Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA120307 | ENA |
REPOSITORIES: ENA
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Project description:Soft tissue sarcomas are a diverse set of fatal human tumors where few agents have demonstrable clinical efficacy, with the standard therapeutic combination of doxorubicin and ifosfamide showing only a 25-30% response rate in large multi-institutional trials. Although liposarcomas are the most common histological form of adult soft tissue sarcomas, research in this area is severely hampered by the lack of experimentally tractable in vitro model systems. To this end, here we describe a novel in vitro model for human pleomorphic liposarcoma. The cell line (LS2) is derived from a pleomorphic liposarcoma that utilizes Alternative Lengthening of Telomeres (ALT) mechanism of telomere maintenance, which may be particularly important in modulating the response of this tumor type to DNA damaging agents. We present detailed baseline molecular and genomic data, including genome wide copy number and transcriptome profiles, for this model compared to its parental tumor and a panel of liposarcomas covering multiple histologies. The model has retained essentially all of the detectable alterations in copy number that are seen in the parental tumor, and shows molecular karyotypic and expression profiles consistent with pleomorphic liposarcomas. We also demonstrate the utility of this model, together with two additional human liposarcoma cell lines, to investigate the relationship between topoisomerase 2A expression and the sensitivity of ALT-positive liposarcomas to doxorubicin. This model, together with its associated baseline data, provide a powerful new tool to develop treatments for this clinically poorly-tractable tumor, and to investigate the contribution that ALT makes to modulating sensitivity to DNA damaging chemotherapeutic agents such as doxorubicin. Affymetrix U133 2.0 expression analyses were performed for 30 liposarcoma tumors, including 2 recurrences of 2 tumors. In addition, analyses were performed for three replicates of a tumor-derived cell line, LS2, as well as the tumor from which it was derived (5228). Finally, the Affymetrix Human Genome 50K DNA Mapping Array was used to determine copy number profiles for two Passages of LS2, as well as tumor 5228.
2010-03-03 | E-GEOD-19449 | biostudies-arrayexpress
Project description:Soft tissue sarcomas are a diverse set of fatal human tumors where few agents have demonstrable clinical efficacy, with the standard therapeutic combination of doxorubicin and ifosfamide showing only a 25-30% response rate in large multi-institutional trials. Although liposarcomas are the most common histological form of adult soft tissue sarcomas, research in this area is severely hampered by the lack of experimentally tractable in vitro model systems. To this end, here we describe a novel in vitro model for human pleomorphic liposarcoma. The cell line (LS2) is derived from a pleomorphic liposarcoma that utilizes Alternative Lengthening of Telomeres (ALT) mechanism of telomere maintenance, which may be particularly important in modulating the response of this tumor type to DNA damaging agents. We present detailed baseline molecular and genomic data, including genome wide copy number and transcriptome profiles, for this model compared to its parental tumor and a panel of liposarcomas covering multiple histologies. The model has retained essentially all of the detectable alterations in copy number that are seen in the parental tumor, and shows molecular karyotypic and expression profiles consistent with pleomorphic liposarcomas. We also demonstrate the utility of this model, together with two additional human liposarcoma cell lines, to investigate the relationship between topoisomerase 2A expression and the sensitivity of ALT-positive liposarcomas to doxorubicin. This model, together with its associated baseline data, provide a powerful new tool to develop treatments for this clinically poorly-tractable tumor, and to investigate the contribution that ALT makes to modulating sensitivity to DNA damaging chemotherapeutic agents such as doxorubicin.
2010-03-03 | GSE19449 | GEO
Project description:Doxorubicin is considered one of the most potent established chemotherapeutics in the treatment of liposarcoma; however, the response rates usually below 30%, are still disappointing. This study was performed to identify gene expression changes in liposarcoma after doxorubicin treatment. Cells of 19 primary human liposarcoma were harvested intraoperatively and brought into cell culture. Cells were incubated with doxorubicin for 24 h, RNA was isolated and differential gene expression was analysed by the microarray technique. We used microarrays to detail the global gene expression changes following doxorubicin treatment of primary liposarcoma cell cultures Experiment Overall Design: We compared untreated primary cell cultures obtained from liposarcoma treated with doxorubicin treated cultures to determine global gene expression changes by microarray analysis
2008-10-26 | E-GEOD-12972 | biostudies-arrayexpress
Project description:Doxorubicin is considered one of the most potent established chemotherapeutics in the treatment of liposarcoma; however, the response rates usually below 30%, are still disappointing. This study was performed to identify gene expression changes in liposarcoma after doxorubicin treatment. Cells of 19 primary human liposarcoma were harvested intraoperatively and brought into cell culture. Cells were incubated with doxorubicin for 24 h, RNA was isolated and differential gene expression was analysed by the microarray technique. We used microarrays to detail the global gene expression changes following doxorubicin treatment of primary liposarcoma cell cultures Keywords: response to chemotherapeutic agent
2008-10-06 | GSE12972 | GEO
Project description:Soft tissue sarcomas are aggressive mesenchymal cancers that affect more than 10,600 new patients per year in the US, about 40% of whom will die of their disease. Soft tissue sarcomas exhibit remarkable histologic diversity, with more than 50 recognized subtypes, but our knowledge of their genomic alterations is limited. Here we describe the results of an integrative analysis of DNA sequence, copy number, and mRNA expression in 207 samples encompassing seven major subtypes. Genes mutated in more than 5% of samples within a subtype were KIT (in gastrointestinal stromal cell tumors, or GISTs), TP53 (pleomorphic liposarcomas), PIK3CA (myxoid/round-cell liposarcoma), and NF1 (both myxofibrosarcoma and pleomorphic liposarcoma). We show evidence that PIK3CA mutations, found in 18% of myxoid/round-cell liposarcomas, activate AKT in vivo and are associated with poor outcomes. Point mutations in the tumor suppressor gene NF1 were discovered in both myxofibrosarcomas and pleomorphic liposarcomas, while genomic deletions were observed in all subtypes at varying frequencies. Finally, we found that short hairpin RNA-based knockdown of a subset of genes that are amplified in dedifferentiated liposarcoma, including CDK4 and YEATS4, decreased cell proliferation. Our study yields the most detailed map of molecular alterations across diverse sarcoma subtypes to date and provides potential subtype-specific targets for therapy. Human soft-tissue sarcoma specimens were profiled on Affymetrix U133A arrays per manufacturer's instructions.
