroral latitudes as Alfvén waves along closed magnetic field lines. At these latitudes Pc3-4 waves have been studied on the ground using magnetometers and in the ionosphere using HF radar. These waves have also been observed using magnetometers at polar latitudes even though there is no known propagation mechanism to the “open” field lines of the polar cap regions. In this work we used PolarDARN stations at Rankin Inlet and Inuvik to attempt the first study of Pc3-4 waves in the polar cap regions using radar. In ground scatter data, Doppler velocity oscillations with frequencies in the Pc3-4 range were found to be a common daytime occurrence. The oscillations are spatially coherent and in phase along the beam’s line of sight, matching lower latitude observations. However, upon further study it became apparent that the characteristics of the oscillations are different from those known for Pc3-4 waves. The observed oscillations have a diurnal trend that shows peaks in activity at 7:00 and 14:00MLT, where Pc3-4 oscillations have a diurnal peak at 10:30-11:00 MLT. In addition, poor coherence was observed between oscillations in radar and ground magnetic field variations at the nearby Taloyoak magnetometer. Further confounding the problem, we found that although the oscillations were coherent along the line-of-sight of the radar, poor coherence is observed when comparing oscillations in different beams separated by similar spatial scales. This finding counters both the spatial coherence observed along the beam’s line of sight and the spatial coherence of Pc3-4 waves at auroral latitudes. We conclude that it is unlikely that the observed oscillations are the result of Pc3-4 ULF waves. We instead propose that the observed Doppler velocity oscillations are caused by a change in the ionization along the ray’s path due to auroral particle precipitation.

The effects of the antidepressant mirtazapine on cytosolic Ca2+ concentrations ([Ca2+]i) in human prostate cancer PC3 cells and human osteosarcoma MG63 cells were measured by Ca2+-sensitive fluorescent probe fura-2. In Ca2+-containing medium, mirtazapine induced [Ca2+]i rises in a concentration-dependent manner in both PC3 and MG63 cells. Removal of extracellular Ca2+ inhibited the mirtazapine-induced Ca2+ signal. In Ca2+-free medium, thapsigargin (an inhibitor of the endoplasmic reticulum Ca2+-ATPase pump) induced [Ca2+]i rises by passively depleting the endoplasmic reticulum Ca2+ store, after which the increasing effect of mirtazapine (1.5 mM) on [Ca2+]i was reduced. Conversely, pretreatment with mirtazapine decreased thapsigargin-induced [Ca2+]i rises in PC3 and MG63 cells. When PC3 cells were pretreated with U73122, a phospholipase C inhibitor, mirtazapine-induced [Ca2+]i rises were inhibited by 47%. But in MG63 cells, 2 mM U73122 did not change mirtazapine-induced [Ca2+]i rises. These finding suggest that mirtazapine-induced [Ca2+]i rises were caused both by extracellular Ca2+ influx and intracellular depletion of the endoplasmic reticulum Ca2+ stores. Furthermore, the mechanism of mirtazapine-induced Ca2+ release may be different between PC3 and MG63 cells. Additionally, cell proliferation assays suggest that overnight incubation with higher concentrations of mirtazapine decreased cell viability in a concentration-dependent manner.

Prostatacancer är idag den vanligaste cancerformen i Sverige, och drygt 10 000 män årligen blir diagnosticerade med sjukdomen. En obotlig variant med dödlig utgång är kastrationsresistent prostatacancer som behandlas primärt med Docetaxel. Tumörcellerna utvecklar dock med tiden resistens mot cytostatikan, och det föreligger därför ett stort behov av att utveckla kombinationsbehandlingar med Docetaxel som grund. Mangan har i flera studier visat sig kunna inducera apoptos hos olika celltyper, och är därför intressant som ett möjligt komplement till Docetaxelbehandling. Syftet med studien var att analysera apoptos hos prostatacancerceller från cellinjen PC3 som exponerats för Docetaxel i kombination med mangan. Cellerna odlades och behandlades med Docetaxel i kombination med mangan under 24, 48 och 72 timmar. Analys av apoptos utfördes med flödescytometer efter infärgning med Annexin V och propidiumjodid. Beroende på cellernas tillstånd färgas de in i olika kombinationer och kan därmed detekteras som tidigt respektive sent apoptotiska, eller som nekrotiska. Resultaten visade på en ökning av apoptos hos kombinationsbehandlade celler, men ingen signifikant skillnad förelåg i jämförelse med obehandlade celler. Ytterligare försök bör därför upprepas med ökad koncentration av Docetaxel i kombination med olika koncentrationer av mangan, och även med andra prostatacancer cellinjer såsom DU145 och LnCaP. Dessutom bör analyser av apoptotiska markörer genomföras, i syfte att bekräfta apoptos.

