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- Hamaguchi, I, et al.
(författare)
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Lentivirus vector gene expression during ES cell-derived hematopoietic development in vitro
- 2000
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Ingår i: Journal of Virology. - : American Society for Microbiology. - 0022-538X .- 1098-5514. ; 74:22, s. 84-10778
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Tidskriftsartikel (refereegranskat)abstract
- The murine embryonal stem (ES) cell virus (MESV) can express transgenes from the long terminal repeat (LTR) promoter/enhancer in undifferentiated ES cells, but expression is turned off upon differentiation to embryoid bodies (EBs) and hematopoietic cells in vitro. We examined whether a human immunodeficiency virus type 1-based lentivirus vector pseudotyped with the vesicular stomatitis virus G protein (VSV-G) could transduce ES cells efficiently and express the green fluorescent protein (GFP) transgene from an internal phosphoglycerate kinase (PGK) promoter throughout development to hematopoietic cells in vitro. An oncoretrovirus vector containing the MESV LTR and the GFP gene was used for comparison. Fluorescence-activated cell sorting analysis of transduced CCE ES cells showed 99.8 and 86.7% GPF-expressing ES cells in the VSV-G-pseudotyped lentivirus (multiplicity of infection [MOI] = 59)- and oncoretrovirus (MOI = 590)-transduced cells, respectively. Therefore, VSV-G pseudotyping of lentiviral and oncoretrovirus vectors leads to efficient transduction of ES cells. Lentivirus vector integration was verified in the ES cell colonies by Southern blot analysis. When the transduced ES cells were differentiated in vitro, expression from the oncoretrovirus LTR was severely reduced or extinct in day 6 EBs and ES cell-derived hematopoietic colonies. In contrast, many lentivirus-transduced colonies, expressing the GFP gene in the undifferentiated state, continued to express the transgene throughout in vitro development to EBs at day 6, and many continued to express in cells derived from hematopoietic colonies. This experimental system can be used to analyze lentivirus vector design for optimal expression in hematopoietic cells and for gain-of-function experiments during ES cell development in vitro.
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- Panagopoulos, I, et al.
(författare)
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Clinical impact of molecular and cytogenetic findings in synovial sarcoma
- 2001
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Ingår i: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257. ; 31:4, s. 72-362
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Tidskriftsartikel (refereegranskat)abstract
- Synovial sarcoma is an aggressive soft-tissue tumor that accounts for up to 10% of soft-tissue sarcomas. Cytogenetically, synovial sarcoma is characterized by the t(X;18)(p11;q11), found in more than 95% of the tumors. This translocation results in rearrangements of the SYT gene in 18q11 and one of the SSX1, SSX2, or SSX4 genes in Xp11, creating a SYT/SSX1, SYT/SSX2, or SYT/SSX4 chimeric gene. It has been shown that patients with SYT/SSX1 fusion genes have a shorter metastasis-free survival than do patients with SYT/SSX2. Previous studies have also suggested that clonal evolution may be associated with disease progression. In the present study, RT-PCR analysis showed that all 64 examined synovial sarcomas from 54 patients had SYT-SSX chimeric genes. SYT/SSX1 was found in 40 tumors from 33 patients, SYT/SSX2 in 23 tumors from 20 patients, and SYT/SSX4 in one case. Two patients had variant SYT/SSX2 transcripts, with 57 bp and 141 bp inserts, respectively, between the known SYT and SSX2 sequences. Patients with tumors with SYT/SSX1 fusions had a higher risk of developing metastases compared to those with SYT/SSX2 fusions (P = 0.01). The reciprocal transcripts SSX1/SYT and SSX2/SYT were detected using nested PCR in 11 of the 40 samples with SYT/SSX1 and 5 of the 23 samples with SYT/SSX2, respectively. Among 20 blood samples, SYT/SSX1 and SYT/SSX2 were detected in one sample each. The t(X;18), or variants thereof, was found cytogenetically in all patients but three. Among 32 primary tumors, the t(X;18) or a variant translocation was the sole anomaly in 10. In contrast, of the seven metastatic lesions that were investigated prior to radiotherapy, only one had a t(X;18) as the sole anomaly; all other tumors displayed complex karyotypes. Cytogenetic complexity in primary tumors was, however, not associated with the development of metastases. Tumors with SYT/SSX2 less often (4/12 vs. 7/15) showed complex karyotypes than did tumors with SYT/SSX1, but the difference was not significant. Combining cytogenetic complexity and transcript data, we found that the subgroup of patients with tumors showing simple karyotypes and SYT/SSX2 fusion had the best clinical outcome (2/8 patients developed metastases), and those with tumors showing complex karyotypes together with SYT/SSX1 fusion the worst (6/7 patients developed metastases). This corresponded to 5-year metastasis-free survival rates of 0.58 and 0.0, respectively (P = 0.02).
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- Crnalic, S, et al.
