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Expression data from breast cancer tumors treated with a single window of the antiangiogenic agent Sunitinib

ABSTRACT: We have witnessed the rise and fall of antiangiogenic therapy in breast cancer (BC). Nevertheless, clinical remissions were observed in patients and we were interested in studying the activity of antiangiogenic drugs in BC. Inefficacy of sunitinib was observed in mouse models of metastatic BC, where evidence of enhanced metastasis was reported, and lack of efficacy of sunitinib-docetaxel combination was recently reported in a phase III clinical trial. Our aim was to understand the mechanisms and predictors of response to sunitinib in BC in a cohort of patients with untreated locally advanced or operable BC treated with an upfront window of single agent sunitinib, followed by the combination of sunitinib and docetaxel. We have used microarray profiing to monitor the transcriptional changes associated with three distinct stages of treatment: at diagnosis and prior to any treatment (t1), after an upfront window of single agent sunitinib (t2) and after the combined treatment of sunitinib and docetaxel (t3). In addtion, this microarray data also allowed us to observe the transcriptional changes associated with primary resistance to angiogenic therapy in 4 of 12 patients likely mediated by an adaptive transcriptional response to hypoxia in these resistant tumors. In BC patients this is the first demonstration of primary resistance to antiangiogenic therapy.

ORGANISM(S): Homo sapiens

PROVIDER: GSE58837 | GEO | 2016/12/31

SECONDARY ACCESSION(S): PRJNA253668

REPOSITORIES: GEO

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Project description:The feasibility of longitudinal metastatic biopsies for gene expression profiling in breast cancer is unexplored. Dynamic changes in gene expression can potentially predict efficacy of targeted cancer drugs. Patients enrolled in a phase III trial of metastatic breast cancer with sunitinib combined with docetaxel (SU+DOC) versus docetaxel alone (DOC) were offered to participate in a translational substudy comprising longitudinal fine needle aspiration biopsies (FNAB) and positron emission imaging before (T1) and two weeks after start of treatment (T2). Aspirated tumor material was used for microarray analysis, and treatment-induced changes (T2 versus T1) in gene expression and standardized uptake values were investigated. Twenty-one patients were included in the docetaxel ± sunitinib trial at Karolinska and 18 of them agreed to participate in the substudy. Of the 18 women enrolled, 8 were randomly assigned to SU+DOC and 10 to DOC. Metastatic FNAB were carried out in 17 of the 18 patients at both time points with no complications reported. Representative tumor material, sufficient for RNA extraction was obtained in 15 patients at T1 and 14 patients at T2. Matched samples both at T1 and T2 were obtained for 14 subjects, 7 in each arm. The main objective was to determine whether gene expression profiling is feasible using sequential, intra-patient FNAB. Secondary objectives were to identify potential biomarkers of early response by gene expression and/or functional imaging and to explore drug action in vivo by changes in gene expression. A Karolinska substudy of the docetaxel ± sunitinib phase III clinical trial utilising sequential metastatic fine needle aspiration biopsies (FNAB) and 18-F-2-fluoro-2-deoxyglucose positron emission tomography/computed tomography (FDG PET/CT). In brief, the randomized docetaxel ± sunitinib trial compared sunitinib combined with docetaxel (SU+DOC) versus docetaxel alone (DOC), as first line therapy in patients with HER2 negative metastatic breast cancer. Patients in the exploratory substudy were subjected to baseline FDG PET/CT assessment, followed by FNAB of one tumor lesion prior to start of treatment (Time point T1). FDG PET/CT and FNAB were repeated at Day 14 ± 1 (Time point T2) when sunitinib has achieved steady state.

Project description:Angiogenesis inhibitors, such as sunitinib, represent a promising strategy to improve glioblastoma (GBM) tumor response. In this study, we used the O6-methylguanine methyltransferase (MGMT)-negative GBM cell line U87MG stably transfected with MGMT (U87/MGMT) to assess whether MGMT expression affects the response to sunitinib. We showed that the addition of sunitinib to standard therapy (temozolomide [TMZ] and radiation therapy [RT]) significantly improved the response of MGMT positive but not of MGMT-negative cells. Gene expression profiling revealed alterations in the angiogenic profile, as well as differential expression of several receptor tyrosine kinases targeted by sunitinib. MGMT-positive cells displayed higher levels of vascular endothelial growth factor receptor 1 (VEGFR-1) compared with U87/EV cells, whereas they displayed decreased levels of VEGFR-2. Depleting MGMT using O6-benzylguanine suggested that the expression of these receptors was directly related to the MGMT status. Also, we showed that MGMT expression was associated with a dramatic increase in the soluble VEGFR-1/VEGFA ratio, thereby suggesting a decrease in bioactive VEGFA and a shift towards an antiangiogenic profile. The reduced angiogenic potential of MGMT-positive cells is supported by: (i) the decreased ability of their secreted factors to induce endothelial tube formation in vitro and (ii) their low tumorigenicity in vivo compared with the MGMT-negative cells. Our study is the first to show a direct link between MGMT expression and decreased angiogenicity and tumorigenicity of GBM cells and suggests the combination of sunitinib and standard therapy as an alternative strategy for GBM patients with MGMT-positive tumors. RNA was isolated from parental U87 (U87_EV) and MGMT-transfected U87 (U87_MGMT) triplicate. Pairwise gene expression differences were compared between the two cell lines. Features selected had more than 2-fold up-or down-regulated (P values of >05, unpaired Studentâs t-test with Bonferroni multiple testing correction) were identified. Database for annotation, visualization, and integrated discovery23 was used to identify enriched gene ontology (GO) biological themes.24 The GO data mining was conducted at a term specificity level 3.25 The EASE score was set at 0.05 and the minimum number of genes in a category was 5.

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Expression data from breast cancer tumors treated with a single window of the antiangiogenic agent Sunitinib

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