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| 2. |
- Alzrigat, Mohammad
(författare)
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Targeted Inhibition of Polycomb Repressive Complexes in Multiple Myeloma : Implications for Biology and Therapy
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Multiple myeloma (MM) is a hematological malignancy of antibody producing plasmablasts/plasma cells. MM is characterized by extensive genetic and clonal heterogeneity, which have hampered the attempts to identify a common underlying mechanism for disease establishment and development of appropriate treatment regimes. This thesis is focused on understanding the role of epigenetic regulation of gene expression mediated by the polycomb repressive complexes 1 and 2 (PRC1 and 2) in MM and their impact on disease biology and therapy.In paper I the genome-wide distribution of two histone methylation marks; H3K27me3 and H3K4me3 were studied in plasma cells isolated from newly diagnosed MM patients or age-matched normal donors. We were able to define targets of H3K27me3, H3K4me3 and bivalent (carry both marks) which are, when compared to normal individuals, unique to MM patients. The presence of H3K27me3 correlated with silencing of MM unique H3K27me3 targets in MM patients at advanced stages of the disease. Notably, the expression pattern of H3K27me3-marked genes correlated with poor patient survival. We also showed that inhibition of the PRC2 enzymatic subunit EZH2 using highly selective inhibitors (GSK343 and UNC1999) demonstrated anti-myeloma activity using relevant in vitro models of MM. These data suggest an important role for gene repression mediated by PRC2 in MM, and highlights the PRC2 component EZH2 as a potential therapeutic target in MM.In paper II we further explored the therapeutic potential of UNC1999, a highly selective inhibitor of EZH2 in MM. We showed that EZH2 inhibition by UNC1999 downregulated important MM oncogenes; IRF-4, XBP-1, BLIMP-1and c-MYC. These oncogenes have been previously shown to be crucial for disease establishment, growth and progression. We found that EZH2 inhibition reactivated the expression of microRNAs genes previously found to be underexpressed in MM and which possess potential tumor suppressor functions. Among the reactivated microRNAs we identified miR-125a-3p and miR-320c as predicted negative regulators of the MM-associated oncogenes. Notably, we defined miR-125a-3p and miR-320c as targets of EZH2 and H3K27me3 in MM cell lines and patients samples. These findings described for the first time PRC2/EZH2/H3K27me3 as regulators of microRNA with tumor suppressor functions in MM. This further strengthens the oncogenic features of EZH2 and its potential as a therapeutic target in MM.In paper III we evaluated the therapeutic potential of targeting PRC1 in MM using the recently developed chemical PTC-209; an inhibitor targeting the BMI-1 subunit of PRC1. Using MM cell lines and primary cells isolated from newly diagnosed or relapsed MM patients, we found that PTC-209 has a potent anti-MM activity. We showed, for the first time in MM, that PTC-209 anti-MM effects were mediated by on-target effects i.e. downregulation of BMI-1 protein and the associated repressive histone mark H2AK119ub, but that other subunits of the PRC1 complex were not affected. We showed that PTC-209 reduced MM cell viability via significant induction of apoptosis. More importantly, we demonstrated that PTC-209 shows synergistic anti-MM activity with other epigenetic inhibitors targeting EZH2 (UNC1999) and BET-bromodomains (JQ1). This work highlights the potential use of BMI-1 and PRC1 as potential therapeutic targets in MM alone or in combination with other anti-MM agents including epigenetic inhibitors.
