| 1. |
- Samuelson, Emma, 1974, et al.
(author)
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Absence of Ras mutations in rat DMBA-induced mammary tumors.
- 2009
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In: Molecular carcinogenesis. - : Wiley. - 1098-2744 .- 0899-1987. ; 48:2, s. 150-5
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Journal article (peer-reviewed)abstract
- Animal cancer models reduce genetic background heterogeneity and thus, may facilitate identification and analysis of specific genetic aberrations in tumor cells. Rat and human mammary glands have high similarity in physiology and show comparable hormone responsiveness. Thus, spontaneous and carcinogen (e.g., NMU and DMBA)-induced rat mammary models are valuable tools for genetic studies of breast cancer. In NMU-induced rat mammary tumors, activating mutations in Hras codon 12 have frequently been reported and are supposed to contribute to the mammary carcinogenic process. Involvement of Ras mutations in DMBA-induced tumors is less clear. In the present study we investigated the mutation status of the three Ras genes, Hras, Kras, and Nras, in DMBA-induced rat mammary tumors. We examined codons 12, 13, and 61 of all three genes for mutations in 71 tumors using direct sequencing method that in experimental conditions is sensitive enough to detect single nucleotide mutations even when present in only 25% of the test sample. No activating Ras gene mutation was found. Thus, in contrast to NMU-induced rat mammary tumor, tumorigenesis in DMBA-induced rat mammary tumors seems to be independent on activating mutations in the Ras genes. Our finding suggests that the genetic pathways selected in mammary tumor development are influenced by and perhaps dependent on the identity of the inducing agent, again emphasizing the importance of tumor etiology on the genetic changes in the tumor cells.
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| 2. |
- Samuelson, Emma, et al.
(author)
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Molecular classification of spontaneous endometrial adenocarcinomas in BDII rats
- 2009
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In: Endocrine-Related Cancer. - : Bioscientifica. - 1351-0088 .- 1479-6821. ; 16:1, s. 99-111
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Journal article (peer-reviewed)abstract
- Female rats of the BDII/Han inbred strain are prone to spontaneously develop endometrial carcinomas (EC) that in cell biology and pathogenesis are very similar to those of human. Human EC are classified into two major groups: Type I displays endometroid histology, is hormone-dependent, and characterized by frequent microsatellite instability and PTEN, K-RAS, and CTNNB1 (β-Catenin) mutations; Type II shows non-endometrioid histology, is hormone-unrelated, displays recurrent TP53 mutation, CDKN2A (P16) inactivation, over-expression of ERBB2 (Her2/neu), and reduced CDH1 (Cadherin 1 or E-Cadherin) expression. However, many human EC have overlapping clinical, morphologic, immunohistochemical, and molecular features of types I and II. The EC developed in BDII rats can be related to type I tumors, since they are hormone-related and histologically from endometrioid type. Here, we combined gene sequencing (Pten, Ifr1, and Ctnnb1) and real-time gene expression analysis (Pten, Cdh1, P16, Erbb2, Ctnnb1, Tp53, and Irf1) to further characterize molecular alterations in this tumor model with respect to different subtypes of EC in humans. No mutation in Pten and Ctnnb1 was detected, whereas three tumors displayed sequence aberrations of the Irf1 gene. Significant down regulation of Pten, Cdh1, p16, Erbb2, and Ctnnb1 gene products was found in the tumors. In conclusion, our data suggest that molecular features of spontaneous EC in BDII rats can be related to higher-grade human type I tumors and thus, this model represents an excellent experimental tool for research on this malignancy in human.
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| 3. |
- Tajsharghi, Homa, 1968, et al.
(author)
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A Caenorhabditis elegans model of the myosin heavy chain IIa E706R mutation.
- 2005
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In: Annals of Neurology. - : Wiley. - 0364-5134 .- 1531-8249. ; 58:3, s. 442-448
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Journal article (peer-reviewed)abstract
- Mutations in myosin heavy chain (MyHC) genes recently have been shown to be associated with various forms of congenital myopathies: myosin myopathies. The MyHC IIa E706K mutation is associated with congenital joint contractures, early-onset muscle weakness, and progressive course with moderate to severe muscle weakness later in life. To study the pathogenicity of this MyHC mutation, we investigated the effect of the corresponding mutation (E710K) in the major MyHC isoform (MyHC B) of the body wall muscle of the nematode Caenorhabditis elegans. Worms with null mutations in the MyHC B gene (unc-54) are severely paralyzed and depleted of thick filaments in the body wall muscle sarcomeres. unc-54 null mutants with extrachromosomal arrays of a gene construct including the entire wild-type unc-54 gene were partially rescued as determined by a motility assay and by morphological analysis of the body wall muscle. Analysis of unc-54 null mutants with extrachromosomal arrays of the unc-54 gene with the E710K mutation were severely paralyzed but showed formation of thick filaments in the body wall muscle. We conclude that the MyHC E706K (E710K in C. elegans) mutation is pathogenic and that the effect is primarily functional rather than structural because thick filaments are formed. The C. elegans model may be useful to study suspected pathogenic mutations in MyHC genes associated with human muscle diseases. Ann Neurol 2005;58:442-448.
