| 1. |
- Lundström, Erik, 1964-, et al.
(författare)
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Effects of Fluoxetine on Outcomes at 12 Months After Acute Stroke Results From EFFECTS, a Randomized Controlled Trial
- 2021
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Ingår i: Stroke. - : Ovid Technologies (Wolters Kluwer Health). - 0039-2499 .- 1524-4628. ; 52:10, s. 3082-3087
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: The EFFECTS (Efficacy of Fluoxetine-a Randomised Controlled Trial in Stroke) recently reported that 20 mg fluoxetine once daily for 6 months after acute stroke did not improve functional outcome but reduced depression and increased fractures and hyponatremia at 6 months. The purpose of this predefined secondary analysis was to identify if any effects of fluoxetine were maintained or delayed over 12 months. METHODS: EFFECTS was an investigator-led, randomized, placebo-controlled, double-blind, parallel group trial in Sweden that enrolled adult patients with stroke. Patients were randomized to 20 mg oral fluoxetine or matching placebo for 6 months and followed for another 6 months. The primary outcome was functional outcome (modified Rankin Scale), at 6 months. Predefined secondary outcomes for these analyses included the modified Rankin Scale, health status, quality of life, fatigue, mood, and depression at 12 months. RESULTS: One thousand five hundred patients were recruited from 35 centers in Sweden between 2014 and 2019; 750 were allocated fluoxetine and 750 placebo. At 12 months, modified Rankin Scale data were available in 715 (95%) patients allocated fluoxetine and 712 (95%) placebo. The distribution of modified Rankin Scale categories was similar in the 2 groups (adjusted common odds ratio, 0.92 [95% CI, 0.76-1.10]). Patients allocated fluoxetine scored worse on memory with a median value of 89 (interquartile range, 75-100) versus 93 (interquartile range, 82-100); P=0.0021 and communication 93 (interquartile range, 82-100) versus 96 (interquartile range, 86-100); P=0.024 domains of the Stroke Impact Scale compared with placebo. There were no other differences in secondary outcomes. CONCLUSIONS: Fluoxetine after acute stroke had no effect on functional outcome at 12 months. Patients allocated fluoxetine scored worse on memory and communication on the Stroke Impact Scale compared with placebo, but this is likely to be due to chance.
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| 2. |
- Lundström, Erik, Docent, 1964-, et al.
(författare)
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Update on the EFFECTS study of fluoxetine for stroke recovery: a randomised controlled trial in Sweden
- 2020
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Ingår i: Trials. - Uppsala : Springer Science and Business Media LLC. - 1745-6215. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- Studies have suggested that fluoxetine might improve neurological recovery after stroke, but the results remain inconclusive. The EFFECTS (Efficacy oF Fluoxetine - a randomisEd Controlled Trial in Stroke) reached its recruitment target of 1500 patients in June 2019. The purpose of this article is to present all amendments to the protocol and describe how we formed the EFFECTS trial collaboration in Sweden. Methods In this investigator-led, multicentre, parallel-group, randomised, placebo-controlled trial, we enrolled non-depressed stroke patients aged 18 years or older between 2 and 15 days after stroke onset. The patients had a clinical diagnosis of stroke (ischaemic or intracerebral haemorrhage) with persisting focal neurological deficits. Patients were randomised to fluoxetine 20 mg or matching placebo capsules once daily for 6 months. Results Seven amendments were made and included clarification of drug interaction between fluoxetine and metoprolol and the use of metoprolol for severe heart failure as an exclusion criterion, inclusion of data from central Swedish registries and the Swedish Stroke Register, changes in informed consent from patients, and clarification of design of some sub-studies. EFFECTS recruited 1500 patients at 35 centres in Sweden between 20 October 2014 and 28 June 2019. We plan to unblind the data in January 2020 and report the primary outcome in May 2020. Conclusion EFFECTS will provide data on the safety and efficacy of 6 months of treatment with fluoxetine after stroke in a Swedish health system setting. The data from EFFECTS will also contribute to an individual patient data meta-analysis.
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| 3. |
- Abdissa, Negera, et al.
(författare)
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Cytotoxic Quinones from the roots of Aloe dawei
- 2014
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Ingår i: Molecules. - : MDPI AG. - 1420-3049 .- 1431-5157. ; 19:3, s. 3264-3273
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Tidskriftsartikel (refereegranskat)abstract
- Seven naphthoquinones and nine anthraquinones were isolated from the roots of Aloe dawei by chromatographic separation. The purified metabolites were identified by NMR and MS analyses. Out of the sixteen quinones, 6-hydroxy-3,5-dimethoxy-2-methyl-1,4-naphthoquinone is a new compound. Two of the isolates, 5,8-dihydroxy-3-methoxy-2-methylnaphthalene-1,4-dione and 1-hydroxy-8-methoxy-3-methylanthraquinone showed high cytotoxic activity (IC50 1.15 and 4.85 µM) on MCF-7 breast cancer cells, whereas the others showed moderate to low cytotoxic activity against MDA-MB-231 (ER Negative) and MCF-7 (ER Positive) cancer cells.
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| 4. |
- Abrhámová, Kateřina, et al.
(författare)
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Truncating the spliceosomal 'rope protein' Prp45 results in Htz1 dependent phenotypes.
- 2024
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Ingår i: RNA Biology. - 1547-6286 .- 1555-8584. ; 21:1, s. 1-17
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Tidskriftsartikel (refereegranskat)abstract
- Spliceosome assembly contributes an important but incompletely understood aspect of splicing regulation. Prp45 is a yeast splicing factor which runs as an extended fold through the spliceosome, and which may be important for bringing its components together. We performed a whole genome analysis of the genetic interaction network of the truncated allele of PRP45 (prp45(1-169)) using synthetic genetic array technology and found chromatin remodellers and modifiers as an enriched category. In agreement with related studies, H2A.Z-encoding HTZ1, and the components of SWR1, INO80, and SAGA complexes represented prominent interactors, with htz1 conferring the strongest growth defect. Because the truncation of Prp45 disproportionately affected low copy number transcripts of intron-containing genes, we prepared strains carrying intronless versions of SRB2, VPS75, or HRB1, the most affected cases with transcription-related function. Intron removal from SRB2, but not from the other genes, partly repaired some but not all the growth phenotypes identified in the genetic screen. The interaction of prp45(1-169) and htz1Δ was detectable even in cells with SRB2 intron deleted (srb2Δi). The less truncated variant, prp45(1-330), had a synthetic growth defect with htz1Δ at 16°C, which also persisted in the srb2Δi background. Moreover, htz1Δ enhanced prp45(1-330) dependent pre-mRNA hyper-accumulation of both high and low efficiency splicers, genes ECM33 and COF1, respectively. We conclude that while the expression defects of low expression intron-containing genes contribute to the genetic interactome of prp45(1-169), the genetic interactions between prp45 and htz1 alleles demonstrate the sensitivity of spliceosome assembly, delayed in prp45(1-169), to the chromatin environment.
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| 5. |
- Alalam, Hanna, et al.
(författare)
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A Genetic Trap in Yeast for Inhibitors of SARS-CoV-2 Main Protease
- 2021
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Ingår i: MSYSTEMS. - 2379-5077. ; 6:6
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Tidskriftsartikel (refereegranskat)abstract
- The ongoing COVID-19 pandemic urges searches for antiviral agents that can block infection or ameliorate its symptoms. Using dissimilar search strategies for new antivirals will improve our overall chances of finding effective treatments. Here, we have established an experimental platform for screening of small molecule inhibitors of the SARS-CoV-2 main protease in Saccharomyces cerevisiae cells, genetically engineered to enhance cellular uptake of small molecules in the environment. The system consists of a fusion of the Escherichia coli toxin MazF and its antitoxin MazE, with insertion of a protease cleavage site in the linker peptide connecting the MazE and MazF moieties. Expression of the viral protease confers cleavage of the MazEF fusion, releasing the MazF toxin from its antitoxin, resulting in growth inhibition. In the presence of a small molecule inhibiting the protease, cleavage is blocked and the MazF toxin remains inhibited, promoting growth. The system thus allows positive selection for inhibitors. The engineered yeast strain is tagged with a fluorescent marker protein, allowing precise monitoring of its growth in the presence or absence of inhibitor. We detect an established main protease inhibitor by a robust growth increase, discernible down to 1 mM. The system is suitable for robotized large-scale screens. It allows in vivo evaluation of drug candidates and is rapidly adaptable for new variants of the protease with deviant site specificities. IMPORTANCE The COVID-19 pandemic may continue for several years before vaccination campaigns can put an end to it globally. Thus, the need for discovery of new antiviral drug candidates will remain. We have engineered a system in yeast cells for the detection of small molecule inhibitors of one attractive drug target of SARS-CoV-2, its main protease, which is required for viral replication. The ability to detect inhibitors in live cells brings the advantage that only compounds capable of entering the cell and remain stable there will score in the system. Moreover, because of its design in yeast cells, the system is rapidly adaptable for tuning the detection level and eventual modification of the protease cleavage site in the case of future mutant variants of the SARSCoV-2 main protease or even for other proteases.
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| 6. |
- Alalam, Hanna, et al.