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| 3. |
- Johansson, Mattias, 1977-
(författare)
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Prostate cancer aetiology : epidemiological studies of the IGF- and one-carbon metabolism pathways
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis was to investigate the involvement of the insulin-like growth factor- and the one-carbon metabolism pathways in prostate cancer aetiology, studying both circulating biomarkers and genetic variation. Papers included in the thesis were conducted within the case-control study CAncer Prostate in Sweden (CAPS), and the two prospective studies European Prospective Investigation into nutrition and Cancer (EPIC), and Northern Sweden Health and Disease Cohort (NSHDC).In paper I, we investigated the relation between genetic variants of the IGF1 gene and prostate cancer risk within the CAPS study. We found that a common haplotype within the 3’ region of the IGF1 gene is associated with increased prostate cancer risk.In paper II, we investigated if the variants of the IGF1 gene that were associated with prostate cancer risk in paper I, are also associated with circulating levels of IGF1. Circulating levels of IGF1 were analysed in controls from the CAPS study and three haplotype tagging SNPs (htSNPs) were genotyped in subjects from the NSHDC study in which circulating IGF1 had previously been analysed. The genetic variants previously associated with increased prostate cancer risk were now also found to be associated with elevated levels of circulating IGF1. We concluded that variation in the 3’ region of the IGF1 gene affects prostate cancer risk by influencing circulating levels of IGF1.In paper III, we investigated if variants of the IGFBP1, IGFBP3 and IGFALS genes are associated with i) prostate cancer risk, ii) circulating concentrations of total and intact IGFBP3, and iii) prostate cancer-specific survival probability. In addition, we investigated if circulating concentrations of total and intact IGFBP3 are associated with prostate cancer-specific survival probability. No association between genetic variation and overall prostate cancer risk or survival was observed, but we found a strong association between elevated levels of intact IGFBP3 and increased risk of prostate cancer-specific death. We could, however, not exclude that this association was confounded by treatment or by the tumour.In paper IV, we investigated if circulating levels of folate and vitamin B12 are associated with prostate cancer risk within the EPIC study. We observed no associations between levels of folate, vitamin B12 and overall prostate cancer risk, but elevated levels of vitamin B12 were associated with increased risk of advanced stage disease.In paper V, we investigated if circulating levels of ten B-vitamins and related metabolites within the one-carbon metabolism pathway are associated with prostate cancer risk within the NSHDC study. Overall positive associations with prostate cancer risk were observed for levels of choline, vitamin B2 and vitamin B12, and inverse associations were observed for levels of homocysteine and MMA. We also observed a biologically plausible risk modification by smoking status on the association between vitamin B12 and risk; in non-smokers vitamin B12 was positively associated with risk, whereas the association between vitamin B12 and risk was inverse or null in ever/current-smokers.In summary, our results suggest that genetic variation of the IGF1 gene affects prostate cancer risk by affecting circulating levels of IGF1. The association between circulating concentrations of intact IGFBP3 and prostate cancer-specific survival is intriguing, but further studies are needed to conclude if this association is caused by confounding. We also observed associations between several factors of one-carbon metabolism and risk, but these associations were statistically week and require confirmation in other prospective studies.
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| 4. |
- Kalushkova, Antonia
(författare)
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Epigenetic gene regulation in multiple myeloma and mood disorders
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Epigenetics continues to be redefined and new discoveries are likely to revolutionise the field still further. This thesis explores different aspects of how epigenetic regulation of gene expression contributes to human disease.Paper I explores the function of the IKKα kinase in regulating gene expression through the nuclear retinoic acid receptor (RAR). We define a set of genes requiring IKKα for their expression and found recruitment of IKKα to the RAR dependent on structural motifs in its protein sequence. This interplay between the NFκB pathway and nuclear receptor regulated transcription is important to consider when designing therapeutic strategies.Papers II and III focus on the plasma cell malignancy multiple myeloma (MM) and define a gene regulatory circuit defining an underexpressed gene profile in MM dependent on the Polycomb proteins. We provide proof-of-principle that the use of small chemical inhibitors may be operational in reactivating genes silenced by H3K27me3 and that this leads to decreased tumour load and increased survival in the 5T33 in vivo model of MM. We explored the genome-wide distribution of H3K27me3 and H3K4me3, and defined their association with gene expression in freshly-isolated malignant plasma cells from MM patients. Importantly, H3K27me3-marked genes in MM associated with more aggressive stages of the disease and less favourable survival. We present evidence that gene targeting by H3K27me3 is likely to not only involve a small population of tumour cells, but rather represent a common MM profile and further provide a rationale for evaluating epigenetic therapeutics in MM.Paper IV shows that pro-inflammatory gene expression in monocytes of psychiatric patients can be induced in vitro by sodium pump inhibitors, as the steroid hormone ouabain. We suggest that the ouabain-induced gene expression is regulated by an intricate network involving microRNAs, Polycomb and the H3K27me3 demethylase JMJD3. Our data indicates that epigenetic regulators play a role in transmitting cues between intrinsic and/extrinsic stimuli and gene expression in psychiatric illness.This thesis provides novel insights on how seemingly unrelated pathways may converge on transcriptional regulation and evidence that epigenetic modifiers contribute to the pathogenesis of human complex diseases such as multiple myeloma and mood disorders.
