Publications

227 Publications visible to you, out of a total of 227

Abstract (Expand)

Medulloblastoma is a malignant invasive embryonal tumor, occurring in children mainly. It is rare in adults (\textless1% of adult brain tumors), and so comprehensive cytogenetic and molecular biological data on adult medulloblastomas are very limited. Conventional therapies provide disappointing long-term disease control, and new therapeutic options are being tested. We performed comprehensive cytogenetic analyses of an adult medulloblastoma, WHO grade IV, using trypsin-Giemsa staining (GTG-banding), multicolor fluorescence in situ hybridization (M-FISH), and locus-specific FISH, complemented by molecular karyotyping using high-density single nucleotide polymorphism (SNP) arrays. GTG-banding of 25 metaphases revealed 31 structural chromosomal aberrations, predominantly located on chromosomes 4q, 9q, 10q, 11p, and 20q, which were confirmed by M-FISH. Two novel, so far not described translocations were found: t(4;11)(q25;p15) and t(9;20)(p23;p12). GTG-banding, locus-specific FISH, and M-FISH detected numerical changes of chromosomes 8, 14, 18, 19, 20, 21, and 22. Molecular karyotyping by SNP array confirmed chromosomal changes -2p, -10q, -16q, and -Xq and revealed de novo partial uniparental disomy 1q and 9q. Applying an upcoming therapeutic approach, we found that primary medulloblastoma cells were resistant to TRAIL, a novel anticancer cytokine, but could be efficiently sensitized by cotreatment with the proteasome inhibitor bortezomib. Bortezomib-TRAIL cotreatment may serve as a powerful therapeutic option for medulloblastoma patients.

Authors: Heidrun Holland, Ronald Koschny, Wolfgang Krupp, Jürgen Meixensberger, Manfred Bauer, Ralf Schober, Holger Kirsten, Tom M. Ganten, Peter Ahnert

Date Published: 1st Oct 2007

Publication Type: Journal article

Abstract (Expand)

PURPOSE\backslashr\backslashnMalignant gliomas are the most aggressive human brain tumors without any curative treatment. The antitumor effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in gliomas has thus far only been thoroughly established in tumor cell lines. In the present study, we investigated the therapeutic potential of TRAIL in primary human glioma cells.\backslashr\backslashnEXPERIMENTAL DESIGN\backslashr\backslashnWe isolated primary tumor cells from 13 astrocytoma and oligoastrocytoma patients of all four WHO grades of malignancy and compared the levels of TRAIL-induced apoptosis induction, long-term tumor cell survival, caspase, and caspase target cleavage.\backslashr\backslashnRESULTS\backslashr\backslashnWe established a stable culture model for isolated primary human glioma cells. In contrast to cell lines, isolated primary tumor cells from all investigated glioma patients were highly TRAIL resistant. Regardless of the tumor heterogeneity, cotreatment with the proteasome inhibitor bortezomib efficiently sensitized all primary glioma samples for TRAIL-induced apoptosis and tremendously reduced their clonogenic survival. Due to the pleiotropic effect of bortezomib-enhanced TRAIL DISC formation upon TRAIL triggering, down-regulation of cFLIP(L) and activation of the intrinsic apoptosis pathway seem to cooperatively contribute to the antitumor effect of bortezomib/TRAIL cotreatment.\backslashr\backslashnCONCLUSION\backslashr\backslashnTRAIL sensitivity of tumor cell lines is not a reliable predictor for the behavior of primary tumor cells. The widespread TRAIL resistance in primary glioma cells described here questions the therapeutic clinical benefit of TRAIL as a monotherapeutic agent. Overcoming TRAIL resistance by bortezomib cotreatment might, however, provide a powerful therapeutic option for glioma patients.

Authors: Ronald Koschny, Heidrun Holland, Jaromir Sykora, Tobias L. Haas, Martin R. Sprick, Tom M. Ganten, Wolfgang Krupp, Manfred Bauer, Peter Ahnert, Jürgen Meixensberger, Henning Walczak

Date Published: 1st Jun 2007

Publication Type: Journal article

Abstract (Expand)

DNA genotyping is important for epidemiological and clinical studies and diagnosis for individuals. Genotyping error can strongly influence the outcome of such investigations. One possible reason for genotyping error is additional DNA sequence variation, which can lead to allelic dropout. Based on a published study where allelic dropout occurred in genotyping the cholesteryl ester transfer protein TaqIB polymorphism by a TaqMan-based method, we investigated the susceptibility of the single-base extension (SBE)-based GenoSNIP method to additional sequence variation at the primer attachment site. SBE genotyping was applied to 147 patient samples with known alleles and to synthetic SBE templates. Variables were positions of nucleotide mismatches, yield of SBE reactions, primer design, and ratio of alleles in the template. No allelic dropout occurred when genotyping the TaqIB polymorphism regardless of the reported nucleotide mismatch. Yields of SBE assays critical for allelic dropout were decreased in the presence of the reported nucleotide mismatch depending on SBE assay design. In a systematic mutation scan, only the position immediately adjacent to the polymorphism caused allelic dropout under standard conditions. Depending on SBE assay design, changes in allelic ratio due to a nucleotide mismatch were similar in appearance to changes due to sample mixture or copy number variation. In conclusion, we found the SBE genotyping assays to be relatively robust against interfering DNA variations. The importance of appropriate design and validation of assays, especially in regard to critical yields and potentially interfering nucleotide mismatches, should be emphasized particularly in clinical settings. Care should be taken when interpreting observed changes in the allelic ratio, which could be caused by nucleotide mismatches, sample mixtures, or copy number variation.