(författare)
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A High-Throughput Method for Screening for Genes Controlling Bacterial Conjugation of Antibiotic Resistance.
- 2020
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Ingår i: mSystems. - 2379-5077. ; 5:6
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Tidskriftsartikel (refereegranskat)abstract
- The rapid horizontal transmission of antibiotic resistance genes on conjugative plasmids between bacterial host cells is a major cause of the accelerating antibiotic resistance crisis. There are currently no experimental platforms for fast and cost-efficient screening of genetic effects on antibiotic resistance transmission by conjugation, which prevents understanding and targeting conjugation. We introduce a novel experimental framework to screen for conjugation-based horizontal transmission of antibiotic resistance between >60,000 pairs of cell populations in parallel. Plasmid-carrying donor strains are constructed in high-throughput. We then mix the resistance plasmid-carrying donors with recipients in a design where only transconjugants can reproduce, measure growth in dense intervals, and extract transmission times as the growth lag. As proof-of-principle, we exhaustively explore chromosomal genes controlling F-plasmid donation within Escherichia coli populations, by screening the Keio deletion collection in high replication. We recover all seven known chromosomal gene mutants affecting conjugation as donors and identify many novel mutants, all of which diminish antibiotic resistance transmission. We validate nine of the novel genes' effects in liquid mating assays and complement one of the novel genes' effect on conjugation (rseA). The new framework holds great potential for exhaustive disclosing of candidate targets for helper drugs that delay resistance development in patients and societies and improve the longevity of current and future antibiotics. Further, the platform can easily be adapted to explore interspecies conjugation, plasmid-borne factors, and experimental evolution and be used for rapid construction of strains.IMPORTANCE The rapid transmission of antibiotic resistance genes on conjugative plasmids between bacterial host cells is a major cause of the accelerating antibiotic resistance crisis. There are currently no experimental platforms for fast and cost-efficient screening of genetic effects on antibiotic resistance transmission by conjugation, which prevents understanding and targeting conjugation. We introduce a novel experimental framework to screen for conjugation-based horizontal transmission of antibiotic resistance between >60,000 pairs of cell populations in parallel. As proof-of-principle, we exhaustively explore chromosomal genes controlling F-plasmid donation within E. coli populations. We recover all previously known and many novel chromosomal gene mutants that affect conjugation efficiency. The new framework holds great potential for rapid screening of compounds that decrease transmission. Further, the platform can easily be adapted to explore interspecies conjugation, plasmid-borne factors, and experimental evolution and be used for rapid construction of strains.
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| 7. |
- Alalam, Hanna, et al.
(författare)
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Conjugation factors controlling F-plasmid antibiotic resistance transmission
- 2018
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Ingår i: BioRxiv. - : Cold Spring Harbor Laboratory.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The rapid horizontal transmission of many antibiotic resistance genes between bacterial host cells on conjugative plasmids is a major cause of the accelerating antibiotic resistance crisis. Preventing understanding and targeting conjugation, there currently are no experimental platforms for fast and cost-efficient screening of genetic effects on antibiotic resistance transmission by conjugation. We introduce a novel experimental framework to screen for conjugation based horizontal transmission of antibiotic resistance between >60,000 pairs of cell populations in parallel. Plasmid-carrying donor strains are constructed in high throughput. We then mix the resistance plasmid carrying donors with recipients in a design where only transconjugants can reproduce, measure growth in dense intervals and extract transmission times as the growth lag. As proof-of-principle, we exhaustively explored chromosomal genes controlling F plasmid donation within E. coli populations, by screening the Keio deletion collection at high replication. We recover all six known chromosomal gene mutants affecting conjugation and identify >50 novel factors, all of which diminish antibiotic resistance transmission. We verify 10 of the novel genes' effects in a liquid mating assay. The new framework holds great potential for exhaustive disclosing of candidate targets for helper drugs that delay resistance development in patients and societies and improves the longevity of current and future antibiotics.
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| 8. |
- Alalam, Hanna, et al.
(författare)
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Global SLAM-Seq for accurate mRNA decay determination and identification of NMD targets.
- 2022
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Ingår i: RNA. - : Cold Spring Harbor Laboratory. - 1469-9001 .- 1355-8382. ; 28:7
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Tidskriftsartikel (refereegranskat)abstract
- Gene expression analysis requires accurate measurements of global RNA degradation rates, earlier problematic with methods disruptive to cell physiology. Recently, metabolic RNA labeling emerged as an efficient and minimally invasive technique applied in mammalian cells. Here, we have adapted SH-Linked Alkylation for the Metabolic Sequencing of RNA (SLAM-Seq) for a global mRNA stability study in yeast using 4-thiouracil pulse-chase labeling. We assign high-confidence half-life estimates for 67.5 % of expressed ORFs, and measure a median half-life of 9.4 min. For mRNAs where half-life estimates exist in the literature, their ranking order was in good agreement with previous data, indicating that SLAM-Seq efficiently classifies stable and unstable transcripts. We then leveraged our yeast protocol to identify targets of the Nonsense-mediated decay (NMD) pathway by measuring the change in RNA half-lives; instead of steady-state RNA level changes. With SLAM-Seq, we assign 580 transcripts as putative NMD targets, based on their measured half-lives in wild-type and upf3Δ mutants. We find 225 novel targets, and observe a strong agreement with previous reports of NMD targets, 61.2 % of our candidates being identified in previous studies. This indicates that SLAM-Seq is a simpler and more economic method for global quantification of mRNA half-lives. Our adaptation for yeast yielded global quantitative measures of the NMD effect on transcript half-lives, high correlation with RNA half-lives measured previously with more technically challenging protocols, and identification of novel NMD regulated transcripts that escaped prior detection.
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| 9. |
- Alao, John Patrick, 1973, et al.
(författare)
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Caffeine as a tool for investigating the integration of Cdc25 phosphorylation, activity and ubiquitin-dependent degradation in Schizosaccharomyces pombe.
- 2020
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Ingår i: Cell Division. - : Springer Science and Business Media LLC. - 1747-1028. ; 15
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Forskningsöversikt (refereegranskat)abstract
- The evolutionarily conserved Cdc25 phosphatase is an essential protein that removes inhibitory phosphorylation moieties on the mitotic regulator Cdc2. Together with the Wee1 kinase, a negative regulator of Cdc2 activity, Cdc25 is thus a central regulator of cell cycle progression in Schizosaccharomyces pombe. The expression and activity of Cdc25 is dependent on the activity of the Target of Rapamycin Complex 1 (TORC1). TORC1 inhibition leads to the activation of Cdc25 and repression of Wee1, leading to advanced entry into mitosis. Withdrawal of nitrogen leads to rapid Cdc25 degradation via the ubiquitin- dependent degradation pathway by the Pub1 E3- ligase. Caffeine is believed to mediate the override of DNA damage checkpoint signalling, by inhibiting the activity of the ataxia telangiectasia mutated (ATM)/Rad3 homologues. This model remains controversial, as TORC1 appears to be the preferred target of caffeine in vivo. Recent studies suggest that caffeine induces DNA damage checkpoint override by inducing the nuclear accumulation of Cdc25 in S. pombe. Caffeine may thus modulate Cdc25 activity and stability via inhibition of TORC1. A clearer understanding of the mechanisms by which caffeine stabilises Cdc25, may provide novel insights into how TORC1 and DNA damage signalling is integrated.
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| 10. |
- Alao, John Patrick, 1973, et al.
(författare)
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Caffeine stabilises fission yeast Wee1 in a Rad24-dependent manner but attenuates Its expression in response to DNA damage.
- 2020
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Ingår i: Microorganisms. - : MDPI AG. - 2076-2607. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- The widely consumed neuroactive compound caffeine has generated much interest due to its ability to override the DNA damage and replication checkpoints. Previously Rad3 and its homologues was thought to be the target of caffeine's inhibitory activity. Later findings indicate that the Target of Rapamycin Complex 1 (TORC1) is the preferred target of caffeine. Effective Cdc2 inhibition requires both the activation of the Wee1 kinase and inhibition of the Cdc25 phosphatase. The TORC1, DNA damage, and environmental stress response pathways all converge on Cdc25 and Wee1. We previously demonstrated that caffeine overrides DNA damage checkpoints by modulating Cdc25 stability. The effect of caffeine on cell cycle progression resembles that of TORC1 inhibition. Furthermore, caffeine activates the Sty1 regulated environmental stress response. Caffeine may thus modulate multiple signalling pathways that regulate Cdc25 and Wee1 levels, localisation and activity. Here we show that the activity of caffeine stabilises both Cdc25 and Wee1. The stabilising effect of caffeine and genotoxic agents on Wee1 was dependent on the Rad24 chaperone. Interestingly, caffeine inhibited the accumulation of Wee1 in response to DNA damage. Caffeine may modulate cell cycle progression through increased Cdc25 activity and Wee1 repression following DNA damage via TORC1 inhibition, as TORC1 inhibition increased DNA damage sensitivity.
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| 11. |
- Alao, John Patrick, 1973, et al.
