| 1. |
- Senkowski, Wojciech
(författare)
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High-throughput screening using multicellular tumor spheroids to reveal and exploit tumor-specific vulnerabilities
- 2017
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Doktorsavhandling (övrigt vetenskapligt)abstract
- High-throughput drug screening (HTS) in live cells is often a vital part of the preclinical anticancer drug discovery process. So far, two-dimensional (2D) monolayer cell cultures have been the most prevalent model in HTS endeavors. However, 2D cell cultures often fail to recapitulate the complex microenvironments of in vivo tumors. Monolayer cultures are highly proliferative and generally do not contain quiescent cells, thought to be one of the main reasons for the anticancer therapy failure in clinic. Thus, there is a need for in vitro cellular models that would increase predictive value of preclinical research results. The utilization of more complex three-dimensional (3D) cell cultures, such as multicellular tumor spheroids (MCTS), which contain both proliferating and quiescent cells, has therefore been proposed. However, difficult handling and high costs still pose significant hurdles for application of MCTS for HTS.In this work, we aimed to develop novel assays to apply MCTS for HTS and drug evaluation. We also set out to identify cellular processes that could be targeted to selectively eradicate quiescent cancer cells. In Paper I, we developed a novel MCTS-based HTS assay and found that nutrient-deprived and hypoxic cancer cells are selectively vulnerable to treatment with inhibitors of mitochondrial oxidative phosphorylation (OXPHOS). We also identified nitazoxanide, an FDA-approved anthelmintic agent, to act as an OXPHOS inhibitor and to potentiate the effects of standard chemotherapy in vivo. Subsequently, in Paper II we applied the high-throughput gene-expression profiling method for MCTS-based drug screening. This led to discovery that quiescent cells up-regulate the mevalonate pathway upon OXPHOS inhibition and that the combination of OXPHOS inhibitors and mevalonate pathway inhibitors (statins) results in synergistic toxicity in this cell population. In Paper III, we developed a novel spheroid-based drug combination-screening platform and identified a set of molecules that synergize with nitazoxanide to eradicate quiescent cancer cells. Finally, in Paper IV, we applied our MCTS-based methods to evaluate the effects of phosphodiesterase (PDE) inhibitors in PDE3A-expressing cell lines.In summary, this work illustrates how MCTS-based HTS yields potential to reveal and exploit previously unrecognized tumor-specific vulnerabilities. It also underscores the importance of cell culture conditions in preclinical drug discovery endeavors.
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| 2. |
- Magnusson, Marie, et al.
(författare)
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A placebo-controlled study of retinal blood flow changes by pentoxifylline and metabolites in humans
- 2006
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Ingår i: British Journal of Clinical Pharmacology. - : Wiley. - 0306-5251 .- 1365-2125. ; 61:2, s. 138-147
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To investigate the possible effects of pentoxifylline metabolites on retinal blood flow in humans. METHODS: A randomized, placebo-controlled, four-period cross-over study that was observer blinded and partly blinded for the eight participants. On one occasion a placebo was given as an intravenous (i.v.) infusion over 100 min. On the other three occasions pentoxifylline was administered as i.v. infusions over 100 min at a rate of 3 mg min(-1). Before two of the pentoxifylline infusions the subjects were pretreated with either ciprofloxacin or rifampicin. Retinal blood flow was measured by scanning laser doppler flowmetry (SLDF) in a selected area of the central temporal retina before, during and until 5 h after the end of infusion. Blood samples for concentration analyses of pentoxifyllin, R-M1, S-M1, M4 and M5 were taken serially and areas under the curves (AUCs) were calculated. Linear mixed models were used for the statistical analyses. RESULTS: Mean AUCs (ng h ml(-1)) were significantly increased for pentoxifylline (1964 vs. 1453) and S-M1 (5804 vs. 4227), but not R-M1 when pentoxifylline was co-administered with ciprofloxacin. The mean AUC for M5 was significantly reduced when subjects were pretreated with rifampicin (2041 vs. 3080). Pentoxifylline with and without pretreatment with rifampicin significantly increased retinal blood flow assessed as mean flow, pulsation (i.e. 1-systole/diastole), and diastolic flow (but not during systole), compared with placebo. The increases over placebo were more pronounced on diastolic flow, 9.7% (95% confidence interval 4.2, 15.5) than on mean flow, 4.6% (1.1, 8.3) after pentoxifylline administration. With pentoxifylline after rifampicin pretreatment the corresponding differences were 11.7% (5.8, 17.9) and 5.1% (1.4, 7.8) over placebo, respectively. After co-administration of pentoxifylline and ciprofloxacin we saw only a nonsignificant trend towards increased flow during diastole, but a significant decrease in pulsation. When AUCs for pentoxifylline and its metabolites were used as regressor variables to retinal mean flow we found that pentoxifylline, R-M1 and M5 had coefficients with a positive sign indicating that they enhanced the retinal blood flow. In contrast, S-M1 and M4 had coefficients with negative sign and thus appeared to decrease the blood flow in subjects treated with pentoxifylline. CONCLUSION: The R-M1 and M5 metabolites of pentoxifylline contributed significantly to the effects of pentoxifylline on retinal blood flow.
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| 3. |
- Saulo, Eleonor C., et al.
(författare)
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Willingness and ability to pay for artemisinin-based combination therapy in rural Tanzania
- 2008
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Ingår i: Malaria Journal. - London : BioMed Central. - 1475-2875 .- 1475-2875. ; 7, s. 227-
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to analyse willingness to pay (WTP) and ability to pay (ATP) for ACT for children below five years of age in a rural setting in Tanzania before the introduction of artemisinin-based combination therapy (ACT) as first-line treatment for uncomplicated malaria. Socio-economic factors associated with WTP and expectations on anti-malaria drugs, including ACT, were also explored.MethodsStructured interviews and focus group discussions were held with mothers, household heads, health-care workers and village leaders in Ishozi, Gera and Ishunju wards in north-west Tanzania in 2004. Contingent valuation method (CVM) was used with "take-it-or-leave-it" as the eliciting method, expressed as WTP for a full course of ACT for a child and households' opportunity cost of ACT was used to assess ATP. The study included descriptive analyses with multivariate adjustment for potential confounding factors.ResultsAmong 265 mothers and household heads, 244 (92%, CI = 88%–95%) were willing to pay Tanzanian Shillings (TSh) 500 (US$ 0.46) for a child's dose of ACT, but only 55% (49%–61%) were willing to pay more than TSh 500. Mothers were more often willing to pay than male household heads (adjusted odds ratio = 2.1, CI = 1.2–3.6). Socio-economic status had no significant effect on WTP. The median annual non-subsidized ACT cost for clinical malaria episodes in an average household was calculated as US$ 6.0, which would represent 0.9% of the average total consumption expenditures as estimated from official data in 2001. The cost of non-subsidized ACT represented 7.0% of reported total annual expenditure on food and 33.0% of total annual expenditure on health care."Rapid effect," "no adverse effect" and "inexpensive" were the most desired features of an anti-malarial drug.ConclusionWTP for ACT in this study was less than its real cost and a subsidy is, therefore, needed to enable its equitable affordability. The decision taken in Tanzania to subsidize Coartem® fully at governmental health care facilities and at a consumer price of TSh 300–500 (US$ 0.28–0.46) at special designated shops through the programme of Accredited Drug Dispensing Outlets (ADDOs) appears to be well founded.
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| 4. |
- Liu, Yawei, et al.
(författare)
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Neuron-mediated generation of regulatory T cells from encephalitogenic T cells suppresses EAE.