2010-07-05 | E-GEOD-21122 | biostudies-arrayexpress
Project description:Soft tissue sarcomas are aggressive mesenchymal cancers that affect more than 10,600 new patients per year in the US, about 40% of whom will die of their disease. Soft tissue sarcomas exhibit remarkable histologic diversity, with more than 50 recognized subtypes, but our knowledge of their genomic alterations is limited. Here we describe the results of an integrative analysis of DNA sequence, copy number, and mRNA expression in 207 samples encompassing seven major subtypes. Genes mutated in more than 5% of samples within a subtype were KIT (in gastrointestinal stromal cell tumors, or GISTs), TP53 (pleomorphic liposarcomas), PIK3CA (myxoid/round-cell liposarcoma), and NF1 (both myxofibrosarcoma and pleomorphic liposarcoma). We show evidence that PIK3CA mutations, found in 18% of myxoid/round-cell liposarcomas, activate AKT in vivo and are associated with poor outcomes. Point mutations in the tumor suppressor gene NF1 were discovered in both myxofibrosarcomas and pleomorphic liposarcomas, while genomic deletions were observed in all subtypes at varying frequencies. Finally, we found that short hairpin RNA-based knockdown of a subset of genes that are amplified in dedifferentiated liposarcoma, including CDK4 and YEATS4, decreased cell proliferation. Our study yields the most detailed map of molecular alterations across diverse sarcoma subtypes to date and provides potential subtype-specific targets for therapy. Human soft tissue sarcoma samples and their matched normal DNA were profiled on Affymetrix 250K SNP (Sty) arrays per manufacturer's instructions
2010-07-05 | E-GEOD-21123 | biostudies-arrayexpress
Project description:Despite an improved survival of myxoid liposarcoma (MLS) patients, existing therapies have shortcomings including therapy resistance. To study the characteristics of therapy resistance in MLS, we treated three MLS cell lines with the commonly used chemotherapy drug doxorubicin and compared their gene expression profiles with untreated control cells.
2018-02-23 | GSE110997 | GEO
Project description:Telomere attrition ultimately leads to the activation of protective cellular responses such as apoptosis or senescence. Impairment of such mechanisms can allow continued proliferation despite the presence of dysfunctional telomeres. Under such conditions, high levels of genome instability are often engendered. Data from both mouse and human model systems indicate that a period of genome instability might facilitate tumorigenesis. Here, we employ a liposarcoma model system to assay telomere maintenance mechanism-specific genetic alterations. A multiassay approach was used to assess the telomere maintenance mechanism(s) active in tumors. Genomic DNA from these samples was then analyzed by high resolution DNA mapping array in order to identify genetic alterations. Our data reveal a higher level of genome instability in ALT-positive tumors as compared with telomerase-positive tumors, whereas tumors lacking both mechanisms have relatively low levels of genome instability. The bulk of the genetic changes are amplifications, regardless of the mode of telomere maintenance employed. We also identified genetic changes specific to the ALT mechanism, e.g., deletion of chromosome 1q32.2-q44, as well as changes that are underrepresented amongst ALT-positive tumors, such as amplification of chromosome 12q14.3-q21.2. Taken together, these studies provide insight into the molecular pathways involved in the regulation of ALT and reveal several loci that might be exploited either as prognostic markers or targets of chemotherapeutic intervention. Experiment Overall Design: Goal: To study telomere maintenance and genetic alterations in liposarcoma using Affymetrix Mapping 50K Xba 240 GeneChip. Experiment Overall Design: Brief description: Telomere attrition ultimately leads to the activation of protective cellular responses such as apoptosis or senescence. Impairment of such mechanisms, however, can allow continued proliferation despite the presence of dysfunctional telomeres. Under such conditions, high levels of genome instability are often engendered. Data from both mouse and human model systems indicate that a period of genome instability might facilitate tumorigenesis. The high-density SNP-based microarrays (e.g., Affymetrix 100K arrays) can detect deletions, amplifications, and loss-of-heterozygosity on a genome in the liposarcoma samples. Chromosomal alterations of liposarcoma should provide insight into the molecular pathways involved in the regulation of ALT and reveal several loci that might be exploited either as prognostic markers or targets of chemotherapeutic intervention. Experiment Overall Design: Quality control steps taken: Experiment Overall Design: a. PCR-based quality assessment of