(författare)
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Caffeine stabilizes Cdc25 independently of Rad3 in Schizosaccharomyces pombe contributing to checkpoint override
- 2014
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Ingår i: Molecular Microbiology. - : Wiley. - 0950-382X .- 1365-2958. ; 92:4, s. 777-796
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Tidskriftsartikel (refereegranskat)abstract
- Cdc25 is required for Cdc2 dephosphorylation and is thus essential for cell cycle progression. Checkpoint activation requires dual inhibition of Cdc25 and Cdc2 in a Rad3-dependent manner. Caffeine is believed to override activation of the replication and DNA damage checkpoints by inhibiting Rad3-related proteins in both Schizosaccharomyces pombe and mammalian cells. In this study, we have investigated the impact of caffeine on Cdc25 stability, cell cycle progression and checkpoint override. Caffeine induced Cdc25 accumulation in S.pombe independently of Rad3. Caffeine delayed cell cycle progression under normal conditions but advanced mitosis in cells treated with replication inhibitors and DNA-damaging agents. In the absence of Cdc25, caffeine inhibited cell cycle progression even in the presence of hydroxyurea or phleomycin. Caffeine induces Cdc25 accumulation in S.pombe by suppressing its degradation independently of Rad3. The induction of Cdc25 accumulation was not associated with accelerated progression through mitosis, but rather with delayed progression through cytokinesis. Caffeine-induced Cdc25 accumulation appears to underlie its ability to override cell cycle checkpoints. The impact of Cdc25 accumulation on cell cycle progression is attenuated by Srk1 and Mad2. Together our findings suggest that caffeine overrides checkpoint enforcement by inducing the inappropriate nuclear localization of Cdc25.
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| 12. |
- Alao, John Patrick, 1973, et al.
(författare)
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Hyperosmosis enhances radiation and hydroxyurea resistance of S. pombe checkpoint mutants through the spindle checkpoint and delayed cytokinesis
- 2010
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Ingår i: Molecular Microbiology. - : Wiley. - 0950-382X. ; 77:1, s. 143-157
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Tidskriftsartikel (refereegranskat)abstract
- The DNA damage and stress response pathways interact to regulate cellular responses to genotoxins and environmental stresses. How these pathways interact in Schizosaccharomyces pombe is not well understood. We demonstrate that osmotic stress suppresses the DNA damage sensitivity of checkpoint mutants, and that this occurs through three distinct cell cycle delays. A delay in G2/M is dependent on Srk1. Progression through mitosis is halted by a Mad2-dependent spindle checkpoint. Finally, cytokinesis is impaired by modulating Cdc25 expression. These three delays, imposed by osmotic stress, together compensate for the loss of checkpoint signalling.
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| 13. |
- Alao, John Patrick, 1973, et al.
(författare)
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Inhibition of type I histone deacetylase increases resistance of checkpoint-deficient cells to genotoxic agents through mitotic delay
- 2009
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Ingår i: Molecular Cancer Therapeutics. - 1535-7163 .- 1538-8514. ; 8, s. 2606-2615
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Tidskriftsartikel (refereegranskat)abstract
- Histone deacetylase (HDAC) inhibitors potently inhibit tumor growth and are currently being evaluated for their efficacy as chemosensitizers and radiosensitizers. This efficacy is likely to be limited by the fact that HDACinhibitors also induce cell cycle arrest. Deletion of the class I HDACRpd3 has been shown to specifically suppress the sensitivity of Saccharomyces cerevisiae DNA damage checkpoint mutants to UV and hydroxyurea. We show that in the fission yeast Schizosaccharomyces pombe, inhibition of the homologous class I HDACspe cifically suppresses the DNA damage sensitivity of checkpoint mutants. Importantly, the prototype HDACinhibitor Trichostatin A also suppressed the sensitivity of DNA damage checkpoint but not of DNA repair mutants to UV and HU. TSA suppressed DNA damage activity independently of the mitogen-activated protein kinase–dependent and spindle checkpoint pathways. We show that TSA delays progression into mitosis and propose that this is the main mechanism for suppression of the DNA damage sensitivity of S. pombe checkpoint mutants, partially compensating for the loss of the G2 checkpoint pathway. Our studies also show that the ability of HDACinhibitors to suppress DNA damage sensitivity is not species specific. Class I HDACs are the major target of HDAC inhibitors and cancer cells are often defective in checkpoint activation. Effective use of these agents as chemosensitizers and radiosensitizers may require specific treatment schedules that circumvent their inhibition of cell cycle progression.
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| 14. |
- Alao, John Patrick, 1973, et al.
(författare)
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Rad3 and Sty1 function in S. pombe: an integrated response to DNA damage and environmental stress?
- 2008
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Ingår i: Molecular Microbiology. - : Wiley. - 0950-382X. ; 68, s. 246-254
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Forskningsöversikt (refereegranskat)abstract
- In Schizosaccharomyces pombe, the Ataxia Telangiectasia-mutated (Atm)/Atm and Rad 3 Related (Atr) homologue Rad3 is an essential regulator of the response to DNA damage and stalled replication forks. Rad3 activates the downstream kinases Chk1 and Cds1. These kinases in turn inhibit cell cycle progression by mediating Cdc2 phosphorylation. Studies in both yeast and mammalian cells suggest additional roles for Rad3 in regulating cellular responses to environmental stress. In S. pombe, cellular responses to various environmental stresses are regulated primarily through the stress-activated MAP kinase p38 homologue Sty1. An important function of Sty1 is to drive cells rapidly through mitosis by facilitating the accumulation of Cdc25. Interestingly, Sty1 is activated simultaneously with Rad3 following exposure to UV radiation or ionizing radiation (IR). Similarly, exposure to environmental stresses induces the expression of rad3+, cds1+ and other checkpoint regulator genes. It is currently unclear how the pathways regulated by Sty1 and Rad3 and their opposing effects on mitosis are integrated. Recent studies suggest that Sty1 and Rad3 function together to regulate the expression of several stress response genes following exposure to IR. In this review, we discuss current knowledge on the interaction of Rad3/Atm and Sty1/p38 in regulating cellular responses to environmental stress and DNA damage.
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| 15. |
- Alao, John Patrick, 1973, et al.
(författare)
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Selective inhibition of RET mediated cell proliferation in vitro by the kinase inhibitor SPP86
- 2014
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Ingår i: BMC Cancer. - : BioMed Central. - 1471-2407. ; 14:853
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe RET tyrosine kinase receptor has emerged as a target in thyroid and endocrine resistant breast cancer. We previously reported the synthesis of kinase inhibitors with potent activity against RET. Herein, we have further investigated the effect of the lead compound SPP86 on RET mediated signaling and proliferation. Based on these observations, we hypothesized that SPP86 may be useful for studying the cellular activity of RET.MethodsWe compared the effects of SPP86 on RET-induced signaling and proliferation in thyroid cancer cell lines expressing RET-PTC1 (TPC1), or the activating mutations BRAFV600E (8505C) and RASG13R (C643). The effect of SPP86 on RET- induced phosphatidylinositide 3-kinases (PI3K)/Akt and MAPK pathway signaling and cell proliferation in MCF7 breast cancer cells was also investigated.ResultsSPP86 inhibited MAPK signaling and proliferation in RET/PTC1 expressing TPC1 but not 8505C or C643 cells. In TPC1 cells, the inhibition of RET phosphorylation required co-exposure to SPP86 and the focal adhesion kinase (FAK) inhibitor PF573228. In MCF7 cells, SPP86 inhibited RET- induced phosphatidylinositide 3-kinases (PI3K)/Akt and MAPK signaling and estrogen receptorα (ERα) phosphorylation, and inhibited proliferation to a similar degree as tamoxifen. Interestingly, SPP86 and PF573228 inhibited RET/PTC1 and GDNF- RET induced activation of Akt and MAPK signaling to a similar degree.ConclusionSPP86 selectively inhibits RET downstream signaling in RET/PTC1 but not BRAFV600E or RASG13R expressing cells, indicating that downstream kinases were not affected. SPP86 also inhibited RET signaling in MCF7 breast cancer cells. Additionally, RET- FAK crosstalk may play a key role in facilitating PTC1/RET and GDNF- RET induced activation of Akt and MAPK signaling in TPC1 and MCF7 cells.
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| 16. |
- Alao, John Patrick, 1973, et al.
(författare)
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Suppression of sensitivity to drugs and antibiotics by high external cation concentrations in fission yeast
- 2015
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Ingår i: PLoS One. - : Public Library of Science (PLoS). - 1932-6203. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- Background Potassium ion homeostasis plays an important role in regulating membrane potential and therefore resistance to cations, antibiotics and chemotherapeutic agents in Schizosaccharomyces pombe and other yeasts. However, the precise relationship between drug resistance in S. pombe and external potassium concentrations (particularly in its natural habitats) remains unclear. S. pombe can tolerate a wide range of external potassium concentrations which in turn affect plasma membrane polarization. We thus hypothesized that high external potassium concentrations suppress the sensitivity of this yeast to various drugs. Methods We have investigated the effect of external KCl concentrations on the sensitivity of S. pombe cells to a wide range of antibiotics, antimicrobial agents and chemotherapeutic drugs. We employed survival assays, immunoblotting and microscopy for these studies. Results We demonstrate that KCl, and to a lesser extent NaCl and RbCl can suppress the sensitivity of S. pombe to a wide range of antibiotics. Ammonium chloride and potassium hydrogen sulphate also suppressed drug sensitivity. This effect appears to depend in part on changes to membrane polarization and membrane transport proteins. Interestingly, we have found little relationship between the suppressive effect of KCl on sensitivity and the structure, polarity or solubility of the various compounds investigated. Conclusions High concentrations of external potassium and other cations suppress sensitivity to a wide range of drugs in S. pombe. Potassium-rich environments may thus provide S. pombe a competitive advantage in nature. Modulating potassium ion homeostasis may sensitize pathogenic fungi to antifungal agents.