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| 5. |
- Lindström, Sara, 1979-
(författare)
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Genetic variation and prostate cancer : population-based association studies in Sweden
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Prostate cancer constitutes the most common malignancy and the most common cause of cancer‐related death in Swedish men. A large body of evidence suggests that inherited genetic variants contribute to both development and progression of prostate cancer. The aim of this thesis is to identify genetic variants that alter prostate cancer risk and progression. All papers included in this thesis are based on a Swedish population‐based case‐control study (CAPS) comprising 2,965 incident prostate cancer cases and 1,823 controls.In paper I, we investigated if genetic variants in the E‐cadherin gene altered prostate cancer risk. Seven haplotype tagging SNPs(tagSNPs) were selected and genotyped in CAPS and families with hereditary prostate cancer. We confirmed association of a promoter SNP rs16260 previously reported to increase risk of hereditary prostate cancer (OR: 2.6; 95% CI: 1.6‐4.3) for homozygous ‘A’ carriers.In paper II, we assessed 46 polymorphisms earlier reported to be associated with prostate cancer risk. Six polymorphisms in five different genes were replicated. Interestingly, three of these genes were involved in the androgen biosynthesis.In paper III, we followed up on the results from paper II by genotyping 23 tagSNPs located in the hormone regulating genes AR, CYP17 and SRD5A2. Multiple SNPs and haplotypes were associated withprostate cancer risk, especially in the AR gene. Combining risk alleles from all genes revealed a substantial risk increase for each additional allele carried (OR: 1.12; 95% CI: 1.1‐1.2, P=0.00009).In paper IV, we collected information about cause of death for all case patients in CAPS. At time of follow‐up 300 study subjects were deceased from prostate cancer. We assessed AR, CYP17 and SRD5A2 variants for association with lethal prostate cancer and found overall no association. However, one AR promoter SNP was associated with an increased risk of dying from prostate cancer amongst men who received palliative hormonal therapy as primary treatment.In paper V, we assessed common genetic variation at the ERG locus for association between prostate cancer risk and survival. ERG is recognized as a protooncogene frequently overexpressed in prostate cancer. A total of 21 tagSNPs in the 5’ region of ERG were genotyped. There was no correlation between ERG SNPs and prostate cancer risk but common genetic variation located approximately 100,000 basepairs upstream of ERG was significantly associated with prostate cancer specific survival.In summary, our results suggest that common genetic variation in Ecadherin alters prostate cancer risk in Swedish men with a positive family history of prostate cancer. Moreover, common genetic variation in the androgen‐related genes AR, CYP17 and SRD5A2 affects the risk of developing prostate cancer but is unlikely to alter prostate cancer progression. However, genetic variants in AR may affect hormonal therapy response. Finally, ERG polymorphisms are associated with prostate cancer‐specific death but are not likely to play a role in prostate cancer development.