Authors: Holger Kirsten, Daniel Teupser, Jana Weissfuss, Grit Wolfram, Frank Emmrich, Peter Ahnert

Date Published: 20th Mar 2007

Publication Type: Journal article

Abstract (Expand)

Esthesioneuroblastoma is a malignant neuroectodermal tumor originating from olfactory epithelial cells in the nasal vault. Due to the rarity of this tumor entity, cytogenetic data are very limited. Therefore, we performed comprehensive cytogenetic analyses of an esthesioneuroblastoma, Hyam’s grade III-IV, using trypsin-Giemsa staining (GTG banding), multicolor fluorescence in situ hybridization (M-FISH), and locus-specific FISH complemented by molecular karyotyping using high-density single nucleotide polymorphism arrays. GTG banding of 25 metaphases revealed 54 structural intrachromosomal aberrations, predominantly located on 2q, 6q, 21q, and 22q, which were confirmed by FISH analysis. Interestingly, we found two novel, so far not described deletions, del(2)(q37) and del(21)(q22). Using GTG banding, locus-specific FISH, and M-FISH, we detected numeric changes of chromosomes 5, 17, 19, and 22, as well as trisomy 8 at low frequency. Applying SNP array karyotyping, we confirmed the chromosomal aberrations del(2)(q37.3), del(3)(q27.2), del(10)(q26.11), chromosomal imbalance on 17q, del(21)(q22), and revealed a number of so far unknown aberrations (gain of 2q14.3, 13q33.3, and 13q34). While the cytogenetically revealed low frequency mosaic del(6)(q22q24) was not visible using SNP array karyotyping, some of the smaller imbalances (SNP array data) could not have been detected by classic cytogenetic analysis. Therefore, our study supports the usefulness of applying complementary methods for cytogenetic analysis.

Authors: Heidrun Holland, Ronald Koschny, Wolfgang Krupp, Jürgen Meixensberger, Manfred Bauer, Holger Kirsten, Peter Ahnert

Date Published: 1st Mar 2007

Publication Type: Journal article

Abstract

Not specified

Authors: Anke Tönjes, Markus Scholz, Mathias Fasshauer, Jürgen Kratzsch, Fauci Rassoul, Michael Stumvoll, Matthias Blüher

Date Published: 27th Feb 2007

Publication Type: Journal article

Abstract (Expand)

Motivated by linkage data and the hypothesis that angiogenesis plays a functional role in rheumatoid arthritis (RA), Jacq and colleagues present a family-based, multi-stage, candidate gene association study in French and European Caucasians in a paper on the association of the ITGAV rs3738919-C variant allele with RA (C-containing genotypes: odds ratio 1.94, confidence interval 1.3 to 2.9, P = 0.002). Support comes from a recent genome-wide study, which on its own would have missed identifying the association. Further research into the associating variant will require detailed haplotype analysis, verification in further studies, and research involving intermediate phenotypes or direct functional experiments. This new RA risk factor supports the role of angiogenesis in the disease. Motivated by linkage data and the hypothesis that angiogenesis plays a functional role in rheumatoid arthritis (RA), Jacq and colleagues present a family-based, multi-stage, candidate gene association study in French and European Caucasians in a paper on the association of the ITGAV rs3738919-C variant allele with RA (C-containing genotypes: odds ratio 1.94, confidence interval 1.3 to 2.9, P = 0.002). Support comes from a recent genome-wide study, which on its own would have missed identifying the association. Further research into the associating variant will require detailed haplotype analysis, verification in further studies, and research involving intermediate phenotypes or direct functional experiments. This new RA risk factor supports the role of angiogenesis in the disease. Motivated by linkage data and the hypothesis that angiogenesis plays a functional role in rheumatoid arthritis (RA), Jacq and colleagues present a family-based, multi-stage, candidate gene association study in French and European Caucasians in a paper on the association of the ITGAV rs3738919-C variant allele with RA (C-containing genotypes: odds ratio 1.94, confidence interval 1.3 to 2.9, P = 0.002). Support comes from a recent genome-wide study, which on its own would have missed identifying the association. Further research into the associating variant will require detailed haplotype analysis, verification in further studies, and research involving intermediate phenotypes or direct functional experiments. This new RA risk factor supports the role of angiogenesis in the disease.

Authors: Peter Ahnert, Holger Kirsten

Date Published: 2007

Publication Type: Journal article

Abstract

Not specified

Authors: Sandra Mahr, Holger Kirsten, Brigitte Mueller

Date Published: 2007

Publication Type: Journal article

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