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| 17. |
- Alao, John Patrick, 1973, et al.
(författare)
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The ATM and ATR inhibitors CGK733 and caffeine suppress cyclin D1 levels and inhibit cell proliferation
- 2009
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Ingår i: Radiation Oncology. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- The ataxia telangiectasia mutated (ATM) and the ATM- related (ATR) kinases play a central role in facilitating the resistance of cancer cells to genotoxic treatment regimens. The components of the ATM and ATR regulated signaling pathways thus provide attractive pharmacological targets, since their inhibition enhances cellular sensitivity to chemo- and radiotherapy. Caffeine as well as more specific inhibitors of ATM (KU55933) or ATM and ATR (CGK733) have recently been shown to induce cell death in drug-induced senescent tumor cells. Addition of these agents to cancer cells previously rendered senescent by exposure to genotoxins suppressed the ATM mediated p21 expression required for the survival of these cells. The precise molecular pharmacology of these agents however, is not well characterized. Herein, we report that caffeine, CGK733, and to a lesser extent KU55933, inhibit the proliferation of otherwise untreated human cancer and non-transformed mouse fibroblast cell lines. Exposure of human cancer cell lines to caffeine and CGK733 was associated with a rapid decline in cyclin D1 protein levels and a reduction in the levels of both phosphorylated and total retinoblastoma protein (RB). Our studies suggest that observations based on the effects of these compounds on cell proliferation and survival must be interpreted with caution. The differential effects of caffeine/ CGK733 and KU55933 on cyclin D1 protein levels suggest that these agents will exhibit dissimilar molecular pharmacological profiles.
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| 18. |
- Asp, Eva, 1970, et al.
(författare)
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Fission yeast mitogen-activated protein kinase Sty1 interacts with translation factors
- 2008
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Ingår i: Eukaryot. Cell. ; 7, s. 328-338
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Tidskriftsartikel (refereegranskat)abstract
- Signaling by stress-activated mitogen-activated protein kinase (MAPK) pathways influences translation efficiency in mammalian cells and budding yeast. We have investigated the stress-activated MAPK from fission yeast, Sty1, and its downstream protein kinase, Mkp1/Srk1, for physically associated proteins using tandem affinity purification tagging. We find Sty1, but not Mkp1, to bind to the translation elongation factor eukaryotic elongation factor 2 (eEF2) and the translation initiation factor eukaryotic initiation factor 3a (eIF3a). The Sty1-eIF3a interaction is weakened under oxidative or hyperosmotic stress, whereas the Sty1-eEF2 interaction is stable. Nitrogen deprivation causes a transient strengthening of both the Sty1-eEF2 and the Sty1-Mkp1 interactions, overlapping with the time of maximal Sty1 activation. Analysis of polysome profiles from cells under oxidative stress, or after hyperosmotic shock or nitrogen deprivation, shows that translation in sty1 mutant cells recovers considerably less efficiently than that in the wild type. Cells lacking the Sty1-regulated transcription factor Atf1 are deficient in maintaining and recovering translational activity after hyperosmotic shock but not during oxidative stress or nitrogen starvation. In cells lacking Sty1, eIF3a levels are decreased, and phosphorylation of eIF3a is reduced. Taken together, our data point to a central role in translational adaptation for the stress-activated MAPK pathway in fission yeast similar to that in other investigated eukaryotes, with the exception that fission yeast MAPK-activated protein kinases seem not to be directly involved in this process.
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| 19. |
- Asp, Eva, 1970, et al.
(författare)
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Mkp1 and Mkp2, two MAPKAP-kinase homologues in Schizosaccharomyces pombe, interact with the MAP kinase Sty1
- 2003
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Ingår i: Molecular Genetics and Genomics. - 1617-4615 .- 1617-4623. ; 268, s. 585-597
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Tidskriftsartikel (refereegranskat)abstract
- Mkp1 ( MAPKAP kinase Schizosaccharomyces pombe 1) and Mkp2 are two members from fission yeast of the sub-class of putative MAPK-activated protein kinases in yeasts, the other known members being Rck1 and Rck2 from Saccharomyces cerevisiae. The Mkp1 protein is readily co-immunoprecipitated with Sty1 from S. pombe extracts; Mkp2 shows a weaker interaction with Sty1. In mkp1 mutants, conjugation and meiosis proceed more readily and rapidly than in wild-type cells, in analogy to what was previously found for S. cerevisiae rck1 mutants. Conversely, overexpression of mkp1(+) delays meiosis. Mkp1 is phosphorylated in vivo in a sty1(+)-dependent manner; this modification is removed when cells are starved for nitrogen, a condition that is conducive to entry into stationary phase and meiosis. Overexpression of mkp1(+), like a sty1 mutation, also causes vegetative cells to elongate. The level of Mkp1 phosphorylation drops as cells enter mitosis. We have localised Mkp1 to the cytoplasm, excluded from the nucleus, in vegetative cells. The Mkp1 protein accumulates in zygotic asci and is concentrated within spores. The mkp2(+) gene has no noticeable impact on meiosis. Mkp2 is excluded from the nucleus in vegetative cells, and is concentrated at the septa of dividing cells. Mkp2 does not accumulate in meiotic cells.
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| 20. |
- Axelson-Fisk, Marina, et al.
(författare)
-
Comparative genomics and gene finding in fungi
- 2006
-
Ingår i: Topics in Current Genetics. ; 15, s. 1-28
-
Forskningsöversikt (refereegranskat)abstract
- In the spring of 2005, we had access to 18 fully sequenced fungal genomes, and more are coming rapidly. New approaches and methods are being developed to harvest this information source to derive functional predictions and understanding of genome anatomy. Comparative genomics also tells us stories about the evolution of yeasts and filamentous fungi, and the genome rearrangements that marked their history. For example, several genes encoding proteins required for heterochromatin formation and RNA interference have been lost uniformly throughout the Hemiascomycetes, although some genes remain in a few species in a scattered pattern. Being the first eukaryote to have its genome fully sequenced, Saccharomyces cerevisiae was the forerunner for in silico methods of genome annotation in general, and gene finding in particular. Lessons learned from the comparatively simple genome of this budding yeast have paved the way for efficient genome analysis in other fungi as well as eukaryotes in general. Several fungal species are of important applied interest for mankind, and so it is essential to utilise comparative genomics to derive functional information about them. The set of fungal genomes: simple, related in evolution, and with a high density of functional information, can serve as a highly efficient test bed for the further development of comparative genomics.
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| 21. |
- Axelson-Fisk, Marina, 1972, et al.
(författare)
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Gene finding in fungal genomes
- 2005
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Ingår i: Topics in Current Genetics: Comparative genomics using fungi as models. - 9783540314806 ; , s. 1-28
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 22. |
- Barreto, L., et al.
(författare)
-
A peroxisomal glutathione transferase of Saccharomyces cerevisiae is functionally related to sulfur amino acid metabolism
- 2006
-
Ingår i: Eukaryot Cell. ; 5:10, s. 1748-59
-
Tidskriftsartikel (refereegranskat)abstract
- Saccharomyces cerevisiae cells contain three omega-class glutathione transferases with glutaredoxin activity (Gto1, Gto2, and Gto3), in addition to two glutathione transferases (Gtt1 and Gtt2) not classifiable into standard classes. Gto1 is located at the peroxisomes, where it is targeted through a PTS1-type sequence, whereas Gto2 and Gto3 are in the cytosol. Among the GTO genes, GTO2 shows the strongest induction of expression by agents such as diamide, 1-chloro-2,4-dinitrobenzene, tert-butyl hydroperoxide or cadmium, in a manner that is dependent on transcriptional factors Yap1 and/or Msn2/4. Diamide and 1-chloro-2,4-dinitrobenzene (causing depletion of reduced glutathione) also induce expression of GTO1 over basal levels. Phenotypic analyses with single and multiple mutants in the S. cerevisiae glutathione transferase genes show that, in the absence of Gto1 and the two Gtt proteins, cells display increased sensitivity to cadmium. A gto1-null mutant also shows growth defects on oleic acid-based medium, which is indicative of abnormal peroxisomal functions, and altered expression of genes related to sulfur amino acid metabolism. As a consequence, growth of the gto1 mutant is delayed in growth medium without lysine, serine, or threonine, and the mutant cells have low levels of reduced glutathione. The role of Gto1 at the S. cerevisiae peroxisomes could be related to the redox regulation of the Str3 cystathionine beta-lyase protein. This protein is also located at the peroxisomes in S. cerevisiae, where it is involved in transulfuration of cysteine into homocysteine, and requires a conserved cysteine residue for its biological activity.