- 2006
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Ingår i: Nature Medicine. - : Nature Publishing Group. - 1546-170X .- 1078-8956. ; 12:5, s. 518-525
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Tidskriftsartikel (refereegranskat)abstract
- Neurons have been neglected as cells with a major immune-regulatory function because they do not express major histocompatibility complex class II. Our data show that neurons are highly immune regulatory, having a crucial role in governing T-cell response and central nervous system (CNS) inflammation. Neurons induce the proliferation of activated CD4+ T cells through B7-CD28 and transforming growth factor (TGF)-beta1–TGF-beta receptor signaling pathways, resulting in amplification of T-cell receptor signaling through phosphorylated ZAP-70, interleukin (IL)-2 and IL-9. The interaction between neurons and T cells results in the conversion of encephalitogenic T cells to CD25+TGF-beta1+CTLA-4+FoxP3+ T regulatory (Treg) cells that suppress encephalitogenic T cells and inhibit experimental autoimmune encephalomyelitis. Suppression is dependent on cytotoxic T lymphocyte antigen (CTLA)-4 but not TGF-beta1. Autocrine action of TGF-beta1, however, is important for the proliferative arrest of Treg cells. Blocking the B7 and TGF-beta pathways prevents the CNS-specific generation of Treg cells. These findings show that generation of neuron-dependent Treg cells in the CNS is instrumental in regulating CNS inflammation.
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| 5. |
- Xu, Bo, 1980-
(författare)
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Evolutionary and Pharmacological Studies of NPY and QRFP Receptors
- 2014
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Doktorsavhandling (övrigt vetenskapligt)abstract
- The neuropeptide Y (NPY) system consists of 3-4 peptides and 4-7 receptors in vertebrates. It has powerful effects on appetite regulation and is involved in many other biological processes including blood pressure regulation, bone formation and anxiety. This thesis describes studies of the evolution of the NPY system by comparison of several vertebrate species and structural studies of the human Y2 receptor, which reduces appetite, to identify amino acid residues involved in peptide-receptor interactions.The NPY system was studied in zebrafish (Danio rerio), western clawed frog (Xenopus tropicalis), and sea lamprey (Petromyzon marinus). The receptors were cloned and functionally expressed and their pharmacological profiles were determined using the native peptides in either binding studies or a signal transduction assay. Some peptide-receptor preferences were observed, indicating functional specialization.A receptor family closely related to the NPY receptors, called the QRFP receptors, was investigated. A QRFP receptor was cloned from amphioxus, Branchistoma floridae, showing that the receptor arose before the origin of the vertebrates. Evolutionary studies demonstrated that the ancestral vertebrate had as many as four QRFP receptors, only one of which remains in mammals today. This correlates with the NPY receptor family, located in the same chromosomal regions, which had seven members in the ancestral vertebrate but only 4-5 in living mammals. Some vertebrates have considerably more complex NPY and QRFP receptor systems than humans and other mammals.Two studies investigated interactions of NPY-family peptides with the human Y2 receptor. Candidate residues, selected based on structural modeling and docking, were mutated to disrupt possible interactions with peptide ligands. The modified receptors were expressed in cultured cells and investigated by measuring binding and functional responses. Several receptor residues were found to influence peptide-receptor interactions, some of which are involved in maintaining receptor structure. In a pilot study, the kinetics of peptide-receptor interaction were found to be very slow, of the order several hours.In conclusion, this thesis clarifies evolutionary relationships for the complex NPY and QRFP peptide-receptor systems and improves the structural models of the human NPY-family receptors, especially Y2. These results will hopefully facilitate drug design for targeting of NPY-family receptors.
