4836 results for "*oma"

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• Genomic analysis of patient-derived xenograft models reveals intratumor-heterogeneity in endometrial cancer and can predict tumor growth inhibition with talazoparib

  Background: Endometrial cancer (EC) is a major gynecological cancer with increasing incidence. It comprised of four molecular subtypes with differing etiology, prognoses, and response to chemotherapy. In the future, clinical trials testing new single agents or combination therapies will be targeted to the molecular subtype most likely to respond. Pre-clinical models that faithfully represent the molecular subtypes of EC are urgently needed, we sought to develop and characterize a panel of novel EC patient-derived xenograft (PDX) models. Methods: Here, we report whole exome or whole genome sequencing of 11 PDX models and the matched primary tumor. Analysis of multiple PDX lineages and passages was performed to study tumor heterogeneity across lineages and/or passages. Based on recent reports of frequent defects in the homologous recombination (HR) pathway in EC, we assessed mutational signatures and HR deficiency scores and correlated these with in vivo responses to the PARP inhibitor (PARPi) talazoparib in six PDXs representing the copy number high/p53-mutant and mismatch-repair deficient molecular subtypes of EC. Results: PDX models were successfully generated with similar histomorphology from all four molecular subtypes of EC and uterine carcinosarcomas. We also observed a wide range of inter-tumor and intra-tumor heterogeneity across different PDX lineages, however one arm of most PDX models recapitulated the molecular landscape of the primary tumor without major genomic drift. An in vivo response to talazoparib was detected in four copy number high models. Two models (carcinosarcomas) showed a response consistent with stable disease and two models (one copy number high serous EC and another carcinosarcoma) showed significant tumor growth inhibition, albeit one consistent with progressive disease, however all lacked the HR deficiency genomic signature. Conclusions: EC PDX models represent the four molecular subtypes of disease and can capture intra-tumoral heterogeneity of the original primary tumor. PDXs of the copy number high molecular subtype showed sensitivity to PARPi, however, deeper and more durable responses will likely require combination of PARPi with other agents.

  Study EGAS00001004666

• Rna-Seq Leiomyosarcoma subtypes

  Leiomyosarcomas (LMS) are genetically heterogeneous tumors differentiating along smooth muscle lines. Currently, LMS treatment is not informed by molecular subtyping and is associated with highly variable survival. While disease site continues to dictate clinical management, the contribution of genetic factors to LMS subtype, origins, and timing are unknown. Here we analyzed 70 genomes and 130 transcriptomes of LMS, including multiple tumor regions and paired metastases. Molecular profiling highlighted the extremely early origins of LMS. Three specific subtypes of LMS develop from distinct lineages of smooth muscle cells. Of these, dedifferentiated LMS with high immune infiltration and tumors primarily of gynaecological origin acquired the highest burden of genomic mutation and are associated with worse survival. Homologous recombination defects lead to genome-wide mutational signatures, and a corresponding sensitivity to PARP and other DNA damage response inhibitors, suggesting a novel therapeutic strategy for LMS. Finally, by phylogenetic reconstruction, we present evidence that clones seeding lethal metastases arise decades prior to LMS diagnosis.

  Study EGAS00001004783

• Genomic landscape of IG-MYC positive Burkitt lymphoma with precursor B-cell immunophenotype.

  As part of the ICGC, the ICGC MMML-Seq project performed whole genome sequencing of a rare Burkitt lymphoma subtype with precursor B-cell immunophenotype. Analysis were performed in concordance with the guidelines of the ICGC.

  Study EGAS00001002968

• Small molecule inhibitors of LOXL synergize with 5-AZA to restore erythropoiesis in myeloid neoplasms