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| 23. |
- Bilsland, Elizabeth, 1973, et al.
(författare)
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Rck1 and Rck2 MAPKAP kinases and the HOG pathway are required for oxidative stress resistance
- 2004
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Ingår i: Molecular Microbiology. - : Wiley. - 0950-382X .- 1365-2958. ; 53:6, s. 1743-56
-
Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a role in oxidative and metal stress resistance for the MAPK-activated protein kinases Rck1 and Rck2 in Saccharomyces cerevisiae. We show that Hog1 is robustly phosphorylated in a Pbs2-dependent way during oxidative stress, and that Rck2 also is phosphorylated under these circumstances. Hog1 concentrates in the nucleus in oxidative stress. Hog1 localization is partially dependent on Rck2, as rck2 cells have more nuclear Hog1 than wild-type cells. We find several proteins with a role in oxidative stress resistance using Rck1 or Rck2 as baits in a two-hybrid screen. We identify the transcription factor Yap2 as a putative target for Rck1, and the Zn2+ transporter Zrc1 as a target for Rck2. Yap2 is normally cytoplasmic, but rapidly migrates to the nucleus upon exposure to oxidative stress agents. In a fraction of untreated pbs2 cells, Yap2 is nuclear. Zrc1 co-immunoprecipitates with Rck2, and ZRC1 is genetically downstream of RCK2. These data connect activation of the Hog1 MAPK cascade with effectors having a role in oxidative stress resistance.
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| 24. |
- Bilsland, Elizabeth, 1973, et al.
(författare)
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The Bre5/Ubp3 ubiquitin protease complex from budding yeast contributes to the cellular response to DNA damage
- 2007
-
Ingår i: DNA Repair (Amst). - : Elsevier BV. - 1568-7864. ; 6:10, s. 1471-84
-
Tidskriftsartikel (refereegranskat)abstract
- The ubiquitination status of proteins can control numerous aspects of protein function through targeted destruction or by altering protein-protein interactions, subcellular localization, or enzymatic activity. In addition to enzymes that mediate the conjugation of ubiquitin moieties to target proteins, there are enzymes that catalyze the removal of ubiquitin, termed ubiquitin proteases. One such ubiquitin protease, Ubp3, exists in a complex with a partner protein: Bre5. This complex has been implicated in a variety of cellular activities, and was recently identified in large-scale screens for genetic interactions with known components of the DNA damage response pathway. We found that this complex plays a role in the cellular response to the DNA damaging agent phleomycin and strains lacking the complex have a defect in non-homologous end joining. Although this complex is also important for telomeric silencing, maintenance of the cell wall, and global transcriptional regulation, we present evidence suggesting that the role of this complex in DNA damage responses is distinct from these other roles. First, we found that Ubp3/Bre5 functions antagonistically with Bul1 in DNA damage responses, but not in its other cellular functions. Additionally, we have generated mutants of Bre5 that are specifically defective in DNA damage responses.
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| 25. |
- Bourgard, Catarina, 1985, et al.
(författare)
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Development of Dicationic Bisguanidine-Arylfuran Derivatives as Potent Agents against Gram-Negative Bacteria.
- 2022
-
Ingår i: Antibiotics. - : MDPI AG. - 2079-6382. ; 11:8
-
Tidskriftsartikel (refereegranskat)abstract
- Antibiotic resistance among bacteria is a growing global challenge. A major reason for this is the limited progress in developing new classes of antibiotics active against Gram-negative bacteria. Here, we investigate the antibacterial activity of a dicationic bisguanidine-arylfuran, originally developed as an antitrypanosomal agent, and new derivatives thereof. The compounds showed good activity (EC50 2-20 µM) against antibiotic-resistant isolates of the Gram-negative members of the ESKAPE group (Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.) and Escherichia coli with different antibiotic susceptibility patterns, including ESBL isolates. Cytotoxicity was moderate, and several of the new derivatives were less cytotoxic than the lead molecule, offering better selectivity indices (40-80 for several ESKAPE isolates). The molecular mechanism for the antibacterial activity of these molecules is unknown, but sensitivity profiling against human ESKAPE isolates and E. coli collections with known susceptibility patterns against established antibiotics indicates that it is distinct from lactam and quinolone antibiotics.
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| 26. |
- Bourgard, Catarina, 1985, et al.
(författare)
-
Plasmodium vivax Biology: Insights Provided by Genomics, Transcriptomics and Proteomics.
- 2018
-
Ingår i: Frontiers in Cellular and Infection Microbiology. - : Frontiers Media SA. - 2235-2988. ; 8
-
Forskningsöversikt (refereegranskat)abstract
- During the last decade, the vast omics field has revolutionized biological research, especially the genomics, transcriptomics and proteomics branches, as technological tools become available to the field researcher and allow difficult question-driven studies to be addressed. Parasitology has greatly benefited from next generation sequencing (NGS) projects, which have resulted in a broadened comprehension of basic parasite molecular biology, ecology and epidemiology. Malariology is one example where application of this technology has greatly contributed to a better understanding ofPlasmodiumspp. biology and host-parasite interactions. Among the several parasite species that cause human malaria, the neglected Plasmodium vivax presents great research challenges, asin vitroculturing is not yet feasible and functional assays are heavily limited. Therefore, there are gaps in our P. vivax biology knowledge that affect decisions for control policies aiming to eradicate vivax malaria in the near future. In this review, we provide a snapshot of key discoveries already achieved in P. vivax sequencing projects, focusing on developments, hurdles, and limitations currently faced by the research community, as well as perspectives on future vivax malaria research.
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| 27. |
- Corbacho, Isaac, et al.
(författare)
-
Genome-wide expression profile of the mnn2Δ mutant of Saccharomyces cerevisiae
- 2006
-
Ingår i: Antonie van Leeuwenhoek. - : Springer Science and Business Media LLC. - 0003-6072 .- 1572-9699. ; 89:3-4, s. 485-494
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract The MNN2 gene of S. cerevisiae encodes an α (1,2) mannosyl transferase required for branching the outer chain of N-linked oligosaccharides (Rayner J.C. and Munro S. 1998. J. Biol. Chem. 273: 2683626843) and it also seems to have some effect on the transfer of mannosyl phosphate groups to the inner core (Olivero I. et al. 2000. FEBS Lett. 475: 111116). In order to reveal possible interactions of MNN2 expression with other cellular pathways, we analyzed the transcriptome of the deletion mutant S. cerevisiae mnn2Δ using cDNA microarrays. We found 151 genes that showed an altered expression level of ≥2-fold, 58 of them up-regulated and 93 down-regulated. Quite a high proportion of these genes (29%) encode unclassified proteins. In contrast to other defects affecting the integrity of the cell wall, deletion of MNN2 does not stimulate the expression of any of the genes included in the previously defined cell wall compensatory cluster (Lagorce et al. 2003. J. Biol. Chem. 278: 2034520357). We also found that 15% of the selected genes are related to central metabolic pathways. In addition, the mnn2Δ strain seems to have a certain level of stimulation of DNA processing reactions while some genes involved in intracellular transport pathways are under-regulated
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| 28. |
- Cvijovic, Marija, 1977, et al.
(författare)
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Identification of putative regulatory upstream ORFs in the yeast genome using heuristics and evolutionary conservation
- 2007
-
Ingår i: BMC Bioinformatics. - : Springer Science and Business Media LLC. - 1471-2105. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The translational efficiency of an mRNA can be modulated by upstream open reading frames (uORFs) present in certain genes. A uORF can attenuate translation of the main ORF by interfering with translational reinitiation at the main start codon. uORFs also occur by chance in the genome, in which case they do not have a regulatory role. Since the sequence determinants for functional uORFs are not understood, it is difficult to discriminate functional from spurious uORFs by sequence analysis. RESULTS: We have used comparative genomics to identify novel uORFs in yeast with a high likelihood of having a translational regulatory role. We examined uORFs, previously shown to play a role in regulation of translation in Saccharomyces cerevisiae, for evolutionary conservation within seven Saccharomyces species. Inspection of the set of conserved uORFs yielded the following three characteristics useful for discrimination of functional from spurious uORFs: a length between 4 and 6 codons, a distance from the start of the main ORF between 50 and 150 nucleotides, and finally a lack of overlap with, and clear separation from, neighbouring uORFs. These derived rules are inherently associated with uORFs with properties similar to the GCN4 locus, and may not detect most uORFs of other types. uORFs with high scores based on these rules showed a much higher evolutionary conservation than randomly selected uORFs. In a genome-wide scan in S. cerevisiae, we found 34 conserved uORFs from 32 genes that we predict to be functional; subsequent analysis showed the majority of these to be located within transcripts. A total of 252 genes were found containing conserved uORFs with properties indicative of a functional role; all but 7 are novel. Functional content analysis of this set identified an overrepresentation of genes involved in transcriptional control and development. CONCLUSION: Evolutionary conservation of uORFs in yeasts can be traced up to 100 million years of separation. The conserved uORFs have certain characteristics with respect to length, distance from each other and from the main start codon, and folding energy of the sequence. These newly found characteristics can be used to facilitate detection of other conserved uORFs.
