Kooperativer Bibliotheksverbund

Berlin Brandenburg


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  • 1
    In: Neuro-Oncology, 2018, Vol. 20(suppl6), pp.vi77-vi78
    Description: ONC201 is the first selective antagonist of dopamine receptor D2 (DRD2) and D3 (DRD3) for clinical oncology that has exhibited preliminary clinical activity in high grade gliomas. We investigated DRD2 dysregulation in glioma and its role in ONC201 efficacy. Investigating CRISPR screens across a spectrum of cancer revealed that glioma cell lines had the highest DRD2 gene essentiality scores, indicating that glioma is a tumor type with the most vulnerability to DRD2 antagonism. Investigation of TCGA revealed that DRD2 is highly expressed in glioblastoma relative to other dopamine receptor family members and is associated with a relatively poor clinical prognosis. Tissue microarray analysis confirmed DRD2 overexpression in glioblastoma relative to normal brain. A linear correlation between DRD2 mRNA and ONC201 GI50 was observed among NCI60 glioblastoma cell lines. Similarly, we found a significant concordance between a cell line’s sensitivity to ONC201 within the Genomics of Drug Sensitivity in Cancer (GDSC) panel and its DRD2 gene essentiality score. Next, we ranked the relative contribution of each dopamine receptor to ONC201 efficacy using a bioinformatics approach based on a generalized linear model. We found that the strongest negative contributor was DRD2 – where a negative contribution denotes a decreased IC50 value as expression increases. Interestingly, DRD5, a D1-like dopamine receptor that counteracts DRD2 signaling, was measured as having the highest positive score – indicating that low expression of DRD5 was correlated with ONC201 efficacy. DRD5 expression was significantly inversely correlated with ONC201 potency in the NCI60 and GDSC datasets. Furthermore, a missense DRD5 mutation was identified in tumor cells with acquired resistance to ONC201. Resistance could be recapitulated with overexpression of the mutant or wild-type DRD5 gene. In conclusion, DRD2 dysregulation and DRD5 expression predict preclinical ONC201 glioma sensitivity that may be used to identify additional settings for clinical evaluation.
    Keywords: Medicine;
    ISSN: 1522-8517
    E-ISSN: 1523-5866
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    In: Nature methods, 2010, Vol.7(4), p.325-330
    Description: The type-III secretion system (T3SS) enables gram-negative bacteria to inject effector proteins into eukaryotic host cells. Upon entry, T3SS effectors work cooperatively to reprogram host cells, enabling bacterial survival. Progress in understanding when and where effectors localize within host cells has been hindered by a dearth of tools to study these proteins in the native cellular environment. We report a method to label and track T3SS effectors during infection using a split-GFP system. The breadth of this technique is demonstrated by labeling three effectors from Salmonella (PipB2, SteA, and SteC) and characterizing their localizations within host cells. PipB2 displays highly dynamic behavior on tubules emanating from the Salmonella containing vacuole labeled with both endo- and exocytic markers. SteA is preferentially enriched on tubules localizing with Golgi markers. This segregation suggests effector targeting and localization may play a functional role during infection.
    Keywords: Article
    ISSN: 1548-7091
    E-ISSN: 1548-7105
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    Language: English
    In: Clinical cancer research : an official journal of the American Association for Cancer Research, 17 December 2018
    Description: Dopamine receptor D2 (DRD2) is a G protein-coupled receptor antagonized by ONC201, an anti-cancer small molecule in clinical trials for high grade gliomas and other malignancies. DRD5 is a dopamine receptor family member that opposes DRD2 signaling. We investigated the expression of these dopamine receptors in cancer and their influence on tumor cell sensitivity to ONC201. The Cancer Genome Atlas was used to determine DRD2/DRD5 expression broadly across human cancers. Cell viability assays were performed with ONC201 in 〉1,000 Genomic of Drug Sensitivity in Cancer and NCI60 cell lines. Immunohistochemistry staining of DRD2/DRD5 was performed in tissue microarrays and archival tumor tissues of glioblastoma patients treated with ONC201. Whole exome sequencing was performed in RKO cells with and without acquired ONC201 resistance. Wild-type and mutant DRD5 constructs were generated for overexpression studies. DRD2 overexpression broadly occurs across tumor types and is associated with a poor prognosis. Whole exome sequencing of cancer cells with acquired resistance to ONC201 revealed a de novo Q366R mutation in the DRD5 gene. Expression of Q366R DRD5 was sufficient to induce tumor cell apoptosis, consistent with a gain-of-function. DRD5 overexpression in glioblastoma cells enhanced DRD2/DRD5 heterodimers and DRD5 expression was inversely correlated with innate tumor cell sensitivity to ONC201. Investigation of archival tumor samples from recurrent glioblastoma patients treated with ONC201 revealed that low DRD5 expression was associated with relatively superior clinical outcomes. These results implicate DRD5 as a negative regulator of DRD2 signaling and tumor sensitivity to ONC201 DRD2 antagonism.
    ISSN: 1078-0432
    E-ISSN: 15573265
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  • 8
    Language: English
    In: Biophysical Journal, February 2009, Vol.96(3), pp.539a-539a
    Keywords: Biology
    ISSN: 0006-3495
    E-ISSN: 1542-0086
    Source: ScienceDirect Journals (Elsevier)
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  • 9
    Language: English
    In: Chemistry & Biology, 2008, Vol.15(6), pp.619-628
    Description: Gram-negative pathogenic bacteria such as utilize the type III secretion system to inject bacterial effector proteins into a host cell. Upon entry, these effectors bind mammalian cell proteins, hijack cellular signaling pathways, and redirect cellular function, thus enabling bacterial infection. In this study we use the FlAsH/tetracysteine labeling system to fluorescently tag specific effectors in to observe real-time secretion of these proteins into a mammalian host cell. The tetracysteine tag is genomically incorporated, thus preserving endogenous control of bacterial effectors. We demonstrate that two effectors, SopE2 and SptP, exhibit different secretion kinetics, as well as different rates of degradation within the host cell. These proteins respectively activate and suppress GTPase Cdc42, suggesting that there is a temporal hierarchy for effector delivery and persistence within the cell that is directly related to effector function.
    Keywords: Chembio ; Microbio ; Biology ; Chemistry ; Anatomy & Physiology
    ISSN: 1074-5521
    E-ISSN: 1879-1301
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  • 10
    Language: English
    In: Current Opinion in Chemical Biology, 2008, Vol.12(1), pp.60-65
    Description: Fluorescent biosensors allow researchers to image and quantify protein activity and small molecule signals in living cells with high spatial and temporal resolution. Genetically encoded sensors are coded by a DNA sequence and hence constructed entirely out of amino acids. These biosensors typically utilize light-emitting proteins, such as derivatives of the green fluorescent protein (GFP), and have been developed for a wide range of small molecules and enzyme activities. Fluorescent biosensors can be genetically targeted to distinct locations within cells, such as organelles and membranes. This feature facilitates elucidation of how protein activities and cellular signals are modulated in different regions of the cell. Improvements in the dynamic range and robustness of sensors have enabled high throughput screening for molecules that act as agonists or antagonists of protein function.
    Keywords: Chemistry ; Anatomy & Physiology
    ISSN: 1367-5931
    E-ISSN: 1879-0402
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