Chemokines are chemotactic cytokines, which mediate cell trafficking and play a key role in mobilisation of leukocytes. More recently, chemokines and their cognate receptors have been described as key players in different aspects of cancer biology contributing to proliferation, angiogenesis and metastasis. In particular, chemokines CCL19 and CCL21 acting on their associated receptor CCR7 are postulated to be key drivers of lymph node metastasis in a number of malignancies including breast, colon, gastric, & thyroid cancers. It has been reported that the cleavage of the pre-cysteine bridge N-terminal residues of CCL21 (SDGGAQD) and of CCL19 (GTNDAED) renders both peptides incapable of fully activating CCR7. However, little is known about the nature of the interactions that occur between the N-terminal residues of CCL19 or CCL21 and the CCR7 receptor, or the role they have in activation of CCR7. The aim of this study is to investigate the role of the residues in the N-terminus of CCL19 and in particular CCL21 in the context of CCR7 activation and to use this information in the discovery of novel CCR7 antagonists or agonists. To achieve this, we synthesised a number of short (three to seven amino acids) peptides and peptidomimetics inspired by the seven N-terminal amino acid residues of CCL19 and CCL21 and pharmacologically characterised their ability to activate CCR7 or block the activation of CCR7 using a number of in vitro assays such as calcium flux, trans-well (Boyden chamber), and Western blotting. We also carried out computational studies to better understand and predict the activity of these peptides. Our results demonstrate that some of these peptides are indeed capable of acting as agonists or antagonists of CCR7. / Kuwait Health Ministry and Kuwait Civil Services Commission

Dissertationsschrift zur Erlangung eines doctor medicinae (Dr.med.) der Medizinischen Fakultät Carl Gustav Carus der Technischen Universität Dresden

Dietary supplements sold for anabolic benefits or performance enhancement often contain substances, which are nonapproved and might lack quality controls. With regard to athletes, the inclusion of substances or methods in the prohibited list of the World Anti-Doping Agency is based on medical or scientific evidence. 5α-hydroxy-laxogenin is a synthetic spirostane-type steroid, which is contained in dietary supplements and advertised as anabolic agent. To date, evidence is missing on anabolic or androgenic activity of 5α-hydroxy-laxogenin. We investigated its androgenic potential in two in vitro bioassays. While no activity was observed in the yeast androgen screen, 5α-hydroxy-laxogenin was able to trans-activate the androgen receptor in human prostate cells in a dose-dependent manner. Interestingly, a biphasic response was observed with antagonistic properties at lower concentrations and agonistic effects at higher concentrations tested. The demonstrated androgenic properties of the higher concentrations demonstrate that further investigations should focus on the safety as well as on potential anabolic effects of 5α-hydroxy-laxogenin. This is of interest with regard to abuse for doping purposes.

Background: Aspirin, the pro-drug of salicylate, is associated with reduced incidence of death from cancers and is commonly prescribed in combination with metformin in individuals with type 2 diabetes. Salicylate activates the AMP-activated protein kinase (AMPK) via Ser108 of the AMPK β1 subunit, a mechanism that is distinct from metformin, which increases AMP:ATP. Many cancers have high rates of fatty acid synthesis and AMPK inhibits this pathway through phosphorylation of acetyl-CoA carboxylase (ACC). It is unknown if targeting the AMPK-ACC-lipogenic pathway using salicylate and metformin may be effective for inhibiting cancer cell survival. Results: Salicylate suppresses clonogenic survival of prostate and lung cancer cells at therapeutic concentrations of aspirin. These clinically achievable concentrations of salicylate activated AMPK per the increasing phosphorylation of ACC and suppressing the activity of mTOR effectors kinase p70-S6 kinase and S6; effects that were enhanced with the addition of metformin and blunted in mouse embryonic fibroblasts (MEFS) deficient in AMPK β1. MEF cells deficient in AMPK β1 were more resistant to salicylates inhibitory effect on proliferation. Supplementation of media with fatty acids and mevalonate reverses the suppressive effects on cell survival indicating the inhibition of de novo lipogenesis is likely important. Conclusions: Salicylate increases ACC phosphorylation, reduces phosphorylation of mTOR targets and inhibits de novo lipogenesis in prostate and lung cancer cells, with concentrations of salicylate achievable through the ingestion of Aspirin (0.25-1.0mM) these effects are blunted in AMPK β1 deficient cells. Effects on AMPK activity via ACC phosphorylation as well as reductions in mTOR signalling targets and de novo lipogenesis are enhanced when used in combination with metformin. Suppressive effects on prostate and lung cancer cell survival are ameliorated when media is supplemented with mevalonate and fatty acids. Pre-clinical studies evaluating the use of salicylates alone and with metformin to inhibit de novo lipogenesis and the growth of prostate and lung cancers are warranted. / Thesis / Master of Science (MSc)