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| 29. |
- Dahlén, Maria, 1965, et al.
(författare)
-
Replication proteins influence the maintenance of telomere length and telomerase protein stability
- 2003
-
Ingår i: Molecular and Cellular Biology. - 0270-7306 .- 1098-5549. ; 23, s. 3031-3042
-
Tidskriftsartikel (refereegranskat)abstract
- We investigated the effects of fission yeast replication genes on telomere length maintenance and identified 20 mutant alleles that confer lengthening or shortening of telomeres. The telomere elongation was telomerase dependent in the replication mutants analyzed. Furthermore, the telomerase catalytic subunit, Trt1, and the principal initiation and lagging-strand synthesis DNA polymerase, Polalpha, were reciprocally coimmunoprecipitated, indicating these proteins physically coexist as a complex in vivo. In a polalpha mutant that exhibited abnormal telomere lengthening and slightly reduced telomere position effect, the cellular level of the Trt1 protein was significantly lower and the coimmunoprecipitation of Trt1 and Polalpha was severely compromised compared to those in the wild-type polalpha cells. Interestingly, ectopic expression of wild-type polalpha in this polalpha mutant restored the cellular Trt1 protein to the wild-type level and shortened the telomeres to near-wild-type length. These results suggest that there is a close physical relationship between the replication and telomerase complexes. Thus, mutation of a component of the replication complex can affect the telomeric complex in maintaining both telomere length equilibrium and telomerase protein stability
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| 30. |
- Dinér, Peter, 1976, et al.
(författare)
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Preparation of 3-Substituted-1-Isopropyl-1H-pyrazolo 3,4-d pyrimidin-4-amines as RET Kinase Inhibitors
- 2012
-
Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 55:10, s. 4872-4876
-
Tidskriftsartikel (refereegranskat)abstract
- A series of 3-substituted-1-isopropyl-1H-pyrazolo[3,4-d]pyrimidin-4-amines have been designed, synthesized, and evaluated as RET protein kinase inhibitors. On the basis of docking results, a small library of pyrazolopyrimidine compounds with an extended hydrophobic side arm was synthesized. The most promising of the compounds (7a) displayed efficient inhibition in vitro and good selectivity when tested on a panel of kinases. Furthermore, 7a inhibited GDNF-induced RET phosphorylation of ERK1/2 in MCF-7 breast cancer cells at concentrations as low as 100 nM.
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| 31. |
- Dyrager, Christine, 1975, et al.
(författare)
-
Design, synthesis, and biological evaluation of chromone-based p38 MAP kinase inhibitors
- 2011
-
Ingår i: Journal of Medicinal Chemistry. ; 54, s. 7427-7431
-
Tidskriftsartikel (refereegranskat)abstract
- 3-(4-Fluorophenyl)-2-(4-pyridyl)chromone derivatives were synthesized and evaluated as p38 MAP kinase inhibitors. Introduction of an amino group in the 2-position of the pyridyl moiety gave p38α inhibitors with IC(50) in the low nanomolar range (e.g., IC(50) = 17 nm). The inhibitors showed excellent selectivity profiles when tested on a panel of 62 kinases, as well as efficient inhibition of p38 signaling in human breast cancer cells.
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| 32. |
- Endale, Milkyas, 1980, et al.
(författare)
-
Anthraquinones of the roots of Pentas micrantha
- 2013
-
Ingår i: Molecules. - : MDPI AG. - 1420-3049 .- 1431-5157. ; 18:1, s. 311-321
-
Tidskriftsartikel (refereegranskat)abstract
- Pentas micrantha is used in the East African indigenous medicine to treat malaria. In the first investigation of this plant, the crude methanol root extract showed moderate antiplasmodial activity against the W2- (3.37 μg/mL) and D6-strains (4.00 μg/mL) of Plasmodium falciparum and low cytotoxicity (>450 μg/mL, MCF-7 cell line). Chromatographic separation of the extract yielded nine anthraquinones, of which 5,6-dihydroxylucidin-11-O-methyl ether is new. Isolation of a munjistin derivative from the genus Pentas is reported here for the first time. The isolated constituents were identified by NMR and mass spectrometric techniques and showed low antiplasmodial activities.
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| 33. |
- Endale, Milkyas, et al.
(författare)
-
Antiplasmodial Quinones from Pentas longiflora and Pentas lanceolata
- 2012
-
Ingår i: Planta Medica. - : Georg Thieme Verlag KG. - 0032-0943 .- 1439-0221. ; 78:1, s. 31-35
-
Tidskriftsartikel (refereegranskat)abstract
- The dichloromethane/methanol (1 : 1) extracts of the roots of Pentas longiflora and Pentas lanceolata showed low micromolar (IC50 = 0.9-3 µg/mL) in vitro antiplasmodial activity against chloroquine-resistant (W2) and chloroquine-sensitive (D6) strains of Plasmodium falciparum. Chromatographic separation of the extract of Pentas longiflora led to the isolation of the pyranonaphthoquinones pentalongin (1) and psychorubrin (2) with IC50 values below 1 µg/mL and the naphthalene derivative mollugin (3), which showed marginal activity. Similar treatment of Pentas lanceolata led to the isolation of eight anthraquinones (4-11, IC50 = 5-31 µg/mL) of which one is new (5,6-dihydroxydamnacanthol, 11), while three - nordamnacanthal (7), lucidin-ω-methyl ether (9), and damnacanthol (10) - are reported here for the first time from the genus Pentas. The compounds were identified by NMR and mass spectroscopic techniques.
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| 34. |
- Endale, Milkyas, 1980, et al.
(författare)
-
Busseihydroquinones A-D from the Roots of Pentas bussei
- 2012
-
Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 1520-6025 .- 0163-3864. ; 75, s. 1299-1304
-
Tidskriftsartikel (refereegranskat)abstract
- Four new naphthohydroquinones, named busseihydroquinones A–D (1–4), along with a known homoprenylated dihydronaphthoquinone (5), were isolated from the CH2Cl2/MeOH (1:1) extract of the roots of Pentas bussei. Although the genus Pentas is frequently used by traditional healers for the treatment of malaria, only marginal activities against the chloroquine-sensitive (D6) and the chloroquine-resistant (W2) strains of Plasmodium falciparum were observed for the crude root extract and the isolated constituents of this plant.
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| 35. |
- Ferreira, Letícia T, et al.
(författare)
-
Chemical Genomic Profiling Unveils the in Vitro and in Vivo Antiplasmodial Mechanism of Açaí (Euterpe oleracea Mart.) Polyphenols.
- 2019
-
Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 4:13, s. 15628-15635
-
Tidskriftsartikel (refereegranskat)abstract
- Malaria remains a major detrimental parasitic disease in the developing world, with more than 200 million cases annually. Widespread drug-resistant parasite strains push for the development of novel antimalarial drugs. Plant-derived natural products are key sources of antimalarial molecules. Euterpe oleracea Martius ("açaí") originates from Brazil and has anti-inflammatory and antineoplasic properties. Here, we evaluated the antimalarial efficacy of three phenolic fractions of açaí; total phenolics (1), nonanthocyanin phenolics (2), and total anthocyanins (3). In vitro, fraction 2 moderately inhibited parasite growth in chloroquine-sensitive (HB3) and multiresistant (Dd2) Plasmodium falciparum strains, while none of the fractions was toxic to noncancer cells. Despite the limited activity in vitro, the oral treatment with 20 mg/kg of fraction 1 reduced parasitemia by 89.4% in Plasmodium chabaudi-infected mice and prolonged survival. Contrasting in vitro and in vivo activities of 1 suggest key antiplasmodial roles for polyphenol metabolites rather than the fraction itself. Finally, we performed haploinsufficiency chemical genomic profiling (HIP) utilizing heterozygous Saccharomyces cerevisiae deletion mutants to identify molecular mechanisms of açaí fractions. HIP results indicate proteostasis as the main cellular pathway affected by fraction 2. These results open avenues to develop açaí polyphenols as potential new antimalarial candidates.
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| 36. |
- Ferreira, Letícia Tiburcio, et al.
(författare)
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Computational Chemogenomics Drug Repositioning Strategy Enables the Discovery of Epirubicin as a New Repurposed Hit for Plasmodium falciparum and P. vivax.