  Objectives: Bone marrow (BM) stroma and microenvironmental factors in the BM milieu of myeloid neoplasms are increasingly being recognized as novel perspective therapeutic targets. Lysyl oxidases (LOX/LOXL) are crucial enzymes that cross-link collagen and contribute to the deposition of aberrant stiff extracellular matrix (ECM) in the BM of patients with myelodysplastic syndromes (MDS) and myeloproliferative neoplasms (MPN). Here, we studied whether inhibition of LOX/LOXL enzymes produced by BM-derived MSCs favors the differentiation of MDS/MPN hematopoietic stem cell and progenitor cells (HPSCs) and enhances the effects of 5-azacytidine (5-AZA). Methods: Primary co-cultures of MSCs and HPSCs were established from n=31 MDS/MPN patients and treated with the pan-LOX/LOXL inhibitor PXS-5505, 5-AZA or the combination of both for 4 days. At the end of co-culture, HSPC differentiation was assessed by CFU assays and flow cytometry. In some of the experiments, MSCs monolayers were pre-treated or not with PXS-5505 for 6 days and decellularized using 20 mM ammonia. Subsequently, autologous HSPCs were cultured on ECM matrices in the presence of 5-AZA or PXS-5505 + 5-AZA combination with or without inhibitors of integrin signaling such as blebbistatin, Y-27632 and αvβ3-integrin blocking antibodies. Patient-derived xenografts (PDX) were established in NSG mice based on intrafemoral co-injection of HSPCs and autologous MSCs. PDX were treated with 3 cycles of 5-AZA (75 mg/m2), PXS-5505 (30 mg/kg on alternate days for the duration of 5-AZA treatment) or combination of both. Results: MSCs of MDS and MPN patients displayed significant overexpression of LOX/LOXL transcripts as compared to healthy age-matched controls. Remarkably, LOX/LOXL inhibition in MSCs/HSPCs co-cultures increased erythroid differentiation of patient HSPCs that had suboptimal or no response to 5-AZA alone. From a total of n=31 advanced stage MDS/MPN patients, n=11 (35.5%) responded to the combination treatment, which was evidenced by a significant increase of CD235a+CD45- erythroid cell production compared to 5-AZA/PXS/untreated arms (p<0.05). Of note, combination treatment with 5-AZA + PXS-5505 facilitated differentiation of CD235+ erythroid progenitors from HSPCs sub-clones with low mutational VAFs. The presence of MSCs was necessary for the effects of the combination treatment and required direct cell contacts between MSCs and HSPCs. Moreover, PXS-5505-mediated alterations of the ECM composition alone were sufficient to induce erythroid differentiation. Inhibition of integrin-mediated signaling using blebbistatin, Y-27632 and αvβ3-integrin antibodies completely abrogated the effects of PXS-5505 induced erythroid differentiation. In vivo, the combination of PXS-5505 + 5-AZA favored erythroid differentiation of HSPCs and confirmed the in-vitro results. The combination treatment of 5-AZA + PXS-5505 induced the greatest reduction of disease burden as assessed by decrease of spleen indexes, total engraftment rates, BM fibrosis and mutational VAF profiles. Conclusions: The combination of 5-AZA + LOX/LOXL inhibitor PXS-5505 in MDS and MPN synergistically restores erythropoietic differentiation of primary HSPCs. The effect is dependent of contact interaction between HSPCs and niche components, such as MSCs and MSCs-derived ECM. Our data propose a strong rationale for a BM niche targeted combination treatment with 5-AZA + PXS-5505 in transfusion dependent MDS and MPN, which will be assessed in forthcoming clinical trials.

  Study EGAS00001006174

• OpACIN-neo – A Multicenter Phase 2 Study to identify the Optimal neo-Adjuvant Combination scheme of Ipilimumab and Nivolumab – Whole exome sequencing

  The outcome of patients with macroscopic stage III melanoma is poor. Neoadjuvant treatment with ipilimumab plus nivolumab at the standard dosing schedule induced pathological responses in a high proportion of patients in two small independent early-phase trials. However, toxicity of the standard ipilimumab plus nivolumab dosing schedule was high, preventing its broader clinical use. The aim of the OpACIN-neo study (NCT02977052) to identify a dosing schedule of ipilimumab plus nivolumab that is less toxic but equally effective. 86 patients with macroscopic stage III melanoma were randomised to one of three dosing schedules: arm A, two cycles of ipilimumab 3 mg/kg plus nivolumab 1 mg/kg once every 3 weeks; arm B, two cycles of ipilimumab 1 mg/kg plus nivolumab 3 mg/kg once every 3 weeks; or arm C, two cycles of ipilimumab 3 mg/kg once every 3 weeks directly followed by two cycles of nivolumab 3mg/kg once every 2 weeks. Within the first 12 weeks, grade 3–4 immune-related adverse events were observed in 12 (40%) of 30 patients in group A, six (20%) of 30 in group B, and 13 (50%) of 26 in group C. Pathological responses occurred in 24 (80%) patients in group A, 23 (77%) in group B, and 17 (65%) in group C. The 2-year estimated relapse-free survival was 84% for all patients, 97% for patients achieving a pathologic response and 36% for nonresponders (p<0.001). High tumor mutational burden (TMB) and high interferon-gamma-related gene expression signature score (IFN-γ score) were associated with pathologic response and low risk of relapse; pathologic response rate (pRR) was 100% in patients with high IFN-γ score/high TMB, patients with high IFN-γ score/low TMB or low IFN-γ score/high TMB had pRRs of 91% and 88%; while patients with low IFN-γ score/low TMB had a pRR of only 39%. These data demonstrate long-term benefit in patients with a pathologic response and show the predictive potential of TMB and IFN-γ score.