Deoxyhypusine synthase (DHS) catalyzes the first step in the hypusination of eukaryotic translation initiation factor 5A (eIF5A). In human cells, two eIF5A isoforms are present, eIF5A-1 and eIF5A-2, and DHS catalyzes the hypusination of both. Since both eIF5As are substrates for DHS, the biological functions of DHS are likely to be exerted through the various post-translational forms of these two eIF5As. The lysine form of eIF5A-1 has been associated with apoptosis, while the hypusinated form of eIF5A-1 has been associated with cell viability and proliferation. eIF5A-2 has been found to be over-expressed in certain cancers and has been proposed to function as an oncogene. Dhs is also over-expressed in certain human cancers and is a metastatic signature gene. The purpose of the present study was to investigate the role of DHS in cancer cell invasiveness, cell proliferation, and apoptosis using RNA interference. The main finding of the study is that DHS siRNA treatment decreases invasiveness of PC3 cells in vitro. Both DHS 0 siRNA treatment and DHS 1/b siRNA treatment significantly reduced cell invasiveness of PC3 cells as measured by the Matrigel invasion assay. Potential confounding variables, such as differences in cell proliferation or differences in apoptosis in response to DHS siRNA treatment, were assessed using the XTT cell proliferation assay and the Annexin V/Pi apoptosis assay, and they were found not to have an effect. In the absence of serum, DHS siRNA treatment did not result in significant decrease in cell proliferation compared to the control siRNA treatment. Furthermore, DHS siRNA treatment did not induce apoptosis in PC3 cells under the present experimental conditions. In conclusion, depletion of DHS with RNAi reduces invasiveness, but does not induce apoptosis in PC3 cells. The significance of the research is that the anti-invasiveness effect of DHS depletion in metastatic cancer cells is shown for the first time in the present study. Thus, DHS depletion may be useful to combat cancer in conjunction with L-eIF5A-1 over-expression.

Deoxyhypusine synthase (DHS) catalyzes the first step in the hypusination of eukaryotic translation initiation factor 5A (eIF5A). In human cells, two eIF5A isoforms are present, eIF5A-1 and eIF5A-2, and DHS catalyzes the hypusination of both. Since both eIF5As are substrates for DHS, the biological functions of DHS are likely to be exerted through the various post-translational forms of these two eIF5As. The lysine form of eIF5A-1 has been associated with apoptosis, while the hypusinated form of eIF5A-1 has been associated with cell viability and proliferation. eIF5A-2 has been found to be over-expressed in certain cancers and has been proposed to function as an oncogene. Dhs is also over-expressed in certain human cancers and is a metastatic signature gene. The purpose of the present study was to investigate the role of DHS in cancer cell invasiveness, cell proliferation, and apoptosis using RNA interference. The main finding of the study is that DHS siRNA treatment decreases invasiveness of PC3 cells in vitro. Both DHS 0 siRNA treatment and DHS 1/b siRNA treatment significantly reduced cell invasiveness of PC3 cells as measured by the Matrigel invasion assay. Potential confounding variables, such as differences in cell proliferation or differences in apoptosis in response to DHS siRNA treatment, were assessed using the XTT cell proliferation assay and the Annexin V/Pi apoptosis assay, and they were found not to have an effect. In the absence of serum, DHS siRNA treatment did not result in significant decrease in cell proliferation compared to the control siRNA treatment. Furthermore, DHS siRNA treatment did not induce apoptosis in PC3 cells under the present experimental conditions. In conclusion, depletion of DHS with RNAi reduces invasiveness, but does not induce apoptosis in PC3 cells. The significance of the research is that the anti-invasiveness effect of DHS depletion in metastatic cancer cells is shown for the first time in the present study. Thus, DHS depletion may be useful to combat cancer in conjunction with L-eIF5A-1 over-expression.

This master´s thesis discusses cytotoxicity of selected naphthoquinones on prostatic cell cultures. The introductory part is dedicated to general characteristic of naphthoquinones with focus on their cytotoxicity, testing of cytotoxicity and mechanisms of cytotoxicity. This part is followed by chapters about cytotoxicity, characteristics and biological activities of selected naphthoquinones; plumbagin and naphthazarin. The last part of this thesis’ theoretical section speaks about fluorescence microscopy and its use in research of naphthoquinones cytotoxicity. The practical part is dedicated to evaluation of cytotoxical tests’ results and to analysation of pictures of cells obtained by fluorescence microscope. At the end of thesis, all finding are summarized and put in the context.