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| 4. |
- Krettek, Alexandra, 1968, et al.
(author)
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CD44 - a new cardiovascular drug target or merely an innocent bystander?
- 2009
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In: Cardiovascular & hematological disorders drug targets. - : ingentaconnect. - 2212-4063. ; 9:4, s. 293-302
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Journal article (peer-reviewed)abstract
- CD44, short for cluster of differentiation 44, is an adhesion molecule of the hyaluronate receptor family. Expressed on the surface of most vertebrate cells, it functions as a receptor for several extracellular matrix components, e.g., hyaluronan, collagen, laminin, fibronectin, and osteopontin. CD44 has in recent years been intensively studied in connection with different forms of cancer, where CD44 may regulate invasiveness and tumor progression. Although major functions involve adhesion and migration, CD44 also affects leukocyte homing and recruitment, phagocytosis, matrix remodeling, proliferation, and apoptosis. As such, CD44 is an interesting putative molecule in cardiovascular drug therapy. Accumulating evidence from human studies point to CD44 as involved in inflammatory diseases such as atherosclerosis and human abdominal aneurysms. To date, several animal studies have shown that the role of CD44 in atherogenesis may vary depending on experimental model. In this Review, we trace CD44 and its potential role in the context of cardiovascular diseases by highlighting both human and animal studies that may help us understand; is CD44 a new cardiovascular drug target or merely an innocent bystander?
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| 5. |
- Rune, A., et al.
(author)
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Evidence against a sexual dimorphism in glucose and fatty acid metabolism in skeletal muscle cultures from age-matched men and post-menopausal women
- 2009
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In: Acta Physiologica. - : Wiley. - 1748-1708 .- 1748-1716. ; 197:3, s. 207-215
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Journal article (peer-reviewed)abstract
- Aim: In vivo whole body differences in glucose/lipid metabolism exist between men and women. Thus, we tested the hypothesis that intrinsic sex differences exist in skeletal muscle gene expression and glucose/lipid metabolism using cultured myotubes. Methods: Myotube cultures were prepared for gene expression and metabolic studies from vastus lateralis skeletal muscle biopsies obtained from age-matched men (n = 11; 59 +/- 2 years) and post-menopausal women (n = 10; 60 +/- 1 years). Results: mRNA expression of several genes involved in glucose and lipid metabolism was higher in skeletal muscle biopsies from female vs. male donors, but unaltered between the sexes in cultured myotubes. Basal and insulin-stimulated glucose uptake, as well as glucose incorporation into glycogen, was similar in myotube cultures derived from male vs. female donors. In males vs. females, insulin increased glucose uptake (1.3 +/- 0.1 vs. 1.5 +/- 0.1-fold respectively) and incorporation into glycogen (2.3 +/- 0.3 vs. 2.0 +/- 0.3-fold respectively) to the same extent. Basal fatty acid oxidation and rate of uptake/accumulation was similar between sexes. In response to the 5'AMP-activated protein kinase activator AICAR, lipid oxidation was increased to the same extent in myotubes established from male vs. female donors (1.6 +/- 0.6 vs. 2.0 +/- 0.3-fold respectively). Moreover, the AICAR-induced rate of uptake/accumulation was similar between sexes. Conclusion: Differences in metabolic parameters and gene expression profiles between age-matched men and post-menopausal women noted in vivo are not observed in cultured human skeletal muscle cells. Thus, the sexual dimorphism in glucose and lipid metabolism is likely a consequence of systemic whole body factors, rather than intrinsic differences in the skeletal muscle proper.
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| 6. |
- Fagman, Johan Bourghardt, 1980, et al.