  Study EGAS00001004832

• Dual targeting of polyamine synthesis and uptake in diffuse intrinsic pontine gliomas

  Diffuse intrinsic pontine glioma (DIPG) is an incurable malignant childhood brain tumour, with no active systemic therapies and a 5-year survival of less than 1%. Polyamines are small organic polycations that are essential for DNA replication, translation and cell proliferation. Ornithine decarboxylase 1 (ODC1), the rate limiting enzyme in polyamine synthesis, is irreversibly inhibited by difluoromethylornithine (DFMO). Herein we show that polyamine synthesis is upregulated in DIPG, leading to sensitivity to DFMO. DIPG cells compensate for ODC1 inhibition by upregulation of the polyamine transporter SLC3A2. Treatment with the polyamine transporter inhibitor AMXT 1501 reduced uptake of polyamines in DIPG cells, and co-administration of AMXT 1501 and DFMO led to potent in vitro activity, and significant extension of survival in three aggressive DIPG orthotopic animal models. Collectively, these results demonstrate the potential of dual targeting of polyamine synthesis and uptake as a therapeutic strategy for incurable DIPG.

  Study EGAS00001004905

• ChIP-seq of plasma cell-free nucleosomes identifies gene expression programs of the cells-of-origin

  Cell-free DNA in human plasma provides access to molecular information about the pathological processes in the organs or tumors from which it originates. These DNA fragments are derived from fragmented chromatin in dying cells, and retain some of the cell of origin histone modifications. Here, we apply chromatin immunoprecipitation of cell-free nucleosomes carrying active chromatin modifications followed by sequencing (cfChIP-seq) to 268 human samples. In healthy donors, we identified bone marrow megakaryocytes, but not erythroblasts, as major contributors to the cfDNA pool. In patients with a range of liver diseases, we show that we can identify pathology-related changes in hepatocyte transcriptional programs. In metastatic colorectal carcinoma patients, we detected clinically relevant, and patient-specific information, including transcriptionally active HER2 amplifications. Altogether, cfChIP-seq using low sequencing depth, provides systemic and genome-wide information, can inform diagnosis, and facilitate interrogation of physiological and pathological processes using blood samples.

  Study EGAS00001004913

• Phylogenetic evolution of metastatic melanoma.

  To explore molecular factors associated with evolution and resistance in melanoma evolution, we multi-lesion sequenced primary and metastatic sites collected from autopsy in seven patients.

  Study EGAS00001003582

• CASCADE metastatic melanoma study

  In this study we analyse the evolution of human melanoma from early to late disease in patients by sampling their tumours at multiple sites and times. Whole exome and genome sequencing data from tumour samples reveals only limited gain of point mutations generally, with net mutational loss in some metastases. In contrast, melanoma evolution is dominated by whole genome doubling and large-scale aneuploidy, in which widespread loss of heterozygosity sculpts the burden of point mutations, neoantigens and structural variants even in treatment-naïve and primary cutaneous melanomas in some patients. These results imply that dysregulation of genomic integrity is a key driver of selective clonal advantage during melanoma progression.

  Study EGAS00001004950

• Assessment of cannabidiol and Δ9-tetrahydrocannabiol in mouse models of medulloblastoma

  Phytocannabinoids Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) have been demonstrated to exhibit anti-cancer activity in preclinical models of brain cancer leading to new clinical trials for adults with glioblastoma. We describe here the first report that has investigated a role for THC and CBD in paediatric brain cancer. Cannabinoids had cytotoxic activity against medulloblastoma and ependymoma cells in vitro, functioning in part through the inhibition of cell cycle progression and the induction of autophagy. Despite these effects in vitro, when tested in orthotopic mouse models of medulloblastoma or ependymoma, no impact on animal survival was observed. Furthermore, cannabinoids neither enhanced nor impaired conventional chemotherapy in a medulloblastoma mouse model. These data show that while THC and CBD do have some effects on medulloblastoma and ependymoma cells, are well tolerated and have minimal adverse effects, they do not appear to elicit any survival benefit in preclinical models of paediatric brain cancer.

  Study EGAS00001004963