| 1. |
- Ekberg, Jenny, et al.
(författare)
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Expression of cyclin A1 and cell cycle proteins in hematopoietic cells and acute myeloid leukemia and links to patient outcome
- 2005
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Ingår i: European Journal of Haematology. - : Wiley-Blackwell Publishing Inc.. - 0902-4441 .- 1600-0609. ; 75:2, s. 106-115
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Tidskriftsartikel (refereegranskat)abstract
- Abnormal expression of several key regulators essential for G1/S transitions has been implicated in tumorigenesis. A critical role of cyclin A1 in the development of acute myeloid leukemia (AML) has previously been demonstrated in transgenic mice. Our present study focused on the expression and prognostic significance of cyclin A1 and a panel of cell cycle regulatory proteins including cyclin A2, cyclin B1, cyclin E, CDK1, CDK2, p21 and p27 in bone marrow samples from 40 patients with AML. Freshly isolated CD34+ hematopoietic cells and bone marrow samples from 10 healthy donors were also assessed for cell type- and subcellular-specific expression of the cell cycle regulatory proteins. The level of cyclin A1 expression was the only factor that showed a significant correlation with patient outcome. In log-rank test stratified by levels of cyclin A1 expression, patients with high levels of cyclin A1 had significantly worse overall survival (OS) (P = 0.012) compared to those with low levels. Further, patients with high levels of cyclin A1 had significantly lower disease-free survival (DFS) (P = 0.028). Multivariate analysis indicated that cyclin A1 protein expression was an independent prognostic factor for predicting DFS (P = 0.035) and OS (P = 0.045). No correlation between cyclin A1 expression and age was found. However, expression of cyclin A2, cyclin B1, cyclin E, CDK1, CDK2, p21 and p27 did not show prognostic significance in these AML patients.
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| 2. |
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| 3. |
- Ekberg, Jenny, et al.
(författare)
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Post-translational modification of cyclin A1 is associated with staurosporine and TNFalpha induced apoptosis in leukemic cells.
- 2009
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Ingår i: Molecular and Cellular Biochemistry. - : Springer Science and Business Media LLC. - 0300-8177 .- 1573-4919. ; 320:1-2, s. 115-24
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Tidskriftsartikel (refereegranskat)abstract
- Understanding of molecular mechanisms underlying the effects of cell cycle proteins in response to the chemotherapeutic agents is of great importance for improving the efficacy of targeted therapeutics and overcoming resistance to chemotherapeutic agents. Staurosporine and tumor necrosis factor alpha (TNFalpha) are the therapeutic agents that inhibit tumor cell growth by inducing cell death. Staurosporine induces apoptosis through the intrinsic pathway, while TNFalpha trigger the cell death via the extrinsic apoptotic pathway. We have previously demonstrated that the cell cycle regulatory protein, cyclin A1 played an important role in the development of acute myeloid leukemia (AML), and cyclin A1 expression correlated with disease characteristics and patient outcome in leukemia. However, it remains unknown how cyclin A1 expression is regulated in leukemic cells treated with the therapeutic agents. Here, we demonstrate that cyclin A1 protein is regulated by proteasome-mediated ubiquitination and degradation in untreated U-937 cells. Interestingly, ubiquitination- and proteasomal-mediated degradation of cyclin A1 is prevented in cells treated with staurosporine or TNFalpha. Induction of apoptosis in U-937 cells by staurosporine or TNFalpha resulted in an increase in cyclin A1 protein expression, which correlated well with cyclin A1 protein modification and the activation of caspase-3. Blocking caspases activity by Z-VAD-FMK had no effect on the increased cyclin A1 expression, suggesting that cyclin A1 might be regulated by caspase-3 independent pathways. We further propose that CDC25C may be associated with cyclin A1 protein modification in response to staurosporine or TNFalpha treatment. Our results suggest that cyclin A1 protein is stabilized via post-transcriptional modification in response to apoptosis induced by staurosporine or TNFalpha.
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| 4. |
- Ekberg, Jenny, et al.