(author)
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The endogenous estradiol metabolite 2-methoxyestradiol reduces atherosclerotic lesion formation in female apolipoprotein E-deficient mice
- 2007
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In: Endocrinology. - : Endocrine Society. - 0013-7227 .- 1945-7170. ; 148:9, s. 4128-4132
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Journal article (peer-reviewed)abstract
- Estradiol, the major endogenous estrogen, reduces experimental atherosclerosis and metabolizes to 2-methoxyestradiol in vascular cells. Currently undergoing evaluation in clinical cancer trials, 2-methoxyestradiol potently inhibits cell proliferation independently of the classical estrogen receptors. This study examined whether 2-methoxyestradiol affects atherosclerosis development in female mice. Apolipoprotein E-deficient mice, a well-established mouse model of atherosclerosis, were ovariectomized and treated through slow-release pellets with placebo, 17beta-estradiol (6 microg/d), or 2-methoxyestradiol [6.66 microg/d (low-dose) or 66.6 microg/d (high-dose)]. After 90 d, body weight gain decreased and uterine weight increased in the high-dose but not low-dose 2-methoxyestradiol group. En face analysis showed that the fractional area of the aorta covered by atherosclerotic lesions decreased in the high-dose 2-methoxyestradiol (52%) but not in the low-dose 2-methoxyestradiol group. Total serum cholesterol levels decreased in the high- and low-dose 2-methoxyestradiol groups (19%, P < 0.05 and 21%, P = 0.062, respectively). Estradiol treatment reduced the fractional atherosclerotic lesion area (85%) and decreased cholesterol levels (42%). In conclusion, our study shows for the first time that 2-methoxyestradiol reduces atherosclerotic lesion formation in vivo. The antiatherogenic activity of an estradiol metabolite lacking estrogen receptor activating capacity may argue that trials on cardiovascular effects of hormone replacement therapy should use estradiol rather than other estrogens. Future research should define the role of 2-methoxyestradiol as a mediator of the antiatherosclerotic actions of estradiol. Furthermore, evaluation of the effects of 2-methoxyestradiol on cardiovascular disease endpoints in ongoing clinical trials is of great interest.
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| 7. |
- Sjöberg, Sara, 1979, et al.
(author)
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CD44-deficiency on hematopoietic cells limits T-cell number but does not protect against atherogenesis in LDL receptor-deficient mice
- 2009
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In: Atherosclerosis. - : Elsevier. - 0021-9150 .- 1879-1484. ; 206:2, s. 369-374
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Journal article (peer-reviewed)abstract
- OBJECTIVE: Vascular and inflammatory cells express adhesion molecule CD44. We demonstrated previously that enhanced CD44 localizes in human atherosclerotic lesions. Apolipoprotein E/cd44 double-deficient mice and apolipoprotein E-deficient mice transplanted with CD44-deficient bone marrow (BM) exhibit reduced atherosclerosis. Since CD44 is a novel factor in atherogenesis, it is imperative that it is investigated in more than one animal model to conclusively determine its role in this particular disease pathology. To test the hypothesis that CD44 expressed by hematopoietic cells plays a critical role in atherogenesis in the low density lipoprotein (LDL) receptor-deficient mouse model, we performed BM reconstitution experiments.METHODS: Lethally irradiated LDL receptor-deficient mice were transplanted with either CD44-deficient or wild-type BM. Beginning 10 weeks after successful reconstitution, mice consumed a cholesterol-enriched atherogenic diet for 6 or 11 weeks.RESULTS: Surprisingly, CD44-deficiency on BM-derived inflammatory cells did not affect lesion size. Additionally, neither group displayed differences in smooth muscle cell, macrophage, collagen, or elastin content as well as lipoprotein levels. However, lesions in CD44-deficient BM-recipient mice contained fewer T-cells compared to wild-type BM mice. Interestingly, CD44-deficient T-cells expressed less chemokine receptor-5 mRNA. Furthermore, in vivo leukocyte adhesion decreased in CD44-deficient mice compared to wild-type mice.CONCLUSION: This study surprisingly revealed that atherogenesis does not require CD44 expression on hematopoietic cells in the LDL receptor-deficient mouse model. However, CD44 promotes T-cell recruitment, downregulates chemokine receptor-5, and participates critically in leukocyte adhesion in vivo. Consequently, the anti-atherogenic role of CD44 may require CD44-deficiency on cell types other than inflammatory cells in the LDL receptor-deficient mouse model.
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| 8. |
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| 9. |
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| 10. |
- Synnergren, Jane, 1967, et al.
(author)
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Cardiomyogenic gene expression profiling of differentiating human embryonic stem cells.
- 2008
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In: Journal of biotechnology. - : Elsevier BV. - 0168-1656 .- 1873-4863. ; 134:1-2, s. 162-70
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Journal article (peer-reviewed)abstract
- Human embryonic stem cells (hESCs) can differentiate into a variety of specialized cell types. Thus, they provide a model system for embryonic development to investigate the molecular processes of cell differentiation and lineage commitment. The development of the cardiac lineage is easily detected in mixed cultures by the appearance of spontaneously contracting areas of cells. We performed gene expression profiling of undifferentiated and differentiating hESCs and monitored 468 genes expressed during cardiac development and/or in cardiac tissue. Their transcription during early differentiation of hESCs through embryoid bodies (EBs) was investigated and compared with spontaneously differentiating hESCs maintained on feeders in culture without passaging (high-density (HD) protocol). We observed a larger variation in the gene expression between cells from a single cell line that were differentiated using two different protocols than in cells from different cell lines that were cultured according to the same protocol. Notably, the EB protocol resulted in more reproducible transcription profiles than the HD protocol. The results presented here provide new information about gene regulation during early differentiation of hESCs with emphasis on the cardiomyogenic program. In addition, we also identified regulatory elements that could prove critical for the development of the cardiomyocyte lineage.
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