Project description:Genomic instability is a hallmark of many cancers. Aberrant proliferation in cancer cells leads to the accumulation of alterations in genes that belong to the homologous recombination (HR) DNA double-strand break (DSB) repair pathway. Deficiency in HR-mediated repair (HRR) exacerbates genomic instability and correlates with poor prognosis and development of metastases. Determining HRR deficiency (HRD) in a given tumour is of major clinical relevance as it is associated with therapeutic vulnerabilities. HRD has been widely investigated in certain tumor types such as ovarian and breast cancer but remains greatly unexplored in sarcoma, a rare and heterogeneous group of mesenchymal cancer. Here, we show that specific sarcoma entities are characterized by high levels of genomic instability signatures and a wide range of molecular alterations in HRR genes, while exhibiting a complex pattern of chromosomal instability features. Furthermore, sarcomas carrying HRDness traits exhibit a distinct SARC-HRD transcriptional signatures that predicts PARP inhibitor sensitivity in patient-derived ex vivo sarcoma models. Concomitantly, HRDhigh sarcoma cell models lack RAD51 nuclear foci formation upon DNA damage, further evidencing defects in HR-mediated DNA repair. We further identify the WEE1 kinase as a therapeutic vulnerability for sarcomas with HRDness traits and demonstrate clinical benefit of combining DNA damaging agents and inhibitors of DNA repair pathways in patient-derived ex vivo cell models and in a leiomyosarcoma patient. In summary, we provide the most comprehensive analysis of HRDness in sarcoma to date and support a bench-to-bedside personalized oncological approach to successfully treat sarcoma patients.
Project description:Defects in homologous recombination repair (HRR) in tumours correlate with poor prognosis and metastases development. Determining HRR deficiency (HRD) is of major clinical relevance as it is associated with therapeutic vulnerabilities and remains poorly investigated in sarcoma. Here, we show that specific sarcoma entities exhibit high levels of genomic instability signatures and molecular alterations in HRR genes, while harbouring a complex pattern of chromosomal instability. Furthermore, sarcomas carrying HRDness traits exhibit a distinct SARC-HRD transcriptional signature that predicts PARP inhibitor sensitivity in patient-derived sarcoma cells. Concomitantly, HRDhigh sarcoma cells lack RAD51 nuclear foci formation upon DNA damage, further evidencing defects in HRR. We further identify the WEE1 kinase as a therapeutic vulnerability for sarcomas with HRDness and demonstrate the clinical benefit of combining DNA damaging agents and inhibitors of DNA repair pathways ex vivo and in the clinic. In summary, we provide a personalized oncological approach to treat sarcoma patients successfully.
Project description:Alveolar soft-part sarcoma (ASPS) is an extremely rare, highly vascular soft tissue sarcoma affecting predominantly adolescents and young adults. In an attempt to gain insight into the pathobiology of this enigmatic tumor, we performed the first genome-wide gene expression profiling study. Experiment Overall Design: For seven patients with confirmed primary or metastatic ASPS, RNA samples were isolated immediately following surgery, reverse transcribed to cDNA and each sample hybridized to duplicate high-density human U133 plus 2.0 microarrays. Array data was then analyzed relative to arrays hybridized to universal RNA to generate an unbiased transcriptome. Subsequent gene ontology analysis was used to identify transcripts with therapeutic or diagnostic potential. A subset of the most interesting genes was then validated using quantitative RT-PCR and immunohistochemistry.
Project description:Alveolar soft-part sarcoma (ASPS) is an extremely rare, highly vascular soft tissue sarcoma affecting predominantly adolescents and young adults. In an attempt to gain insight into the pathobiology of this enigmatic tumor, we performed the first genome-wide gene expression profiling study.
Project description:The heterogeneity and multiple histological categories of soft tissue sarcoma (STS) underlie a need for better classification schemes to improve their management. As none are currently available, we aimed to derive hypoxia and intrinsic molecular subtype mRNA abundance signatures for localized soft tissue sarcoma. RNA sequencing was used to identify genes induced by hypoxia in seven STS cell lines.
Project description:NG2/CSPG4 is expressed in soft tissue sarcomas, however, its function in this tumor type, and its capacity to serve as a therapeutic target are unknown. Here, we used genetically engineered mice and cells from human tumors to determine the function of Ng2/Cspg4 in soft tissue sarcoma initiation and growth. We also investigated the potential for NG2/CSPG4 mAb immunotherapy to target human sarcomas established as xenografts in mice. Inhibiting Ng2/Cspg4 expression in established soft tissue sarcomas is associated with a smaller tumor volume and a reduction in cell proliferation. Intriguingly, deleting Ng2/Cspg4 at the time of tumor initiation has the opposite effect. Gene profiling found that Igfbp3/5 are substantially downregulated when Ng2/Cspg4 is depleted at the time of tumor initiation, but upregulated or only minimally downregulated when Ng2/Cspg4 is depleted after tumor initiation. Furthermore, the normal regulation of Igfbp is blunted when Ng2/Cspg4 is deleted at the time of tumor initiation. Our data show a difference in NG2/CSPG4 function in tumor initiation and maintenance, and provides pre-clinical evidence supporting NG2/CSPG4 as a therapeutic approach in soft tissue sarcoma.
Project description:This SuperSeries is composed of the following subset Series: GSE21122: Whole-transcript expression data for soft-tissue sarcoma tumors and control normal fat specimens GSE21123: Affymetrix SNP array data for soft tissue sarcoma samples Refer to individual Series
Project description:RATIONALE: STI571 may interfere with the growth of cancer cells and may be an effective treatment for soft tissue sarcoma.
PURPOSE: Phase I/II trial to study the effectiveness of STI571 in treating patients who have recurrent or refractory soft tissue sarcoma.
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
Project description:RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die.
PURPOSE: Phase II trial to study the effectiveness of ecteinascidin 743 in treating patients who have advanced soft tissue sarcoma.