- 2020
-
Ingår i: Antimicrobial Agents and Chemotherapy. - 1098-6596. ; 64:9
-
Tidskriftsartikel (refereegranskat)abstract
- Widespread resistance against antimalarial drugs thwarts current efforts for controlling the disease and urges the discovery of new effective treatments. Drug repositioning is increasingly becoming an attractive strategy since it can reduce costs, risks, and time-to-market. Herein, we have used this strategy to identify novel antimalarial hits. We used a comparative in silico chemogenomics approach to select Plasmodium falciparum and Plasmodium vivax proteins as potential drug targets and analyzed them using a computer-assisted drug repositioning pipeline to identify approved drugs with potential antimalarial activity. Among the seven drugs identified as promising antimalarial candidates, the anthracycline epirubicin was selected for further experimental validation. Epirubicin was shown to be potent in vitro against sensitive and multidrug-resistant P. falciparum strains and P. vivax field isolates in the nanomolar range, as well as being effective against an in vivo murine model of Plasmodium yoelii Transmission-blocking activity was observed for epirubicin in vitro and in vivo Finally, using yeast-based haploinsufficiency chemical genomic profiling, we aimed to get insights into the mechanism of action of epirubicin. Beyond the target predicted in silico (a DNA gyrase in the apicoplast), functional assays suggested a GlcNac-1-P-transferase (GPT) enzyme as a potential target. Docking calculations predicted the binding mode of epirubicin with DNA gyrase and GPT proteins. Epirubicin is originally an antitumoral agent and presents associated toxicity. However, its antiplasmodial activity against not only P. falciparum but also P. vivax in different stages of the parasite life cycle supports the use of this drug as a scaffold for hit-to-lead optimization in malaria drug discovery.
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| 37. |
- Garre, Elena, 1978, et al.
(författare)
-
The Lsm1-7/Pat1 complex binds to stress-activated mRNAs and modulates the response to hyperosmotic shock.
- 2018
-
Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 14:7
-
Tidskriftsartikel (refereegranskat)abstract
- RNA-binding proteins (RBPs) establish the cellular fate of a transcript, but an understanding of these processes has been limited by a lack of identified specific interactions between RNA and protein molecules. Using MS2 RNA tagging, we have purified proteins associated with individual mRNA species induced by osmotic stress, STL1 and GPD1. We found members of the Lsm1-7/Pat1 RBP complex to preferentially bind these mRNAs, relative to the non-stress induced mRNAs, HYP2 and ASH1. To assess the functional importance, we mutated components of the Lsm1-7/Pat1 RBP complex and analyzed the impact on expression of osmostress gene products. We observed a defect in global translation inhibition under osmotic stress in pat1 and lsm1 mutants, which correlated with an abnormally high association of both non-stress and stress-induced mRNAs to translationally active polysomes. Additionally, for stress-induced proteins normally triggered only by moderate or high osmostress, in the mutants the protein levels rose high already at weak hyperosmosis. Analysis of ribosome passage on mRNAs through co-translational decay from the 5' end (5P-Seq) showed increased ribosome accumulation in lsm1 and pat1 mutants upstream of the start codon. This effect was particularly strong for mRNAs induced under osmostress. Thus, our results indicate that, in addition to its role in degradation, the Lsm1-7/Pat1 complex acts as a selective translational repressor, having stronger effect over the translation initiation of heavily expressed mRNAs. Binding of the Lsm1-7/Pat1p complex to osmostress-induced mRNAs mitigates their translation, suppressing it in conditions of weak or no stress, and avoiding a hyperresponse when triggered.
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| 38. |
- Garre, Elena, 1978, et al.
(författare)
-
Yeast mRNA cap-binding protein Cbc1/Sto1 is necessary for the rapid reprogramming of translation after hyperosmotic shock
- 2012
-
Ingår i: Molecular Biology of the Cell. - 1059-1524. ; 23:1, s. 137-150
-
Tidskriftsartikel (refereegranskat)abstract
- In response to osmotic stress, global translation is inhibited, but the mRNAs encoding stress-protective proteins are selectively translated to allow cell survival. To date, the mechanisms and factors involved in the specific translation of osmostress-responsive genes in Saccharomyces cerevisiae are unknown. We find that the mRNA cap-binding protein Cbc1 is important for yeast survival under osmotic stress. Our results provide new evidence supporting a role of Cbc1 in translation initiation. Cbc1 associates with polysomes, while the deletion of the CBC1 gene causes hypersensitivity to the translation inhibitor cycloheximide and yields synthetic “sickness” in cells with limiting amounts of translation initiator factor eIF4E. In cbc1Δ mutants, translation drops sharply under osmotic stress, the subsequent reinitiation of translation is retarded, and “processing bodies” containing untranslating mRNAs remain for long periods. Furthermore, osmostress-responsive mRNAs are transcriptionally induced after osmotic stress in cbc1Δ cells, but their rapid association with polysomes is delayed. However, in cells containing a thermosensitive eIF4E allele, their inability to grow at 37ºC is suppressed by hyperosmosis, and Cbc1 relocalizes from nucleus to cytoplasm. These data support a model in which eIF4E-translation could be stress-sensitive, while Cbc1-mediated translation is necessary for the rapid translation of osmostress-protective proteins under osmotic stress.
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| 39. |
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| 40. |
|
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| 41. |
- Gumula, Ivan, et al.
(författare)
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Flemingins G–O, Cytotoxic and Antioxidant Constituents of the Leaves of Flemingia grahamiana
- 2014
-
Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 77:9, s. 2060-2067
-
Tidskriftsartikel (refereegranskat)abstract
- The known flemingins A–C (1–3) and nine new chalcones, named flemingins G–O (4–12), along with deoxyhomoflemingin (13) and emodin (14) were isolated from a leaf extract of Flemingia grahamiana. The isolated chalcones were found to have a geranyl substituent modified into a chromene ring possessing a residual chain, as shown by spectroscopic methods. The leaf extract showed an IC50 value of 5.9 μg/mL in a DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay. The chalcones flemingins A, B, C, G, and H were active in the DPPH radical scavenging assay (ED50 4.4–8.9 μM), while flemingins A and C showed cytotoxicity against MCF-7 human breast cancer cells (IC50 8.9 and 7.6 μM, respectively).
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| 42. |
- Hernández-Elvira, Mariana, 1989, et al.
(författare)
-
Post-transcriptional regulation during stress.
- 2022
-
Ingår i: FEMS Yeast Research. - : Oxford University Press (OUP). - 1567-1364. ; 22:1
-
Forskningsöversikt (refereegranskat)abstract
- To remain competitive, cells exposed to stress of varying duration, rapidity of onset, and intensity, have to balance their expenditure on growth and proliferation versus stress protection. To a large degree dependent on the time scale of stress exposure, the different levels of gene expression control: transcriptional, post-transcriptional and post-translational, will be engaged in stress responses. The post-transcriptional level is appropriate for minute-scale responses to transient stress, and for recovery upon return to normal conditions. The turnover rate, translational activity, covalent modifications, and subcellular localisation of RNA species are regulated under stress by multiple cellular pathways. The interplay between these pathways is required to achieve the appropriate signalling intensity and prevent undue triggering of stress-activated pathways at low stress levels, avoid overshoot, and down-regulate the response in a timely fashion. As much of our understanding of post-transcriptional regulation has been gained in yeast, this review is written with a yeast bias, but attempts to generalise to other eukaryotes. It summarises aspects of how post-transcriptional events in eukaryotes mitigate short-term environmental stresses, and how different pathways interact to optimise the stress response under shifting external conditions.
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| 43. |
- Hu, Xiao-Lei, et al.
(författare)
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Rehabilitering efter stroke - Socialstyrelsens strokeriktlinjer medför nya utmaningar
- 2018
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Ingår i: Läkartidningen. - 0023-7205 .- 1652-7518. ; 115:51-52
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Tidskriftsartikel (refereegranskat)abstract
- Stroke rehabilitation has often been based on tradition instead of evidence-based methods in the clinical practice. The recently updated Swedish national stroke guidelines have emphasized the amount of evidence-based stroke rehabilitation that is expected to be implemented in clinical practice. The most important recommendations in regarding stroke rehabilitation are the early support discharge, a structured follow-up at the subacute stage for identifying unmet rehabilitation needs and high intensity task-specific training from early to chronic phases. Meanwhile, we have to use the resource in a most cost-effective ways, such as a newly developed Rehab-Compass, group education for patients and caregivers ("stroke school") and sufficient number of employees of different occupational groups including rehab-assistants, to provide stroke survivors more evidence-based rehabilitation. These inputs will not only improve quality of stroke care but also save the medical and community resource in the near future.
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| 44. |
- Hult, Malin, 1974, et al.
(författare)
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SAPK and control of translation
- 2008
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Ingår i: Topics in Current Genetics. ; 20, s. 299-310
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Forskningsöversikt (refereegranskat)abstract
- Posttranscriptional control of translation is essential for rapid adaptation to changing environmental conditions, and also in some instances of hormonal control. General translational control, which affects all mRNAs, can target the initiation or the elongation step. General regulation of initiation commonly targets the translation initiation factors eIF2α or eIF4E; a common target for regulation of elongation is eEF-2. In all these cases, SAPK signalling has been shown to play a role. Posttranscriptional regulation of individual mRNAs is ultimately determined by cis-acting sequences, most famously the ARE sequences. SAPK’s are also implicated in translational control of individual mRNA species through ARE’s and probably other sequence elements. In addition, SAPK signalling can influence the use of alternative translation start sites, and transcription and mRNA stability of components of the protein synthesis machinery. While most knowledge of translational control is derived from mammalian systems, yeast genetics is recently providing complementary understanding.
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| 45. |
- Jansson, Kristina, 1969, et al.