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| 6. |
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| 7. |
- Lai, Kuei-Hung
(författare)
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Studies on anti-leukemic terpenoids from medicinal mushrooms and marine sponges with ChemGPS-NP-based targets investigation of lead compounds
- 2017
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Doktorsavhandling (övrigt vetenskapligt)abstract
- This thesis investigates the anti-leukemic activity of terpenoids isolated from medicinal mushrooms and marine sponges, as well as their possible targets and mechanisms of action.In the first section, we focused on studying the triterpenoidal components of three triterpenoid-enriched medicinal mushrooms Antrodia cinnamomea, Ganoderma lucidum, and Poria cocos, which have been used in folk medicine for centuries and also developed into several contemporary marketed products. We isolated the major and characteristic triterpenoids from these mushrooms, together with six new lanostanoids (II-1–II-6). The anti-leukemic activity of the isolates was evaluated in vitro using MTT proliferative assay and seven of them exhibited potential anti-leukemic effect. The active lead compounds were further subjected to computational analyses utilizing the ChemGPS-NP tool. We established a database for the anti-leukemic relevant chemical space of triterpenoids isolated from these three medicinal mushrooms, which could be used as a reference database for further research on anti-leukemic triterpenoids. Our results indicated that the anti-leukemic effect of the active lead compounds was mediated not only through topoisomerases inhibition but also through inhibiting DNA polymerases.The second and third sections focused on isolation of anti-leukemic sesterterpenoids from sponges. The investigation of Carteriospongia sp. led to the isolation of two new scalarane-type sesterterpenoids (III-1 and III-2) and one known tetraprenyltoluquinol-related metabolite (III-3). All isolates exhibit an apoptotic mechanism of action against Molt 4 cells, found to be mediated through the disruption of the mitochondrial membrane potential (MMP) and inhibition of topoisomerase IIα expression. Detailed investigation of the apoptotic mechanism of action using molecular docking analysis revealed that compound III-1 might target Hsp90 protein. The apoptotic-inducing effect of III-3 was supported by in vivo experiment by suppressing the volume of xenograft tumor growth (47.58%) compared with the control.In the final section of this thesis we studied manoalide and its derivatives, sesterterpenoids isolated from the sponge Luffariella sp.. Manoalide has been studied as a potential anti-inflammatory agent for the last thirty years with more than 200 publications and 40 patents. However, the configurations at positions 24 and 25 were never revealed. In the current study, ten manoalide-type sesterterpenoids (IV-1–IV-10) were isolated from Luffariella sp. and their stereoisomers at positions 24 and 25 were identified and separated for the first time. The configuration at positions 24 and 25 showed to have a significant effect on the anti-leukemic activity of manoalide derivatives, with the 24R,25S-isomer exhibiting the most potent anti-leukemic activity. The apoptotic mechanism of action of compound IV-7 against Molt 4 cells was investigated, and the compound was found to trigger MMP disruption and intracellular reactive oxygen species (ROS) generation. Compound IV-7 also inhibited activity against both human topoisomerases, I and II. The in vivo experiment further supported the anti-leukemic effect of IV-7 with a 66.11% tumor volume suppression compared to the control.
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| 8. |
- Ekman, Elisabet, et al.
(författare)
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Awareness among nurses about reporting of adverse drug reactions in Sweden
- 2012
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Ingår i: Drug, Healthcare and Patient Safety. - : Dove Medical Press Ltd.. - 1179-1365 .- 1179-1365. ; 4, s. 61-66
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Tidskriftsartikel (refereegranskat)abstract
- Background: The purpose of this study was to investigate awareness among nurses regarding their new role as reporters of adverse drug reactions in Sweden and factors that may influence reporting by nurses.Methods: In 2007, all nurses were included in the adverse drug reaction reporting scheme in Sweden. A questionnaire was sent to 753 randomly selected nurses in September 2010.Results: Of the 453 (60%) responding nurses, 265 (58%) were aware that nurses were included in the reporting of adverse drug reactions. Sixty-one nurses (14%) stated that they had reported an adverse drug reaction. Fifteen percent (n = 70) of the respondents had received training about reporting of adverse drug reactions. Almost one third of these (n = 21, 30%) had reported an adverse drug reaction on at least one occasion. Among nurses without training, a smaller proportion (n = 40, 11%, P < 0.05) had reported an adverse drug reaction on at least one occasion. The two factors considered most important by nurses for reporting were the severity of the adverse drug reaction and if the reaction was to a newly approved drug. A majority of the nurses (n = 397, 88%) were interested in a training course in pharmacology as part of their ongoing professional development. One third (32%) of all nurses stated that one reason for not reporting a suspected adverse drug reaction was that the physician responsible did not regard the reaction necessary to report.Conclusion: We found that more than half of the study population of nurses in Sweden were aware of their new role as reporters of adverse drug reactions, but few of the responding nurses had reported an adverse drug reaction. Given that training seems to be associated with high reporting frequency, we suggest more training in pharmacovigilance for nurses.