(författare)
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Establishment and characterisation of a human clear cell sarcoma model in nude mice
- 2002
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136. ; 101:6, s. 505-511
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Tidskriftsartikel (refereegranskat)abstract
- We have established a new experimental model of human clear cell sarcoma, UM-CCSI, using serial subcutaneous transplantation of intact tumour tissue in nude mice. The heterotransplanted nude mouse tumours retained characteristic morphological features of the primary clear cell sarcoma. Immunohistochemical analysis showed the retained expression patterns of S-100 protein, melanoma-associated antigen HMB-45 and vimentin in the xenografts as compared to the primary tumour. DNA index showed low variations both between the xenografts in the same passage and between the serial passages. Cytogenetic analysis of the primary tumour and the xenografts showed the unbalanced translocation der(6)t(6; I 2)(p23;q13). Based on the combined genetic data a reasonable interpretation of our findings is that there was a complex chromosomal rearrangement resulting in a cytogenetically cryptic EWS-ATFI fusion gene. Analysis of cell kinetics using in vivo incorporation of iododeoxyuridine and flow cytometry showed generally short potential doubling time (T-pot) of the xenografts. Volume doubling time showed low variations without correlation with T-pot. The retained phenotypic and genotypic characteristics of the primary tumour and the morphological and structural stability over time makes the model suitable for studies on the tumour biology and treatment of clear cell sarcoma. (C) 2002 Wiley-Liss, Inc.
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- Koukourakis, Michael I., et al.
(författare)
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C2028T polymorphism in exon 12 and dinucleotide repeat polymorphism in intron 13 of the HIF-1 alpha gene define HIF-1 alpha protein expression in non-small cell lung cancer
- 2006
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Ingår i: Lung Cancer. - : Elsevier BV. - 1872-8332 .- 0169-5002. ; 53:3, s. 257-262
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: In this study, we investigated whether polymorphisms of the HIF-1 alpha gene may account for the patterns of HIF-1 alpha protein expression in non-small cell lung carcinomas (NSCLC) and the expression of HIF-1 alpha down-stream proteins. Methods: Specific HIF-1 alpha polymorphisms were assessed in a series of patients with NSCLC: (a) the C to T transition at nucleotide 1744 (position 2028 according to sequence with accession number NM_001530, which gives rise to Pro/Ser variation at codon 582), (b) the G to A nucleotide substitution at point 1790 (position 2046 according to sequence with accession number NM_001530, which gives rise to Ala/Thr variation at codon 588), and (c) the dinucleotide GT repeat polymorphism in intron 13. Immunohistochemistry for HIF-1 alpha and down-stream proteins (VEGF, LDH-5, GLUT-1) was also performed in tumor material. Results: A strong association of the P582S polymorphism and of GT repeat polymorphism higher than 14/14 with increased HIF-1 alpha expression was noted. HIF-1 alpha polymorphism did not relate to the expression of the HIF-1 alpha downstream proteins analysed, but significant association of HIF-1 alpha expression with LDH-5 was confirmed (p=0.008). Conclusions: HIF-1 alpha polymorphisms may have an important impact on HIF-protein stability and, eventually, function. (C) 2006 Elsevier Ireland Ltd. All rights reserved.
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- Nilsson, Martin, et al.
(författare)
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Fusion of the HMGA2 and NFIB genes in lipoma
- 2005
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Ingår i: Virchows Archiv: an international journal of pathology. - : Springer Science and Business Media LLC. - 1432-2307. ; 447:5, s. 855-858
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Tidskriftsartikel (refereegranskat)abstract
- The major cytogenetic subgroup of lipomas is characterized by aberrations of chromosome segment 12q13-15, which recombines with a large number of other chromosomal regions. The gene HMGA2 is the main target in these aberrations. For some recurrent rearrangements, chimeric transcripts, including the 5' part of HMGA2, have been described. The 3' partners identified are LPP, LHFP, CMKOR1, and EBF. In addition, subsets of other benign solid tumors show aberrations of 12q13-15. Among pleomorphic adenomas of the salivary glands, where the preferred recombination partner with 12q13-15 is 9p22-24, an HMGA2/NFIB fusion gene has been reported. In the present study, two cases of lipoma with rearrangements of 9p22-24 and 12q15 were analyzed by reverse transcription polymerase chain reaction to find out if HMGA2/NFIB was also present in lipoma. An in-frame fusion transcript, combining the four first exons of HMGA2 with exon 8 of NFIB, was detected in one case. It was identical to a transcript that was previously described in salivary gland adenoma and contained a stop codon shortly 3' of the fusion point. The finding of the same fusion gene in different tumors is not unique. For example, HMGA2/LPP has been reported in lipoma, pulmonary chondroid hamartoma, and soft tissue chondroma. Since similar 9;12 translocations have been described also in rare cases of hamartoma and uterine leiomyoma, the occurrence of HMGA2/NFIB could be postulated in these tumors as well.
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| 8. |
- Viskadourakis, Z., et al.
(författare)
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Low-temperature ferroelectric phase and magnetoelectric coupling in underdoped La2CuO4+x
- 2012
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 85:21
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Tidskriftsartikel (refereegranskat)abstract
- We report the discovery of ferroelectricity below 4.5 K in highly underdoped La2CuO4+x accompanied by slow charge dynamics which develop below T similar to 40 K. An anisotropic magnetoelectric response has also been observed, indicating considerable spin-charge coupling in this lightly doped parent high-temperature copper-oxide superconductor. The ferroelectric state is proposed to develop from polar nanoregions, in which spatial inversion symmetry is locally broken due to nonstoichiometric carrier doping.
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