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| 6. |
- Månsson, Linda, 1973-
(författare)
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Digital fall prevention for older adults : Feasibility of a self-managed exercise application and development of a smartphone self-test for balance and leg strength
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As the numbers of older adults grow, fall prevention is vital to reduce health care needs due to falls and to increase quality of life. Balance and strength exercises have been found to be effective in fall prevention, however, long-term adherence is often poor. The growth of digital technology in society has generated opportunities for fall prevention with eHealth. The aim of this thesis was to evaluate the feasibility and use of a new digital fall prevention exercise programme, and to develop and investigate a smartphone self-test application for balance and leg strength. Three different studies included community-dwelling older adults ≥ 70 years, who were able to rise from a chair and stand without support. A feasibility study evaluated a new digital exercise programme (DP) compared to a paper booklet exercise programme (PB) for self-managed fall prevention in a four-month controlled participant preference trial (n = 67) (Paper I & II). Self-reported data on adherence, falls efficacy, and functional ability were collected and analysed, along with performance-based measures of gait speed, balance, and chair stand test. In Paper II the feasibility was explored of using the self-reported scales and performance-based outcome measures. A self-test application was also developed (Paper III) in co-creation with 10 participants, who met during five sessions to design the application’s instructions and user interface. The participants’ preference for and their contribution to the application design was analysed with qualitative content analysis with a deductive-inductive approach. A concurrent validity study (n = 31) (Paper IV) assessed the correlations between variables from the self-test prototype and outcome measures from clinical instruments. Results from the feasibility study show that 43% chose the DP and 57% PB, and the attrition rate was 17% and 37% respectively. Both groups had similar adherence, but for the subgroup that exercised most, participants in the DP group reported significantly more exercise time (Paper I). Participants in both groups reported a boost in balance after the intervention, and in the DP group also improved leg strength. Significantly more participants continued to use the DP at 12 months. The self-managed exercise intervention (Paper II) resulted in improvements in functional leg strength, which positively correlated with exercise time, but no other performance-based outcomes showed any significant improvements. Performance-based measurements of balance as well as the self- reported balance confidence and fear of falling revealed ceiling effects. Pre-assessments of self-reported outcomes and performance-based measures showed significant but low correlations, no such correlations were seen in change scores. The deductive-inductive analysis of the co-creation process resulted in 17 subcategories within the seven facets of the Optimized Honeycomb model for iii user experience (Paper III). The main results were that participants desired clear and appropriate information to understand why things were done in a certain way, and their contributions enhanced the user experience of the self-test. The concurrent validity testing of the self-test prototype (IV) showed low to moderate correlations for the strength test but limited correlations for the balance test. In conclusion the DP group showed comparable adherence to the programme as the PB group, as well as to previous studies, indicating it was feasible to use the new DP. DP participants also reported better exercise maintenance after 12 months. Positive self-reported effects were expressed in addition to leg strength improvement. Outcome measures for balance and falls efficacy revealed ceiling effects, consequently, these instruments might not be suitable for assessments in all community-dwelling older adults. In particular, for balance related outcomes there is a need for new more sensitive measurements. The co-creation of the smartphone self-test was feasible and valuable for user experience, but further validity and reliability testing are needed before it can serve as an independent assessment tool.