(författare)
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Regulation of the cyclin A1 protein is associated with its differential subcellular localization in hematopoietic and leukemic cells
- 2004
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Ingår i: Oncogene. - : Nature Publishing Group. - 0950-9232 .- 1476-5594. ; 23:56, s. 9082-9089
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Tidskriftsartikel (refereegranskat)abstract
- An important role of the cell cycle regulatory protein cyclin A1 in the development of acute myeloid leukemia (AML) was previously demonstrated in a transgenic mouse model. We have now turned our attention to study specific aspects of the activity and subcellular distribution of cyclin A1 using bone marrow samples from normal donors and patients with AML, as well as leukemic cell lines. We show that the localization of cyclin A1 in normal hematopoietic cells is nuclear, whereas in leukemic cells from AML patients and cell lines, it is predominantly cytoplasmic. In leukemic cell lines treated with all-trans retinoic acid (ATRA), cyclin A1 localized to the nucleus. Further, there was a direct interaction between cyclin A1 and cyclin-dependent kinase 1, as well as a major ATRA receptor, RARalpha, in ATRA-treated cells but not in untreated leukemic cells. Our results indicate that the altered intracellular distribution of cyclin A1 in leukemic cells correlates with the status of the leukemic phenotype.
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| 5. |
- Wegiel, Barbara, et al.
(författare)
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A role for cyclin A1 in mediating the autocrine expression of vascular endothelial growth factor in prostate cancer
- 2005
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Ingår i: Oncogene. - : Nature Publishing Group. - 0950-9232 .- 1476-5594. ; 24:42, s. 6385-6393
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Tidskriftsartikel (refereegranskat)abstract
- Elevated levels of cyclin A1 expression have been implicated in acute myeloid leukemia and in male germ cell tumors. However, a role of cyclin A1 in tumorigenesis of prostate cancer has not been reported. In the present study, expression of cyclin A1 in patients with prostate cancer and a role of cyclin A1 in mediating expression of vascular endothelial growth factor (VEGF) were investigated. Cyclin A1 was highly expressed in aggressive tumors and was significantly correlated with VEGF expression in 96 patients with prostate cancer. Treatment of LNCaP cells with R1881, a synthetic androgen resulted in increased cyclin A1 expression. Induction of cyclin A1 expression in LNCaP cells led to an increase in VEGF expression and this effect was manifested upon the R1881 treatment. Cyclin A1 failed to mediate VEGF activation in DU-145 cells lacking a functional Rb and an androgen receptor (AR). Although AR expression was induced into DU-145 cells, cyclin A1 was unable to mediate VEGF expression. However, induced coexpression of cyclin A1, Rb and AR in DU-145 cells in the presence of R1881 greatly promoted VEGF promoter activity. This suggests that cyclin A1 mediates VEGF expression in cooperation with Rb- and androgen-dependent pathways in prostate cancer.
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| 6. |
- Wegiel, Barbara, et al.
(författare)
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The role of VEGF and a functional link between VEGF and p27Kip1 in acute myeloid leukemia
- 2009
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Ingår i: Leukemia. - : Nature Publishing Group. - 0887-6924 .- 1476-5551. ; 23:2, s. 251-61
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Tidskriftsartikel (refereegranskat)abstract
- Alterations in the expression and signalling pathways of vascular endothelial growth factor (VEGF) have been linked to the clinical features and pathogenesis of hematologic malignancies. In this study, we showed that VEGF protein expression was statistically significantly higher in the leukemic blasts than in the normal hematopoietic counterparts. A statistically significant correlation between expression of VEGF and p27(Kip1) was observed in bone marrows from 42 patients with acute myeloid leukemia (P<0.001). We further demonstrated that forced VEGF overexpression or autocrine VEGF stimulation of VEGFR-2 triggers proliferation and migration/invasion of U-937 leukemic cells, thereby inducing a more invasive tumor phenotype. U-937 cells overexpressing VEGF were resistant to all-trans-retinoic acid-(ATRA) or camptothecin-induced apoptosis. Finally, we showed that increased p27(Kip1) expression enhanced the ability of VEGF and VEGFR-2 to promote the migration of U-937 cells. Taken together, our results suggest that elevated level of VEGF may contribute to the adverse patient outcome by promoting cell growth, survival and migration of leukemic cells and by reducing the sensitivity of leukemic cells to therapeutic agents-induced apoptosis.