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| 9. |
- Jurcevic, Sanja, 1971-, et al.
(författare)
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Bioinformatics analysis of miRNAs in the neuroblastoma 11q-deleted region reveals a role of miR-548l in both 11q-deleted and MYCN amplified tumour cells
- 2022
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Neuroblastoma is a childhood tumour that is responsible for approximately 15% of all childhood cancer deaths. Neuroblastoma tumours with amplification of the oncogene MYCN are aggressive, however, another aggressive subgroup without MYCN amplification also exists; rather, they have a deleted region at chromosome arm 11q. Twenty-six miRNAs are located within the breakpoint region of chromosome 11q and have been checked for a possible involvement in development of neuroblastoma due to the genomic alteration. Target genes of these miRNAs are involved in pathways associated with cancer, including proliferation, apoptosis and DNA repair. We could show that miR-548l found within the 11q region is downregulated in neuroblastoma cell lines with 11q deletion or MYCN amplification. In addition, we showed that the restoration of miR-548l level in a neuroblastoma cell line led to a decreased proliferation of these cells as well as a decrease in the percentage of cells in the S phase. We also found that miR-548l overexpression suppressed cell viability and promoted apoptosis, while miR-548l knockdown promoted cell viability and inhibited apoptosis in neuroblastoma cells. Our results indicate that 11q-deleted neuroblastoma and MYCN amplified neuroblastoma coalesce by downregulating miR-548l.
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| 10. |
- Bhandage, Amol K., 1988-
(författare)
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Glutamate and GABA signalling components in the human brain and in immune cells
- 2016
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Doktorsavhandling (övrigt vetenskapligt)abstract
- Glutamate and γ-aminobutyric acid (GABA) are the principal excitatory and inhibitory neurotransmitters in the central nervous system (CNS). They both can activate their ionotropic and metabotropic receptors. Glutamate activates ionotropic glutamate receptors (iGlu - AMPA, kainate and NMDA receptors) and GABA activates GABA-A receptors which are modulated by many types of drugs and substances including alcohol. Using real time quantitative polymerase chain reaction, I have shown that iGlu and/or GABA-A receptor subunits were expressed in the hippocampus dentate gyrus (HDG), orbitofrontal cortex (OFC), dorsolateral prefrontal cortex (DL-PFC), central amygdala (CeA), caudate and putamen of the human brain and their expression was altered by chronic excessive alcohol consumption. It indicates that excitatory and inhibitory neurotransmission may have been altered in the brain of human alcoholics. It is possible that changes in one type of neurotransmitter system may drive changes in another. These brain regions also play a role in brain reward system. Any changes in them may lead to changes in the normal brain functions.Apart from the CNS, glutamate and GABA are also present in the blood and can be synthesised by pancreatic islet cells and immune cells. They may act as immunomodulators of circulating immune cells and can affect immune function through glutamate and GABA receptors. I found that T cells from human, rat and mouse lymph nodes expressed the mRNAs and proteins for specific GABA-A receptor subunits. GABA-evoked transient and tonic currents recorded using the patch clamp technique demonstrate the functional GABA-A channel in T cells. Furthermore, the mRNAs for specific iGlu, GABA-A and GABA-B receptor subunits and chloride cotransporters were detected in peripheral blood mononuclear cells (PBMCs) from men, non-pregnant women, healthy and depressed pregnant women. The results indicate that the expression of iGlu, GABA-A and GABA-B receptors is related to gender, pregnancy and mental health and support the notion that glutamate and GABA receptors may modulate immune function. Intra- and interspecies variability exists in the expression and it is further influenced by physiological conditions.
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