(författare)
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A role for Myh1 in DNA repair after treatment with strand-breaking and crosslinking chemotherapeutic agents
- 2013
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Ingår i: Environmental and Molecular Mutagenesis. - : Wiley. - 0893-6692 .- 1098-2280. ; 54:5, s. 327-337
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Tidskriftsartikel (refereegranskat)abstract
- The highly conserved DNA glycosylase MutY is implicated in repair of oxidative DNA damage, in particular in removing adenines misincorporated opposite 7,8-dihydro-8-oxoguanine (8-oxo-G). The MutY homologues (MutYH) physically associate with proteins implicated in replication, DNA repair, and checkpoint signaling, specifically with the DNA damage sensor complex 9-1-1 proteins. Here, we ask whether MutYH could have a broader function in sensing and repairing different types of DNA damage induced by conventional chemotherapeutics. Thus, we examined if deletion of the Schizosaccharomyces pombe MutY homologue, Myh1, alone or in combination with deletion of either component of the 9-1-1 sensor complex, influences survival after exposure to different classes of DNA damaging chemotherapeutics that do not act primarily by causing 8-oxoG lesions. We show that Myh1 contributes to survival on genotoxic stresses induced by the oxidizing, DNA double strand break-inducing, bleomycins, or the DNA crosslinking platinum compounds, particularly in a rad1 mutant background. Exposure of cells to cisplatin leads to a moderate overall accumulation of Myh1 protein. Interestingly, we found that DNA damage induced by phleomycin results in increased chromatin association of Myh1. Further, we demonstrate that Myh1 relocalizes to the nucleus after exposure to hydrogen peroxide or chemotherapeutics, most prominently seen after phleomycin treatment. These observations indicate a wider role of Myh1 in DNA repair and DNA damage-induced checkpoint activation than previously thought
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| 46. |
- Jansson, Kristina, 1970, et al.
(författare)
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Evolutionary loss of 8-oxo-G repair components among eukaryotes
- 2010
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Ingår i: Genome Integrity. - 2041-9414. ; 1
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Tidskriftsartikel (refereegranskat)abstract
- Background We have examined the phylogenetic pattern among eukaryotes of homologues of the E. coli 7,8-dihydro-8-oxoguanine (8-oxo-G) repair enzymes MutY, MutM, and MutT. Results: These DNA repair enzymes are present in all large phylogenetic groups, with MutM homologues being the most universally conserved. All chordates and echinoderms were found to possess all three 8-oxo-G repair components. Likewise, the red and green algae examined have all three repair enzymes, while all land-living plants have MutY and MutM homologues, but lack MutT. However, for some phyla, e.g. protostomes, a more patchy distribution was found. Nematodes provide a striking example, where Caenorhabditis is the only identified example of an organism group having none of the three repair enzymes, while the genome of another nematode, Trichinella spiralis, instead encodes all three. The most complex distribution exists in fungi, where many different patterns of retention or loss of the three repair components are found. In addition, we found sequence insertions near or within the catalytic sites of MutY, MutM, and MutT to be present in some subgroups of Ascomycetes. Conclusion The 8-oxo-G repair enzymes are ancient in origin, and loss of individual 8 oxo G repair components at several distinct points in evolution appears to be the most likely explanation for the phylogenetic pattern among eukaryotes.
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| 47. |
- Jansson, Kristina, 1969, et al.
(författare)
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The tumor suppressor homolog in fission yeast, myh1+, displays a strong interaction with the checkpoint gene rad1
- 2008
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Ingår i: Mutation Research. - : Elsevier BV. ; 644, s. 48-55
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Tidskriftsartikel (refereegranskat)abstract
- The DNA glycosylase MutY is strongly conserved in evolution, and homologs are found in most eukaryotes and prokaryotes examined. This protein is implicated in repair of oxidative DNA damage, in particular adenine mispaired opposite 7,8-dihydro-8-oxoguanine. Previous investigations in Escherichia coli, fission yeast, and mammalian cells show an association of mutations in MutY homologs with a mutator phenotype and carcinogenesis. Eukaryotic MutY homologs physically associate with several proteins with a role in replication, DNA repair, and checkpoint signaling, specifically the trimeric 9-1-1 complex. In a genetic investigation of the fission yeast MutY homolog, myh1+, we show that the myh1 mutation confers a moderately increased UV sensitivity alone and in combination with mutations in several DNA repair genes. The myh1 rad1, and to a lesser degree myh1 rad9, double mutants display a synthetic interaction resulting in enhanced sensitivity to DNA damaging agents and hydroxyurea. UV irradiation of myh1 rad1 double mutants results in severe chromosome segregation defects and visible DNA fragmentation, and a failure to activate the checkpoint. Additionally, myh1 rad1 double mutants exhibit morphological defects in the absence of DNA damaging agents.We also found a moderate suppression of the slow growth and UV sensitivity of rhp51 mutants by the myh1 mutation. Our results implicate fission yeast Myh1 in repair of a wider range of DNA damage than previously thought, and functionally link it to the checkpoint pathway.
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| 48. |
- Johansson Sjölander, Johanna, 1980, et al.
(författare)
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The fission yeast FHIT homolog affects checkpoint control of proliferation and is regulated by mitochondrial electron transport.
- 2020
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Ingår i: Cell Biology International. - : Wiley. - 1095-8355 .- 1065-6995. ; 44:2, s. 412-423
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Tidskriftsartikel (refereegranskat)abstract
- Genetic analysis has strongly implicated human FHIT (Fragile Histidine Triad) as a tumor suppressor gene, being mutated in a large proportion of early-stage cancers. The functions of the FHIT protein have, however, remained elusive. Here, we investigated aph1+ , the fission yeast homolog of FHIT, for functions related to checkpoint control and oxidative metabolism. In sublethal concentrations of DNA damaging agents, aph1Δ mutants grew with a substantially shorter lag phase. In aph1Δ mutants carrying a hypomorphic allele of cds1 (the fission yeast homolog of Chk2), in addition, increased chromosome fragmentation and missegregation were found. We also found that under hypoxia or impaired electron transport function, the Aph1 protein level was strongly depressed. Previously, FHIT has been linked to regulation of the human 9-1-1 checkpoint complex constituted by Hus1, Rad1, and Rad9. In Schizosaccharomyces pombe, the levels of all three 9-1-1 proteins are all downregulated by hypoxia in similarity with Aph1. Moreover, deletion of the aph1+ gene reduced the Rad1 protein level, indicating a direct relationship between these two proteins. We conclude that the fission yeast FHIT homolog has a role in modulating DNA damage checkpoint function, possibly through an effect on the 9-1-1 complex, and that this effect may be critical under conditions of limiting oxidative metabolism and reoxygenation.
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| 49. |
- Kalenga, Thobias M, et al.
(författare)
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Antibacterial and cytotoxic biflavonoids from the root bark of Ochna kirkii
- 2021
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Ingår i: Fitoterapia. - : Elsevier BV. - 1873-6971 .- 0367-326X. ; 151
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Tidskriftsartikel (refereegranskat)abstract
- The new isoflavonoid kirkinone A (1) and biflavonoid kirkinone B (2) along with six known compounds (3-8) were isolated from the methanolic extract of the root bark of Ochna kirkii. The compounds were identified by NMR spectroscopic and mass spectrometric analyses. Out of the eight isolated natural products, calodenin B (4) and lophirone A (6) showed significant antibacterial activity against the Gram-positive bacterium Bacillus subtilis with MIC values of 2.2 and 28μM, and cytotoxicity against the MCF-7 human breast cancer cell line with EC50 values of 219.3 and 19.2μM, respectively. The methanolic crude extract of the root bark exhibited cytotoxicity at EC50 8.4μg/mL. The isolated secondary metabolites and the crude extract were generally inactive against the Gram-negative Escherichia coli (MIC ≥400μg/mL). Isolation of biflavonoids and related secondary metabolites from O. kirkii demonstrates their chemotaxonomic significance to the genus Ochna and to other members of the family Ochnaceae.
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| 50. |
- Kalenga, Thobias M, et al.
(författare)
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Biflavanones, Chalconoids, and Flavonoid Analogues from the Stem Bark of Ochna holstii.
- 2021
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 1520-6025 .- 0163-3864. ; 84:2, s. 364-372
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Tidskriftsartikel (refereegranskat)abstract
- Two new biflavanones (1 and 2), three new bichalconoids (3-5), and 11 known flavonoid analogues (6-16) were isolated from the stem bark extract (CH3OH-CH2Cl2, 7:3, v/v) of Ochna holstii. The structures of the isolated metabolites were elucidated by NMR spectroscopic and mass spectrometric analyses. The crude extract and the isolated metabolites were evaluated for antibacterial activity against Bacillus subtilis (Gram-positive) and Escherichia coli (Gram-negative) as well as for cytotoxicity against the MCF-7 human breast cancer cell line. The crude extract and holstiinone A (1) exhibited moderate antibacterial activity against B. subtilis with MIC values of 9.1 μg/mL and 14 μM, respectively. The crude extract and lophirone F (14) showed cytotoxicity against MCF-7 with EC50 values of 11 μg/mL and 24 μM, respectively. The other isolated metabolites showed no significant antibacterial activities (MIC > 250 μM) and cytotoxicities (EC50 ≥ 350 μM).
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