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| 7. |
- Nylund, Patrick
(författare)
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Targeting molecular mechanisms for epigenetic silencing in multiple myeloma : Implications for biology and precision medicine
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Multiple myeloma (MM) is a heterogeneous haematological cancer where malignant plasma cells clonally expand within the bone marrow. The transcriptional repressor PRC2 and its catalytic subunit EZH2 play a major role in MM, as PRC2 re-targeting results in a MM-specific gene silencing profile. In paper I, we explored the metabolic response to EZH2 inhibition (EZH2i). A global loss of H3K27me3 was found in all EZH2i-treated MM cell lines. EZH2i-sensitive cell lines acquired a unique metabolic signature, following the upregulation of a cluster of miRNAs which target methionine cycling-associated genes and are silenced by H3K27me3. These miRNAs were not upregulated in resistant cell lines, due to additional DNA methylation-mediated silencing.Therefore, in paper II we sought to evaluate the combinatorial effect of DNA demethylation agents and EZH2 inhibitors. Here, we provided a comprehensive map of the reconfiguration of the epigenome in primary MM samples. Furthermore, we demonstrated a direct protein-protein interaction between DNMT1 and EZH2 and showed that co-inhibition of these enzymes has an enhanced effect in synergistically activating genes regulating apoptosis and cell cycling. PRC2 lacks sequence specificity but contains a lncRNA binding pocket. In paper III, we hypothesized that PRC2 targeting to specific genomic regions could be mediated by lncRNAs in the context of MM. Coupling RIP- and RNA-seq, we identified a physical interaction between the lncRNA PVT1 and EZH2, as well as 270 genes potentially targeted by the EZH2-PVT1 axis. In addition, we found that independent inhibition of EZH2 and PVT1 resulted in the upregulation of the tumour suppressor genes ZBTB7C, RNF144A and CCDC136, suggesting a functional interdependency between these two epigenetic regulators. In paper IV we investigated the effects of dual G9a/DNMT inhibition in MM cells, resulting in suppressed expression of MM-associated oncogenes and increased tumour cell death. By coupling ChIP-seq, DNA methylation arrays and RNA-seq, we identified a group of genes silenced by G9a and/or DNMTs that when activated, blocked MM proliferative potential by activating genes with tumour suppressor function. In summary, this thesis highlights the strong interconnection between the dysregulation of epigenetic/metabolic regulatory mechanisms and MM pathogenesis, providing insights into how these mechanisms can be targeted to promote anti-MM effects.
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| 8. |
- Párraga, Alba Atienza, 1988-
(författare)
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The Epigenome of Multiple Myeloma : From genome-wide analysis to pharmacological manipulation
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Nowadays epigenetic dysregulation is known to play a crucial role in virtually all cancers. In multiple myeloma (MM), an extensively heterogeneous malignancy, the key common feature among patients is the gene silencing imposed by the PRC2 complex through the addition of H3K27me3. This thesis focuses on the exploration of the MM epigenomic landscape, with an emphasis on both the interplay between H3K27me3 and other epigenetic tags, and on the effects of a series of inhibitors altering this profile.In paper I we provide the genome-wide H3K27me3 distribution unique to MM and demonstrate that the silencing of genes in the profile correlates with an advanced and poor-outcome disease. Reduction of H3K27me3 using the EZH2 inhibitor UNC1999 reactivates genes with anti-tumor activity and induces apoptosis in vitro.EZH2 inhibition also leads to downregulation of the MM oncogenes IRF-4, BLIMP-1, XBP-1 and c-MYC. Paper II identifies miR-125a-3p and miR-320c, predicted to target these oncogenes, as part of the PRC2 targets induced upon treatment.In addition, H3K27me3 can be recognized and bound by the PRC1 complex. In paper III we show that inhibition of PRC1 using PTC-209 induces apoptosis and this is further enhanced when PTC-209 is combined with UNC1999. Moreover, PTC-209 has been previously shown to reduce the expression of c-MYC. Combined treatment using PTC-209 and JQ1, demonstrated to downregulate c-MYC, results in additive and synergistic effects in reducing MM cell viability.In paper IV we present the first catalogue of genomic regulatory regions in normal plasma cells, as predicted by their combinations of histone marks. Using this, we demonstrate that in MM a subset of TSSs and enhancers become targeted by H3K27me3 and display high DNA methylation, pointing towards a possible silencing. Conversely, poised TSSs lose H3K27me3 and seemingly become de novo activated. Furthermore, we show that EZH2 physically interacts with the DNA methyltransferase DNMT1 and that combined inhibition using UNC1999 and the DNA hypomethylating agent AZA blocks the G2/M arrest triggered by AZA and induces apoptosis.In summary, this thesis highlights the complex interconnectivity of epigenetic mechanisms in MM and provides proof-of-principle of the anti-MM effects derived from inhibiting epigenetic components in single or combinatorial regimens.
