883 research outputs found

    Transcriptional changes in trichothiodystrophy cells

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    Mutations in three of the genes encoding the XPB, XPD and TTDA components of transcription factor TFIIH can result in the clinical phenotype of trichothiodystrophy (TTD). Different mutations in XPB and XPD can instead cause xeroderma pigmentosum (XP). The completely different features of these disorders have been attributed to TTD being a transcription syndrome. In order to detect transcriptional differences between TTD and XP cells from the XP-D complementation group, we have compared gene expression profiles in cultured fibroblasts from normal, XP and TTD donors. Although we detected transcriptional differences between individual cell strains, using an algorithm of moderate stringency, we did not identify any genes whose expression was reproducibly different in proliferating fibroblasts from each type of donor. Following UV-irradiation, many genes were up- and down-regulated in all three cell types. The microarray analysis indicated some apparent differences between the different donor types, but on more detailed inspection, these turned out to be false positives. We conclude that there are minimal differences in gene expression in proliferating fibroblasts from TTD, XP-D and normal donors

    Magnetic fields in solar plage regions: insights from high-sensitivity spectropolarimetry

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    Plage regions are patches of concentrated magnetic field in the Sun's atmosphere where hot coronal loops are rooted. While previous studies have shed light on the properties of plage magnetic fields in the photosphere, there are still challenges in measuring the overlying chromospheric magnetic fields, which are crucial to understanding the overall heating and dynamics. Here, we utilize high-sensitivity, spectropolarimetric data obtained by the four-meter Daniel K. Inouye Solar Telescope (DKIST) to investigate the dynamic environment and magnetic field stratification of an extended, decaying plage region. The data show strong circular polarization signals in both plage cores and surrounding fibrils. Notably, weak linear polarization signals clearly differentiate between plage patches and the fibril canopy, where they are relatively stronger. Inversions of the Ca II 8542 A˚\mathring{A} spectra show an imprint of the fibrils in the chromospheric magnetic field, with typical field strength values ranging from ∼\sim 200-300 G in fibrils. We confirm the weak correlation between field strength and cooling rates in the lower chromosphere. Additionally, we observe supersonic downflows and strong velocity gradients in the plage periphery, indicating dynamical processes occurring in the chromosphere. These findings contribute to our understanding of the magnetic field and dynamics within plages, emphasizing the need for further research to explore the expansion of magnetic fields with height and the three-dimensional distribution of heating rates in the lower chromosphere.Comment: 17 pages, 8 figures, accepted for publication in ApJ

    PARP inhibition utilized in combination therapy with Olaparib-Temozolomide to achieve disease stabilization in a rare case of BRCA1-mutant, metastatic myxopapillary ependymoma.

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    Myxopapillary ependymoma (MPE) is a primary tumor of the central nervous system (CNS), characteristically an indolent malignancy involving the spinal conus medullaris, Filum terminale or cauda equina. We present a rare case of MPE, recurrent in the pelvic soft tissue with eventual pleural and intra-pulmonary metastasis. Refractory to repeated gross resection, adjuvant radiotherapy, platinum-based chemotherapy and temozolomide exploitation of mutant somatic BRCA1 status with the addition of a poly (ADP-ribose); polymerase inhibitor (PARPi) in a novel combination regimen with olaparib-temozolomide (OT) has achieved stable radiological disease after 10 cycles