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| 7. |
- Ekberg, Jenny
(författare)
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Cyclin A1 Expression and Regulation in Hematopoietic and Leukemic Cells
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Increased expression of the cell cycle regulatory protein cyclin A1 has previously been detected in patients with acute myeloid leukemia (AML) and targeted overexpression of cyclin A1 in a transgenic mouse model initiated AML. The aim of this thesis was to further study the expression and regulation of cyclin A1 in hematopoietic cells. We started with evaluating the subcellular localization of cyclin A1 and found that the protein was localized to the nucleus of normal early hematopoietic cells while it had a cytoplasmic localization in leukemic bone marrow cells as well as in leukemic cell lines. We further found that treatment with all-trans retinoic acid (ATRA) resulted in nuclear localization of cyclin A1 in U-937 cells and in the formation of complex between cyclin A1, CDK1 and RAR?. Our results indicate that the cytoplasmic localization of cyclin A1 correlates with a leukemic phenotype. Next we continued with analyzing the clinical relevance of the increased cyclin A1 expression in 40 AML patients. We found that patients with high levels of cyclin A1 had a significantly worse overall survival and a significantly lower disease-free survival compared to patients with low levels of cyclin A1. We continued with analyzing the correlation between cyclin A1 and drug induced apoptosis. Induction of apoptosis using ATRA, staurosporine and TNF? resulted in significantly increased cyclin A1 protein levels in contrast to decreased levels of other cell cycle regulatory proteins. Interestingly, the increased protein levels did not result from increased protein synthesis but was rather a result from decreased ubiquitination and degradation. Further, upon overexpression of cyclin A1 a significant increased amount of apoptotic cells was found. Our results also suggest that there is an association between the post-translational modifications of cyclin A1 protein and the induction of apoptosis by therapeutic agents.
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| 8. |
- Funa, Nina, et al.
(författare)
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β-Catenin Regulates Primitive Streak Induction through Collaborative Interactions with SMAD2/SMAD3 and OCT4.
- 2015
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Ingår i: Cell Stem Cell. - : Elsevier BV. - 1934-5909. ; 16:6, s. 639-652
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Tidskriftsartikel (refereegranskat)abstract
- Canonical Wnt and Nodal signaling are both required for induction of the primitive streak (PS), which guides organization of the early embryo. The Wnt effector β-catenin is thought to function in these early lineage specification decisions via transcriptional activation of Nodal signaling. Here, we demonstrate a broader role for β-catenin in PS formation by analyzing its genome-wide binding in a human embryonic stem cell model of PS induction. β-catenin occupies regulatory regions in numerous PS and neural crest genes, and direct interactions between β-catenin and the Nodal effectors SMAD2/SMAD3 are required at these regions for PS gene activation. Furthermore, OCT4 binding in proximity to these sites is likewise required for PS induction, suggesting a collaborative interaction between β-catenin and OCT4. Induction of neural crest genes by β-catenin is repressed by SMAD2/SMAD3, ensuring proper lineage specification. This study provides mechanistic insight into how Wnt signaling controls early cell lineage decisions.
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| 9. |
- Halleröd, Jenny, 1987, et al.
(författare)
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Development of the Chalmers grouped actinide extraction process
- 2015
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Ingår i: Nukleonika. - : Walter de Gruyter GmbH. - 1508-5791 .- 0029-5922. ; 60:4, s. 829-835
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Tidskriftsartikel (refereegranskat)abstract
- Several solvents for Grouped ActiNide EXtraction (GANEX) processes have been investigated at Chalmers University of Technology in recent years. Four different GANEX solvents; cyclo-GANEX (CyMe4--BTBP, 30 vol.% tri-butyl phosphate (TBP) and cyclohexanone), DEHBA-GANEX (CyMe4-BTBP, 20 vol.% N,N-di-2(ethylhexyl) butyramide (DEHBA) and cyclohexanone), hexanol-GANEX (CyMe4-BTBP, 30 vol.% TBP and hexanol) and FS-13-GANEX (CyMe4-BTBP, 30 vol.% TBP and phenyl trifluoromethyl sulfone (FS-13)) have been studied and the results are discussed and compared in this work. The cyclohexanone based solvents show fast and high extraction of the actinides but a somewhat poor diluent stability in contact with the acidic aqueous phase. FS-13-GANEX display high separation factors between the actinides and lanthanides and a good radiolytic and hydrolytic stability. However, the distribution ratios of the actinides are lower, compared to the cyclohexanone based solvents. The hexanol-GANEX is a cheap solvent system using a rather stable diluent but the actinide extraction is, however, comparatively low.
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| 10. |
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