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| 9. |
- Stjernholm, Fredrik, 1973-
(författare)
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Allocation of body resources to reproduction in butterflies
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The life-history of an organism can be studied and understood in terms of acquisition and expenditure of resources. In butterflies, the use of resources for reproduction has been the focus of much research due to the possibility to easily quantify both the input of resources from different sources over the life-cycle as well as the partitioning of these resources to reproduction. In the first part of my thesis we studied how the pattern of partitioning of resources between somatic tissue, such as muscles, wings and exoskeleton, and storage of resources for reproductive purposes during metamorphosis affects reproduction. Theory predicts that reproduction should be strongly dependent on the relative investments in soma and reproductive reserves, but this has generally proven difficult to show empirically. Butterflies are eminently suited for testing this prediction, and our results show that fecundity of female comma butterflies (Polygonia c-album) is strongly influenced by allocation priorities. One aspect of resource use that has not attracted attention until recently is the possibility that butterflies during the reproductive stage can break down flight muscles in the thorax and use muscle nutrients for reproduction. Since butterflies are generally resource limited this could alleviate the costs resulting from somatic investment found in paper I. Through a series of studies we show that thorax mass and nitrogen content decreases over the adult lifespan in a manner consistent with the hypothesis that thorax resources are used for reproduction. In order to determine if these resources could actually come from the flight muscles, something that is known to occur in other insects, the reduction in flight muscle size over the lifespan was studied in the green-veined white butterfly (Pieris napi). The results showed that flight muscle size decreased with on average 75% in long-lived females, suggesting that breakdown of flight muscles could indeed influence reproduction. Taken together, the work in this thesis shows that resource allocation during metamorphosis strongly influences the reproductive potential, but that butterflies can overcome some of the costs of somatic investment by reallocating resources from thoracic tissue to reproduction.
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| 10. |
- Wiklund, Fredrik, 1963-
(författare)
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Genetic epidemiology of prostate cancer
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Prostate cancer is a major health burden throughout the world, yet the etiology of prostate cancer is poorly understood. Evidence has accumulated supporting the existence of a hereditary form of this disease. Improved understanding of the genetic mechanisms underlying the development and progression of prostate cancer would be a major advance for improved prevention, detection and treatment strategies. This thesis evaluates different aspects of the genetic epidemiology of prostate cancer. In a genomic scan two chromosomal regions with evidence for linkage was observed. The strongest support was found on chromosome 19p with an allele sharing LOD score of 2.91 (genome-wide P = 0.032). The second region, showing suggestive evidence of linkage, was observed in the centromeric region of chromosome 5. Linkage analyses of densely spaced markers on chromosome 8p22-23 confirmed (P = 0.03) previously reported linkage to this region. A systematic evaluation of the possible impact that the RNASEL gene have on prostate cancer was performed. Overall, limited evidence for association with prostate cancer risk was found. The results provide strong evidence against a role of RNASEL in prostate cancer etiology in Sweden. In a comprehensive evaluation of occurrence of other malignancies in HPC families, previously reported association between gastric and prostate carcinoma was confirmed. The increased risk was of the same magnitude in early and late onset HPC families and confined to only male relatives. A genome-wide linkage analysis, stratified by occurrence of gastric carcinoma, identified a novel susceptibility locus on chromosome Xp21. In summary, chromosome 5q and 19p represents the regions most likely to harbor susceptibility genes predisposing to prostate cancer in the Swedish population. A common genetic basis for both gastric and prostate cancer has been confirmed and a novel susceptibility locus on chromosome Xp21 has been identified.
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