    Retargeted adenoviruses for radiation-guided gene delivery

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    The combination of radiation with radiosensitizing gene delivery or oncolytic viruses promises to provide an advantage that could improve the therapeutic results for glioblastoma. X-rays can induce significant molecular changes in cancer cells. We isolated the GIRLRG peptide that binds to radiation-inducible 78 kDa glucose-regulated protein (GRP78), which is overexpressed on the plasma membranes of irradiated cancer cells and tumor-associated microvascular endothelial cells. The goal of our study was to improve tumor-specific adenovirus-mediated gene delivery by selectively targeting the adenovirus binding to this radiation-inducible protein. We employed an adenoviral fiber replacement approach to conduct a study of the targeting utility of GRP78-binding peptide. We have developed fiber-modified adenoviruses encoding the GRP78-binding peptide inserted into the fiber-fibritin. We have evaluated the reporter gene expression of fiber-modified adenoviruses in vitro using a panel of glioma cells and a human D54MG tumor xenograft model. The obtained results demonstrated that employment of the GRP78-binding peptide resulted in increased gene expression in irradiated tumors following infection with fiber-modified adenoviruses, compared with untreated tumor cells. These studies demonstrate the feasibility of adenoviral retargeting using the GRP78-binding peptide that selectively recognizes tumor cells responding to radiation treatment

    Combination of RGD Compound and Low-Dose Paclitaxel Induces Apoptosis in Human Glioblastoma Cells

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    ) peptide, to human glioblastoma U87MG cells with combination of low dose Paclitaxel (PTX) pre-treatment to augment therapeutic activity for RGD peptide-induced apoptosis. peptide induced U87MG programmed cell death. The increased expression of PTX-induced integrin-αvβ3 was correlated with the enhanced apoptosis in U87MG cells.This study provides a novel concept of targeting integrin-αvβ3 with RGD peptides in combination with low-dose PTX pre-treatment to improve efficiency in human glioblastoma treatment

    Understanding the dynamics of Toll-like Receptor 5 response to flagellin and its regulation by estradiol

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    © 2017 The Author(s). Toll-like receptors (TLRs) are major players of the innate immune system. Once activated, they trigger a signalling cascade that leads to NF-ΰ B translocation from the cytoplasm to the nucleus. Single cell analysis shows that NF-ΰ B signalling dynamics are a critical determinant of transcriptional regulation. Moreover, the outcome of innate immune response is also affected by the cross-talk between TLRs and estrogen signalling. Here, we characterized the dynamics of TLR5 signalling, responsible for the recognition of flagellated bacteria, and those changes induced by estradiol in its signalling at the single cell level. TLR5 activation in MCF7 cells induced a single and sustained NF-k B translocation into the nucleus that resulted in high NF-k B transcription activity. The overall magnitude of NF-k B transcription activity was not influenced by the duration of the stimulus. No significant changes are observed in the dynamics of NF-k B translocation to the nucleus when MCF7 cells are incubated with estradiol. However, estradiol significantly decreased NF-k B transcriptional activity while increasing TLR5-mediated AP-1 transcription. The effect of estradiol on transcriptional activity was dependent on the estrogen receptor activated. This fine tuning seems to occur mainly in the nucleus at the transcription level rather than affecting the translocation of the NF-k B transcription factor

    Cytoplasmic p53 couples oncogene-driven glucose metabolism to apoptosis and is a therapeutic target in glioblastoma.

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    Cross-talk among oncogenic signaling and metabolic pathways may create opportunities for new therapeutic strategies in cancer. Here we show that although acute inhibition of EGFR-driven glucose metabolism induces only minimal cell death, it lowers the apoptotic threshold in a subset of patient-derived glioblastoma (GBM) cells. Mechanistic studies revealed that after attenuated glucose consumption, Bcl-xL blocks cytoplasmic p53 from triggering intrinsic apoptosis. Consequently, targeting of EGFR-driven glucose metabolism in combination with pharmacological stabilization of p53 with the brain-penetrant small molecule idasanutlin resulted in synthetic lethality in orthotopic glioblastoma xenograft models. Notably, neither the degree of EGFR-signaling inhibition nor genetic analysis of EGFR was sufficient to predict sensitivity to this therapeutic combination. However, detection of rapid inhibitory effects on [18F]fluorodeoxyglucose uptake, assessed through noninvasive positron emission tomography, was an effective predictive biomarker of response in vivo. Together, these studies identify a crucial link among oncogene signaling, glucose metabolism, and cytoplasmic p53, which may potentially be exploited for combination therapy in GBM and possibly other malignancies
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