liposarcoma tissue genomic DNA Experiment Overall Design: b. Nanodrop analysis of preprocessed DNA prior to array hybridization Experiment Overall Design: c. Analysis of array call rates following hybridization (array experiments giving call rates of less than 80% were routinely repeated) Experiment Overall Design: Data extraction and processing protocols Experiment Overall Design: a. Image scanning hardware and software, and processing procedures and parameters: SNP array hybridization was detected using a GCS3000 scanner (Affymetrix). SNP calls and signal quantification were obtained with Gene Chip Operating System (GCOS) 1.2 and Affymetrix GDAS 3.0 with Dynamic Model Mapping Analysis by default settings (0.25) for both homozygote and heterozygote call thresholds. Copy number analyses were carried out using Affymetrix Chromosome Copy Number Analysis Tool (CNAT) 2.1 with a default genomic smoothing window setting of 0.5 Mb. Experiment Overall Design: b. Normalization, transformation and data selection procedures and parameters. Array data was normalized by a reference data set with CNAT. Experiment Overall Design: c. Definition of chromosomal aberration, amplification, deletion and LOH used for data interpretation: These definitions and their algorithms were described in detail by Huang, et al: Whole genome DNA copy number changes identified by high density oligonucleotide arrays. Hum Genomics. 2004 May;1(4):287-99.
2008-06-16 | E-GEOD-8046 | biostudies-arrayexpress
Project description:Telomere attrition ultimately leads to the activation of protective cellular responses such as apoptosis or senescence. Impairment of such mechanisms can allow continued proliferation despite the presence of dysfunctional telomeres. Under such conditions, high levels of genome instability are often engendered. Data from both mouse and human model systems indicate that a period of genome instability might facilitate tumorigenesis. Here, we employ a liposarcoma model system to assay telomere maintenance mechanism-specific genetic alterations. A multiassay approach was used to assess the telomere maintenance mechanism(s) active in tumors. Genomic DNA from these samples was then analyzed by high resolution DNA mapping array in order to identify genetic alterations. Our data reveal a higher level of genome instability in ALT-positive tumors as compared with telomerase-positive tumors, whereas tumors lacking both mechanisms have relatively low levels of genome instability. The bulk of the genetic changes are amplifications, regardless of the mode of telomere maintenance employed. We also identified genetic changes specific to the ALT mechanism, e.g., deletion of chromosome 1q32.2-q44, as well as changes that are underrepresented amongst ALT-positive tumors, such as amplification of chromosome 12q14.3-q21.2. Taken together, these studies provide insight into the molecular pathways involved in the regulation of ALT and reveal several loci that might be exploited either as prognostic markers or targets of chemotherapeutic intervention. Keywords: genotype, genome instability, copy number alteration, liposarcoma, ALT, telomerase, telomere
2008-05-01 | GSE8046 | GEO
Project description:A gene expression signature classifying telomerase and ALT immortalisation reveals an hTERT regulatory network and suggests a mesenchymal stem cell origin for ALT Telomere length is maintained by 2 known mechanisms, activation of telomerase or alternative lengthening of telomeres (ALT). The molecular mechanisms regulating the ALT phenotype are poorly understood and it is unknown how the decision of which pathway to activate is made at the cellular level. We have shown previously that active repression of telomerase gene expression by chromatin remodelling of the promoters is one mechanism of regulation, however other genes and signalling networks are likely to be required to regulate telomerase and maintain the ALT phenotype. Using gene expression profiling we have uncovered a signature of 1305 genes to distinguish telomerase positive and ALT cell lines. By combining this with gene expression profiles of liposarcoma tissue samples we refined this signature to 297 genes significantly associated with telomere maintenance mechanism. Network analysis of known direct interactions between genes within this signature revealed a regulatory signalling network consistent with a model of hTERT repression in ALT cell lines and liposarcomas. This network expands on our existing knowledge of hTERT regulation and provides a platform to understand differential regulation of hTERT in different tumour types and normal tissues. In addition we show evidence to suggest a novel mesenchymal stem cell origin for ALT immortalisation in cell lines and mesenchymal tissues. Keywords: cell type comparison, gene expression
2009-11-02 | GSE14487 | GEO